Add per user ratelimiting overrides

synapse/handlers/_base.py

@@ -53,7 +53,20 @@ class BaseHandler(object):
 
         self.event_builder_factory = hs.get_event_builder_factory()
 
-    def ratelimit(self, requester):
+    @defer.inlineCallbacks
+    def ratelimit(self, requester, update=True):
+        """Ratelimits requests.
+
+        Args:
+            requester (Requester)
+            update (bool): Whether to record that a request is being processed.
+                Set to False when doing multiple checks for one request (e.g.
+                to check up front if we would reject the request), and set to
+                True for the last call for a given request.
+
+        Raises:
+            LimitExceededError if the request should be ratelimited
+        """
         time_now = self.clock.time()
         user_id = requester.user.to_string()
 
@@ -67,10 +80,25 @@ class BaseHandler(object):
         if requester.app_service and not requester.app_service.is_rate_limited():
             return
 
+        # Check if there is a per user override in the DB.
+        override = yield self.store.get_ratelimit_for_user(user_id)
+        if override:
+            # If overriden with a null Hz then ratelimiting has been entirely
+            # disabled for the user
+            if not override.messages_per_second:
+                return
+
+            messages_per_second = override.messages_per_second
+            burst_count = override.burst_count
+        else:
+            messages_per_second = self.hs.config.rc_messages_per_second
+            burst_count = self.hs.config.rc_message_burst_count
+
         allowed, time_allowed = self.ratelimiter.send_message(
             user_id, time_now,
-            msg_rate_hz=self.hs.config.rc_messages_per_second,
-            burst_count=self.hs.config.rc_message_burst_count,
+            msg_rate_hz=messages_per_second,
+            burst_count=burst_count,
+            update=update,
         )
         if not allowed:
             raise LimitExceededError(

synapse/handlers/message.py

@@ -16,7 +16,7 @@
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.api.errors import AuthError, Codes, SynapseError, LimitExceededError
+from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.events.utils import serialize_event
 from synapse.events.validator import EventValidator
@@ -254,17 +254,7 @@ class MessageHandler(BaseHandler):
         # We check here if we are currently being rate limited, so that we
         # don't do unnecessary work. We check again just before we actually
         # send the event.
-        time_now = self.clock.time()
-        allowed, time_allowed = self.ratelimiter.send_message(
-            event.sender, time_now,
-            msg_rate_hz=self.hs.config.rc_messages_per_second,
-            burst_count=self.hs.config.rc_message_burst_count,
-            update=False,
-        )
-        if not allowed:
-            raise LimitExceededError(
-                retry_after_ms=int(1000 * (time_allowed - time_now)),
-            )
+        yield self.ratelimit(requester, update=False)
 
         user = UserID.from_string(event.sender)
 
@@ -499,7 +489,7 @@ class MessageHandler(BaseHandler):
         # We now need to go and hit out to wherever we need to hit out to.
 
         if ratelimit:
-            self.ratelimit(requester)
+            yield self.ratelimit(requester)
 
         try:
             yield self.auth.check_from_context(event, context)

synapse/handlers/profile.py

@@ -156,7 +156,7 @@ class ProfileHandler(BaseHandler):
         if not self.hs.is_mine(user):
             return
 
-        self.ratelimit(requester)
+        yield self.ratelimit(requester)
 
         room_ids = yield self.store.get_rooms_for_user(
             user.to_string(),

synapse/handlers/room.py

@@ -75,7 +75,7 @@ class RoomCreationHandler(BaseHandler):
         """
         user_id = requester.user.to_string()
 
-        self.ratelimit(requester)
+        yield self.ratelimit(requester)
 
         if "room_alias_name" in config:
             for wchar in string.whitespace: