Make sure that is_verified is a boolean when processing room keys

changelog.d/7045.misc

@@ -0,0 +1 @@
+Add a type check to `is_verified` when processing room keys.

synapse/handlers/e2e_room_keys.py

@@ -207,6 +207,13 @@ def upload_room_keys(self, user_id, version, room_keys):
             changed = False  # if anything has changed, we need to update the etag
             for room_id, room in iteritems(room_keys["rooms"]):
                 for session_id, room_key in iteritems(room["sessions"]):
+                    if not isinstance(room_key["is_verified"], bool):
+                        msg = (
+                            "is_verified must be a boolean in keys for room %s"
+                            % room_id
+                        )
+                        raise SynapseError(400, msg, Codes.INVALID_PARAM)
+
                     log_kv(
                         {
                             "message": "Trying to upload room key",