Merge pull request #5477 from matrix-org/babolivier/third_party_rules…

…_3pid

Add third party rules hook for 3PID invites

changelog.d/5477.feature

@@ -0,0 +1 @@
+Allow server admins to define implementations of extra rules for allowing or denying incoming events.

synapse/events/third_party_rules.py

@@ -35,7 +35,10 @@ def __init__(self, hs):
  module, config = hs.config.third_party_event_rules
 
  if module is not None:
- self.third_party_rules = module(config=config)
+ self.third_party_rules = module(
+ config=config,
+ http_client=hs.get_simple_http_client(),
+ )
 
  @defer.inlineCallbacks
  def check_event_allowed(self, event, context):
@@ -81,3 +84,31 @@ def on_create_room(self, requester, config, is_requester_admin):
  yield self.third_party_rules.on_create_room(
  requester, config, is_requester_admin
  )
+
+ @defer.inlineCallbacks
+ def check_threepid_can_be_invited(self, medium, address, room_id):
+ """Check if a provided 3PID can be invited in the given room.
+
+ Args:
+ medium (str): The 3PID's medium.
+ address (str): The 3PID's address.
+ room_id (str): The room we want to invite the threepid to.
+
+ Returns:
+ defer.Deferred[bool], True if the 3PID can be invited, False if not.
+ """
+
+ if self.third_party_rules is None:
+ defer.returnValue(True)
+
+ state_ids = yield self.store.get_filtered_current_state_ids(room_id)
+ room_state_events = yield self.store.get_events(state_ids.values())
+
+ state_events = {}
+ for key, event_id in state_ids.items():
+ state_events[key] = room_state_events[event_id]
+
+ ret = yield self.third_party_rules.check_threepid_can_be_invited(
+ medium, address, state_events,
+ )
+ defer.returnValue(ret)

synapse/handlers/room_member.py

@@ -72,6 +72,7 @@ def __init__(self, hs):
 
  self.clock = hs.get_clock()
  self.spam_checker = hs.get_spam_checker()
+ self.third_party_event_rules = hs.get_third_party_event_rules()
  self._server_notices_mxid = self.config.server_notices_mxid
  self._enable_lookup = hs.config.enable_3pid_lookup
  self.allow_per_room_profiles = self.config.allow_per_room_profiles
@@ -723,6 +724,15 @@ def do_3pid_invite(
  # can't just rely on the standard ratelimiting of events.
  yield self.base_handler.ratelimit(requester)
 
+ can_invite = yield self.third_party_event_rules.check_threepid_can_be_invited(
+ medium, address, room_id,
+ )
+ if not can_invite:
+ raise SynapseError(
+ 403, "This third-party identifier can not be invited in this room",
+ Codes.FORBIDDEN,
+ )
+
  invitee = yield self._lookup_3pid(
  id_server, medium, address
  )