tuwunel_service/rooms/event_handler/
handle_outlier_pdu.rs

1use futures::{StreamExt, TryFutureExt};
2use ruma::{
3	CanonicalJsonObject, EventId, RoomId, RoomVersionId, ServerName, events::TimelineEventType,
4};
5use tuwunel_core::{
6	Err, Result, debug, debug_info, err, implement,
7	matrix::{Event, PduEvent, event::TypeExt, room_version},
8	ref_at, trace,
9	utils::{future::TryExtExt, stream::IterStream},
10	warn,
11};
12
13use crate::rooms::state_res;
14
15#[implement(super::Service)]
16#[cfg_attr(unabridged, tracing::instrument(
17    name = "outlier",
18    level = "debug",
19    skip_all,
20    fields(lev = %recursion_level)
21))]
22#[expect(clippy::too_many_arguments)]
23pub(super) async fn handle_outlier_pdu(
24	&self,
25	origin: &ServerName,
26	room_id: &RoomId,
27	event_id: &EventId,
28	mut pdu_json: CanonicalJsonObject,
29	room_version: &RoomVersionId,
30	recursion_level: usize,
31	auth_events_known: bool,
32) -> Result<(PduEvent, CanonicalJsonObject)> {
33	debug!(?event_id, ?auth_events_known, %recursion_level, "handle outlier");
34
35	// 1. Remove unsigned field
36	pdu_json.remove("unsigned");
37
38	// TODO: For RoomVersion6 we must check that Raw<..> is canonical do we
39	// anywhere?: https://matrix.org/docs/spec/rooms/v6#canonical-json
40	// 2. Check signatures, otherwise drop
41	// 3. check content hash, redact if doesn't match
42	let pdu_json = match self
43		.services
44		.server_keys
45		.verify_event(&pdu_json, Some(room_version))
46		.await
47	{
48		| Ok(ruma::signatures::Verified::All) => pdu_json,
49		| Ok(ruma::signatures::Verified::Signatures) => {
50			// Redact
51			debug_info!("Calculated hash does not match (redaction): {event_id}");
52			let Some(rules) = room_version.rules() else {
53				return Err!(Request(UnsupportedRoomVersion(
54					"Cannot redact event for unknown room version {room_version:?}."
55				)));
56			};
57
58			let Ok(pdu_json) = ruma::canonical_json::redact(pdu_json, &rules.redaction, None)
59			else {
60				return Err!(Request(InvalidParam("Redaction failed")));
61			};
62
63			// Skip the PDU if it is redacted and we already have it as an outlier event
64			if self.services.timeline.pdu_exists(event_id).await {
65				return Err!(Request(InvalidParam(
66					"Event was redacted and we already knew about it"
67				)));
68			}
69
70			pdu_json
71		},
72		| Err(e) => {
73			return Err!(Request(InvalidParam(debug_error!(
74				"Signature verification failed for {event_id}: {e}"
75			))));
76		},
77	};
78
79	// Now that we have checked the signature and hashes we can make mutations and
80	// convert to our PduEvent type.
81	let room_rules = room_version::rules(room_version)?;
82	let (event, pdu_json) =
83		PduEvent::from_object_federation(room_id, event_id, pdu_json, &room_rules)?;
84
85	if !auth_events_known {
86		// 4. fetch any missing auth events doing all checks listed here starting at 1.
87		//    These are not timeline events
88		// 5. Reject "due to auth events" if can't get all the auth events or some of
89		//    the auth events are also rejected "due to auth events"
90		// NOTE: Step 5 is not applied anymore because it failed too often
91		debug!("Fetching auth events");
92		Box::pin(self.fetch_auth(
93			origin,
94			room_id,
95			event.auth_events(),
96			room_version,
97			recursion_level,
98		))
99		.await;
100	}
101
102	// 6. Reject "due to auth events" if the event doesn't pass auth based on the
103	//    auth events
104	debug!("Checking based on auth events");
105
106	let is_hydra = !room_rules
107		.event_format
108		.allow_room_create_in_auth_events;
109
110	let not_create = *event.kind() != TimelineEventType::RoomCreate;
111	let hydra_create_id = (not_create && is_hydra)
112		.then(|| event.room_id().as_event_id().ok())
113		.flatten();
114
115	let auth_events: Vec<_> = event
116		.auth_events()
117		.chain(hydra_create_id.as_deref())
118		.stream()
119		.filter_map(|auth_event_id| {
120			self.event_fetch(auth_event_id)
121				.inspect_err(move |e| warn!("Missing auth_event {auth_event_id}: {e}"))
122				.ok()
123		})
124		.map(|auth_event| {
125			let event_type = auth_event.event_type();
126			let state_key = auth_event
127				.state_key()
128				.expect("all auth events have state_key");
129
130			(event_type.with_state_key(state_key), auth_event)
131		})
132		.collect()
133		.await;
134
135	state_res::auth_check(
136		&room_rules,
137		&event,
138		&async |event_id| self.event_fetch(&event_id).await,
139		&async |event_type, state_key| {
140			let target = event_type.with_state_key(state_key);
141			auth_events
142				.iter()
143				.find(|(type_state_key, _)| *type_state_key == target)
144				.map(ref_at!(1))
145				.cloned()
146				.ok_or_else(|| err!(Request(NotFound("state not found"))))
147		},
148	)
149	.inspect_ok(|()| trace!("Validation successful."))
150	.await?;
151
152	// 7. Persist the event as an outlier.
153	self.services
154		.timeline
155		.add_pdu_outlier(event.event_id(), &pdu_json);
156
157	trace!("Added pdu as outlier.");
158
159	Ok((event, pdu_json))
160}
tuwunel_service/rooms/event_handler/handle_outlier_pdu.rs

tuwunel_service/rooms/event_handler/
handle_outlier_pdu.rs
