Fix JWT OIDC decode yet again (#3466)

PBENCH-1182

JWT added yet another `DecodeError` in our API Key validation path in some
recent update. Instead of continuing to add specific errors to be converted
into a specific internal exception, just handle all exceptions in the primary
OIDC decode by attempting the token as an API key. If that fails, report the
API key validation error, and re-raise the original OIDC error.

(Note that `verify_auth` will in turn just report this error and act as if no
authentication token was given.)

lib/pbench/server/auth/__init__.py

@@ -27,10 +27,6 @@ def __str__(self) -> str:
         return self.message
 
 
-class OpenIDTokenInvalid(Exception):
-    pass
-
-
 class Connection:
     """Helper connection class for use by an OpenIDClient instance."""
 
@@ -359,23 +355,14 @@ def token_introspect(self, token: str) -> JSON:
                 "sub": <user_id>
             }
         """
-        try:
-            return jwt.decode(
-                token,
-                self._pem_public_key,
-                algorithms=[self._TOKEN_ALG],
-                audience=[self.client_id],
-                options={
-                    "verify_signature": True,
-                    "verify_aud": True,
-                    "verify_exp": True,
-                },
-            )
-        except (
-            jwt.ExpiredSignatureError,
-            jwt.InvalidSignatureError,
-            jwt.InvalidAudienceError,
-            jwt.InvalidAlgorithmError,
-            ValueError,
-        ) as exc:
-            raise OpenIDTokenInvalid() from exc
+        return jwt.decode(
+            token,
+            self._pem_public_key,
+            algorithms=[self._TOKEN_ALG],
+            audience=[self.client_id],
+            options={
+                "verify_signature": True,
+                "verify_aud": True,
+                "verify_exp": True,
+            },
+        )

lib/pbench/server/auth/auth.py

@@ -6,7 +6,7 @@
 from flask_restful import abort
 
 from pbench.server import PbenchServerConfig
-from pbench.server.auth import OpenIDClient, OpenIDTokenInvalid
+from pbench.server.auth import OpenIDClient
 from pbench.server.database.models.api_keys import APIKey
 from pbench.server.database.models.users import User
 
@@ -143,14 +143,15 @@ def verify_auth_oidc(auth_token: str) -> Optional[User]:
     """
     try:
         token_payload = oidc_client.token_introspect(token=auth_token)
-    except OpenIDTokenInvalid:
-        # The token is not a valid access token, fall through.
-        pass
     except Exception:
-        current_app.logger.exception(
-            "Unexpected exception occurred while verifying the auth token {}",
-            auth_token,
-        )
+        try:
+            return verify_auth_api_key(auth_token)
+        except Exception:
+            current_app.logger.exception(
+                "Unexpected exception occurred while verifying the API key {}",
+                auth_token,
+            )
+        raise
     else:
         # Extract what we want to cache from the access token
         user_id = token_payload["sub"]
@@ -168,12 +169,4 @@ def verify_auth_oidc(auth_token: str) -> Optional[User]:
             user.update(username=username, roles=roles)
         return user
 
-    try:
-        return verify_auth_api_key(auth_token)
-    except Exception:
-        current_app.logger.exception(
-            "Unexpected exception occurred while verifying the API key {}",
-            auth_token,
-        )
-
     return None

lib/pbench/test/unit/server/auth/test_auth.py

@@ -12,12 +12,7 @@
 
 from pbench.server import JSON
 import pbench.server.auth
-from pbench.server.auth import (
-    Connection,
-    OpenIDClient,
-    OpenIDClientError,
-    OpenIDTokenInvalid,
-)
+from pbench.server.auth import Connection, OpenIDClient, OpenIDClientError
 import pbench.server.auth.auth as Auth
 from pbench.test.unit.server import DRB_USER_ID
 from pbench.test.unit.server.conftest import jwt_secret
@@ -435,9 +430,8 @@ def test_token_introspect_exp(self, monkeypatch, rsa_keys):
         )
         oidc_client = OpenIDClient.construct_oidc_client(config)
 
-        with pytest.raises(OpenIDTokenInvalid) as exc:
+        with pytest.raises(jwt.exceptions.ExpiredSignatureError):
             oidc_client.token_introspect(token)
-        assert isinstance(exc.value.__cause__, jwt.exceptions.ExpiredSignatureError)
 
     def test_token_introspect_aud(self, monkeypatch, rsa_keys):
         """Verify .token_introspect() failure via audience error"""
@@ -449,9 +443,8 @@ def test_token_introspect_aud(self, monkeypatch, rsa_keys):
         config = mock_connection(monkeypatch, "them", public_key=rsa_keys["public_key"])
         oidc_client = OpenIDClient.construct_oidc_client(config)
 
-        with pytest.raises(OpenIDTokenInvalid) as exc:
+        with pytest.raises(jwt.exceptions.InvalidAudienceError):
             oidc_client.token_introspect(token)
-        assert isinstance(exc.value.__cause__, jwt.exceptions.InvalidAudienceError)
 
     def test_token_introspect_sig(self, monkeypatch, rsa_keys):
         """Verify .token_introspect() failure via signature error"""
@@ -465,10 +458,9 @@ def test_token_introspect_sig(self, monkeypatch, rsa_keys):
         )
         oidc_client = OpenIDClient.construct_oidc_client(config)
 
-        with pytest.raises(OpenIDTokenInvalid) as exc:
+        with pytest.raises(jwt.exceptions.InvalidSignatureError):
             # Make the signature invalid.
             oidc_client.token_introspect(token + "1")
-        assert isinstance(exc.value.__cause__, jwt.exceptions.InvalidSignatureError)
 
     def test_token_introspect_alg(self, monkeypatch, rsa_keys):
         """Verify .token_introspect() failure via algorithm error"""
@@ -483,9 +475,8 @@ def test_token_introspect_alg(self, monkeypatch, rsa_keys):
         )
         oidc_client = OpenIDClient.construct_oidc_client(config)
 
-        with pytest.raises(OpenIDTokenInvalid) as exc:
+        with pytest.raises(jwt.exceptions.InvalidAlgorithmError):
             oidc_client.token_introspect(generated_api_key)
-        assert isinstance(exc.value.__cause__, jwt.exceptions.InvalidAlgorithmError)
 
 
 @dataclass
@@ -671,7 +662,7 @@ def test_verify_auth_oidc_invalid(self, monkeypatch, rsa_keys, make_logger):
         monkeypatch.setattr(Auth, "oidc_client", oidc_client)
 
         def tio_exc(token: str) -> JSON:
-            raise OpenIDTokenInvalid()
+            raise Exception("OIDC validation is disabled")
 
         app = Flask("test-verify-auth-oidc-invalid")
         app.logger = make_logger
@@ -693,7 +684,7 @@ def test_verify_auth_api_key(
         monkeypatch.setattr(Auth, "oidc_client", oidc_client)
 
         def tio_exc(token: str) -> JSON:
-            raise OpenIDTokenInvalid()
+            raise Exception("OIDC validation is disabled")
 
         app = Flask("test_verify_auth_api_key")
         app.logger = make_logger
@@ -716,7 +707,7 @@ def test_verify_auth_api_key_invalid(
         monkeypatch.setattr(Auth, "oidc_client", oidc_client)
 
         def tio_exc(token: str) -> JSON:
-            raise OpenIDTokenInvalid()
+            raise Exception("OIDC validation is disabled")
 
         app = Flask("test_verify_auth_api_key_invalid")
         app.logger = make_logger