Merge pull request #2492 from matrix-org/dbkr/spam_check_invites

Allow spam checker to reject invites too

synapse/events/spamcheck.py

@@ -45,3 +45,19 @@ class SpamChecker(object):
             return False
 
         return self.spam_checker.check_event_for_spam(event)
+
+    def user_may_invite(self, userid, room_id):
+        """Checks if a given user may send an invite
+
+        If this method returns false, the invite will be rejected.
+
+        Args:
+            userid (string): The sender's user ID
+
+        Returns:
+            bool: True if the user may send an invite, otherwise False
+        """
+        if self.spam_checker is None:
+            return True
+
+        return self.spam_checker.user_may_invite(userid, room_id)

synapse/handlers/federation.py

@@ -77,6 +77,7 @@ class FederationHandler(BaseHandler):
         self.action_generator = hs.get_action_generator()
         self.is_mine_id = hs.is_mine_id
         self.pusher_pool = hs.get_pusherpool()
+        self.spam_checker = hs.get_spam_checker()
 
         self.replication_layer.set_handler(self)
 
@@ -1077,6 +1078,11 @@ class FederationHandler(BaseHandler):
         if self.hs.config.block_non_admin_invites:
             raise SynapseError(403, "This server does not accept room invites")
 
+        if not self.spam_checker.user_may_invite(event.sender, event.room_id):
+            raise SynapseError(
+                403, "This user is not permitted to send invites to this server"
+            )
+
         membership = event.content.get("membership")
         if event.type != EventTypes.Member or membership != Membership.INVITE:
             raise SynapseError(400, "The event was not an m.room.member invite event")

synapse/handlers/room_member.py

@@ -48,6 +48,7 @@ class RoomMemberHandler(BaseHandler):
         self.member_linearizer = Linearizer(name="member")
 
         self.clock = hs.get_clock()
+        self.spam_checker = hs.get_spam_checker()
 
         self.distributor = hs.get_distributor()
         self.distributor.declare("user_joined_room")
@@ -210,12 +211,26 @@ class RoomMemberHandler(BaseHandler):
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
 
-        if (effective_membership_state == "invite" and
-                self.hs.config.block_non_admin_invites):
+        if effective_membership_state == "invite":
+            block_invite = False
             is_requester_admin = yield self.auth.is_server_admin(
                 requester.user,
             )
             if not is_requester_admin:
+                if self.hs.config.block_non_admin_invites:
+                    logger.info(
+                        "Blocking invite: user is not admin and non-admin "
+                        "invites disabled"
+                    )
+                    block_invite = True
+
+                if not self.spam_checker.user_may_invite(
+                    requester.user.to_string(), room_id,
+                ):
+                    logger.info("Blocking invite due to spam checker")
+                    block_invite = True
+
+            if block_invite:
                 raise SynapseError(
                     403, "Invites have been disabled on this server",
                 )