🛡️ Sentinel: [HIGH] Fix path traversal and prefix bypass in LocalJsonStore and TerminalService

[hackerxj2010]

🚨 Severity: HIGH
💡 Vulnerability:

• Path traversal in LocalJsonStore (packages/documents/src/index.ts) allowed access to files outside the intended base directory using .. segments.
• Prefix bypass in TerminalService (services/terminal-service/src/index.ts) allowed accessing sibling directories that share a prefix with the allowed root (e.g., /app/workspace-secret vs /app/workspace).

🎯 Impact: Unauthorized file access or execution in arbitrary directories.

🔧 Fix:

• Hardened LocalJsonStore.toPath with segment validation for .. and absolute path prefix checking.
• Updated TerminalService.resolveCwd to ensure trailing separators are present on both paths before performing the startsWith check.

✅ Verification:

• Added a security test for LocalJsonStore (verified and then removed as per plan).
• Ran existing TerminalService unit tests.
• Ran full monorepo test suite (48 tests passed).

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PR created automatically by Jules for task 1996626724564265253 started by @hackerxj2010

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