Handle failures in parsing parameters

tests/test_configuration.py

@@ -1722,6 +1722,29 @@ def _output():
         resp = app.get('/test', status=403)
         assert 'ERROR!!!' in resp, resp
 
+    def test_custom_error_document_handles_malformed_query_string(self):
+        class ErrorController(TGController):
+            @expose()
+            def document(self, *args, **kw):
+                return 'ERROR!!!'
+
+        class RootController(TGController):
+            error = ErrorController()
+
+            @expose()
+            def test(self):
+                return 'OK'
+
+        conf = AppConfig(minimal=True, root_controller=RootController())
+        conf['errorpage.enabled'] = True
+        conf['errorpage.status_codes'] = [400]
+        conf['errorpage.handle_exceptions'] = False
+        app = conf.make_wsgi_app(full_stack=True)
+        app = TestApp(app)
+
+        resp = app.get('/test?x=%AD', status=400)
+        assert 'ERROR!!!' in resp, resp
+
     def test_error_document_passthrough(self):
         class ErrorController(TGController):
             @expose()

tests/test_tg_controller_dispatch.py

@@ -619,6 +619,12 @@ def test_named_arguments_override_positional(self):
         r = self.app.get('/hello/YourName/silly?name=You&more=1')
         assert 'Hello You' in r, r
 
+    def test_malformed_query_parameter_name_is_bad_request(self):
+        self.app.get('/?percent%ADd=1', status=400)
+
+    def test_malformed_query_parameter_value_is_bad_request(self):
+        self.app.get('/?x=%AD', status=400)
+
     def test_response_without_charset(self):
         r = self.app.get('/index_unicode')
         assert 'Hello World' in r, r

tg/request_local.py

@@ -130,7 +130,11 @@ def args_params(self):
         # This was: dict(((str(n), v) for n,v in self.params.mixed().items()))
         # so that keys were all strings making possible to use them as arguments.
         # Now it seems that all keys are always strings, did WebOb change behavior?
-        params = self.params.mixed()
+        try:
+            params = self.params.mixed()
+        except UnicodeDecodeError:
+            self.__dict__["args_params"] = {}
+            raise HTTPBadRequest("Invalid request parameters")
         if (
             self.content_type
             and self.content_type.lower() == "application/json"