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Fix bug in device list caching when remote users leave rooms #13749

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merged 8 commits into from
Sep 14, 2022
Merged

Fix bug in device list caching when remote users leave rooms #13749

merged 8 commits into from
Sep 14, 2022

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squahtx
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@squahtx squahtx commented Sep 8, 2022 •
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When a remote user leaves the last room shared with the homeserver, we
have to mark their device list as unsubscribed, otherwise we would hold
on to a stale device list in our cache. Crucially, the device list would
remain cached even after the remote user rejoined the room, which could
lead to E2EE failures until the next change to the remote user's device
list.

Fixes #13651.

Signed-off-by: Sean Quah seanq@matrix.org

Complement tests: matrix-org/complement#459

Sean Quah added 3 commits September 8, 2022 14:01
Fix bug in device list caching when remote users leave rooms
18e5f60 
When a remote user leaves the last room shared with the homeserver, we
have to mark their device list as unsubscribed, otherwise we will hold
on to a stale device list in our cache. Crucially, the device list will
remain cached even after the remote user rejoins the room, which can
lead to E2EE failures until the remote user's device list next changes.

Signed-off-by: Sean Quah <seanq@matrix.org>
Remove redundant mark_remote_user_device_list_as_unsubscribed call
766b136 
Now that we are handling device list unsubscriptions in the event
persistence code, it's no longer necessary to mark device lists as
unsubscribed elsewhere.
Check whether we still share a room when using cached device lists
17dd441 
Signed-off-by: Sean Quah <seanq@matrix.org>
@squahtx squahtx requested a review from a team as a code owner September 8, 2022 13:06
squahtx
squahtx commented Sep 8, 2022
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synapse/handlers/e2e_keys.py Outdated
Comment on lines 178 to 204

# Check that the homeserver still shares a room with all cached users.
# Note that this check may be slightly racy when a remote user leaves a
# room after we have fetched their cached device list. In the worst case
# we will do extra federation queries for devices that we had cached.
cached_users = set(remote_results.keys())
valid_cached_users = (
await self.store.get_users_server_still_shares_room_with(
remote_results.keys()
)
)
invalid_cached_users = cached_users - valid_cached_users
if invalid_cached_users:
# Fix up results. If we get here there may be bugs in device list
# tracking.
# TODO: is this actually useful? it doesn't fix the case where a
# remote user rejoins a room and we query their device list
# after.
user_ids_not_in_cache.update(invalid_cached_users)
for invalid_user_id in invalid_cached_users:
remote_results.pop(invalid_user_id)
logger.error(
"Devices for %s were cached, but the server no longer shares "
"any rooms with them. The cached device lists are stale.",
invalid_cached_users,
)

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I'm not fully convinced this check is useful, because it'll only catch /keys/query requests done while we no longer share a room with a remote user, which I wouldn't expect to happen often, or at all.

It's also slightly racy and can trigger spuriously when a remote user leaves a room while we're in the middle of handling the request.

Do we want to keep it or remove it?

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I think its valid for clients to do a /keys/query for users they don't share a room with, e.g. because they're about to start a DM or something?

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That sounds plausible!

squahtx
squahtx commented Sep 8, 2022
View reviewed changes
synapse/storage/controllers/persist_events.py
user_id
for event_type, user_id in delta.to_delete
if event_type == EventTypes.Member
and not self.is_mine_id(user_id)
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Needs #13746, otherwise we can raise errors when there are malformed user IDs in the room state.

@squahtx squahtx mentioned this pull request Sep 8, 2022
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@squahtx squahtx marked this pull request as draft September 8, 2022 14:41
@squahtx squahtx force-pushed the squah/fix_remote_user_leave_device_list_tracking branch from 4b2a14b to 5a12cb7 Compare September 8, 2022 14:54
erikjohnston
erikjohnston reviewed Sep 9, 2022
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I think this looks good, other than I don't think we want to log an error?

squahtx
squahtx commented Sep 9, 2022
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synapse/handlers/e2e_keys.py Outdated Show resolved Hide resolved
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squahtx commented Sep 9, 2022

I think this looks good, other than I don't think we want to log an error?

Do we not want sentry issues when we discover we've cached a device list we shouldn't have?

@squahtx squahtx marked this pull request as ready for review September 9, 2022 13:27
@squahtx squahtx mentioned this pull request Sep 9, 2022
Merged
@squahtx squahtx merged commit c737744 into develop Sep 14, 2022
@squahtx squahtx deleted the squah/fix_remote_user_leave_device_list_tracking branch September 14, 2022 09:42
@DMRobertson DMRobertson mentioned this pull request Sep 14, 2022
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squahtx added a commit that referenced this pull request Sep 16, 2022
@squahtx
Remove error spam when users query the keys of departed remote users (#…
d64e851 
…13826)

The error message introduced in #13749 has turned out to be very spammy.
Remove it for now.
Fizzadar added a commit to beeper/synapse-legacy-fork that referenced this pull request Sep 30, 2022
@Fizzadar
Merge tag 'v1.68.0' into beeper
c5bdd1e 
Synapse 1.68.0 (2022-09-27)
===========================

Please note that Synapse will now refuse to start if configured to use a version of SQLite older than 3.27.

In addition, please note that installing Synapse from a source checkout now requires a recent Rust compiler.
Those using packages will not be affected. On most platforms, installing with `pip install matrix-synapse` will not be affected.
See the [upgrade notes](https://matrix-org.github.io/synapse/v1.68/upgrade.html#upgrading-to-v1680).

Bugfixes
--------

- Fix packaging to include `Cargo.lock` in `sdist`. ([\matrix-org#13909](matrix-org#13909))

Synapse 1.68.0rc2 (2022-09-23)
==============================

Bugfixes
--------

- Fix building from packaged sdist. Broken in v1.68.0rc1. ([\matrix-org#13866](matrix-org#13866))

Internal Changes
----------------

- Fix the release script not publishing binary wheels. ([\matrix-org#13850](matrix-org#13850))
- Lower minimum supported rustc version to 1.58.1. ([\matrix-org#13857](matrix-org#13857))
- Lock Rust dependencies' versions. ([\matrix-org#13858](matrix-org#13858))

Synapse 1.68.0rc1 (2022-09-20)
==============================

Features
--------

- Keep track of when we fail to process a pulled event over federation so we can intelligently back off in the future. ([\matrix-org#13589](matrix-org#13589), [\matrix-org#13814](matrix-org#13814))
- Add an [admin API endpoint to fetch messages within a particular window of time](https://matrix-org.github.io/synapse/v1.68/admin_api/rooms.html#room-messages-api). ([\matrix-org#13672](matrix-org#13672))
- Add an [admin API endpoint to find a user based on their external ID in an auth provider](https://matrix-org.github.io/synapse/v1.68/admin_api/user_admin_api.html#find-a-user-based-on-their-id-in-an-auth-provider). ([\matrix-org#13810](matrix-org#13810))
- Cancel the processing of key query requests when they time out. ([\matrix-org#13680](matrix-org#13680))
- Improve validation of request bodies for the following client-server API endpoints: [`/account/3pid/msisdn/requestToken`](https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3account3pidmsisdnrequesttoken), [`/org.matrix.msc3720/account_status`](https://github.com/matrix-org/matrix-spec-proposals/blob/babolivier/user_status/proposals/3720-account-status.md#post-_matrixclientv1account_status), [`/account/3pid/add`](https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3account3pidadd), [`/account/3pid/bind`](https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3account3pidbind), [`/account/3pid/delete`](https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3account3piddelete) and [`/account/3pid/unbind`](https://spec.matrix.org/v1.3/client-server-api/#post_matrixclientv3account3pidunbind). ([\matrix-org#13687](matrix-org#13687), [\matrix-org#13736](matrix-org#13736))
- Document the timestamp when a user accepts the consent, if [consent tracking](https://matrix-org.github.io/synapse/latest/consent_tracking.html) is used. ([\matrix-org#13741](matrix-org#13741))
- Add a `listeners[x].request_id_header` configuration option to specify which request header to extract and use as the request ID in order to correlate requests from a reverse proxy. ([\matrix-org#13801](matrix-org#13801))

Bugfixes
--------

- Fix a bug introduced in Synapse 1.41.0 where the `/hierarchy` API returned non-standard information (a `room_id` field under each entry in `children_state`). ([\matrix-org#13506](matrix-org#13506))
- Fix a long-standing bug where previously rejected events could end up in room state because they pass auth checks given the current state of the room. ([\matrix-org#13723](matrix-org#13723))
- Fix a long-standing bug where Synapse fails to start if a signing key file contains an empty line. ([\matrix-org#13738](matrix-org#13738))
- Fix a long-standing bug where Synapse would fail to handle malformed user IDs or room aliases gracefully in certain cases. ([\matrix-org#13746](matrix-org#13746))
- Fix a long-standing bug where device lists would remain cached when remote users left and rejoined the last room shared with the local homeserver. ([\matrix-org#13749](matrix-org#13749), [\matrix-org#13826](matrix-org#13826))
- Fix a long-standing bug that could cause stale caches in some rare cases on the first startup of Synapse with replication. ([\matrix-org#13766](matrix-org#13766))
- Fix a long-standing spec compliance bug where Synapse would accept a trailing slash on the end of `/get_missing_events` federation requests. ([\matrix-org#13789](matrix-org#13789))
- Delete associated data from `event_failed_pull_attempts`, `insertion_events`, `insertion_event_extremities`, `insertion_event_extremities`, `insertion_event_extremities` when purging the room. ([\matrix-org#13825](matrix-org#13825))

Improved Documentation
----------------------

- Note that `libpq` is required on ARM-based Macs. ([\matrix-org#13480](matrix-org#13480))
- Fix a mistake in the config manual introduced in Synapse 1.22.0: the `event_cache_size` _is_ scaled by `caches.global_factor`. ([\matrix-org#13726](matrix-org#13726))
- Fix a typo in the documentation for the login ratelimiting configuration. ([\matrix-org#13727](matrix-org#13727))
- Define Synapse's compatability policy for SQLite versions. ([\matrix-org#13728](matrix-org#13728))
- Add docs for the common fix of deleting the `matrix_synapse.egg-info/` directory for fixing Python dependency problems. ([\matrix-org#13785](matrix-org#13785))
- Update request log format documentation to mention the format used when the authenticated user is controlling another user. ([\matrix-org#13794](matrix-org#13794))

Deprecations and Removals
-------------------------

- Synapse will now refuse to start if configured to use SQLite < 3.27. ([\matrix-org#13760](matrix-org#13760))
- Don't include redundant `prev_state` in new events. Contributed by Denis Kariakin (@dakariakin). ([\matrix-org#13791](matrix-org#13791))

Internal Changes
----------------

- Add a stub Rust crate. ([\matrix-org#12595](matrix-org#12595), [\matrix-org#13734](matrix-org#13734), [\matrix-org#13735](matrix-org#13735), [\matrix-org#13743](matrix-org#13743), [\matrix-org#13763](matrix-org#13763), [\matrix-org#13769](matrix-org#13769), [\matrix-org#13778](matrix-org#13778))
- Bump the minimum dependency of `matrix_common` to 1.3.0 to make use of the `MXCUri` class. Use `MXCUri` to simplify media retention test code. ([\matrix-org#13162](matrix-org#13162))
- Add and populate the `event_stream_ordering` column on the `receipts` table for future optimisation of push action processing. Contributed by Nick @ Beeper (@Fizzadar). ([\matrix-org#13703](matrix-org#13703))
- Rename the `EventFormatVersions` enum values so that they line up with room version numbers. ([\matrix-org#13706](matrix-org#13706))
- Update trial old deps CI to use Poetry 1.2.0. ([\matrix-org#13707](matrix-org#13707), [\matrix-org#13725](matrix-org#13725))
- Add experimental configuration option to allow disabling legacy Prometheus metric names. ([\matrix-org#13714](matrix-org#13714), [\matrix-org#13717](matrix-org#13717), [\matrix-org#13718](matrix-org#13718))
- Fix typechecking with latest types-jsonschema. ([\matrix-org#13724](matrix-org#13724))
- Strip number suffix from instance name to consolidate services that traces are spread over. ([\matrix-org#13729](matrix-org#13729))
- Instrument `get_metadata_for_events` for understandable traces in Jaeger. ([\matrix-org#13730](matrix-org#13730))
- Remove old queries to join room memberships to current state events. Contributed by Nick @ Beeper (@Fizzadar). ([\matrix-org#13745](matrix-org#13745))
- Avoid raising an error due to malformed user IDs in `get_current_hosts_in_room`. Malformed user IDs cannot currently join a room, so this error would not be hit. ([\matrix-org#13748](matrix-org#13748))
- Update the docstrings for `get_users_in_room` and `get_current_hosts_in_room` to explain the impact of partial state. ([\matrix-org#13750](matrix-org#13750))
- Use an additional database query when persisting receipts. ([\matrix-org#13752](matrix-org#13752))
- Preparatory work for storing thread IDs for notifications and receipts. ([\matrix-org#13753](matrix-org#13753))
- Re-type hint some collections as read-only. ([\matrix-org#13754](matrix-org#13754))
- Remove unused Prometheus recording rules from `synapse-v2.rules` and add comments describing where the rest are used. ([\matrix-org#13756](matrix-org#13756))
- Add a check for editable installs if the Rust library needs rebuilding. ([\matrix-org#13759](matrix-org#13759))
- Tag traces with the instance name to be able to easily jump into the right logs and filter traces by instance. ([\matrix-org#13761](matrix-org#13761))
- Concurrently fetch room push actions when calculating badge counts. Contributed by Nick @ Beeper (@Fizzadar). ([\matrix-org#13765](matrix-org#13765))
- Update the script which makes full schema dumps. ([\matrix-org#13770](matrix-org#13770))
- Deduplicate `is_server_notices_room`. ([\matrix-org#13780](matrix-org#13780))
- Simplify the dependency DAG in the tests workflow. ([\matrix-org#13784](matrix-org#13784))
- Remove an old, incorrect migration file. ([\matrix-org#13788](matrix-org#13788))
- Remove unused method in `synapse.api.auth.Auth`. ([\matrix-org#13795](matrix-org#13795))
- Fix a memory leak when running the unit tests. ([\matrix-org#13798](matrix-org#13798))
- Use partial indices on SQLite. ([\matrix-org#13802](matrix-org#13802))
- Check that portdb generates the same postgres schema as that in the source tree. ([\matrix-org#13808](matrix-org#13808))
- Fix Docker build when Rust .so has been built locally first. ([\matrix-org#13811](matrix-org#13811))
- Complement: Initialise the Postgres database directly inside the target image instead of the base Postgres image to fix building using Buildah. ([\matrix-org#13819](matrix-org#13819))
- Support providing an index predicate clause when doing upserts. ([\matrix-org#13822](matrix-org#13822))
- Minor speedups to linting in CI. ([\matrix-org#13827](matrix-org#13827))

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# Conflicts:
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#	poetry.lock
#	synapse/push/bulk_push_rule_evaluator.py
#	synapse/push/push_tools.py
#	synapse/storage/databases/main/event_push_actions.py
#	synapse/storage/databases/main/events_worker.py
#	tests/replication/slave/storage/test_events.py
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