There is a corner in `_check_event_auth` (long known as "the weird corner") where, if we get an event with auth_events which don't match those we were expecting, we attempt to resolve the diffence between our state and the remote's with a state resolution.
This isn't specced, and there's general agreement we shouldn't be doing it.
However, it turns out that the faster-joins code was relying on it, so we need to introduce something similar (but rather simpler) for that.
It seems like calling `_get_state_group_for_events` for an event where the
state is unknown is an error. Accordingly, let's raise an exception rather than
silently returning an empty result.
* `_auth_and_persist_outliers`: mark persisted events as outliers
Mark any events that get persisted via `_auth_and_persist_outliers` as, well,
outliers.
Currently this will be a no-op as everything will already be flagged as an
outlier, but I'm going to change that.
* `process_remote_join`: stop flagging as outlier
The events are now flagged as outliers later on, by `_auth_and_persist_outliers`.
* `send_join`: remove `outlier=True`
The events created here are returned in the result of `send_join` to
`FederationHandler.do_invite_join`. From there they are passed into
`FederationEventHandler.process_remote_join`, which passes them to
`_auth_and_persist_outliers`... which sets the `outlier` flag.
* `get_event_auth`: remove `outlier=True`
stop flagging the events returned by `get_event_auth` as outliers. This method
is only called by `_get_remote_auth_chain_for_event`, which passes the results
into `_auth_and_persist_outliers`, which will flag them as outliers.
* `_get_remote_auth_chain_for_event`: remove `outlier=True`
we pass all the events into `_auth_and_persist_outliers`, which will now flag
the events as outliers.
* `_check_sigs_and_hash_and_fetch`: remove unused `outlier` parameter
This param is now never set to True, so we can remove it.
* `_check_sigs_and_hash_and_fetch_one`: remove unused `outlier` param
This is no longer set anywhere, so we can remove it.
* `get_pdu`: remove unused `outlier` parameter
... and chase it down into `get_pdu_from_destination_raw`.
* `event_from_pdu_json`: remove redundant `outlier` param
This is never set to `True`, so can be removed.
* changelog
* update docstring
Found while working on the Gitter backfill script and noticed
it only happened after we sent 7 batches, https://gitlab.com/gitterHQ/webapp/-/merge_requests/2229#note_665906390
When there are more than 5 backward extremities for a given depth,
backfill will throw an error because we sliced the extremity list
to 5 but then try to iterate over the full list. This causes
us to look for state that we never fetched and we get a `KeyError`.
Before when calling `/messages` when there are more than 5 backward extremities:
```
Traceback (most recent call last):
File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 258, in _async_render_wrapper
callback_return = await self._async_render(request)
File "/usr/local/lib/python3.8/site-packages/synapse/http/server.py", line 446, in _async_render
callback_return = await raw_callback_return
File "/usr/local/lib/python3.8/site-packages/synapse/rest/client/room.py", line 580, in on_GET
msgs = await self.pagination_handler.get_messages(
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/pagination.py", line 396, in get_messages
await self.hs.get_federation_handler().maybe_backfill(
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 133, in maybe_backfill
return await self._maybe_backfill_inner(room_id, current_depth, limit)
File "/usr/local/lib/python3.8/site-packages/synapse/handlers/federation.py", line 386, in _maybe_backfill_inner
likely_extremeties_domains = get_domains_from_state(states[e_id])
KeyError: '$zpFflMEBtZdgcMQWTakaVItTLMjLFdKcRWUPHbbSZJl'
```
* Factor more stuff out of `_get_events_and_persist`
It turns out that the event-sorting algorithm in `_get_events_and_persist` is
also useful in other circumstances. Here we move the current
`_auth_and_persist_fetched_events` to `_auth_and_persist_fetched_events_inner`,
and then factor the sorting part out to `_auth_and_persist_fetched_events`.
* `_get_remote_auth_chain_for_event`: remove redundant `outlier` assignment
`get_event_auth` returns events with the outlier flag already set, so this is
redundant (though we need to update a test where `get_event_auth` is mocked).
* `_get_remote_auth_chain_for_event`: move existing-event tests earlier
Move a couple of tests outside the loop. This is a bit inefficient for now, but
a future commit will make it better. It should be functionally identical.
* `_get_remote_auth_chain_for_event`: use `_auth_and_persist_fetched_events`
We can use the same codepath for persisting the events fetched as part of an
auth chain as for those fetched individually by `_get_events_and_persist` for
building the state at a backwards extremity.
* `_get_remote_auth_chain_for_event`: use a dict for efficiency
`_auth_and_persist_fetched_events` sorts the events itself, so we no longer
need to care about maintaining the ordering from `get_event_auth` (and no
longer need to sort by depth in `get_event_auth`).
That means that we can use a map, making it easier to filter out events we
already have, etc.
* changelog
* `_auth_and_persist_fetched_events`: improve docstring
Reproducible on a federated homeserver when there is a membership auth event as a floating outlier. Then when we try to backfill one of that persons messages, it has missing membership auth to fetch which caused us to mistakenly replace the `context` for the message with that of the floating membership `outlier` event. Since `outliers` have no `state` or `state_group`, the error bubbles up when we continue down the persisting route: `sqlite3.IntegrityError: NOT NULL constraint failed: event_to_state_groups.state_group`
Call stack:
```
backfill
_auth_and_persist_event
_check_event_auth
_update_auth_events_and_context_for_auth
```
The idea here is to stop people sending things that aren't joins/leaves/knocks through these endpoints: previously you could send anything you liked through them. I wasn't able to find any security holes from doing so, but it doesn't sound like a good thing.
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
- Update black version to the latest
- Run black auto formatting over the codebase
- Run autoformatting according to [`docs/code_style.md
`](80d6dc9783/docs/code_style.md)
- Update `code_style.md` docs around installing black to use the correct version
Replaces the `federation_ip_range_blacklist` configuration setting with an
`ip_range_blacklist` setting with wider scope. It now applies to:
* Federation
* Identity servers
* Push notifications
* Checking key validitity for third-party invite events
The old `federation_ip_range_blacklist` setting is still honored if present, but
with reduced scope (it only applies to federation and identity servers).
* Consistently use room_id from federation request body
Some federation APIs have a redundant `room_id` path param (see
https://github.com/matrix-org/matrix-doc/issues/2330). We should make sure we
consistently use either the path param or the body param, and the body param is
easier.
* Kill off some references to "context"
Once upon a time, "rooms" were known as "contexts". I think this kills of the
last references to "contexts".
Fixes a bug where rejected events were persisted with the wrong state group.
Also fixes an occasional internal-server-error when receiving events over
federation which are rejected and (possibly because they are
backwards-extremities) have no prev_group.
Fixes#6289.
