Fix possible crash in validator when 'client' key is mentioned in request body

oauth2_provider/oauth2_validators.py

@@ -202,19 +202,32 @@ def _load_application(self, client_id, request):
         If request.client was not set, load application instance for given
         client_id and store it in request.client
         """
-
-        # we want to be sure that request has the client attribute!
-        assert hasattr(request, "client"), '"request" instance has no "client" attribute'
-
+        if request.client:
+            # check for cached client, to save the db hit if this has already been loaded
+            if not isinstance(request.client, Application):
+                log.debug("request.client is not an Application, something else set request.client erroneously, resetting request.client.")
+                request.client = None
+            elif request.client.client_id != client_id:
+                log.debug("request.client client_id does not match the given client_id, resetting request.client.")
+                request.client = None
+            elif not request.client.is_usable(request):
+                log.debug("request.client is a valid Application, but is not usable, resetting request.client.")
+                request.client = None
+            else:
+                log.debug("request.client is a valid Application, reusing it.")
+                return request.client
         try:
-            request.client = request.client or Application.objects.get(client_id=client_id)
-            # Check that the application can be used (defaults to always True)
-            if not request.client.is_usable(request):
-                log.debug("Failed body authentication: Application %r is disabled" % (client_id))
+            # cache wasn't hit, load from db
+            log.debug("cache not hit, Loading application from database for client_id %r", client_id)
+            client = Application.objects.get(client_id=client_id)
+            if not client.is_usable(request):
+                log.debug("Failed to load application: Application %r is not usable" % (client_id))
                 return None
+            log.debug("Loaded application %r from database", client)
+            request.client = client
             return request.client
         except Application.DoesNotExist:
-            log.debug("Failed body authentication: Application %r does not exist" % (client_id))
+            log.debug("Failed to load application: Application %r does not exist" % (client_id))
             return None
 
     def _set_oauth2_error_on_request(self, request, access_token, scopes):
@@ -277,6 +290,7 @@ def client_authentication_required(self, request, *args, **kwargs):
             pass
 
         self._load_application(request.client_id, request)
+        log.debug("Determining if client authentication is required for client %r", request.client)
         if request.client:
             return request.client.client_type == AbstractApplication.CLIENT_CONFIDENTIAL
 

tests/test_authorization_code.py

@@ -1308,6 +1308,27 @@ def test_request_body_params(self):
         self.assertEqual(content["scope"], "read write")
         self.assertEqual(content["expires_in"], self.oauth2_settings.ACCESS_TOKEN_EXPIRE_SECONDS)
 
+    def test_request_body_params_client_typo(self):
+        """
+        Request an access token using client_type: public
+        """
+        self.client.login(username="test_user", password="123456")
+        authorization_code = self.get_auth()
+
+        token_request_data = {
+            "grant_type": "authorization_code",
+            "code": authorization_code,
+            "redirect_uri": "http://example.org",
+            "client": self.application.client_id,
+            "client_secret": CLEARTEXT_SECRET,
+        }
+
+        response = self.client.post(reverse("oauth2_provider:token"), data=token_request_data)
+        self.assertEqual(response.status_code, 401)
+
+        content = json.loads(response.content.decode("utf-8"))
+        self.assertEqual(content["error"], "invalid_client")
+
     def test_public(self):
         """
         Request an access token using client_type: public

tests/test_oauth2_validators.py

@@ -210,8 +210,52 @@ def test_client_authentication_required(self):
         self.request.client = ""
         self.assertTrue(self.validator.client_authentication_required(self.request))
 
-    def test_load_application_fails_when_request_has_no_client(self):
-        self.assertRaises(AssertionError, self.validator.authenticate_client_id, "client_id", {})
+    def test_load_application_loads_client_id_when_request_has_no_client(self):
+        self.request.client = None
+        application = self.validator._load_application("client_id", self.request)
+        self.assertEqual(application, self.application)
+
+    def test_load_application_uses_cached_when_request_has_valid_client_matching_client_id(self):
+        self.request.client = self.application
+        application = self.validator._load_application("client_id", self.request)
+        self.assertIs(application, self.application)
+        self.assertIs(self.request.client, self.application)
+
+    def test_load_application_succeeds_when_request_has_invalid_client_valid_client_id(self):
+        self.request.client = 'invalid_client'
+        application = self.validator._load_application("client_id", self.request)
+        self.assertEqual(application, self.application)
+        self.assertEqual(self.request.client, self.application)
+
+    def test_load_application_overwrites_client_on_client_id_mismatch(self):
+        another_application = Application.objects.create(
+            client_id="another_client_id",
+            client_secret=CLEARTEXT_SECRET,
+            user=self.user,
+            client_type=Application.CLIENT_PUBLIC,
+            authorization_grant_type=Application.GRANT_PASSWORD,
+        )
+        self.request.client = another_application
+        application = self.validator._load_application("client_id", self.request)
+        self.assertEqual(application, self.application)
+        self.assertEqual(self.request.client, self.application)
+        another_application.delete()
+
+    @mock.patch.object(Application, "is_usable")
+    def test_load_application_returns_none_when_client_not_usable_cached(self, mock_is_usable):
+        mock_is_usable.return_value = False
+        self.request.client = self.application
+        application = self.validator._load_application("client_id", self.request)
+        self.assertIsNone(application)
+        self.assertIsNone(self.request.client)
+
+    @mock.patch.object(Application, "is_usable")
+    def test_load_application_returns_none_when_client_not_usable_db_lookup(self, mock_is_usable):
+        mock_is_usable.return_value = False
+        self.request.client = None
+        application = self.validator._load_application("client_id", self.request)
+        self.assertIsNone(application)
+        self.assertIsNone(self.request.client)
 
     def test_rotate_refresh_token__is_true(self):
         self.assertTrue(self.validator.rotate_refresh_token(mock.MagicMock()))