fix(google_oauth): close TOCTOU window when saving credentials#16718
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CharlieKerfoot wants to merge 1 commit into
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fix(google_oauth): close TOCTOU window when saving credentials#16718CharlieKerfoot wants to merge 1 commit into
CharlieKerfoot wants to merge 1 commit into
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Salvaged via #19673 onto current main with conflict resolution (kept newer |
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Problem
save_credentials created the temp file via
open(tmp, "w")and only chmodedd it to 0o600 afterward. Between the create and the chmod, the file existed on disk at the process umask (commonly 0o644 aka publicly readable). On a multi-user host or a container with a permissive umask, another local user could read the Google OAuth refresh and access tokens during the short write window. The lock file at line 181 already opens withos.open(..., 0o600), so it makes sense for the credentials file to too.Fix
open(tmp, "w")+ lateros.chmodwithos.open(tmp, O_WRONLY|O_CREAT|O_EXCL, 0o600)wrapped inos.fdopen. The file never exists at any other mode.os.chmod(path.parent, 0o700)after mkdir, so sibling users can't traverse into the creds dir. Wrapped in try/except for Windows where POSIX modes aren't enforced (no-op).Tests
uv run pytest tests/agent/test_gemini_cloudcode.py85/85 tests passedhermes auth login google, verify ~/.hermes/google_oauth_credentials.json is mode 0600 and the parent dir is 0700