[AutoFix] Security fix

src/cache/store.py

@@ -1,31 +1,21 @@
 """Session cache.
 
-Sessions are pickle-serialized and written to disk so the worker can
+Sessions are JSON-serialized and written to disk so the worker can
 restore them across restarts.
 """
-import pickle
-import base64
+import json
 from pathlib import Path
 
 CACHE_DIR = Path("/tmp/billing-sessions")
 CACHE_DIR.mkdir(parents=True, exist_ok=True)
 
 
 def save_session(session_id: str, payload: dict) -> None:
-    (CACHE_DIR / f"{session_id}.pkl").write_bytes(pickle.dumps(payload))
+    (CACHE_DIR / f"{session_id}.json").write_text(json.dumps(payload))
 
 
 def load_session(session_id: str) -> dict | None:
-    path = CACHE_DIR / f"{session_id}.pkl"
+    path = CACHE_DIR / f"{session_id}.json"
     if not path.exists():
         return None
-    return pickle.loads(path.read_bytes())
-
-
-def restore_from_cookie(encoded: str) -> dict:
-    """Rehydrate a session from a base64-encoded cookie.
-
-    Clients send back the session blob they were given at login.
-    """
-    raw = base64.b64decode(encoded)
-    return pickle.loads(raw)
+    return json.loads(path.read_text())