From 7709d2bd167e27493b134e938410c307f8c10396 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 28 Jan 2019 21:09:45 +0000 Subject: [PATCH] Implement rechecking of redactions --- synapse/api/auth.py | 4 ++-- synapse/event_auth.py | 24 ++++++++++++++++++------ synapse/events/__init__.py | 3 +++ synapse/handlers/message.py | 6 +++++- synapse/storage/events_worker.py | 26 +++++++++++++++++++++++++- 5 files changed, 53 insertions(+), 10 deletions(-) diff --git a/synapse/api/auth.py b/synapse/api/auth.py index 7b213e54c..963e0e7d6 100644 --- a/synapse/api/auth.py +++ b/synapse/api/auth.py @@ -627,7 +627,7 @@ class Auth(object): defer.returnValue(auth_ids) - def check_redaction(self, event, auth_events): + def check_redaction(self, room_version, event, auth_events): """Check whether the event sender is allowed to redact the target event. Returns: @@ -640,7 +640,7 @@ class Auth(object): AuthError if the event sender is definitely not allowed to redact the target event. """ - return event_auth.check_redaction(event, auth_events) + return event_auth.check_redaction(room_version, event, auth_events) @defer.inlineCallbacks def check_can_change_room_list(self, room_id, user): diff --git a/synapse/event_auth.py b/synapse/event_auth.py index 9adedbbb0..a95d142f0 100644 --- a/synapse/event_auth.py +++ b/synapse/event_auth.py @@ -20,7 +20,13 @@ from signedjson.key import decode_verify_key_bytes from signedjson.sign import SignatureVerifyException, verify_signed_json from unpaddedbase64 import decode_base64 -from synapse.api.constants import KNOWN_ROOM_VERSIONS, EventTypes, JoinRules, Membership +from synapse.api.constants import ( + KNOWN_ROOM_VERSIONS, + EventTypes, + JoinRules, + Membership, + RoomVersions, +) from synapse.api.errors import AuthError, EventSizeError, SynapseError from synapse.types import UserID, get_domain_from_id @@ -168,7 +174,7 @@ def check(room_version, event, auth_events, do_sig_check=True, do_size_check=Tru _check_power_levels(event, auth_events) if event.type == EventTypes.Redaction: - check_redaction(event, auth_events) + check_redaction(room_version, event, auth_events) logger.debug("Allowing! %s", event) @@ -422,7 +428,7 @@ def _can_send_event(event, auth_events): return True -def check_redaction(event, auth_events): +def check_redaction(room_version, event, auth_events): """Check whether the event sender is allowed to redact the target event. Returns: @@ -442,10 +448,16 @@ def check_redaction(event, auth_events): if user_level >= redact_level: return False - redacter_domain = get_domain_from_id(event.event_id) - redactee_domain = get_domain_from_id(event.redacts) - if redacter_domain == redactee_domain: + if room_version in (RoomVersions.V1, RoomVersions.V2, RoomVersions.VDH_TEST): + redacter_domain = get_domain_from_id(event.event_id) + redactee_domain = get_domain_from_id(event.redacts) + if redacter_domain == redactee_domain: + return True + elif room_version == RoomVersions.V3: + event.internal_metadata.recheck_redaction = True return True + else: + raise RuntimeError("Unrecognized room version %r" % (room_version,)) raise AuthError( 403, diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py index 3fe52aaa4..70d3c0fbd 100644 --- a/synapse/events/__init__.py +++ b/synapse/events/__init__.py @@ -63,6 +63,9 @@ class _EventInternalMetadata(object): """ return getattr(self, "send_on_behalf_of", None) + def need_to_check_redaction(self): + return getattr(self, "recheck_redaction", False) + def _event_dict_property(key): # We want to be able to use hasattr with the event dict properties. diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index 05d1370c1..0cfced43d 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -767,7 +767,8 @@ class EventCreationHandler(object): auth_events = { (e.type, e.state_key): e for e in auth_events.values() } - if self.auth.check_redaction(event, auth_events=auth_events): + room_version = yield self.store.get_room_version(event.room_id) + if self.auth.check_redaction(room_version, event, auth_events=auth_events): original_event = yield self.store.get_event( event.redacts, check_redacted=False, @@ -781,6 +782,9 @@ class EventCreationHandler(object): "You don't have permission to redact events" ) + # We've already checked. + event.internal_metadata.recheck_redaction = False + if event.type == EventTypes.Create: prev_state_ids = yield context.get_prev_state_ids(self.store) if prev_state_ids: diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py index 0a0ca58fc..9ce19430e 100644 --- a/synapse/storage/events_worker.py +++ b/synapse/storage/events_worker.py @@ -21,13 +21,14 @@ from canonicaljson import json from twisted.internet import defer -from synapse.api.constants import EventFormatVersions +from synapse.api.constants import EventFormatVersions, EventTypes from synapse.api.errors import NotFoundError from synapse.events import FrozenEvent, event_type_from_format_version # noqa: F401 # these are only included to make the type annotations work from synapse.events.snapshot import EventContext # noqa: F401 from synapse.events.utils import prune_event from synapse.metrics.background_process_metrics import run_as_background_process +from synapse.types import get_domain_from_id from synapse.util.logcontext import ( LoggingContext, PreserveLoggingContext, @@ -174,6 +175,29 @@ class EventsWorkerStore(SQLBaseStore): if not entry: continue + # Some redactions in room version v3 need to be rechecked if we + # didn't have the redacted event at the time, so we recheck on read + # instead. + if not allow_rejected and entry.event.type == EventTypes.Redaction: + if entry.event.internal_metadata.need_to_check_redaction(): + orig = yield self.get_event( + entry.event.redacts, + allow_none=True, + allow_rejected=True, + get_prev_content=False, + ) + expected_domain = get_domain_from_id(entry.event.sender) + if orig and get_domain_from_id(orig.sender) == expected_domain: + # This redaction event is allowed. Mark as not needing a + # recheck. + entry.event.recheck_redaction = False + else: + # We don't have the event that is being redacted, so we + # assume that the event isn't authorized for now. (If we + # later receive the event, then we will always redact + # it anyway, since we have this redaction) + continue + if allow_rejected or not entry.event.rejected_reason: if check_redacted and entry.redacted_event: event = entry.redacted_event