Credentials stored at rest were left world-readable on multi-user hosts:
- TokenManager._get_secure_storage_path() documented its credential dir as
mode 0o700 but created it via mkdir() with default perms (0o755), leaving
the Fernet secret.key and encrypted tokens.enc in a traversable dir.
- Settings.dump() persisted tool_repository_password (plaintext) to
settings.json via open("w"), producing a 0o644 file, and created the
config dir at 0o755 — despite the sibling token_manager already writing
secrets atomically at 0o600.
Fixes:
- TokenManager: chmod the credential dir to 0o700 after mkdir (robust against
umask and pre-existing dirs).
- Settings: write settings.json atomically at 0o600 (mkstemp + chmod +
os.replace) and chmod the dedicated config dir to 0o700. The /tmp and cwd
fallback parents are deliberately not chmod'd; the 0o600 file mode protects
the credential there.
Adds regression tests asserting 0o600 files and 0o700 dirs, and that shared
fallback dirs are not globally tightened.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
