fix(socialaccount): JWT: Prevent replay using JTI

ChangeLog.rst

@@ -9,6 +9,14 @@
   ``settings.ACCOUNT_LOGIN_BY_CODE_REQUIRED``.
 
 
+Security notice
+---------------
+
+- In case an ID token is used for authentication, the JTI is now respected to
+  prevent the possibility of replays instead of solely relying on the expiration
+  time.
+
+
 64.1.0 (2024-08-15)
 *******************
 

allauth/socialaccount/internal/jwtkit.py

@@ -1,4 +1,7 @@
 import json
+import time
+
+from django.core.cache import cache
 
 import jwt
 from cryptography.hazmat.backends import default_backend
@@ -58,6 +61,21 @@ def fetch_key(credential, keys_url, lookup):
     return alg, key
 
 
+def verify_jti(data: dict) -> None:
+    """
+    Put the JWT token on a blacklist to prevent replay attacks.
+    """
+    iss = data.get("iss")
+    exp = data.get("exp")
+    jti = data.get("jti")
+    if iss is None or exp is None or jti is None:
+        return
+    timeout = exp - time.time()
+    key = f"jwt:iss={iss},jti={jti}"
+    if not cache.add(key=key, value=True, timeout=timeout):
+        raise OAuth2Error("token already used")
+
+
 def verify_and_decode(
     *, credential, keys_url, issuer, audience, lookup_kid, verify_signature=True
 ):
@@ -81,6 +99,7 @@ def verify_and_decode(
             audience=audience,
             algorithms=algorithms,
         )
+        verify_jti(data)
         return data
     except jwt.PyJWTError as e:
         raise OAuth2Error("Invalid id_token") from e

allauth/socialaccount/internal/tests/test_jwtkit.py

@@ -0,0 +1,36 @@
+from datetime import timedelta
+
+from django.utils import timezone
+
+from allauth.socialaccount.internal.jwtkit import verify_and_decode
+from allauth.socialaccount.providers.apple.client import jwt_encode
+from allauth.socialaccount.providers.oauth2.client import OAuth2Error
+
+
+def test_verify_and_decode(enable_cache):
+    now = timezone.now()
+    payload = {
+        "iss": "https://accounts.google.com",
+        "azp": "client_id",
+        "aud": "client_id",
+        "sub": "108204268033311374519",
+        "hd": "example.com",
+        "locale": "en",
+        "iat": now,
+        "jti": "a4e9b64d5e31da48a2037216e4ba9a5f5f4f50a0",
+        "exp": now + timedelta(hours=1),
+    }
+    id_token = jwt_encode(payload, "secret")
+    for attempt in range(2):
+        try:
+            verify_and_decode(
+                credential=id_token,
+                keys_url="/",
+                issuer=payload["iss"],
+                audience=payload["aud"],
+                lookup_kid=False,
+                verify_signature=False,
+            )
+            assert attempt == 0
+        except OAuth2Error:
+            assert attempt == 1