bug: govern-shell.sh — unescaped $COMMAND in printf creates malformed JSON, silently defaults to allow

[jpleva91]

Bug

scripts/govern-shell.sh constructs the governance evaluation JSON using printf with an unescaped variable:

RESULT=$(printf '{"tool":"run_shell","action":"%s","path":"."}' "$COMMAND" | shellforge evaluate 2>/dev/null || echo '{"allowed":true}')

Problem

If $COMMAND contains JSON special characters — double quotes, backslashes, newlines, or control characters — the resulting JSON is malformed. Examples:

Command	Output
echo "hello"	{"tool":"run_shell","action":"echo "hello"","path":"."} ← invalid JSON
sed 's/foo/bar/'	breaks shellforge evaluate JSON parsing
printf "\n"	embeds literal newline into JSON string

Impact

When shellforge evaluate receives malformed JSON, it unmarshal-fails and (due to issue #62) defaults to allow. The || echo '{"allowed":true}' fallback also hides the error. Net result: governance check is silently bypassed for any command with quotes or backslashes — a very common case in shell usage.

Fix

Use jq to safely construct the JSON payload:

RESULT=$(jq -n --arg cmd "$COMMAND" '{"tool":"run_shell","action":$cmd,"path":"."}' | shellforge evaluate 2>/dev/null || echo '{"allowed":true}')

Or use printf '%s' with a heredoc approach. At minimum, escape the command string before interpolation.

Related

• Issue bug: govern-shell.sh uses fragile sed to parse JSON — denial reason extraction can fail silently #67 — fragile sed JSON parsing on the output side
• Issue bug: cmdEvaluate silently ignores JSON unmarshal error — governance bypass #62 — cmdEvaluate ignores unmarshal errors, defaults to allow

Severity: Medium — governance bypass for any shell command containing quotes or backslashes, which is normal in real agent usage.