From 7299fc5247af52367f877e622a240425c81b78ac Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 00:34:00 -0500 Subject: [PATCH 01/30] feat: add cipher suite enumeration with raw TLS 1.3, QUIC, and key exchange probing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add --ciphers flag to connect command that enumerates all cipher suites a server supports across TLS 1.0–1.3, probes key exchange groups (including post-quantum hybrids), and tests QUIC/UDP alongside TCP. - Raw TLS 1.3 ClientHello prober (tls13probe.go): byte-level packet construction offering single cipher/group per probe, fully isolated with no shared state. Probes all 5 RFC 8446 suites and 7 named groups. - QUIC v1 Initial packet prober (quicprobe.go): HKDF key derivation, AES-128-GCM encryption, header protection per RFC 9001. - HelloRetryRequest detection via RFC 8446 §4.1.3 sentinel random. - Cipher output subgrouped by TLS version and key exchange type (ECDHE vs RSA) with forward secrecy labels. - QUIC section always visible when probed ("not supported" if rejected). - Good/weak security ratings for all cipher suites. Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 4 + EXAMPLES.md | 8 + README.md | 13 +- cmd/certkit/connect.go | 39 +- cmd/certkit/spinner.go | 86 ++++ connect.go | 640 ++++++++++++++++++++++++++++ connect_test.go | 918 +++++++++++++++++++++++++++++++++++++++++ go.mod | 2 +- quicprobe.go | 523 +++++++++++++++++++++++ testhelpers_test.go | 35 ++ tls13probe.go | 571 +++++++++++++++++++++++++ 11 files changed, 2831 insertions(+), 8 deletions(-) create mode 100644 cmd/certkit/spinner.go create mode 100644 quicprobe.go create mode 100644 tls13probe.go diff --git a/CHANGELOG.md b/CHANGELOG.md index 8d957b2..d223564 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added +- Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([`pending`]) +- Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([`pending`]) +- Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([`pending`]) +- Add QUIC/UDP cipher probing to `--ciphers` — automatically probes UDP 443 alongside TCP, shows "QUIC: not supported" when server rejects ([`pending`]) - Auto-generate CLI flag tables in README from Cobra command definitions via `go generate` ([#80]) - Add `gendocs` pre-commit hook and CI check to verify flag tables stay in sync ([#80]) - Add global `--json` persistent flag — all commands now support JSON output; overrides `--format` when both are set ([#80]) diff --git a/EXAMPLES.md b/EXAMPLES.md index ed3939c..dda4103 100644 --- a/EXAMPLES.md +++ b/EXAMPLES.md @@ -178,6 +178,14 @@ certkit connect example.com --crl certkit exits with code 2 if the certificate is revoked (via OCSP or CRL). +To enumerate all cipher suites the server supports with security ratings: + +```sh +certkit connect example.com --ciphers +``` + +Each cipher suite is rated `strong` (ECDHE + AEAD, all TLS 1.3 suites) or `weak` (CBC, static RSA, RC4, 3DES). Weak ciphers are listed with a warning recommending they be disabled. + For machine-readable output: ```sh diff --git a/README.md b/README.md index 6eb788b..d5aed96 100644 --- a/README.md +++ b/README.md @@ -155,12 +155,13 @@ Chain verification is always performed. When the input contains an embedded priv ### Connect Flags -| Flag | Default | Description | -| -------------- | ------- | -------------------------------------------- | -| `--crl` | `false` | Check CRL distribution points for revocation | -| `--format` | `text` | Output format: text, json | -| `--no-ocsp` | `false` | Disable automatic OCSP revocation check | -| `--servername` | | Override SNI hostname (defaults to host) | +| Flag | Default | Description | +| -------------- | ------- | ----------------------------------------------------------- | +| `--ciphers` | `false` | Enumerate all supported cipher suites with security ratings | +| `--crl` | `false` | Check CRL distribution points for revocation | +| `--format` | `text` | Output format: text, json | +| `--no-ocsp` | `false` | Disable automatic OCSP revocation check | +| `--servername` | | Override SNI hostname (defaults to host) | Port defaults to 443 if not specified. OCSP revocation status is checked automatically (best-effort); use `--no-ocsp` to disable. Use `--verbose` for extended details (serial, key info, signature algorithm, key usage, EKU). diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index f8d6ed0..e85b843 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -22,6 +22,7 @@ var ( connectFormat string connectCRL bool connectNoOCSP bool + connectCiphers bool ) var connectCmd = &cobra.Command{ @@ -32,12 +33,14 @@ and the full certificate chain. Port defaults to 443 if not specified. OCSP revocation status is checked automatically (best-effort). Use --no-ocsp to disable. Use --crl to also -check CRL distribution points. +check CRL distribution points. Use --ciphers to enumerate all cipher suites +the server supports with security ratings. Exits with code 2 if chain verification fails or the certificate is revoked.`, Example: ` certkit connect example.com certkit connect example.com:8443 certkit connect example.com --crl + certkit connect example.com --ciphers certkit connect example.com --servername alt.example.com certkit connect example.com --format json`, Args: cobra.ExactArgs(1), @@ -49,6 +52,7 @@ func init() { connectCmd.Flags().StringVar(&connectFormat, "format", "text", "Output format: text, json") connectCmd.Flags().BoolVar(&connectCRL, "crl", false, "Check CRL distribution points for revocation") connectCmd.Flags().BoolVar(&connectNoOCSP, "no-ocsp", false, "Disable automatic OCSP revocation check") + connectCmd.Flags().BoolVar(&connectCiphers, "ciphers", false, "Enumerate all supported cipher suites with security ratings") registerCompletion(connectCmd, completionInput{"format", fixedCompletion("text", "json")}) } @@ -67,6 +71,7 @@ type connectResultJSON struct { AIAFetched bool `json:"aia_fetched,omitempty"` OCSP *certkit.OCSPResult `json:"ocsp,omitempty"` CRL *certkit.CRLCheckResult `json:"crl,omitempty"` + CipherScan *certkit.CipherScanResult `json:"cipher_scan,omitempty"` Chain []connectCertJSON `json:"chain"` } @@ -100,6 +105,9 @@ func runConnect(cmd *cobra.Command, args []string) error { return fmt.Errorf("parsing address %q: %w", args[0], err) } + spin := newSpinner("Connecting…") + spin.Start() + ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Second) defer cancel() @@ -111,9 +119,32 @@ func runConnect(cmd *cobra.Command, args []string) error { CheckCRL: connectCRL, }) if err != nil { + spin.Stop() return fmt.Errorf("connecting to %s: %w", args[0], err) } + // Optional cipher suite enumeration. + if connectCiphers { + spin.SetMessage("Scanning cipher suites…") + + cipherCtx, cipherCancel := context.WithTimeout(cmd.Context(), 60*time.Second) + defer cipherCancel() + cipherScan, scanErr := certkit.ScanCipherSuites(cipherCtx, certkit.ScanCipherSuitesInput{ + Host: host, + Port: port, + ServerName: connectServerName, + ProbeQUIC: true, + }) + if scanErr != nil { + spin.Stop() + return fmt.Errorf("scanning cipher suites: %w", scanErr) + } + result.CipherScan = cipherScan + result.Diagnostics = append(result.Diagnostics, certkit.DiagnoseCipherScan(cipherScan)...) + } + + spin.Stop() + now := time.Now() format := connectFormat @@ -136,6 +167,7 @@ func runConnect(cmd *cobra.Command, args []string) error { AIAFetched: result.AIAFetched, OCSP: result.OCSP, CRL: result.CRL, + CipherScan: result.CipherScan, } for _, cert := range result.PeerChain { cj := connectCertJSON{ @@ -175,6 +207,9 @@ func runConnect(cmd *cobra.Command, args []string) error { } else { fmt.Print(certkit.FormatConnectResult(result)) } + if result.CipherScan != nil { + fmt.Print(certkit.FormatCipherScanResult(result.CipherScan)) + } default: return fmt.Errorf("unsupported output format %q (use text or json)", format) } @@ -220,6 +255,8 @@ func formatConnectVerbose(r *certkit.ConnectResult, now time.Time) string { out.WriteString(certkit.FormatCRLLine(r.CRL)) } + out.WriteString(certkit.FormatCipherRatingLine(r.CipherScan)) + if r.ClientAuth != nil && r.ClientAuth.Requested { out.WriteString("Client Auth: requested\n") if len(r.ClientAuth.AcceptableCAs) > 0 { diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go new file mode 100644 index 0000000..b8227d8 --- /dev/null +++ b/cmd/certkit/spinner.go @@ -0,0 +1,86 @@ +package main + +import ( + "fmt" + "os" + "sync" + "time" + + "github.com/mattn/go-isatty" +) + +// spinner displays an animated progress indicator on stderr when the output +// is a terminal. It silently does nothing when piped or redirected. +type spinner struct { + mu sync.Mutex + msg string + stop chan struct{} + done chan struct{} + started bool +} + +// newSpinner creates a spinner with the given message. Call Start() to begin +// animating and Stop() when finished. The spinner only renders when stderr +// is a terminal — safe to use unconditionally. +func newSpinner(msg string) *spinner { + return &spinner{ + msg: msg, + stop: make(chan struct{}), + done: make(chan struct{}), + } +} + +// Start begins the spinner animation in a background goroutine. +func (s *spinner) Start() { + if !isatty.IsTerminal(os.Stderr.Fd()) && !isatty.IsCygwinTerminal(os.Stderr.Fd()) { + close(s.done) + return + } + + s.started = true + go s.run() +} + +// SetMessage updates the spinner text while it's running. +func (s *spinner) SetMessage(msg string) { + s.mu.Lock() + s.msg = msg + s.mu.Unlock() +} + +// Stop halts the spinner and clears the line. +func (s *spinner) Stop() { + if !s.started { + <-s.done + return + } + close(s.stop) + <-s.done +} + +var spinnerFrames = [...]string{"⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"} + +func (s *spinner) run() { + defer close(s.done) + + ticker := time.NewTicker(80 * time.Millisecond) + defer ticker.Stop() + + frame := 0 + for { + s.mu.Lock() + msg := s.msg + s.mu.Unlock() + + fmt.Fprintf(os.Stderr, "\r%s %s", spinnerFrames[frame%len(spinnerFrames)], msg) + frame++ + + select { + case <-s.stop: + // Clear the spinner line. + fmt.Fprintf(os.Stderr, "\r\033[K") + return + case <-ticker.C: + } + } +} diff --git a/connect.go b/connect.go index de4e2d3..2922a60 100644 --- a/connect.go +++ b/connect.go @@ -1,6 +1,7 @@ package certkit import ( + "cmp" "context" "crypto/tls" "crypto/x509" @@ -9,7 +10,9 @@ import ( "fmt" "log/slog" "net" + "slices" "strings" + "sync" "time" ) @@ -147,6 +150,9 @@ type ConnectResult struct { // CRL contains the leaf certificate's CRL revocation status. // Nil when CRL checking is not requested (CheckCRL is false). CRL *CRLCheckResult `json:"crl,omitempty"` + // CipherScan contains the cipher suite enumeration results. + // Nil when cipher scanning is not requested. + CipherScan *CipherScanResult `json:"cipher_scan,omitempty"` } // ConnectTLS connects to a TLS server and returns connection details including @@ -569,6 +575,638 @@ func FormatCRLLine(r *CRLCheckResult) string { return FormatCRLStatusLine("CRL: ", r) } +// CipherRating indicates the security quality of a cipher suite. +type CipherRating string + +const ( + // CipherRatingGood indicates TLS 1.3 suites or TLS 1.2 ECDHE+AEAD (GCM, ChaCha20-Poly1305). + CipherRatingGood CipherRating = "good" + // CipherRatingWeak indicates cipher suites that should be disabled: + // anything in Go's InsecureCipherSuites(), CBC-mode ciphers, or non-ECDHE key exchange. + CipherRatingWeak CipherRating = "weak" +) + +// CipherProbeResult describes a single cipher suite accepted by the server. +type CipherProbeResult struct { + // Name is the IANA cipher suite name (e.g. "TLS_AES_128_GCM_SHA256"). + Name string `json:"name"` + // ID is the numeric cipher suite identifier. + ID uint16 `json:"id"` + // Version is the TLS version string (e.g. "TLS 1.3"). + Version string `json:"version"` + // KeyExchange is the key exchange mechanism (e.g. "ECDHE", "RSA"). + KeyExchange string `json:"key_exchange"` + // Rating is the security quality assessment. + Rating CipherRating `json:"rating"` +} + +// CipherScanResult contains the results of a cipher suite enumeration. +type CipherScanResult struct { + // SupportedVersions lists the TLS versions the server supports (e.g. ["TLS 1.3", "TLS 1.2"]). + SupportedVersions []string `json:"supported_versions"` + // Ciphers lists all accepted cipher suites, sorted by version (descending) then rating. + Ciphers []CipherProbeResult `json:"ciphers"` + // QUICProbed is true when QUIC/UDP cipher probing was attempted. + QUICProbed bool `json:"quic_probed"` + // QUICCiphers lists TLS 1.3 cipher suites accepted over QUIC/UDP. + QUICCiphers []CipherProbeResult `json:"quic_ciphers,omitempty"` + // KeyExchanges lists accepted key exchange groups (classical and post-quantum). + KeyExchanges []KeyExchangeProbeResult `json:"key_exchanges,omitempty"` + // OverallRating is the worst rating among all accepted ciphers. + OverallRating CipherRating `json:"overall_rating"` +} + +// ScanCipherSuitesInput contains parameters for ScanCipherSuites. +type ScanCipherSuitesInput struct { + // Host is the hostname or IP to connect to. + Host string + // Port is the TCP port (default: "443"). + Port string + // ServerName overrides the SNI hostname (defaults to Host). + ServerName string + // Concurrency is the maximum number of parallel probe connections (default: 10). + Concurrency int + // ProbeQUIC enables QUIC/UDP cipher probing alongside TCP. + ProbeQUIC bool +} + +// cipherSuiteName returns a human-readable name for any TLS cipher suite. +// It extends tls.CipherSuiteName with the two CCM suites from RFC 8446 that +// Go doesn't implement (0x1304, 0x1305) and would otherwise show as hex. +func cipherSuiteName(id uint16) string { + switch id { + case 0x1304: + return "TLS_AES_128_CCM_SHA256" + case 0x1305: + return "TLS_AES_128_CCM_8_SHA256" + default: + return tls.CipherSuiteName(id) + } +} + +// keyExchangeName returns a human-readable name for a TLS named group. +// Go's CurveID.String() returns "CurveP256" etc.; we prefer "P-256". +func keyExchangeName(id tls.CurveID) string { + switch id { + case tls.CurveP256: + return "P-256" + case tls.CurveP384: + return "P-384" + case tls.CurveP521: + return "P-521" + default: + return id.String() + } +} + +// cipherKeyExchange returns the key exchange mechanism for a cipher suite. +// TLS 1.3 always uses ECDHE. For TLS 1.0–1.2, it's derived from the cipher name. +func cipherKeyExchange(name, version string) string { + if version == "TLS 1.3" { + return "ECDHE" + } + if strings.HasPrefix(name, "TLS_ECDHE_") { + return "ECDHE" + } + if strings.HasPrefix(name, "TLS_RSA_") { + return "RSA" + } + if strings.HasPrefix(name, "TLS_DHE_") { + return "DHE" + } + return "unknown" +} + +// kexRank returns a sort key for key exchange types (lower = better). +func kexRank(kex string) int { + switch kex { + case "ECDHE": + return 0 + case "DHE": + return 1 + case "RSA": + return 2 + default: + return 3 + } +} + +// RateCipherSuite returns the security rating for a cipher suite at a given TLS version. +func RateCipherSuite(cipherID uint16, tlsVersion uint16) CipherRating { + // TLS 1.3 suites are always good — they only use AEAD ciphers. + if tlsVersion == tls.VersionTLS13 { + return CipherRatingGood + } + + // Check if it's in Go's insecure list (RC4, 3DES, null ciphers). + for _, cs := range tls.InsecureCipherSuites() { + if cs.ID == cipherID { + return CipherRatingWeak + } + } + + // For TLS 1.0–1.2: look up the cipher suite name to classify. + name := tls.CipherSuiteName(cipherID) + + // Non-ECDHE key exchange (static RSA) is insecure — no forward secrecy. + if !strings.Contains(name, "ECDHE") { + return CipherRatingWeak + } + + // ECDHE + AEAD (GCM or ChaCha20-Poly1305) is good. + if strings.Contains(name, "GCM") || strings.Contains(name, "CHACHA20_POLY1305") { + return CipherRatingGood + } + + // ECDHE + CBC is weak (padding oracle attacks like BEAST, Lucky13). + return CipherRatingWeak +} + +// ScanCipherSuites probes a TLS server to enumerate all supported cipher suites +// and key exchange groups. TLS 1.3 ciphers are probed using raw ClientHello +// packets (all 5 RFC 8446 suites). TLS 1.0–1.2 ciphers are probed using Go's +// crypto/tls with a single-cipher config. Key exchange groups are probed via +// raw ClientHello with individual named groups. All probes run concurrently. +func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*CipherScanResult, error) { + if input.Host == "" { + return nil, fmt.Errorf("scanning cipher suites: host is required") + } + port := input.Port + if port == "" { + port = "443" + } + serverName := input.ServerName + if serverName == "" { + serverName = input.Host + } + concurrency := input.Concurrency + if concurrency <= 0 { + concurrency = 10 + } + + addr := net.JoinHostPort(input.Host, port) + + sem := make(chan struct{}, concurrency) + var mu sync.Mutex + var wg sync.WaitGroup + + // acquireSem tries to acquire a semaphore slot, returning false if the + // context is cancelled while waiting for a slot. + acquireSem := func() bool { + select { + case sem <- struct{}{}: + return true + case <-ctx.Done(): + return false + } + } + + // probeTimeout is the maximum time for a single probe attempt. This + // is independent of the parent context to prevent slow/stalling servers + // from blocking the entire scan. Each probe gets its own child context. + const probeTimeout = 2 * time.Second + + // Probe TLS 1.3 ciphers using raw ClientHello packets. Each probe is + // fully isolated — no shared state, safe for concurrent use. + var results []CipherProbeResult + for _, id := range tls13CipherSuites { + if ctx.Err() != nil { + break + } + if !acquireSem() { + break + } + wg.Add(1) + go func(cipherID uint16) { + defer wg.Done() + defer func() { <-sem }() + + probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) + defer probeCancel() + + if probeTLS13Cipher(probeCtx, addr, serverName, cipherID) { + r := CipherProbeResult{ + Name: cipherSuiteName(cipherID), + ID: cipherID, + Version: "TLS 1.3", + KeyExchange: "ECDHE", + Rating: RateCipherSuite(cipherID, tls.VersionTLS13), + } + mu.Lock() + results = append(results, r) + mu.Unlock() + } + }(id) + } + + // Collect all TLS 1.0–1.2 cipher suites to probe. + type probeTask struct { + id uint16 + version uint16 + } + var tasks []probeTask + allSuites := append(tls.CipherSuites(), tls.InsecureCipherSuites()...) + for _, cs := range allSuites { + for _, v := range cs.SupportedVersions { + if v >= tls.VersionTLS10 && v <= tls.VersionTLS12 { + tasks = append(tasks, probeTask{id: cs.ID, version: v}) + } + } + } + + // Probe TLS 1.0–1.2 ciphers concurrently using Go's crypto/tls. + for _, task := range tasks { + if ctx.Err() != nil { + break + } + if !acquireSem() { + break + } + + wg.Add(1) + go func(t probeTask) { + defer wg.Done() + defer func() { <-sem }() + + probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) + defer probeCancel() + + if probeCipher(probeCtx, addr, serverName, t.id, t.version) { + name := cipherSuiteName(t.id) + r := CipherProbeResult{ + Name: name, + ID: t.id, + Version: tlsVersionString(t.version), + KeyExchange: cipherKeyExchange(name, tlsVersionString(t.version)), + Rating: RateCipherSuite(t.id, t.version), + } + mu.Lock() + results = append(results, r) + mu.Unlock() + } + }(task) + } + + // Probe key exchange groups. TLS 1.3 groups use raw ClientHello packets; + // classical groups also try TLS 1.2 (via crypto/tls CurvePreferences) + // to cover servers that don't support TLS 1.3. + var keyExchanges []KeyExchangeProbeResult + kxSeen := make(map[tls.CurveID]bool) + var kxMu sync.Mutex + for _, gid := range keyExchangeGroups { + if ctx.Err() != nil { + break + } + if !acquireSem() { + break + } + wg.Add(1) + go func(groupID tls.CurveID) { + defer wg.Done() + defer func() { <-sem }() + + probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) + defer probeCancel() + + accepted := probeKeyExchangeGroup(probeCtx, addr, serverName, groupID) + + // For classical (non-PQ) groups, also probe TLS 1.0–1.2 if TLS 1.3 didn't work. + if !accepted && !isPQKeyExchange(groupID) { + probeCtx2, probeCancel2 := context.WithTimeout(ctx, probeTimeout) + defer probeCancel2() + accepted = probeKeyExchangeGroupLegacy(probeCtx2, addr, serverName, groupID) + } + + if accepted { + kxMu.Lock() + if !kxSeen[groupID] { + kxSeen[groupID] = true + keyExchanges = append(keyExchanges, KeyExchangeProbeResult{ + Name: keyExchangeName(groupID), + ID: uint16(groupID), + PostQuantum: isPQKeyExchange(groupID), + }) + } + kxMu.Unlock() + } + }(gid) + } + + // Probe QUIC/UDP cipher suites if requested. + var quicCiphers []CipherProbeResult + if input.ProbeQUIC { + quicAddr := net.JoinHostPort(input.Host, port) + for _, id := range tls13CipherSuites { + if ctx.Err() != nil { + break + } + if !acquireSem() { + break + } + wg.Add(1) + go func(cipherID uint16) { + defer wg.Done() + defer func() { <-sem }() + + probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) + defer probeCancel() + + if probeQUICCipher(probeCtx, quicAddr, serverName, cipherID) { + r := CipherProbeResult{ + Name: cipherSuiteName(cipherID), + ID: cipherID, + Version: "TLS 1.3", + KeyExchange: "ECDHE", + Rating: RateCipherSuite(cipherID, tls.VersionTLS13), + } + mu.Lock() + quicCiphers = append(quicCiphers, r) + mu.Unlock() + } + }(id) + } + } + + wg.Wait() + + if ctx.Err() != nil { + return nil, fmt.Errorf("scanning cipher suites: %w", ctx.Err()) + } + + // Sort ciphers: version descending, then kex type (ECDHE before RSA), + // then rating (good before weak), then name. + slices.SortFunc(results, func(a, b CipherProbeResult) int { + if c := cmp.Compare(tlsVersionRank(b.Version), tlsVersionRank(a.Version)); c != 0 { + return c + } + if c := cmp.Compare(kexRank(a.KeyExchange), kexRank(b.KeyExchange)); c != 0 { + return c + } + if c := cmp.Compare(ratingRank(a.Rating), ratingRank(b.Rating)); c != 0 { + return c + } + return cmp.Compare(a.Name, b.Name) + }) + + // Sort key exchanges: PQ first, then by ID descending for consistent output. + slices.SortFunc(keyExchanges, func(a, b KeyExchangeProbeResult) int { + if a.PostQuantum != b.PostQuantum { + if a.PostQuantum { + return -1 + } + return 1 + } + return cmp.Compare(b.ID, a.ID) + }) + + // Compute supported versions and overall rating. + versionSet := make(map[string]bool) + overall := CipherRatingGood + for _, r := range results { + versionSet[r.Version] = true + if ratingRank(r.Rating) > ratingRank(overall) { + overall = r.Rating + } + } + + var versions []string + for v := range versionSet { + versions = append(versions, v) + } + slices.SortFunc(versions, func(a, b string) int { + return cmp.Compare(tlsVersionRank(b), tlsVersionRank(a)) + }) + + // Sort QUIC ciphers by name for consistent output. + slices.SortFunc(quicCiphers, func(a, b CipherProbeResult) int { + return cmp.Compare(a.Name, b.Name) + }) + + return &CipherScanResult{ + SupportedVersions: versions, + Ciphers: results, + QUICProbed: input.ProbeQUIC, + QUICCiphers: quicCiphers, + KeyExchanges: keyExchanges, + OverallRating: overall, + }, nil +} + +// emptyClientCert is a GetClientCertificate callback that returns an empty +// certificate. This is needed so the handshake progresses far enough to +// negotiate a cipher suite even when the server requests client auth (mTLS). +func emptyClientCert(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) { + return &tls.Certificate{}, nil +} + +// probeCipher attempts a TLS handshake offering only the specified cipher suite at the given version. +// Returns true if the server accepted the cipher, even if the handshake +// ultimately fails (e.g. mTLS rejection after cipher negotiation). +func probeCipher(ctx context.Context, addr, serverName string, cipherID uint16, version uint16) bool { + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", addr) + if err != nil { + return false + } + tlsConn := tls.Client(conn, &tls.Config{ + ServerName: serverName, + InsecureSkipVerify: true, //nolint:gosec // Cipher probing doesn't need cert verification. + MinVersion: version, + MaxVersion: version, + CipherSuites: []uint16{cipherID}, + GetClientCertificate: emptyClientCert, + }) + defer func() { _ = tlsConn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = tlsConn.SetDeadline(deadline) + } + if tlsConn.HandshakeContext(ctx) == nil { + return true + } + // Handshake failed, but check if the server negotiated our cipher before aborting. + state := tlsConn.ConnectionState() + return state.Version == version && state.CipherSuite == cipherID +} + +// ecdheOnlyCipherSuites contains only ECDHE-based TLS 1.0–1.2 cipher suites. +// Used by probeKeyExchangeGroupLegacy to ensure the server must use ECDHE key +// exchange — without this, servers that pick RSA key exchange would incorrectly +// appear to support any offered curve. +var ecdheOnlyCipherSuites = func() []uint16 { + var ids []uint16 + for _, cs := range tls.CipherSuites() { + if strings.Contains(cs.Name, "ECDHE") { + ids = append(ids, cs.ID) + } + } + return ids +}() + +// probeKeyExchangeGroupLegacy attempts a TLS 1.0–1.2 handshake using a single +// CurvePreferences entry and returns true if the server accepts the group. Only +// ECDHE cipher suites are offered so the handshake fails if the server doesn't +// support the offered curve (RSA key exchange would bypass curve negotiation). +func probeKeyExchangeGroupLegacy(ctx context.Context, addr, serverName string, groupID tls.CurveID) bool { + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", addr) + if err != nil { + return false + } + tlsConn := tls.Client(conn, &tls.Config{ + ServerName: serverName, + InsecureSkipVerify: true, //nolint:gosec // Probing doesn't need cert verification. + MinVersion: tls.VersionTLS10, + MaxVersion: tls.VersionTLS12, + CipherSuites: ecdheOnlyCipherSuites, + CurvePreferences: []tls.CurveID{groupID}, + GetClientCertificate: emptyClientCert, + }) + defer func() { _ = tlsConn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = tlsConn.SetDeadline(deadline) + } + if tlsConn.HandshakeContext(ctx) == nil { + return true + } + // Handshake may fail due to mTLS rejection, but the key exchange + // succeeded if a TLS version was negotiated (happens before client auth). + state := tlsConn.ConnectionState() + return state.Version != 0 +} + +// tlsVersionRank returns a sort key for TLS versions (higher = newer). +func tlsVersionRank(version string) int { + switch version { + case "TLS 1.3": + return 4 + case "TLS 1.2": + return 3 + case "TLS 1.1": + return 2 + case "TLS 1.0": + return 1 + default: + return 0 + } +} + +// ratingRank returns a sort key for cipher ratings (lower = better). +func ratingRank(r CipherRating) int { + switch r { + case CipherRatingGood: + return 0 + case CipherRatingWeak: + return 1 + default: + return 2 + } +} + +// DiagnoseCipherScan inspects cipher scan results and returns diagnostics +// for weak cipher suites that should be disabled. +func DiagnoseCipherScan(r *CipherScanResult) []ChainDiagnostic { + if r == nil { + return nil + } + + var weak int + for _, c := range r.Ciphers { + if c.Rating == CipherRatingWeak { + weak++ + } + } + if weak == 0 { + return nil + } + + return []ChainDiagnostic{{ + Check: "weak-cipher", + Status: "warn", + Detail: fmt.Sprintf("server accepts %d weak cipher suite(s) that should be disabled", weak), + }} +} + +// FormatCipherRatingLine formats a one-line summary for the connect header block, +// positioned alongside Host/Protocol/OCSP etc. +func FormatCipherRatingLine(r *CipherScanResult) string { + if r == nil || len(r.Ciphers) == 0 { + return "" + } + + var strong, weak int + for _, c := range r.Ciphers { + if c.Rating == CipherRatingGood { + strong++ + } else { + weak++ + } + } + + return fmt.Sprintf("Ciphers: %s (%d good, %d weak)\n", r.OverallRating, strong, weak) +} + +// kexLabel returns the display label for a key exchange type in the cipher +// suite subgroup header, e.g. "ECDHE" or "RSA, no forward secrecy". +func kexLabel(kex string) string { + if kex == "RSA" { + return "RSA, no forward secrecy" + } + return kex +} + +// FormatCipherScanResult formats the cipher suite list as human-readable text. +func FormatCipherScanResult(r *CipherScanResult) string { + if len(r.Ciphers) == 0 { + return "" + } + + var out strings.Builder + fmt.Fprintf(&out, "\nCipher suites (%d supported):\n", len(r.Ciphers)) + + // Group by version, then subgroup by key exchange type. + currentVersion := "" + currentKex := "" + for _, c := range r.Ciphers { + if c.Version != currentVersion || c.KeyExchange != currentKex { + if currentVersion != "" { + out.WriteByte('\n') + } + currentVersion = c.Version + currentKex = c.KeyExchange + fmt.Fprintf(&out, " %s (%s):\n", currentVersion, kexLabel(currentKex)) + } + fmt.Fprintf(&out, " [%s] %s\n", c.Rating, c.Name) + } + + // QUIC cipher suites (if probed). + if r.QUICProbed { + if len(r.QUICCiphers) > 0 { + fmt.Fprintf(&out, "\nQUIC cipher suites (%d supported):\n", len(r.QUICCiphers)) + for _, c := range r.QUICCiphers { + fmt.Fprintf(&out, " [%s] %s\n", c.Rating, c.Name) + } + } else { + out.WriteString("\nQUIC: not supported\n") + } + } + + // Key exchange groups (forward secrecy). + if len(r.KeyExchanges) > 0 { + fmt.Fprintf(&out, "\nKey exchange groups (%d supported, forward secrecy):\n", len(r.KeyExchanges)) + for _, g := range r.KeyExchanges { + if g.PostQuantum { + fmt.Fprintf(&out, " %s (post-quantum)\n", g.Name) + } else { + fmt.Fprintf(&out, " %s\n", g.Name) + } + } + } + + return out.String() +} + // FormatConnectResult formats a ConnectResult as human-readable text. func FormatConnectResult(r *ConnectResult) string { var out strings.Builder @@ -597,6 +1235,8 @@ func FormatConnectResult(r *ConnectResult) string { out.WriteString(FormatCRLLine(r.CRL)) } + out.WriteString(FormatCipherRatingLine(r.CipherScan)) + if r.ClientAuth != nil && r.ClientAuth.Requested { if len(r.ClientAuth.AcceptableCAs) > 0 { fmt.Fprintf(&out, "Client Auth: requested (%d acceptable CA(s))\n", len(r.ClientAuth.AcceptableCAs)) diff --git a/connect_test.go b/connect_test.go index 833b5e0..9426a53 100644 --- a/connect_test.go +++ b/connect_test.go @@ -8,11 +8,13 @@ import ( "crypto/tls" "crypto/x509" "crypto/x509/pkix" + "encoding/hex" "math/big" "net" "net/http" "net/http/httptest" "strings" + "sync" "sync/atomic" "testing" "time" @@ -1169,6 +1171,375 @@ func TestConnectTLS_CRL_AIAFetchedIssuer(t *testing.T) { } } +func TestRateCipherSuite(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + cipherID uint16 + tlsVersion uint16 + want CipherRating + }{ + // TLS 1.3 — always excellent. + { + name: "TLS 1.3 AES-128-GCM", + cipherID: tls.TLS_AES_128_GCM_SHA256, + tlsVersion: tls.VersionTLS13, + want: CipherRatingGood, + }, + { + name: "TLS 1.3 AES-256-GCM", + cipherID: tls.TLS_AES_256_GCM_SHA384, + tlsVersion: tls.VersionTLS13, + want: CipherRatingGood, + }, + { + name: "TLS 1.3 CHACHA20-POLY1305", + cipherID: tls.TLS_CHACHA20_POLY1305_SHA256, + tlsVersion: tls.VersionTLS13, + want: CipherRatingGood, + }, + // TLS 1.2 ECDHE + AEAD — excellent. + { + name: "TLS 1.2 ECDHE-RSA-AES128-GCM", + cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, + tlsVersion: tls.VersionTLS12, + want: CipherRatingGood, + }, + { + name: "TLS 1.2 ECDHE-ECDSA-AES256-GCM", + cipherID: tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, + tlsVersion: tls.VersionTLS12, + want: CipherRatingGood, + }, + { + name: "TLS 1.2 ECDHE-RSA-CHACHA20-POLY1305", + cipherID: tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, + tlsVersion: tls.VersionTLS12, + want: CipherRatingGood, + }, + // TLS 1.2 ECDHE + CBC — insecure. + { + name: "TLS 1.2 ECDHE-RSA-AES128-CBC-SHA256", + cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + { + name: "TLS 1.2 ECDHE-ECDSA-AES128-CBC-SHA", + cipherID: tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + // TLS 1.2 static RSA — insecure (no forward secrecy). + { + name: "TLS 1.2 RSA-AES128-GCM", + cipherID: tls.TLS_RSA_WITH_AES_128_GCM_SHA256, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + // Insecure cipher suites (from tls.InsecureCipherSuites). + { + name: "TLS 1.2 RSA-RC4-SHA (insecure list)", + cipherID: tls.TLS_RSA_WITH_RC4_128_SHA, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + { + name: "TLS 1.2 RSA-3DES-EDE-CBC-SHA (insecure list)", + cipherID: tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + { + name: "TLS 1.2 ECDHE-RSA-RC4-SHA (insecure list)", + cipherID: tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + // TLS 1.0 ECDHE + GCM — still excellent (GCM is good regardless of TLS version). + { + name: "TLS 1.0 ECDHE-RSA-AES128-GCM", + cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, + tlsVersion: tls.VersionTLS10, + want: CipherRatingGood, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + got := RateCipherSuite(tt.cipherID, tt.tlsVersion) + if got != tt.want { + t.Errorf("RateCipherSuite(0x%04x, 0x%04x) = %q, want %q", + tt.cipherID, tt.tlsVersion, got, tt.want) + } + }) + } +} + +func TestScanCipherSuites(t *testing.T) { + t.Parallel() + + // Create a TLS server that only accepts specific cipher suites. + ca := generateTestCA(t, "Cipher Scan CA") + leaf := generateTestLeafCert(t, ca) + + tlsCert := tls.Certificate{ + Certificate: [][]byte{leaf.DER, ca.CertDER}, + PrivateKey: leaf.Key, + } + + port := startTLSServerWithConfig(t, &tls.Config{ + Certificates: []tls.Certificate{tlsCert}, + MinVersion: tls.VersionTLS12, + MaxVersion: tls.VersionTLS13, + CipherSuites: []uint16{ + tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, + tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, + }, + }) + + ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) + defer cancel() + + result, err := ScanCipherSuites(ctx, ScanCipherSuitesInput{ + Host: "127.0.0.1", + Port: port, + Concurrency: 5, + }) + if err != nil { + t.Fatalf("ScanCipherSuites failed: %v", err) + } + + if len(result.Ciphers) == 0 { + t.Fatal("no ciphers detected") + } + + // Should detect TLS 1.3 suites (all 3). + tls13Count := 0 + for _, c := range result.Ciphers { + if c.Version == "TLS 1.3" { + tls13Count++ + } + } + if tls13Count != 3 { + t.Errorf("expected 3 TLS 1.3 ciphers, got %d", tls13Count) + } + + // Should detect the two TLS 1.2 ECDHE-ECDSA-GCM ciphers we configured. + tls12Names := make(map[string]bool) + for _, c := range result.Ciphers { + if c.Version == "TLS 1.2" { + tls12Names[c.Name] = true + } + } + for _, want := range []string{ + "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", + "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", + } { + if !tls12Names[want] { + t.Errorf("expected TLS 1.2 cipher %q in results", want) + } + } + + // All detected ciphers should be rated excellent (GCM + ECDHE only). + for _, c := range result.Ciphers { + if c.Rating != CipherRatingGood { + t.Errorf("cipher %q (%s) rated %q, want %q", c.Name, c.Version, c.Rating, CipherRatingGood) + } + } + + // Overall rating should be excellent. + if result.OverallRating != CipherRatingGood { + t.Errorf("OverallRating = %q, want %q", result.OverallRating, CipherRatingGood) + } + + // SupportedVersions should include both TLS 1.3 and TLS 1.2. + if len(result.SupportedVersions) < 2 { + t.Errorf("SupportedVersions = %v, want at least TLS 1.3 and TLS 1.2", result.SupportedVersions) + } +} + +func TestScanCipherSuites_EmptyHost(t *testing.T) { + t.Parallel() + _, err := ScanCipherSuites(context.Background(), ScanCipherSuitesInput{}) + if err == nil { + t.Fatal("expected error for empty host") + } +} + +func TestFormatCipherScanResult(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + result *CipherScanResult + wantStrings []string + }{ + { + name: "empty results — no output", + result: &CipherScanResult{ + Ciphers: nil, + }, + wantStrings: nil, // empty string, nothing to check + }, + { + name: "mixed ratings with kex subgroups", + result: &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3", "TLS 1.2"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", ID: tls.TLS_AES_128_GCM_SHA256, Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", ID: tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, Version: "TLS 1.2", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_RSA_WITH_AES_128_CBC_SHA", ID: tls.TLS_RSA_WITH_AES_128_CBC_SHA, Version: "TLS 1.2", KeyExchange: "RSA", Rating: CipherRatingWeak}, + }, + OverallRating: CipherRatingWeak, + }, + wantStrings: []string{ + "Cipher suites (3 supported)", + "TLS 1.3 (ECDHE):", + "TLS 1.2 (ECDHE):", + "TLS 1.2 (RSA, no forward secrecy):", + "[good]", + "[weak]", + "TLS_AES_128_GCM_SHA256", + "TLS_RSA_WITH_AES_128_CBC_SHA", + }, + }, + { + name: "single cipher", + result: &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + OverallRating: CipherRatingGood, + }, + wantStrings: []string{ + "Cipher suites (1 supported)", + "TLS 1.3 (ECDHE):", + "[good]", + }, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + output := FormatCipherScanResult(tt.result) + for _, want := range tt.wantStrings { + if !strings.Contains(output, want) { + t.Errorf("output missing %q\ngot:\n%s", want, output) + } + } + }) + } +} + +func TestFormatCipherRatingLine(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + scan *CipherScanResult + want string + }{ + { + name: "nil scan", + scan: nil, + want: "", + }, + { + name: "all good", + scan: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Rating: CipherRatingGood}, + {Rating: CipherRatingGood}, + }, + OverallRating: CipherRatingGood, + }, + want: "Ciphers: good (2 good, 0 weak)\n", + }, + { + name: "mixed", + scan: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Rating: CipherRatingGood}, + {Rating: CipherRatingWeak}, + }, + OverallRating: CipherRatingWeak, + }, + want: "Ciphers: weak (1 good, 1 weak)\n", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + got := FormatCipherRatingLine(tt.scan) + if got != tt.want { + t.Errorf("got %q, want %q", got, tt.want) + } + }) + } +} + +func TestDiagnoseCipherScan(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + result *CipherScanResult + wantChecks int + wantDetail string // substring in first diagnostic detail + }{ + { + name: "nil result", + result: nil, + wantChecks: 0, + }, + { + name: "all good — no diagnostics", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, + }, + }, + wantChecks: 0, + }, + { + name: "weak ciphers present", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, + {Name: "TLS_RSA_WITH_AES_128_CBC_SHA", Version: "TLS 1.2", Rating: CipherRatingWeak}, + {Name: "TLS_RSA_WITH_3DES_EDE_CBC_SHA", Version: "TLS 1.0", Rating: CipherRatingWeak}, + }, + }, + wantChecks: 1, + wantDetail: "server accepts 2 weak cipher suite(s) that should be disabled", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + diags := DiagnoseCipherScan(tt.result) + if len(diags) != tt.wantChecks { + t.Fatalf("got %d diagnostics, want %d: %+v", len(diags), tt.wantChecks, diags) + } + if tt.wantChecks > 0 { + if diags[0].Check != "weak-cipher" { + t.Errorf("Check = %q, want %q", diags[0].Check, "weak-cipher") + } + if !strings.Contains(diags[0].Detail, tt.wantDetail) { + t.Errorf("Detail = %q, want substring %q", diags[0].Detail, tt.wantDetail) + } + } + }) + } +} + func TestConnectTLS_CRL_DuplicateLeafInChain(t *testing.T) { t.Parallel() @@ -1283,3 +1654,550 @@ func TestConnectTLS_CRL_DuplicateLeafInChain(t *testing.T) { t.Errorf("CRL.Detail = %q, want substring %q", result.CRL.Detail, revokedSerial.Text(16)) } } + +func TestBuildClientHello(t *testing.T) { + t.Parallel() + + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: "example.com", + cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 + groupID: tls.X25519, + }) + if err != nil { + t.Fatalf("buildClientHelloMsg failed: %v", err) + } + + // Handshake type must be ClientHello (0x01). + if msg[0] != 0x01 { + t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) + } + + // Handshake length (3 bytes, big-endian) must match actual body length. + handshakeLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) + if handshakeLen != len(msg)-4 { + t.Errorf("handshake length = %d, want %d", handshakeLen, len(msg)-4) + } + + // Legacy version at body[0:2] must be TLS 1.2 (0x0303). + if msg[4] != 0x03 || msg[5] != 0x03 { + t.Errorf("legacy version = 0x%02x%02x, want 0x0303", msg[4], msg[5]) + } + + // Client random is 32 bytes starting at body[2]. + // Session ID length at body[34], session ID follows. + sessionIDLen := int(msg[4+34]) + if sessionIDLen != 32 { + t.Errorf("session ID length = %d, want 32", sessionIDLen) + } + + // Cipher suite list starts after session ID. + csOffset := 4 + 35 + sessionIDLen + csListLen := int(msg[csOffset])<<8 | int(msg[csOffset+1]) + if csListLen != 2 { + t.Errorf("cipher suite list length = %d, want 2 (single cipher)", csListLen) + } + csID := uint16(msg[csOffset+2])<<8 | uint16(msg[csOffset+3]) + if csID != 0x1301 { + t.Errorf("cipher suite = 0x%04x, want 0x1301", csID) + } +} + +func TestBuildClientHello_WithALPN(t *testing.T) { + t.Parallel() + + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: "example.com", + cipherSuite: 0x1301, + groupID: tls.X25519, + alpn: []string{"h3"}, + quic: true, + }) + if err != nil { + t.Fatalf("buildClientHelloMsg with ALPN failed: %v", err) + } + + // Message must contain the ALPN extension (type 0x0010) with "h3". + if !containsBytes(msg, []byte("h3")) { + t.Error("ClientHello missing ALPN 'h3'") + } + + // Must also be a valid handshake message. + if msg[0] != 0x01 { + t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) + } +} + +func TestParseServerHello(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + data []byte + wantCipher uint16 + wantVersion uint16 + wantErr string + }{ + { + name: "valid TLS 1.3 ServerHello", + data: buildTestServerHello(0x1301, 0x0304), + wantCipher: 0x1301, + wantVersion: 0x0304, + }, + { + name: "valid TLS 1.2 ServerHello (no supported_versions ext)", + data: buildTestServerHello12(0xc02f), + wantCipher: 0xc02f, + wantVersion: 0x0303, + }, + { + name: "truncated input", + data: []byte{0x02, 0x00}, + wantErr: "too short", + }, + { + name: "wrong handshake type", + data: append([]byte{0x0b, 0x00, 0x00, 0x04}, make([]byte, 4)...), + wantErr: "unexpected handshake type", + }, + { + name: "HelloRetryRequest (HRR sentinel random)", + data: buildTestServerHelloHRR(0x1301), + wantErr: "HelloRetryRequest", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + result, err := parseServerHello(tt.data) + if tt.wantErr != "" { + if err == nil { + t.Fatalf("expected error containing %q, got nil", tt.wantErr) + } + if !strings.Contains(err.Error(), tt.wantErr) { + t.Errorf("error = %q, want substring %q", err, tt.wantErr) + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if result.cipherSuite != tt.wantCipher { + t.Errorf("cipherSuite = 0x%04x, want 0x%04x", result.cipherSuite, tt.wantCipher) + } + if result.version != tt.wantVersion { + t.Errorf("version = 0x%04x, want 0x%04x", result.version, tt.wantVersion) + } + }) + } +} + +func TestGenerateKeyShare(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + groupID tls.CurveID + wantLen int + }{ + {"X25519", tls.X25519, 32}, + {"P-256", tls.CurveP256, 65}, + {"P-384", tls.CurveP384, 97}, + {"P-521", tls.CurveP521, 133}, + {"X25519MLKEM768", tls.X25519MLKEM768, 1184 + 32}, // ML-KEM-768 encap key + X25519 + {"SecP256r1MLKEM768", tls.SecP256r1MLKEM768, 65 + 1184}, // P-256 + ML-KEM-768 + {"SecP384r1MLKEM1024", tls.SecP384r1MLKEM1024, 97 + 1568}, // P-384 + ML-KEM-1024 + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + data, err := generateKeyShare(tt.groupID) + if err != nil { + t.Fatalf("generateKeyShare(%s) failed: %v", tt.name, err) + } + if len(data) != tt.wantLen { + t.Errorf("key share length = %d, want %d", len(data), tt.wantLen) + } + }) + } +} + +func TestGenerateKeyShare_UnsupportedGroup(t *testing.T) { + t.Parallel() + _, err := generateKeyShare(tls.CurveID(0xFFFF)) + if err == nil { + t.Fatal("expected error for unsupported group") + } +} + +func TestDeriveQUICInitialKeys(t *testing.T) { + t.Parallel() + + // RFC 9001 Appendix A test vectors. + dcid := hexDecode(t, "8394c8f03e515708") + + client, server, err := deriveQUICInitialKeys(dcid) + if err != nil { + t.Fatalf("deriveQUICInitialKeys failed: %v", err) + } + + // Client keys. + assertHex(t, "client key", client.key, "1f369613dd76d5467730efcbe3b1a22d") + assertHex(t, "client iv", client.iv, "fa044b2f42a3fd3b46fb255c") + assertHex(t, "client hp", client.hp, "9f50449e04a0e810283a1e9933adedd2") + + // Server keys. + assertHex(t, "server key", server.key, "cf3a5331653c364c88f0f379b6067e37") + assertHex(t, "server iv", server.iv, "0ac1493ca1905853b0bba03e") + assertHex(t, "server hp", server.hp, "c206b8d9b9f0f37644430b490eeaa314") +} + +func TestBuildQUICInitialPacket(t *testing.T) { + t.Parallel() + + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: "example.com", + cipherSuite: 0x1301, + groupID: tls.X25519, + alpn: []string{"h3"}, + quic: true, + }) + if err != nil { + t.Fatalf("buildClientHelloMsg failed: %v", err) + } + + dcid := hexDecode(t, "0102030405060708") + scid := hexDecode(t, "0807060504030201") + + packet, err := buildQUICInitialPacket(quicInitialPacketInput{ + clientHello: msg, + dcid: dcid, + scid: scid, + }) + if err != nil { + t.Fatalf("buildQUICInitialPacket failed: %v", err) + } + + // Packet must be at least 1200 bytes (QUIC minimum datagram size). + if len(packet) < 1200 { + t.Errorf("packet length = %d, want >= 1200", len(packet)) + } + + // Version field (bytes 1-4 after header protection) should be QUIC v1 + // before header protection. We can't check after HP, but verify the packet + // is non-empty and has the long-header high bit set (after HP, bit may vary). + // The packet should at least be well-formed and non-trivially sized. + if len(packet) == 0 { + t.Fatal("empty packet") + } +} + +func TestProbeTLS13Cipher_Concurrent(t *testing.T) { + t.Parallel() + + // Verify that concurrent raw probes don't race. Each probe is fully + // isolated with its own TCP connection and packet — no shared state. + + ca := generateTestCA(t, "Raw Probe CA") + leaf := generateTestLeafCert(t, ca) + + tlsCert := tls.Certificate{ + Certificate: [][]byte{leaf.DER, ca.CertDER}, + PrivateKey: leaf.Key, + } + port := startTLSServerWithConfig(t, &tls.Config{ + Certificates: []tls.Certificate{tlsCert}, + }) + addr := net.JoinHostPort("127.0.0.1", port) + + ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) + defer cancel() + + // Run 50 concurrent probes against 3 different cipher suites. + var wg sync.WaitGroup + for i := range 50 { + wg.Add(1) + go func(idx int) { + defer wg.Done() + cipherID := tls13CipherSuites[idx%len(tls13CipherSuites)] + probeTLS13Cipher(ctx, addr, "127.0.0.1", cipherID) + }(i) + } + wg.Wait() + // If the race detector doesn't fire, the test passes. +} + +func TestScanCipherSuites_KeyExchanges(t *testing.T) { + t.Parallel() + + ca := generateTestCA(t, "KX Scan CA") + leaf := generateTestLeafCert(t, ca) + + tlsCert := tls.Certificate{ + Certificate: [][]byte{leaf.DER, ca.CertDER}, + PrivateKey: leaf.Key, + } + port := startTLSServerWithConfig(t, &tls.Config{ + Certificates: []tls.Certificate{tlsCert}, + }) + + ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) + defer cancel() + + result, err := ScanCipherSuites(ctx, ScanCipherSuitesInput{ + Host: "127.0.0.1", + Port: port, + Concurrency: 5, + }) + if err != nil { + t.Fatalf("ScanCipherSuites failed: %v", err) + } + + // Go's TLS server should accept at least X25519 and P-256. + if len(result.KeyExchanges) == 0 { + t.Fatal("no key exchange groups detected") + } + + names := make(map[string]bool) + for _, kx := range result.KeyExchanges { + names[kx.Name] = true + // Verify PostQuantum flag is set correctly. + if kx.Name == "X25519MLKEM768" || kx.Name == "SecP256r1MLKEM768" || kx.Name == "SecP384r1MLKEM1024" { + if !kx.PostQuantum { + t.Errorf("key exchange %s should be PostQuantum", kx.Name) + } + } else if kx.PostQuantum { + t.Errorf("key exchange %s should not be PostQuantum", kx.Name) + } + } + + if !names["X25519"] { + t.Error("expected X25519 in key exchange results") + } +} + +func TestFormatCipherScanResult_QUICAndKeyExchanges(t *testing.T) { + t.Parallel() + + result := &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + QUICProbed: true, + QUICCiphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_AES_256_GCM_SHA384", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + KeyExchanges: []KeyExchangeProbeResult{ + {Name: "X25519MLKEM768", ID: 4588, PostQuantum: true}, + {Name: "X25519", ID: 29}, + {Name: "P-256", ID: 23}, + }, + OverallRating: CipherRatingGood, + } + + output := FormatCipherScanResult(result) + + for _, want := range []string{ + "Cipher suites (1 supported)", + "QUIC cipher suites (2 supported)", + "Key exchange groups (3 supported, forward secrecy)", + "X25519MLKEM768 (post-quantum)", + "X25519\n", + "P-256\n", + } { + if !strings.Contains(output, want) { + t.Errorf("output missing %q\ngot:\n%s", want, output) + } + } +} + +func TestFormatCipherScanResult_QUICNotSupported(t *testing.T) { + t.Parallel() + + result := &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + QUICProbed: true, + QUICCiphers: nil, + OverallRating: CipherRatingGood, + } + + output := FormatCipherScanResult(result) + + if !strings.Contains(output, "QUIC: not supported") { + t.Errorf("expected QUIC not supported line\ngot:\n%s", output) + } +} + +func TestIsPQKeyExchange(t *testing.T) { + t.Parallel() + + tests := []struct { + id tls.CurveID + want bool + }{ + {tls.X25519MLKEM768, true}, + {tls.SecP256r1MLKEM768, true}, + {tls.SecP384r1MLKEM1024, true}, + {tls.X25519, false}, + {tls.CurveP256, false}, + {tls.CurveP384, false}, + {tls.CurveP521, false}, + } + + for _, tt := range tests { + if got := isPQKeyExchange(tt.id); got != tt.want { + t.Errorf("isPQKeyExchange(%s) = %v, want %v", tt.id, got, tt.want) + } + } +} + +func TestQUICVarint(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + val uint64 + want []byte + }{ + {"zero", 0, []byte{0x00}}, + {"one byte max", 63, []byte{0x3f}}, + {"two byte min", 64, []byte{0x40, 0x40}}, + {"two byte max", 16383, []byte{0x7f, 0xff}}, + {"four byte min", 16384, []byte{0x80, 0x00, 0x40, 0x00}}, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + got := appendQUICVarint(nil, tt.val) + if len(got) != len(tt.want) { + t.Fatalf("length = %d, want %d", len(got), len(tt.want)) + } + for i := range got { + if got[i] != tt.want[i] { + t.Errorf("byte[%d] = 0x%02x, want 0x%02x", i, got[i], tt.want[i]) + } + } + + // Round-trip through decode. + decoded, n := decodeQUICVarint(got) + if decoded != tt.val { + t.Errorf("decode = %d, want %d", decoded, tt.val) + } + if n != len(got) { + t.Errorf("decode consumed %d bytes, want %d", n, len(got)) + } + }) + } +} + +// ---------- test helpers ---------- + +// buildTestServerHello constructs a minimal TLS 1.3 ServerHello handshake message +// with the given cipher suite and a supported_versions extension. +func buildTestServerHello(cipherSuite uint16, version uint16) []byte { + // ServerHello body: version(2) + random(32) + session_id(1+32) + cipher(2) + compression(1) + extensions + var body []byte + body = append(body, 0x03, 0x03) // legacy version TLS 1.2 + body = append(body, make([]byte, 32)...) // random + body = append(body, 32) // session ID length + body = append(body, make([]byte, 32)...) // session ID + body = appendUint16(body, cipherSuite) + body = append(body, 0x00) // compression: null + + // Extensions: supported_versions. + var exts []byte + exts = appendUint16(exts, 0x002b) // supported_versions + exts = appendUint16(exts, 2) // length + exts = appendUint16(exts, version) + body = appendUint16(body, uint16(len(exts))) + body = append(body, exts...) + + msg := []byte{0x02} // ServerHello + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg +} + +// buildTestServerHelloHRR constructs a ServerHello with the HelloRetryRequest +// sentinel random value (RFC 8446 §4.1.3), indicating the server doesn't +// support the offered key exchange group. +func buildTestServerHelloHRR(cipherSuite uint16) []byte { + var body []byte + body = append(body, 0x03, 0x03) // legacy version TLS 1.2 + // HRR sentinel random (RFC 8446 §4.1.3). + body = append(body, + 0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11, + 0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91, + 0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E, + 0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C, + ) + body = append(body, 32) // session ID length + body = append(body, make([]byte, 32)...) // session ID + body = appendUint16(body, cipherSuite) + body = append(body, 0x00) // compression: null + + // Extensions: supported_versions with TLS 1.3. + var exts []byte + exts = appendUint16(exts, 0x002b) // supported_versions + exts = appendUint16(exts, 2) // length + exts = appendUint16(exts, 0x0304) // TLS 1.3 + body = appendUint16(body, uint16(len(exts))) + body = append(body, exts...) + + msg := []byte{0x02} // ServerHello + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg +} + +// buildTestServerHello12 constructs a minimal TLS 1.2 ServerHello (no supported_versions ext). +func buildTestServerHello12(cipherSuite uint16) []byte { + var body []byte + body = append(body, 0x03, 0x03) // legacy version TLS 1.2 + body = append(body, make([]byte, 32)...) // random + body = append(body, 32) // session ID length + body = append(body, make([]byte, 32)...) // session ID + body = appendUint16(body, cipherSuite) + body = append(body, 0x00) // compression: null + + msg := []byte{0x02} // ServerHello + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg +} + +// containsBytes reports whether b contains the subslice sub. +func containsBytes(b, sub []byte) bool { + for i := range len(b) - len(sub) + 1 { + if string(b[i:i+len(sub)]) == string(sub) { + return true + } + } + return false +} + +// hexDecode decodes a hex string, failing the test on error. +func hexDecode(t *testing.T, s string) []byte { + t.Helper() + b, err := hex.DecodeString(s) + if err != nil { + t.Fatalf("hex decode %q: %v", s, err) + } + return b +} + +// assertHex compares a byte slice to an expected hex string. +func assertHex(t *testing.T, name string, got []byte, wantHex string) { + t.Helper() + gotHex := hex.EncodeToString(got) + if gotHex != wantHex { + t.Errorf("%s = %s, want %s", name, gotHex, wantHex) + } +} diff --git a/go.mod b/go.mod index 5453453..77120d5 100644 --- a/go.mod +++ b/go.mod @@ -5,6 +5,7 @@ go 1.26 require ( github.com/breml/rootcerts v0.3.4 github.com/jmoiron/sqlx v1.4.0 + github.com/mattn/go-isatty v0.0.20 github.com/pavlo-v-chernykh/keystore-go/v4 v4.5.0 github.com/smallstep/pkcs7 v0.2.1 github.com/spf13/cobra v1.10.2 @@ -22,7 +23,6 @@ require ( github.com/inconshreveable/mousetrap v1.1.0 // indirect github.com/kr/pretty v0.1.0 // indirect github.com/kr/text v0.2.0 // indirect - github.com/mattn/go-isatty v0.0.20 // indirect github.com/ncruces/go-strftime v1.0.0 // indirect github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect golang.org/x/exp v0.0.0-20260218203240-3dfff04db8fa // indirect diff --git a/quicprobe.go b/quicprobe.go new file mode 100644 index 0000000..c1a205e --- /dev/null +++ b/quicprobe.go @@ -0,0 +1,523 @@ +package certkit + +// This file implements a raw QUIC v1 Initial packet prober for detecting +// TLS 1.3 cipher suites over UDP (port 443). It wraps the same ClientHello +// from tls13probe.go in an encrypted QUIC Initial packet per RFC 9001. +// +// QUIC Initial packets are encrypted with keys derived from the client's +// chosen Destination Connection ID using HKDF + AES-128-GCM. This is not +// for security (the DCID is sent in plaintext) but for protocol correctness. + +import ( + "context" + "crypto/aes" + "crypto/cipher" + "crypto/hkdf" + "crypto/rand" + "crypto/sha256" + "crypto/tls" + "encoding/binary" + "fmt" + "io" + "net" +) + +// quicV1InitialSalt is the salt used to derive Initial keys for QUIC v1 +// connections (RFC 9001 §5.2). +var quicV1InitialSalt = []byte{ + 0x38, 0x76, 0x2c, 0xf7, 0xf5, 0x59, 0x34, 0xb3, + 0x4d, 0x17, 0x9a, 0xe6, 0xa4, 0xc8, 0x0c, 0xad, + 0xcc, 0xbb, 0x7f, 0x0a, +} + +// quicInitialKeys holds the derived encryption keys for QUIC Initial packets. +type quicInitialKeys struct { + key []byte // AES-128 key (16 bytes) + iv []byte // AES-128-GCM IV/nonce (12 bytes) + hp []byte // Header protection key (16 bytes) +} + +// deriveQUICInitialKeys derives the client and server Initial keys from +// the Destination Connection ID per RFC 9001 §5.2. +func deriveQUICInitialKeys(dcid []byte) (client, server quicInitialKeys, err error) { + initialSecret, err := hkdf.Extract(sha256.New, dcid, quicV1InitialSalt) + if err != nil { + return client, server, fmt.Errorf("extracting initial secret: %w", err) + } + + clientSecret, err := hkdfExpandLabel(initialSecret, "client in", 32) + if err != nil { + return client, server, fmt.Errorf("deriving client secret: %w", err) + } + client, err = deriveTrafficKeys(clientSecret) + if err != nil { + return client, server, fmt.Errorf("deriving client keys: %w", err) + } + + serverSecret, err := hkdfExpandLabel(initialSecret, "server in", 32) + if err != nil { + return client, server, fmt.Errorf("deriving server secret: %w", err) + } + server, err = deriveTrafficKeys(serverSecret) + if err != nil { + return client, server, fmt.Errorf("deriving server keys: %w", err) + } + + return client, server, nil +} + +// deriveTrafficKeys derives key, IV, and HP key from a traffic secret. +func deriveTrafficKeys(secret []byte) (quicInitialKeys, error) { + key, err := hkdfExpandLabel(secret, "quic key", 16) + if err != nil { + return quicInitialKeys{}, err + } + iv, err := hkdfExpandLabel(secret, "quic iv", 12) + if err != nil { + return quicInitialKeys{}, err + } + hp, err := hkdfExpandLabel(secret, "quic hp", 16) + if err != nil { + return quicInitialKeys{}, err + } + return quicInitialKeys{key: key, iv: iv, hp: hp}, nil +} + +// hkdfExpandLabel implements TLS 1.3 HKDF-Expand-Label (RFC 8446 §7.1). +// The label is prefixed with "tls13 " as required by the spec. +func hkdfExpandLabel(secret []byte, label string, length int) ([]byte, error) { + fullLabel := "tls13 " + label + + // Build HkdfLabel struct: uint16 length + opaque label<7..255> + opaque context<0..255> + var info []byte + info = appendUint16(info, uint16(length)) + info = append(info, byte(len(fullLabel))) + info = append(info, []byte(fullLabel)...) + info = append(info, 0) // empty context + + return hkdf.Expand(sha256.New, secret, string(info), length) +} + +// quicInitialPacketInput contains parameters for building a QUIC Initial packet. +type quicInitialPacketInput struct { + clientHello []byte // raw ClientHello handshake message (no TLS record header) + dcid []byte // Destination Connection ID + scid []byte // Source Connection ID +} + +// buildQUICInitialPacket constructs an encrypted QUIC v1 Initial packet +// containing the ClientHello in a CRYPTO frame. The packet is padded to +// the 1200-byte minimum required by RFC 9000 §14.1. +func buildQUICInitialPacket(input quicInitialPacketInput) ([]byte, error) { + clientKeys, _, err := deriveQUICInitialKeys(input.dcid) + if err != nil { + return nil, fmt.Errorf("deriving QUIC keys: %w", err) + } + + // Build CRYPTO frame: type(1) + offset(var) + length(var) + data + var cryptoFrame []byte + cryptoFrame = append(cryptoFrame, 0x06) // CRYPTO frame type + cryptoFrame = append(cryptoFrame, 0x00) // offset = 0 (single-byte varint) + cryptoFrame = appendQUICVarint(cryptoFrame, uint64(len(input.clientHello))) + cryptoFrame = append(cryptoFrame, input.clientHello...) + + // Build Initial packet header (Long Header form). + // First byte: 1 (long) | 1 (fixed) | 00 (Initial) | 00 (reserved) | 00 (PN length - 1 = 0, meaning 1 byte) + // We use 4-byte packet number for simplicity (PN length bits = 11 = 3, meaning 4 bytes). + firstByte := byte(0xc0) // Long Header | Fixed bit | Initial type + firstByte |= 0x03 // Packet number length: 4 bytes (value = 3 means 4 bytes) + + var header []byte + header = append(header, firstByte) + header = append(header, 0x00, 0x00, 0x00, 0x01) // Version: QUIC v1 + header = append(header, byte(len(input.dcid))) + header = append(header, input.dcid...) + header = append(header, byte(len(input.scid))) + header = append(header, input.scid...) + header = append(header, 0x00) // Token length: 0 (no token for Initial) + + // Payload = CRYPTO frame + PADDING frames (0x00 bytes). + // We need to pad the total UDP datagram to at least 1200 bytes. + // Total = header + length_field(2 varint bytes) + payload + AEAD_tag(16) + packetNumberBytes := 4 + aeadOverhead := 16 + payloadWithPN := packetNumberBytes + len(cryptoFrame) + + // Calculate minimum payload size for 1200-byte datagram. + // header + 2 (length varint) + payloadWithPN + aeadOverhead + padding >= 1200 + headerWithLength := len(header) + 2 // 2 bytes for length varint (enough for < 16384) + minPayloadWithPN := 1200 - headerWithLength - aeadOverhead + if minPayloadWithPN > payloadWithPN { + padding := make([]byte, minPayloadWithPN-payloadWithPN) // PADDING frames are 0x00 + cryptoFrame = append(cryptoFrame, padding...) + payloadWithPN = minPayloadWithPN + } + + // Encode the length field (payload + packet number + AEAD tag) as a 2-byte varint. + lengthVal := uint64(payloadWithPN + aeadOverhead) + header = appendQUICVarint2(header, lengthVal) + + // Packet number (4 bytes, value = 0 for first packet). + pnOffset := len(header) + header = append(header, 0x00, 0x00, 0x00, 0x00) // PN = 0 + + // Encrypt payload with AES-128-GCM. + block, err := aes.NewCipher(clientKeys.key) + if err != nil { + return nil, fmt.Errorf("creating AES cipher: %w", err) + } + gcm, err := cipher.NewGCM(block) + if err != nil { + return nil, fmt.Errorf("creating GCM: %w", err) + } + + // Nonce = IV XOR packet number (left-padded to 12 bytes). + nonce := make([]byte, 12) + copy(nonce, clientKeys.iv) + // PN = 0, so nonce = IV (XOR with 0 is identity). + + // Plaintext = CRYPTO frame (+ padding). + ciphertext := gcm.Seal(nil, nonce, cryptoFrame, header) + + // Assemble the packet before header protection. + packet := append(header, ciphertext...) + + // Apply header protection (RFC 9001 §5.4.1). + // Sample starts 4 bytes after the start of the packet number field. + sampleOffset := pnOffset + 4 + if sampleOffset+16 > len(packet) { + return nil, fmt.Errorf("packet too short for header protection sample") + } + sample := packet[sampleOffset : sampleOffset+16] + + hpBlock, err := aes.NewCipher(clientKeys.hp) + if err != nil { + return nil, fmt.Errorf("creating HP cipher: %w", err) + } + mask := make([]byte, aes.BlockSize) + hpBlock.Encrypt(mask, sample) + + // Mask the first byte (Long Header: lower 4 bits). + packet[0] ^= mask[0] & 0x0f + + // Mask the packet number bytes. + for i := range packetNumberBytes { + packet[pnOffset+i] ^= mask[1+i] + } + + return packet, nil +} + +// parseQUICInitialResponse decrypts a QUIC Initial response packet and +// extracts the ServerHello from the CRYPTO frame. +func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serverHelloResult, error) { + if len(packet) < 5 { + return nil, fmt.Errorf("QUIC packet too short: %d bytes", len(packet)) + } + + // Check it's a Long Header Initial packet. + firstByte := packet[0] + if firstByte&0x80 == 0 { + return nil, fmt.Errorf("not a Long Header packet") + } + + // Remove header protection first. + // Parse enough of the header to find packet number offset. + pos := 1 + // Version (4 bytes). + if pos+4 > len(packet) { + return nil, fmt.Errorf("packet truncated at version") + } + pos += 4 + + // DCID. + if pos+1 > len(packet) { + return nil, fmt.Errorf("packet truncated at DCID length") + } + dcidLen := int(packet[pos]) + pos += 1 + dcidLen + + // SCID. + if pos+1 > len(packet) { + return nil, fmt.Errorf("packet truncated at SCID length") + } + scidLen := int(packet[pos]) + pos += 1 + scidLen + + // Token length (varint). + if pos >= len(packet) { + return nil, fmt.Errorf("packet truncated at token length") + } + tokenLen, tokenVarLen := decodeQUICVarint(packet[pos:]) + pos += tokenVarLen + int(tokenLen) + + // Payload length (varint) — covers packet number + encrypted data + AEAD tag. + // Must be kept to avoid decrypting coalesced packets (Initial + Handshake). + if pos >= len(packet) { + return nil, fmt.Errorf("packet truncated at payload length") + } + payloadLen, payloadVarLen := decodeQUICVarint(packet[pos:]) + pos += payloadVarLen + + pnOffset := pos + payloadEnd := pnOffset + int(payloadLen) + + // We need the sample for header protection removal. + // The PN length is encoded in the first byte (lower 2 bits after unmasking). + // But we need to unmask it first. Sample is at pnOffset + 4. + sampleOffset := pnOffset + 4 + if sampleOffset+16 > len(packet) { + return nil, fmt.Errorf("packet too short for HP sample: need %d, have %d", sampleOffset+16, len(packet)) + } + sample := packet[sampleOffset : sampleOffset+16] + + hpBlock, err := aes.NewCipher(serverKeys.hp) + if err != nil { + return nil, fmt.Errorf("creating HP cipher: %w", err) + } + mask := make([]byte, aes.BlockSize) + hpBlock.Encrypt(mask, sample) + + // Unmask first byte to get packet number length. + packet[0] ^= mask[0] & 0x0f + pnLen := int(packet[0]&0x03) + 1 + + // Unmask packet number. + for i := range pnLen { + packet[pnOffset+i] ^= mask[1+i] + } + + // The header is everything up to and including the packet number. + headerEnd := pnOffset + pnLen + if headerEnd >= len(packet) { + return nil, fmt.Errorf("packet truncated at packet number") + } + + // Decrypt the payload. + ciphertextStart := headerEnd + associatedData := packet[:headerEnd] + + block, err := aes.NewCipher(serverKeys.key) + if err != nil { + return nil, fmt.Errorf("creating AES cipher: %w", err) + } + gcm, err := cipher.NewGCM(block) + if err != nil { + return nil, fmt.Errorf("creating GCM: %w", err) + } + + // Reconstruct nonce: IV XOR packet_number (left-padded). + nonce := make([]byte, 12) + copy(nonce, serverKeys.iv) + // XOR the packet number into the rightmost bytes. + pnBytes := packet[pnOffset:headerEnd] + for i, b := range pnBytes { + nonce[12-pnLen+i] ^= b + } + + if payloadEnd > len(packet) { + payloadEnd = len(packet) + } + plaintext, err := gcm.Open(nil, nonce, packet[ciphertextStart:payloadEnd], associatedData) + if err != nil { + return nil, fmt.Errorf("decrypting QUIC payload: %w", err) + } + + // Find the CRYPTO frame in the plaintext. + // Frame type 0x06 = CRYPTO, followed by offset (varint) + length (varint) + data. + fpos := 0 + for fpos < len(plaintext) { + frameType := plaintext[fpos] + if frameType == 0x00 { + // PADDING frame — skip. + fpos++ + continue + } + if frameType == 0x01 { + // PING frame — skip. + fpos++ + continue + } + if frameType == 0x02 || frameType == 0x03 { + // ACK frame (RFC 9000 §19.3): parse and skip. + fpos++ + _, varLen := decodeQUICVarint(plaintext[fpos:]) // Largest Acknowledged + fpos += varLen + _, varLen = decodeQUICVarint(plaintext[fpos:]) // ACK Delay + fpos += varLen + rangeCount, varLen := decodeQUICVarint(plaintext[fpos:]) // ACK Range Count + fpos += varLen + _, varLen = decodeQUICVarint(plaintext[fpos:]) // First ACK Range + fpos += varLen + for range rangeCount { + _, varLen = decodeQUICVarint(plaintext[fpos:]) // Gap + fpos += varLen + _, varLen = decodeQUICVarint(plaintext[fpos:]) // ACK Range Length + fpos += varLen + } + if frameType == 0x03 { + // ACK_ECN has 3 additional varints. + _, varLen = decodeQUICVarint(plaintext[fpos:]) + fpos += varLen + _, varLen = decodeQUICVarint(plaintext[fpos:]) + fpos += varLen + _, varLen = decodeQUICVarint(plaintext[fpos:]) + fpos += varLen + } + continue + } + if frameType != 0x06 { + // Unknown or unhandled frame type. + break + } + + // CRYPTO frame. + fpos++ // skip frame type + _, varLen := decodeQUICVarint(plaintext[fpos:]) + fpos += varLen // skip offset + + dataLen, varLen := decodeQUICVarint(plaintext[fpos:]) + fpos += varLen + + if fpos+int(dataLen) > len(plaintext) { + return nil, fmt.Errorf("CRYPTO frame data truncated") + } + cryptoData := plaintext[fpos : fpos+int(dataLen)] + + // The crypto data is a TLS handshake message (ServerHello). + return parseServerHello(cryptoData) + } + + return nil, fmt.Errorf("no CRYPTO frame found in QUIC Initial response") +} + +// probeQUICCipher sends a QUIC Initial packet to UDP 443 with a single +// cipher suite and returns true if the server accepts it. +func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint16) bool { + // Generate random connection IDs. + dcid := make([]byte, 8) + scid := make([]byte, 8) + if _, err := io.ReadFull(rand.Reader, dcid); err != nil { + return false + } + if _, err := io.ReadFull(rand.Reader, scid); err != nil { + return false + } + + // Build the ClientHello (without TLS record header — QUIC uses CRYPTO frames). + // QUIC requires ALPN ("h3"), quic_transport_parameters, and an empty session ID + // (RFC 9001 §8.4). + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: serverName, + cipherSuite: cipherID, + groupID: tls.X25519, + alpn: []string{"h3"}, + quic: true, + quicSCID: scid, + }) + if err != nil { + return false + } + + // Build the encrypted QUIC Initial packet. + packet, err := buildQUICInitialPacket(quicInitialPacketInput{ + clientHello: msg, + dcid: dcid, + scid: scid, + }) + if err != nil { + return false + } + + // Send via UDP. + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "udp", addr) + if err != nil { + return false + } + defer func() { _ = conn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = conn.SetDeadline(deadline) + } + + if _, err := conn.Write(packet); err != nil { + return false + } + + // Read response. QUIC Initial responses can be up to ~1400 bytes. + buf := make([]byte, 4096) + n, err := conn.Read(buf) + if err != nil { + return false + } + response := buf[:n] + + // Derive server keys for decryption (using our DCID). + _, serverKeys, err := deriveQUICInitialKeys(dcid) + if err != nil { + return false + } + + result, err := parseQUICInitialResponse(response, serverKeys) + if err != nil { + return false + } + + return result.version == tls.VersionTLS13 && result.cipherSuite == cipherID +} + +// ---------- QUIC varint helpers ---------- + +// appendQUICVarint appends a QUIC variable-length integer (RFC 9000 §16). +func appendQUICVarint(b []byte, v uint64) []byte { + switch { + case v < 64: + return append(b, byte(v)) + case v < 16384: + return append(b, byte(0x40|v>>8), byte(v)) + case v < 1073741824: + var buf [4]byte + binary.BigEndian.PutUint32(buf[:], uint32(v)|0x80000000) + return append(b, buf[:]...) + default: + var buf [8]byte + binary.BigEndian.PutUint64(buf[:], v|0xc000000000000000) + return append(b, buf[:]...) + } +} + +// appendQUICVarint2 appends a 2-byte QUIC varint (for values < 16384). +func appendQUICVarint2(b []byte, v uint64) []byte { + return append(b, byte(0x40|v>>8), byte(v)) +} + +// decodeQUICVarint decodes a QUIC variable-length integer and returns +// the value and the number of bytes consumed. +func decodeQUICVarint(data []byte) (uint64, int) { + if len(data) == 0 { + return 0, 0 + } + prefix := data[0] >> 6 + length := 1 << prefix + + if len(data) < length { + return 0, 0 + } + + switch length { + case 1: + return uint64(data[0] & 0x3f), 1 + case 2: + v := binary.BigEndian.Uint16(data[:2]) + return uint64(v & 0x3fff), 2 + case 4: + v := binary.BigEndian.Uint32(data[:4]) + return uint64(v & 0x3fffffff), 4 + case 8: + v := binary.BigEndian.Uint64(data[:8]) + return v & 0x3fffffffffffffff, 8 + default: + return 0, 0 + } +} diff --git a/testhelpers_test.go b/testhelpers_test.go index 7209778..2ef5455 100644 --- a/testhelpers_test.go +++ b/testhelpers_test.go @@ -431,3 +431,38 @@ func startTLSServer(t *testing.T, certChain [][]byte, key *ecdsa.PrivateKey) str } return port } + +// startTLSServerWithConfig starts a TLS server with the given tls.Config. +// The config must already have Certificates set. Returns the listener port. +// The server is stopped via t.Cleanup. +func startTLSServerWithConfig(t *testing.T, config *tls.Config) string { + t.Helper() + listener, err := tls.Listen("tcp", "127.0.0.1:0", config) + if err != nil { + t.Fatal(err) + } + t.Cleanup(func() { _ = listener.Close() }) + + go func() { + for { + conn, err := listener.Accept() + if err != nil { + return + } + if tlsConn, ok := conn.(*tls.Conn); ok { + if err := tlsConn.Handshake(); err != nil { + slog.Debug("startTLSServerWithConfig: handshake error", "error", err) + } + } + if err := conn.Close(); err != nil { + slog.Debug("startTLSServerWithConfig: connection close error", "error", err) + } + } + }() + + _, port, err := net.SplitHostPort(listener.Addr().String()) + if err != nil { + t.Fatal(err) + } + return port +} diff --git a/tls13probe.go b/tls13probe.go new file mode 100644 index 0000000..0fda940 --- /dev/null +++ b/tls13probe.go @@ -0,0 +1,571 @@ +package certkit + +// This file implements a raw TLS 1.3 ClientHello prober that constructs +// minimal TLS handshake packets at the byte level. It replaces the linkname +// hack (tls13hack.go) which caused data races by mutating a process-global +// variable in crypto/tls. +// +// The prober sends a ClientHello offering a single cipher suite and/or +// key exchange group, reads the ServerHello, and checks what the server +// accepted. Each probe is fully isolated — no shared state, no races. + +import ( + "context" + "crypto/ecdh" + "crypto/mlkem" + "crypto/rand" + "crypto/tls" + "encoding/binary" + "errors" + "fmt" + "io" + "net" +) + +// tls13CipherSuites lists all TLS 1.3 cipher suites from RFC 8446. +var tls13CipherSuites = []uint16{ + 0x1301, // TLS_AES_128_GCM_SHA256 + 0x1302, // TLS_AES_256_GCM_SHA384 + 0x1303, // TLS_CHACHA20_POLY1305_SHA256 + 0x1304, // TLS_AES_128_CCM_SHA256 + 0x1305, // TLS_AES_128_CCM_8_SHA256 +} + +// keyExchangeGroups lists all key exchange groups to probe, ordered by +// preference (PQ hybrids first, then classical curves). +var keyExchangeGroups = []tls.CurveID{ + tls.X25519MLKEM768, + tls.SecP256r1MLKEM768, + tls.SecP384r1MLKEM1024, + tls.X25519, + tls.CurveP256, + tls.CurveP384, + tls.CurveP521, +} + +// clientHelloInput contains parameters for building a raw TLS 1.3 ClientHello. +type clientHelloInput struct { + serverName string + cipherSuite uint16 + groupID tls.CurveID + alpn []string // optional ALPN protocols (e.g. ["h3"] for QUIC) + quic bool // include quic_transport_parameters extension + quicSCID []byte // QUIC source connection ID (for initial_source_connection_id) +} + +// serverHelloResult contains the parsed fields from a ServerHello. +type serverHelloResult struct { + cipherSuite uint16 + version uint16 // from supported_versions extension, or legacy field +} + +// errAlertReceived is returned when the server responds with a TLS Alert +// instead of a ServerHello, indicating the cipher suite or group was rejected. +var errAlertReceived = errors.New("TLS alert received") + +// errHelloRetryRequest is returned when the server responds with a +// HelloRetryRequest instead of a real ServerHello. Per RFC 8446 §4.1.3, an HRR +// is a ServerHello with a specific synthetic random value. It means the server +// supports TLS 1.3 but not the offered key exchange group. +var errHelloRetryRequest = errors.New("HelloRetryRequest received (group not supported)") + +// hrrSentinel is the synthetic random value that distinguishes a +// HelloRetryRequest from a real ServerHello (RFC 8446 §4.1.3). +var hrrSentinel = [32]byte{ + 0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11, + 0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91, + 0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E, + 0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C, +} + +// KeyExchangeProbeResult describes a single key exchange group accepted by the server. +type KeyExchangeProbeResult struct { + // Name is the human-readable group name (e.g. "X25519", "X25519MLKEM768"). + Name string `json:"name"` + // ID is the TLS CurveID / NamedGroup identifier. + ID uint16 `json:"id"` + // PostQuantum is true for hybrid post-quantum key exchange mechanisms. + PostQuantum bool `json:"post_quantum,omitempty"` +} + +// buildClientHelloMsg constructs a minimal TLS 1.3 ClientHello handshake +// message (type + length + body) offering a single cipher suite and a single +// key exchange group. The returned bytes do NOT include the TLS record header; +// callers wrap them in a TLS record (TCP) or QUIC CRYPTO frame (UDP). +func buildClientHelloMsg(input clientHelloInput) ([]byte, error) { + keyShareData, err := generateKeyShare(input.groupID) + if err != nil { + return nil, fmt.Errorf("generating key share for group %s: %w", input.groupID, err) + } + + // Build extensions. + var exts []byte + exts = appendSNIExtension(exts, input.serverName) + exts = appendSupportedGroupsExtension(exts, input.groupID) + exts = appendSignatureAlgorithmsExtension(exts) + exts = appendKeyShareExtension(exts, input.groupID, keyShareData) + exts = appendSupportedVersionsExtension(exts) + exts = appendPSKKeyExchangeModesExtension(exts) + if len(input.alpn) > 0 { + exts = appendALPNExtension(exts, input.alpn) + } + if input.quic { + exts = appendQUICTransportParamsExtension(exts, input.quicSCID) + } + + // Build ClientHello body. + var body []byte + + // Legacy version: TLS 1.2 (required for TLS 1.3 compatibility). + body = append(body, 0x03, 0x03) + + // Client random (32 bytes). + random := make([]byte, 32) + if _, err := io.ReadFull(rand.Reader, random); err != nil { + return nil, fmt.Errorf("generating client random: %w", err) + } + body = append(body, random...) + + // Session ID: 32 random bytes for TLS-over-TCP middlebox compatibility + // (RFC 8446 §4.1.2). QUIC MUST use an empty session ID (RFC 9001 §8.4). + if input.quic { + body = append(body, 0x00) // empty legacy_session_id + } else { + sessionID := make([]byte, 32) + if _, err := io.ReadFull(rand.Reader, sessionID); err != nil { + return nil, fmt.Errorf("generating session ID: %w", err) + } + body = append(body, byte(len(sessionID))) + body = append(body, sessionID...) + } + + // Cipher suites: single cipher. + body = appendUint16(body, 2) + body = appendUint16(body, input.cipherSuite) + + // Compression methods: null only. + body = append(body, 1, 0) + + // Extensions. + body = appendUint16(body, uint16(len(exts))) + body = append(body, exts...) + + // Wrap in handshake header: type(1) + length(3) + body. + msg := []byte{0x01} // ClientHello + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + + return msg, nil +} + +// wrapTLSRecord wraps a handshake message in a TLS record header. +func wrapTLSRecord(handshakeMsg []byte) []byte { + record := make([]byte, 0, 5+len(handshakeMsg)) + record = append(record, 0x16) // ContentType: Handshake + record = append(record, 0x03, 0x01) // Record version: TLS 1.0 (compatibility) + record = appendUint16(record, uint16(len(handshakeMsg))) + record = append(record, handshakeMsg...) + return record +} + +// generateKeyShare produces an ephemeral key share for the given named group. +// The private key is discarded — we only need the server to accept our +// ClientHello, not to complete the full handshake. +func generateKeyShare(groupID tls.CurveID) ([]byte, error) { + switch groupID { + case tls.X25519: + key, err := ecdh.X25519().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + return key.PublicKey().Bytes(), nil + + case tls.CurveP256: + key, err := ecdh.P256().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + return key.PublicKey().Bytes(), nil + + case tls.CurveP384: + key, err := ecdh.P384().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + return key.PublicKey().Bytes(), nil + + case tls.CurveP521: + key, err := ecdh.P521().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + return key.PublicKey().Bytes(), nil + + case tls.X25519MLKEM768: + // X25519MLKEM768: ML-KEM-768 encapsulation key first, then X25519. + // See draft-ietf-tls-ecdhe-mlkem-02 §4.1 and Go crypto/tls/key_schedule.go:184. + dk, err := mlkem.GenerateKey768() + if err != nil { + return nil, err + } + x, err := ecdh.X25519().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + return append(dk.EncapsulationKey().Bytes(), x.PublicKey().Bytes()...), nil + + case tls.SecP256r1MLKEM768: + // SecP256r1MLKEM768: ECDH (P-256) first, then ML-KEM-768. + ec, err := ecdh.P256().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + dk, err := mlkem.GenerateKey768() + if err != nil { + return nil, err + } + return append(ec.PublicKey().Bytes(), dk.EncapsulationKey().Bytes()...), nil + + case tls.SecP384r1MLKEM1024: + // SecP384r1MLKEM1024: ECDH (P-384) first, then ML-KEM-1024. + ec, err := ecdh.P384().GenerateKey(rand.Reader) + if err != nil { + return nil, err + } + dk, err := mlkem.GenerateKey1024() + if err != nil { + return nil, err + } + return append(ec.PublicKey().Bytes(), dk.EncapsulationKey().Bytes()...), nil + + default: + return nil, fmt.Errorf("unsupported group: 0x%04x", uint16(groupID)) + } +} + +// readServerHello reads a TLS record from the connection and parses the +// ServerHello message. Returns errAlertReceived if the server sent a TLS Alert. +func readServerHello(r io.Reader) (*serverHelloResult, error) { + // Read TLS record header (5 bytes): type(1) + version(2) + length(2). + header := make([]byte, 5) + if _, err := io.ReadFull(r, header); err != nil { + return nil, fmt.Errorf("reading TLS record header: %w", err) + } + + contentType := header[0] + recordLen := binary.BigEndian.Uint16(header[3:5]) + + // TLS records are limited to 16384 bytes plus some overhead. + if recordLen > 16640 { + return nil, fmt.Errorf("TLS record too large: %d bytes", recordLen) + } + + payload := make([]byte, recordLen) + if _, err := io.ReadFull(r, payload); err != nil { + return nil, fmt.Errorf("reading TLS record payload: %w", err) + } + + // Alert record: the server rejected the cipher suite or group. + if contentType == 0x15 { + return nil, errAlertReceived + } + + if contentType != 0x16 { + return nil, fmt.Errorf("unexpected TLS content type: 0x%02x", contentType) + } + + return parseServerHello(payload) +} + +// parseServerHello extracts the cipher suite and negotiated TLS version +// from a ServerHello handshake message. +func parseServerHello(data []byte) (*serverHelloResult, error) { + if len(data) < 4 { + return nil, fmt.Errorf("handshake message too short: %d bytes", len(data)) + } + + handshakeType := data[0] + handshakeLen := int(data[1])<<16 | int(data[2])<<8 | int(data[3]) + + if handshakeType != 0x02 { + return nil, fmt.Errorf("unexpected handshake type: 0x%02x (expected ServerHello 0x02)", handshakeType) + } + + if len(data) < 4+handshakeLen { + return nil, fmt.Errorf("ServerHello truncated: need %d bytes, have %d", 4+handshakeLen, len(data)) + } + + body := data[4 : 4+handshakeLen] + + // ServerHello body: version(2) + random(32) + session_id_len(1) + ... + if len(body) < 35 { + return nil, fmt.Errorf("ServerHello body too short: %d bytes", len(body)) + } + + // Check for HelloRetryRequest (RFC 8446 §4.1.3): a ServerHello with the + // special synthetic random value is actually an HRR, meaning the server + // doesn't support the offered key exchange group. + var serverRandom [32]byte + copy(serverRandom[:], body[2:34]) + if serverRandom == hrrSentinel { + return nil, errHelloRetryRequest + } + + pos := 34 // skip version(2) + random(32) + + // Session ID. + sessionIDLen := int(body[pos]) + pos += 1 + sessionIDLen + + // Cipher suite (2 bytes). + if pos+2 > len(body) { + return nil, fmt.Errorf("ServerHello truncated at cipher suite") + } + cipherSuite := binary.BigEndian.Uint16(body[pos : pos+2]) + pos += 2 + + // Compression method (1 byte). + if pos+1 > len(body) { + return nil, fmt.Errorf("ServerHello truncated at compression method") + } + pos++ + + // Default version from legacy field. + version := binary.BigEndian.Uint16(body[0:2]) + + // Parse extensions to find supported_versions (0x002b). + if pos+2 <= len(body) { + extLen := int(binary.BigEndian.Uint16(body[pos : pos+2])) + pos += 2 + + extEnd := min(pos+extLen, len(body)) + + for pos+4 <= extEnd { + extType := binary.BigEndian.Uint16(body[pos : pos+2]) + extDataLen := int(binary.BigEndian.Uint16(body[pos+2 : pos+4])) + pos += 4 + + if pos+extDataLen > extEnd { + break + } + + // supported_versions in ServerHello contains a single 2-byte version. + if extType == 0x002b && extDataLen >= 2 { + version = binary.BigEndian.Uint16(body[pos : pos+2]) + } + + pos += extDataLen + } + } + + return &serverHelloResult{ + cipherSuite: cipherSuite, + version: version, + }, nil +} + +// probeTLS13Cipher attempts a raw TLS 1.3 ClientHello with a single cipher +// suite and returns true if the server accepts it. Each call is fully isolated +// with no shared state — safe for concurrent use from multiple goroutines. +func probeTLS13Cipher(ctx context.Context, addr, serverName string, cipherID uint16) bool { + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", addr) + if err != nil { + return false + } + defer func() { _ = conn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = conn.SetDeadline(deadline) + } + + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: serverName, + cipherSuite: cipherID, + groupID: tls.X25519, + }) + if err != nil { + return false + } + + if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { + return false + } + + result, err := readServerHello(conn) + if err != nil { + return false + } + + return result.version == tls.VersionTLS13 && result.cipherSuite == cipherID +} + +// probeKeyExchangeGroup attempts a raw TLS 1.3 ClientHello offering a single +// named group and returns true if the server selects it. Uses +// TLS_AES_128_GCM_SHA256 as the cipher since all TLS 1.3 servers must support it. +func probeKeyExchangeGroup(ctx context.Context, addr, serverName string, groupID tls.CurveID) bool { + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", addr) + if err != nil { + return false + } + defer func() { _ = conn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = conn.SetDeadline(deadline) + } + + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: serverName, + cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 + groupID: groupID, + }) + if err != nil { + return false + } + + if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { + return false + } + + result, err := readServerHello(conn) + if err != nil { + return false + } + + return result.version == tls.VersionTLS13 +} + +// isPQKeyExchange reports whether the given CurveID is a post-quantum hybrid mechanism. +func isPQKeyExchange(id tls.CurveID) bool { + switch id { + case tls.X25519MLKEM768, tls.SecP256r1MLKEM768, tls.SecP384r1MLKEM1024: + return true + default: + return false + } +} + +// ---------- byte-level helpers ---------- + +func appendUint16(b []byte, v uint16) []byte { + return append(b, byte(v>>8), byte(v)) +} + +func appendUint24(b []byte, v uint32) []byte { + return append(b, byte(v>>16), byte(v>>8), byte(v)) +} + +// appendSNIExtension appends a server_name extension (0x0000). +func appendSNIExtension(b []byte, serverName string) []byte { + if serverName == "" { + return b + } + name := []byte(serverName) + listLen := 1 + 2 + len(name) // type(1) + name_len(2) + name + + b = appendUint16(b, 0x0000) // extension type + b = appendUint16(b, uint16(2+listLen)) // extension data length + b = appendUint16(b, uint16(listLen)) // server name list length + b = append(b, 0x00) // name type: host_name + b = appendUint16(b, uint16(len(name))) + return append(b, name...) +} + +// appendSupportedGroupsExtension appends a supported_groups extension (0x000a). +func appendSupportedGroupsExtension(b []byte, groupID tls.CurveID) []byte { + b = appendUint16(b, 0x000a) // extension type + b = appendUint16(b, 4) // extension data length + b = appendUint16(b, 2) // group list length + return appendUint16(b, uint16(groupID)) +} + +// appendSignatureAlgorithmsExtension appends a signature_algorithms extension (0x000d). +func appendSignatureAlgorithmsExtension(b []byte) []byte { + b = appendUint16(b, 0x000d) // extension type + b = appendUint16(b, 8) // extension data length + b = appendUint16(b, 6) // algorithm list length (3 algorithms × 2 bytes) + b = appendUint16(b, 0x0403) // ecdsa_secp256r1_sha256 + b = appendUint16(b, 0x0804) // rsa_pss_rsae_sha256 + return appendUint16(b, 0x0401) // rsa_pkcs1_sha256 +} + +// appendKeyShareExtension appends a key_share extension (0x0033). +func appendKeyShareExtension(b []byte, groupID tls.CurveID, keyData []byte) []byte { + entryLen := 2 + 2 + len(keyData) // group(2) + key_len(2) + key_data + + b = appendUint16(b, 0x0033) // extension type + b = appendUint16(b, uint16(2+entryLen)) // extension data length + b = appendUint16(b, uint16(entryLen)) // client key shares length + b = appendUint16(b, uint16(groupID)) // named group + b = appendUint16(b, uint16(len(keyData))) + return append(b, keyData...) +} + +// appendSupportedVersionsExtension appends a supported_versions extension (0x002b) +// offering TLS 1.3 only. +func appendSupportedVersionsExtension(b []byte) []byte { + b = appendUint16(b, 0x002b) // extension type + b = appendUint16(b, 3) // extension data length + b = append(b, 2) // version list length (1 version × 2 bytes) + return appendUint16(b, 0x0304) // TLS 1.3 +} + +// appendPSKKeyExchangeModesExtension appends a psk_key_exchange_modes extension (0x002d). +func appendPSKKeyExchangeModesExtension(b []byte) []byte { + b = appendUint16(b, 0x002d) // extension type + b = appendUint16(b, 2) // extension data length + b = append(b, 1) // modes list length + return append(b, 1) // psk_dhe_ke +} + +// appendALPNExtension appends an application_layer_protocol_negotiation extension (0x0010). +func appendALPNExtension(b []byte, protocols []string) []byte { + // ALPN protocol list: each entry is length(1) + name. + var list []byte + for _, p := range protocols { + list = append(list, byte(len(p))) + list = append(list, []byte(p)...) + } + b = appendUint16(b, 0x0010) // extension type + b = appendUint16(b, uint16(2+len(list))) // extension data length + b = appendUint16(b, uint16(len(list))) // protocol list length + return append(b, list...) +} + +// appendQUICTransportParamsExtension appends a quic_transport_parameters +// extension (0x0039) as required by RFC 9001 §8.2. Includes +// initial_source_connection_id (MUST per RFC 9000 §18.2) and flow control +// parameters that real QUIC clients send. +func appendQUICTransportParamsExtension(b []byte, scid []byte) []byte { + // Format: param_id(varint) + param_len(varint) + value + var params []byte + + // initial_source_connection_id (0x0f) — MUST (RFC 9000 §18.2). + params = append(params, 0x0f) // param ID + params = appendQUICVarint(params, uint64(len(scid))) + params = append(params, scid...) + + // initial_max_data (0x04) = 1 MiB + params = append(params, 0x04) // param ID + params = append(params, 0x04) // length: 4 bytes + params = append(params, 0x80, 0x10, 0x00, 0x00) // 1048576 + + // initial_max_stream_data_bidi_local (0x05) = 256 KiB + params = append(params, 0x05, 0x04, 0x80, 0x04, 0x00, 0x00) + + // initial_max_stream_data_bidi_remote (0x06) = 256 KiB + params = append(params, 0x06, 0x04, 0x80, 0x04, 0x00, 0x00) + + // initial_max_stream_data_uni (0x07) = 256 KiB + params = append(params, 0x07, 0x04, 0x80, 0x04, 0x00, 0x00) + + // initial_max_streams_bidi (0x08) = 100 + params = append(params, 0x08, 0x02, 0x40, 0x64) + + // initial_max_streams_uni (0x09) = 100 + params = append(params, 0x09, 0x02, 0x40, 0x64) + + b = appendUint16(b, 0x0039) // extension type + return append(appendUint16(b, uint16(len(params))), params...) +} From 9c6695a7987fe018fd9a3bd19a26a158357083ec Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 00:34:39 -0500 Subject: [PATCH 02/30] docs: update changelog refs for cipher audit commit Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index d223564..bd15f34 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,10 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added -- Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([`pending`]) -- Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([`pending`]) -- Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([`pending`]) -- Add QUIC/UDP cipher probing to `--ciphers` — automatically probes UDP 443 alongside TCP, shows "QUIC: not supported" when server rejects ([`pending`]) +- Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([`7299fc5`]) +- Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([`7299fc5`]) +- Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([`7299fc5`]) +- Add QUIC/UDP cipher probing to `--ciphers` — automatically probes UDP 443 alongside TCP, shows "QUIC: not supported" when server rejects ([`7299fc5`]) - Auto-generate CLI flag tables in README from Cobra command definitions via `go generate` ([#80]) - Add `gendocs` pre-commit hook and CI check to verify flag tables stay in sync ([#80]) - Add global `--json` persistent flag — all commands now support JSON output; overrides `--format` when both are set ([#80]) @@ -840,6 +840,7 @@ Initial release. [#75]: https://github.com/sensiblebit/certkit/pull/75 [#76]: https://github.com/sensiblebit/certkit/pull/76 [#78]: https://github.com/sensiblebit/certkit/pull/78 +[`7299fc5`]: https://github.com/sensiblebit/certkit/commit/7299fc5 [#80]: https://github.com/sensiblebit/certkit/pull/80 [#73]: https://github.com/sensiblebit/certkit/pull/73 [#64]: https://github.com/sensiblebit/certkit/pull/64 From a8b88efe2955481e6142d8da4ae44e5e937ee101 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 00:36:46 -0500 Subject: [PATCH 03/30] ci: add go mod update and npm update pre-commit hooks Auto-update Go and npm dependencies on every commit to stay ahead of security vulnerabilities, eliminating the need for dependabot PRs. Co-Authored-By: Claude Opus 4.6 --- .pre-commit-config.yaml | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml index f75cd9f..1e4a5d6 100644 --- a/.pre-commit-config.yaml +++ b/.pre-commit-config.yaml @@ -20,6 +20,23 @@ repos: - id: go-build - id: go-test + # ── Dependency Updates ── + - repo: local + hooks: + - id: go-mod-update + name: go mod update + entry: bash -c 'go get -u ./... && go mod tidy' + language: system + files: \.go$ + pass_filenames: false + + - id: npm-update + name: npm update + entry: bash -c 'cd web && npm update' + language: system + files: ^web/ + pass_filenames: false + # ── Docs ── - repo: local hooks: From b6f120b40439da009613225ad38b7b4b65bd3be0 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 00:39:33 -0500 Subject: [PATCH 04/30] build(deps): bump rollup to 4.59.0 and wrangler to 4.20260305.0 Supersedes dependabot PR #81. Co-Authored-By: Claude Opus 4.6 --- web/package-lock.json | 212 +++++++++++++++++++++--------------------- 1 file changed, 106 insertions(+), 106 deletions(-) diff --git a/web/package-lock.json b/web/package-lock.json index 0f76d4b..30dfd1f 100644 --- a/web/package-lock.json +++ b/web/package-lock.json @@ -25,9 +25,9 @@ } }, "node_modules/@cloudflare/workers-types": { - "version": "4.20260304.0", - "resolved": "https://registry.npmjs.org/@cloudflare/workers-types/-/workers-types-4.20260304.0.tgz", - "integrity": "sha512-oQ0QJpWnCWK9tx5q/ZHQeSsf5EcQWa4KqdDMY/R5Ln0ojFzv6UYO0RWsfDPsoXUAwK671VwaXqAW0Mx0uWz7yw==", + "version": "4.20260305.0", + "resolved": "https://registry.npmjs.org/@cloudflare/workers-types/-/workers-types-4.20260305.0.tgz", + "integrity": "sha512-sCgPFnQ03SVpC2OVW8wysONLZW/A8hlp9Mq2ckG/h1oId4kr9NawA6vUiOmOjCWRn2hIohejBYVQ+Vu20rCdKA==", "dev": true, "license": "MIT OR Apache-2.0" }, @@ -596,9 +596,9 @@ "license": "MIT" }, "node_modules/@rollup/rollup-android-arm-eabi": { - 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"@rollup/rollup-android-arm-eabi": "4.57.1", - "@rollup/rollup-android-arm64": "4.57.1", - "@rollup/rollup-darwin-arm64": "4.57.1", - "@rollup/rollup-darwin-x64": "4.57.1", - "@rollup/rollup-freebsd-arm64": "4.57.1", - "@rollup/rollup-freebsd-x64": "4.57.1", - "@rollup/rollup-linux-arm-gnueabihf": "4.57.1", - "@rollup/rollup-linux-arm-musleabihf": "4.57.1", - "@rollup/rollup-linux-arm64-gnu": "4.57.1", - "@rollup/rollup-linux-arm64-musl": "4.57.1", - "@rollup/rollup-linux-loong64-gnu": "4.57.1", - "@rollup/rollup-linux-loong64-musl": "4.57.1", - "@rollup/rollup-linux-ppc64-gnu": "4.57.1", - "@rollup/rollup-linux-ppc64-musl": "4.57.1", - "@rollup/rollup-linux-riscv64-gnu": "4.57.1", - "@rollup/rollup-linux-riscv64-musl": "4.57.1", - "@rollup/rollup-linux-s390x-gnu": "4.57.1", - "@rollup/rollup-linux-x64-gnu": "4.57.1", - "@rollup/rollup-linux-x64-musl": "4.57.1", - "@rollup/rollup-openbsd-x64": "4.57.1", - "@rollup/rollup-openharmony-arm64": "4.57.1", - "@rollup/rollup-win32-arm64-msvc": "4.57.1", - "@rollup/rollup-win32-ia32-msvc": "4.57.1", - "@rollup/rollup-win32-x64-gnu": "4.57.1", - "@rollup/rollup-win32-x64-msvc": "4.57.1", + "@rollup/rollup-android-arm-eabi": "4.59.0", + "@rollup/rollup-android-arm64": "4.59.0", + "@rollup/rollup-darwin-arm64": "4.59.0", + "@rollup/rollup-darwin-x64": "4.59.0", + "@rollup/rollup-freebsd-arm64": "4.59.0", + "@rollup/rollup-freebsd-x64": "4.59.0", + "@rollup/rollup-linux-arm-gnueabihf": "4.59.0", + "@rollup/rollup-linux-arm-musleabihf": "4.59.0", + "@rollup/rollup-linux-arm64-gnu": "4.59.0", + "@rollup/rollup-linux-arm64-musl": "4.59.0", + "@rollup/rollup-linux-loong64-gnu": "4.59.0", + "@rollup/rollup-linux-loong64-musl": "4.59.0", + "@rollup/rollup-linux-ppc64-gnu": "4.59.0", + "@rollup/rollup-linux-ppc64-musl": "4.59.0", + "@rollup/rollup-linux-riscv64-gnu": "4.59.0", + "@rollup/rollup-linux-riscv64-musl": "4.59.0", + "@rollup/rollup-linux-s390x-gnu": "4.59.0", + "@rollup/rollup-linux-x64-gnu": "4.59.0", + "@rollup/rollup-linux-x64-musl": "4.59.0", + "@rollup/rollup-openbsd-x64": "4.59.0", + "@rollup/rollup-openharmony-arm64": "4.59.0", + "@rollup/rollup-win32-arm64-msvc": "4.59.0", + "@rollup/rollup-win32-ia32-msvc": "4.59.0", + "@rollup/rollup-win32-x64-gnu": "4.59.0", + "@rollup/rollup-win32-x64-msvc": "4.59.0", "fsevents": "~2.3.2" } }, From 1adb9b5f5350bc7cf0910fe980302bdc246550f4 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 00:59:44 -0500 Subject: [PATCH 05/30] fix: harden QUIC/TLS parsers, address PR review feedback MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Add bounds checks for DCID/SCID lengths in QUIC response parser - Add varint decode guards to prevent infinite loops on malformed ACK frames - Increase UDP read buffer from 4096 to 65535 bytes - Add session ID length bounds check in TLS ServerHello parser - Refactor probe functions to use cipherProbeInput struct (CS-5) - Fix EXAMPLES.md cipher rating terminology ("strong" → "good") - Consolidate tests per T-9/T-11/T-12, add parser edge case coverage Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 8 + EXAMPLES.md | 2 +- connect.go | 33 ++-- connect_test.go | 419 ++++++++++++++++++------------------------------ quicprobe.go | 76 +++++++-- tls13probe.go | 34 ++-- 6 files changed, 270 insertions(+), 302 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index bd15f34..5ecbf1b 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -57,6 +57,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed +- Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([`pending`]) +- Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([`pending`]) +- Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([`pending`]) - **Breaking:** Rename `csr --cert` flag to `--from-cert` for clarity — avoids confusion with certificate file arguments in other commands ([#80]) - **Breaking:** `connect` JSON `sha256_fingerprint` format changed from lowercase hex to colon-separated uppercase hex for CLI-4 consistency with `inspect` and `sha1_fingerprint` ([#80]) - **Breaking:** Rename `CRLCheckResult.DistributionPoint` to `CRLCheckResult.URL` (JSON: `url`) and `OCSPResult.ResponderURL` to `OCSPResult.URL` (JSON: `url`) — consistent field name for the checked endpoint across both revocation types (CLI-4) ([#78]) @@ -146,6 +149,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests +- Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`pending`]) +- Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`pending`]) +- Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`pending`]) +- Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([`pending`]) +- Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([`pending`]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) diff --git a/EXAMPLES.md b/EXAMPLES.md index dda4103..efea11b 100644 --- a/EXAMPLES.md +++ b/EXAMPLES.md @@ -184,7 +184,7 @@ To enumerate all cipher suites the server supports with security ratings: certkit connect example.com --ciphers ``` -Each cipher suite is rated `strong` (ECDHE + AEAD, all TLS 1.3 suites) or `weak` (CBC, static RSA, RC4, 3DES). Weak ciphers are listed with a warning recommending they be disabled. +Each cipher suite is rated `good` (ECDHE + AEAD, all TLS 1.3 suites) or `weak` (CBC, static RSA, RC4, 3DES). Weak ciphers are listed with a warning recommending they be disabled. For machine-readable output: diff --git a/connect.go b/connect.go index 2922a60..83171c2 100644 --- a/connect.go +++ b/connect.go @@ -784,7 +784,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) defer probeCancel() - if probeTLS13Cipher(probeCtx, addr, serverName, cipherID) { + if probeTLS13Cipher(probeCtx, cipherProbeInput{addr: addr, serverName: serverName, cipherID: cipherID}) { r := CipherProbeResult{ Name: cipherSuiteName(cipherID), ID: cipherID, @@ -831,7 +831,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) defer probeCancel() - if probeCipher(probeCtx, addr, serverName, t.id, t.version) { + if probeCipher(probeCtx, cipherProbeInput{addr: addr, serverName: serverName, cipherID: t.id, version: t.version}) { name := cipherSuiteName(t.id) r := CipherProbeResult{ Name: name, @@ -868,13 +868,14 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) defer probeCancel() - accepted := probeKeyExchangeGroup(probeCtx, addr, serverName, groupID) + probeInput := cipherProbeInput{addr: addr, serverName: serverName, groupID: groupID} + accepted := probeKeyExchangeGroup(probeCtx, probeInput) // For classical (non-PQ) groups, also probe TLS 1.0–1.2 if TLS 1.3 didn't work. if !accepted && !isPQKeyExchange(groupID) { probeCtx2, probeCancel2 := context.WithTimeout(ctx, probeTimeout) defer probeCancel2() - accepted = probeKeyExchangeGroupLegacy(probeCtx2, addr, serverName, groupID) + accepted = probeKeyExchangeGroupLegacy(probeCtx2, probeInput) } if accepted { @@ -911,7 +912,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) defer probeCancel() - if probeQUICCipher(probeCtx, quicAddr, serverName, cipherID) { + if probeQUICCipher(probeCtx, cipherProbeInput{addr: quicAddr, serverName: serverName, cipherID: cipherID}) { r := CipherProbeResult{ Name: cipherSuiteName(cipherID), ID: cipherID, @@ -1002,18 +1003,18 @@ func emptyClientCert(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) { // probeCipher attempts a TLS handshake offering only the specified cipher suite at the given version. // Returns true if the server accepted the cipher, even if the handshake // ultimately fails (e.g. mTLS rejection after cipher negotiation). -func probeCipher(ctx context.Context, addr, serverName string, cipherID uint16, version uint16) bool { +func probeCipher(ctx context.Context, input cipherProbeInput) bool { dialer := &net.Dialer{} - conn, err := dialer.DialContext(ctx, "tcp", addr) + conn, err := dialer.DialContext(ctx, "tcp", input.addr) if err != nil { return false } tlsConn := tls.Client(conn, &tls.Config{ - ServerName: serverName, + ServerName: input.serverName, InsecureSkipVerify: true, //nolint:gosec // Cipher probing doesn't need cert verification. - MinVersion: version, - MaxVersion: version, - CipherSuites: []uint16{cipherID}, + MinVersion: input.version, + MaxVersion: input.version, + CipherSuites: []uint16{input.cipherID}, GetClientCertificate: emptyClientCert, }) defer func() { _ = tlsConn.Close() }() @@ -1026,7 +1027,7 @@ func probeCipher(ctx context.Context, addr, serverName string, cipherID uint16, } // Handshake failed, but check if the server negotiated our cipher before aborting. state := tlsConn.ConnectionState() - return state.Version == version && state.CipherSuite == cipherID + return state.Version == input.version && state.CipherSuite == input.cipherID } // ecdheOnlyCipherSuites contains only ECDHE-based TLS 1.0–1.2 cipher suites. @@ -1047,19 +1048,19 @@ var ecdheOnlyCipherSuites = func() []uint16 { // CurvePreferences entry and returns true if the server accepts the group. Only // ECDHE cipher suites are offered so the handshake fails if the server doesn't // support the offered curve (RSA key exchange would bypass curve negotiation). -func probeKeyExchangeGroupLegacy(ctx context.Context, addr, serverName string, groupID tls.CurveID) bool { +func probeKeyExchangeGroupLegacy(ctx context.Context, input cipherProbeInput) bool { dialer := &net.Dialer{} - conn, err := dialer.DialContext(ctx, "tcp", addr) + conn, err := dialer.DialContext(ctx, "tcp", input.addr) if err != nil { return false } tlsConn := tls.Client(conn, &tls.Config{ - ServerName: serverName, + ServerName: input.serverName, InsecureSkipVerify: true, //nolint:gosec // Probing doesn't need cert verification. MinVersion: tls.VersionTLS10, MaxVersion: tls.VersionTLS12, CipherSuites: ecdheOnlyCipherSuites, - CurvePreferences: []tls.CurveID{groupID}, + CurvePreferences: []tls.CurveID{input.groupID}, GetClientCertificate: emptyClientCert, }) defer func() { _ = tlsConn.Close() }() diff --git a/connect_test.go b/connect_test.go index 9426a53..8af07d8 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1,6 +1,7 @@ package certkit import ( + "bytes" "context" "crypto/ecdsa" "crypto/elliptic" @@ -297,6 +298,8 @@ func TestFormatConnectResult(t *testing.T) { name string diagnostics []ChainDiagnostic aiaFetched bool + verifyError string + clientAuth *ClientAuthInfo ocsp *OCSPResult crl *CRLCheckResult wantStrings []string @@ -376,6 +379,21 @@ func TestFormatConnectResult(t *testing.T) { "OCSP: skipped (certificate has no OCSP responder URL)", }, }, + { + name: "verify failed", + verifyError: "x509: certificate signed by unknown authority", + wantStrings: []string{ + "Verify: FAILED (x509: certificate signed by unknown authority)", + }, + notWantStrings: []string{"Verify: OK"}, + }, + { + name: "client auth requested (any CA)", + clientAuth: &ClientAuthInfo{Requested: true}, + wantStrings: []string{ + "Client Auth: requested (any CA)", + }, + }, { name: "CRL good", crl: &CRLCheckResult{Status: "good", URL: "http://crl.example.com/ca.crl"}, @@ -404,6 +422,8 @@ func TestFormatConnectResult(t *testing.T) { PeerChain: []*x509.Certificate{cert}, Diagnostics: tt.diagnostics, AIAFetched: tt.aiaFetched, + VerifyError: tt.verifyError, + ClientAuth: tt.clientAuth, OCSP: tt.ocsp, CRL: tt.crl, } @@ -1421,6 +1441,49 @@ func TestFormatCipherScanResult(t *testing.T) { "[good]", }, }, + { + name: "QUIC and key exchanges", + result: &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + QUICProbed: true, + QUICCiphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_AES_256_GCM_SHA384", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + KeyExchanges: []KeyExchangeProbeResult{ + {Name: "X25519MLKEM768", ID: 4588, PostQuantum: true}, + {Name: "X25519", ID: 29}, + {Name: "P-256", ID: 23}, + }, + OverallRating: CipherRatingGood, + }, + wantStrings: []string{ + "Cipher suites (1 supported)", + "QUIC cipher suites (2 supported)", + "Key exchange groups (3 supported, forward secrecy)", + "X25519MLKEM768 (post-quantum)", + "X25519\n", + "P-256\n", + }, + }, + { + name: "QUIC probed but not supported", + result: &CipherScanResult{ + SupportedVersions: []string{"TLS 1.3"}, + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + }, + QUICProbed: true, + QUICCiphers: nil, + OverallRating: CipherRatingGood, + }, + wantStrings: []string{ + "QUIC: not supported", + }, + }, } for _, tt := range tests { @@ -1658,73 +1721,80 @@ func TestConnectTLS_CRL_DuplicateLeafInChain(t *testing.T) { func TestBuildClientHello(t *testing.T) { t.Parallel() - msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: "example.com", - cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 - groupID: tls.X25519, - }) - if err != nil { - t.Fatalf("buildClientHelloMsg failed: %v", err) - } + t.Run("TCP mode", func(t *testing.T) { + t.Parallel() + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: "example.com", + cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 + groupID: tls.X25519, + }) + if err != nil { + t.Fatalf("buildClientHelloMsg failed: %v", err) + } - // Handshake type must be ClientHello (0x01). - if msg[0] != 0x01 { - t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) - } + // Handshake type must be ClientHello (0x01). + if msg[0] != 0x01 { + t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) + } - // Handshake length (3 bytes, big-endian) must match actual body length. - handshakeLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) - if handshakeLen != len(msg)-4 { - t.Errorf("handshake length = %d, want %d", handshakeLen, len(msg)-4) - } + // Handshake length (3 bytes, big-endian) must match actual body length. + handshakeLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) + if handshakeLen != len(msg)-4 { + t.Errorf("handshake length = %d, want %d", handshakeLen, len(msg)-4) + } - // Legacy version at body[0:2] must be TLS 1.2 (0x0303). - if msg[4] != 0x03 || msg[5] != 0x03 { - t.Errorf("legacy version = 0x%02x%02x, want 0x0303", msg[4], msg[5]) - } + // Legacy version at body[0:2] must be TLS 1.2 (0x0303). + if msg[4] != 0x03 || msg[5] != 0x03 { + t.Errorf("legacy version = 0x%02x%02x, want 0x0303", msg[4], msg[5]) + } - // Client random is 32 bytes starting at body[2]. - // Session ID length at body[34], session ID follows. - sessionIDLen := int(msg[4+34]) - if sessionIDLen != 32 { - t.Errorf("session ID length = %d, want 32", sessionIDLen) - } + // Session ID length at body[34] — TCP mode uses 32-byte session ID. + sessionIDLen := int(msg[4+34]) + if sessionIDLen != 32 { + t.Errorf("session ID length = %d, want 32", sessionIDLen) + } - // Cipher suite list starts after session ID. - csOffset := 4 + 35 + sessionIDLen - csListLen := int(msg[csOffset])<<8 | int(msg[csOffset+1]) - if csListLen != 2 { - t.Errorf("cipher suite list length = %d, want 2 (single cipher)", csListLen) - } - csID := uint16(msg[csOffset+2])<<8 | uint16(msg[csOffset+3]) - if csID != 0x1301 { - t.Errorf("cipher suite = 0x%04x, want 0x1301", csID) - } -} + // Cipher suite list starts after session ID. + csOffset := 4 + 35 + sessionIDLen + csListLen := int(msg[csOffset])<<8 | int(msg[csOffset+1]) + if csListLen != 2 { + t.Errorf("cipher suite list length = %d, want 2 (single cipher)", csListLen) + } + csID := uint16(msg[csOffset+2])<<8 | uint16(msg[csOffset+3]) + if csID != 0x1301 { + t.Errorf("cipher suite = 0x%04x, want 0x1301", csID) + } + }) -func TestBuildClientHello_WithALPN(t *testing.T) { - t.Parallel() + t.Run("QUIC mode with ALPN", func(t *testing.T) { + t.Parallel() + msg, err := buildClientHelloMsg(clientHelloInput{ + serverName: "example.com", + cipherSuite: 0x1301, + groupID: tls.X25519, + alpn: []string{"h3"}, + quic: true, + }) + if err != nil { + t.Fatalf("buildClientHelloMsg with ALPN failed: %v", err) + } - msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: "example.com", - cipherSuite: 0x1301, - groupID: tls.X25519, - alpn: []string{"h3"}, - quic: true, - }) - if err != nil { - t.Fatalf("buildClientHelloMsg with ALPN failed: %v", err) - } + // Handshake type must be ClientHello (0x01). + if msg[0] != 0x01 { + t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) + } - // Message must contain the ALPN extension (type 0x0010) with "h3". - if !containsBytes(msg, []byte("h3")) { - t.Error("ClientHello missing ALPN 'h3'") - } + // QUIC mode: session ID must be empty (RFC 9001 §8.4). + sessionIDLen := int(msg[4+34]) + if sessionIDLen != 0 { + t.Errorf("QUIC session ID length = %d, want 0", sessionIDLen) + } - // Must also be a valid handshake message. - if msg[0] != 0x01 { - t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) - } + // Message must contain the ALPN extension with "h3". + if !bytes.Contains(msg, []byte("h3")) { + t.Error("ClientHello missing ALPN 'h3'") + } + }) } func TestParseServerHello(t *testing.T) { @@ -1764,6 +1834,37 @@ func TestParseServerHello(t *testing.T) { data: buildTestServerHelloHRR(0x1301), wantErr: "HelloRetryRequest", }, + { + name: "oversized session ID length causes truncation", + // Handshake header(4) + version(2) + random(32) + sessionIDLen(1) = 39 bytes body. + // sessionIDLen=200 causes pos to jump past body, caught at cipher suite bounds check. + data: func() []byte { + body := make([]byte, 35) + body[0], body[1] = 0x03, 0x03 // version + body[34] = 200 // sessionIDLen far exceeds body + msg := []byte{0x02} + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg + }(), + wantErr: "truncated at session ID", + }, + { + name: "truncated at compression method", + // Body: version(2) + random(32) + sessionIDLen(1,val=0) + cipher(2) = 37 bytes. + // No compression method byte. + data: func() []byte { + body := make([]byte, 37) + body[0], body[1] = 0x03, 0x03 // version + body[34] = 0 // sessionIDLen = 0 + body[35], body[36] = 0x13, 0x01 + msg := []byte{0x02} + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg + }(), + wantErr: "truncated at compression method", + }, } for _, tt := range tests { @@ -1792,67 +1893,6 @@ func TestParseServerHello(t *testing.T) { } } -func TestGenerateKeyShare(t *testing.T) { - t.Parallel() - - tests := []struct { - name string - groupID tls.CurveID - wantLen int - }{ - {"X25519", tls.X25519, 32}, - {"P-256", tls.CurveP256, 65}, - {"P-384", tls.CurveP384, 97}, - {"P-521", tls.CurveP521, 133}, - {"X25519MLKEM768", tls.X25519MLKEM768, 1184 + 32}, // ML-KEM-768 encap key + X25519 - {"SecP256r1MLKEM768", tls.SecP256r1MLKEM768, 65 + 1184}, // P-256 + ML-KEM-768 - {"SecP384r1MLKEM1024", tls.SecP384r1MLKEM1024, 97 + 1568}, // P-384 + ML-KEM-1024 - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - t.Parallel() - data, err := generateKeyShare(tt.groupID) - if err != nil { - t.Fatalf("generateKeyShare(%s) failed: %v", tt.name, err) - } - if len(data) != tt.wantLen { - t.Errorf("key share length = %d, want %d", len(data), tt.wantLen) - } - }) - } -} - -func TestGenerateKeyShare_UnsupportedGroup(t *testing.T) { - t.Parallel() - _, err := generateKeyShare(tls.CurveID(0xFFFF)) - if err == nil { - t.Fatal("expected error for unsupported group") - } -} - -func TestDeriveQUICInitialKeys(t *testing.T) { - t.Parallel() - - // RFC 9001 Appendix A test vectors. - dcid := hexDecode(t, "8394c8f03e515708") - - client, server, err := deriveQUICInitialKeys(dcid) - if err != nil { - t.Fatalf("deriveQUICInitialKeys failed: %v", err) - } - - // Client keys. - assertHex(t, "client key", client.key, "1f369613dd76d5467730efcbe3b1a22d") - assertHex(t, "client iv", client.iv, "fa044b2f42a3fd3b46fb255c") - assertHex(t, "client hp", client.hp, "9f50449e04a0e810283a1e9933adedd2") - - // Server keys. - assertHex(t, "server key", server.key, "cf3a5331653c364c88f0f379b6067e37") - assertHex(t, "server iv", server.iv, "0ac1493ca1905853b0bba03e") - assertHex(t, "server hp", server.hp, "c206b8d9b9f0f37644430b490eeaa314") -} - func TestBuildQUICInitialPacket(t *testing.T) { t.Parallel() @@ -1921,7 +1961,7 @@ func TestProbeTLS13Cipher_Concurrent(t *testing.T) { go func(idx int) { defer wg.Done() cipherID := tls13CipherSuites[idx%len(tls13CipherSuites)] - probeTLS13Cipher(ctx, addr, "127.0.0.1", cipherID) + probeTLS13Cipher(ctx, cipherProbeInput{addr: addr, serverName: "127.0.0.1", cipherID: cipherID}) }(i) } wg.Wait() @@ -1977,126 +2017,6 @@ func TestScanCipherSuites_KeyExchanges(t *testing.T) { } } -func TestFormatCipherScanResult_QUICAndKeyExchanges(t *testing.T) { - t.Parallel() - - result := &CipherScanResult{ - SupportedVersions: []string{"TLS 1.3"}, - Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, - }, - QUICProbed: true, - QUICCiphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, - {Name: "TLS_AES_256_GCM_SHA384", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, - }, - KeyExchanges: []KeyExchangeProbeResult{ - {Name: "X25519MLKEM768", ID: 4588, PostQuantum: true}, - {Name: "X25519", ID: 29}, - {Name: "P-256", ID: 23}, - }, - OverallRating: CipherRatingGood, - } - - output := FormatCipherScanResult(result) - - for _, want := range []string{ - "Cipher suites (1 supported)", - "QUIC cipher suites (2 supported)", - "Key exchange groups (3 supported, forward secrecy)", - "X25519MLKEM768 (post-quantum)", - "X25519\n", - "P-256\n", - } { - if !strings.Contains(output, want) { - t.Errorf("output missing %q\ngot:\n%s", want, output) - } - } -} - -func TestFormatCipherScanResult_QUICNotSupported(t *testing.T) { - t.Parallel() - - result := &CipherScanResult{ - SupportedVersions: []string{"TLS 1.3"}, - Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, - }, - QUICProbed: true, - QUICCiphers: nil, - OverallRating: CipherRatingGood, - } - - output := FormatCipherScanResult(result) - - if !strings.Contains(output, "QUIC: not supported") { - t.Errorf("expected QUIC not supported line\ngot:\n%s", output) - } -} - -func TestIsPQKeyExchange(t *testing.T) { - t.Parallel() - - tests := []struct { - id tls.CurveID - want bool - }{ - {tls.X25519MLKEM768, true}, - {tls.SecP256r1MLKEM768, true}, - {tls.SecP384r1MLKEM1024, true}, - {tls.X25519, false}, - {tls.CurveP256, false}, - {tls.CurveP384, false}, - {tls.CurveP521, false}, - } - - for _, tt := range tests { - if got := isPQKeyExchange(tt.id); got != tt.want { - t.Errorf("isPQKeyExchange(%s) = %v, want %v", tt.id, got, tt.want) - } - } -} - -func TestQUICVarint(t *testing.T) { - t.Parallel() - - tests := []struct { - name string - val uint64 - want []byte - }{ - {"zero", 0, []byte{0x00}}, - {"one byte max", 63, []byte{0x3f}}, - {"two byte min", 64, []byte{0x40, 0x40}}, - {"two byte max", 16383, []byte{0x7f, 0xff}}, - {"four byte min", 16384, []byte{0x80, 0x00, 0x40, 0x00}}, - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - t.Parallel() - got := appendQUICVarint(nil, tt.val) - if len(got) != len(tt.want) { - t.Fatalf("length = %d, want %d", len(got), len(tt.want)) - } - for i := range got { - if got[i] != tt.want[i] { - t.Errorf("byte[%d] = 0x%02x, want 0x%02x", i, got[i], tt.want[i]) - } - } - - // Round-trip through decode. - decoded, n := decodeQUICVarint(got) - if decoded != tt.val { - t.Errorf("decode = %d, want %d", decoded, tt.val) - } - if n != len(got) { - t.Errorf("decode consumed %d bytes, want %d", n, len(got)) - } - }) - } -} - // ---------- test helpers ---------- // buildTestServerHello constructs a minimal TLS 1.3 ServerHello handshake message @@ -2173,16 +2093,6 @@ func buildTestServerHello12(cipherSuite uint16) []byte { return msg } -// containsBytes reports whether b contains the subslice sub. -func containsBytes(b, sub []byte) bool { - for i := range len(b) - len(sub) + 1 { - if string(b[i:i+len(sub)]) == string(sub) { - return true - } - } - return false -} - // hexDecode decodes a hex string, failing the test on error. func hexDecode(t *testing.T, s string) []byte { t.Helper() @@ -2192,12 +2102,3 @@ func hexDecode(t *testing.T, s string) []byte { } return b } - -// assertHex compares a byte slice to an expected hex string. -func assertHex(t *testing.T, name string, got []byte, wantHex string) { - t.Helper() - gotHex := hex.EncodeToString(got) - if gotHex != wantHex { - t.Errorf("%s = %s, want %s", name, gotHex, wantHex) - } -} diff --git a/quicprobe.go b/quicprobe.go index c1a205e..d4f0d1b 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -235,21 +235,36 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return nil, fmt.Errorf("packet truncated at DCID length") } dcidLen := int(packet[pos]) - pos += 1 + dcidLen + pos++ + if pos+dcidLen > len(packet) { + return nil, fmt.Errorf("packet truncated at DCID: need %d bytes", dcidLen) + } + pos += dcidLen // SCID. if pos+1 > len(packet) { return nil, fmt.Errorf("packet truncated at SCID length") } scidLen := int(packet[pos]) - pos += 1 + scidLen + pos++ + if pos+scidLen > len(packet) { + return nil, fmt.Errorf("packet truncated at SCID: need %d bytes", scidLen) + } + pos += scidLen // Token length (varint). if pos >= len(packet) { return nil, fmt.Errorf("packet truncated at token length") } tokenLen, tokenVarLen := decodeQUICVarint(packet[pos:]) - pos += tokenVarLen + int(tokenLen) + if tokenVarLen == 0 { + return nil, fmt.Errorf("malformed token length varint") + } + pos += tokenVarLen + if pos+int(tokenLen) > len(packet) { + return nil, fmt.Errorf("packet truncated at token data") + } + pos += int(tokenLen) // Payload length (varint) — covers packet number + encrypted data + AEAD tag. // Must be kept to avoid decrypting coalesced packets (Initial + Handshake). @@ -257,6 +272,9 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return nil, fmt.Errorf("packet truncated at payload length") } payloadLen, payloadVarLen := decodeQUICVarint(packet[pos:]) + if payloadVarLen == 0 { + return nil, fmt.Errorf("malformed payload length varint") + } pos += payloadVarLen pnOffset := pos @@ -342,27 +360,46 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve // ACK frame (RFC 9000 §19.3): parse and skip. fpos++ _, varLen := decodeQUICVarint(plaintext[fpos:]) // Largest Acknowledged + if varLen == 0 { + break + } fpos += varLen _, varLen = decodeQUICVarint(plaintext[fpos:]) // ACK Delay + if varLen == 0 { + break + } fpos += varLen rangeCount, varLen := decodeQUICVarint(plaintext[fpos:]) // ACK Range Count + if varLen == 0 { + break + } fpos += varLen _, varLen = decodeQUICVarint(plaintext[fpos:]) // First ACK Range + if varLen == 0 { + break + } fpos += varLen for range rangeCount { _, varLen = decodeQUICVarint(plaintext[fpos:]) // Gap + if varLen == 0 { + break + } fpos += varLen _, varLen = decodeQUICVarint(plaintext[fpos:]) // ACK Range Length + if varLen == 0 { + break + } fpos += varLen } if frameType == 0x03 { // ACK_ECN has 3 additional varints. - _, varLen = decodeQUICVarint(plaintext[fpos:]) - fpos += varLen - _, varLen = decodeQUICVarint(plaintext[fpos:]) - fpos += varLen - _, varLen = decodeQUICVarint(plaintext[fpos:]) - fpos += varLen + for range 3 { + _, varLen = decodeQUICVarint(plaintext[fpos:]) + if varLen == 0 { + break + } + fpos += varLen + } } continue } @@ -374,9 +411,15 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve // CRYPTO frame. fpos++ // skip frame type _, varLen := decodeQUICVarint(plaintext[fpos:]) + if varLen == 0 { + return nil, fmt.Errorf("malformed CRYPTO frame offset") + } fpos += varLen // skip offset dataLen, varLen := decodeQUICVarint(plaintext[fpos:]) + if varLen == 0 { + return nil, fmt.Errorf("malformed CRYPTO frame length") + } fpos += varLen if fpos+int(dataLen) > len(plaintext) { @@ -393,7 +436,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve // probeQUICCipher sends a QUIC Initial packet to UDP 443 with a single // cipher suite and returns true if the server accepts it. -func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint16) bool { +func probeQUICCipher(ctx context.Context, input cipherProbeInput) bool { // Generate random connection IDs. dcid := make([]byte, 8) scid := make([]byte, 8) @@ -408,8 +451,8 @@ func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint // QUIC requires ALPN ("h3"), quic_transport_parameters, and an empty session ID // (RFC 9001 §8.4). msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: serverName, - cipherSuite: cipherID, + serverName: input.serverName, + cipherSuite: input.cipherID, groupID: tls.X25519, alpn: []string{"h3"}, quic: true, @@ -431,7 +474,7 @@ func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint // Send via UDP. dialer := &net.Dialer{} - conn, err := dialer.DialContext(ctx, "udp", addr) + conn, err := dialer.DialContext(ctx, "udp", input.addr) if err != nil { return false } @@ -445,8 +488,9 @@ func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint return false } - // Read response. QUIC Initial responses can be up to ~1400 bytes. - buf := make([]byte, 4096) + // Read response. Server Initial packets can include coalesced Handshake + // packets, so allocate a full UDP datagram buffer. + buf := make([]byte, 65535) n, err := conn.Read(buf) if err != nil { return false @@ -464,7 +508,7 @@ func probeQUICCipher(ctx context.Context, addr, serverName string, cipherID uint return false } - return result.version == tls.VersionTLS13 && result.cipherSuite == cipherID + return result.version == tls.VersionTLS13 && result.cipherSuite == input.cipherID } // ---------- QUIC varint helpers ---------- diff --git a/tls13probe.go b/tls13probe.go index 0fda940..50ed0a9 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -315,7 +315,11 @@ func parseServerHello(data []byte) (*serverHelloResult, error) { // Session ID. sessionIDLen := int(body[pos]) - pos += 1 + sessionIDLen + pos++ + if pos+sessionIDLen > len(body) { + return nil, fmt.Errorf("ServerHello truncated at session ID") + } + pos += sessionIDLen // Cipher suite (2 bytes). if pos+2 > len(body) { @@ -364,12 +368,22 @@ func parseServerHello(data []byte) (*serverHelloResult, error) { }, nil } +// cipherProbeInput contains parameters for probing a single cipher suite +// or key exchange group on a TLS server. +type cipherProbeInput struct { + addr string + serverName string + cipherID uint16 + groupID tls.CurveID + version uint16 // for legacy TLS 1.0–1.2 probing +} + // probeTLS13Cipher attempts a raw TLS 1.3 ClientHello with a single cipher // suite and returns true if the server accepts it. Each call is fully isolated // with no shared state — safe for concurrent use from multiple goroutines. -func probeTLS13Cipher(ctx context.Context, addr, serverName string, cipherID uint16) bool { +func probeTLS13Cipher(ctx context.Context, input cipherProbeInput) bool { dialer := &net.Dialer{} - conn, err := dialer.DialContext(ctx, "tcp", addr) + conn, err := dialer.DialContext(ctx, "tcp", input.addr) if err != nil { return false } @@ -380,8 +394,8 @@ func probeTLS13Cipher(ctx context.Context, addr, serverName string, cipherID uin } msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: serverName, - cipherSuite: cipherID, + serverName: input.serverName, + cipherSuite: input.cipherID, groupID: tls.X25519, }) if err != nil { @@ -397,15 +411,15 @@ func probeTLS13Cipher(ctx context.Context, addr, serverName string, cipherID uin return false } - return result.version == tls.VersionTLS13 && result.cipherSuite == cipherID + return result.version == tls.VersionTLS13 && result.cipherSuite == input.cipherID } // probeKeyExchangeGroup attempts a raw TLS 1.3 ClientHello offering a single // named group and returns true if the server selects it. Uses // TLS_AES_128_GCM_SHA256 as the cipher since all TLS 1.3 servers must support it. -func probeKeyExchangeGroup(ctx context.Context, addr, serverName string, groupID tls.CurveID) bool { +func probeKeyExchangeGroup(ctx context.Context, input cipherProbeInput) bool { dialer := &net.Dialer{} - conn, err := dialer.DialContext(ctx, "tcp", addr) + conn, err := dialer.DialContext(ctx, "tcp", input.addr) if err != nil { return false } @@ -416,9 +430,9 @@ func probeKeyExchangeGroup(ctx context.Context, addr, serverName string, groupID } msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: serverName, + serverName: input.serverName, cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 - groupID: groupID, + groupID: input.groupID, }) if err != nil { return false From 5c72f872cf49d56690d4ebb21917c5b3db3e8e3e Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 01:00:20 -0500 Subject: [PATCH 06/30] docs: update changelog refs from pending to 1adb9b5 Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 5ecbf1b..f9884cc 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -57,9 +57,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed -- Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([`pending`]) -- Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([`pending`]) -- Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([`pending`]) +- Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([`1adb9b5`]) +- Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([`1adb9b5`]) +- Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([`1adb9b5`]) - **Breaking:** Rename `csr --cert` flag to `--from-cert` for clarity — avoids confusion with certificate file arguments in other commands ([#80]) - **Breaking:** `connect` JSON `sha256_fingerprint` format changed from lowercase hex to colon-separated uppercase hex for CLI-4 consistency with `inspect` and `sha1_fingerprint` ([#80]) - **Breaking:** Rename `CRLCheckResult.DistributionPoint` to `CRLCheckResult.URL` (JSON: `url`) and `OCSPResult.ResponderURL` to `OCSPResult.URL` (JSON: `url`) — consistent field name for the checked endpoint across both revocation types (CLI-4) ([#78]) @@ -149,11 +149,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests -- Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`pending`]) -- Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`pending`]) -- Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`pending`]) -- Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([`pending`]) -- Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([`pending`]) +- Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`1adb9b5`]) +- Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`1adb9b5`]) +- Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`1adb9b5`]) +- Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([`1adb9b5`]) +- Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([`1adb9b5`]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) @@ -849,6 +849,7 @@ Initial release. [#76]: https://github.com/sensiblebit/certkit/pull/76 [#78]: https://github.com/sensiblebit/certkit/pull/78 [`7299fc5`]: https://github.com/sensiblebit/certkit/commit/7299fc5 +[`1adb9b5`]: https://github.com/sensiblebit/certkit/commit/1adb9b5 [#80]: https://github.com/sensiblebit/certkit/pull/80 [#73]: https://github.com/sensiblebit/certkit/pull/73 [#64]: https://github.com/sensiblebit/certkit/pull/64 From 18ed2885911a960fff44ffab1a0fd82e073ec802 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 01:17:52 -0500 Subject: [PATCH 07/30] fix: harden QUIC parser, fix CLI error wrapping, consolidate tests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Address adversarial review findings from PR #82: - Guard QUIC varint uint64→int casts with uint64-space bounds checks to prevent truncation on malicious packets - Fix ACK range loop inner break not propagating to outer frame parser - Cap ACK rangeCount to plaintext length to prevent CPU exhaustion - Remove double-wrapped error messages in connect CLI - Initialize CipherScanResult nil slices to empty for JSON encoding - Strengthen TestBuildQUICInitialPacket with header + round-trip decrypt - Consolidate TestRateCipherSuite from 13 to 6 entries (T-12) - Merge TestScanCipherSuites_KeyExchanges into TestScanCipherSuites (T-14) - Fix brittle tls13Count != 3 assertion Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 9 ++ cmd/certkit/connect.go | 4 +- connect.go | 8 ++ connect_test.go | 261 +++++++++++++++++++++++------------------ quicprobe.go | 21 +++- 5 files changed, 187 insertions(+), 116 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index f9884cc..b48f60c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,6 +76,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed +- Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([`pending`]) +- Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([`pending`]) +- Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([`pending`]) +- Fix double-wrapped error messages in `connect` CLI — "connecting to: connecting to:" and "scanning cipher suites: scanning cipher suites:" ([`pending`]) +- Fix `CipherScanResult` JSON encoding `supported_versions` and `ciphers` as `null` instead of `[]` when no ciphers detected ([`pending`]) - Fix backtick-quoted values in flag usage strings being consumed by pflag as type placeholders — all `--format`, `--trust-store`, `--log-level`, `--algorithm`, and `--curve` flags now display correctly in `--help` output ([#80]) - Fix `convert --json` without `-o` missing `format` field in JSON output ([#80]) - Fix data race in `TestCheckLeafCRL` — CRL bytes are now generated before starting the test HTTP server (CC-3) ([#78]) @@ -149,6 +154,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests +- Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([`pending`]) +- Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([`pending`]) +- Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([`pending`]) +- Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([`pending`]) - Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`1adb9b5`]) - Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`1adb9b5`]) - Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`1adb9b5`]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index e85b843..3f01039 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -120,7 +120,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if err != nil { spin.Stop() - return fmt.Errorf("connecting to %s: %w", args[0], err) + return err } // Optional cipher suite enumeration. @@ -137,7 +137,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if scanErr != nil { spin.Stop() - return fmt.Errorf("scanning cipher suites: %w", scanErr) + return scanErr } result.CipherScan = cipherScan result.Diagnostics = append(result.Diagnostics, certkit.DiagnoseCipherScan(cipherScan)...) diff --git a/connect.go b/connect.go index 83171c2..9792aa0 100644 --- a/connect.go +++ b/connect.go @@ -983,6 +983,14 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher return cmp.Compare(a.Name, b.Name) }) + // Ensure non-omitempty slices are never nil so JSON encodes [] not null. + if versions == nil { + versions = []string{} + } + if results == nil { + results = []CipherProbeResult{} + } + return &CipherScanResult{ SupportedVersions: versions, Ciphers: results, diff --git a/connect_test.go b/connect_test.go index 8af07d8..b998ab4 100644 --- a/connect_test.go +++ b/connect_test.go @@ -3,12 +3,15 @@ package certkit import ( "bytes" "context" + "crypto/aes" + "crypto/cipher" "crypto/ecdsa" "crypto/elliptic" "crypto/rand" "crypto/tls" "crypto/x509" "crypto/x509/pkix" + "encoding/binary" "encoding/hex" "math/big" "net" @@ -1194,96 +1197,55 @@ func TestConnectTLS_CRL_AIAFetchedIssuer(t *testing.T) { func TestRateCipherSuite(t *testing.T) { t.Parallel() + // One entry per distinct code path in RateCipherSuite (T-12). tests := []struct { name string cipherID uint16 tlsVersion uint16 want CipherRating }{ - // TLS 1.3 — always excellent. + // TLS 1.3 — always good (all suites are AEAD). { - name: "TLS 1.3 AES-128-GCM", + name: "TLS 1.3 always good", cipherID: tls.TLS_AES_128_GCM_SHA256, tlsVersion: tls.VersionTLS13, want: CipherRatingGood, }, + // TLS 1.2 ECDHE + GCM — good (forward secrecy + AEAD). { - name: "TLS 1.3 AES-256-GCM", - cipherID: tls.TLS_AES_256_GCM_SHA384, - tlsVersion: tls.VersionTLS13, - want: CipherRatingGood, - }, - { - name: "TLS 1.3 CHACHA20-POLY1305", - cipherID: tls.TLS_CHACHA20_POLY1305_SHA256, - tlsVersion: tls.VersionTLS13, - want: CipherRatingGood, - }, - // TLS 1.2 ECDHE + AEAD — excellent. - { - name: "TLS 1.2 ECDHE-RSA-AES128-GCM", + name: "TLS 1.2 ECDHE+GCM good", cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, tlsVersion: tls.VersionTLS12, want: CipherRatingGood, }, + // TLS 1.2 ECDHE + ChaCha20 — good (forward secrecy + AEAD). { - name: "TLS 1.2 ECDHE-ECDSA-AES256-GCM", - cipherID: tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, - tlsVersion: tls.VersionTLS12, - want: CipherRatingGood, - }, - { - name: "TLS 1.2 ECDHE-RSA-CHACHA20-POLY1305", + name: "TLS 1.2 ECDHE+CHACHA20 good", cipherID: tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256, tlsVersion: tls.VersionTLS12, want: CipherRatingGood, }, - // TLS 1.2 ECDHE + CBC — insecure. + // TLS 1.2 ECDHE + CBC — weak (padding oracle attacks). { - name: "TLS 1.2 ECDHE-RSA-AES128-CBC-SHA256", + name: "TLS 1.2 ECDHE+CBC weak", cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, tlsVersion: tls.VersionTLS12, want: CipherRatingWeak, }, + // TLS 1.2 static RSA — weak (no forward secrecy). { - name: "TLS 1.2 ECDHE-ECDSA-AES128-CBC-SHA", - cipherID: tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, - tlsVersion: tls.VersionTLS12, - want: CipherRatingWeak, - }, - // TLS 1.2 static RSA — insecure (no forward secrecy). - { - name: "TLS 1.2 RSA-AES128-GCM", + name: "TLS 1.2 static RSA weak", cipherID: tls.TLS_RSA_WITH_AES_128_GCM_SHA256, tlsVersion: tls.VersionTLS12, want: CipherRatingWeak, }, - // Insecure cipher suites (from tls.InsecureCipherSuites). + // InsecureCipherSuites list — weak (RC4). { - name: "TLS 1.2 RSA-RC4-SHA (insecure list)", + name: "TLS 1.2 insecure list RC4 weak", cipherID: tls.TLS_RSA_WITH_RC4_128_SHA, tlsVersion: tls.VersionTLS12, want: CipherRatingWeak, }, - { - name: "TLS 1.2 RSA-3DES-EDE-CBC-SHA (insecure list)", - cipherID: tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA, - tlsVersion: tls.VersionTLS12, - want: CipherRatingWeak, - }, - { - name: "TLS 1.2 ECDHE-RSA-RC4-SHA (insecure list)", - cipherID: tls.TLS_ECDHE_RSA_WITH_RC4_128_SHA, - tlsVersion: tls.VersionTLS12, - want: CipherRatingWeak, - }, - // TLS 1.0 ECDHE + GCM — still excellent (GCM is good regardless of TLS version). - { - name: "TLS 1.0 ECDHE-RSA-AES128-GCM", - cipherID: tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, - tlsVersion: tls.VersionTLS10, - want: CipherRatingGood, - }, } for _, tt := range tests { @@ -1336,15 +1298,16 @@ func TestScanCipherSuites(t *testing.T) { t.Fatal("no ciphers detected") } - // Should detect TLS 1.3 suites (all 3). + // Should detect at least one TLS 1.3 suite (Go supports 3 standard suites; + // exact count may change if Go adds CCM support). tls13Count := 0 for _, c := range result.Ciphers { if c.Version == "TLS 1.3" { tls13Count++ } } - if tls13Count != 3 { - t.Errorf("expected 3 TLS 1.3 ciphers, got %d", tls13Count) + if tls13Count == 0 { + t.Error("expected at least one TLS 1.3 cipher, got 0") } // Should detect the two TLS 1.2 ECDHE-ECDSA-GCM ciphers we configured. @@ -1379,6 +1342,25 @@ func TestScanCipherSuites(t *testing.T) { if len(result.SupportedVersions) < 2 { t.Errorf("SupportedVersions = %v, want at least TLS 1.3 and TLS 1.2", result.SupportedVersions) } + + // Key exchange groups: Go's TLS server should accept at least X25519. + if len(result.KeyExchanges) == 0 { + t.Fatal("no key exchange groups detected") + } + kxNames := make(map[string]bool) + for _, kx := range result.KeyExchanges { + kxNames[kx.Name] = true + if kx.Name == "X25519MLKEM768" || kx.Name == "SecP256r1MLKEM768" || kx.Name == "SecP384r1MLKEM1024" { + if !kx.PostQuantum { + t.Errorf("key exchange %s should be PostQuantum", kx.Name) + } + } else if kx.PostQuantum { + t.Errorf("key exchange %s should not be PostQuantum", kx.Name) + } + } + if !kxNames["X25519"] { + t.Error("expected X25519 in key exchange results") + } } func TestScanCipherSuites_EmptyHost(t *testing.T) { @@ -1924,12 +1906,62 @@ func TestBuildQUICInitialPacket(t *testing.T) { t.Errorf("packet length = %d, want >= 1200", len(packet)) } - // Version field (bytes 1-4 after header protection) should be QUIC v1 - // before header protection. We can't check after HP, but verify the packet - // is non-empty and has the long-header high bit set (after HP, bit may vary). - // The packet should at least be well-formed and non-trivially sized. - if len(packet) == 0 { - t.Fatal("empty packet") + // Version field (bytes 1-4) is not affected by header protection. + version := binary.BigEndian.Uint32(packet[1:5]) + if version != 0x00000001 { + t.Errorf("version = 0x%08x, want 0x00000001 (QUIC v1)", version) + } + + // DCID is embedded in the unprotected header. + if int(packet[5]) != len(dcid) { + t.Errorf("DCID length = %d, want %d", packet[5], len(dcid)) + } + if !bytes.Equal(packet[6:6+len(dcid)], dcid) { + t.Error("DCID mismatch in packet header") + } + + // SCID follows DCID. + scidOffset := 6 + len(dcid) + if int(packet[scidOffset]) != len(scid) { + t.Errorf("SCID length = %d, want %d", packet[scidOffset], len(scid)) + } + if !bytes.Equal(packet[scidOffset+1:scidOffset+1+len(scid)], scid) { + t.Error("SCID mismatch in packet header") + } + + // Round-trip: derive client keys and decrypt the payload to verify + // the CRYPTO frame contains the original ClientHello. + clientKeys, _, err := deriveQUICInitialKeys(dcid) + if err != nil { + t.Fatalf("deriveQUICInitialKeys: %v", err) + } + plaintext := decryptQUICInitialForTest(t, packet, clientKeys) + + // Find CRYPTO frame (type 0x06) and verify data matches. + found := false + fpos := 0 + for fpos < len(plaintext) { + if plaintext[fpos] == 0x00 { + fpos++ + continue + } + if plaintext[fpos] != 0x06 { + break + } + fpos++ + _, vl := decodeQUICVarint(plaintext[fpos:]) + fpos += vl + dataLen, vl := decodeQUICVarint(plaintext[fpos:]) + fpos += vl + cryptoData := plaintext[fpos : fpos+int(dataLen)] + if !bytes.Equal(cryptoData, msg) { + t.Errorf("CRYPTO frame data differs from original ClientHello (%d vs %d bytes)", len(cryptoData), len(msg)) + } + found = true + break + } + if !found { + t.Error("no CRYPTO frame found in decrypted payload") } } @@ -1968,55 +2000,6 @@ func TestProbeTLS13Cipher_Concurrent(t *testing.T) { // If the race detector doesn't fire, the test passes. } -func TestScanCipherSuites_KeyExchanges(t *testing.T) { - t.Parallel() - - ca := generateTestCA(t, "KX Scan CA") - leaf := generateTestLeafCert(t, ca) - - tlsCert := tls.Certificate{ - Certificate: [][]byte{leaf.DER, ca.CertDER}, - PrivateKey: leaf.Key, - } - port := startTLSServerWithConfig(t, &tls.Config{ - Certificates: []tls.Certificate{tlsCert}, - }) - - ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) - defer cancel() - - result, err := ScanCipherSuites(ctx, ScanCipherSuitesInput{ - Host: "127.0.0.1", - Port: port, - Concurrency: 5, - }) - if err != nil { - t.Fatalf("ScanCipherSuites failed: %v", err) - } - - // Go's TLS server should accept at least X25519 and P-256. - if len(result.KeyExchanges) == 0 { - t.Fatal("no key exchange groups detected") - } - - names := make(map[string]bool) - for _, kx := range result.KeyExchanges { - names[kx.Name] = true - // Verify PostQuantum flag is set correctly. - if kx.Name == "X25519MLKEM768" || kx.Name == "SecP256r1MLKEM768" || kx.Name == "SecP384r1MLKEM1024" { - if !kx.PostQuantum { - t.Errorf("key exchange %s should be PostQuantum", kx.Name) - } - } else if kx.PostQuantum { - t.Errorf("key exchange %s should not be PostQuantum", kx.Name) - } - } - - if !names["X25519"] { - t.Error("expected X25519 in key exchange results") - } -} - // ---------- test helpers ---------- // buildTestServerHello constructs a minimal TLS 1.3 ServerHello handshake message @@ -2102,3 +2085,57 @@ func hexDecode(t *testing.T, s string) []byte { } return b } + +// decryptQUICInitialForTest removes header protection and decrypts a QUIC Initial +// packet, returning the plaintext payload. Fails the test on any error. +func decryptQUICInitialForTest(t *testing.T, packet []byte, keys quicInitialKeys) []byte { + t.Helper() + + // Parse header to find packet number offset (same structure as parseQUICInitialResponse). + pos := 5 // skip first byte + version + dcidLen := int(packet[pos]) + pos += 1 + dcidLen + scidLen := int(packet[pos]) + pos += 1 + scidLen + tokenLen, tVL := decodeQUICVarint(packet[pos:]) + pos += tVL + int(tokenLen) + _, pVL := decodeQUICVarint(packet[pos:]) + pos += pVL + pnOffset := pos + + // Remove header protection. + sample := packet[pnOffset+4 : pnOffset+4+16] + hpBlock, err := aes.NewCipher(keys.hp) + if err != nil { + t.Fatalf("HP cipher: %v", err) + } + mask := make([]byte, aes.BlockSize) + hpBlock.Encrypt(mask, sample) + packet[0] ^= mask[0] & 0x0f + pnLen := int(packet[0]&0x03) + 1 + for i := range pnLen { + packet[pnOffset+i] ^= mask[1+i] + } + + // Decrypt payload. + headerEnd := pnOffset + pnLen + block, err := aes.NewCipher(keys.key) + if err != nil { + t.Fatalf("AES cipher: %v", err) + } + gcm, err := cipher.NewGCM(block) + if err != nil { + t.Fatalf("GCM: %v", err) + } + nonce := make([]byte, 12) + copy(nonce, keys.iv) + pnBytes := packet[pnOffset:headerEnd] + for i, b := range pnBytes { + nonce[12-pnLen+i] ^= b + } + plaintext, err := gcm.Open(nil, nonce, packet[headerEnd:], packet[:headerEnd]) + if err != nil { + t.Fatalf("QUIC decrypt: %v", err) + } + return plaintext +} diff --git a/quicprobe.go b/quicprobe.go index d4f0d1b..eae419c 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -261,7 +261,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return nil, fmt.Errorf("malformed token length varint") } pos += tokenVarLen - if pos+int(tokenLen) > len(packet) { + if tokenLen > uint64(len(packet)-pos) { return nil, fmt.Errorf("packet truncated at token data") } pos += int(tokenLen) @@ -278,6 +278,9 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve pos += payloadVarLen pnOffset := pos + if payloadLen > uint64(len(packet)-pnOffset) { + return nil, fmt.Errorf("payload length %d exceeds remaining packet", payloadLen) + } payloadEnd := pnOffset + int(payloadLen) // We need the sample for header protection removal. @@ -379,27 +382,41 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve break } fpos += varLen + // Cap rangeCount to avoid CPU exhaustion on malicious packets. + if rangeCount > uint64(len(plaintext)) { + break + } + malformed := false for range rangeCount { _, varLen = decodeQUICVarint(plaintext[fpos:]) // Gap if varLen == 0 { + malformed = true break } fpos += varLen _, varLen = decodeQUICVarint(plaintext[fpos:]) // ACK Range Length if varLen == 0 { + malformed = true break } fpos += varLen } + if malformed { + break + } if frameType == 0x03 { // ACK_ECN has 3 additional varints. for range 3 { _, varLen = decodeQUICVarint(plaintext[fpos:]) if varLen == 0 { + malformed = true break } fpos += varLen } + if malformed { + break + } } continue } @@ -422,7 +439,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve } fpos += varLen - if fpos+int(dataLen) > len(plaintext) { + if dataLen > uint64(len(plaintext)-fpos) { return nil, fmt.Errorf("CRYPTO frame data truncated") } cryptoData := plaintext[fpos : fpos+int(dataLen)] From b4f962c5a42dce589acc394888074c82e76f8acd Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 01:18:31 -0500 Subject: [PATCH 08/30] docs: update changelog refs from pending to 18ed288 Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index b48f60c..ba7b434 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,11 +76,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([`pending`]) -- Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([`pending`]) -- Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([`pending`]) -- Fix double-wrapped error messages in `connect` CLI — "connecting to: connecting to:" and "scanning cipher suites: scanning cipher suites:" ([`pending`]) -- Fix `CipherScanResult` JSON encoding `supported_versions` and `ciphers` as `null` instead of `[]` when no ciphers detected ([`pending`]) +- Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([`18ed288`]) +- Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([`18ed288`]) +- Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([`18ed288`]) +- Fix double-wrapped error messages in `connect` CLI — "connecting to: connecting to:" and "scanning cipher suites: scanning cipher suites:" ([`18ed288`]) +- Fix `CipherScanResult` JSON encoding `supported_versions` and `ciphers` as `null` instead of `[]` when no ciphers detected ([`18ed288`]) - Fix backtick-quoted values in flag usage strings being consumed by pflag as type placeholders — all `--format`, `--trust-store`, `--log-level`, `--algorithm`, and `--curve` flags now display correctly in `--help` output ([#80]) - Fix `convert --json` without `-o` missing `format` field in JSON output ([#80]) - Fix data race in `TestCheckLeafCRL` — CRL bytes are now generated before starting the test HTTP server (CC-3) ([#78]) @@ -154,10 +154,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests -- Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([`pending`]) -- Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([`pending`]) -- Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([`pending`]) -- Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([`pending`]) +- Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([`18ed288`]) +- Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([`18ed288`]) +- Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([`18ed288`]) +- Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([`18ed288`]) - Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`1adb9b5`]) - Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`1adb9b5`]) - Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`1adb9b5`]) @@ -858,6 +858,7 @@ Initial release. [#76]: https://github.com/sensiblebit/certkit/pull/76 [#78]: https://github.com/sensiblebit/certkit/pull/78 [`7299fc5`]: https://github.com/sensiblebit/certkit/commit/7299fc5 +[`18ed288`]: https://github.com/sensiblebit/certkit/commit/18ed288 [`1adb9b5`]: https://github.com/sensiblebit/certkit/commit/1adb9b5 [#80]: https://github.com/sensiblebit/certkit/pull/80 [#73]: https://github.com/sensiblebit/certkit/pull/73 From 828d7f2cdb3ea2bd97851df5a86d2e125f3772d5 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 02:27:31 -0500 Subject: [PATCH 09/30] =?UTF-8?q?fix:=20address=20PR=20review=20=E2=80=94?= =?UTF-8?q?=20rating=20bug,=20error=20strings,=20test=20compaction,=20spin?= =?UTF-8?q?ner=20safety?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Rate TLS_AES_128_CCM_8_SHA256 (0x1305) as weak (IANA Not Recommended, truncated 8-byte auth tag) - Return empty OverallRating when no ciphers detected (omitempty JSON) - Guard FormatCipherScanResult against nil receiver - Tie spinner goroutine to context.Context (CC-2), make Stop idempotent with sync.Once to prevent double-close panic - Lowercase error strings per ERR-4: hello retry request, server hello, long header - Add hkdfExpandLabelInput struct per CS-5 - Remove direct tests of unexported helpers per T-11 (buildClientHelloMsg, parseServerHello, buildQUICInitialPacket, probeTLS13Cipher) — all exercised through ScanCipherSuites - Fix changelog refs: use PR [#82] instead of branch commit SHA - Fix probeTimeout comment to accurately describe context inheritance Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 10 +- cmd/certkit/connect.go | 2 +- cmd/certkit/spinner.go | 29 ++- connect.go | 31 ++- connect_test.go | 446 ----------------------------------------- quicprobe.go | 27 ++- tls13probe.go | 14 +- 7 files changed, 68 insertions(+), 491 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index ba7b434..c9e253b 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,10 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added -- Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([`7299fc5`]) -- Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([`7299fc5`]) -- Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([`7299fc5`]) -- Add QUIC/UDP cipher probing to `--ciphers` — automatically probes UDP 443 alongside TCP, shows "QUIC: not supported" when server rejects ([`7299fc5`]) +- Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([#82]) +- Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([#82]) +- Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([#82]) +- Add QUIC/UDP cipher probing to `--ciphers` — automatically probes UDP 443 alongside TCP, shows "QUIC: not supported" when server rejects ([#82]) - Auto-generate CLI flag tables in README from Cobra command definitions via `go generate` ([#80]) - Add `gendocs` pre-commit hook and CI check to verify flag tables stay in sync ([#80]) - Add global `--json` persistent flag — all commands now support JSON output; overrides `--format` when both are set ([#80]) @@ -857,10 +857,10 @@ Initial release. [#75]: https://github.com/sensiblebit/certkit/pull/75 [#76]: https://github.com/sensiblebit/certkit/pull/76 [#78]: https://github.com/sensiblebit/certkit/pull/78 -[`7299fc5`]: https://github.com/sensiblebit/certkit/commit/7299fc5 [`18ed288`]: https://github.com/sensiblebit/certkit/commit/18ed288 [`1adb9b5`]: https://github.com/sensiblebit/certkit/commit/1adb9b5 [#80]: https://github.com/sensiblebit/certkit/pull/80 +[#82]: https://github.com/sensiblebit/certkit/pull/82 [#73]: https://github.com/sensiblebit/certkit/pull/73 [#64]: https://github.com/sensiblebit/certkit/pull/64 [#63]: https://github.com/sensiblebit/certkit/pull/63 diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index 3f01039..b9487db 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -106,7 +106,7 @@ func runConnect(cmd *cobra.Command, args []string) error { } spin := newSpinner("Connecting…") - spin.Start() + spin.Start(cmd.Context()) ctx, cancel := context.WithTimeout(cmd.Context(), 10*time.Second) defer cancel() diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go index b8227d8..9c2ddc0 100644 --- a/cmd/certkit/spinner.go +++ b/cmd/certkit/spinner.go @@ -1,6 +1,7 @@ package main import ( + "context" "fmt" "os" "sync" @@ -12,11 +13,12 @@ import ( // spinner displays an animated progress indicator on stderr when the output // is a terminal. It silently does nothing when piped or redirected. type spinner struct { - mu sync.Mutex - msg string - stop chan struct{} - done chan struct{} - started bool + mu sync.Mutex + msg string + stop chan struct{} + done chan struct{} + stopOnce sync.Once + started bool } // newSpinner creates a spinner with the given message. Call Start() to begin @@ -30,15 +32,16 @@ func newSpinner(msg string) *spinner { } } -// Start begins the spinner animation in a background goroutine. -func (s *spinner) Start() { +// Start begins the spinner animation in a background goroutine. The goroutine +// is tied to ctx and will stop if the context is cancelled. +func (s *spinner) Start(ctx context.Context) { if !isatty.IsTerminal(os.Stderr.Fd()) && !isatty.IsCygwinTerminal(os.Stderr.Fd()) { close(s.done) return } s.started = true - go s.run() + go s.run(ctx) } // SetMessage updates the spinner text while it's running. @@ -48,19 +51,19 @@ func (s *spinner) SetMessage(msg string) { s.mu.Unlock() } -// Stop halts the spinner and clears the line. +// Stop halts the spinner and clears the line. Safe to call multiple times. func (s *spinner) Stop() { if !s.started { <-s.done return } - close(s.stop) + s.stopOnce.Do(func() { close(s.stop) }) <-s.done } var spinnerFrames = [...]string{"⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"} -func (s *spinner) run() { +func (s *spinner) run(ctx context.Context) { defer close(s.done) ticker := time.NewTicker(80 * time.Millisecond) @@ -80,6 +83,10 @@ func (s *spinner) run() { // Clear the spinner line. fmt.Fprintf(os.Stderr, "\r\033[K") return + case <-ctx.Done(): + // Context cancelled — clear and exit. + fmt.Fprintf(os.Stderr, "\r\033[K") + return case <-ticker.C: } } diff --git a/connect.go b/connect.go index 9792aa0..06d054c 100644 --- a/connect.go +++ b/connect.go @@ -613,7 +613,8 @@ type CipherScanResult struct { // KeyExchanges lists accepted key exchange groups (classical and post-quantum). KeyExchanges []KeyExchangeProbeResult `json:"key_exchanges,omitempty"` // OverallRating is the worst rating among all accepted ciphers. - OverallRating CipherRating `json:"overall_rating"` + // Empty when no ciphers were detected (omitted from JSON). + OverallRating CipherRating `json:"overall_rating,omitempty"` } // ScanCipherSuitesInput contains parameters for ScanCipherSuites. @@ -693,8 +694,12 @@ func kexRank(kex string) int { // RateCipherSuite returns the security rating for a cipher suite at a given TLS version. func RateCipherSuite(cipherID uint16, tlsVersion uint16) CipherRating { - // TLS 1.3 suites are always good — they only use AEAD ciphers. + // TLS 1.3 suites are all AEAD — generally good, except TLS_AES_128_CCM_8_SHA256 + // (0x1305) which uses a truncated 8-byte authentication tag and is IANA "Not Recommended". if tlsVersion == tls.VersionTLS13 { + if cipherID == 0x1305 { + return CipherRatingWeak + } return CipherRatingGood } @@ -761,9 +766,10 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher } } - // probeTimeout is the maximum time for a single probe attempt. This - // is independent of the parent context to prevent slow/stalling servers - // from blocking the entire scan. Each probe gets its own child context. + // probeTimeout is the maximum time for a single probe attempt. Each + // probe gets a child context derived from ctx, so it also inherits the + // parent's cancellation. The short timeout prevents slow/stalling + // servers from blocking the entire scan. const probeTimeout = 2 * time.Second // Probe TLS 1.3 ciphers using raw ClientHello packets. Each probe is @@ -962,11 +968,14 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher // Compute supported versions and overall rating. versionSet := make(map[string]bool) - overall := CipherRatingGood - for _, r := range results { - versionSet[r.Version] = true - if ratingRank(r.Rating) > ratingRank(overall) { - overall = r.Rating + var overall CipherRating + if len(results) > 0 { + overall = CipherRatingGood + for _, r := range results { + versionSet[r.Version] = true + if ratingRank(r.Rating) > ratingRank(overall) { + overall = r.Rating + } } } @@ -1167,7 +1176,7 @@ func kexLabel(kex string) string { // FormatCipherScanResult formats the cipher suite list as human-readable text. func FormatCipherScanResult(r *CipherScanResult) string { - if len(r.Ciphers) == 0 { + if r == nil || len(r.Ciphers) == 0 { return "" } diff --git a/connect_test.go b/connect_test.go index b998ab4..c71d9ff 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1,24 +1,18 @@ package certkit import ( - "bytes" "context" - "crypto/aes" - "crypto/cipher" "crypto/ecdsa" "crypto/elliptic" "crypto/rand" "crypto/tls" "crypto/x509" "crypto/x509/pkix" - "encoding/binary" - "encoding/hex" "math/big" "net" "net/http" "net/http/httptest" "strings" - "sync" "sync/atomic" "testing" "time" @@ -1699,443 +1693,3 @@ func TestConnectTLS_CRL_DuplicateLeafInChain(t *testing.T) { t.Errorf("CRL.Detail = %q, want substring %q", result.CRL.Detail, revokedSerial.Text(16)) } } - -func TestBuildClientHello(t *testing.T) { - t.Parallel() - - t.Run("TCP mode", func(t *testing.T) { - t.Parallel() - msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: "example.com", - cipherSuite: 0x1301, // TLS_AES_128_GCM_SHA256 - groupID: tls.X25519, - }) - if err != nil { - t.Fatalf("buildClientHelloMsg failed: %v", err) - } - - // Handshake type must be ClientHello (0x01). - if msg[0] != 0x01 { - t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) - } - - // Handshake length (3 bytes, big-endian) must match actual body length. - handshakeLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) - if handshakeLen != len(msg)-4 { - t.Errorf("handshake length = %d, want %d", handshakeLen, len(msg)-4) - } - - // Legacy version at body[0:2] must be TLS 1.2 (0x0303). - if msg[4] != 0x03 || msg[5] != 0x03 { - t.Errorf("legacy version = 0x%02x%02x, want 0x0303", msg[4], msg[5]) - } - - // Session ID length at body[34] — TCP mode uses 32-byte session ID. - sessionIDLen := int(msg[4+34]) - if sessionIDLen != 32 { - t.Errorf("session ID length = %d, want 32", sessionIDLen) - } - - // Cipher suite list starts after session ID. - csOffset := 4 + 35 + sessionIDLen - csListLen := int(msg[csOffset])<<8 | int(msg[csOffset+1]) - if csListLen != 2 { - t.Errorf("cipher suite list length = %d, want 2 (single cipher)", csListLen) - } - csID := uint16(msg[csOffset+2])<<8 | uint16(msg[csOffset+3]) - if csID != 0x1301 { - t.Errorf("cipher suite = 0x%04x, want 0x1301", csID) - } - }) - - t.Run("QUIC mode with ALPN", func(t *testing.T) { - t.Parallel() - msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: "example.com", - cipherSuite: 0x1301, - groupID: tls.X25519, - alpn: []string{"h3"}, - quic: true, - }) - if err != nil { - t.Fatalf("buildClientHelloMsg with ALPN failed: %v", err) - } - - // Handshake type must be ClientHello (0x01). - if msg[0] != 0x01 { - t.Errorf("handshake type = 0x%02x, want 0x01", msg[0]) - } - - // QUIC mode: session ID must be empty (RFC 9001 §8.4). - sessionIDLen := int(msg[4+34]) - if sessionIDLen != 0 { - t.Errorf("QUIC session ID length = %d, want 0", sessionIDLen) - } - - // Message must contain the ALPN extension with "h3". - if !bytes.Contains(msg, []byte("h3")) { - t.Error("ClientHello missing ALPN 'h3'") - } - }) -} - -func TestParseServerHello(t *testing.T) { - t.Parallel() - - tests := []struct { - name string - data []byte - wantCipher uint16 - wantVersion uint16 - wantErr string - }{ - { - name: "valid TLS 1.3 ServerHello", - data: buildTestServerHello(0x1301, 0x0304), - wantCipher: 0x1301, - wantVersion: 0x0304, - }, - { - name: "valid TLS 1.2 ServerHello (no supported_versions ext)", - data: buildTestServerHello12(0xc02f), - wantCipher: 0xc02f, - wantVersion: 0x0303, - }, - { - name: "truncated input", - data: []byte{0x02, 0x00}, - wantErr: "too short", - }, - { - name: "wrong handshake type", - data: append([]byte{0x0b, 0x00, 0x00, 0x04}, make([]byte, 4)...), - wantErr: "unexpected handshake type", - }, - { - name: "HelloRetryRequest (HRR sentinel random)", - data: buildTestServerHelloHRR(0x1301), - wantErr: "HelloRetryRequest", - }, - { - name: "oversized session ID length causes truncation", - // Handshake header(4) + version(2) + random(32) + sessionIDLen(1) = 39 bytes body. - // sessionIDLen=200 causes pos to jump past body, caught at cipher suite bounds check. - data: func() []byte { - body := make([]byte, 35) - body[0], body[1] = 0x03, 0x03 // version - body[34] = 200 // sessionIDLen far exceeds body - msg := []byte{0x02} - msg = appendUint24(msg, uint32(len(body))) - msg = append(msg, body...) - return msg - }(), - wantErr: "truncated at session ID", - }, - { - name: "truncated at compression method", - // Body: version(2) + random(32) + sessionIDLen(1,val=0) + cipher(2) = 37 bytes. - // No compression method byte. - data: func() []byte { - body := make([]byte, 37) - body[0], body[1] = 0x03, 0x03 // version - body[34] = 0 // sessionIDLen = 0 - body[35], body[36] = 0x13, 0x01 - msg := []byte{0x02} - msg = appendUint24(msg, uint32(len(body))) - msg = append(msg, body...) - return msg - }(), - wantErr: "truncated at compression method", - }, - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - t.Parallel() - result, err := parseServerHello(tt.data) - if tt.wantErr != "" { - if err == nil { - t.Fatalf("expected error containing %q, got nil", tt.wantErr) - } - if !strings.Contains(err.Error(), tt.wantErr) { - t.Errorf("error = %q, want substring %q", err, tt.wantErr) - } - return - } - if err != nil { - t.Fatalf("unexpected error: %v", err) - } - if result.cipherSuite != tt.wantCipher { - t.Errorf("cipherSuite = 0x%04x, want 0x%04x", result.cipherSuite, tt.wantCipher) - } - if result.version != tt.wantVersion { - t.Errorf("version = 0x%04x, want 0x%04x", result.version, tt.wantVersion) - } - }) - } -} - -func TestBuildQUICInitialPacket(t *testing.T) { - t.Parallel() - - msg, err := buildClientHelloMsg(clientHelloInput{ - serverName: "example.com", - cipherSuite: 0x1301, - groupID: tls.X25519, - alpn: []string{"h3"}, - quic: true, - }) - if err != nil { - t.Fatalf("buildClientHelloMsg failed: %v", err) - } - - dcid := hexDecode(t, "0102030405060708") - scid := hexDecode(t, "0807060504030201") - - packet, err := buildQUICInitialPacket(quicInitialPacketInput{ - clientHello: msg, - dcid: dcid, - scid: scid, - }) - if err != nil { - t.Fatalf("buildQUICInitialPacket failed: %v", err) - } - - // Packet must be at least 1200 bytes (QUIC minimum datagram size). - if len(packet) < 1200 { - t.Errorf("packet length = %d, want >= 1200", len(packet)) - } - - // Version field (bytes 1-4) is not affected by header protection. - version := binary.BigEndian.Uint32(packet[1:5]) - if version != 0x00000001 { - t.Errorf("version = 0x%08x, want 0x00000001 (QUIC v1)", version) - } - - // DCID is embedded in the unprotected header. - if int(packet[5]) != len(dcid) { - t.Errorf("DCID length = %d, want %d", packet[5], len(dcid)) - } - if !bytes.Equal(packet[6:6+len(dcid)], dcid) { - t.Error("DCID mismatch in packet header") - } - - // SCID follows DCID. - scidOffset := 6 + len(dcid) - if int(packet[scidOffset]) != len(scid) { - t.Errorf("SCID length = %d, want %d", packet[scidOffset], len(scid)) - } - if !bytes.Equal(packet[scidOffset+1:scidOffset+1+len(scid)], scid) { - t.Error("SCID mismatch in packet header") - } - - // Round-trip: derive client keys and decrypt the payload to verify - // the CRYPTO frame contains the original ClientHello. - clientKeys, _, err := deriveQUICInitialKeys(dcid) - if err != nil { - t.Fatalf("deriveQUICInitialKeys: %v", err) - } - plaintext := decryptQUICInitialForTest(t, packet, clientKeys) - - // Find CRYPTO frame (type 0x06) and verify data matches. - found := false - fpos := 0 - for fpos < len(plaintext) { - if plaintext[fpos] == 0x00 { - fpos++ - continue - } - if plaintext[fpos] != 0x06 { - break - } - fpos++ - _, vl := decodeQUICVarint(plaintext[fpos:]) - fpos += vl - dataLen, vl := decodeQUICVarint(plaintext[fpos:]) - fpos += vl - cryptoData := plaintext[fpos : fpos+int(dataLen)] - if !bytes.Equal(cryptoData, msg) { - t.Errorf("CRYPTO frame data differs from original ClientHello (%d vs %d bytes)", len(cryptoData), len(msg)) - } - found = true - break - } - if !found { - t.Error("no CRYPTO frame found in decrypted payload") - } -} - -func TestProbeTLS13Cipher_Concurrent(t *testing.T) { - t.Parallel() - - // Verify that concurrent raw probes don't race. Each probe is fully - // isolated with its own TCP connection and packet — no shared state. - - ca := generateTestCA(t, "Raw Probe CA") - leaf := generateTestLeafCert(t, ca) - - tlsCert := tls.Certificate{ - Certificate: [][]byte{leaf.DER, ca.CertDER}, - PrivateKey: leaf.Key, - } - port := startTLSServerWithConfig(t, &tls.Config{ - Certificates: []tls.Certificate{tlsCert}, - }) - addr := net.JoinHostPort("127.0.0.1", port) - - ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second) - defer cancel() - - // Run 50 concurrent probes against 3 different cipher suites. - var wg sync.WaitGroup - for i := range 50 { - wg.Add(1) - go func(idx int) { - defer wg.Done() - cipherID := tls13CipherSuites[idx%len(tls13CipherSuites)] - probeTLS13Cipher(ctx, cipherProbeInput{addr: addr, serverName: "127.0.0.1", cipherID: cipherID}) - }(i) - } - wg.Wait() - // If the race detector doesn't fire, the test passes. -} - -// ---------- test helpers ---------- - -// buildTestServerHello constructs a minimal TLS 1.3 ServerHello handshake message -// with the given cipher suite and a supported_versions extension. -func buildTestServerHello(cipherSuite uint16, version uint16) []byte { - // ServerHello body: version(2) + random(32) + session_id(1+32) + cipher(2) + compression(1) + extensions - var body []byte - body = append(body, 0x03, 0x03) // legacy version TLS 1.2 - body = append(body, make([]byte, 32)...) // random - body = append(body, 32) // session ID length - body = append(body, make([]byte, 32)...) // session ID - body = appendUint16(body, cipherSuite) - body = append(body, 0x00) // compression: null - - // Extensions: supported_versions. - var exts []byte - exts = appendUint16(exts, 0x002b) // supported_versions - exts = appendUint16(exts, 2) // length - exts = appendUint16(exts, version) - body = appendUint16(body, uint16(len(exts))) - body = append(body, exts...) - - msg := []byte{0x02} // ServerHello - msg = appendUint24(msg, uint32(len(body))) - msg = append(msg, body...) - return msg -} - -// buildTestServerHelloHRR constructs a ServerHello with the HelloRetryRequest -// sentinel random value (RFC 8446 §4.1.3), indicating the server doesn't -// support the offered key exchange group. -func buildTestServerHelloHRR(cipherSuite uint16) []byte { - var body []byte - body = append(body, 0x03, 0x03) // legacy version TLS 1.2 - // HRR sentinel random (RFC 8446 §4.1.3). - body = append(body, - 0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11, - 0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91, - 0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E, - 0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C, - ) - body = append(body, 32) // session ID length - body = append(body, make([]byte, 32)...) // session ID - body = appendUint16(body, cipherSuite) - body = append(body, 0x00) // compression: null - - // Extensions: supported_versions with TLS 1.3. - var exts []byte - exts = appendUint16(exts, 0x002b) // supported_versions - exts = appendUint16(exts, 2) // length - exts = appendUint16(exts, 0x0304) // TLS 1.3 - body = appendUint16(body, uint16(len(exts))) - body = append(body, exts...) - - msg := []byte{0x02} // ServerHello - msg = appendUint24(msg, uint32(len(body))) - msg = append(msg, body...) - return msg -} - -// buildTestServerHello12 constructs a minimal TLS 1.2 ServerHello (no supported_versions ext). -func buildTestServerHello12(cipherSuite uint16) []byte { - var body []byte - body = append(body, 0x03, 0x03) // legacy version TLS 1.2 - body = append(body, make([]byte, 32)...) // random - body = append(body, 32) // session ID length - body = append(body, make([]byte, 32)...) // session ID - body = appendUint16(body, cipherSuite) - body = append(body, 0x00) // compression: null - - msg := []byte{0x02} // ServerHello - msg = appendUint24(msg, uint32(len(body))) - msg = append(msg, body...) - return msg -} - -// hexDecode decodes a hex string, failing the test on error. -func hexDecode(t *testing.T, s string) []byte { - t.Helper() - b, err := hex.DecodeString(s) - if err != nil { - t.Fatalf("hex decode %q: %v", s, err) - } - return b -} - -// decryptQUICInitialForTest removes header protection and decrypts a QUIC Initial -// packet, returning the plaintext payload. Fails the test on any error. -func decryptQUICInitialForTest(t *testing.T, packet []byte, keys quicInitialKeys) []byte { - t.Helper() - - // Parse header to find packet number offset (same structure as parseQUICInitialResponse). - pos := 5 // skip first byte + version - dcidLen := int(packet[pos]) - pos += 1 + dcidLen - scidLen := int(packet[pos]) - pos += 1 + scidLen - tokenLen, tVL := decodeQUICVarint(packet[pos:]) - pos += tVL + int(tokenLen) - _, pVL := decodeQUICVarint(packet[pos:]) - pos += pVL - pnOffset := pos - - // Remove header protection. - sample := packet[pnOffset+4 : pnOffset+4+16] - hpBlock, err := aes.NewCipher(keys.hp) - if err != nil { - t.Fatalf("HP cipher: %v", err) - } - mask := make([]byte, aes.BlockSize) - hpBlock.Encrypt(mask, sample) - packet[0] ^= mask[0] & 0x0f - pnLen := int(packet[0]&0x03) + 1 - for i := range pnLen { - packet[pnOffset+i] ^= mask[1+i] - } - - // Decrypt payload. - headerEnd := pnOffset + pnLen - block, err := aes.NewCipher(keys.key) - if err != nil { - t.Fatalf("AES cipher: %v", err) - } - gcm, err := cipher.NewGCM(block) - if err != nil { - t.Fatalf("GCM: %v", err) - } - nonce := make([]byte, 12) - copy(nonce, keys.iv) - pnBytes := packet[pnOffset:headerEnd] - for i, b := range pnBytes { - nonce[12-pnLen+i] ^= b - } - plaintext, err := gcm.Open(nil, nonce, packet[headerEnd:], packet[:headerEnd]) - if err != nil { - t.Fatalf("QUIC decrypt: %v", err) - } - return plaintext -} diff --git a/quicprobe.go b/quicprobe.go index eae419c..75a62b5 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -45,7 +45,7 @@ func deriveQUICInitialKeys(dcid []byte) (client, server quicInitialKeys, err err return client, server, fmt.Errorf("extracting initial secret: %w", err) } - clientSecret, err := hkdfExpandLabel(initialSecret, "client in", 32) + clientSecret, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: initialSecret, label: "client in", length: 32}) if err != nil { return client, server, fmt.Errorf("deriving client secret: %w", err) } @@ -54,7 +54,7 @@ func deriveQUICInitialKeys(dcid []byte) (client, server quicInitialKeys, err err return client, server, fmt.Errorf("deriving client keys: %w", err) } - serverSecret, err := hkdfExpandLabel(initialSecret, "server in", 32) + serverSecret, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: initialSecret, label: "server in", length: 32}) if err != nil { return client, server, fmt.Errorf("deriving server secret: %w", err) } @@ -68,34 +68,41 @@ func deriveQUICInitialKeys(dcid []byte) (client, server quicInitialKeys, err err // deriveTrafficKeys derives key, IV, and HP key from a traffic secret. func deriveTrafficKeys(secret []byte) (quicInitialKeys, error) { - key, err := hkdfExpandLabel(secret, "quic key", 16) + key, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic key", length: 16}) if err != nil { return quicInitialKeys{}, err } - iv, err := hkdfExpandLabel(secret, "quic iv", 12) + iv, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic iv", length: 12}) if err != nil { return quicInitialKeys{}, err } - hp, err := hkdfExpandLabel(secret, "quic hp", 16) + hp, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic hp", length: 16}) if err != nil { return quicInitialKeys{}, err } return quicInitialKeys{key: key, iv: iv, hp: hp}, nil } +// hkdfExpandLabelInput contains parameters for HKDF-Expand-Label. +type hkdfExpandLabelInput struct { + secret []byte + label string + length int +} + // hkdfExpandLabel implements TLS 1.3 HKDF-Expand-Label (RFC 8446 §7.1). // The label is prefixed with "tls13 " as required by the spec. -func hkdfExpandLabel(secret []byte, label string, length int) ([]byte, error) { - fullLabel := "tls13 " + label +func hkdfExpandLabel(input hkdfExpandLabelInput) ([]byte, error) { + fullLabel := "tls13 " + input.label // Build HkdfLabel struct: uint16 length + opaque label<7..255> + opaque context<0..255> var info []byte - info = appendUint16(info, uint16(length)) + info = appendUint16(info, uint16(input.length)) info = append(info, byte(len(fullLabel))) info = append(info, []byte(fullLabel)...) info = append(info, 0) // empty context - return hkdf.Expand(sha256.New, secret, string(info), length) + return hkdf.Expand(sha256.New, input.secret, string(info), input.length) } // quicInitialPacketInput contains parameters for building a QUIC Initial packet. @@ -218,7 +225,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve // Check it's a Long Header Initial packet. firstByte := packet[0] if firstByte&0x80 == 0 { - return nil, fmt.Errorf("not a Long Header packet") + return nil, fmt.Errorf("not a long header packet") } // Remove header protection first. diff --git a/tls13probe.go b/tls13probe.go index 50ed0a9..fbb91ed 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -67,7 +67,7 @@ var errAlertReceived = errors.New("TLS alert received") // HelloRetryRequest instead of a real ServerHello. Per RFC 8446 §4.1.3, an HRR // is a ServerHello with a specific synthetic random value. It means the server // supports TLS 1.3 but not the offered key exchange group. -var errHelloRetryRequest = errors.New("HelloRetryRequest received (group not supported)") +var errHelloRetryRequest = errors.New("hello retry request received, group not supported") // hrrSentinel is the synthetic random value that distinguishes a // HelloRetryRequest from a real ServerHello (RFC 8446 §4.1.3). @@ -288,18 +288,18 @@ func parseServerHello(data []byte) (*serverHelloResult, error) { handshakeLen := int(data[1])<<16 | int(data[2])<<8 | int(data[3]) if handshakeType != 0x02 { - return nil, fmt.Errorf("unexpected handshake type: 0x%02x (expected ServerHello 0x02)", handshakeType) + return nil, fmt.Errorf("unexpected handshake type: 0x%02x, expected server hello 0x02", handshakeType) } if len(data) < 4+handshakeLen { - return nil, fmt.Errorf("ServerHello truncated: need %d bytes, have %d", 4+handshakeLen, len(data)) + return nil, fmt.Errorf("server hello truncated: need %d bytes, have %d", 4+handshakeLen, len(data)) } body := data[4 : 4+handshakeLen] // ServerHello body: version(2) + random(32) + session_id_len(1) + ... if len(body) < 35 { - return nil, fmt.Errorf("ServerHello body too short: %d bytes", len(body)) + return nil, fmt.Errorf("server hello body too short: %d bytes", len(body)) } // Check for HelloRetryRequest (RFC 8446 §4.1.3): a ServerHello with the @@ -317,20 +317,20 @@ func parseServerHello(data []byte) (*serverHelloResult, error) { sessionIDLen := int(body[pos]) pos++ if pos+sessionIDLen > len(body) { - return nil, fmt.Errorf("ServerHello truncated at session ID") + return nil, fmt.Errorf("server hello truncated at session ID") } pos += sessionIDLen // Cipher suite (2 bytes). if pos+2 > len(body) { - return nil, fmt.Errorf("ServerHello truncated at cipher suite") + return nil, fmt.Errorf("server hello truncated at cipher suite") } cipherSuite := binary.BigEndian.Uint16(body[pos : pos+2]) pos += 2 // Compression method (1 byte). if pos+1 > len(body) { - return nil, fmt.Errorf("ServerHello truncated at compression method") + return nil, fmt.Errorf("server hello truncated at compression method") } pos++ From 1e9ebabf4d83239d395ed422e8ad995856eb6dd6 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 03:40:32 -0500 Subject: [PATCH 10/30] =?UTF-8?q?fix:=20address=20remaining=20PR=20review?= =?UTF-8?q?=20=E2=80=94=20test=20coverage,=20changelog=20refs,=20spinner?= =?UTF-8?q?=20safety?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Add TLS_AES_128_CCM_8_SHA256 (0x1305) → CipherRatingWeak test case covering the only TLS 1.3 cipher rated weak (T-12) - Replace in-branch commit SHAs (18ed288, 1adb9b5) with PR ref [#82] so changelog links survive squash merge (CL-3/CL-4) - Move go-mod-update and npm-update pre-commit hooks to stages: [manual] to avoid unexpected dependency churn on every commit - Guard spinner.Start() with sync.Once for idempotent calls - Add slog.Debug for QUIC PADDING/PING frame skips (ERR-5) - Document X25519-only limitation in probeTLS13Cipher comment Co-Authored-By: Claude Opus 4.6 --- .pre-commit-config.yaml | 2 ++ CHANGELOG.md | 36 +++++++++++++++++------------------- cmd/certkit/spinner.go | 30 +++++++++++++++++------------- connect_test.go | 11 +++++++++-- quicprobe.go | 5 +++-- tls13probe.go | 5 +++++ 6 files changed, 53 insertions(+), 36 deletions(-) diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml index 1e4a5d6..db6ed30 100644 --- a/.pre-commit-config.yaml +++ b/.pre-commit-config.yaml @@ -29,6 +29,7 @@ repos: language: system files: \.go$ pass_filenames: false + stages: [manual] - id: npm-update name: npm update @@ -36,6 +37,7 @@ repos: language: system files: ^web/ pass_filenames: false + stages: [manual] # ── Docs ── - repo: local diff --git a/CHANGELOG.md b/CHANGELOG.md index c9e253b..abef16f 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -57,9 +57,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed -- Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([`1adb9b5`]) -- Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([`1adb9b5`]) -- Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([`1adb9b5`]) +- Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([#82]) +- Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) +- Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([#82]) - **Breaking:** Rename `csr --cert` flag to `--from-cert` for clarity — avoids confusion with certificate file arguments in other commands ([#80]) - **Breaking:** `connect` JSON `sha256_fingerprint` format changed from lowercase hex to colon-separated uppercase hex for CLI-4 consistency with `inspect` and `sha1_fingerprint` ([#80]) - **Breaking:** Rename `CRLCheckResult.DistributionPoint` to `CRLCheckResult.URL` (JSON: `url`) and `OCSPResult.ResponderURL` to `OCSPResult.URL` (JSON: `url`) — consistent field name for the checked endpoint across both revocation types (CLI-4) ([#78]) @@ -76,11 +76,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([`18ed288`]) -- Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([`18ed288`]) -- Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([`18ed288`]) -- Fix double-wrapped error messages in `connect` CLI — "connecting to: connecting to:" and "scanning cipher suites: scanning cipher suites:" ([`18ed288`]) -- Fix `CipherScanResult` JSON encoding `supported_versions` and `ciphers` as `null` instead of `[]` when no ciphers detected ([`18ed288`]) +- Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) +- Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) +- Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) +- Fix double-wrapped error messages in `connect` CLI — "connecting to: connecting to:" and "scanning cipher suites: scanning cipher suites:" ([#82]) +- Fix `CipherScanResult` JSON encoding `supported_versions` and `ciphers` as `null` instead of `[]` when no ciphers detected ([#82]) - Fix backtick-quoted values in flag usage strings being consumed by pflag as type placeholders — all `--format`, `--trust-store`, `--log-level`, `--algorithm`, and `--curve` flags now display correctly in `--help` output ([#80]) - Fix `convert --json` without `-o` missing `format` field in JSON output ([#80]) - Fix data race in `TestCheckLeafCRL` — CRL bytes are now generated before starting the test HTTP server (CC-3) ([#78]) @@ -154,15 +154,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests -- Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([`18ed288`]) -- Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([`18ed288`]) -- Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([`18ed288`]) -- Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([`18ed288`]) -- Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([`1adb9b5`]) -- Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([`1adb9b5`]) -- Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([`1adb9b5`]) -- Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([`1adb9b5`]) -- Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([`1adb9b5`]) +- Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([#82]) +- Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([#82]) +- Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([#82]) +- Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([#82]) +- Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([#82]) +- Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([#82]) +- Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([#82]) +- Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([#82]) +- Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([#82]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) @@ -857,8 +857,6 @@ Initial release. [#75]: https://github.com/sensiblebit/certkit/pull/75 [#76]: https://github.com/sensiblebit/certkit/pull/76 [#78]: https://github.com/sensiblebit/certkit/pull/78 -[`18ed288`]: https://github.com/sensiblebit/certkit/commit/18ed288 -[`1adb9b5`]: https://github.com/sensiblebit/certkit/commit/1adb9b5 [#80]: https://github.com/sensiblebit/certkit/pull/80 [#82]: https://github.com/sensiblebit/certkit/pull/82 [#73]: https://github.com/sensiblebit/certkit/pull/73 diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go index 9c2ddc0..827e0ea 100644 --- a/cmd/certkit/spinner.go +++ b/cmd/certkit/spinner.go @@ -13,12 +13,13 @@ import ( // spinner displays an animated progress indicator on stderr when the output // is a terminal. It silently does nothing when piped or redirected. type spinner struct { - mu sync.Mutex - msg string - stop chan struct{} - done chan struct{} - stopOnce sync.Once - started bool + mu sync.Mutex + msg string + stop chan struct{} + done chan struct{} + startOnce sync.Once + stopOnce sync.Once + started bool } // newSpinner creates a spinner with the given message. Call Start() to begin @@ -33,15 +34,18 @@ func newSpinner(msg string) *spinner { } // Start begins the spinner animation in a background goroutine. The goroutine -// is tied to ctx and will stop if the context is cancelled. +// is tied to ctx and will stop if the context is cancelled. Safe to call +// multiple times — only the first call has any effect. func (s *spinner) Start(ctx context.Context) { - if !isatty.IsTerminal(os.Stderr.Fd()) && !isatty.IsCygwinTerminal(os.Stderr.Fd()) { - close(s.done) - return - } + s.startOnce.Do(func() { + if !isatty.IsTerminal(os.Stderr.Fd()) && !isatty.IsCygwinTerminal(os.Stderr.Fd()) { + close(s.done) + return + } - s.started = true - go s.run(ctx) + s.started = true + go s.run(ctx) + }) } // SetMessage updates the spinner text while it's running. diff --git a/connect_test.go b/connect_test.go index c71d9ff..24429f4 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1198,13 +1198,20 @@ func TestRateCipherSuite(t *testing.T) { tlsVersion uint16 want CipherRating }{ - // TLS 1.3 — always good (all suites are AEAD). + // TLS 1.3 — generally good (all suites are AEAD). { - name: "TLS 1.3 always good", + name: "TLS 1.3 good", cipherID: tls.TLS_AES_128_GCM_SHA256, tlsVersion: tls.VersionTLS13, want: CipherRatingGood, }, + // TLS 1.3 CCM_8 — weak (truncated 8-byte auth tag, IANA "Not Recommended"). + { + name: "TLS 1.3 CCM_8 weak", + cipherID: 0x1305, + tlsVersion: tls.VersionTLS13, + want: CipherRatingWeak, + }, // TLS 1.2 ECDHE + GCM — good (forward secrecy + AEAD). { name: "TLS 1.2 ECDHE+GCM good", diff --git a/quicprobe.go b/quicprobe.go index 75a62b5..ea3ac14 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -19,6 +19,7 @@ import ( "encoding/binary" "fmt" "io" + "log/slog" "net" ) @@ -357,12 +358,12 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve for fpos < len(plaintext) { frameType := plaintext[fpos] if frameType == 0x00 { - // PADDING frame — skip. + slog.Debug("skipping QUIC PADDING frame") fpos++ continue } if frameType == 0x01 { - // PING frame — skip. + slog.Debug("skipping QUIC PING frame") fpos++ continue } diff --git a/tls13probe.go b/tls13probe.go index fbb91ed..729d550 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -381,6 +381,11 @@ type cipherProbeInput struct { // probeTLS13Cipher attempts a raw TLS 1.3 ClientHello with a single cipher // suite and returns true if the server accepts it. Each call is fully isolated // with no shared state — safe for concurrent use from multiple goroutines. +// +// The key share uses X25519 only. Servers that support TLS 1.3 but reject +// X25519 will trigger a HelloRetryRequest, causing this probe to return false. +// In practice this is extremely rare — X25519 is mandatory in modern browsers +// and required by RFC 8446 implementations. func probeTLS13Cipher(ctx context.Context, input cipherProbeInput) bool { dialer := &net.Dialer{} conn, err := dialer.DialContext(ctx, "tcp", input.addr) From 7a155c3c3006367126a8ef20332f86cacd480739 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 04:50:32 -0500 Subject: [PATCH 11/30] fix: use slices.Concat, show empty cipher message, strengthen tests - Use slices.Concat instead of append for cipher suite slice concatenation to prevent potential mutation of stdlib return value - Show "Cipher suites: none detected" when scan finds no supported suites instead of silent empty output - Add nil and empty-ciphers test cases to TestFormatCipherScanResult with exact-match assertion (previously asserted nothing) - Consolidate startTLSServer to delegate to startTLSServerWithConfig, eliminating duplicated accept-loop code Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 4 ++++ connect.go | 7 +++++-- connect_test.go | 16 ++++++++++++++-- testhelpers_test.go | 38 +++++--------------------------------- 4 files changed, 28 insertions(+), 37 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index abef16f..a6af5a9 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,6 +76,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed +- Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([`pending`]) +- Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([`pending`]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) @@ -160,6 +162,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([#82]) - Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([#82]) - Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([#82]) +- Add nil and empty-ciphers test cases to `TestFormatCipherScanResult` — previously the empty case asserted nothing ([`pending`]) +- Consolidate `startTLSServer` to delegate to `startTLSServerWithConfig` — eliminates duplicated accept-loop code ([`pending`]) - Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([#82]) - Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([#82]) - Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([#82]) diff --git a/connect.go b/connect.go index 06d054c..52e5906 100644 --- a/connect.go +++ b/connect.go @@ -811,7 +811,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher version uint16 } var tasks []probeTask - allSuites := append(tls.CipherSuites(), tls.InsecureCipherSuites()...) + allSuites := slices.Concat(tls.CipherSuites(), tls.InsecureCipherSuites()) for _, cs := range allSuites { for _, v := range cs.SupportedVersions { if v >= tls.VersionTLS10 && v <= tls.VersionTLS12 { @@ -1176,9 +1176,12 @@ func kexLabel(kex string) string { // FormatCipherScanResult formats the cipher suite list as human-readable text. func FormatCipherScanResult(r *CipherScanResult) string { - if r == nil || len(r.Ciphers) == 0 { + if r == nil { return "" } + if len(r.Ciphers) == 0 { + return "\nCipher suites: none detected\n" + } var out strings.Builder fmt.Fprintf(&out, "\nCipher suites (%d supported):\n", len(r.Ciphers)) diff --git a/connect_test.go b/connect_test.go index 24429f4..7b11446 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1378,14 +1378,20 @@ func TestFormatCipherScanResult(t *testing.T) { tests := []struct { name string result *CipherScanResult + wantExact string // if non-empty, assert exact match instead of substring checks wantStrings []string }{ { - name: "empty results — no output", + name: "nil result — no output", + result: nil, + wantExact: "", + }, + { + name: "empty ciphers — none detected", result: &CipherScanResult{ Ciphers: nil, }, - wantStrings: nil, // empty string, nothing to check + wantStrings: []string{"none detected"}, }, { name: "mixed ratings with kex subgroups", @@ -1473,6 +1479,12 @@ func TestFormatCipherScanResult(t *testing.T) { t.Run(tt.name, func(t *testing.T) { t.Parallel() output := FormatCipherScanResult(tt.result) + if tt.wantStrings == nil { + if output != tt.wantExact { + t.Errorf("want exact %q, got %q", tt.wantExact, output) + } + return + } for _, want := range tt.wantStrings { if !strings.Contains(output, want) { t.Errorf("output missing %q\ngot:\n%s", want, output) diff --git a/testhelpers_test.go b/testhelpers_test.go index 2ef5455..0767e93 100644 --- a/testhelpers_test.go +++ b/testhelpers_test.go @@ -396,40 +396,12 @@ func generateTestLeafCert(t *testing.T, ca *testCA, opts ...testLeafOption) *tes // and private key. Returns the listener port. The server is stopped via t.Cleanup. func startTLSServer(t *testing.T, certChain [][]byte, key *ecdsa.PrivateKey) string { t.Helper() - tlsCert := tls.Certificate{ - Certificate: certChain, - PrivateKey: key, - } - listener, err := tls.Listen("tcp", "127.0.0.1:0", &tls.Config{ - Certificates: []tls.Certificate{tlsCert}, + return startTLSServerWithConfig(t, &tls.Config{ + Certificates: []tls.Certificate{{ + Certificate: certChain, + PrivateKey: key, + }}, }) - if err != nil { - t.Fatal(err) - } - t.Cleanup(func() { _ = listener.Close() }) - - go func() { - for { - conn, err := listener.Accept() - if err != nil { - return - } - if tlsConn, ok := conn.(*tls.Conn); ok { - if err := tlsConn.Handshake(); err != nil { - slog.Debug("startTLSServer: handshake error (expected during test teardown)", "error", err) - } - } - if err := conn.Close(); err != nil { - slog.Debug("startTLSServer: connection close error", "error", err) - } - } - }() - - _, port, err := net.SplitHostPort(listener.Addr().String()) - if err != nil { - t.Fatal(err) - } - return port } // startTLSServerWithConfig starts a TLS server with the given tls.Config. From e926fa035e9b8ba01ae5d336ab8b01ba0323f282 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 04:51:21 -0500 Subject: [PATCH 12/30] docs: update changelog refs from pending to 7a155c3 Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index a6af5a9..a1f873c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,8 +76,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([`pending`]) -- Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([`pending`]) +- Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([`7a155c3`]) +- Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([`7a155c3`]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) @@ -162,8 +162,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([#82]) - Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([#82]) - Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([#82]) -- Add nil and empty-ciphers test cases to `TestFormatCipherScanResult` — previously the empty case asserted nothing ([`pending`]) -- Consolidate `startTLSServer` to delegate to `startTLSServerWithConfig` — eliminates duplicated accept-loop code ([`pending`]) +- Add nil and empty-ciphers test cases to `TestFormatCipherScanResult` — previously the empty case asserted nothing ([`7a155c3`]) +- Consolidate `startTLSServer` to delegate to `startTLSServerWithConfig` — eliminates duplicated accept-loop code ([`7a155c3`]) - Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([#82]) - Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([#82]) - Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([#82]) @@ -798,6 +798,7 @@ Initial release. [0.1.2]: https://github.com/sensiblebit/certkit/compare/v0.1.1...v0.1.2 [0.1.1]: https://github.com/sensiblebit/certkit/compare/v0.1.0...v0.1.1 [0.1.0]: https://github.com/sensiblebit/certkit/releases/tag/v0.1.0 +[`7a155c3`]: https://github.com/sensiblebit/certkit/commit/7a155c3 [`2693116`]: https://github.com/sensiblebit/certkit/commit/2693116 [`84c4edf`]: https://github.com/sensiblebit/certkit/commit/84c4edf [`2b8cb8c`]: https://github.com/sensiblebit/certkit/commit/2b8cb8c From 4f6884e8145d8687f050bd79db67f56aeef22490 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 06:03:21 -0500 Subject: [PATCH 13/30] fix: include QUIC ciphers in overall rating and diagnostics, fix spinner data race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Fix OverallRating, FormatCipherRatingLine, and DiagnoseCipherScan ignoring QUIC ciphers — weak QUIC suites were excluded from the overall rating computation and diagnostic count - Fix data race on spinner.started — replace bool with atomic.Bool for safe concurrent access between Start() and Stop() goroutines - Fix bare error returns in deriveTrafficKeys — wrap with context - Replace commit SHA changelog refs with PR refs for squash merge - Add QUIC weak cipher test cases, unknown cipher ID coverage - Remove redundant test cases per T-14 Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 16 ++++++++++----- cmd/certkit/spinner.go | 7 ++++--- connect.go | 23 +++++++++++++++++++--- connect_test.go | 44 ++++++++++++++++++++++++++---------------- quicprobe.go | 6 +++--- 5 files changed, 65 insertions(+), 31 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index a1f873c..62f0fc4 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,8 +76,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([`7a155c3`]) -- Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([`7a155c3`]) +- Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([#82]) +- Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([#82]) +- Fix `OverallRating`, `FormatCipherRatingLine`, and `DiagnoseCipherScan` ignoring QUIC ciphers — weak QUIC ciphers were excluded from the overall rating and diagnostic count ([#82]) +- Fix data race on `spinner.started` — replace `bool` with `atomic.Bool` for safe concurrent access (CC-3) ([#82]) +- Fix bare error returns in `deriveTrafficKeys` — wrap with `%w` context per ERR-1 ([#82]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) @@ -162,11 +165,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix brittle `tls13Count != 3` assertion — use `>= 1` to tolerate future Go TLS 1.3 cipher additions ([#82]) - Consolidate `FormatCipherScanResult` tests — merge QUIC and key exchange standalone tests into table-driven test ([#82]) - Consolidate `BuildClientHello` tests — merge ALPN/QUIC test into subtests with session ID assertion ([#82]) -- Add nil and empty-ciphers test cases to `TestFormatCipherScanResult` — previously the empty case asserted nothing ([`7a155c3`]) -- Consolidate `startTLSServer` to delegate to `startTLSServerWithConfig` — eliminates duplicated accept-loop code ([`7a155c3`]) +- Add nil and empty-ciphers test cases to `TestFormatCipherScanResult` — previously the empty case asserted nothing ([#82]) +- Consolidate `startTLSServer` to delegate to `startTLSServerWithConfig` — eliminates duplicated accept-loop code ([#82]) - Remove tests that validate upstream behavior rather than certkit logic: `TestDeriveQUICInitialKeys`, `TestGenerateKeyShare`, `TestIsPQKeyExchange` ([#82]) - Add `parseServerHello` edge case tests — oversized session ID length, truncation at compression method ([#82]) - Add `FormatConnectResult` tests for "Verify: FAILED" and "Client Auth: any CA" paths ([#82]) +- Add QUIC weak cipher test case to `TestDiagnoseCipherScan` — validates QUIC ciphers are included in diagnostic count ([#82]) +- Add QUIC-only test case to `TestFormatCipherRatingLine` — validates QUIC ciphers counted in rating summary ([#82]) +- Replace RC4 test case with unknown cipher ID (0xFFFF) in `TestRateCipherSuite` — tests conservative rating for unrecognized ciphers ([#82]) +- Remove redundant `TestFormatCipherScanResult/single_cipher` and `TestFormatCipherRatingLine/TCP_good_QUIC_weak` — subsumed by stronger cases (T-14) ([#82]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) @@ -798,7 +805,6 @@ Initial release. [0.1.2]: https://github.com/sensiblebit/certkit/compare/v0.1.1...v0.1.2 [0.1.1]: https://github.com/sensiblebit/certkit/compare/v0.1.0...v0.1.1 [0.1.0]: https://github.com/sensiblebit/certkit/releases/tag/v0.1.0 -[`7a155c3`]: https://github.com/sensiblebit/certkit/commit/7a155c3 [`2693116`]: https://github.com/sensiblebit/certkit/commit/2693116 [`84c4edf`]: https://github.com/sensiblebit/certkit/commit/84c4edf [`2b8cb8c`]: https://github.com/sensiblebit/certkit/commit/2b8cb8c diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go index 827e0ea..bce3d8a 100644 --- a/cmd/certkit/spinner.go +++ b/cmd/certkit/spinner.go @@ -5,6 +5,7 @@ import ( "fmt" "os" "sync" + "sync/atomic" "time" "github.com/mattn/go-isatty" @@ -19,7 +20,7 @@ type spinner struct { done chan struct{} startOnce sync.Once stopOnce sync.Once - started bool + started atomic.Bool } // newSpinner creates a spinner with the given message. Call Start() to begin @@ -43,7 +44,7 @@ func (s *spinner) Start(ctx context.Context) { return } - s.started = true + s.started.Store(true) go s.run(ctx) }) } @@ -57,7 +58,7 @@ func (s *spinner) SetMessage(msg string) { // Stop halts the spinner and clears the line. Safe to call multiple times. func (s *spinner) Stop() { - if !s.started { + if !s.started.Load() { <-s.done return } diff --git a/connect.go b/connect.go index 52e5906..497c3e2 100644 --- a/connect.go +++ b/connect.go @@ -966,10 +966,10 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher return cmp.Compare(b.ID, a.ID) }) - // Compute supported versions and overall rating. + // Compute supported versions and overall rating across both TCP and QUIC ciphers. versionSet := make(map[string]bool) var overall CipherRating - if len(results) > 0 { + if len(results) > 0 || len(quicCiphers) > 0 { overall = CipherRatingGood for _, r := range results { versionSet[r.Version] = true @@ -977,6 +977,11 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher overall = r.Rating } } + for _, r := range quicCiphers { + if ratingRank(r.Rating) > ratingRank(overall) { + overall = r.Rating + } + } } var versions []string @@ -1135,6 +1140,11 @@ func DiagnoseCipherScan(r *CipherScanResult) []ChainDiagnostic { weak++ } } + for _, c := range r.QUICCiphers { + if c.Rating == CipherRatingWeak { + weak++ + } + } if weak == 0 { return nil } @@ -1149,7 +1159,7 @@ func DiagnoseCipherScan(r *CipherScanResult) []ChainDiagnostic { // FormatCipherRatingLine formats a one-line summary for the connect header block, // positioned alongside Host/Protocol/OCSP etc. func FormatCipherRatingLine(r *CipherScanResult) string { - if r == nil || len(r.Ciphers) == 0 { + if r == nil || (len(r.Ciphers) == 0 && len(r.QUICCiphers) == 0) { return "" } @@ -1161,6 +1171,13 @@ func FormatCipherRatingLine(r *CipherScanResult) string { weak++ } } + for _, c := range r.QUICCiphers { + if c.Rating == CipherRatingGood { + strong++ + } else { + weak++ + } + } return fmt.Sprintf("Ciphers: %s (%d good, %d weak)\n", r.OverallRating, strong, weak) } diff --git a/connect_test.go b/connect_test.go index 7b11446..99d5cdc 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1241,9 +1241,10 @@ func TestRateCipherSuite(t *testing.T) { want: CipherRatingWeak, }, // InsecureCipherSuites list — weak (RC4). + // Unknown cipher IDs should be rated conservatively. { - name: "TLS 1.2 insecure list RC4 weak", - cipherID: tls.TLS_RSA_WITH_RC4_128_SHA, + name: "unknown cipher ID weak", + cipherID: 0xFFFF, tlsVersion: tls.VersionTLS12, want: CipherRatingWeak, }, @@ -1415,21 +1416,6 @@ func TestFormatCipherScanResult(t *testing.T) { "TLS_RSA_WITH_AES_128_CBC_SHA", }, }, - { - name: "single cipher", - result: &CipherScanResult{ - SupportedVersions: []string{"TLS 1.3"}, - Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, - }, - OverallRating: CipherRatingGood, - }, - wantStrings: []string{ - "Cipher suites (1 supported)", - "TLS 1.3 (ECDHE):", - "[good]", - }, - }, { name: "QUIC and key exchanges", result: &CipherScanResult{ @@ -1529,6 +1515,17 @@ func TestFormatCipherRatingLine(t *testing.T) { }, want: "Ciphers: weak (1 good, 1 weak)\n", }, + { + name: "QUIC only", + scan: &CipherScanResult{ + QUICCiphers: []CipherProbeResult{ + {Rating: CipherRatingGood}, + {Rating: CipherRatingWeak}, + }, + OverallRating: CipherRatingWeak, + }, + want: "Ciphers: weak (1 good, 1 weak)\n", + }, } for _, tt := range tests { @@ -1577,6 +1574,19 @@ func TestDiagnoseCipherScan(t *testing.T) { wantChecks: 1, wantDetail: "server accepts 2 weak cipher suite(s) that should be disabled", }, + { + name: "QUIC weak ciphers counted", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, + }, + QUICCiphers: []CipherProbeResult{ + {Name: "TLS_AES_128_CCM_8_SHA256", Rating: CipherRatingWeak}, + }, + }, + wantChecks: 1, + wantDetail: "server accepts 1 weak cipher suite(s) that should be disabled", + }, } for _, tt := range tests { diff --git a/quicprobe.go b/quicprobe.go index ea3ac14..cbb9e05 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -71,15 +71,15 @@ func deriveQUICInitialKeys(dcid []byte) (client, server quicInitialKeys, err err func deriveTrafficKeys(secret []byte) (quicInitialKeys, error) { key, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic key", length: 16}) if err != nil { - return quicInitialKeys{}, err + return quicInitialKeys{}, fmt.Errorf("expanding quic key: %w", err) } iv, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic iv", length: 12}) if err != nil { - return quicInitialKeys{}, err + return quicInitialKeys{}, fmt.Errorf("expanding quic iv: %w", err) } hp, err := hkdfExpandLabel(hkdfExpandLabelInput{secret: secret, label: "quic hp", length: 16}) if err != nil { - return quicInitialKeys{}, err + return quicInitialKeys{}, fmt.Errorf("expanding quic hp: %w", err) } return quicInitialKeys{key: key, iv: iv, hp: hp}, nil } From 8ee4402d5ed5de4187588082e06bf473cddf21a0 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 07:18:42 -0500 Subject: [PATCH 14/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20error=20wrapping,=20QUIC=20bounds=20checks,=20test?= =?UTF-8?q?=20hardening?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Wrap ConnectTLS and ScanCipherSuites errors with host context (ERR-1) - Add bounds check before QUIC packet number unmasking (OOB write) - Add panic guard to appendQUICVarint2 for overflow values - Skip QUIC probes on non-443 ports to avoid wasted timeouts - Add context cancellation test for ScanCipherSuites - Add InsecureCipherSuites isolation test (ECDHE+RC4) - Remove redundant per-cipher rating loop (covered by TestRateCipherSuite) - Strengthen TestDiagnoseCipherScan with exact match assertions - Add empty-non-nil edge case to TestFormatCipherRatingLine Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 4 ++++ cmd/certkit/connect.go | 4 ++-- connect.go | 5 +++-- connect_test.go | 41 ++++++++++++++++++++++++++++------------- quicprobe.go | 9 +++++++++ 5 files changed, 46 insertions(+), 17 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 62f0fc4..7694f27 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -76,6 +76,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed +- Fix bare `return err` in `connect` CLI dropping host context from error messages — ConnectTLS and ScanCipherSuites errors now wrap with host and operation (ERR-1) ([#82]) +- Fix potential out-of-bounds write in QUIC response parser when packet number length exceeds remaining packet bytes ([#82]) +- Add panic guard to `appendQUICVarint2` for values >= 16384 that would silently produce corrupt 2-byte encoding ([#82]) +- Skip QUIC cipher probes on non-443 ports — avoids wasted 10s of timeout when QUIC is not conventionally served ([#82]) - Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([#82]) - Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([#82]) - Fix `OverallRating`, `FormatCipherRatingLine`, and `DiagnoseCipherScan` ignoring QUIC ciphers — weak QUIC ciphers were excluded from the overall rating and diagnostic count ([#82]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index b9487db..e4faad9 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -120,7 +120,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if err != nil { spin.Stop() - return err + return fmt.Errorf("connecting to %s: %w", args[0], err) } // Optional cipher suite enumeration. @@ -137,7 +137,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if scanErr != nil { spin.Stop() - return scanErr + return fmt.Errorf("scanning cipher suites for %s: %w", args[0], scanErr) } result.CipherScan = cipherScan result.Diagnostics = append(result.Diagnostics, certkit.DiagnoseCipherScan(cipherScan)...) diff --git a/connect.go b/connect.go index 497c3e2..b9123a7 100644 --- a/connect.go +++ b/connect.go @@ -900,8 +900,9 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher } // Probe QUIC/UDP cipher suites if requested. + // Skip non-443 ports since QUIC is only conventionally served on 443. var quicCiphers []CipherProbeResult - if input.ProbeQUIC { + if input.ProbeQUIC && port == "443" { quicAddr := net.JoinHostPort(input.Host, port) for _, id := range tls13CipherSuites { if ctx.Err() != nil { @@ -1008,7 +1009,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher return &CipherScanResult{ SupportedVersions: versions, Ciphers: results, - QUICProbed: input.ProbeQUIC, + QUICProbed: input.ProbeQUIC && port == "443", QUICCiphers: quicCiphers, KeyExchanges: keyExchanges, OverallRating: overall, diff --git a/connect_test.go b/connect_test.go index 99d5cdc..c06d600 100644 --- a/connect_test.go +++ b/connect_test.go @@ -1240,8 +1240,14 @@ func TestRateCipherSuite(t *testing.T) { tlsVersion: tls.VersionTLS12, want: CipherRatingWeak, }, - // InsecureCipherSuites list — weak (RC4). - // Unknown cipher IDs should be rated conservatively. + // InsecureCipherSuites list — ECDHE+RC4 is still weak despite forward secrecy. + { + name: "TLS 1.2 ECDHE+RC4 insecure", + cipherID: tls.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, + tlsVersion: tls.VersionTLS12, + want: CipherRatingWeak, + }, + // Unknown cipher IDs should be rated conservatively (non-ECDHE fallthrough). { name: "unknown cipher ID weak", cipherID: 0xFFFF, @@ -1328,14 +1334,8 @@ func TestScanCipherSuites(t *testing.T) { } } - // All detected ciphers should be rated excellent (GCM + ECDHE only). - for _, c := range result.Ciphers { - if c.Rating != CipherRatingGood { - t.Errorf("cipher %q (%s) rated %q, want %q", c.Name, c.Version, c.Rating, CipherRatingGood) - } - } - - // Overall rating should be excellent. + // Overall rating should be good (all configured ciphers are ECDHE+GCM). + // Per-cipher rating correctness is covered by TestRateCipherSuite. if result.OverallRating != CipherRatingGood { t.Errorf("OverallRating = %q, want %q", result.OverallRating, CipherRatingGood) } @@ -1373,6 +1373,16 @@ func TestScanCipherSuites_EmptyHost(t *testing.T) { } } +func TestScanCipherSuites_CancelledContext(t *testing.T) { + t.Parallel() + ctx, cancel := context.WithCancel(context.Background()) + cancel() + _, err := ScanCipherSuites(ctx, ScanCipherSuitesInput{Host: "127.0.0.1", Port: "443"}) + if err == nil { + t.Fatal("expected error for cancelled context") + } +} + func TestFormatCipherScanResult(t *testing.T) { t.Parallel() @@ -1493,6 +1503,11 @@ func TestFormatCipherRatingLine(t *testing.T) { scan: nil, want: "", }, + { + name: "empty scan", + scan: &CipherScanResult{}, + want: "", + }, { name: "all good", scan: &CipherScanResult{ @@ -1546,7 +1561,7 @@ func TestDiagnoseCipherScan(t *testing.T) { name string result *CipherScanResult wantChecks int - wantDetail string // substring in first diagnostic detail + wantDetail string // exact first diagnostic detail }{ { name: "nil result", @@ -1600,8 +1615,8 @@ func TestDiagnoseCipherScan(t *testing.T) { if diags[0].Check != "weak-cipher" { t.Errorf("Check = %q, want %q", diags[0].Check, "weak-cipher") } - if !strings.Contains(diags[0].Detail, tt.wantDetail) { - t.Errorf("Detail = %q, want substring %q", diags[0].Detail, tt.wantDetail) + if diags[0].Detail != tt.wantDetail { + t.Errorf("Detail = %q, want %q", diags[0].Detail, tt.wantDetail) } } }) diff --git a/quicprobe.go b/quicprobe.go index cbb9e05..c22c74c 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -311,6 +311,11 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve packet[0] ^= mask[0] & 0x0f pnLen := int(packet[0]&0x03) + 1 + // Validate that the packet number bytes fit within the packet. + if pnOffset+pnLen > len(packet) { + return nil, fmt.Errorf("packet truncated at packet number bytes") + } + // Unmask packet number. for i := range pnLen { packet[pnOffset+i] ^= mask[1+i] @@ -557,7 +562,11 @@ func appendQUICVarint(b []byte, v uint64) []byte { } // appendQUICVarint2 appends a 2-byte QUIC varint (for values < 16384). +// Panics if v >= 16384 since that requires a 4-byte encoding. func appendQUICVarint2(b []byte, v uint64) []byte { + if v >= 16384 { + panic(fmt.Sprintf("appendQUICVarint2: value %d exceeds 2-byte varint capacity (max 16383)", v)) + } return append(b, byte(0x40|v>>8), byte(v)) } From 604a45ac15098eaf2d61a4f8a13fe1d6c3991f98 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 08:47:32 -0500 Subject: [PATCH 15/30] =?UTF-8?q?feat:=20improve=20connect=20diagnostics?= =?UTF-8?q?=20=E2=80=94=20hostname=20mismatch,=20error-level=20diagnostics?= =?UTF-8?q?,=20specific=20cipher=20checks?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Verification failures (verify-failed, hostname-mismatch, ocsp-revoked, crl-revoked) now surface as [ERR] diagnostics in the output instead of a redundant Error: line on stderr. Exit code 2 is preserved. Cipher diagnostics replaced the single vague "N weak cipher suite(s)" message with specific actionable checks: deprecated-tls10, deprecated-tls11, cbc-cipher, static-rsa-kex, 3des-cipher. QUIC probing is no longer restricted to port 443. Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 5 ++ cmd/certkit/connect.go | 54 ++++++++++--- cmd/certkit/errors.go | 4 + cmd/certkit/main.go | 8 +- connect.go | 122 +++++++++++++++++++++++----- connect_test.go | 179 +++++++++++++++++++++++++++++++++++------ 6 files changed, 314 insertions(+), 58 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 7694f27..1a85a9d 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,6 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added +- Add hostname-mismatch diagnostic to `connect` — detects `x509.HostnameError` and surfaces it as `[ERR] hostname-mismatch` in the diagnostics section ([`pending`]) +- Add error-level diagnostics (`verify-failed`, `ocsp-revoked`, `crl-revoked`) to `connect` output — validation failures now appear in the Diagnostics section instead of a redundant `Error:` line on stderr ([`pending`]) +- Add specific cipher diagnostics to `connect --ciphers` — replaces the single "weak cipher" message with actionable checks: `deprecated-tls10`, `deprecated-tls11`, `cbc-cipher`, `static-rsa-kex`, `3des-cipher` ([`pending`]) - Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([#82]) - Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([#82]) - Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([#82]) @@ -57,6 +60,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed +- `connect` QUIC probing no longer restricted to port 443 — QUIC can run on any UDP port ([`pending`]) +- `connect` diagnostics now distinguish `[ERR]` (verification failures) from `[WARN]` (configuration issues) ([`pending`]) - Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([#82]) - Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) - Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([#82]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index e4faad9..f8131b4 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -147,6 +147,44 @@ func runConnect(cmd *cobra.Command, args []string) error { now := time.Now() + // Promote validation failures to error-level diagnostics so they appear + // in the Diagnostics section rather than as a separate Error: line. + var hasValidationError bool + if result.VerifyError != "" { + // Skip if hostname-mismatch diagnostic was already added by the library. + hasHostnameDiag := false + for _, d := range result.Diagnostics { + if d.Check == "hostname-mismatch" { + hasHostnameDiag = true + break + } + } + if !hasHostnameDiag { + result.Diagnostics = append(result.Diagnostics, certkit.ChainDiagnostic{ + Check: "verify-failed", + Status: "error", + Detail: result.VerifyError, + }) + } + hasValidationError = true + } + if result.OCSP != nil && result.OCSP.Status == "revoked" { + result.Diagnostics = append(result.Diagnostics, certkit.ChainDiagnostic{ + Check: "ocsp-revoked", + Status: "error", + Detail: "certificate is revoked (OCSP)", + }) + hasValidationError = true + } + if result.CRL != nil && result.CRL.Status == "revoked" { + result.Diagnostics = append(result.Diagnostics, certkit.ChainDiagnostic{ + Check: "crl-revoked", + Status: "error", + Detail: "certificate is revoked (CRL)", + }) + hasValidationError = true + } + format := connectFormat if jsonOutput { format = "json" @@ -214,14 +252,8 @@ func runConnect(cmd *cobra.Command, args []string) error { return fmt.Errorf("unsupported output format %q (use text or json)", format) } - if result.VerifyError != "" { - return &ValidationError{Message: fmt.Sprintf("certificate verification failed: %s", result.VerifyError)} - } - if result.OCSP != nil && result.OCSP.Status == "revoked" { - return &ValidationError{Message: "certificate is revoked (OCSP)"} - } - if result.CRL != nil && result.CRL.Status == "revoked" { - return &ValidationError{Message: "certificate is revoked (CRL)"} + if hasValidationError { + return &ValidationError{Message: "validation failed", Quiet: true} } return nil @@ -273,7 +305,11 @@ func formatConnectVerbose(r *certkit.ConnectResult, now time.Time) string { if len(r.Diagnostics) > 0 { out.WriteString("\nDiagnostics:\n") for _, d := range r.Diagnostics { - fmt.Fprintf(&out, " [WARN] %s: %s\n", d.Check, d.Detail) + tag := "WARN" + if d.Status == "error" { + tag = "ERR" + } + fmt.Fprintf(&out, " [%s] %s: %s\n", tag, d.Check, d.Detail) } } diff --git a/cmd/certkit/errors.go b/cmd/certkit/errors.go index 252764b..594abad 100644 --- a/cmd/certkit/errors.go +++ b/cmd/certkit/errors.go @@ -4,6 +4,10 @@ package main // key mismatch, expired). Commands return this to signal exit code 2. type ValidationError struct { Message string + // Quiet suppresses the "Error: ..." line on stderr. When true, the command + // has already displayed the failure details in its own output (e.g. as a + // diagnostic). The exit code is still 2. + Quiet bool } func (e *ValidationError) Error() string { return e.Message } diff --git a/cmd/certkit/main.go b/cmd/certkit/main.go index 86eb054..28f7778 100644 --- a/cmd/certkit/main.go +++ b/cmd/certkit/main.go @@ -20,11 +20,13 @@ func init() { func main() { rootCmd.Version = version if err := rootCmd.Execute(); err != nil { - fmt.Fprintf(os.Stderr, "Error: %s\n", err) - var ve *ValidationError - if errors.As(err, &ve) { + if ve, ok := errors.AsType[*ValidationError](err); ok { + if !ve.Quiet { + fmt.Fprintf(os.Stderr, "Error: %s\n", err) + } os.Exit(2) } + fmt.Fprintf(os.Stderr, "Error: %s\n", err) os.Exit(1) } } diff --git a/connect.go b/connect.go index b9123a7..f80c871 100644 --- a/connect.go +++ b/connect.go @@ -7,6 +7,7 @@ import ( "crypto/x509" "crypto/x509/pkix" "encoding/asn1" + "errors" "fmt" "log/slog" "net" @@ -20,7 +21,7 @@ import ( type ChainDiagnostic struct { // Check is the diagnostic identifier (e.g. "root-in-chain", "duplicate-cert", "missing-intermediate"). Check string `json:"check"` - // Status is the severity level (currently always "warn"). + // Status is the severity level: "warn" for configuration issues, "error" for verification failures. Status string `json:"status"` // Detail is a human-readable description of the issue. Detail string `json:"detail"` @@ -67,6 +68,22 @@ func DiagnoseConnectChain(input DiagnoseConnectChainInput) []ChainDiagnostic { return diags } +// DiagnoseVerifyError returns diagnostics derived from a chain verification error. +// Currently detects hostname mismatches (x509.HostnameError). +func DiagnoseVerifyError(verifyErr error) []ChainDiagnostic { + if verifyErr == nil { + return nil + } + if hostErr, ok := errors.AsType[x509.HostnameError](verifyErr); ok { + return []ChainDiagnostic{{ + Check: "hostname-mismatch", + Status: "error", + Detail: hostErr.Error(), + }} + } + return nil +} + // ConnectTLSInput contains parameters for a TLS connection probe. type ConnectTLSInput struct { // Host is the hostname or IP to connect to. @@ -283,6 +300,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err } if verifyErr != nil { result.VerifyError = verifyErr.Error() + result.Diagnostics = append(result.Diagnostics, DiagnoseVerifyError(verifyErr)...) } else { result.VerifiedChains = chains } @@ -900,9 +918,8 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher } // Probe QUIC/UDP cipher suites if requested. - // Skip non-443 ports since QUIC is only conventionally served on 443. var quicCiphers []CipherProbeResult - if input.ProbeQUIC && port == "443" { + if input.ProbeQUIC { quicAddr := net.JoinHostPort(input.Host, port) for _, id := range tls13CipherSuites { if ctx.Err() != nil { @@ -1009,7 +1026,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher return &CipherScanResult{ SupportedVersions: versions, Ciphers: results, - QUICProbed: input.ProbeQUIC && port == "443", + QUICProbed: input.ProbeQUIC, QUICCiphers: quicCiphers, KeyExchanges: keyExchanges, OverallRating: overall, @@ -1128,33 +1145,92 @@ func ratingRank(r CipherRating) int { } } -// DiagnoseCipherScan inspects cipher scan results and returns diagnostics -// for weak cipher suites that should be disabled. +// DiagnoseCipherScan inspects cipher scan results and returns specific, +// actionable diagnostics for deprecated protocols, weak cipher modes, +// and insecure key exchange. func DiagnoseCipherScan(r *CipherScanResult) []ChainDiagnostic { if r == nil { return nil } - var weak int - for _, c := range r.Ciphers { - if c.Rating == CipherRatingWeak { - weak++ + allCiphers := slices.Concat(r.Ciphers, r.QUICCiphers) + if len(allCiphers) == 0 { + return nil + } + + var diags []ChainDiagnostic + + // Deprecated TLS versions (RFC 8996). + var tls10, tls11 int + for _, c := range allCiphers { + switch c.Version { + case "TLS 1.0": + tls10++ + case "TLS 1.1": + tls11++ } } - for _, c := range r.QUICCiphers { - if c.Rating == CipherRatingWeak { - weak++ + if tls10 > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "deprecated-tls10", + Status: "warn", + Detail: fmt.Sprintf("server supports TLS 1.0 (%d cipher suite(s)) — deprecated since RFC 8996", tls10), + }) + } + if tls11 > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "deprecated-tls11", + Status: "warn", + Detail: fmt.Sprintf("server supports TLS 1.1 (%d cipher suite(s)) — deprecated since RFC 8996", tls11), + }) + } + + // CBC mode cipher suites — vulnerable to padding oracle attacks (BEAST, Lucky13). + var cbc int + for _, c := range allCiphers { + if strings.Contains(c.Name, "CBC") { + cbc++ } } - if weak == 0 { - return nil + if cbc > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "cbc-cipher", + Status: "warn", + Detail: fmt.Sprintf("server accepts %d CBC mode cipher suite(s) — vulnerable to padding oracle attacks", cbc), + }) + } + + // Static RSA key exchange — no forward secrecy. + var staticRSA int + for _, c := range allCiphers { + if c.KeyExchange == "RSA" { + staticRSA++ + } + } + if staticRSA > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "static-rsa-kex", + Status: "warn", + Detail: fmt.Sprintf("server accepts %d static RSA key exchange cipher suite(s) — no forward secrecy", staticRSA), + }) + } + + // 3DES cipher suites — 64-bit block size, vulnerable to Sweet32. + var tripleDES int + for _, c := range allCiphers { + if strings.Contains(c.Name, "3DES") { + tripleDES++ + } + } + if tripleDES > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "3des-cipher", + Status: "warn", + Detail: fmt.Sprintf("server accepts %d 3DES cipher suite(s) — 64-bit block size, vulnerable to Sweet32", tripleDES), + }) } - return []ChainDiagnostic{{ - Check: "weak-cipher", - Status: "warn", - Detail: fmt.Sprintf("server accepts %d weak cipher suite(s) that should be disabled", weak), - }} + return diags } // FormatCipherRatingLine formats a one-line summary for the connect header block, @@ -1287,7 +1363,11 @@ func FormatConnectResult(r *ConnectResult) string { if len(r.Diagnostics) > 0 { out.WriteString("\nDiagnostics:\n") for _, d := range r.Diagnostics { - fmt.Fprintf(&out, " [WARN] %s: %s\n", d.Check, d.Detail) + tag := "WARN" + if d.Status == "error" { + tag = "ERR" + } + fmt.Fprintf(&out, " [%s] %s: %s\n", tag, d.Check, d.Detail) } } diff --git a/connect_test.go b/connect_test.go index c06d600..e7b2a85 100644 --- a/connect_test.go +++ b/connect_test.go @@ -8,6 +8,7 @@ import ( "crypto/tls" "crypto/x509" "crypto/x509/pkix" + "errors" "math/big" "net" "net/http" @@ -316,6 +317,18 @@ func TestFormatConnectResult(t *testing.T) { }, wantStrings: []string{"Diagnostics:", "[WARN] root-in-chain:", "Verify: OK\n"}, }, + { + name: "error-level diagnostic rendered with ERR tag", + diagnostics: []ChainDiagnostic{ + {Check: "hostname-mismatch", Status: "error", Detail: `x509: certificate is valid for *.badssl.com, badssl.com, not wrong.host.badssl.com`}, + }, + verifyError: "x509: certificate is valid for *.badssl.com, badssl.com, not wrong.host.badssl.com", + wantStrings: []string{ + "[ERR] hostname-mismatch:", + "Verify: FAILED", + }, + notWantStrings: []string{"[WARN] hostname-mismatch:"}, + }, { name: "AIA-aware verify line", aiaFetched: true, @@ -512,6 +525,85 @@ func TestDiagnoseConnectChain(t *testing.T) { } } +func TestDiagnoseVerifyError(t *testing.T) { + t.Parallel() + + // Generate a self-signed CA cert for "localhost" and trust it, so that + // verifying with a wrong DNSName triggers HostnameError (not UnknownAuthorityError). + key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) + if err != nil { + t.Fatal(err) + } + template := &x509.Certificate{ + SerialNumber: big.NewInt(1), + Subject: pkix.Name{CommonName: "localhost"}, + DNSNames: []string{"localhost"}, + NotBefore: time.Now().Add(-time.Hour), + NotAfter: time.Now().Add(24 * time.Hour), + IsCA: true, + BasicConstraintsValid: true, + } + certDER, err := x509.CreateCertificate(rand.Reader, template, template, &key.PublicKey, key) + if err != nil { + t.Fatal(err) + } + cert, err := x509.ParseCertificate(certDER) + if err != nil { + t.Fatal(err) + } + + roots := x509.NewCertPool() + roots.AddCert(cert) + + // Trigger a real HostnameError by verifying with wrong DNSName. + _, hostnameErr := cert.Verify(x509.VerifyOptions{DNSName: "wrong.example.com", Roots: roots}) + if hostnameErr == nil { + t.Fatal("expected verification error for wrong hostname") + } + + tests := []struct { + name string + err error + wantChecks []string + }{ + { + name: "hostname mismatch", + err: hostnameErr, + // The error chain may include both HostnameError and UnknownAuthorityError. + // We only care that hostname-mismatch is present. + wantChecks: []string{"hostname-mismatch"}, + }, + { + name: "non-hostname error", + err: errors.New("x509: certificate signed by unknown authority"), + wantChecks: nil, + }, + { + name: "nil error", + err: nil, + wantChecks: nil, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + diags := DiagnoseVerifyError(tt.err) + if len(diags) != len(tt.wantChecks) { + t.Fatalf("got %d diagnostics, want %d: %+v", len(diags), len(tt.wantChecks), diags) + } + for i, wantCheck := range tt.wantChecks { + if diags[i].Check != wantCheck { + t.Errorf("diag[%d].Check = %q, want %q", i, diags[i].Check, wantCheck) + } + if diags[i].Status != "error" { + t.Errorf("diag[%d].Status = %q, want %q", i, diags[i].Status, "error") + } + } + }) + } +} + func TestConnectTLS_AIAFetch(t *testing.T) { t.Parallel() @@ -1560,47 +1652,77 @@ func TestDiagnoseCipherScan(t *testing.T) { tests := []struct { name string result *CipherScanResult - wantChecks int - wantDetail string // exact first diagnostic detail + wantChecks []string // expected diagnostic check names in order + wantSubs [][]string // per-diagnostic substrings to match in Detail }{ { - name: "nil result", - result: nil, - wantChecks: 0, + name: "nil result", + result: nil, }, { name: "all good — no diagnostics", result: &CipherScanResult{ Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", Version: "TLS 1.2", KeyExchange: "ECDHE", Rating: CipherRatingGood}, }, }, - wantChecks: 0, }, { - name: "weak ciphers present", + name: "deprecated TLS 1.0 with CBC and static RSA and 3DES", result: &CipherScanResult{ Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, - {Name: "TLS_RSA_WITH_AES_128_CBC_SHA", Version: "TLS 1.2", Rating: CipherRatingWeak}, - {Name: "TLS_RSA_WITH_3DES_EDE_CBC_SHA", Version: "TLS 1.0", Rating: CipherRatingWeak}, + {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", KeyExchange: "ECDHE", Rating: CipherRatingGood}, + {Name: "TLS_RSA_WITH_AES_128_CBC_SHA", Version: "TLS 1.0", KeyExchange: "RSA", Rating: CipherRatingWeak}, + {Name: "TLS_RSA_WITH_3DES_EDE_CBC_SHA", Version: "TLS 1.0", KeyExchange: "RSA", Rating: CipherRatingWeak}, }, }, - wantChecks: 1, - wantDetail: "server accepts 2 weak cipher suite(s) that should be disabled", + wantChecks: []string{"deprecated-tls10", "cbc-cipher", "static-rsa-kex", "3des-cipher"}, + wantSubs: [][]string{ + {"TLS 1.0", "2 cipher"}, + {"CBC", "2"}, + {"static RSA", "2"}, + {"3DES", "1"}, + }, }, { - name: "QUIC weak ciphers counted", + name: "deprecated TLS 1.1", result: &CipherScanResult{ Ciphers: []CipherProbeResult{ - {Name: "TLS_AES_128_GCM_SHA256", Version: "TLS 1.3", Rating: CipherRatingGood}, + {Name: "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", Version: "TLS 1.1", KeyExchange: "ECDHE", Rating: CipherRatingWeak}, }, + }, + wantChecks: []string{"deprecated-tls11", "cbc-cipher"}, + wantSubs: [][]string{{"TLS 1.1", "1"}, {"CBC", "1"}}, + }, + { + name: "CBC only at TLS 1.2", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", Version: "TLS 1.2", KeyExchange: "ECDHE", Rating: CipherRatingWeak}, + }, + }, + wantChecks: []string{"cbc-cipher"}, + wantSubs: [][]string{{"CBC", "1"}}, + }, + { + name: "static RSA with GCM at TLS 1.2", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_RSA_WITH_AES_128_GCM_SHA256", Version: "TLS 1.2", KeyExchange: "RSA", Rating: CipherRatingWeak}, + }, + }, + wantChecks: []string{"static-rsa-kex"}, + wantSubs: [][]string{{"static RSA", "1"}}, + }, + { + name: "QUIC ciphers included in analysis", + result: &CipherScanResult{ QUICCiphers: []CipherProbeResult{ - {Name: "TLS_AES_128_CCM_8_SHA256", Rating: CipherRatingWeak}, + {Name: "TLS_RSA_WITH_AES_128_CBC_SHA", Version: "TLS 1.0", KeyExchange: "RSA", Rating: CipherRatingWeak}, }, }, - wantChecks: 1, - wantDetail: "server accepts 1 weak cipher suite(s) that should be disabled", + wantChecks: []string{"deprecated-tls10", "cbc-cipher", "static-rsa-kex"}, }, } @@ -1608,15 +1730,22 @@ func TestDiagnoseCipherScan(t *testing.T) { t.Run(tt.name, func(t *testing.T) { t.Parallel() diags := DiagnoseCipherScan(tt.result) - if len(diags) != tt.wantChecks { - t.Fatalf("got %d diagnostics, want %d: %+v", len(diags), tt.wantChecks, diags) + if len(diags) != len(tt.wantChecks) { + t.Fatalf("got %d diagnostics, want %d: %+v", len(diags), len(tt.wantChecks), diags) } - if tt.wantChecks > 0 { - if diags[0].Check != "weak-cipher" { - t.Errorf("Check = %q, want %q", diags[0].Check, "weak-cipher") + for i, wantCheck := range tt.wantChecks { + if diags[i].Check != wantCheck { + t.Errorf("diag[%d].Check = %q, want %q", i, diags[i].Check, wantCheck) } - if diags[0].Detail != tt.wantDetail { - t.Errorf("Detail = %q, want %q", diags[0].Detail, tt.wantDetail) + if diags[i].Status != "warn" { + t.Errorf("diag[%d].Status = %q, want %q", i, diags[i].Status, "warn") + } + if i < len(tt.wantSubs) { + for _, sub := range tt.wantSubs[i] { + if !strings.Contains(diags[i].Detail, sub) { + t.Errorf("diag[%d].Detail missing %q, got: %s", i, sub, diags[i].Detail) + } + } } } }) From 8064e813e98e2514cdce8ed8e8a296c8f7d67a9b Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 08:50:21 -0500 Subject: [PATCH 16/30] =?UTF-8?q?fix:=20sort=20diagnostics=20=E2=80=94=20e?= =?UTF-8?q?rrors=20first,=20then=20alphabetically=20by=20check=20name?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Ensures stable output order regardless of the order diagnostics are appended from different sources (chain analysis, verify errors, cipher scan). Co-Authored-By: Claude Opus 4.6 --- cmd/certkit/connect.go | 2 ++ connect.go | 17 +++++++++++++++++ connect_test.go | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 52 insertions(+) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index f8131b4..b169438 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -185,6 +185,8 @@ func runConnect(cmd *cobra.Command, args []string) error { hasValidationError = true } + certkit.SortDiagnostics(result.Diagnostics) + format := connectFormat if jsonOutput { format = "json" diff --git a/connect.go b/connect.go index f80c871..0864237 100644 --- a/connect.go +++ b/connect.go @@ -68,6 +68,23 @@ func DiagnoseConnectChain(input DiagnoseConnectChainInput) []ChainDiagnostic { return diags } +// SortDiagnostics sorts diagnostics: errors before warnings, then alphabetically +// by check name within each group for stable output order. +func SortDiagnostics(diags []ChainDiagnostic) { + slices.SortStableFunc(diags, func(a, b ChainDiagnostic) int { + // Errors first. + if a.Status != b.Status { + if a.Status == "error" { + return -1 + } + if b.Status == "error" { + return 1 + } + } + return cmp.Compare(a.Check, b.Check) + }) +} + // DiagnoseVerifyError returns diagnostics derived from a chain verification error. // Currently detects hostname mismatches (x509.HostnameError). func DiagnoseVerifyError(verifyErr error) []ChainDiagnostic { diff --git a/connect_test.go b/connect_test.go index e7b2a85..a7b413b 100644 --- a/connect_test.go +++ b/connect_test.go @@ -525,6 +525,39 @@ func TestDiagnoseConnectChain(t *testing.T) { } } +func TestSortDiagnostics(t *testing.T) { + t.Parallel() + + diags := []ChainDiagnostic{ + {Check: "deprecated-tls10", Status: "warn", Detail: "..."}, + {Check: "cbc-cipher", Status: "warn", Detail: "..."}, + {Check: "verify-failed", Status: "error", Detail: "..."}, + {Check: "3des-cipher", Status: "warn", Detail: "..."}, + {Check: "hostname-mismatch", Status: "error", Detail: "..."}, + {Check: "static-rsa-kex", Status: "warn", Detail: "..."}, + } + + SortDiagnostics(diags) + + wantOrder := []string{ + "hostname-mismatch", // error, alpha first + "verify-failed", // error, alpha second + "3des-cipher", // warn, alpha + "cbc-cipher", + "deprecated-tls10", + "static-rsa-kex", + } + + if len(diags) != len(wantOrder) { + t.Fatalf("got %d diagnostics, want %d", len(diags), len(wantOrder)) + } + for i, want := range wantOrder { + if diags[i].Check != want { + t.Errorf("diags[%d].Check = %q, want %q", i, diags[i].Check, want) + } + } +} + func TestDiagnoseVerifyError(t *testing.T) { t.Parallel() From 715cb8110063995bb17dbc19a4f20719572ddd93 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 13:14:51 -0500 Subject: [PATCH 17/30] =?UTF-8?q?feat:=20add=20raw=20TLS=201.0=E2=80=931.2?= =?UTF-8?q?=20legacy=20prober=20for=20DHE/static-RSA-only=20servers?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Go's crypto/tls has never implemented DHE key exchange and doesn't offer static RSA by default. Servers that only support these cipher suites (e.g. badssl.com DHE endpoints) fail with "handshake failure". This adds a byte-level TLS 1.0–1.2 ClientHello prober (extending the existing tls13probe.go approach) that can: 1. Probe 13 DHE/DHE-DSS cipher suites in `--ciphers` scans 2. Fall back to raw handshake in ConnectTLS when Go's handshake fails, extracting the server certificate chain for inspection 3. Diagnose the negotiated cipher suite on every connect (CBC, 3DES, static RSA, DHE, deprecated TLS versions) — no --ciphers needed New files: - legacyprobe.go: cipher registry, buildLegacyClientHelloMsg, probeLegacyCipher, readServerCertificates, parseCertificateMessage, legacyFallbackConnect - legacyprobe_test.go: unit tests for packet construction + parsing Modified: - connect.go: populateConnectResult helper (shared normal/legacy paths), legacy fallback in ConnectTLS, DHE probes in ScanCipherSuites, DiagnoseNegotiatedCipher, dhe-kex diagnostic, LegacyProbe field - connect_test.go: TestDiagnoseNegotiatedCipher, DHE cases in TestDiagnoseCipherScan - cmd/certkit/connect.go: LegacyProbe in JSON output Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 5 + cmd/certkit/connect.go | 2 + connect.go | 207 +++++++++++++++-- connect_test.go | 104 +++++++++ legacyprobe.go | 369 +++++++++++++++++++++++++++++++ legacyprobe_test.go | 491 +++++++++++++++++++++++++++++++++++++++++ 6 files changed, 1160 insertions(+), 18 deletions(-) create mode 100644 legacyprobe.go create mode 100644 legacyprobe_test.go diff --git a/CHANGELOG.md b/CHANGELOG.md index 1a85a9d..ac5cee5 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added +- Add raw TLS 1.0–1.2 legacy prober for DHE/DHE-DSS cipher suites that Go's `crypto/tls` doesn't implement — probes individual suites via byte-level ClientHello construction ([`pending`]) +- Add legacy fallback to `connect` — when Go's TLS handshake fails, attempts a raw handshake to extract server certificates from DHE-only or static-RSA-only servers ([`pending`]) +- Add DHE cipher suite probing to `connect --ciphers` — detects 13 DHE/DHE-DSS cipher suites using raw ClientHello packets, all rated "weak" ([`pending`]) +- Add `dhe-kex` diagnostic to `connect --ciphers` — warns when server accepts DHE key exchange cipher suites (deprecated, vulnerable to small DH parameters) ([`pending`]) +- Add negotiated cipher diagnostics to `connect` — warns about CBC mode, 3DES, static RSA, DHE, and deprecated TLS versions even without `--ciphers` ([`pending`]) - Add hostname-mismatch diagnostic to `connect` — detects `x509.HostnameError` and surfaces it as `[ERR] hostname-mismatch` in the diagnostics section ([`pending`]) - Add error-level diagnostics (`verify-failed`, `ocsp-revoked`, `crl-revoked`) to `connect` output — validation failures now appear in the Diagnostics section instead of a redundant `Error:` line on stderr ([`pending`]) - Add specific cipher diagnostics to `connect --ciphers` — replaces the single "weak cipher" message with actionable checks: `deprecated-tls10`, `deprecated-tls11`, `cbc-cipher`, `static-rsa-kex`, `3des-cipher` ([`pending`]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index b169438..94f7ba9 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -72,6 +72,7 @@ type connectResultJSON struct { OCSP *certkit.OCSPResult `json:"ocsp,omitempty"` CRL *certkit.CRLCheckResult `json:"crl,omitempty"` CipherScan *certkit.CipherScanResult `json:"cipher_scan,omitempty"` + LegacyProbe bool `json:"legacy_probe,omitempty"` Chain []connectCertJSON `json:"chain"` } @@ -208,6 +209,7 @@ func runConnect(cmd *cobra.Command, args []string) error { OCSP: result.OCSP, CRL: result.CRL, CipherScan: result.CipherScan, + LegacyProbe: result.LegacyProbe, } for _, cert := range result.PeerChain { cj := connectCertJSON{ diff --git a/connect.go b/connect.go index 0864237..dca24d3 100644 --- a/connect.go +++ b/connect.go @@ -101,6 +101,66 @@ func DiagnoseVerifyError(verifyErr error) []ChainDiagnostic { return nil } +// DiagnoseNegotiatedCipher returns diagnostics for the cipher suite and protocol +// version that were actually negotiated during the TLS handshake. This catches +// issues like CBC mode or deprecated TLS versions even without a full --ciphers scan. +func DiagnoseNegotiatedCipher(protocol, cipherSuite string) []ChainDiagnostic { + var diags []ChainDiagnostic + + // Deprecated TLS versions (RFC 8996). + switch protocol { + case "TLS 1.0": + diags = append(diags, ChainDiagnostic{ + Check: "deprecated-tls10", + Status: "warn", + Detail: "negotiated TLS 1.0 — deprecated since RFC 8996", + }) + case "TLS 1.1": + diags = append(diags, ChainDiagnostic{ + Check: "deprecated-tls11", + Status: "warn", + Detail: "negotiated TLS 1.1 — deprecated since RFC 8996", + }) + } + + // CBC mode — vulnerable to padding oracle attacks (BEAST, Lucky13). + if strings.Contains(cipherSuite, "CBC") { + diags = append(diags, ChainDiagnostic{ + Check: "cbc-cipher", + Status: "warn", + Detail: fmt.Sprintf("negotiated CBC mode cipher suite %s — vulnerable to padding oracle attacks", cipherSuite), + }) + } + + // 3DES — 64-bit block size, vulnerable to Sweet32. + if strings.Contains(cipherSuite, "3DES") { + diags = append(diags, ChainDiagnostic{ + Check: "3des-cipher", + Status: "warn", + Detail: fmt.Sprintf("negotiated 3DES cipher suite %s — 64-bit block size, vulnerable to Sweet32", cipherSuite), + }) + } + + // Key exchange issues. + kex := cipherKeyExchange(cipherSuite, protocol) + switch kex { + case "RSA": + diags = append(diags, ChainDiagnostic{ + Check: "static-rsa-kex", + Status: "warn", + Detail: fmt.Sprintf("negotiated static RSA key exchange (%s) — no forward secrecy", cipherSuite), + }) + case "DHE", "DHE-DSS": + diags = append(diags, ChainDiagnostic{ + Check: "dhe-kex", + Status: "warn", + Detail: fmt.Sprintf("negotiated DHE key exchange (%s) — deprecated, no guaranteed forward secrecy with small DH parameters", cipherSuite), + }) + } + + return diags +} + // ConnectTLSInput contains parameters for a TLS connection probe. type ConnectTLSInput struct { // Host is the hostname or IP to connect to. @@ -187,6 +247,11 @@ type ConnectResult struct { // CipherScan contains the cipher suite enumeration results. // Nil when cipher scanning is not requested. CipherScan *CipherScanResult `json:"cipher_scan,omitempty"` + // LegacyProbe is true when the certificate chain was obtained via a raw + // TLS handshake (legacy fallback) because Go's crypto/tls could not + // negotiate any cipher suite. The chain is still valid for inspection + // but no full TLS connection was established. + LegacyProbe bool `json:"legacy_probe,omitempty"` } // ConnectTLS connects to a TLS server and returns connection details including @@ -251,7 +316,31 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err handshakeErr := tlsConn.HandshakeContext(ctx) if handshakeErr != nil && clientAuth == nil { - return nil, fmt.Errorf("TLS handshake with %s: %w", addr, handshakeErr) + _ = tlsConn.Close() + // Try raw legacy handshake to detect DHE/static-RSA-only servers. + legacyResult, legacyErr := legacyFallbackConnect(ctx, legacyFallbackInput{ + addr: addr, + serverName: serverName, + }) + if legacyErr != nil { + return nil, fmt.Errorf("TLS handshake with %s: %w", addr, handshakeErr) + } + result := &ConnectResult{ + Host: input.Host, + Port: port, + Protocol: tlsVersionString(legacyResult.version), + CipherSuite: legacyCipherSuiteName(legacyResult.cipherSuite), + ServerName: serverName, + PeerChain: legacyResult.certificates, + LegacyProbe: true, + } + populateConnectResult(ctx, result, input) + result.Diagnostics = append(result.Diagnostics, ChainDiagnostic{ + Check: "legacy-only", + Status: "warn", + Detail: "server only supports cipher suites not available in standard TLS libraries — connected via raw handshake", + }) + return result, nil } // When the server requested a client cert and rejected our empty @@ -271,22 +360,35 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err PeerChain: state.PeerCertificates, } + populateConnectResult(ctx, result, input) + return result, nil +} + +// populateConnectResult runs chain diagnostics, verification, OCSP, and CRL +// checks on a ConnectResult. It is shared between the normal handshake path +// and the legacy fallback path. +func populateConnectResult(ctx context.Context, result *ConnectResult, input ConnectTLSInput) { + serverName := result.ServerName + + // Diagnose the negotiated cipher suite and protocol version. + result.Diagnostics = append(result.Diagnostics, DiagnoseNegotiatedCipher(result.Protocol, result.CipherSuite)...) + // Run chain diagnostics on the raw peer chain. - if len(state.PeerCertificates) > 0 { - result.Diagnostics = DiagnoseConnectChain(DiagnoseConnectChainInput{ - PeerChain: state.PeerCertificates, - }) + if len(result.PeerChain) > 0 { + result.Diagnostics = append(result.Diagnostics, DiagnoseConnectChain(DiagnoseConnectChainInput{ + PeerChain: result.PeerChain, + })...) } // Verify the chain ourselves to capture the error message. - if len(state.PeerCertificates) > 0 { - leaf := state.PeerCertificates[0] + if len(result.PeerChain) > 0 { + leaf := result.PeerChain[0] opts := x509.VerifyOptions{ DNSName: serverName, Intermediates: x509.NewCertPool(), Roots: input.RootCAs, } - for _, cert := range state.PeerCertificates[1:] { + for _, cert := range result.PeerChain[1:] { opts.Intermediates.AddCert(cert) } chains, verifyErr := leaf.Verify(opts) @@ -325,15 +427,15 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err // No peer certificates means TLS completed without sending certs (unlikely // but possible on a partially-completed handshake). Return early. - if len(state.PeerCertificates) == 0 { - return result, nil + if len(result.PeerChain) == 0 { + return } // Resolve the issuer certificate for revocation checks. // Only use VerifiedChains (cryptographically validated). Do not fall back // to PeerCertificates — those are raw, unverified certs from the server and // using them would let an attacker forge valid OCSP/CRL responses. - leaf := state.PeerCertificates[0] + leaf := result.PeerChain[0] var issuer *x509.Certificate if len(result.VerifiedChains) > 0 && len(result.VerifiedChains[0]) > 1 { issuer = result.VerifiedChains[0][1] @@ -388,8 +490,6 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err Detail: "no issuer certificate available to verify CRL signature", } } - - return result, nil } // CheckLeafCRLInput holds parameters for CheckLeafCRL. @@ -668,7 +768,8 @@ type ScanCipherSuitesInput struct { // cipherSuiteName returns a human-readable name for any TLS cipher suite. // It extends tls.CipherSuiteName with the two CCM suites from RFC 8446 that -// Go doesn't implement (0x1304, 0x1305) and would otherwise show as hex. +// Go doesn't implement (0x1304, 0x1305), legacy DHE/DHE-DSS suites, and would +// otherwise show as hex for unknown suites. func cipherSuiteName(id uint16) string { switch id { case 0x1304: @@ -676,6 +777,13 @@ func cipherSuiteName(id uint16) string { case 0x1305: return "TLS_AES_128_CCM_8_SHA256" default: + // Check legacy cipher registry before falling back to Go's function, + // which returns hex for unknown suites. + for _, def := range legacyCipherSuites { + if def.ID == id { + return def.Name + } + } return tls.CipherSuiteName(id) } } @@ -707,6 +815,9 @@ func cipherKeyExchange(name, version string) string { if strings.HasPrefix(name, "TLS_RSA_") { return "RSA" } + if strings.HasPrefix(name, "TLS_DHE_DSS_") { + return "DHE-DSS" + } if strings.HasPrefix(name, "TLS_DHE_") { return "DHE" } @@ -720,10 +831,12 @@ func kexRank(kex string) int { return 0 case "DHE": return 1 - case "RSA": + case "DHE-DSS": return 2 - default: + case "RSA": return 3 + default: + return 4 } } @@ -888,6 +1001,43 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher }(task) } + // Probe legacy cipher suites (DHE, DHE-DSS) using raw ClientHello packets. + // These suites are not implemented in Go's crypto/tls. + for _, def := range legacyCipherSuites { + if ctx.Err() != nil { + break + } + if !acquireSem() { + break + } + wg.Add(1) + go func(d legacyCipherDef) { + defer wg.Done() + defer func() { <-sem }() + + probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) + defer probeCancel() + + if probeLegacyCipher(probeCtx, cipherProbeInput{ + addr: addr, + serverName: serverName, + cipherID: d.ID, + version: tls.VersionTLS12, + }) { + r := CipherProbeResult{ + Name: d.Name, + ID: d.ID, + Version: "TLS 1.2", + KeyExchange: d.KeyExchange, + Rating: CipherRatingWeak, + } + mu.Lock() + results = append(results, r) + mu.Unlock() + } + }(def) + } + // Probe key exchange groups. TLS 1.3 groups use raw ClientHello packets; // classical groups also try TLS 1.2 (via crypto/tls CurvePreferences) // to cover servers that don't support TLS 1.3. @@ -1247,6 +1397,21 @@ func DiagnoseCipherScan(r *CipherScanResult) []ChainDiagnostic { }) } + // DHE key exchange — deprecated, vulnerable to small DH parameters. + var dhe int + for _, c := range allCiphers { + if c.KeyExchange == "DHE" || c.KeyExchange == "DHE-DSS" { + dhe++ + } + } + if dhe > 0 { + diags = append(diags, ChainDiagnostic{ + Check: "dhe-kex", + Status: "warn", + Detail: fmt.Sprintf("server accepts %d DHE key exchange cipher suite(s) — deprecated, no guaranteed forward secrecy with small DH parameters", dhe), + }) + } + return diags } @@ -1279,10 +1444,16 @@ func FormatCipherRatingLine(r *CipherScanResult) string { // kexLabel returns the display label for a key exchange type in the cipher // suite subgroup header, e.g. "ECDHE" or "RSA, no forward secrecy". func kexLabel(kex string) string { - if kex == "RSA" { + switch kex { + case "RSA": return "RSA, no forward secrecy" + case "DHE": + return "DHE, deprecated" + case "DHE-DSS": + return "DHE-DSS, deprecated" + default: + return kex } - return kex } // FormatCipherScanResult formats the cipher suite list as human-readable text. diff --git a/connect_test.go b/connect_test.go index a7b413b..e8588e2 100644 --- a/connect_test.go +++ b/connect_test.go @@ -637,6 +637,86 @@ func TestDiagnoseVerifyError(t *testing.T) { } } +func TestDiagnoseNegotiatedCipher(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + protocol string + cipherSuite string + wantChecks []string + wantSubs [][]string // per-diagnostic substrings to match in Detail + }{ + { + name: "TLS 1.3 with AEAD — no diagnostics", + protocol: "TLS 1.3", + cipherSuite: "TLS_AES_128_GCM_SHA256", + }, + { + name: "TLS 1.2 ECDHE GCM — no diagnostics", + protocol: "TLS 1.2", + cipherSuite: "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", + }, + { + name: "TLS 1.2 CBC cipher", + protocol: "TLS 1.2", + cipherSuite: "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", + wantChecks: []string{"cbc-cipher"}, + wantSubs: [][]string{{"CBC", "padding oracle"}}, + }, + { + name: "TLS 1.0 with CBC and static RSA", + protocol: "TLS 1.0", + cipherSuite: "TLS_RSA_WITH_AES_128_CBC_SHA", + wantChecks: []string{"deprecated-tls10", "cbc-cipher", "static-rsa-kex"}, + }, + { + name: "TLS 1.1 with 3DES", + protocol: "TLS 1.1", + cipherSuite: "TLS_RSA_WITH_3DES_EDE_CBC_SHA", + wantChecks: []string{"deprecated-tls11", "cbc-cipher", "3des-cipher", "static-rsa-kex"}, + }, + { + name: "DHE key exchange", + protocol: "TLS 1.2", + cipherSuite: "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256", + wantChecks: []string{"dhe-kex"}, + wantSubs: [][]string{{"DHE", "deprecated"}}, + }, + { + name: "DHE-DSS key exchange with CBC", + protocol: "TLS 1.2", + cipherSuite: "TLS_DHE_DSS_WITH_AES_128_CBC_SHA", + wantChecks: []string{"cbc-cipher", "dhe-kex"}, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + diags := DiagnoseNegotiatedCipher(tt.protocol, tt.cipherSuite) + if len(diags) != len(tt.wantChecks) { + t.Fatalf("got %d diagnostics, want %d: %+v", len(diags), len(tt.wantChecks), diags) + } + for i, wantCheck := range tt.wantChecks { + if diags[i].Check != wantCheck { + t.Errorf("diag[%d].Check = %q, want %q", i, diags[i].Check, wantCheck) + } + if diags[i].Status != "warn" { + t.Errorf("diag[%d].Status = %q, want %q", i, diags[i].Status, "warn") + } + if i < len(tt.wantSubs) { + for _, sub := range tt.wantSubs[i] { + if !strings.Contains(diags[i].Detail, sub) { + t.Errorf("diag[%d].Detail missing %q, got: %s", i, sub, diags[i].Detail) + } + } + } + } + }) + } +} + func TestConnectTLS_AIAFetch(t *testing.T) { t.Parallel() @@ -1757,6 +1837,30 @@ func TestDiagnoseCipherScan(t *testing.T) { }, wantChecks: []string{"deprecated-tls10", "cbc-cipher", "static-rsa-kex"}, }, + { + name: "DHE key exchange", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256", Version: "TLS 1.2", KeyExchange: "DHE", Rating: CipherRatingWeak}, + {Name: "TLS_DHE_DSS_WITH_AES_128_CBC_SHA", Version: "TLS 1.2", KeyExchange: "DHE-DSS", Rating: CipherRatingWeak}, + }, + }, + wantChecks: []string{"cbc-cipher", "dhe-kex"}, + wantSubs: [][]string{ + {"CBC", "1"}, + {"DHE", "2"}, + }, + }, + { + name: "DHE-RSA only — no CBC no static RSA", + result: &CipherScanResult{ + Ciphers: []CipherProbeResult{ + {Name: "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256", Version: "TLS 1.2", KeyExchange: "DHE", Rating: CipherRatingWeak}, + }, + }, + wantChecks: []string{"dhe-kex"}, + wantSubs: [][]string{{"DHE", "1", "deprecated"}}, + }, } for _, tt := range tests { diff --git a/legacyprobe.go b/legacyprobe.go new file mode 100644 index 0000000..964b2c3 --- /dev/null +++ b/legacyprobe.go @@ -0,0 +1,369 @@ +package certkit + +// This file implements a raw TLS 1.0–1.2 ClientHello prober for legacy cipher +// suites that Go's crypto/tls has never implemented (DHE key exchange, DHE-DSS). +// It extends the approach from tls13probe.go — byte-level packet construction, +// fully isolated probes, no shared state. +// +// The prober can: +// 1. Probe individual legacy cipher suites (probeLegacyCipher) +// 2. Perform a fallback connect that extracts server certificates +// (legacyFallbackConnect) when Go's TLS handshake fails + +import ( + "context" + "crypto/rand" + "crypto/tls" + "crypto/x509" + "encoding/binary" + "fmt" + "io" + "net" +) + +// legacyCipherDef describes a cipher suite not implemented by Go's crypto/tls. +type legacyCipherDef struct { + ID uint16 + Name string + KeyExchange string // "DHE", "DHE-DSS" +} + +// legacyCipherSuites lists DHE and DHE-DSS cipher suites missing from Go's +// crypto/tls. These require raw ClientHello probing. +var legacyCipherSuites = []legacyCipherDef{ + // DHE-RSA + {0x0033, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA", "DHE"}, + {0x0039, "TLS_DHE_RSA_WITH_AES_256_CBC_SHA", "DHE"}, + {0x0067, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA256", "DHE"}, + {0x006B, "TLS_DHE_RSA_WITH_AES_256_CBC_SHA256", "DHE"}, + {0x009E, "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256", "DHE"}, + {0x009F, "TLS_DHE_RSA_WITH_AES_256_GCM_SHA384", "DHE"}, + {0x0016, "TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA", "DHE"}, + // DHE-DSS + {0x0032, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA", "DHE-DSS"}, + {0x0038, "TLS_DHE_DSS_WITH_AES_256_CBC_SHA", "DHE-DSS"}, + {0x0040, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA256", "DHE-DSS"}, + {0x006A, "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256", "DHE-DSS"}, + {0x00A2, "TLS_DHE_DSS_WITH_AES_128_GCM_SHA256", "DHE-DSS"}, + {0x00A3, "TLS_DHE_DSS_WITH_AES_256_GCM_SHA384", "DHE-DSS"}, +} + +// legacyClientHelloInput contains parameters for building a raw TLS 1.0–1.2 ClientHello. +type legacyClientHelloInput struct { + serverName string + cipherSuites []uint16 +} + +// buildLegacyClientHelloMsg constructs a TLS 1.0–1.2 ClientHello handshake +// message offering the specified cipher suites. The legacy_version field is +// set to TLS 1.2 (0x0303); the server downgrades as needed. +// +// Unlike buildClientHelloMsg (TLS 1.3), this does NOT include +// supported_versions, key_share, or psk_key_exchange_modes extensions. +func buildLegacyClientHelloMsg(input legacyClientHelloInput) ([]byte, error) { + if len(input.cipherSuites) == 0 { + return nil, fmt.Errorf("building legacy ClientHello: no cipher suites specified") + } + + // Build extensions. + var exts []byte + exts = appendSNIExtension(exts, input.serverName) + exts = appendSignatureAlgorithmsExtension(exts) + exts = appendECPointFormatsExtension(exts) + + // Build ClientHello body. + var body []byte + + // Legacy version: TLS 1.2. + body = append(body, 0x03, 0x03) + + // Client random (32 bytes). + random := make([]byte, 32) + if _, err := io.ReadFull(rand.Reader, random); err != nil { + return nil, fmt.Errorf("generating client random: %w", err) + } + body = append(body, random...) + + // Session ID: empty (no middlebox compat needed for probing). + body = append(body, 0x00) + + // Cipher suites. + body = appendUint16(body, uint16(len(input.cipherSuites)*2)) + for _, cs := range input.cipherSuites { + body = appendUint16(body, cs) + } + + // Compression methods: null only. + body = append(body, 1, 0) + + // Extensions. + body = appendUint16(body, uint16(len(exts))) + body = append(body, exts...) + + // Wrap in handshake header: type(1) + length(3) + body. + msg := []byte{0x01} // ClientHello + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + + return msg, nil +} + +// appendECPointFormatsExtension appends an ec_point_formats extension (0x000b). +// Only uncompressed point format (0x00) is offered, which is required for +// interoperability and is the only format Go's crypto/tls supports. +func appendECPointFormatsExtension(b []byte) []byte { + b = appendUint16(b, 0x000b) // extension type + b = appendUint16(b, 2) // extension data length + b = append(b, 1) // formats list length + return append(b, 0x00) // uncompressed +} + +// probeLegacyCipher attempts a raw TLS 1.0–1.2 ClientHello with a single +// legacy cipher suite and returns true if the server accepts it. +func probeLegacyCipher(ctx context.Context, input cipherProbeInput) bool { + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", input.addr) + if err != nil { + return false + } + defer func() { _ = conn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = conn.SetDeadline(deadline) + } + + msg, err := buildLegacyClientHelloMsg(legacyClientHelloInput{ + serverName: input.serverName, + cipherSuites: []uint16{input.cipherID}, + }) + if err != nil { + return false + } + + if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { + return false + } + + result, err := readServerHello(conn) + if err != nil { + return false + } + + return result.version <= tls.VersionTLS12 && result.cipherSuite == input.cipherID +} + +// maxCertificatePayload is the maximum total bytes we'll read from the server +// while scanning for handshake messages (ServerHello + Certificate). This +// bounds memory usage when probing untrusted servers. +const maxCertificatePayload = 128 * 1024 + +// readServerCertificates reads TLS handshake records from r and extracts the +// ServerHello and Certificate messages. It stops after finding the Certificate +// message, encountering ServerHelloDone (0x0E), or receiving an Alert. +// +// The function handles multiple handshake messages packed into a single TLS +// record and handshake messages spanning multiple records. +func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificate, error) { + var shResult *serverHelloResult + var certs []*x509.Certificate + + // Accumulate handshake data across records — a single handshake message + // may span multiple TLS records. + var handshakeBuf []byte + totalRead := 0 + + for { + if totalRead > maxCertificatePayload { + return shResult, certs, fmt.Errorf("exceeded %d byte limit reading server handshake", maxCertificatePayload) + } + + // Read TLS record header (5 bytes): type(1) + version(2) + length(2). + header := make([]byte, 5) + if _, err := io.ReadFull(r, header); err != nil { + if shResult != nil { + return shResult, certs, fmt.Errorf("reading TLS record: %w", err) + } + return nil, nil, fmt.Errorf("reading TLS record header: %w", err) + } + totalRead += 5 + + contentType := header[0] + recordLen := int(binary.BigEndian.Uint16(header[3:5])) + + if recordLen > 16640 { + return shResult, certs, fmt.Errorf("TLS record too large: %d bytes", recordLen) + } + + payload := make([]byte, recordLen) + if _, err := io.ReadFull(r, payload); err != nil { + return shResult, certs, fmt.Errorf("reading TLS record payload: %w", err) + } + totalRead += recordLen + + // Alert record — server rejected something. + if contentType == 0x15 { + if shResult != nil { + return shResult, certs, errAlertReceived + } + return nil, nil, errAlertReceived + } + + if contentType != 0x16 { + return shResult, certs, fmt.Errorf("unexpected TLS content type: 0x%02x", contentType) + } + + // Append to handshake buffer and process complete messages. + handshakeBuf = append(handshakeBuf, payload...) + + for len(handshakeBuf) >= 4 { + hsType := handshakeBuf[0] + hsLen := int(handshakeBuf[1])<<16 | int(handshakeBuf[2])<<8 | int(handshakeBuf[3]) + + if len(handshakeBuf) < 4+hsLen { + break // incomplete message, need more records + } + + hsMsg := handshakeBuf[:4+hsLen] + handshakeBuf = handshakeBuf[4+hsLen:] + + switch hsType { + case 0x02: // ServerHello + sh, err := parseServerHello(hsMsg) + if err != nil { + return nil, nil, fmt.Errorf("parsing ServerHello: %w", err) + } + shResult = sh + + case 0x0B: // Certificate + parsed, err := parseCertificateMessage(hsMsg[4:]) // skip handshake header + if err != nil { + return shResult, nil, fmt.Errorf("parsing Certificate message: %w", err) + } + certs = parsed + return shResult, certs, nil + + case 0x0E: // ServerHelloDone + return shResult, certs, nil + } + } + } +} + +// parseCertificateMessage parses the body of a TLS Certificate handshake message. +// The format is: total_length(3) + [cert_length(3) + cert_der(...)]* +func parseCertificateMessage(data []byte) ([]*x509.Certificate, error) { + if len(data) < 3 { + return nil, fmt.Errorf("certificate message too short: %d bytes", len(data)) + } + + totalLen := int(data[0])<<16 | int(data[1])<<8 | int(data[2]) + data = data[3:] + if len(data) < totalLen { + return nil, fmt.Errorf("certificate message truncated: need %d bytes, have %d", totalLen, len(data)) + } + data = data[:totalLen] + + var certs []*x509.Certificate + for len(data) > 0 { + if len(data) < 3 { + return certs, fmt.Errorf("truncated certificate entry") + } + certLen := int(data[0])<<16 | int(data[1])<<8 | int(data[2]) + data = data[3:] + if len(data) < certLen { + return certs, fmt.Errorf("certificate entry truncated: need %d bytes, have %d", certLen, len(data)) + } + cert, err := x509.ParseCertificate(data[:certLen]) + if err != nil { + return certs, fmt.Errorf("parsing certificate: %w", err) + } + certs = append(certs, cert) + data = data[certLen:] + } + + return certs, nil +} + +// legacyFallbackInput contains parameters for a legacy TLS fallback connection. +type legacyFallbackInput struct { + addr string + serverName string +} + +// legacyFallbackResult contains the result of a legacy TLS fallback connection. +type legacyFallbackResult struct { + version uint16 + cipherSuite uint16 + certificates []*x509.Certificate +} + +// legacyFallbackConnect attempts a raw TLS handshake offering all legacy cipher +// suites plus Go's insecure cipher suites. It reads through the ServerHello and +// Certificate messages to extract the server's certificate chain. This is used +// as a fallback when Go's crypto/tls cannot handshake (e.g. DHE-only servers). +func legacyFallbackConnect(ctx context.Context, input legacyFallbackInput) (*legacyFallbackResult, error) { + // Collect all cipher suites: legacy DHE/DHE-DSS + Go's insecure suites. + var allSuites []uint16 + for _, def := range legacyCipherSuites { + allSuites = append(allSuites, def.ID) + } + for _, cs := range tls.InsecureCipherSuites() { + allSuites = append(allSuites, cs.ID) + } + // Also include Go's standard TLS 1.2 suites for maximum compatibility. + for _, cs := range tls.CipherSuites() { + allSuites = append(allSuites, cs.ID) + } + + dialer := &net.Dialer{} + conn, err := dialer.DialContext(ctx, "tcp", input.addr) + if err != nil { + return nil, fmt.Errorf("connecting to %s: %w", input.addr, err) + } + defer func() { _ = conn.Close() }() + + if deadline, ok := ctx.Deadline(); ok { + _ = conn.SetDeadline(deadline) + } + + msg, err := buildLegacyClientHelloMsg(legacyClientHelloInput{ + serverName: input.serverName, + cipherSuites: allSuites, + }) + if err != nil { + return nil, fmt.Errorf("building legacy ClientHello: %w", err) + } + + if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { + return nil, fmt.Errorf("sending legacy ClientHello: %w", err) + } + + shResult, certs, err := readServerCertificates(conn) + if err != nil { + return nil, fmt.Errorf("reading server certificates: %w", err) + } + if shResult == nil { + return nil, fmt.Errorf("no ServerHello received") + } + if len(certs) == 0 { + return nil, fmt.Errorf("no certificates received from server") + } + + return &legacyFallbackResult{ + version: shResult.version, + cipherSuite: shResult.cipherSuite, + certificates: certs, + }, nil +} + +// legacyCipherSuiteName returns a human-readable name for a cipher suite, +// checking the legacy cipher registry first, then falling back to +// cipherSuiteName (which covers Go's known suites and TLS 1.3 CCM suites). +func legacyCipherSuiteName(id uint16) string { + for _, def := range legacyCipherSuites { + if def.ID == id { + return def.Name + } + } + return cipherSuiteName(id) +} diff --git a/legacyprobe_test.go b/legacyprobe_test.go new file mode 100644 index 0000000..61f08c1 --- /dev/null +++ b/legacyprobe_test.go @@ -0,0 +1,491 @@ +package certkit + +import ( + "bytes" + "crypto/ecdsa" + "crypto/elliptic" + "crypto/rand" + "crypto/x509" + "crypto/x509/pkix" + "encoding/binary" + "math/big" + "net" + "testing" + "time" +) + +func TestBuildLegacyClientHelloMsg(t *testing.T) { + t.Parallel() + + tests := []struct { + name string + input legacyClientHelloInput + wantErr bool + }{ + { + name: "single cipher suite with SNI", + input: legacyClientHelloInput{ + serverName: "example.com", + cipherSuites: []uint16{0x0033}, + }, + }, + { + name: "multiple cipher suites", + input: legacyClientHelloInput{ + serverName: "test.example.com", + cipherSuites: []uint16{0x0033, 0x0039, 0x009E}, + }, + }, + { + name: "no server name", + input: legacyClientHelloInput{ + cipherSuites: []uint16{0x0033}, + }, + }, + { + name: "no cipher suites", + input: legacyClientHelloInput{ + serverName: "example.com", + }, + wantErr: true, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + msg, err := buildLegacyClientHelloMsg(tt.input) + if tt.wantErr { + if err == nil { + t.Fatal("expected error, got nil") + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + + // Verify it's a valid handshake message. + if len(msg) < 4 { + t.Fatalf("message too short: %d bytes", len(msg)) + } + if msg[0] != 0x01 { + t.Errorf("handshake type = 0x%02x, want 0x01 (ClientHello)", msg[0]) + } + + // Parse handshake length. + hsLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) + if len(msg) != 4+hsLen { + t.Fatalf("handshake length mismatch: header says %d, actual body is %d", hsLen, len(msg)-4) + } + + body := msg[4:] + + // Legacy version should be TLS 1.2 (0x0303). + if body[0] != 0x03 || body[1] != 0x03 { + t.Errorf("legacy version = 0x%02x%02x, want 0x0303 (TLS 1.2)", body[0], body[1]) + } + + // Client random: 32 bytes at offset 2. + pos := 2 + 32 + + // Session ID: should be empty (length 0). + sessionIDLen := int(body[pos]) + pos++ + if sessionIDLen != 0 { + t.Errorf("session ID length = %d, want 0", sessionIDLen) + } + pos += sessionIDLen + + // Cipher suites length. + csLen := int(binary.BigEndian.Uint16(body[pos : pos+2])) + pos += 2 + wantCSLen := len(tt.input.cipherSuites) * 2 + if csLen != wantCSLen { + t.Errorf("cipher suites length = %d, want %d", csLen, wantCSLen) + } + + // Verify cipher suite values. + for i, wantCS := range tt.input.cipherSuites { + gotCS := binary.BigEndian.Uint16(body[pos+i*2 : pos+i*2+2]) + if gotCS != wantCS { + t.Errorf("cipher suite[%d] = 0x%04x, want 0x%04x", i, gotCS, wantCS) + } + } + pos += csLen + + // Compression methods: 1 byte length, 1 byte null. + if body[pos] != 1 || body[pos+1] != 0 { + t.Errorf("compression = [%d, %d], want [1, 0]", body[pos], body[pos+1]) + } + pos += 2 + + // Extensions. + if pos+2 > len(body) { + t.Fatal("body truncated at extensions length") + } + extLen := int(binary.BigEndian.Uint16(body[pos : pos+2])) + pos += 2 + if pos+extLen != len(body) { + t.Fatalf("extensions length mismatch: says %d, remaining is %d", extLen, len(body)-pos) + } + + // Parse extensions and check for expected/unexpected types. + extData := body[pos:] + foundSNI := false + foundSigAlg := false + foundECPointFormats := false + for len(extData) >= 4 { + extType := binary.BigEndian.Uint16(extData[0:2]) + extDataLen := int(binary.BigEndian.Uint16(extData[2:4])) + if 4+extDataLen > len(extData) { + t.Fatalf("extension truncated: type 0x%04x, length %d", extType, extDataLen) + } + + switch extType { + case 0x0000: + foundSNI = true + case 0x000d: + foundSigAlg = true + case 0x000b: + foundECPointFormats = true + case 0x002b: // supported_versions — TLS 1.3 only + t.Error("found supported_versions extension (0x002b) — should not be in legacy ClientHello") + case 0x0033: // key_share — TLS 1.3 only + t.Error("found key_share extension (0x0033) — should not be in legacy ClientHello") + case 0x002d: // psk_key_exchange_modes — TLS 1.3 only + t.Error("found psk_key_exchange_modes extension (0x002d) — should not be in legacy ClientHello") + } + + extData = extData[4+extDataLen:] + } + + if tt.input.serverName != "" && !foundSNI { + t.Error("SNI extension not found") + } + if tt.input.serverName == "" && foundSNI { + t.Error("SNI extension present but no server name specified") + } + if !foundSigAlg { + t.Error("signature_algorithms extension not found") + } + if !foundECPointFormats { + t.Error("ec_point_formats extension not found") + } + }) + } +} + +func TestParseCertificateMessage(t *testing.T) { + t.Parallel() + + // Generate a test certificate. + key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) + if err != nil { + t.Fatal(err) + } + template := &x509.Certificate{ + SerialNumber: big.NewInt(1), + Subject: pkix.Name{CommonName: "test"}, + NotBefore: time.Now().Add(-time.Hour), + NotAfter: time.Now().Add(time.Hour), + } + certDER, err := x509.CreateCertificate(rand.Reader, template, template, &key.PublicKey, key) + if err != nil { + t.Fatal(err) + } + + tests := []struct { + name string + data []byte + wantCerts int + wantErr bool + }{ + { + name: "single certificate", + data: buildCertificateMessageBody(certDER), + wantCerts: 1, + }, + { + name: "two certificates", + data: buildCertificateMessageBody(certDER, certDER), + wantCerts: 2, + }, + { + name: "empty certificate list", + data: []byte{0, 0, 0}, // total_len = 0 + wantCerts: 0, + }, + { + name: "truncated header", + data: []byte{0, 0}, + wantErr: true, + }, + { + name: "truncated certificate entry", + data: []byte{0, 0, 10, 0, 0, 5, 1, 2, 3}, // claims 5 bytes but only 3 + wantErr: true, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + certs, err := parseCertificateMessage(tt.data) + if tt.wantErr { + if err == nil { + t.Fatal("expected error, got nil") + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if len(certs) != tt.wantCerts { + t.Errorf("got %d certificates, want %d", len(certs), tt.wantCerts) + } + }) + } +} + +// buildCertificateMessageBody constructs a TLS Certificate message body +// from DER-encoded certificates. +func buildCertificateMessageBody(certs ...[]byte) []byte { + var entries []byte + for _, cert := range certs { + entries = appendUint24(entries, uint32(len(cert))) + entries = append(entries, cert...) + } + var body []byte + body = appendUint24(body, uint32(len(entries))) + body = append(body, entries...) + return body +} + +func TestReadServerCertificates(t *testing.T) { + t.Parallel() + + // Generate a test CA and leaf certificate. + key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) + if err != nil { + t.Fatal(err) + } + template := &x509.Certificate{ + SerialNumber: big.NewInt(42), + Subject: pkix.Name{CommonName: "readcerts-test"}, + NotBefore: time.Now().Add(-time.Hour), + NotAfter: time.Now().Add(time.Hour), + } + certDER, err := x509.CreateCertificate(rand.Reader, template, template, &key.PublicKey, key) + if err != nil { + t.Fatal(err) + } + + // Build a ServerHello handshake message (cipher 0x0033, TLS 1.2). + serverHello := buildMockServerHello(0x0303, 0x0033) + + // Build a Certificate handshake message. + certMsg := buildCertificateHandshakeMessage(certDER) + + tests := []struct { + name string + records []byte + wantCS uint16 + wantVer uint16 + wantCerts int + wantErr bool + }{ + { + name: "single record with ServerHello + Certificate", + records: wrapTLSRecord(append(serverHello, certMsg...)), + wantCS: 0x0033, + wantVer: 0x0303, + wantCerts: 1, + }, + { + name: "separate records for ServerHello and Certificate", + records: append(wrapTLSRecord(serverHello), wrapTLSRecord(certMsg)...), + wantCS: 0x0033, + wantVer: 0x0303, + wantCerts: 1, + }, + { + name: "alert record", + records: buildAlertRecord(), + wantErr: true, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + r := bytes.NewReader(tt.records) + sh, certs, err := readServerCertificates(r) + if tt.wantErr { + if err == nil { + t.Fatal("expected error, got nil") + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if sh == nil { + t.Fatal("ServerHello result is nil") + } + if sh.cipherSuite != tt.wantCS { + t.Errorf("cipher suite = 0x%04x, want 0x%04x", sh.cipherSuite, tt.wantCS) + } + if sh.version != tt.wantVer { + t.Errorf("version = 0x%04x, want 0x%04x", sh.version, tt.wantVer) + } + if len(certs) != tt.wantCerts { + t.Errorf("got %d certificates, want %d", len(certs), tt.wantCerts) + } + if tt.wantCerts > 0 { + if certs[0].Subject.CommonName != "readcerts-test" { + t.Errorf("cert CN = %q, want %q", certs[0].Subject.CommonName, "readcerts-test") + } + } + }) + } +} + +// buildMockServerHello builds a minimal ServerHello handshake message. +func buildMockServerHello(version, cipherSuite uint16) []byte { + var body []byte + // Version (2 bytes). + body = appendUint16(body, version) + // Server random (32 bytes). + body = append(body, make([]byte, 32)...) + // Session ID: empty. + body = append(body, 0x00) + // Cipher suite. + body = appendUint16(body, cipherSuite) + // Compression method: null. + body = append(body, 0x00) + + // Wrap in handshake header: type 0x02 (ServerHello). + msg := []byte{0x02} + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg +} + +// buildCertificateHandshakeMessage builds a TLS Certificate handshake message. +func buildCertificateHandshakeMessage(certs ...[]byte) []byte { + body := buildCertificateMessageBody(certs...) + msg := []byte{0x0B} // Certificate + msg = appendUint24(msg, uint32(len(body))) + msg = append(msg, body...) + return msg +} + +// buildAlertRecord builds a TLS Alert record. +func buildAlertRecord() []byte { + // Alert: handshake_failure (40), fatal (2). + payload := []byte{0x02, 0x28} + record := []byte{0x15} // ContentType: Alert + record = append(record, 0x03, 0x01) + record = appendUint16(record, uint16(len(payload))) + record = append(record, payload...) + return record +} + +func TestLegacyFallbackConnect(t *testing.T) { + t.Parallel() + + // Start a mock server that speaks raw TLS: sends ServerHello + Certificate + // at the byte level (no real TLS stack needed). + ca := generateTestCA(t, "Legacy Fallback CA") + leaf := generateTestLeafCert(t, ca) + + // Parse the leaf cert so we can check the CN. + leafCert, err := x509.ParseCertificate(leaf.DER) + if err != nil { + t.Fatal(err) + } + + // Start a TCP listener that responds with raw TLS records. + listener, err := net.Listen("tcp", "127.0.0.1:0") + if err != nil { + t.Fatal(err) + } + t.Cleanup(func() { _ = listener.Close() }) + + go func() { + for { + conn, err := listener.Accept() + if err != nil { + return + } + // Read the ClientHello (we don't parse it, just consume it). + buf := make([]byte, 4096) + _, _ = conn.Read(buf) + + // Send ServerHello + Certificate as raw TLS records. + serverHello := buildMockServerHello(0x0303, 0x0033) + certMsg := buildCertificateHandshakeMessage(leaf.DER) + helloDone := []byte{0x0E, 0x00, 0x00, 0x00} // ServerHelloDone + + // Pack all handshake messages into a single TLS record. + var handshake []byte + handshake = append(handshake, serverHello...) + handshake = append(handshake, certMsg...) + handshake = append(handshake, helloDone...) + + _, _ = conn.Write(wrapTLSRecord(handshake)) + _ = conn.Close() + } + }() + + _, port, err := net.SplitHostPort(listener.Addr().String()) + if err != nil { + t.Fatal(err) + } + + result, err := legacyFallbackConnect(t.Context(), legacyFallbackInput{ + addr: net.JoinHostPort("127.0.0.1", port), + serverName: "localhost", + }) + if err != nil { + t.Fatalf("legacyFallbackConnect failed: %v", err) + } + + if result.version != 0x0303 { + t.Errorf("version = 0x%04x, want 0x0303", result.version) + } + if result.cipherSuite != 0x0033 { + t.Errorf("cipher suite = 0x%04x, want 0x0033", result.cipherSuite) + } + if len(result.certificates) != 1 { + t.Fatalf("got %d certificates, want 1", len(result.certificates)) + } + if result.certificates[0].Subject.CommonName != leafCert.Subject.CommonName { + t.Errorf("cert CN = %q, want %q", result.certificates[0].Subject.CommonName, leafCert.Subject.CommonName) + } +} + +func TestLegacyCipherSuiteName(t *testing.T) { + t.Parallel() + + tests := []struct { + id uint16 + want string + }{ + {0x0033, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA"}, + {0x009E, "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256"}, + {0x0032, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA"}, + {0x1301, "TLS_AES_128_GCM_SHA256"}, // Falls through to cipherSuiteName + } + + for _, tt := range tests { + t.Run(tt.want, func(t *testing.T) { + t.Parallel() + got := legacyCipherSuiteName(tt.id) + if got != tt.want { + t.Errorf("legacyCipherSuiteName(0x%04x) = %q, want %q", tt.id, got, tt.want) + } + }) + } +} From 910b9777191e4d15753da0551794b14612911448 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 13:22:38 -0500 Subject: [PATCH 18/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20fallback=20timeout,=20dedup=20diagnostics,=20remove?= =?UTF-8?q?=20dead=20code?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Add dedicated 5s timeout for legacy fallback connection to prevent indefinite blocking when a server stalls - Deduplicate diagnostics when --ciphers is used: scan-level diagnostics supersede negotiated-cipher diagnostics by check name - Remove redundant legacyCipherSuiteName — cipherSuiteName already covers legacy IDs - Add cross-record Certificate message test (spanning two TLS records) - Check errAlertReceived sentinel in alert test instead of generic error Co-Authored-By: Claude Opus 4.6 --- cmd/certkit/connect.go | 16 +++++++++++++++- connect.go | 11 +++++++++-- legacyprobe.go | 12 ------------ legacyprobe_test.go | 35 ++++++++++++++++++++++++++--------- 4 files changed, 50 insertions(+), 24 deletions(-) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index 94f7ba9..863596e 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -141,7 +141,21 @@ func runConnect(cmd *cobra.Command, args []string) error { return fmt.Errorf("scanning cipher suites for %s: %w", args[0], scanErr) } result.CipherScan = cipherScan - result.Diagnostics = append(result.Diagnostics, certkit.DiagnoseCipherScan(cipherScan)...) + scanDiags := certkit.DiagnoseCipherScan(cipherScan) + // Scan diagnostics supersede negotiated-cipher diagnostics + // (same check names but more comprehensive — aggregate vs. single). + // Remove negotiated-cipher diagnostics that the scan covers. + scanChecks := make(map[string]bool, len(scanDiags)) + for _, d := range scanDiags { + scanChecks[d.Check] = true + } + filtered := result.Diagnostics[:0] + for _, d := range result.Diagnostics { + if !scanChecks[d.Check] { + filtered = append(filtered, d) + } + } + result.Diagnostics = append(filtered, scanDiags...) } spin.Stop() diff --git a/connect.go b/connect.go index dca24d3..a2dcaa9 100644 --- a/connect.go +++ b/connect.go @@ -316,9 +316,16 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err handshakeErr := tlsConn.HandshakeContext(ctx) if handshakeErr != nil && clientAuth == nil { + // Close the failed TLS connection before opening a new one. + // The deferred tlsConn.Close() will be a no-op after this. _ = tlsConn.Close() + // Try raw legacy handshake to detect DHE/static-RSA-only servers. - legacyResult, legacyErr := legacyFallbackConnect(ctx, legacyFallbackInput{ + // Use a dedicated timeout so a stalling server can't hold the + // fallback connection open indefinitely. + fallbackCtx, fallbackCancel := context.WithTimeout(ctx, 5*time.Second) + defer fallbackCancel() + legacyResult, legacyErr := legacyFallbackConnect(fallbackCtx, legacyFallbackInput{ addr: addr, serverName: serverName, }) @@ -329,7 +336,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err Host: input.Host, Port: port, Protocol: tlsVersionString(legacyResult.version), - CipherSuite: legacyCipherSuiteName(legacyResult.cipherSuite), + CipherSuite: cipherSuiteName(legacyResult.cipherSuite), ServerName: serverName, PeerChain: legacyResult.certificates, LegacyProbe: true, diff --git a/legacyprobe.go b/legacyprobe.go index 964b2c3..47f98b3 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -355,15 +355,3 @@ func legacyFallbackConnect(ctx context.Context, input legacyFallbackInput) (*leg certificates: certs, }, nil } - -// legacyCipherSuiteName returns a human-readable name for a cipher suite, -// checking the legacy cipher registry first, then falling back to -// cipherSuiteName (which covers Go's known suites and TLS 1.3 CCM suites). -func legacyCipherSuiteName(id uint16) string { - for _, def := range legacyCipherSuites { - if def.ID == id { - return def.Name - } - } - return cipherSuiteName(id) -} diff --git a/legacyprobe_test.go b/legacyprobe_test.go index 61f08c1..fa4496d 100644 --- a/legacyprobe_test.go +++ b/legacyprobe_test.go @@ -8,6 +8,7 @@ import ( "crypto/x509" "crypto/x509/pkix" "encoding/binary" + "errors" "math/big" "net" "testing" @@ -287,13 +288,19 @@ func TestReadServerCertificates(t *testing.T) { // Build a Certificate handshake message. certMsg := buildCertificateHandshakeMessage(certDER) + // Build a Certificate handshake message that spans two records by splitting + // mid-message. This exercises the "incomplete message, need more records" + // branch in readServerCertificates. + certMsgSplit1 := certMsg[:len(certMsg)/2] + certMsgSplit2 := certMsg[len(certMsg)/2:] + tests := []struct { name string records []byte wantCS uint16 wantVer uint16 wantCerts int - wantErr bool + wantErr error // nil means no error; non-nil checked with errors.Is }{ { name: "single record with ServerHello + Certificate", @@ -309,10 +316,20 @@ func TestReadServerCertificates(t *testing.T) { wantVer: 0x0303, wantCerts: 1, }, + { + name: "Certificate message spanning two records", + records: append( + wrapTLSRecord(serverHello), + append(wrapTLSRecord(certMsgSplit1), wrapTLSRecord(certMsgSplit2)...)..., + ), + wantCS: 0x0033, + wantVer: 0x0303, + wantCerts: 1, + }, { name: "alert record", records: buildAlertRecord(), - wantErr: true, + wantErr: errAlertReceived, }, } @@ -321,9 +338,9 @@ func TestReadServerCertificates(t *testing.T) { t.Parallel() r := bytes.NewReader(tt.records) sh, certs, err := readServerCertificates(r) - if tt.wantErr { - if err == nil { - t.Fatal("expected error, got nil") + if tt.wantErr != nil { + if !errors.Is(err, tt.wantErr) { + t.Fatalf("error = %v, want %v", err, tt.wantErr) } return } @@ -466,7 +483,7 @@ func TestLegacyFallbackConnect(t *testing.T) { } } -func TestLegacyCipherSuiteName(t *testing.T) { +func TestCipherSuiteNameLegacyIDs(t *testing.T) { t.Parallel() tests := []struct { @@ -476,15 +493,15 @@ func TestLegacyCipherSuiteName(t *testing.T) { {0x0033, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA"}, {0x009E, "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256"}, {0x0032, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA"}, - {0x1301, "TLS_AES_128_GCM_SHA256"}, // Falls through to cipherSuiteName + {0x1301, "TLS_AES_128_GCM_SHA256"}, // Standard suite via Go's registry } for _, tt := range tests { t.Run(tt.want, func(t *testing.T) { t.Parallel() - got := legacyCipherSuiteName(tt.id) + got := cipherSuiteName(tt.id) if got != tt.want { - t.Errorf("legacyCipherSuiteName(0x%04x) = %q, want %q", tt.id, got, tt.want) + t.Errorf("cipherSuiteName(0x%04x) = %q, want %q", tt.id, got, tt.want) } }) } From 86c3a89350d0bee1513e1220dd8a8def7590f21e Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 13:36:41 -0500 Subject: [PATCH 19/30] =?UTF-8?q?fix:=20address=20PR=20review=20comments?= =?UTF-8?q?=20=E2=80=94=20error=20wrapping,=20lowercase=20errors,=20doc=20?= =?UTF-8?q?fix?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Wrap all bare error returns in generateKeyShare with context (ERR-1) - Lowercase "ClientHello", "ServerHello", "Certificate" in error strings (ERR-4) - Fix probeQUICCipher doc comment: says "UDP 443" but actually uses input.addr Co-Authored-By: Claude Opus 4.6 --- legacyprobe.go | 6 +++--- quicprobe.go | 4 ++-- tls13probe.go | 20 ++++++++++---------- 3 files changed, 15 insertions(+), 15 deletions(-) diff --git a/legacyprobe.go b/legacyprobe.go index 47f98b3..6b517ea 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -62,7 +62,7 @@ type legacyClientHelloInput struct { // supported_versions, key_share, or psk_key_exchange_modes extensions. func buildLegacyClientHelloMsg(input legacyClientHelloInput) ([]byte, error) { if len(input.cipherSuites) == 0 { - return nil, fmt.Errorf("building legacy ClientHello: no cipher suites specified") + return nil, fmt.Errorf("building legacy client hello: no cipher suites specified") } // Build extensions. @@ -230,14 +230,14 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat case 0x02: // ServerHello sh, err := parseServerHello(hsMsg) if err != nil { - return nil, nil, fmt.Errorf("parsing ServerHello: %w", err) + return nil, nil, fmt.Errorf("parsing server hello: %w", err) } shResult = sh case 0x0B: // Certificate parsed, err := parseCertificateMessage(hsMsg[4:]) // skip handshake header if err != nil { - return shResult, nil, fmt.Errorf("parsing Certificate message: %w", err) + return shResult, nil, fmt.Errorf("parsing certificate message: %w", err) } certs = parsed return shResult, certs, nil diff --git a/quicprobe.go b/quicprobe.go index c22c74c..0752d09 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -464,8 +464,8 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return nil, fmt.Errorf("no CRYPTO frame found in QUIC Initial response") } -// probeQUICCipher sends a QUIC Initial packet to UDP 443 with a single -// cipher suite and returns true if the server accepts it. +// probeQUICCipher sends a QUIC Initial packet to the provided UDP address +// with a single cipher suite and returns true if the server accepts it. func probeQUICCipher(ctx context.Context, input cipherProbeInput) bool { // Generate random connection IDs. dcid := make([]byte, 8) diff --git a/tls13probe.go b/tls13probe.go index 729d550..6e388f3 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -176,28 +176,28 @@ func generateKeyShare(groupID tls.CurveID) ([]byte, error) { case tls.X25519: key, err := ecdh.X25519().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating X25519 key: %w", err) } return key.PublicKey().Bytes(), nil case tls.CurveP256: key, err := ecdh.P256().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating P-256 key: %w", err) } return key.PublicKey().Bytes(), nil case tls.CurveP384: key, err := ecdh.P384().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating P-384 key: %w", err) } return key.PublicKey().Bytes(), nil case tls.CurveP521: key, err := ecdh.P521().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating P-521 key: %w", err) } return key.PublicKey().Bytes(), nil @@ -206,11 +206,11 @@ func generateKeyShare(groupID tls.CurveID) ([]byte, error) { // See draft-ietf-tls-ecdhe-mlkem-02 §4.1 and Go crypto/tls/key_schedule.go:184. dk, err := mlkem.GenerateKey768() if err != nil { - return nil, err + return nil, fmt.Errorf("generating ML-KEM-768 key: %w", err) } x, err := ecdh.X25519().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating X25519 key for X25519MLKEM768: %w", err) } return append(dk.EncapsulationKey().Bytes(), x.PublicKey().Bytes()...), nil @@ -218,11 +218,11 @@ func generateKeyShare(groupID tls.CurveID) ([]byte, error) { // SecP256r1MLKEM768: ECDH (P-256) first, then ML-KEM-768. ec, err := ecdh.P256().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating P-256 key for SecP256r1MLKEM768: %w", err) } dk, err := mlkem.GenerateKey768() if err != nil { - return nil, err + return nil, fmt.Errorf("generating ML-KEM-768 key for SecP256r1MLKEM768: %w", err) } return append(ec.PublicKey().Bytes(), dk.EncapsulationKey().Bytes()...), nil @@ -230,11 +230,11 @@ func generateKeyShare(groupID tls.CurveID) ([]byte, error) { // SecP384r1MLKEM1024: ECDH (P-384) first, then ML-KEM-1024. ec, err := ecdh.P384().GenerateKey(rand.Reader) if err != nil { - return nil, err + return nil, fmt.Errorf("generating P-384 key for SecP384r1MLKEM1024: %w", err) } dk, err := mlkem.GenerateKey1024() if err != nil { - return nil, err + return nil, fmt.Errorf("generating ML-KEM-1024 key for SecP384r1MLKEM1024: %w", err) } return append(ec.PublicKey().Bytes(), dk.EncapsulationKey().Bytes()...), nil From a59b41e083fc5e9539efdbc8180576985f2b0496 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 13:38:27 -0500 Subject: [PATCH 20/30] =?UTF-8?q?docs:=20update=20PR=20feedback=20rules=20?= =?UTF-8?q?=E2=80=94=20reply,=20resolve,=20and=20minimize?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add minimize step to PR feedback workflow. Expand GraphQL query to fetch both review thread and conversation comment node IDs. Co-Authored-By: Claude Opus 4.6 --- .claude/rules/commits-and-prs.md | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/.claude/rules/commits-and-prs.md b/.claude/rules/commits-and-prs.md index abb2396..268a66d 100644 --- a/.claude/rules/commits-and-prs.md +++ b/.claude/rules/commits-and-prs.md @@ -55,28 +55,41 @@ When a pre-commit hook modifies files (e.g., goimports reformats struct alignmen This is especially common with `goimports` reformatting Go files. -## Resolving PR review threads +## Addressing PR feedback -When addressing review feedback, both reply AND resolve: +When working on a PR, address **both** PR review comments (on diffs) and issue-style comments (on the PR conversation). For each piece of feedback: -1. **Reply** via REST: `gh api repos/OWNER/REPO/pulls/N/comments -X POST -F body="..." -F in_reply_to=COMMENT_ID` -2. **Resolve** via GraphQL: `gh api graphql -f query='mutation { resolveReviewThread(input: {threadId: "THREAD_ID"}) { thread { isResolved } } }'` +1. **Fix the code** — make the requested change or explain why not +2. **Reply** explaining what was done: `gh api repos/OWNER/REPO/pulls/N/comments -X POST -F body="..." -F in_reply_to=COMMENT_ID` +3. **Resolve** the thread: `gh api graphql -f query='mutation { resolveReviewThread(input: {threadId: "THREAD_ID"}) { thread { isResolved } } }'` +4. **Minimize** addressed comments to reduce noise: `gh api graphql -f query='mutation { minimizeComment(input: {subjectId: "COMMENT_NODE_ID", classifier: RESOLVED}) { minimizedComment { isMinimized } } }'` -To get thread IDs, query: +To get thread IDs and comment node IDs, query: ```sh gh api graphql -f query='{ repository(owner: "sensiblebit", name: "certkit") { pullRequest(number: N) { - reviewThreads(first: 20) { - nodes { id isResolved comments(first: 1) { nodes { body } } } + reviewThreads(first: 50) { + nodes { + id + isResolved + comments(first: 5) { + nodes { id databaseId body } + } + } + } + comments(first: 50) { + nodes { id databaseId body } } } } }' ``` -Just replying does NOT mark the thread as resolved in the GitHub UI. +For issue-style comments (PR conversation), use `minimizeComment` with the comment's node `id`. For review comments, reply + resolve + minimize. + +Just replying does NOT mark the thread as resolved or minimized in the GitHub UI — all three steps are required. ## Merging PRs From bed32dfcbec5e34a6cbf0b7f7280eeea0ba8b90e Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 15:29:55 -0500 Subject: [PATCH 21/30] =?UTF-8?q?fix:=20address=20PR=20review=20comments?= =?UTF-8?q?=20=E2=80=94=20error=20strings,=20QUIC=20versions,=20panic,=20d?= =?UTF-8?q?up=20context?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Lowercase remaining "ClientHello"/"ServerHello" in legacyprobe.go errors (ERR-4) - Add QUIC cipher versions to SupportedVersions set (versionSet was TCP-only) - Replace appendQUICVarint2 panic with fallback to appendQUICVarint for v>=16384 - Return ConnectTLS error directly in CLI to avoid duplicate context prefix - Use "cipher suite scan for %s" prefix to avoid duplication with ScanCipherSuites internal "scanning cipher suites: ..." wrapping Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 4 ++++ cmd/certkit/connect.go | 4 ++-- connect.go | 1 + legacyprobe.go | 6 +++--- quicprobe.go | 11 ++++++----- 5 files changed, 16 insertions(+), 10 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index ac5cee5..7e5b4a0 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -95,6 +95,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix `OverallRating`, `FormatCipherRatingLine`, and `DiagnoseCipherScan` ignoring QUIC ciphers — weak QUIC ciphers were excluded from the overall rating and diagnostic count ([#82]) - Fix data race on `spinner.started` — replace `bool` with `atomic.Bool` for safe concurrent access (CC-3) ([#82]) - Fix bare error returns in `deriveTrafficKeys` — wrap with `%w` context per ERR-1 ([#82]) +- Fix `SupportedVersions` missing QUIC-only TLS versions — QUIC cipher versions now added to version set alongside TCP ciphers ([`pending`]) +- Fix `appendQUICVarint2` panic on values ≥ 16384 — falls back to `appendQUICVarint` instead of panicking on unexpected input ([`pending`]) +- Fix duplicate error context in `connect` CLI — `ConnectTLS` error returned directly; `ScanCipherSuites` error uses non-repeating prefix ([`pending`]) +- Fix remaining uppercase protocol names in `legacyprobe.go` error strings (ERR-4) ([`pending`]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index 863596e..0e11e24 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -121,7 +121,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if err != nil { spin.Stop() - return fmt.Errorf("connecting to %s: %w", args[0], err) + return err } // Optional cipher suite enumeration. @@ -138,7 +138,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if scanErr != nil { spin.Stop() - return fmt.Errorf("scanning cipher suites for %s: %w", args[0], scanErr) + return fmt.Errorf("cipher suite scan for %s: %w", args[0], scanErr) } result.CipherScan = cipherScan scanDiags := certkit.DiagnoseCipherScan(cipherScan) diff --git a/connect.go b/connect.go index a2dcaa9..9eba7c1 100644 --- a/connect.go +++ b/connect.go @@ -1170,6 +1170,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher } } for _, r := range quicCiphers { + versionSet[r.Version] = true if ratingRank(r.Rating) > ratingRank(overall) { overall = r.Rating } diff --git a/legacyprobe.go b/legacyprobe.go index 6b517ea..bb036bc 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -331,11 +331,11 @@ func legacyFallbackConnect(ctx context.Context, input legacyFallbackInput) (*leg cipherSuites: allSuites, }) if err != nil { - return nil, fmt.Errorf("building legacy ClientHello: %w", err) + return nil, fmt.Errorf("building legacy client hello: %w", err) } if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { - return nil, fmt.Errorf("sending legacy ClientHello: %w", err) + return nil, fmt.Errorf("sending legacy client hello: %w", err) } shResult, certs, err := readServerCertificates(conn) @@ -343,7 +343,7 @@ func legacyFallbackConnect(ctx context.Context, input legacyFallbackInput) (*leg return nil, fmt.Errorf("reading server certificates: %w", err) } if shResult == nil { - return nil, fmt.Errorf("no ServerHello received") + return nil, fmt.Errorf("no server hello received") } if len(certs) == 0 { return nil, fmt.Errorf("no certificates received from server") diff --git a/quicprobe.go b/quicprobe.go index 0752d09..38482b0 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -561,13 +561,14 @@ func appendQUICVarint(b []byte, v uint64) []byte { } } -// appendQUICVarint2 appends a 2-byte QUIC varint (for values < 16384). -// Panics if v >= 16384 since that requires a 4-byte encoding. +// appendQUICVarint2 appends a 2-byte QUIC varint when v < 16384. +// Falls back to appendQUICVarint for larger values to avoid panicking +// on unexpected input from untrusted servers. func appendQUICVarint2(b []byte, v uint64) []byte { - if v >= 16384 { - panic(fmt.Sprintf("appendQUICVarint2: value %d exceeds 2-byte varint capacity (max 16383)", v)) + if v < 16384 { + return append(b, byte(0x40|v>>8), byte(v)) } - return append(b, byte(0x40|v>>8), byte(v)) + return appendQUICVarint(b, v) } // decodeQUICVarint decodes a QUIC variable-length integer and returns From 900d52628e255f4a863bf433f60640b2499c4537 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 15:44:59 -0500 Subject: [PATCH 22/30] =?UTF-8?q?fix:=20address=20adversarial=20review=20f?= =?UTF-8?q?indings=20=E2=80=94=20security=20bounds,=20UX,=20test=20coverag?= =?UTF-8?q?e?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - tighten maxCertificatePayload check in readServerCertificates: enforce limit before allocating record payload buffer (was checked at top of loop, allowing up to one extra 16KB allocation past the cap) - tighten QUIC ACK rangeCount cap: use len(plaintext)/2 since each range item requires at least 2 varint bytes (gap + range) - lowercase CRYPTO in quicprobe.go error strings (ERR-4) - add Note: and Verify: N/A to connect output for LegacyProbe results — replaces misleading Verify: OK for a raw handshake path - add readServerCertificates tests: oversized record, unexpected content type, ServerHelloDone-without-Certificate, alert-after-ServerHello, payload limit enforcement (T-8) - add FormatConnectResult/LegacyProbe test case - remove T-9 violation from TestCipherSuiteNameLegacyIDs (0x1301 tests stdlib routing, not certkit logic) Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 9 ++++ cmd/certkit/connect.go | 8 +++- connect.go | 8 +++- connect_test.go | 29 ++++++++++++ legacyprobe.go | 9 ++-- legacyprobe_test.go | 102 ++++++++++++++++++++++++++++++++++++++--- quicprobe.go | 12 ++--- 7 files changed, 158 insertions(+), 19 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 7e5b4a0..ae1bd7a 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -99,6 +99,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix `appendQUICVarint2` panic on values ≥ 16384 — falls back to `appendQUICVarint` instead of panicking on unexpected input ([`pending`]) - Fix duplicate error context in `connect` CLI — `ConnectTLS` error returned directly; `ScanCipherSuites` error uses non-repeating prefix ([`pending`]) - Fix remaining uppercase protocol names in `legacyprobe.go` error strings (ERR-4) ([`pending`]) +- Fix `readServerCertificates` totalRead check — enforce `maxCertificatePayload` limit before allocating record payload buffer, preventing over-allocation by a malicious server ([`pending`]) +- Fix QUIC ACK range count cap — use `len(plaintext)/2` instead of `len(plaintext)` since each range item requires at minimum 2 varint bytes ([`pending`]) +- Fix uppercase `CRYPTO` in `quicprobe.go` error strings — lowercase per ERR-4 ([`pending`]) +- Fix `connect` output showing misleading `Verify: OK` when result was obtained via raw legacy probe — now shows `Verify: N/A` and a `Note:` header line ([`pending`]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) @@ -193,6 +197,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Replace RC4 test case with unknown cipher ID (0xFFFF) in `TestRateCipherSuite` — tests conservative rating for unrecognized ciphers ([#82]) - Remove redundant `TestFormatCipherScanResult/single_cipher` and `TestFormatCipherRatingLine/TCP_good_QUIC_weak` — subsumed by stronger cases (T-14) ([#82]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) +- Add `TestReadServerCertificates` cases for oversized record, unexpected content type, and ServerHelloDone-without-Certificate paths (T-8) ([`pending`]) +- Add `TestReadServerCertificates_AlertAfterServerHello` — verifies ServerHello result is preserved when alert arrives after it ([`pending`]) +- Add `TestReadServerCertificates_PayloadLimit` — verifies `maxCertificatePayload` is enforced before allocation ([`pending`]) +- Add `TestFormatConnectResult/LegacyProbe` case — verifies Note and `Verify: N/A` appear for raw-probe results ([`pending`]) +- Remove T-9 violation from `TestCipherSuiteNameLegacyIDs` — `0x1301` (TLS_AES_128_GCM_SHA256) test was exercising stdlib routing, not certkit logic ([`pending`]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) - Add `TestCheckLeafCRL` table-driven tests covering revoked, good, expired CRL, wrong issuer, no CDPs, and non-HTTP CDPs ([#78]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index 0e11e24..ef1c720 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -285,11 +285,17 @@ func formatConnectVerbose(r *certkit.ConnectResult, now time.Time) string { fmt.Fprintf(&out, "Cipher Suite: %s\n", r.CipherSuite) fmt.Fprintf(&out, "Server Name: %s\n", r.ServerName) + if r.LegacyProbe { + out.WriteString("Note: certificate obtained via raw probe — server only supports legacy cipher suites\n") + } + if r.ALPN != "" { fmt.Fprintf(&out, "ALPN: %s\n", r.ALPN) } - if r.VerifyError != "" { + if r.LegacyProbe { + out.WriteString("Verify: N/A (raw handshake — certificate not cryptographically verified)\n") + } else if r.VerifyError != "" { fmt.Fprintf(&out, "Verify: FAILED (%s)\n", r.VerifyError) } else if r.AIAFetched { out.WriteString("Verify: OK (intermediates fetched via AIA)\n") diff --git a/connect.go b/connect.go index 9eba7c1..8f72762 100644 --- a/connect.go +++ b/connect.go @@ -1526,11 +1526,17 @@ func FormatConnectResult(r *ConnectResult) string { fmt.Fprintf(&out, "Cipher Suite: %s\n", r.CipherSuite) fmt.Fprintf(&out, "Server Name: %s\n", r.ServerName) + if r.LegacyProbe { + out.WriteString("Note: certificate obtained via raw probe — server only supports legacy cipher suites\n") + } + if r.ALPN != "" { fmt.Fprintf(&out, "ALPN: %s\n", r.ALPN) } - if r.VerifyError != "" { + if r.LegacyProbe { + out.WriteString("Verify: N/A (raw handshake — certificate not cryptographically verified)\n") + } else if r.VerifyError != "" { fmt.Fprintf(&out, "Verify: FAILED (%s)\n", r.VerifyError) } else if r.AIAFetched { out.WriteString("Verify: OK (intermediates fetched via AIA)\n") diff --git a/connect_test.go b/connect_test.go index e8588e2..75c25fd 100644 --- a/connect_test.go +++ b/connect_test.go @@ -420,6 +420,35 @@ func TestFormatConnectResult(t *testing.T) { }, } + // LegacyProbe cases are structurally different: the result has LegacyProbe=true. + t.Run("LegacyProbe shows Note and Verify N/A", func(t *testing.T) { + t.Parallel() + result := &ConnectResult{ + Host: "test.example.com", + Port: "443", + Protocol: "TLS 1.2", + CipherSuite: "TLS_DHE_RSA_WITH_AES_128_CBC_SHA", + ServerName: "test.example.com", + PeerChain: []*x509.Certificate{cert}, + LegacyProbe: true, + } + output := FormatConnectResult(result) + for _, want := range []string{ + "Note:", + "raw probe", + "Verify: N/A", + "not cryptographically verified", + } { + if !strings.Contains(output, want) { + t.Errorf("output missing %q\ngot:\n%s", want, output) + } + } + // Must NOT show "Verify: OK" for a legacy probe result. + if strings.Contains(output, "Verify: OK") { + t.Errorf("output contains misleading %q for LegacyProbe result\ngot:\n%s", "Verify: OK", output) + } + }) + for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { t.Parallel() diff --git a/legacyprobe.go b/legacyprobe.go index bb036bc..206922a 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -173,10 +173,6 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat totalRead := 0 for { - if totalRead > maxCertificatePayload { - return shResult, certs, fmt.Errorf("exceeded %d byte limit reading server handshake", maxCertificatePayload) - } - // Read TLS record header (5 bytes): type(1) + version(2) + length(2). header := make([]byte, 5) if _, err := io.ReadFull(r, header); err != nil { @@ -193,6 +189,11 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat if recordLen > 16640 { return shResult, certs, fmt.Errorf("TLS record too large: %d bytes", recordLen) } + // Check before allocating: a malicious server cannot force us to allocate + // more than maxCertificatePayload bytes even if record sizes are valid. + if totalRead+recordLen > maxCertificatePayload { + return shResult, certs, fmt.Errorf("exceeded %d byte limit reading server handshake", maxCertificatePayload) + } payload := make([]byte, recordLen) if _, err := io.ReadFull(r, payload); err != nil { diff --git a/legacyprobe_test.go b/legacyprobe_test.go index fa4496d..e5d1916 100644 --- a/legacyprobe_test.go +++ b/legacyprobe_test.go @@ -11,6 +11,7 @@ import ( "errors" "math/big" "net" + "strings" "testing" "time" ) @@ -294,13 +295,16 @@ func TestReadServerCertificates(t *testing.T) { certMsgSplit1 := certMsg[:len(certMsg)/2] certMsgSplit2 := certMsg[len(certMsg)/2:] + serverHelloDone := []byte{0x0E, 0x00, 0x00, 0x00} // ServerHelloDone handshake message + tests := []struct { - name string - records []byte - wantCS uint16 - wantVer uint16 - wantCerts int - wantErr error // nil means no error; non-nil checked with errors.Is + name string + records []byte + wantCS uint16 + wantVer uint16 + wantCerts int + wantErr error // checked with errors.Is (sentinel errors) + wantErrContains string // checked with strings.Contains (non-sentinel errors) }{ { name: "single record with ServerHello + Certificate", @@ -331,6 +335,23 @@ func TestReadServerCertificates(t *testing.T) { records: buildAlertRecord(), wantErr: errAlertReceived, }, + { + name: "ServerHelloDone without Certificate", + records: wrapTLSRecord(append(serverHello, serverHelloDone...)), + wantCS: 0x0033, + wantVer: 0x0303, + wantCerts: 0, + }, + { + name: "oversized TLS record", + records: buildRawTLSRecord(0x16, 16641), + wantErrContains: "TLS record too large", + }, + { + name: "unexpected content type", + records: buildRawTLSRecord(0x17, 1), // ApplicationData + wantErrContains: "unexpected TLS content type", + }, } for _, tt := range tests { @@ -344,6 +365,15 @@ func TestReadServerCertificates(t *testing.T) { } return } + if tt.wantErrContains != "" { + if err == nil { + t.Fatal("expected error, got nil") + } + if !strings.Contains(err.Error(), tt.wantErrContains) { + t.Fatalf("error = %v, want containing %q", err, tt.wantErrContains) + } + return + } if err != nil { t.Fatalf("unexpected error: %v", err) } @@ -368,6 +398,54 @@ func TestReadServerCertificates(t *testing.T) { } } +// TestReadServerCertificates_AlertAfterServerHello verifies that when an alert +// arrives after a ServerHello, the ServerHello result is still returned alongside +// the errAlertReceived sentinel. +func TestReadServerCertificates_AlertAfterServerHello(t *testing.T) { + t.Parallel() + serverHello := buildMockServerHello(0x0303, 0x0033) + records := append(wrapTLSRecord(serverHello), buildAlertRecord()...) + + sh, certs, err := readServerCertificates(bytes.NewReader(records)) + if !errors.Is(err, errAlertReceived) { + t.Fatalf("err = %v, want errAlertReceived", err) + } + if sh == nil { + t.Error("expected non-nil ServerHello result even when alert follows") + } + if len(certs) != 0 { + t.Errorf("expected 0 certs, got %d", len(certs)) + } +} + +// TestReadServerCertificates_PayloadLimit verifies that readServerCertificates +// rejects a stream that would exceed maxCertificatePayload before allocating +// the payload buffer. +func TestReadServerCertificates_PayloadLimit(t *testing.T) { + t.Parallel() + + // Generate records with ignored handshake messages (CertificateRequest, type 0x0D) + // totalling just over maxCertificatePayload bytes. + const chunkBody = 4000 + var chunkMsg []byte + chunkMsg = append(chunkMsg, 0x0D) // CertificateRequest — ignored by readServerCertificates + chunkMsg = appendUint24(chunkMsg, chunkBody) + chunkMsg = append(chunkMsg, make([]byte, chunkBody)...) + + var records []byte + for len(records) <= maxCertificatePayload { + records = append(records, wrapTLSRecord(chunkMsg)...) + } + + _, _, err := readServerCertificates(bytes.NewReader(records)) + if err == nil { + t.Fatal("expected error for payload exceeding limit, got nil") + } + if !strings.Contains(err.Error(), "exceeded") { + t.Errorf("error = %v, want containing %q", err, "exceeded") + } +} + // buildMockServerHello builds a minimal ServerHello handshake message. func buildMockServerHello(version, cipherSuite uint16) []byte { var body []byte @@ -398,6 +476,17 @@ func buildCertificateHandshakeMessage(certs ...[]byte) []byte { return msg } +// buildRawTLSRecord builds a TLS record with the given content type and a +// payload of payloadLen zero bytes. Unlike wrapTLSRecord it does NOT cap the +// payload size, so it can be used to construct intentionally oversized records +// for negative test cases. +func buildRawTLSRecord(contentType byte, payloadLen int) []byte { + record := []byte{contentType, 0x03, 0x03} + record = appendUint16(record, uint16(payloadLen)) + record = append(record, make([]byte, payloadLen)...) + return record +} + // buildAlertRecord builds a TLS Alert record. func buildAlertRecord() []byte { // Alert: handshake_failure (40), fatal (2). @@ -493,7 +582,6 @@ func TestCipherSuiteNameLegacyIDs(t *testing.T) { {0x0033, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA"}, {0x009E, "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256"}, {0x0032, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA"}, - {0x1301, "TLS_AES_128_GCM_SHA256"}, // Standard suite via Go's registry } for _, tt := range tests { diff --git a/quicprobe.go b/quicprobe.go index 38482b0..de9035e 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -395,8 +395,8 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve break } fpos += varLen - // Cap rangeCount to avoid CPU exhaustion on malicious packets. - if rangeCount > uint64(len(plaintext)) { + // Cap rangeCount: each range item is at least 2 varint bytes (gap + range). + if rangeCount > uint64(len(plaintext))/2 { break } malformed := false @@ -442,18 +442,18 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve fpos++ // skip frame type _, varLen := decodeQUICVarint(plaintext[fpos:]) if varLen == 0 { - return nil, fmt.Errorf("malformed CRYPTO frame offset") + return nil, fmt.Errorf("malformed crypto frame offset") } fpos += varLen // skip offset dataLen, varLen := decodeQUICVarint(plaintext[fpos:]) if varLen == 0 { - return nil, fmt.Errorf("malformed CRYPTO frame length") + return nil, fmt.Errorf("malformed crypto frame length") } fpos += varLen if dataLen > uint64(len(plaintext)-fpos) { - return nil, fmt.Errorf("CRYPTO frame data truncated") + return nil, fmt.Errorf("crypto frame data truncated") } cryptoData := plaintext[fpos : fpos+int(dataLen)] @@ -461,7 +461,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return parseServerHello(cryptoData) } - return nil, fmt.Errorf("no CRYPTO frame found in QUIC Initial response") + return nil, fmt.Errorf("no crypto frame found in QUIC Initial response") } // probeQUICCipher sends a QUIC Initial packet to the provided UDP address From d6cfe08818c55f3fc4f217185ebfb6d92162bc4c Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 15:52:26 -0500 Subject: [PATCH 23/30] docs: update CHANGELOG refs from pending to commit SHAs Co-Authored-By: Claude Opus 4.6 --- CHANGELOG.md | 50 +++++++++++++++++++++++++++----------------------- 1 file changed, 27 insertions(+), 23 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index ae1bd7a..da4fd5a 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -9,14 +9,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Added -- Add raw TLS 1.0–1.2 legacy prober for DHE/DHE-DSS cipher suites that Go's `crypto/tls` doesn't implement — probes individual suites via byte-level ClientHello construction ([`pending`]) -- Add legacy fallback to `connect` — when Go's TLS handshake fails, attempts a raw handshake to extract server certificates from DHE-only or static-RSA-only servers ([`pending`]) -- Add DHE cipher suite probing to `connect --ciphers` — detects 13 DHE/DHE-DSS cipher suites using raw ClientHello packets, all rated "weak" ([`pending`]) -- Add `dhe-kex` diagnostic to `connect --ciphers` — warns when server accepts DHE key exchange cipher suites (deprecated, vulnerable to small DH parameters) ([`pending`]) -- Add negotiated cipher diagnostics to `connect` — warns about CBC mode, 3DES, static RSA, DHE, and deprecated TLS versions even without `--ciphers` ([`pending`]) -- Add hostname-mismatch diagnostic to `connect` — detects `x509.HostnameError` and surfaces it as `[ERR] hostname-mismatch` in the diagnostics section ([`pending`]) -- Add error-level diagnostics (`verify-failed`, `ocsp-revoked`, `crl-revoked`) to `connect` output — validation failures now appear in the Diagnostics section instead of a redundant `Error:` line on stderr ([`pending`]) -- Add specific cipher diagnostics to `connect --ciphers` — replaces the single "weak cipher" message with actionable checks: `deprecated-tls10`, `deprecated-tls11`, `cbc-cipher`, `static-rsa-kex`, `3des-cipher` ([`pending`]) +- Add raw TLS 1.0–1.2 legacy prober for DHE/DHE-DSS cipher suites that Go's `crypto/tls` doesn't implement — probes individual suites via byte-level ClientHello construction ([`715cb81`]) +- Add legacy fallback to `connect` — when Go's TLS handshake fails, attempts a raw handshake to extract server certificates from DHE-only or static-RSA-only servers ([`715cb81`]) +- Add DHE cipher suite probing to `connect --ciphers` — detects 13 DHE/DHE-DSS cipher suites using raw ClientHello packets, all rated "weak" ([`715cb81`]) +- Add `dhe-kex` diagnostic to `connect --ciphers` — warns when server accepts DHE key exchange cipher suites (deprecated, vulnerable to small DH parameters) ([`715cb81`]) +- Add negotiated cipher diagnostics to `connect` — warns about CBC mode, 3DES, static RSA, DHE, and deprecated TLS versions even without `--ciphers` ([`715cb81`]) +- Add hostname-mismatch diagnostic to `connect` — detects `x509.HostnameError` and surfaces it as `[ERR] hostname-mismatch` in the diagnostics section ([`715cb81`]) +- Add error-level diagnostics (`verify-failed`, `ocsp-revoked`, `crl-revoked`) to `connect` output — validation failures now appear in the Diagnostics section instead of a redundant `Error:` line on stderr ([`715cb81`]) +- Add specific cipher diagnostics to `connect --ciphers` — replaces the single "weak cipher" message with actionable checks: `deprecated-tls10`, `deprecated-tls11`, `cbc-cipher`, `static-rsa-kex`, `3des-cipher` ([`715cb81`]) - Add `--ciphers` flag to `connect` command — enumerates all supported cipher suites with good/weak ratings, key exchange subgrouping, and forward secrecy labels ([#82]) - Add raw TLS 1.3 cipher prober — probes all 5 RFC 8446 cipher suites using byte-level ClientHello construction, no shared state or data races ([#82]) - Add key exchange group probing to `--ciphers` — detects all 7 named groups including post-quantum hybrids (X25519MLKEM768, SecP256r1MLKEM768, SecP384r1MLKEM1024) with HelloRetryRequest detection ([#82]) @@ -65,8 +65,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed -- `connect` QUIC probing no longer restricted to port 443 — QUIC can run on any UDP port ([`pending`]) -- `connect` diagnostics now distinguish `[ERR]` (verification failures) from `[WARN]` (configuration issues) ([`pending`]) +- `connect` QUIC probing no longer restricted to port 443 — QUIC can run on any UDP port ([`910b977`]) +- `connect` diagnostics now distinguish `[ERR]` (verification failures) from `[WARN]` (configuration issues) ([`910b977`]) - Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([#82]) - Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) - Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([#82]) @@ -95,14 +95,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix `OverallRating`, `FormatCipherRatingLine`, and `DiagnoseCipherScan` ignoring QUIC ciphers — weak QUIC ciphers were excluded from the overall rating and diagnostic count ([#82]) - Fix data race on `spinner.started` — replace `bool` with `atomic.Bool` for safe concurrent access (CC-3) ([#82]) - Fix bare error returns in `deriveTrafficKeys` — wrap with `%w` context per ERR-1 ([#82]) -- Fix `SupportedVersions` missing QUIC-only TLS versions — QUIC cipher versions now added to version set alongside TCP ciphers ([`pending`]) -- Fix `appendQUICVarint2` panic on values ≥ 16384 — falls back to `appendQUICVarint` instead of panicking on unexpected input ([`pending`]) -- Fix duplicate error context in `connect` CLI — `ConnectTLS` error returned directly; `ScanCipherSuites` error uses non-repeating prefix ([`pending`]) -- Fix remaining uppercase protocol names in `legacyprobe.go` error strings (ERR-4) ([`pending`]) -- Fix `readServerCertificates` totalRead check — enforce `maxCertificatePayload` limit before allocating record payload buffer, preventing over-allocation by a malicious server ([`pending`]) -- Fix QUIC ACK range count cap — use `len(plaintext)/2` instead of `len(plaintext)` since each range item requires at minimum 2 varint bytes ([`pending`]) -- Fix uppercase `CRYPTO` in `quicprobe.go` error strings — lowercase per ERR-4 ([`pending`]) -- Fix `connect` output showing misleading `Verify: OK` when result was obtained via raw legacy probe — now shows `Verify: N/A` and a `Note:` header line ([`pending`]) +- Fix `SupportedVersions` missing QUIC-only TLS versions — QUIC cipher versions now added to version set alongside TCP ciphers ([`bed32df`]) +- Fix `appendQUICVarint2` panic on values ≥ 16384 — falls back to `appendQUICVarint` instead of panicking on unexpected input ([`bed32df`]) +- Fix duplicate error context in `connect` CLI — `ConnectTLS` error returned directly; `ScanCipherSuites` error uses non-repeating prefix ([`bed32df`]) +- Fix remaining uppercase protocol names in `legacyprobe.go` error strings (ERR-4) ([`bed32df`]) +- Fix `readServerCertificates` totalRead check — enforce `maxCertificatePayload` limit before allocating record payload buffer, preventing over-allocation by a malicious server ([`900d526`]) +- Fix QUIC ACK range count cap — use `len(plaintext)/2` instead of `len(plaintext)` since each range item requires at minimum 2 varint bytes ([`900d526`]) +- Fix uppercase `CRYPTO` in `quicprobe.go` error strings — lowercase per ERR-4 ([`900d526`]) +- Fix `connect` output showing misleading `Verify: OK` when result was obtained via raw legacy probe — now shows `Verify: N/A` and a `Note:` header line ([`900d526`]) - Fix QUIC varint `uint64`→`int` overflow in `parseQUICInitialResponse` — bounds checks now compare in `uint64` space to prevent truncation on malicious packets ([#82]) - Fix ACK range loop inner `break` not propagating to outer frame parser in QUIC decoder — malformed ACK frames could corrupt subsequent frame parsing ([#82]) - Cap ACK `rangeCount` to plaintext length to prevent CPU exhaustion on malicious QUIC packets ([#82]) @@ -197,11 +197,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Replace RC4 test case with unknown cipher ID (0xFFFF) in `TestRateCipherSuite` — tests conservative rating for unrecognized ciphers ([#82]) - Remove redundant `TestFormatCipherScanResult/single_cipher` and `TestFormatCipherRatingLine/TCP_good_QUIC_weak` — subsumed by stronger cases (T-14) ([#82]) - Add `TestConnectTLS_CRL_AIAFetchedIssuer` — verifies CRL checking works when issuer is obtained via AIA walking ([#78]) -- Add `TestReadServerCertificates` cases for oversized record, unexpected content type, and ServerHelloDone-without-Certificate paths (T-8) ([`pending`]) -- Add `TestReadServerCertificates_AlertAfterServerHello` — verifies ServerHello result is preserved when alert arrives after it ([`pending`]) -- Add `TestReadServerCertificates_PayloadLimit` — verifies `maxCertificatePayload` is enforced before allocation ([`pending`]) -- Add `TestFormatConnectResult/LegacyProbe` case — verifies Note and `Verify: N/A` appear for raw-probe results ([`pending`]) -- Remove T-9 violation from `TestCipherSuiteNameLegacyIDs` — `0x1301` (TLS_AES_128_GCM_SHA256) test was exercising stdlib routing, not certkit logic ([`pending`]) +- Add `TestReadServerCertificates` cases for oversized record, unexpected content type, and ServerHelloDone-without-Certificate paths (T-8) ([`900d526`]) +- Add `TestReadServerCertificates_AlertAfterServerHello` — verifies ServerHello result is preserved when alert arrives after it ([`900d526`]) +- Add `TestReadServerCertificates_PayloadLimit` — verifies `maxCertificatePayload` is enforced before allocation ([`900d526`]) +- Add `TestFormatConnectResult/LegacyProbe` case — verifies Note and `Verify: N/A` appear for raw-probe results ([`900d526`]) +- Remove T-9 violation from `TestCipherSuiteNameLegacyIDs` — `0x1301` (TLS_AES_128_GCM_SHA256) test was exercising stdlib routing, not certkit logic ([`900d526`]) - Add `TestFetchCRL_AllowPrivateNetworks` — verifies loopback IPs succeed with `AllowPrivateNetworks` ([#78]) - Add `TestFetchCRL` unit tests for HTTP handling, redirect limits, SSRF blocking, and error paths ([#78]) - Add `TestCheckLeafCRL` table-driven tests covering revoked, good, expired CRL, wrong issuer, no CDPs, and non-HTTP CDPs ([#78]) @@ -832,6 +832,10 @@ Initial release. [0.1.2]: https://github.com/sensiblebit/certkit/compare/v0.1.1...v0.1.2 [0.1.1]: https://github.com/sensiblebit/certkit/compare/v0.1.0...v0.1.1 [0.1.0]: https://github.com/sensiblebit/certkit/releases/tag/v0.1.0 +[`900d526`]: https://github.com/sensiblebit/certkit/commit/900d526 +[`bed32df`]: https://github.com/sensiblebit/certkit/commit/bed32df +[`910b977`]: https://github.com/sensiblebit/certkit/commit/910b977 +[`715cb81`]: https://github.com/sensiblebit/certkit/commit/715cb81 [`2693116`]: https://github.com/sensiblebit/certkit/commit/2693116 [`84c4edf`]: https://github.com/sensiblebit/certkit/commit/84c4edf [`2b8cb8c`]: https://github.com/sensiblebit/certkit/commit/2b8cb8c From 6492fa52f43ad7bddd23265f54c15ccadc803d46 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 16:41:50 -0500 Subject: [PATCH 24/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20lowercase=20errors,=20naming,=20QUIC=20display,=20v?= =?UTF-8?q?ersion=20return?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - ERR-4: lowercase TLS/QUIC error strings across tls13probe.go, legacyprobe.go, quicprobe.go, and connect.go ("tls alert received", "tls record too large", "quic packet too short", "tls handshake with …") - ERR-1: wrap bare return err at CLI connect boundary with fmt.Errorf context - ERR-5: add slog.Debug before continue in QUIC ACK frame handler - Naming: rename emptyClientCert → emptyClientCertificate per convention - Bug: FormatCipherScanResult showed "none detected" for QUIC-only servers; empty check now covers both r.Ciphers and r.QUICCiphers - Bug: probeLegacyCipher hardcoded "TLS 1.2" — now returns actual negotiated version from ServerHello; ScanCipherSuites uses tlsVersionString(negotiatedVer) - T-11: remove TestBuildLegacyClientHelloMsg — behavioral coverage exists through TestLegacyFallbackConnect Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 7 ++ cmd/certkit/connect.go | 2 +- connect.go | 18 ++--- legacyprobe.go | 20 +++-- legacyprobe_test.go | 165 +---------------------------------------- quicprobe.go | 3 +- tls13probe.go | 4 +- 7 files changed, 34 insertions(+), 185 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index da4fd5a..46d5413 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -86,6 +86,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed +- Fix `connect --ciphers` showing "none detected" on QUIC-only servers — empty check now covers both TCP and QUIC cipher lists ([`pending`]) +- Fix `probeLegacyCipher` hardcoding `"TLS 1.2"` for negotiated version — now returns the actual negotiated version from the ServerHello ([`pending`]) +- Fix error strings violating ERR-4 (must be lowercase): `"tls alert received"`, `"tls record too large"`, `"quic packet too short"`, `"tls handshake with ..."` ([`pending`]) +- Fix bare `return err` at CLI connect boundary — now wraps with context per ERR-1 ([`pending`]) +- Fix missing `slog.Debug` before `continue` in QUIC ACK frame handler per ERR-5 ([`pending`]) +- Rename `emptyClientCert` → `emptyClientCertificate` per naming convention ([`pending`]) - Fix bare `return err` in `connect` CLI dropping host context from error messages — ConnectTLS and ScanCipherSuites errors now wrap with host and operation (ERR-1) ([#82]) - Fix potential out-of-bounds write in QUIC response parser when packet number length exceeds remaining packet bytes ([#82]) - Add panic guard to `appendQUICVarint2` for values >= 16384 that would silently produce corrupt 2-byte encoding ([#82]) @@ -181,6 +187,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests +- Remove `TestBuildLegacyClientHelloMsg` — behavioral coverage exists through `TestLegacyFallbackConnect` per T-11 ([`pending`]) - Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([#82]) - Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([#82]) - Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([#82]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index ef1c720..ce0c7e5 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -121,7 +121,7 @@ func runConnect(cmd *cobra.Command, args []string) error { }) if err != nil { spin.Stop() - return err + return fmt.Errorf("connecting to %s: %w", args[0], err) } // Optional cipher suite enumeration. diff --git a/connect.go b/connect.go index 8f72762..08f699c 100644 --- a/connect.go +++ b/connect.go @@ -330,7 +330,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err serverName: serverName, }) if legacyErr != nil { - return nil, fmt.Errorf("TLS handshake with %s: %w", addr, handshakeErr) + return nil, fmt.Errorf("tls handshake with %s: %w", addr, handshakeErr) } result := &ConnectResult{ Host: input.Host, @@ -1025,16 +1025,16 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher probeCtx, probeCancel := context.WithTimeout(ctx, probeTimeout) defer probeCancel() - if probeLegacyCipher(probeCtx, cipherProbeInput{ + if negotiatedVer, ok := probeLegacyCipher(probeCtx, cipherProbeInput{ addr: addr, serverName: serverName, cipherID: d.ID, version: tls.VersionTLS12, - }) { + }); ok { r := CipherProbeResult{ Name: d.Name, ID: d.ID, - Version: "TLS 1.2", + Version: tlsVersionString(negotiatedVer), KeyExchange: d.KeyExchange, Rating: CipherRatingWeak, } @@ -1208,10 +1208,10 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher }, nil } -// emptyClientCert is a GetClientCertificate callback that returns an empty +// emptyClientCertificate is a GetClientCertificate callback that returns an empty // certificate. This is needed so the handshake progresses far enough to // negotiate a cipher suite even when the server requests client auth (mTLS). -func emptyClientCert(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) { +func emptyClientCertificate(_ *tls.CertificateRequestInfo) (*tls.Certificate, error) { return &tls.Certificate{}, nil } @@ -1230,7 +1230,7 @@ func probeCipher(ctx context.Context, input cipherProbeInput) bool { MinVersion: input.version, MaxVersion: input.version, CipherSuites: []uint16{input.cipherID}, - GetClientCertificate: emptyClientCert, + GetClientCertificate: emptyClientCertificate, }) defer func() { _ = tlsConn.Close() }() @@ -1276,7 +1276,7 @@ func probeKeyExchangeGroupLegacy(ctx context.Context, input cipherProbeInput) bo MaxVersion: tls.VersionTLS12, CipherSuites: ecdheOnlyCipherSuites, CurvePreferences: []tls.CurveID{input.groupID}, - GetClientCertificate: emptyClientCert, + GetClientCertificate: emptyClientCertificate, }) defer func() { _ = tlsConn.Close() }() @@ -1469,7 +1469,7 @@ func FormatCipherScanResult(r *CipherScanResult) string { if r == nil { return "" } - if len(r.Ciphers) == 0 { + if len(r.Ciphers) == 0 && len(r.QUICCiphers) == 0 { return "\nCipher suites: none detected\n" } diff --git a/legacyprobe.go b/legacyprobe.go index 206922a..3037c13 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -119,12 +119,13 @@ func appendECPointFormatsExtension(b []byte) []byte { } // probeLegacyCipher attempts a raw TLS 1.0–1.2 ClientHello with a single -// legacy cipher suite and returns true if the server accepts it. -func probeLegacyCipher(ctx context.Context, input cipherProbeInput) bool { +// legacy cipher suite. It returns the negotiated TLS version and true if the +// server accepts the cipher suite; returns 0, false on any failure or rejection. +func probeLegacyCipher(ctx context.Context, input cipherProbeInput) (uint16, bool) { dialer := &net.Dialer{} conn, err := dialer.DialContext(ctx, "tcp", input.addr) if err != nil { - return false + return 0, false } defer func() { _ = conn.Close() }() @@ -137,19 +138,22 @@ func probeLegacyCipher(ctx context.Context, input cipherProbeInput) bool { cipherSuites: []uint16{input.cipherID}, }) if err != nil { - return false + return 0, false } if _, err := conn.Write(wrapTLSRecord(msg)); err != nil { - return false + return 0, false } result, err := readServerHello(conn) if err != nil { - return false + return 0, false } - return result.version <= tls.VersionTLS12 && result.cipherSuite == input.cipherID + if result.version <= tls.VersionTLS12 && result.cipherSuite == input.cipherID { + return result.version, true + } + return 0, false } // maxCertificatePayload is the maximum total bytes we'll read from the server @@ -187,7 +191,7 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat recordLen := int(binary.BigEndian.Uint16(header[3:5])) if recordLen > 16640 { - return shResult, certs, fmt.Errorf("TLS record too large: %d bytes", recordLen) + return shResult, certs, fmt.Errorf("tls record too large: %d bytes", recordLen) } // Check before allocating: a malicious server cannot force us to allocate // more than maxCertificatePayload bytes even if record sizes are valid. diff --git a/legacyprobe_test.go b/legacyprobe_test.go index e5d1916..7f9e857 100644 --- a/legacyprobe_test.go +++ b/legacyprobe_test.go @@ -7,7 +7,6 @@ import ( "crypto/rand" "crypto/x509" "crypto/x509/pkix" - "encoding/binary" "errors" "math/big" "net" @@ -16,168 +15,6 @@ import ( "time" ) -func TestBuildLegacyClientHelloMsg(t *testing.T) { - t.Parallel() - - tests := []struct { - name string - input legacyClientHelloInput - wantErr bool - }{ - { - name: "single cipher suite with SNI", - input: legacyClientHelloInput{ - serverName: "example.com", - cipherSuites: []uint16{0x0033}, - }, - }, - { - name: "multiple cipher suites", - input: legacyClientHelloInput{ - serverName: "test.example.com", - cipherSuites: []uint16{0x0033, 0x0039, 0x009E}, - }, - }, - { - name: "no server name", - input: legacyClientHelloInput{ - cipherSuites: []uint16{0x0033}, - }, - }, - { - name: "no cipher suites", - input: legacyClientHelloInput{ - serverName: "example.com", - }, - wantErr: true, - }, - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - t.Parallel() - msg, err := buildLegacyClientHelloMsg(tt.input) - if tt.wantErr { - if err == nil { - t.Fatal("expected error, got nil") - } - return - } - if err != nil { - t.Fatalf("unexpected error: %v", err) - } - - // Verify it's a valid handshake message. - if len(msg) < 4 { - t.Fatalf("message too short: %d bytes", len(msg)) - } - if msg[0] != 0x01 { - t.Errorf("handshake type = 0x%02x, want 0x01 (ClientHello)", msg[0]) - } - - // Parse handshake length. - hsLen := int(msg[1])<<16 | int(msg[2])<<8 | int(msg[3]) - if len(msg) != 4+hsLen { - t.Fatalf("handshake length mismatch: header says %d, actual body is %d", hsLen, len(msg)-4) - } - - body := msg[4:] - - // Legacy version should be TLS 1.2 (0x0303). - if body[0] != 0x03 || body[1] != 0x03 { - t.Errorf("legacy version = 0x%02x%02x, want 0x0303 (TLS 1.2)", body[0], body[1]) - } - - // Client random: 32 bytes at offset 2. - pos := 2 + 32 - - // Session ID: should be empty (length 0). - sessionIDLen := int(body[pos]) - pos++ - if sessionIDLen != 0 { - t.Errorf("session ID length = %d, want 0", sessionIDLen) - } - pos += sessionIDLen - - // Cipher suites length. - csLen := int(binary.BigEndian.Uint16(body[pos : pos+2])) - pos += 2 - wantCSLen := len(tt.input.cipherSuites) * 2 - if csLen != wantCSLen { - t.Errorf("cipher suites length = %d, want %d", csLen, wantCSLen) - } - - // Verify cipher suite values. - for i, wantCS := range tt.input.cipherSuites { - gotCS := binary.BigEndian.Uint16(body[pos+i*2 : pos+i*2+2]) - if gotCS != wantCS { - t.Errorf("cipher suite[%d] = 0x%04x, want 0x%04x", i, gotCS, wantCS) - } - } - pos += csLen - - // Compression methods: 1 byte length, 1 byte null. - if body[pos] != 1 || body[pos+1] != 0 { - t.Errorf("compression = [%d, %d], want [1, 0]", body[pos], body[pos+1]) - } - pos += 2 - - // Extensions. - if pos+2 > len(body) { - t.Fatal("body truncated at extensions length") - } - extLen := int(binary.BigEndian.Uint16(body[pos : pos+2])) - pos += 2 - if pos+extLen != len(body) { - t.Fatalf("extensions length mismatch: says %d, remaining is %d", extLen, len(body)-pos) - } - - // Parse extensions and check for expected/unexpected types. - extData := body[pos:] - foundSNI := false - foundSigAlg := false - foundECPointFormats := false - for len(extData) >= 4 { - extType := binary.BigEndian.Uint16(extData[0:2]) - extDataLen := int(binary.BigEndian.Uint16(extData[2:4])) - if 4+extDataLen > len(extData) { - t.Fatalf("extension truncated: type 0x%04x, length %d", extType, extDataLen) - } - - switch extType { - case 0x0000: - foundSNI = true - case 0x000d: - foundSigAlg = true - case 0x000b: - foundECPointFormats = true - case 0x002b: // supported_versions — TLS 1.3 only - t.Error("found supported_versions extension (0x002b) — should not be in legacy ClientHello") - case 0x0033: // key_share — TLS 1.3 only - t.Error("found key_share extension (0x0033) — should not be in legacy ClientHello") - case 0x002d: // psk_key_exchange_modes — TLS 1.3 only - t.Error("found psk_key_exchange_modes extension (0x002d) — should not be in legacy ClientHello") - } - - extData = extData[4+extDataLen:] - } - - if tt.input.serverName != "" && !foundSNI { - t.Error("SNI extension not found") - } - if tt.input.serverName == "" && foundSNI { - t.Error("SNI extension present but no server name specified") - } - if !foundSigAlg { - t.Error("signature_algorithms extension not found") - } - if !foundECPointFormats { - t.Error("ec_point_formats extension not found") - } - }) - } -} - func TestParseCertificateMessage(t *testing.T) { t.Parallel() @@ -345,7 +182,7 @@ func TestReadServerCertificates(t *testing.T) { { name: "oversized TLS record", records: buildRawTLSRecord(0x16, 16641), - wantErrContains: "TLS record too large", + wantErrContains: "tls record too large", }, { name: "unexpected content type", diff --git a/quicprobe.go b/quicprobe.go index de9035e..9ff9b98 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -220,7 +220,7 @@ func buildQUICInitialPacket(input quicInitialPacketInput) ([]byte, error) { // extracts the ServerHello from the CRYPTO frame. func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serverHelloResult, error) { if len(packet) < 5 { - return nil, fmt.Errorf("QUIC packet too short: %d bytes", len(packet)) + return nil, fmt.Errorf("quic packet too short: %d bytes", len(packet)) } // Check it's a Long Header Initial packet. @@ -431,6 +431,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve break } } + slog.Debug("skipping QUIC ACK frame") continue } if frameType != 0x06 { diff --git a/tls13probe.go b/tls13probe.go index 6e388f3..a9e7309 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -61,7 +61,7 @@ type serverHelloResult struct { // errAlertReceived is returned when the server responds with a TLS Alert // instead of a ServerHello, indicating the cipher suite or group was rejected. -var errAlertReceived = errors.New("TLS alert received") +var errAlertReceived = errors.New("tls alert received") // errHelloRetryRequest is returned when the server responds with a // HelloRetryRequest instead of a real ServerHello. Per RFC 8446 §4.1.3, an HRR @@ -257,7 +257,7 @@ func readServerHello(r io.Reader) (*serverHelloResult, error) { // TLS records are limited to 16384 bytes plus some overhead. if recordLen > 16640 { - return nil, fmt.Errorf("TLS record too large: %d bytes", recordLen) + return nil, fmt.Errorf("tls record too large: %d bytes", recordLen) } payload := make([]byte, recordLen) From df5511b39c9863bf5be7e5344db81a769695ffec Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 16:43:48 -0500 Subject: [PATCH 25/30] docs: update changelog pending refs to 6492fa5 Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 46d5413..6ea165c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -86,12 +86,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Fix `connect --ciphers` showing "none detected" on QUIC-only servers — empty check now covers both TCP and QUIC cipher lists ([`pending`]) -- Fix `probeLegacyCipher` hardcoding `"TLS 1.2"` for negotiated version — now returns the actual negotiated version from the ServerHello ([`pending`]) -- Fix error strings violating ERR-4 (must be lowercase): `"tls alert received"`, `"tls record too large"`, `"quic packet too short"`, `"tls handshake with ..."` ([`pending`]) -- Fix bare `return err` at CLI connect boundary — now wraps with context per ERR-1 ([`pending`]) -- Fix missing `slog.Debug` before `continue` in QUIC ACK frame handler per ERR-5 ([`pending`]) -- Rename `emptyClientCert` → `emptyClientCertificate` per naming convention ([`pending`]) +- Fix `connect --ciphers` showing "none detected" on QUIC-only servers — empty check now covers both TCP and QUIC cipher lists ([`6492fa5`]) +- Fix `probeLegacyCipher` hardcoding `"TLS 1.2"` for negotiated version — now returns the actual negotiated version from the ServerHello ([`6492fa5`]) +- Fix error strings violating ERR-4 (must be lowercase): `"tls alert received"`, `"tls record too large"`, `"quic packet too short"`, `"tls handshake with ..."` ([`6492fa5`]) +- Fix bare `return err` at CLI connect boundary — now wraps with context per ERR-1 ([`6492fa5`]) +- Fix missing `slog.Debug` before `continue` in QUIC ACK frame handler per ERR-5 ([`6492fa5`]) +- Rename `emptyClientCert` → `emptyClientCertificate` per naming convention ([`6492fa5`]) - Fix bare `return err` in `connect` CLI dropping host context from error messages — ConnectTLS and ScanCipherSuites errors now wrap with host and operation (ERR-1) ([#82]) - Fix potential out-of-bounds write in QUIC response parser when packet number length exceeds remaining packet bytes ([#82]) - Add panic guard to `appendQUICVarint2` for values >= 16384 that would silently produce corrupt 2-byte encoding ([#82]) @@ -187,7 +187,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests -- Remove `TestBuildLegacyClientHelloMsg` — behavioral coverage exists through `TestLegacyFallbackConnect` per T-11 ([`pending`]) +- Remove `TestBuildLegacyClientHelloMsg` — behavioral coverage exists through `TestLegacyFallbackConnect` per T-11 ([`6492fa5`]) - Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([#82]) - Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([#82]) - Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([#82]) @@ -924,3 +924,4 @@ Initial release. [#25]: https://github.com/sensiblebit/certkit/pull/25 [#26]: https://github.com/sensiblebit/certkit/pull/26 [#27]: https://github.com/sensiblebit/certkit/pull/27 +[`6492fa5`]: https://github.com/sensiblebit/certkit/commit/6492fa52f43ad7bddd23265f54c15ccadc803d46 From 772742c20a59cc89ce44889c7b6cde5756ad6ae2 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 16:51:27 -0500 Subject: [PATCH 26/30] =?UTF-8?q?fix:=20show=20real=20verify=20result=20fo?= =?UTF-8?q?r=20legacy=20probe=20=E2=80=94=20chain=20is=20verified,=20key?= =?UTF-8?q?=20possession=20is=20not?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The raw legacy probe path calls populateConnectResult which runs full x509.Verify against the system root store, AIA walking, OCSP, and CRL checks. The old "Verify: N/A (raw handshake — certificate not cryptographically verified)" message was misleading — the chain IS cryptographically verified. What is NOT verified is that the server possesses the private key for the certificate (no TLS Finished message was exchanged). Update: remove the LegacyProbe branch that suppressed Verify output; show the real result (OK/FAILED). Update the Note line and the legacy-only diagnostic to accurately describe what is and isn't verified. Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 1 + cmd/certkit/connect.go | 6 ++---- connect.go | 8 +++----- connect_test.go | 14 +++++++------- 4 files changed, 13 insertions(+), 16 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 6ea165c..be9e34d 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -86,6 +86,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed +- Fix `connect` legacy probe showing `Verify: N/A` despite performing full x509 chain verification — now shows the real verify result (`OK`/`FAILED`); Note line updated to clarify only server key possession is unverified ([`pending`]) - Fix `connect --ciphers` showing "none detected" on QUIC-only servers — empty check now covers both TCP and QUIC cipher lists ([`6492fa5`]) - Fix `probeLegacyCipher` hardcoding `"TLS 1.2"` for negotiated version — now returns the actual negotiated version from the ServerHello ([`6492fa5`]) - Fix error strings violating ERR-4 (must be lowercase): `"tls alert received"`, `"tls record too large"`, `"quic packet too short"`, `"tls handshake with ..."` ([`6492fa5`]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index ce0c7e5..74598d3 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -286,16 +286,14 @@ func formatConnectVerbose(r *certkit.ConnectResult, now time.Time) string { fmt.Fprintf(&out, "Server Name: %s\n", r.ServerName) if r.LegacyProbe { - out.WriteString("Note: certificate obtained via raw probe — server only supports legacy cipher suites\n") + out.WriteString("Note: certificate obtained via raw probe — server key possession not verified\n") } if r.ALPN != "" { fmt.Fprintf(&out, "ALPN: %s\n", r.ALPN) } - if r.LegacyProbe { - out.WriteString("Verify: N/A (raw handshake — certificate not cryptographically verified)\n") - } else if r.VerifyError != "" { + if r.VerifyError != "" { fmt.Fprintf(&out, "Verify: FAILED (%s)\n", r.VerifyError) } else if r.AIAFetched { out.WriteString("Verify: OK (intermediates fetched via AIA)\n") diff --git a/connect.go b/connect.go index 08f699c..49a5137 100644 --- a/connect.go +++ b/connect.go @@ -345,7 +345,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err result.Diagnostics = append(result.Diagnostics, ChainDiagnostic{ Check: "legacy-only", Status: "warn", - Detail: "server only supports cipher suites not available in standard TLS libraries — connected via raw handshake", + Detail: "server only supports cipher suites not available in standard TLS libraries; certificate chain verified but server key possession not proven", }) return result, nil } @@ -1527,16 +1527,14 @@ func FormatConnectResult(r *ConnectResult) string { fmt.Fprintf(&out, "Server Name: %s\n", r.ServerName) if r.LegacyProbe { - out.WriteString("Note: certificate obtained via raw probe — server only supports legacy cipher suites\n") + out.WriteString("Note: certificate obtained via raw probe — server key possession not verified\n") } if r.ALPN != "" { fmt.Fprintf(&out, "ALPN: %s\n", r.ALPN) } - if r.LegacyProbe { - out.WriteString("Verify: N/A (raw handshake — certificate not cryptographically verified)\n") - } else if r.VerifyError != "" { + if r.VerifyError != "" { fmt.Fprintf(&out, "Verify: FAILED (%s)\n", r.VerifyError) } else if r.AIAFetched { out.WriteString("Verify: OK (intermediates fetched via AIA)\n") diff --git a/connect_test.go b/connect_test.go index 75c25fd..5cd11cc 100644 --- a/connect_test.go +++ b/connect_test.go @@ -420,8 +420,8 @@ func TestFormatConnectResult(t *testing.T) { }, } - // LegacyProbe cases are structurally different: the result has LegacyProbe=true. - t.Run("LegacyProbe shows Note and Verify N/A", func(t *testing.T) { + // LegacyProbe: Note shows key-possession caveat; Verify shows real chain result. + t.Run("LegacyProbe shows Note and real Verify result", func(t *testing.T) { t.Parallel() result := &ConnectResult{ Host: "test.example.com", @@ -436,16 +436,16 @@ func TestFormatConnectResult(t *testing.T) { for _, want := range []string{ "Note:", "raw probe", - "Verify: N/A", - "not cryptographically verified", + "server key possession not verified", + "Verify: OK", } { if !strings.Contains(output, want) { t.Errorf("output missing %q\ngot:\n%s", want, output) } } - // Must NOT show "Verify: OK" for a legacy probe result. - if strings.Contains(output, "Verify: OK") { - t.Errorf("output contains misleading %q for LegacyProbe result\ngot:\n%s", "Verify: OK", output) + // Must NOT show the old "N/A" placeholder. + if strings.Contains(output, "N/A") { + t.Errorf("output contains stale N/A placeholder\ngot:\n%s", output) } }) From d4a402f8305f006146c8800dc39c7e50c0697e44 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 16:51:50 -0500 Subject: [PATCH 27/30] docs: update changelog pending ref to 772742c Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index be9e34d..04fe0b4 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -86,7 +86,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Fixed -- Fix `connect` legacy probe showing `Verify: N/A` despite performing full x509 chain verification — now shows the real verify result (`OK`/`FAILED`); Note line updated to clarify only server key possession is unverified ([`pending`]) +- Fix `connect` legacy probe showing `Verify: N/A` despite performing full x509 chain verification — now shows the real verify result (`OK`/`FAILED`); Note line updated to clarify only server key possession is unverified ([`772742c`]) - Fix `connect --ciphers` showing "none detected" on QUIC-only servers — empty check now covers both TCP and QUIC cipher lists ([`6492fa5`]) - Fix `probeLegacyCipher` hardcoding `"TLS 1.2"` for negotiated version — now returns the actual negotiated version from the ServerHello ([`6492fa5`]) - Fix error strings violating ERR-4 (must be lowercase): `"tls alert received"`, `"tls record too large"`, `"quic packet too short"`, `"tls handshake with ..."` ([`6492fa5`]) @@ -926,3 +926,4 @@ Initial release. [#26]: https://github.com/sensiblebit/certkit/pull/26 [#27]: https://github.com/sensiblebit/certkit/pull/27 [`6492fa5`]: https://github.com/sensiblebit/certkit/commit/6492fa52f43ad7bddd23265f54c15ccadc803d46 +[`772742c`]: https://github.com/sensiblebit/certkit/commit/772742c20a59cc89ce44889c7b6cde5756ad6ae2 From ef4c458134ff0f8b695ee1b9aa80c528cdc93b42 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 18:25:22 -0500 Subject: [PATCH 28/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20legacy=20probe=20OCSP,=20TLS=20alert=20guard,=20QUI?= =?UTF-8?q?C=20port?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Skip OCSP and CRL checks for legacy probes; revocation is not meaningful without an authenticated TLS channel. Eliminates misleading "OCSP: skipped (no issuer in chain)" output on raw handshake results. x509 chain verification is still performed. - Guard legacy fallback behind tls.AlertError: only attempt raw DHE probe when the server sent a TLS alert (cipher negotiation failure), not for network errors or certificate errors that would add a spurious 5-second timeout. - Restrict QUIC probing to port 443: non-443 ports cause spurious timeouts since QUIC is not conventionally served there. - Fix TOCTOU in spinner.Stop(): remove started guard, use stopOnce unconditionally — works correctly whether Stop() races with Start() or not. - Replace in-place diagnostics filter with a new slice allocation to eliminate aliasing confusion. - Remove stale CHANGELOG entry saying QUIC is unrestricted (reversed). Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 6 ++++-- cmd/certkit/connect.go | 2 +- cmd/certkit/spinner.go | 7 ------- connect.go | 27 +++++++++++++++++++++++---- 4 files changed, 28 insertions(+), 14 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 04fe0b4..efa9c5c 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -65,7 +65,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Changed -- `connect` QUIC probing no longer restricted to port 443 — QUIC can run on any UDP port ([`910b977`]) - `connect` diagnostics now distinguish `[ERR]` (verification failures) from `[WARN]` (configuration issues) ([`910b977`]) - Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([#82]) - Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) @@ -100,7 +99,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Use `slices.Concat` instead of `append` for cipher suite slice concatenation — prevents potential mutation of stdlib return value ([#82]) - Show "Cipher suites: none detected" when cipher scan finds no supported suites instead of silent empty output ([#82]) - Fix `OverallRating`, `FormatCipherRatingLine`, and `DiagnoseCipherScan` ignoring QUIC ciphers — weak QUIC ciphers were excluded from the overall rating and diagnostic count ([#82]) -- Fix data race on `spinner.started` — replace `bool` with `atomic.Bool` for safe concurrent access (CC-3) ([#82]) +- Fix TOCTOU race in `spinner.Stop()` — remove started guard and use `stopOnce` unconditionally so Stop() is safe regardless of concurrency with Start() ([#82]) +- Fix `connect` legacy probe running OCSP and CRL checks — revocation checks are now skipped for legacy probes since there is no cryptographic chain to verify revocation against; eliminates misleading `OCSP: skipped (no issuer certificate in chain)` output ([#82]) +- Fix `connect` legacy fallback triggering on all TLS handshake failures — now only attempted on `tls.AlertError` (cipher negotiation failure), not network errors or certificate errors that would add a spurious 5-second timeout ([#82]) +- Fix `connect --ciphers` diagnostics filter using in-place slice aliasing — now allocates a new slice to avoid confusing aliasing semantics ([#82]) - Fix bare error returns in `deriveTrafficKeys` — wrap with `%w` context per ERR-1 ([#82]) - Fix `SupportedVersions` missing QUIC-only TLS versions — QUIC cipher versions now added to version set alongside TCP ciphers ([`bed32df`]) - Fix `appendQUICVarint2` panic on values ≥ 16384 — falls back to `appendQUICVarint` instead of panicking on unexpected input ([`bed32df`]) diff --git a/cmd/certkit/connect.go b/cmd/certkit/connect.go index 74598d3..2385d13 100644 --- a/cmd/certkit/connect.go +++ b/cmd/certkit/connect.go @@ -149,7 +149,7 @@ func runConnect(cmd *cobra.Command, args []string) error { for _, d := range scanDiags { scanChecks[d.Check] = true } - filtered := result.Diagnostics[:0] + var filtered []certkit.ChainDiagnostic for _, d := range result.Diagnostics { if !scanChecks[d.Check] { filtered = append(filtered, d) diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go index bce3d8a..3243071 100644 --- a/cmd/certkit/spinner.go +++ b/cmd/certkit/spinner.go @@ -5,7 +5,6 @@ import ( "fmt" "os" "sync" - "sync/atomic" "time" "github.com/mattn/go-isatty" @@ -20,7 +19,6 @@ type spinner struct { done chan struct{} startOnce sync.Once stopOnce sync.Once - started atomic.Bool } // newSpinner creates a spinner with the given message. Call Start() to begin @@ -44,7 +42,6 @@ func (s *spinner) Start(ctx context.Context) { return } - s.started.Store(true) go s.run(ctx) }) } @@ -58,10 +55,6 @@ func (s *spinner) SetMessage(msg string) { // Stop halts the spinner and clears the line. Safe to call multiple times. func (s *spinner) Stop() { - if !s.started.Load() { - <-s.done - return - } s.stopOnce.Do(func() { close(s.stop) }) <-s.done } diff --git a/connect.go b/connect.go index 49a5137..2dfc080 100644 --- a/connect.go +++ b/connect.go @@ -315,12 +315,15 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err } handshakeErr := tlsConn.HandshakeContext(ctx) - if handshakeErr != nil && clientAuth == nil { + var tlsAlert tls.AlertError + if handshakeErr != nil && clientAuth == nil && errors.As(handshakeErr, &tlsAlert) { // Close the failed TLS connection before opening a new one. // The deferred tlsConn.Close() will be a no-op after this. _ = tlsConn.Close() // Try raw legacy handshake to detect DHE/static-RSA-only servers. + // Only attempt this when the server sent a TLS alert (cipher + // negotiation failure), not for network errors or certificate errors. // Use a dedicated timeout so a stalling server can't hold the // fallback connection open indefinitely. fallbackCtx, fallbackCancel := context.WithTimeout(ctx, 5*time.Second) @@ -348,6 +351,11 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err Detail: "server only supports cipher suites not available in standard TLS libraries; certificate chain verified but server key possession not proven", }) return result, nil + } else if handshakeErr != nil && clientAuth == nil { + // Non-alert failure (network error, certificate error, etc.) — return + // immediately. The mTLS fallback path below is only for client auth + // rejection, which only occurs when clientAuth is non-nil. + return nil, fmt.Errorf("tls handshake with %s: %w", addr, handshakeErr) } // When the server requested a client cert and rejected our empty @@ -438,6 +446,15 @@ func populateConnectResult(ctx context.Context, result *ConnectResult, input Con return } + // For legacy probes, certificate chain verification has been run above and + // the result is included in the output. However, OCSP and CRL revocation + // checks require a verified issuer from a real TLS channel — skipping + // them prevents misleading "skipped (no issuer in chain)" OCSP output + // when the legacy handshake produced an untrusted certificate. + if result.LegacyProbe { + return + } + // Resolve the issuer certificate for revocation checks. // Only use VerifiedChains (cryptographically validated). Do not fall back // to PeerCertificates — those are raw, unverified certs from the server and @@ -1091,9 +1108,11 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher }(gid) } - // Probe QUIC/UDP cipher suites if requested. + // Probe QUIC/UDP cipher suites if requested and the target port is 443. + // QUIC is only meaningful on UDP 443; probing arbitrary ports produces + // spurious timeouts on servers that don't run QUIC. var quicCiphers []CipherProbeResult - if input.ProbeQUIC { + if input.ProbeQUIC && port == "443" { quicAddr := net.JoinHostPort(input.Host, port) for _, id := range tls13CipherSuites { if ctx.Err() != nil { @@ -1201,7 +1220,7 @@ func ScanCipherSuites(ctx context.Context, input ScanCipherSuitesInput) (*Cipher return &CipherScanResult{ SupportedVersions: versions, Ciphers: results, - QUICProbed: input.ProbeQUIC, + QUICProbed: input.ProbeQUIC && port == "443", QUICCiphers: quicCiphers, KeyExchanges: keyExchanges, OverallRating: overall, From 264281e0ed6acc6d8c2e40ee8845fb8d52390897 Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 18:34:53 -0500 Subject: [PATCH 29/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20CS-5,=20T-11,=20CL-4?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Convert populateConnectResult to (*ConnectResult).populate — reduces argument count from 3 to 2 (ctx + input) per CS-5 - Remove TestParseCertificateMessage — behavioral coverage exists through TestReadServerCertificates (T-11) - Remove TestCipherSuiteNameLegacyIDs — behavioral coverage exists through TestScanCipherSuites (T-11) - Shorten full-SHA CHANGELOG link definitions to 7-char SHAs (CL-4) Co-Authored-By: Claude Sonnet 4.6 --- CHANGELOG.md | 7 +++- connect.go | 12 +++--- legacyprobe_test.go | 95 --------------------------------------------- 3 files changed, 11 insertions(+), 103 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index efa9c5c..0fb74ce 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -69,6 +69,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Harden QUIC response parser — add bounds checks for DCID/SCID lengths, varint decode guards to prevent infinite loops on malformed ACK frames, and increase UDP read buffer to 65535 bytes ([#82]) - Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) - Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([#82]) +- Convert `populateConnectResult` to a method `(*ConnectResult).populate` per CS-5 — reduces argument count from 3 to 2 (ctx + input) ([#82]) - **Breaking:** Rename `csr --cert` flag to `--from-cert` for clarity — avoids confusion with certificate file arguments in other commands ([#80]) - **Breaking:** `connect` JSON `sha256_fingerprint` format changed from lowercase hex to colon-separated uppercase hex for CLI-4 consistency with `inspect` and `sha1_fingerprint` ([#80]) - **Breaking:** Rename `CRLCheckResult.DistributionPoint` to `CRLCheckResult.URL` (JSON: `url`) and `OCSPResult.ResponderURL` to `OCSPResult.URL` (JSON: `url`) — consistent field name for the checked endpoint across both revocation types (CLI-4) ([#78]) @@ -191,6 +192,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 ### Tests - Remove `TestBuildLegacyClientHelloMsg` — behavioral coverage exists through `TestLegacyFallbackConnect` per T-11 ([`6492fa5`]) +- Remove `TestParseCertificateMessage` — behavioral coverage exists through `TestReadServerCertificates` per T-11 ([#82]) +- Remove `TestCipherSuiteNameLegacyIDs` — behavioral coverage exists through `TestScanCipherSuites` per T-11 ([#82]) - Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([#82]) - Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([#82]) - Merge `TestScanCipherSuites_KeyExchanges` into `TestScanCipherSuites` — eliminates redundant server setup (T-14) ([#82]) @@ -927,5 +930,5 @@ Initial release. [#25]: https://github.com/sensiblebit/certkit/pull/25 [#26]: https://github.com/sensiblebit/certkit/pull/26 [#27]: https://github.com/sensiblebit/certkit/pull/27 -[`6492fa5`]: https://github.com/sensiblebit/certkit/commit/6492fa52f43ad7bddd23265f54c15ccadc803d46 -[`772742c`]: https://github.com/sensiblebit/certkit/commit/772742c20a59cc89ce44889c7b6cde5756ad6ae2 +[`6492fa5`]: https://github.com/sensiblebit/certkit/commit/6492fa5 +[`772742c`]: https://github.com/sensiblebit/certkit/commit/772742c diff --git a/connect.go b/connect.go index 2dfc080..a11760b 100644 --- a/connect.go +++ b/connect.go @@ -344,7 +344,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err PeerChain: legacyResult.certificates, LegacyProbe: true, } - populateConnectResult(ctx, result, input) + result.populate(ctx, input) result.Diagnostics = append(result.Diagnostics, ChainDiagnostic{ Check: "legacy-only", Status: "warn", @@ -375,14 +375,14 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err PeerChain: state.PeerCertificates, } - populateConnectResult(ctx, result, input) + result.populate(ctx, input) return result, nil } -// populateConnectResult runs chain diagnostics, verification, OCSP, and CRL -// checks on a ConnectResult. It is shared between the normal handshake path -// and the legacy fallback path. -func populateConnectResult(ctx context.Context, result *ConnectResult, input ConnectTLSInput) { +// populate runs chain diagnostics, verification, OCSP, and CRL checks on the +// ConnectResult. It is shared between the normal handshake path and the legacy +// fallback path. +func (result *ConnectResult) populate(ctx context.Context, input ConnectTLSInput) { serverName := result.ServerName // Diagnose the negotiated cipher suite and protocol version. diff --git a/legacyprobe_test.go b/legacyprobe_test.go index 7f9e857..d05e272 100644 --- a/legacyprobe_test.go +++ b/legacyprobe_test.go @@ -15,78 +15,6 @@ import ( "time" ) -func TestParseCertificateMessage(t *testing.T) { - t.Parallel() - - // Generate a test certificate. - key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader) - if err != nil { - t.Fatal(err) - } - template := &x509.Certificate{ - SerialNumber: big.NewInt(1), - Subject: pkix.Name{CommonName: "test"}, - NotBefore: time.Now().Add(-time.Hour), - NotAfter: time.Now().Add(time.Hour), - } - certDER, err := x509.CreateCertificate(rand.Reader, template, template, &key.PublicKey, key) - if err != nil { - t.Fatal(err) - } - - tests := []struct { - name string - data []byte - wantCerts int - wantErr bool - }{ - { - name: "single certificate", - data: buildCertificateMessageBody(certDER), - wantCerts: 1, - }, - { - name: "two certificates", - data: buildCertificateMessageBody(certDER, certDER), - wantCerts: 2, - }, - { - name: "empty certificate list", - data: []byte{0, 0, 0}, // total_len = 0 - wantCerts: 0, - }, - { - name: "truncated header", - data: []byte{0, 0}, - wantErr: true, - }, - { - name: "truncated certificate entry", - data: []byte{0, 0, 10, 0, 0, 5, 1, 2, 3}, // claims 5 bytes but only 3 - wantErr: true, - }, - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - t.Parallel() - certs, err := parseCertificateMessage(tt.data) - if tt.wantErr { - if err == nil { - t.Fatal("expected error, got nil") - } - return - } - if err != nil { - t.Fatalf("unexpected error: %v", err) - } - if len(certs) != tt.wantCerts { - t.Errorf("got %d certificates, want %d", len(certs), tt.wantCerts) - } - }) - } -} - // buildCertificateMessageBody constructs a TLS Certificate message body // from DER-encoded certificates. func buildCertificateMessageBody(certs ...[]byte) []byte { @@ -408,26 +336,3 @@ func TestLegacyFallbackConnect(t *testing.T) { t.Errorf("cert CN = %q, want %q", result.certificates[0].Subject.CommonName, leafCert.Subject.CommonName) } } - -func TestCipherSuiteNameLegacyIDs(t *testing.T) { - t.Parallel() - - tests := []struct { - id uint16 - want string - }{ - {0x0033, "TLS_DHE_RSA_WITH_AES_128_CBC_SHA"}, - {0x009E, "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256"}, - {0x0032, "TLS_DHE_DSS_WITH_AES_128_CBC_SHA"}, - } - - for _, tt := range tests { - t.Run(tt.want, func(t *testing.T) { - t.Parallel() - got := cipherSuiteName(tt.id) - if got != tt.want { - t.Errorf("cipherSuiteName(0x%04x) = %q, want %q", tt.id, got, tt.want) - } - }) - } -} From 0c24518d10590e91e5384bc61ce97dc518a1f86b Mon Sep 17 00:00:00 2001 From: Daniel Wood Date: Fri, 27 Feb 2026 19:29:07 -0500 Subject: [PATCH 30/30] =?UTF-8?q?fix:=20address=20review=20findings=20?= =?UTF-8?q?=E2=80=94=20Stop=20deadlock,=20ERR-4/5,=20CS-5,=20error=20conte?= =?UTF-8?q?xt?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit - Fix Stop() deadlock when called before Start(): use startOnce.Do to close done channel, ensuring <-s.done never blocks regardless of call order - Include legacyErr in error message when TLS handshake + fallback both fail - Update RateCipherSuite comment: clarify DHE/DSS have no modern FS guarantees - Lowercase QUIC/TLS error strings in quicprobe.go, legacyprobe.go, tls13probe.go per ERR-4 (error strings must be lowercase, acronyms included) - Extract appendKeyShareExtensionInput struct for appendKeyShareExtension per CS-5 - Fix ERR-5 in TestLegacyFallbackConnect: log Read/Write errors via slog.Debug - Update test assertion for lowercased error string --- CHANGELOG.md | 5 +++++ cmd/certkit/spinner.go | 5 ++++- connect.go | 4 ++-- legacyprobe.go | 8 ++++---- legacyprobe_test.go | 11 ++++++++--- quicprobe.go | 6 +++--- tls13probe.go | 32 +++++++++++++++++++------------- 7 files changed, 45 insertions(+), 26 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 0fb74ce..4a7d1b3 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -70,6 +70,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Harden TLS ServerHello parser — add explicit bounds check for oversized session ID length before advancing position ([#82]) - Refactor probe functions to use input structs per CS-5 — `probeTLS13Cipher`, `probeKeyExchangeGroup`, `probeQUICCipher`, `probeCipher`, `probeKeyExchangeGroupLegacy` now take `cipherProbeInput` ([#82]) - Convert `populateConnectResult` to a method `(*ConnectResult).populate` per CS-5 — reduces argument count from 3 to 2 (ctx + input) ([#82]) +- Convert `appendKeyShareExtension` to accept `appendKeyShareExtensionInput` struct per CS-5 — function had 3 arguments ([#82]) - **Breaking:** Rename `csr --cert` flag to `--from-cert` for clarity — avoids confusion with certificate file arguments in other commands ([#80]) - **Breaking:** `connect` JSON `sha256_fingerprint` format changed from lowercase hex to colon-separated uppercase hex for CLI-4 consistency with `inspect` and `sha1_fingerprint` ([#80]) - **Breaking:** Rename `CRLCheckResult.DistributionPoint` to `CRLCheckResult.URL` (JSON: `url`) and `OCSPResult.ResponderURL` to `OCSPResult.URL` (JSON: `url`) — consistent field name for the checked endpoint across both revocation types (CLI-4) ([#78]) @@ -103,6 +104,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Fix TOCTOU race in `spinner.Stop()` — remove started guard and use `stopOnce` unconditionally so Stop() is safe regardless of concurrency with Start() ([#82]) - Fix `connect` legacy probe running OCSP and CRL checks — revocation checks are now skipped for legacy probes since there is no cryptographic chain to verify revocation against; eliminates misleading `OCSP: skipped (no issuer certificate in chain)` output ([#82]) - Fix `connect` legacy fallback triggering on all TLS handshake failures — now only attempted on `tls.AlertError` (cipher negotiation failure), not network errors or certificate errors that would add a spurious 5-second timeout ([#82]) +- Fix `connect` error message swallowing `legacyErr` when legacy fallback also fails — both the original TLS alert and the legacy fallback error are now included ([#82]) +- Fix `spinner.Stop()` deadlock when called before `Start()` — Stop() now closes `done` via `startOnce` so `<-s.done` never blocks ([#82]) +- Fix uppercase `QUIC` and `TLS` in error strings in `quicprobe.go`, `legacyprobe.go`, and `tls13probe.go` violating ERR-4 ([#82]) - Fix `connect --ciphers` diagnostics filter using in-place slice aliasing — now allocates a new slice to avoid confusing aliasing semantics ([#82]) - Fix bare error returns in `deriveTrafficKeys` — wrap with `%w` context per ERR-1 ([#82]) - Fix `SupportedVersions` missing QUIC-only TLS versions — QUIC cipher versions now added to version set alongside TCP ciphers ([`bed32df`]) @@ -193,6 +197,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 - Remove `TestBuildLegacyClientHelloMsg` — behavioral coverage exists through `TestLegacyFallbackConnect` per T-11 ([`6492fa5`]) - Remove `TestParseCertificateMessage` — behavioral coverage exists through `TestReadServerCertificates` per T-11 ([#82]) +- Fix `_, _` error discards in `TestLegacyFallbackConnect` mock server goroutine — replaced with `slog.Debug` per ERR-5 ([#82]) - Remove `TestCipherSuiteNameLegacyIDs` — behavioral coverage exists through `TestScanCipherSuites` per T-11 ([#82]) - Strengthen `TestBuildQUICInitialPacket` — verify QUIC v1 version, DCID/SCID in header, and round-trip decrypt CRYPTO frame against original ClientHello ([#82]) - Consolidate `TestRateCipherSuite` from 13 entries to 6 — one per distinct code path (T-12) ([#82]) diff --git a/cmd/certkit/spinner.go b/cmd/certkit/spinner.go index 3243071..e981af8 100644 --- a/cmd/certkit/spinner.go +++ b/cmd/certkit/spinner.go @@ -53,8 +53,11 @@ func (s *spinner) SetMessage(msg string) { s.mu.Unlock() } -// Stop halts the spinner and clears the line. Safe to call multiple times. +// Stop halts the spinner and clears the line. Safe to call before or after +// Start(), and safe to call multiple times. func (s *spinner) Stop() { + // If Start() was never called, close done so <-s.done does not block. + s.startOnce.Do(func() { close(s.done) }) s.stopOnce.Do(func() { close(s.stop) }) <-s.done } diff --git a/connect.go b/connect.go index a11760b..2fb22f6 100644 --- a/connect.go +++ b/connect.go @@ -333,7 +333,7 @@ func ConnectTLS(ctx context.Context, input ConnectTLSInput) (*ConnectResult, err serverName: serverName, }) if legacyErr != nil { - return nil, fmt.Errorf("tls handshake with %s: %w", addr, handshakeErr) + return nil, fmt.Errorf("tls handshake with %s: %w; legacy fallback: %v", addr, handshakeErr, legacyErr) } result := &ConnectResult{ Host: input.Host, @@ -885,7 +885,7 @@ func RateCipherSuite(cipherID uint16, tlsVersion uint16) CipherRating { // For TLS 1.0–1.2: look up the cipher suite name to classify. name := tls.CipherSuiteName(cipherID) - // Non-ECDHE key exchange (static RSA) is insecure — no forward secrecy. + // Non-ECDHE key exchange (static RSA, DHE/DSS) is weak — no modern forward secrecy guarantees. if !strings.Contains(name, "ECDHE") { return CipherRatingWeak } diff --git a/legacyprobe.go b/legacyprobe.go index 3037c13..699e92c 100644 --- a/legacyprobe.go +++ b/legacyprobe.go @@ -181,9 +181,9 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat header := make([]byte, 5) if _, err := io.ReadFull(r, header); err != nil { if shResult != nil { - return shResult, certs, fmt.Errorf("reading TLS record: %w", err) + return shResult, certs, fmt.Errorf("reading tls record: %w", err) } - return nil, nil, fmt.Errorf("reading TLS record header: %w", err) + return nil, nil, fmt.Errorf("reading tls record header: %w", err) } totalRead += 5 @@ -201,7 +201,7 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat payload := make([]byte, recordLen) if _, err := io.ReadFull(r, payload); err != nil { - return shResult, certs, fmt.Errorf("reading TLS record payload: %w", err) + return shResult, certs, fmt.Errorf("reading tls record payload: %w", err) } totalRead += recordLen @@ -214,7 +214,7 @@ func readServerCertificates(r io.Reader) (*serverHelloResult, []*x509.Certificat } if contentType != 0x16 { - return shResult, certs, fmt.Errorf("unexpected TLS content type: 0x%02x", contentType) + return shResult, certs, fmt.Errorf("unexpected tls content type: 0x%02x", contentType) } // Append to handshake buffer and process complete messages. diff --git a/legacyprobe_test.go b/legacyprobe_test.go index d05e272..60a4c8d 100644 --- a/legacyprobe_test.go +++ b/legacyprobe_test.go @@ -8,6 +8,7 @@ import ( "crypto/x509" "crypto/x509/pkix" "errors" + "log/slog" "math/big" "net" "strings" @@ -115,7 +116,7 @@ func TestReadServerCertificates(t *testing.T) { { name: "unexpected content type", records: buildRawTLSRecord(0x17, 1), // ApplicationData - wantErrContains: "unexpected TLS content type", + wantErrContains: "unexpected tls content type", }, } @@ -292,7 +293,9 @@ func TestLegacyFallbackConnect(t *testing.T) { } // Read the ClientHello (we don't parse it, just consume it). buf := make([]byte, 4096) - _, _ = conn.Read(buf) + if _, err := conn.Read(buf); err != nil { + slog.Debug("TestLegacyFallbackConnect: reading ClientHello", "error", err) + } // Send ServerHello + Certificate as raw TLS records. serverHello := buildMockServerHello(0x0303, 0x0033) @@ -305,7 +308,9 @@ func TestLegacyFallbackConnect(t *testing.T) { handshake = append(handshake, certMsg...) handshake = append(handshake, helloDone...) - _, _ = conn.Write(wrapTLSRecord(handshake)) + if _, err := conn.Write(wrapTLSRecord(handshake)); err != nil { + slog.Debug("TestLegacyFallbackConnect: writing server response", "error", err) + } _ = conn.Close() } }() diff --git a/quicprobe.go b/quicprobe.go index 9ff9b98..c07c487 100644 --- a/quicprobe.go +++ b/quicprobe.go @@ -119,7 +119,7 @@ type quicInitialPacketInput struct { func buildQUICInitialPacket(input quicInitialPacketInput) ([]byte, error) { clientKeys, _, err := deriveQUICInitialKeys(input.dcid) if err != nil { - return nil, fmt.Errorf("deriving QUIC keys: %w", err) + return nil, fmt.Errorf("deriving quic keys: %w", err) } // Build CRYPTO frame: type(1) + offset(var) + length(var) + data @@ -354,7 +354,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve } plaintext, err := gcm.Open(nil, nonce, packet[ciphertextStart:payloadEnd], associatedData) if err != nil { - return nil, fmt.Errorf("decrypting QUIC payload: %w", err) + return nil, fmt.Errorf("decrypting quic payload: %w", err) } // Find the CRYPTO frame in the plaintext. @@ -462,7 +462,7 @@ func parseQUICInitialResponse(packet []byte, serverKeys quicInitialKeys) (*serve return parseServerHello(cryptoData) } - return nil, fmt.Errorf("no crypto frame found in QUIC Initial response") + return nil, fmt.Errorf("no crypto frame found in quic initial response") } // probeQUICCipher sends a QUIC Initial packet to the provided UDP address diff --git a/tls13probe.go b/tls13probe.go index a9e7309..6dcb406 100644 --- a/tls13probe.go +++ b/tls13probe.go @@ -103,7 +103,7 @@ func buildClientHelloMsg(input clientHelloInput) ([]byte, error) { exts = appendSNIExtension(exts, input.serverName) exts = appendSupportedGroupsExtension(exts, input.groupID) exts = appendSignatureAlgorithmsExtension(exts) - exts = appendKeyShareExtension(exts, input.groupID, keyShareData) + exts = appendKeyShareExtension(exts, appendKeyShareExtensionInput{groupID: input.groupID, keyData: keyShareData}) exts = appendSupportedVersionsExtension(exts) exts = appendPSKKeyExchangeModesExtension(exts) if len(input.alpn) > 0 { @@ -249,7 +249,7 @@ func readServerHello(r io.Reader) (*serverHelloResult, error) { // Read TLS record header (5 bytes): type(1) + version(2) + length(2). header := make([]byte, 5) if _, err := io.ReadFull(r, header); err != nil { - return nil, fmt.Errorf("reading TLS record header: %w", err) + return nil, fmt.Errorf("reading tls record header: %w", err) } contentType := header[0] @@ -262,7 +262,7 @@ func readServerHello(r io.Reader) (*serverHelloResult, error) { payload := make([]byte, recordLen) if _, err := io.ReadFull(r, payload); err != nil { - return nil, fmt.Errorf("reading TLS record payload: %w", err) + return nil, fmt.Errorf("reading tls record payload: %w", err) } // Alert record: the server rejected the cipher suite or group. @@ -271,7 +271,7 @@ func readServerHello(r io.Reader) (*serverHelloResult, error) { } if contentType != 0x16 { - return nil, fmt.Errorf("unexpected TLS content type: 0x%02x", contentType) + return nil, fmt.Errorf("unexpected tls content type: 0x%02x", contentType) } return parseServerHello(payload) @@ -509,16 +509,22 @@ func appendSignatureAlgorithmsExtension(b []byte) []byte { return appendUint16(b, 0x0401) // rsa_pkcs1_sha256 } +// appendKeyShareExtensionInput contains parameters for appendKeyShareExtension. +type appendKeyShareExtensionInput struct { + groupID tls.CurveID + keyData []byte +} + // appendKeyShareExtension appends a key_share extension (0x0033). -func appendKeyShareExtension(b []byte, groupID tls.CurveID, keyData []byte) []byte { - entryLen := 2 + 2 + len(keyData) // group(2) + key_len(2) + key_data - - b = appendUint16(b, 0x0033) // extension type - b = appendUint16(b, uint16(2+entryLen)) // extension data length - b = appendUint16(b, uint16(entryLen)) // client key shares length - b = appendUint16(b, uint16(groupID)) // named group - b = appendUint16(b, uint16(len(keyData))) - return append(b, keyData...) +func appendKeyShareExtension(b []byte, input appendKeyShareExtensionInput) []byte { + entryLen := 2 + 2 + len(input.keyData) // group(2) + key_len(2) + key_data + + b = appendUint16(b, 0x0033) // extension type + b = appendUint16(b, uint16(2+entryLen)) // extension data length + b = appendUint16(b, uint16(entryLen)) // client key shares length + b = appendUint16(b, uint16(input.groupID)) // named group + b = appendUint16(b, uint16(len(input.keyData))) + return append(b, input.keyData...) } // appendSupportedVersionsExtension appends a supported_versions extension (0x002b)