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authorAndrew Morgan <1342360+anoadragon453@users.noreply.github.com>2021-02-09 19:07:00 +0000
committerGitHub <noreply@github.com>2021-02-09 19:07:00 +0000
commit6bf58d8194ff7c89a1c8249bade78492bbfa0900 (patch)
treedbaccc690b25f7273562569ba25b09c8a0a90b0b /synapse/handlers/federation.py
parentAdd complement running monolith synapse to buildkite pipeline (#80) (diff)
downloadsynapse-6bf58d8194ff7c89a1c8249bade78492bbfa0900.tar.xz
Add knocking support (#81)
Implement knocking as defined by https://github.com/matrix-org/matrix-doc/pull/2403

This is the base knocking stuff, taken from https://github.com/matrix-org/synapse/pull/6739
and does not include any public room directory changes.

While knocking hasn't merged yet on mainline due to waiting on getting Complement
into Synapse's CI, the code has been well-tested.
Diffstat (limited to 'synapse/handlers/federation.py')
-rw-r--r--synapse/handlers/federation.py179
1 files changed, 178 insertions, 1 deletions
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py

index f27dd84213..a9ac4bd85e 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py
@@ -1,7 +1,8 @@ # -*- coding: utf-8 -*- # Copyright 2014-2016 OpenMarket Ltd # Copyright 2017-2018 New Vector Ltd -# Copyright 2019 The Matrix.org Foundation C.I.C. +# Copyright 2019-2020 The Matrix.org Foundation C.I.C. +# Copyright 2020 Sorunome # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. @@ -1442,6 +1443,69 @@ class FederationHandler(BaseHandler): run_in_background(self._handle_queued_pdus, room_queue) + @log_function + async def do_knock( + self, target_hosts: List[str], room_id: str, knockee: str, content: JsonDict, + ) -> Tuple[str, int]: + """Sends the knock to the remote server. + + This first triggers a make_knock request that returns a partial + event that we can fill out and sign. This is then sent to the + remote server via send_knock. + + Knock events must be signed by the knockee's server before distributing. + + Args: + target_hosts: A list of hosts that we want to try knocking through. + room_id: The ID of the room to knock on. + knockee: The ID of the user who is knocking. + content: The content of the knock event. + + Returns: + A tuple of (event ID, stream ID). + + Raises: + SynapseError: If the chosen remote server returns a 3xx/4xx code. + RuntimeError: If no servers were reachable. + """ + logger.debug("Knocking on room %s on behalf of user %s", room_id, knockee) + + # Ask the remote server to create a valid knock event for us. Once received, + # we sign the event + origin, event, event_format_version = await self._make_and_verify_event( + target_hosts, room_id, knockee, Membership.KNOCK, content, + ) + + # Record the room ID and its version so that we have a record of the room + await self._maybe_store_room_on_outlier_membership( + room_id=event.room_id, room_version=event_format_version + ) + + # Initially try the host that we successfully called /make_knock on + try: + target_hosts.remove(origin) + target_hosts.insert(0, origin) + except ValueError: + pass + + # Send the signed event back to the room, and potentially receive some + # further information about the room in the form of partial state events + stripped_room_state = await self.federation_client.send_knock( + target_hosts, event + ) + + # Store any stripped room state events in the "unsigned" key of the event. + # This is a bit of a hack and is cribbing off of invites. Basically we + # store the room state here and retrieve it again when this event appears + # in the invitee's sync stream. It is stripped out for all other local users. + event.unsigned["knock_room_state"] = stripped_room_state["knock_state_events"] + + context = await self.state_handler.compute_event_context(event) + stream_id = await self.persist_events_and_notify( + event.room_id, [(event, context)] + ) + return event.event_id, stream_id + async def _handle_queued_pdus(self, room_queue): """Process PDUs which got queued up while we were busy send_joining. @@ -1785,6 +1849,119 @@ class FederationHandler(BaseHandler): return None + @log_function + async def on_make_knock_request( + self, origin: str, room_id: str, user_id: str + ) -> EventBase: + """We've received a make_knock request, so we create a partial + knock event for the room and return that. We do *not* persist or + process it until the other server has signed it and sent it back. + + Args: + origin: The (verified) server name of the requesting server. + room_id: The room to create the knock event in. + user_id: The user to create the knock for. + + Returns: + The partial knock event. + """ + if get_domain_from_id(user_id) != origin: + logger.info( + "Get /xyz.amorgan.knock/make_knock request for user %r" + "from different origin %s, ignoring", + user_id, + origin, + ) + raise SynapseError(403, "User not from origin", Codes.FORBIDDEN) + + room_version = await self.store.get_room_version_id(room_id) + builder = self.event_builder_factory.new( + room_version, + { + "type": EventTypes.Member, + "content": {"membership": Membership.KNOCK}, + "room_id": room_id, + "sender": user_id, + "state_key": user_id, + }, + ) + + event, context = await self.event_creation_handler.create_new_client_event( + builder=builder + ) + + event_allowed = await self.third_party_event_rules.check_event_allowed( + event, context + ) + if not event_allowed: + logger.warning("Creation of knock %s forbidden by third-party rules", event) + raise SynapseError( + 403, "This event is not allowed in this context", Codes.FORBIDDEN + ) + + try: + # The remote hasn't signed it yet, obviously. We'll do the full checks + # when we get the event back in `on_send_knock_request` + await self.auth.check_from_context( + room_version, event, context, do_sig_check=False + ) + except AuthError as e: + logger.warning("Failed to create new knock %r because %s", event, e) + raise e + + return event + + @log_function + async def on_send_knock_request( + self, origin: str, event: EventBase + ) -> EventContext: + """ + We have received a knock event for a room. Verify that event and send it into the room + on the knocking homeserver's behalf. + + Args: + origin: The remote homeserver of the knocking user. + event: The knocking member event that has been signed by the remote homeserver. + + Returns: + The context of the event after inserting it into the room graph. + """ + logger.debug( + "on_send_knock_request: Got event: %s, signatures: %s", + event.event_id, + event.signatures, + ) + + if get_domain_from_id(event.sender) != origin: + logger.info( + "Got /xyz.amorgan.knock/send_knock request for user %r " + "from different origin %s", + event.sender, + origin, + ) + raise SynapseError(403, "User not from origin", Codes.FORBIDDEN) + + event.internal_metadata.outlier = False + + context = await self._handle_new_event(origin, event) + + event_allowed = await self.third_party_event_rules.check_event_allowed( + event, context + ) + if not event_allowed: + logger.info("Sending of knock %s forbidden by third-party rules", event) + raise SynapseError( + 403, "This event is not allowed in this context", Codes.FORBIDDEN + ) + + logger.debug( + "on_send_knock_request: After _handle_new_event: %s, sigs: %s", + event.event_id, + event.signatures, + ) + + return context + async def get_state_for_pdu(self, room_id: str, event_id: str) -> List[EventBase]: """Returns the state at the event. i.e. not including said event. """