diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index e23503c1e0..360a50cc71 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -15,11 +15,12 @@
import logging
import typing
-from typing import Any, Dict, Iterable, List, Optional, Set, Tuple, Union
+from typing import Any, Collection, Dict, Iterable, List, Optional, Set, Tuple, Union
from canonicaljson import encode_canonical_json
from signedjson.key import decode_verify_key_bytes
from signedjson.sign import SignatureVerifyException, verify_signed_json
+from typing_extensions import Protocol
from unpaddedbase64 import decode_base64
from synapse.api.constants import (
@@ -35,7 +36,8 @@ from synapse.api.room_versions import (
EventFormatVersions,
RoomVersion,
)
-from synapse.types import StateMap, UserID, get_domain_from_id
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
+from synapse.types import MutableStateMap, StateMap, UserID, get_domain_from_id
if typing.TYPE_CHECKING:
# conditional imports to avoid import cycle
@@ -45,6 +47,17 @@ if typing.TYPE_CHECKING:
logger = logging.getLogger(__name__)
+class _EventSourceStore(Protocol):
+ async def get_events(
+ self,
+ event_ids: Collection[str],
+ redact_behaviour: EventRedactBehaviour,
+ get_prev_content: bool = False,
+ allow_rejected: bool = False,
+ ) -> Dict[str, "EventBase"]:
+ ...
+
+
def validate_event_for_room_version(event: "EventBase") -> None:
"""Ensure that the event complies with the limits, and has the right signatures
@@ -112,47 +125,52 @@ def validate_event_for_room_version(event: "EventBase") -> None:
raise AuthError(403, "Event not signed by authorising server")
-def check_auth_rules_for_event(
+async def check_state_independent_auth_rules(
+ store: _EventSourceStore,
event: "EventBase",
- auth_events: Iterable["EventBase"],
) -> None:
- """Check that an event complies with the auth rules
-
- Checks whether an event passes the auth rules with a given set of state events
-
- Assumes that we have already checked that the event is the right shape (it has
- enough signatures, has a room ID, etc). In other words:
-
- - it's fine for use in state resolution, when we have already decided whether to
- accept the event or not, and are now trying to decide whether it should make it
- into the room state
+ """Check that an event complies with auth rules that are independent of room state
- - when we're doing the initial event auth, it is only suitable in combination with
- a bunch of other tests.
+ Runs through the first few auth rules, which are independent of room state. (Which
+ means that we only need to them once for each received event)
Args:
+ store: the datastore; used to fetch the auth events for validation
event: the event being checked.
- auth_events: the room state to check the events against.
Raises:
AuthError if the checks fail
"""
- # We need to ensure that the auth events are actually for the same room, to
- # stop people from using powers they've been granted in other rooms for
- # example.
- #
- # Arguably we don't need to do this when we're just doing state res, as presumably
- # the state res algorithm isn't silly enough to give us events from different rooms.
- # Still, it's easier to do it anyway.
+ # Check the auth events.
+ auth_events = await store.get_events(
+ event.auth_event_ids(),
+ redact_behaviour=EventRedactBehaviour.as_is,
+ allow_rejected=True,
+ )
room_id = event.room_id
- for auth_event in auth_events:
+ auth_dict: MutableStateMap[str] = {}
+ for auth_event_id in event.auth_event_ids():
+ auth_event = auth_events.get(auth_event_id)
+
+ # we should have all the auth events by now, so if we do not, that suggests
+ # a synapse programming error
+ if auth_event is None:
+ raise RuntimeError(
+ f"Event {event.event_id} has unknown auth event {auth_event_id}"
+ )
+
+ # We need to ensure that the auth events are actually for the same room, to
+ # stop people from using powers they've been granted in other rooms for
+ # example.
if auth_event.room_id != room_id:
raise AuthError(
403,
"During auth for event %s in room %s, found event %s in the state "
"which is in room %s"
- % (event.event_id, room_id, auth_event.event_id, auth_event.room_id),
+ % (event.event_id, room_id, auth_event_id, auth_event.room_id),
)
+
+ # We also need to check that the auth event itself is not rejected.
if auth_event.rejected_reason:
raise AuthError(
403,
@@ -160,6 +178,8 @@ def check_auth_rules_for_event(
% (event.event_id, auth_event.event_id),
)
+ auth_dict[(auth_event.type, auth_event.state_key)] = auth_event_id
+
# Implementation of https://matrix.org/docs/spec/rooms/v1#authorization-rules
#
# 1. If type is m.room.create:
@@ -181,16 +201,46 @@ def check_auth_rules_for_event(
"room appears to have unsupported version %s" % (room_version_prop,),
)
- logger.debug("Allowing! %s", event)
return
- auth_dict = {(e.type, e.state_key): e for e in auth_events}
-
# 3. If event does not have a m.room.create in its auth_events, reject.
creation_event = auth_dict.get((EventTypes.Create, ""), None)
if not creation_event:
raise AuthError(403, "No create event in auth events")
+
+def check_state_dependent_auth_rules(
+ event: "EventBase",
+ auth_events: Iterable["EventBase"],
+) -> None:
+ """Check that an event complies with auth rules that depend on room state
+
+ Runs through the parts of the auth rules that check an event against bits of room
+ state.
+
+ Note:
+
+ - it's fine for use in state resolution, when we have already decided whether to
+ accept the event or not, and are now trying to decide whether it should make it
+ into the room state
+
+ - when we're doing the initial event auth, it is only suitable in combination with
+ a bunch of other tests (including, but not limited to, check_state_independent_auth_rules).
+
+ Args:
+ event: the event being checked.
+ auth_events: the room state to check the events against.
+
+ Raises:
+ AuthError if the checks fail
+ """
+ # there are no state-dependent auth rules for create events.
+ if event.type == EventTypes.Create:
+ logger.debug("Allowing! %s", event)
+ return
+
+ auth_dict = {(e.type, e.state_key): e for e in auth_events}
+
# additional check for m.federate
creating_domain = get_domain_from_id(event.room_id)
originating_domain = get_domain_from_id(event.sender)
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