[verified] fix files list owner scoping

routers/database/files/files_simplified.py

@@ -26,6 +26,24 @@ auth = SupabaseBearer()
 
 logger = initialise_logger(__name__, os.getenv("LOG_LEVEL"), os.getenv("LOG_PATH"), 'default', True)
 
+def _user_id_from_payload(payload: Dict[str, Any]) -> str:
+    user_id = payload.get('sub') or payload.get('user_id')
+    if not user_id:
+        raise HTTPException(status_code=401, detail="Invalid token payload")
+    return user_id
+
+def _cabinet_visible_to_user(client: SupabaseServiceRoleClient, cabinet_id: str, user_id: str) -> bool:
+    """Require cabinet ownership before service-role reads file metadata."""
+    owned = (
+        client.supabase.table('file_cabinets')
+        .select('id')
+        .eq('id', cabinet_id)
+        .eq('user_id', user_id)
+        .limit(1)
+        .execute()
+    )
+    return bool(owned.data)
+
 def _choose_bucket(scope: str, user_id: str, school_id: Optional[str]) -> str:
     """Choose appropriate bucket based on scope - matches old system logic."""
     scope = (scope or 'teacher').lower()
@@ -134,7 +152,10 @@ async def upload_file(
 @router.get("/files")
 def list_files(cabinet_id: str, payload: Dict[str, Any] = Depends(auth)):
     """List files in a cabinet."""
+    user_id = _user_id_from_payload(payload)
     client = SupabaseServiceRoleClient()
+    if not _cabinet_visible_to_user(client, cabinet_id, user_id):
+        return []
     res = client.supabase.table('files').select('*').eq('cabinet_id', cabinet_id).execute()
     return res.data