1 files changed, 5 insertions, 0 deletions
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 53e0103b5b..ad3df7cc7d 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -72,6 +72,7 @@ class RoomMemberHandler(object):
         self.clock = hs.get_clock()
         self.spam_checker = hs.get_spam_checker()
         self._server_notices_mxid = self.config.server_notices_mxid
+        self._enable_lookup = hs.config.enable_3pid_lookup
 
         # This is only used to get at ratelimit function, and
         # maybe_kick_guest_users. It's fine there are multiple of these as
@@ -748,6 +749,10 @@ class RoomMemberHandler(object):
         Returns:
             str: the matrix ID of the 3pid, or None if it is not recognized.
         """
+        if not self._enable_lookup:
+            raise SynapseError(
+                403, "Looking up third-party identifiers is denied from this server",
+            )
         try:
             data = yield self.simple_http_client.get_json(
                 "%s%s/_matrix/identity/api/v1/lookup" % (id_server_scheme, id_server,),