From 197c14dbcfa9bc5bb281833a91ee035cb154216d Mon Sep 17 00:00:00 2001
From: David Baker <dave@matrix.org>
Date: Wed, 4 Oct 2017 10:47:54 +0100
Subject: [PATCH] Add room creation checks to spam checker

Lets the spam checker deny attempts to create rooms and add aliases
to them.
---
 synapse/events/spamcheck.py   | 32 ++++++++++++++++++++++++++++++++
 synapse/handlers/directory.py |  7 +++++++
 synapse/handlers/room.py      |  8 ++++++++
 3 files changed, 47 insertions(+)

diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
index 8b01c091e..7cb3468df 100644
--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@@ -61,3 +61,35 @@ class SpamChecker(object):
             return True
 
         return self.spam_checker.user_may_invite(userid, room_id)
+
+    def user_may_create_room(self, userid):
+        """Checks if a given user may create a room
+
+        If this method returns false, the creation request will be rejected.
+
+        Args:
+            userid (string): The sender's user ID
+
+        Returns:
+            bool: True if the user may create a room, otherwise False
+        """
+        if self.spam_checker is None:
+            return True
+
+        return self.spam_checker.user_may_create_room(userid)
+
+    def user_may_create_room_alias(self, userid, room_alias):
+        """Checks if a given user may create a room alias
+
+        If this method returns false, the association request will be rejected.
+
+        Args:
+            userid (string): The sender's user ID
+
+        Returns:
+            bool: True if the user may create a room alias, otherwise False
+        """
+        if self.spam_checker is None:
+            return True
+
+        return self.spam_checker.user_may_create_room_alias(userid, room_alias)
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 943554ce9..ed18bb20b 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -40,6 +40,8 @@ class DirectoryHandler(BaseHandler):
             "directory", self.on_directory_query
         )
 
+        self.spam_checker = hs.get_spam_checker()
+
     @defer.inlineCallbacks
     def _create_association(self, room_alias, room_id, servers=None, creator=None):
         # general association creation for both human users and app services
@@ -73,6 +75,11 @@ class DirectoryHandler(BaseHandler):
         # association creation for human users
         # TODO(erikj): Do user auth.
 
+        if not self.spam_checker.user_may_create_room_alias(user_id, room_alias):
+            raise SynapseError(
+                403, "This user is not permitted to create this alias",
+            )
+
         can_create = yield self.can_modify_alias(
             room_alias,
             user_id=user_id
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 5698d2808..f909ea04f 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -60,6 +60,11 @@ class RoomCreationHandler(BaseHandler):
         },
     }
 
+    def __init__(self, hs):
+        super(RoomCreationHandler, self).__init__(hs)
+
+        self.spam_checker = hs.get_spam_checker()
+
     @defer.inlineCallbacks
     def create_room(self, requester, config, ratelimit=True):
         """ Creates a new room.
@@ -75,6 +80,9 @@ class RoomCreationHandler(BaseHandler):
         """
         user_id = requester.user.to_string()
 
+        if not self.spam_checker.user_may_create_room(user_id):
+                raise SynapseError(403, "You are not permitted to create rooms")
+
         if ratelimit:
             yield self.ratelimit(requester)