fix(identity): guard OAuth2 IdP role against unknown enum values

litellm/identity/oauth2.py

@@ -10,7 +10,7 @@ OAuth2 paths converge on the same construction surface.
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional, cast
+from typing import TYPE_CHECKING, Optional
 
 if TYPE_CHECKING:
     from litellm.proxy._types import LitellmUserRoles, UserAPIKeyAuth
@@ -38,12 +38,21 @@ def build_user_api_key_auth_from_oauth2_response(
     from litellm.proxy._types import LitellmUserRoles, UserAPIKeyAuth
 
     user_id: Optional[str] = response_data.get(user_id_field_name)
-    user_role: Optional[str] = response_data.get(user_role_field_name)
+    raw_role = response_data.get(user_role_field_name)
     user_team_id: Optional[str] = response_data.get(user_team_id_field_name)
 
+    user_role: Optional[LitellmUserRoles]
+    if raw_role is None:
+        user_role = None
+    else:
+        try:
+            user_role = LitellmUserRoles(raw_role)
+        except ValueError:
+            user_role = LitellmUserRoles.INTERNAL_USER
+
     return UserAPIKeyAuth(
         api_key=token,
         team_id=user_team_id,
         user_id=user_id,
-        user_role=cast("LitellmUserRoles", user_role),
+        user_role=user_role,
     )

tests/test_litellm/identity/test_oauth2_builder.py

@@ -4,7 +4,7 @@ import sys
 sys.path.insert(0, os.path.abspath("../.."))
 
 from litellm.identity import build_user_api_key_auth_from_oauth2_response
-from litellm.proxy._types import UserAPIKeyAuth
+from litellm.proxy._types import LitellmUserRoles, UserAPIKeyAuth
 
 
 def test_default_field_names_extract_from_introspection_response():
@@ -37,14 +37,33 @@ def test_custom_field_names_override_defaults():
 
 
 def test_missing_fields_default_to_none():
-    uak = build_user_api_key_auth_from_oauth2_response(
-        token="t", response_data={}
-    )
+    uak = build_user_api_key_auth_from_oauth2_response(token="t", response_data={})
     assert uak.user_id is None
     assert uak.user_role is None
     assert uak.team_id is None
 
 
+def test_unknown_idp_role_defaults_to_internal_user():
+    uak = build_user_api_key_auth_from_oauth2_response(
+        token="t", response_data={"sub": "u", "role": "definitely-not-a-role"}
+    )
+    assert uak.user_role == LitellmUserRoles.INTERNAL_USER
+
+
+def test_known_idp_role_passes_through():
+    uak = build_user_api_key_auth_from_oauth2_response(
+        token="t", response_data={"sub": "u", "role": "proxy_admin"}
+    )
+    assert uak.user_role == LitellmUserRoles.PROXY_ADMIN
+
+
+def test_missing_role_field_stays_none():
+    uak = build_user_api_key_auth_from_oauth2_response(
+        token="t", response_data={"sub": "u"}
+    )
+    assert uak.user_role is None
+
+
 def test_token_is_hashed_into_token_field():
     """The api_key is hashed by the UserAPIKeyAuth validator; the
     OAuth2 builder must not bypass that path."""