Merge remote-tracking branch 'origin/release-v1.20.0' into bbz/info-mainline-1.20.0 github/bbz/info-mainline-1.20.0 bbz/info-mainline-1.20.0

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py

index 1efe60f3a7..075afdd32b 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -16,6 +16,7 @@
 
 import logging
 
+from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.types import GroupID
 
@@ -325,6 +326,9 @@ class GroupRoomServlet(RestServlet):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
+        if not GroupID.is_valid(group_id):
+            raise SynapseError(400, "%s was not legal group ID" % (group_id,))
+
         result = await self.groups_handler.get_rooms_in_group(
             group_id, requester_user_id
         )