Add an option to disable autojoin for guest accounts (#6637)

Fixes https://github.com/matrix-org/synapse/issues/3177

2 files changed, 15 insertions, 1 deletions

diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index a9aa8c3737..fecced2d57 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -128,6 +128,7 @@ class RegistrationConfig(Config):
             if not RoomAlias.is_valid(room_alias):
                 raise ConfigError("Invalid auto_join_rooms entry %s" % (room_alias,))
         self.autocreate_auto_join_rooms = config.get("autocreate_auto_join_rooms", True)
+        self.auto_join_rooms_for_guests = config.get("auto_join_rooms_for_guests", True)
 
         self.enable_set_displayname = config.get("enable_set_displayname", True)
         self.enable_set_avatar_url = config.get("enable_set_avatar_url", True)
@@ -368,6 +369,13 @@ class RegistrationConfig(Config):
         # users cannot be auto-joined since they do not exist.
         #
         #autocreate_auto_join_rooms: true
+
+        # When auto_join_rooms is specified, setting this flag to false prevents
+        # guest accounts from being automatically joined to the rooms.
+        #
+        # Defaults to true.
+        #
+        #auto_join_rooms_for_guests: false
         """
             % locals()
         )
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index ffda09226c..5c7113a3bb 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -244,7 +244,13 @@ class RegistrationHandler(BaseHandler):
                     fail_count += 1
 
         if not self.hs.config.user_consent_at_registration:
-            yield defer.ensureDeferred(self._auto_join_rooms(user_id))
+            if not self.hs.config.auto_join_rooms_for_guests and make_guest:
+                logger.info(
+                    "Skipping auto-join for %s because auto-join for guests is disabled",
+                    user_id,
+                )
+            else:
+                yield defer.ensureDeferred(self._auto_join_rooms(user_id))
         else:
             logger.info(
                 "Skipping auto-join for %s because consent is required at registration",