From 6cddf24e361fe43f086307c833cd814dc03363b6 Mon Sep 17 00:00:00 2001 From: Mathieu Velten Date: Sat, 11 Feb 2023 00:31:05 +0100 Subject: [PATCH] Faster joins: don't stall when a user joins during a fast join (#14606) Fixes #12801. Complement tests are at https://github.com/matrix-org/complement/pull/567. Avoid blocking on full state when handling a subsequent join into a partial state room. Also always perform a remote join into partial state rooms, since we do not know whether the joining user has been banned and want to avoid leaking history to banned users. Signed-off-by: Mathieu Velten Co-authored-by: Sean Quah Co-authored-by: David Robertson --- changelog.d/14606.misc | 1 + synapse/api/errors.py | 22 +++++ synapse/federation/federation_server.py | 2 +- synapse/handlers/event_auth.py | 16 +-- synapse/handlers/federation.py | 2 +- synapse/handlers/federation_event.py | 59 ++++++++++-- synapse/handlers/message.py | 2 +- synapse/handlers/room.py | 2 +- synapse/handlers/room_member.py | 118 ++++++++++++++++------- synapse/handlers/room_member_worker.py | 5 +- synapse/storage/databases/main/events.py | 21 +--- tests/handlers/test_federation.py | 40 ++++---- 12 files changed, 196 insertions(+), 94 deletions(-) create mode 100644 changelog.d/14606.misc diff --git a/changelog.d/14606.misc b/changelog.d/14606.misc new file mode 100644 index 0000000000..e2debc96d8 --- /dev/null +++ b/changelog.d/14606.misc @@ -0,0 +1 @@ +Faster joins: don't stall when another user joins during a fast join resync. diff --git a/synapse/api/errors.py b/synapse/api/errors.py index c2c177fd71..9235ce6536 100644 --- a/synapse/api/errors.py +++ b/synapse/api/errors.py @@ -751,3 +751,25 @@ class ModuleFailedException(Exception): Raised when a module API callback fails, for example because it raised an exception. """ + + +class PartialStateConflictError(SynapseError): + """An internal error raised when attempting to persist an event with partial state + after the room containing the event has been un-partial stated. + + This error should be handled by recomputing the event context and trying again. + + This error has an HTTP status code so that it can be transported over replication. + It should not be exposed to clients. + """ + + @staticmethod + def message() -> str: + return "Cannot persist partial state event in un-partial stated room" + + def __init__(self) -> None: + super().__init__( + HTTPStatus.CONFLICT, + msg=PartialStateConflictError.message(), + errcode=Codes.UNKNOWN, + ) diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py index 6addc0bb65..6d99845de5 100644 --- a/synapse/federation/federation_server.py +++ b/synapse/federation/federation_server.py @@ -48,6 +48,7 @@ from synapse.api.errors import ( FederationError, IncompatibleRoomVersionError, NotFoundError, + PartialStateConflictError, SynapseError, UnsupportedRoomVersionError, ) @@ -81,7 +82,6 @@ from synapse.replication.http.federation import ( ReplicationFederationSendEduRestServlet, ReplicationGetQueryRestServlet, ) -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.storage.databases.main.lock import Lock from synapse.storage.databases.main.roommember import extract_heroes_from_room_summary from synapse.storage.roommember import MemberSummary diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py index a23a8ce2a1..46dd63c3f0 100644 --- a/synapse/handlers/event_auth.py +++ b/synapse/handlers/event_auth.py @@ -202,7 +202,7 @@ class EventAuthHandler: state_ids: StateMap[str], room_version: RoomVersion, user_id: str, - prev_member_event: Optional[EventBase], + prev_membership: Optional[str], ) -> None: """ Check whether a user can join a room without an invite due to restricted join rules. @@ -214,15 +214,14 @@ class EventAuthHandler: state_ids: The state of the room as it currently is. room_version: The room version of the room being joined. user_id: The user joining the room. - prev_member_event: The current membership event for this user. + prev_membership: The current membership state for this user. `None` if the + user has never joined the room (equivalent to "leave"). Raises: AuthError if the user cannot join the room. """ # If the member is invited or currently joined, then nothing to do. - if prev_member_event and ( - prev_member_event.membership in (Membership.JOIN, Membership.INVITE) - ): + if prev_membership in (Membership.JOIN, Membership.INVITE): return # This is not a room with a restricted join rule, so we don't need to do the @@ -255,13 +254,14 @@ class EventAuthHandler: ) async def has_restricted_join_rules( - self, state_ids: StateMap[str], room_version: RoomVersion + self, partial_state_ids: StateMap[str], room_version: RoomVersion ) -> bool: """ Return if the room has the proper join rules set for access via rooms. Args: - state_ids: The state of the room as it currently is. + state_ids: The state of the room as it currently is. May be full or partial + state. room_version: The room version of the room to query. Returns: @@ -272,7 +272,7 @@ class EventAuthHandler: return False # If there's no join rule, then it defaults to invite (so this doesn't apply). - join_rules_event_id = state_ids.get((EventTypes.JoinRules, ""), None) + join_rules_event_id = partial_state_ids.get((EventTypes.JoinRules, ""), None) if not join_rules_event_id: return False diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index 43ed4a3dd1..08727e4857 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -49,6 +49,7 @@ from synapse.api.errors import ( FederationPullAttemptBackoffError, HttpResponseException, NotFoundError, + PartialStateConflictError, RequestSendFailed, SynapseError, ) @@ -68,7 +69,6 @@ from synapse.replication.http.federation import ( ReplicationCleanRoomRestServlet, ReplicationStoreRoomOnOutlierMembershipRestServlet, ) -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.storage.databases.main.events_worker import EventRedactBehaviour from synapse.types import JsonDict, StrCollection, get_domain_from_id from synapse.types.state import StateFilter diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py index 3561f2f1de..b7136f8d1c 100644 --- a/synapse/handlers/federation_event.py +++ b/synapse/handlers/federation_event.py @@ -47,6 +47,7 @@ from synapse.api.errors import ( FederationError, FederationPullAttemptBackoffError, HttpResponseException, + PartialStateConflictError, RequestSendFailed, SynapseError, ) @@ -74,7 +75,6 @@ from synapse.replication.http.federation import ( ReplicationFederationSendEventsRestServlet, ) from synapse.state import StateResolutionStore -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.storage.databases.main.events_worker import EventRedactBehaviour from synapse.types import ( PersistedEventPosition, @@ -441,16 +441,17 @@ class FederationEventHandler: # Check if the user is already in the room or invited to the room. user_id = event.state_key prev_member_event_id = prev_state_ids.get((EventTypes.Member, user_id), None) - prev_member_event = None + prev_membership = None if prev_member_event_id: prev_member_event = await self._store.get_event(prev_member_event_id) + prev_membership = prev_member_event.membership # Check if the member should be allowed access via membership in a space. await self._event_auth_handler.check_restricted_join_rules( prev_state_ids, event.room_version, user_id, - prev_member_event, + prev_membership, ) @trace @@ -526,11 +527,57 @@ class FederationEventHandler: "Peristing join-via-remote %s (partial_state: %s)", event, partial_state ) with nested_logging_context(suffix=event.event_id): + if partial_state: + # When handling a second partial state join into a partial state room, + # the returned state will exclude the membership from the first join. To + # preserve prior memberships, we try to compute the partial state before + # the event ourselves if we know about any of the prev events. + # + # When we don't know about any of the prev events, it's fine to just use + # the returned state, since the new join will create a new forward + # extremity, and leave the forward extremity containing our prior + # memberships alone. + prev_event_ids = set(event.prev_event_ids()) + seen_event_ids = await self._store.have_events_in_timeline( + prev_event_ids + ) + missing_event_ids = prev_event_ids - seen_event_ids + + state_maps_to_resolve: List[StateMap[str]] = [] + + # Fetch the state after the prev events that we know about. + state_maps_to_resolve.extend( + ( + await self._state_storage_controller.get_state_groups_ids( + room_id, seen_event_ids, await_full_state=False + ) + ).values() + ) + + # When there are prev events we do not have the state for, we state + # resolve with the state returned by the remote homeserver. + if missing_event_ids or len(state_maps_to_resolve) == 0: + state_maps_to_resolve.append( + {(e.type, e.state_key): e.event_id for e in state} + ) + + state_ids_before_event = ( + await self._state_resolution_handler.resolve_events_with_store( + event.room_id, + room_version.identifier, + state_maps_to_resolve, + event_map=None, + state_res_store=StateResolutionStore(self._store), + ) + ) + else: + state_ids_before_event = { + (e.type, e.state_key): e.event_id for e in state + } + context = await self._state_handler.compute_event_context( event, - state_ids_before_event={ - (e.type, e.state_key): e.event_id for e in state - }, + state_ids_before_event=state_ids_before_event, partial_state=partial_state, ) diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index 3e30f52e4d..8f5b658d9d 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -38,6 +38,7 @@ from synapse.api.errors import ( Codes, ConsentNotGivenError, NotFoundError, + PartialStateConflictError, ShadowBanError, SynapseError, UnstableSpecAuthError, @@ -57,7 +58,6 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background from synapse.metrics.background_process_metrics import run_as_background_process from synapse.replication.http.send_event import ReplicationSendEventRestServlet from synapse.replication.http.send_events import ReplicationSendEventsRestServlet -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.storage.databases.main.events_worker import EventRedactBehaviour from synapse.types import ( MutableStateMap, diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py index 060bbcb181..837dabb3b7 100644 --- a/synapse/handlers/room.py +++ b/synapse/handlers/room.py @@ -43,6 +43,7 @@ from synapse.api.errors import ( Codes, LimitExceededError, NotFoundError, + PartialStateConflictError, StoreError, SynapseError, ) @@ -54,7 +55,6 @@ from synapse.events.utils import copy_and_fixup_power_levels_contents from synapse.handlers.relations import BundledAggregations from synapse.module_api import NOT_SPAM from synapse.rest.admin._base import assert_user_is_admin -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.streams import EventSource from synapse.types import ( JsonDict, diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index 6e7141d2ef..a965c7ec76 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -26,7 +26,13 @@ from synapse.api.constants import ( GuestAccess, Membership, ) -from synapse.api.errors import AuthError, Codes, ShadowBanError, SynapseError +from synapse.api.errors import ( + AuthError, + Codes, + PartialStateConflictError, + ShadowBanError, + SynapseError, +) from synapse.api.ratelimiting import Ratelimiter from synapse.event_auth import get_named_level, get_power_level_event from synapse.events import EventBase @@ -34,7 +40,6 @@ from synapse.events.snapshot import EventContext from synapse.handlers.profile import MAX_AVATAR_URL_LEN, MAX_DISPLAYNAME_LEN from synapse.logging import opentracing from synapse.module_api import NOT_SPAM -from synapse.storage.databases.main.events import PartialStateConflictError from synapse.types import ( JsonDict, Requester, @@ -56,6 +61,13 @@ if TYPE_CHECKING: logger = logging.getLogger(__name__) +class NoKnownServersError(SynapseError): + """No server already resident to the room was provided to the join/knock operation.""" + + def __init__(self, msg: str = "No known servers"): + super().__init__(404, msg) + + class RoomMemberHandler(metaclass=abc.ABCMeta): # TODO(paul): This handler currently contains a messy conflation of # low-level API that works on UserID objects and so on, and REST-level @@ -185,6 +197,10 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): room_id: Room that we are trying to join user: User who is trying to join content: A dict that should be used as the content of the join event. + + Raises: + NoKnownServersError: if remote_room_hosts does not contain a server joined to + the room. """ raise NotImplementedError() @@ -823,14 +839,19 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): latest_event_ids = await self.store.get_prev_events_for_room(room_id) - state_before_join = await self.state_handler.compute_state_after_events( - room_id, latest_event_ids + is_partial_state_room = await self.store.is_partial_state_room(room_id) + partial_state_before_join = await self.state_handler.compute_state_after_events( + room_id, latest_event_ids, await_full_state=False ) + # `is_partial_state_room` also indicates whether `partial_state_before_join` is + # partial. # TODO: Refactor into dictionary of explicitly allowed transitions # between old and new state, with specific error messages for some # transitions and generic otherwise - old_state_id = state_before_join.get((EventTypes.Member, target.to_string())) + old_state_id = partial_state_before_join.get( + (EventTypes.Member, target.to_string()) + ) if old_state_id: old_state = await self.store.get_event(old_state_id, allow_none=True) old_membership = old_state.content.get("membership") if old_state else None @@ -881,11 +902,11 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): if action == "kick": raise AuthError(403, "The target user is not in the room") - is_host_in_room = await self._is_host_in_room(state_before_join) + is_host_in_room = await self._is_host_in_room(partial_state_before_join) if effective_membership_state == Membership.JOIN: if requester.is_guest: - guest_can_join = await self._can_guest_join(state_before_join) + guest_can_join = await self._can_guest_join(partial_state_before_join) if not guest_can_join: # This should be an auth check, but guests are a local concept, # so don't really fit into the general auth process. @@ -927,8 +948,9 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): room_id, remote_room_hosts, content, + is_partial_state_room, is_host_in_room, - state_before_join, + partial_state_before_join, ) if remote_join: if ratelimit: @@ -1073,8 +1095,9 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): room_id: str, remote_room_hosts: List[str], content: JsonDict, + is_partial_state_room: bool, is_host_in_room: bool, - state_before_join: StateMap[str], + partial_state_before_join: StateMap[str], ) -> Tuple[bool, List[str]]: """ Check whether the server should do a remote join (as opposed to a local @@ -1093,9 +1116,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): remote_room_hosts: A list of remote room hosts. content: The content to use as the event body of the join. This may be modified. - is_host_in_room: True if the host is in the room. - state_before_join: The state before the join event (i.e. the resolution of - the states after its parent events). + is_partial_state_room: `True` if the server currently doesn't hold the full + state of the room. + is_host_in_room: `True` if the host is in the room. + partial_state_before_join: The state before the join event (i.e. the + resolution of the states after its parent events). May be full or + partial state, depending on `is_partial_state_room`. Returns: A tuple of: @@ -1109,6 +1135,23 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): if not is_host_in_room: return True, remote_room_hosts + prev_member_event_id = partial_state_before_join.get( + (EventTypes.Member, user_id), None + ) + previous_membership = None + if prev_member_event_id: + prev_member_event = await self.store.get_event(prev_member_event_id) + previous_membership = prev_member_event.membership + + # If we are not fully joined yet, and the target is not already in the room, + # let's do a remote join so another server with the full state can validate + # that the user has not been banned for example. + # We could just accept the join and wait for state res to resolve that later on + # but we would then leak room history to this person until then, which is pretty + # bad. + if is_partial_state_room and previous_membership != Membership.JOIN: + return True, remote_room_hosts + # If the host is in the room, but not one of the authorised hosts # for restricted join rules, a remote join must be used. room_version = await self.store.get_room_version(room_id) @@ -1116,21 +1159,19 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): # If restricted join rules are not being used, a local join can always # be used. if not await self.event_auth_handler.has_restricted_join_rules( - state_before_join, room_version + partial_state_before_join, room_version ): return False, [] # If the user is invited to the room or already joined, the join # event can always be issued locally. - prev_member_event_id = state_before_join.get((EventTypes.Member, user_id), None) - prev_member_event = None - if prev_member_event_id: - prev_member_event = await self.store.get_event(prev_member_event_id) - if prev_member_event.membership in ( - Membership.JOIN, - Membership.INVITE, - ): - return False, [] + if previous_membership in (Membership.JOIN, Membership.INVITE): + return False, [] + + # All the partial state cases are covered above. We have been given the full + # state of the room. + assert not is_partial_state_room + state_before_join = partial_state_before_join # If the local host has a user who can issue invites, then a local # join can be done. @@ -1154,7 +1195,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): # Ensure the member should be allowed access via membership in a room. await self.event_auth_handler.check_restricted_join_rules( - state_before_join, room_version, user_id, prev_member_event + state_before_join, room_version, user_id, previous_membership ) # If this is going to be a local join, additional information must @@ -1304,11 +1345,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): if prev_member_event.membership == Membership.JOIN: await self._user_left_room(target_user, room_id) - async def _can_guest_join(self, current_state_ids: StateMap[str]) -> bool: + async def _can_guest_join(self, partial_current_state_ids: StateMap[str]) -> bool: """ Returns whether a guest can join a room based on its current state. + + Args: + partial_current_state_ids: The current state of the room. May be full or + partial state. """ - guest_access_id = current_state_ids.get((EventTypes.GuestAccess, ""), None) + guest_access_id = partial_current_state_ids.get( + (EventTypes.GuestAccess, ""), None + ) if not guest_access_id: return False @@ -1634,19 +1681,25 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): ) return event, stream_id - async def _is_host_in_room(self, current_state_ids: StateMap[str]) -> bool: + async def _is_host_in_room(self, partial_current_state_ids: StateMap[str]) -> bool: + """Returns whether the homeserver is in the room based on its current state. + + Args: + partial_current_state_ids: The current state of the room. May be full or + partial state. + """ # Have we just created the room, and is this about to be the very # first member event? - create_event_id = current_state_ids.get(("m.room.create", "")) - if len(current_state_ids) == 1 and create_event_id: + create_event_id = partial_current_state_ids.get(("m.room.create", "")) + if len(partial_current_state_ids) == 1 and create_event_id: # We can only get here if we're in the process of creating the room return True - for etype, state_key in current_state_ids: + for etype, state_key in partial_current_state_ids: if etype != EventTypes.Member or not self.hs.is_mine_id(state_key): continue - event_id = current_state_ids[(etype, state_key)] + event_id = partial_current_state_ids[(etype, state_key)] event = await self.store.get_event(event_id, allow_none=True) if not event: continue @@ -1715,8 +1768,7 @@ class RoomMemberMasterHandler(RoomMemberHandler): ] if len(remote_room_hosts) == 0: - raise SynapseError( - 404, + raise NoKnownServersError( "Can't join remote room because no servers " "that are in the room have been provided.", ) @@ -1947,7 +1999,7 @@ class RoomMemberMasterHandler(RoomMemberHandler): ] if len(remote_room_hosts) == 0: - raise SynapseError(404, "No known servers") + raise NoKnownServersError() return await self.federation_handler.do_knock( remote_room_hosts, room_id, user.to_string(), content=content diff --git a/synapse/handlers/room_member_worker.py b/synapse/handlers/room_member_worker.py index 221552a2a6..ba261702d4 100644 --- a/synapse/handlers/room_member_worker.py +++ b/synapse/handlers/room_member_worker.py @@ -15,8 +15,7 @@ import logging from typing import TYPE_CHECKING, List, Optional, Tuple -from synapse.api.errors import SynapseError -from synapse.handlers.room_member import RoomMemberHandler +from synapse.handlers.room_member import NoKnownServersError, RoomMemberHandler from synapse.replication.http.membership import ( ReplicationRemoteJoinRestServlet as ReplRemoteJoin, ReplicationRemoteKnockRestServlet as ReplRemoteKnock, @@ -52,7 +51,7 @@ class RoomMemberWorkerHandler(RoomMemberHandler): ) -> Tuple[str, int]: """Implements RoomMemberHandler._remote_join""" if len(remote_room_hosts) == 0: - raise SynapseError(404, "No known servers") + raise NoKnownServersError() ret = await self._remote_join_client( requester=requester, diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py index cb66376fb4..ffe766fd56 100644 --- a/synapse/storage/databases/main/events.py +++ b/synapse/storage/databases/main/events.py @@ -16,7 +16,6 @@ import itertools import logging from collections import OrderedDict -from http import HTTPStatus from typing import ( TYPE_CHECKING, Any, @@ -36,7 +35,7 @@ from prometheus_client import Counter import synapse.metrics from synapse.api.constants import EventContentFields, EventTypes, RelationTypes -from synapse.api.errors import Codes, SynapseError +from synapse.api.errors import PartialStateConflictError from synapse.api.room_versions import RoomVersions from synapse.events import EventBase, relation_from_event from synapse.events.snapshot import EventContext @@ -72,24 +71,6 @@ event_counter = Counter( ) -class PartialStateConflictError(SynapseError): - """An internal error raised when attempting to persist an event with partial state - after the room containing the event has been un-partial stated. - - This error should be handled by recomputing the event context and trying again. - - This error has an HTTP status code so that it can be transported over replication. - It should not be exposed to clients. - """ - - def __init__(self) -> None: - super().__init__( - HTTPStatus.CONFLICT, - msg="Cannot persist partial state event in un-partial stated room", - errcode=Codes.UNKNOWN, - ) - - @attr.s(slots=True, auto_attribs=True) class DeltaState: """Deltas to use to update the `current_state_events` table. diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py index 57675fa407..5868eb2da7 100644 --- a/tests/handlers/test_federation.py +++ b/tests/handlers/test_federation.py @@ -575,26 +575,6 @@ class PartialJoinTestCase(unittest.FederatingHomeserverTestCase): fed_client = fed_handler.federation_client room_id = "!room:example.com" - membership_event = make_event_from_dict( - { - "room_id": room_id, - "type": "m.room.member", - "sender": "@alice:test", - "state_key": "@alice:test", - "content": {"membership": "join"}, - }, - RoomVersions.V10, - ) - - mock_make_membership_event = Mock( - return_value=make_awaitable( - ( - "example.com", - membership_event, - RoomVersions.V10, - ) - ) - ) EVENT_CREATE = make_event_from_dict( { @@ -640,6 +620,26 @@ class PartialJoinTestCase(unittest.FederatingHomeserverTestCase): }, room_version=RoomVersions.V10, ) + membership_event = make_event_from_dict( + { + "room_id": room_id, + "type": "m.room.member", + "sender": "@alice:test", + "state_key": "@alice:test", + "content": {"membership": "join"}, + "prev_events": [EVENT_INVITATION_MEMBERSHIP.event_id], + }, + RoomVersions.V10, + ) + mock_make_membership_event = Mock( + return_value=make_awaitable( + ( + "example.com", + membership_event, + RoomVersions.V10, + ) + ) + ) mock_send_join = Mock( return_value=make_awaitable( SendJoinResult(