🛡️ Sentinel: [CRITICAL] Fix unhandled AttributeError in SafeStaticFiles bypass

.jules/sentinel.md

@@ -1,4 +1,4 @@
-## 2025-02-21 - Path Traversal in Mix Endpoint API Parameter
-**Vulnerability:** The `/projects/{project_id}/mix` API endpoint in `src/audioformation/server/routes.py` accepted a `music` parameter (meant to specify a filename within the `05_MUSIC/generated` directory) but directly passed it to `mix_project` without sanitization. This allowed directory traversal payloads like `../../../etc/passwd` to be used for background music resolution.
-**Learning:** Even internal API inputs that map strictly to filenames inside an expected directory must be sanitized. A simple check for file existence (`if not bg_music_path.exists():`) is insufficient as it confirms existence but allows looking outside the bounded directory.
-**Prevention:** Always use established sanitization helpers (like `sanitize_filename`) or bound checks (like `validate_path_within`) for any user-supplied string that forms part of a filesystem path. Ensure bypass parameters like `FORCE_NO_MUSIC` are handled before and mutually exclusively from sanitization.
+## 2025-02-24 - Exception Handling in SafeStaticFiles
+**Vulnerability:** SafeStaticFiles incorrectly normalizes `path` to lowercase using `p = Path(path).lower()`, but `Path` objects don't have a `.lower()` method. This throws an `AttributeError` instead of handling the security check and raises an unhandled internal error.
+**Learning:** Security controls can bypass themselves if they contain runtime bugs that cause unhandled exceptions ("fail open" or unpredictable error responses). String operations must be done before path instantiation, e.g. `Path(str(path).lower())`.
+**Prevention:** Always validate that security logic functions fail cleanly or correctly and handle edge-cases and None-type values properly to avoid breaking applications.

src/audioformation/server/app.py

@@ -24,7 +24,7 @@ class SafeStaticFiles(StaticFiles):
 
     async def get_response(self, path: str, scope) -> Response:
         # Normalize path for check
-        p = Path(path).lower()
+        p = Path(str(path).lower())
         if "00_config" in p.parts or p.name.startswith(".env") or ".git" in p.parts:
             raise HTTPException(
                 status_code=403, detail="Access denied to sensitive resource"