[PM-27260] SSO cookie vending

[dereknance]

🎟️ Tracking

PM-27260

📔 Objective

For self-hosted installs, the /api/sso-cookie-vendor endpoint provides clients with a means to obtain a cookie being used to authenticate requests at a reverse proxy, load balancer, etc.

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

[claude]

Claude finished @dereknance's task in 2m 31s —— View job

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Code Review: SSO Cookie Vending (Re-review)

Summary

This PR adds an SSO cookie vending endpoint for self-hosted installs, allowing clients to obtain authentication cookies from a reverse proxy/load balancer via a bitwarden:// redirect scheme.

Previous Findings - ALL RESOLVED

Status	Location	Description
RESOLVED	SsoCookieVendorController.cs:34	Case sensitivity mismatch fixed with StringComparison.OrdinalIgnoreCase

Changes Since Last Review

The latest commit (1dd81fa) adds [SelfHosted(SelfHostedOnly = true)] attribute to restrict the endpoint to self-hosted instances only. This follows the established pattern used in other controllers (e.g., SelfHostedOrganizationLicensesController, AccountsController).

Assessment

No issues identified. The implementation is well-structured with:

• Proper self-hosted restriction via attribute
• Case-insensitive configuration check matching ConfigResponseModel behavior
• Comprehensive test coverage (18 test cases)
• URL encoding of cookie values with Uri.EscapeDataString()
• DoS safeguards (max 20 shards, max 8192 URI length)
• Hardcoded bitwarden:// scheme preventing open redirect attacks
• Sentinel value (d=1) for truncation detection

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Generated with Claude Code

[github-actions]

Checkmarx One – Scan Summary & Details – c64e8a12-9f63-47b6-b3b0-cd14a6f766d3

New Issues (1)

Checkmarx found the following issues in this Pull Request

#	Severity	Issue	Source File / Package	Checkmarx Insight
1		CSRF	/src/Api/Vault/Controllers/CiphersController.cs: 293	details Method at line 293 of /src/Api/Vault/Controllers/CiphersController.cs gets a parameter from a user request from id. This parameter value flows t... Attack Vector

Fixed Issues (4)

Great job! The following issues were fixed in this Pull Request

Severity	Issue	Source File / Package
	CSRF	/src/Api/Vault/Controllers/CiphersController.cs: 1178
	CSRF	/src/Api/Vault/Controllers/CiphersController.cs: 1062
	CSRF	/src/Api/Vault/Controllers/CiphersController.cs: 1527
	CSRF	/src/Api/Vault/Controllers/CiphersController.cs: 1403

[codecov]

Codecov Report

❌ Patch coverage is 96.72131% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.09%. Comparing base (8fa323b) to head (1dd81fa).

Files with missing lines	Patch %	Lines
src/Api/Controllers/SsoCookieVendorController.cs	96.72%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@                           Coverage Diff                            @@
##           pm-29144-communication-in-config-api    #6903      +/-   ##
========================================================================
- Coverage                                 56.10%   56.09%   -0.01%     
========================================================================
  Files                                      1968     1969       +1     
  Lines                                     87027    87012      -15     
  Branches                                   7753     7757       +4     
========================================================================
- Hits                                      48825    48811      -14     
- Misses                                    36392    36396       +4     
+ Partials                                   1810     1805       -5     

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[coroiu]

Quality stuff!

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud