fix: validateOutputPath symlink bypass — resolve real path before safe-dir check#745
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Gonzih wants to merge 1 commit intogarrytan:mainfrom
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fix: validateOutputPath symlink bypass — resolve real path before safe-dir check#745Gonzih wants to merge 1 commit intogarrytan:mainfrom
Gonzih wants to merge 1 commit intogarrytan:mainfrom
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…cking safe dirs path.resolve() normalizes .. components but does NOT follow symlinks. A symlink inside /tmp or cwd pointing outside those dirs would pass the isPathWithin() check while the actual write goes to the symlink target. e.g.: ln -s /etc /tmp/evil; screenshot /tmp/evil/cron.d/payload → path.resolve gives /tmp/evil/cron.d/payload (passes check) → fs.writeFile writes to /etc/cron.d/payload (security fail) Fix: after the lexical check, call fs.realpathSync on the nearest existing ancestor directory and re-validate the real path. Falls back safely up the directory tree if the parent doesn't exist yet. Closes garrytan#665
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* fix: DNS rebinding protection checks AAAA (IPv6) records too Cherry-pick PR #744 by @Gonzih. Closes the IPv6-only DNS rebinding gap by checking both A and AAAA records independently. Co-Authored-By: Gonzih <gonzih@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: validateOutputPath symlink bypass — resolve real path before safe-dir check Cherry-pick PR #745 by @Gonzih. Adds a second pass using fs.realpathSync() to resolve symlinks after lexical path validation. Co-Authored-By: Gonzih <gonzih@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: validate saved URLs before navigation in restoreState Cherry-pick PR #751 by @Gonzih. Prevents navigation to cloud metadata endpoints or file:// URIs embedded in user-writable state files. Co-Authored-By: Gonzih <gonzih@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: telemetry-ingest uses anon key instead of service role key Cherry-pick PR #750 by @Gonzih. The service role key bypasses RLS and grants unrestricted database access — anon key + RLS is the right model for a public telemetry endpoint. Co-Authored-By: Gonzih <gonzih@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: killAgent() actually kills the sidebar claude subprocess Cherry-pick PR #743 by @Gonzih. Implements cross-process kill signaling via kill-file + polling pattern, tracks active processes per-tab. Co-Authored-By: Gonzih <gonzih@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix(design): bind server to localhost and validate reload paths Cherry-pick PR #803 by @garagon. Adds hostname: '127.0.0.1' to Bun.serve() and validates /api/reload paths are within cwd() or tmpdir(). Closes C1+C2 from security audit #783. Co-Authored-By: garagon <garagon@users.noreply.github.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: add auth gate to /inspector/events SSE endpoint (C3) The /inspector/events endpoint had no authentication, unlike /activity/stream which validates tokens. Now requires the same Bearer header or ?token= query param check. Closes C3 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: sanitize design feedback with trust boundary markers (C4+H5) Wrap user feedback in <user-feedback> XML markers with tag escaping to prevent prompt injection via malicious feedback text. Cap accumulated feedback to last 5 iterations to limit incremental poisoning. Closes C4 and H5 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: harden file/directory permissions to owner-only (C5+H9+M9+M10) Add mode 0o700 to all mkdirSync calls for state/session directories. Add mode 0o600 to all writeFileSync calls for session.json, chat.jsonl, and log files. Add umask 077 to setup script. Prevents auth tokens, chat history, and browser logs from being world-readable on multi-user systems. Closes C5, H9, M9, M10 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: TOCTOU race in setup symlink creation (C6) Remove the existence check before mkdir -p (it's idempotent) and validate the target isn't already a symlink before creating the link. Prevents a local attacker from racing between the check and mkdir to redirect SKILL.md writes. Closes C6 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: remove CORS wildcard, restrict to localhost (H1) Replace Access-Control-Allow-Origin: * with http://127.0.0.1 on sidebar tab/chat endpoints. The Chrome extension uses manifest host_permissions to bypass CORS entirely, so this only blocks malicious websites from making cross-origin requests. Closes H1 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: make cookie picker auth mandatory (H2) Remove the conditional if(authToken) guard that skipped auth when authToken was undefined. Now all cookie picker data/action routes reject unauthenticated requests. Closes H2 from security audit #783. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * fix: gate /health token on chrome-extension Origin header Only return the auth token in /health response when the request Origin starts with chrome-extension://. The Chrome extension always sends this origin via manifest host_permissions. Regular HTTP requests (including tunneled ones from ngrok/SSH) won't get the token. The extension also has a fallback path through background.js that reads the token from the state file directly. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * test: update server-auth test for chrome-extension Origin gating The test previously checked for 'localhost-only' comment. Now checks for 'chrome-extension://' since the token is gated on Origin header. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * chore: bump version and changelog (v0.15.7.0) Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Gonzih <gonzih@users.noreply.github.com> Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: garagon <garagon@users.noreply.github.com>
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The Bug
`validateOutputPath()` calls `path.resolve(filePath)` and then checks if the result is within the safe directories. `path.resolve` normalizes `..` components lexically but does not follow symlinks.
Attack:
```bash
ln -s /etc /tmp/evil
then: screenshot /tmp/evil/cron.d/payload
```
`path.resolve('/tmp/evil/cron.d/payload')` returns `/tmp/evil/cron.d/payload` which passes `isPathWithin(_, '/tmp')`, but the actual `fs.writeFile` follows the symlink and writes to `/etc/cron.d/payload`.
Issue #665. Also related to #667.
Fix
After the lexical check, resolve the real path of the nearest existing ancestor directory using `fs.realpathSync` and re-validate against safe directories. Handles the case where the output file doesn't exist yet (walks up the tree to find the nearest existing parent).
```
/tmp/evil/ → realpathSync → /etc/
/tmp/evil/cron.d/ → /etc/cron.d/ (not in SAFE_DIRECTORIES) → BLOCKED
```
sent from mStack