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Fixing the incoming events algorithm (review with time)

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This commit is contained in:
Devin Ragotzy 2021-01-16 16:37:20 -05:00
parent 96dc6be14b
commit b1ae2bbeb2
2 changed files with 138 additions and 101 deletions
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2
src/database/rooms.rs
View file

@ -150,7 +150,7 @@ impl Rooms {
}
}
/// Returns the last state hash key added to the db.
/// Returns the state hash for this pdu.
pub fn pdu_state_hash(&self, pdu_id: &[u8]) -> Result<Option<StateHashId>> {
Ok(self.pduid_statehash.get(pdu_id)?)
}

237
src/server_server.rs
View file

@ -5,6 +5,7 @@ use log::{error, info, warn};
use rocket::{get, post, put, response::content::Json, State};
use ruma::{
api::{
client::r0::state,
federation::{
directory::{get_public_rooms, get_public_rooms_filtered},
discovery::{
@ -590,6 +591,8 @@ pub async fn send_transaction_message_route<'a>(
continue;
}
};
// 1. check the server is in the room (optional)
if !db.rooms.exists(&room_id)? {
resolved_map.insert(event_id, Err("Room is unknown to this server".to_string()));
continue;
@ -634,14 +637,13 @@ pub async fn send_transaction_message_route<'a>(
// the auth events that it references.
let mut auth_cache = EventMap::new();
// 1. check the server is in the room (optional)
// 2. check content hash, redact if doesn't match
// 3. fetch any missing auth events doing all checks listed here starting at 1. These are not timeline events
// 4. reject "due to auth events" if can't get all the auth events or some of the auth events are also rejected "due to auth events"
// 5. reject "due to auth events" if the event doesn't pass auth based on the auth events
// 6. persist this event as an outlier
// 7. if not timeline event: stop
let pdu = match validate_event(
// 8. fetch any missing prev events doing all checks listed here starting at 1. These are timeline events
let (pdu, previous) = match validate_event(
&db,
value,
event_id.clone(),
@ -659,59 +661,16 @@ pub async fn send_transaction_message_route<'a>(
}
};
let pdu = Arc::new(pdu.clone());
// Fetch any unknown prev_events or retrieve them from the DB
let previous = match fetch_events(
&db,
server_name,
&pub_key_map,
&pdu.prev_events,
&mut auth_cache,
)
.await
{
Ok(mut evs) if evs.len() == 1 => Some(evs.remove(0)),
_ => None,
let single_prev = if previous.len() == 1 {
previous.first().cloned()
} else {
None
};
// [auth_cache] At this point we have the auth chain of the incoming event.
let mut event_map: state_res::EventMap<Arc<PduEvent>> = auth_cache
.iter()
.map(|(k, v)| (k.clone(), v.clone()))
.collect();
// 6. persist the event as an outlier.
db.rooms.append_pdu_outlier(pdu.event_id(), &pdu)?;
// Check that the event passes auth based on the auth_events
let is_authed = state_res::event_auth::auth_check(
&RoomVersionId::Version6,
&pdu,
previous.clone(),
&pdu.auth_events
.iter()
.map(|id| {
auth_cache
.get(id)
.map(|pdu| ((pdu.kind(), pdu.state_key()), pdu.clone()))
.ok_or_else(|| {
Error::Conflict(
"Auth event not found, event failed recursive auth checks.",
)
})
})
.collect::<Result<BTreeMap<_, _>>>()?,
None, // TODO: third party invite
)
.map_err(|_e| Error::Conflict("Auth check failed"))?;
if !is_authed {
resolved_map.insert(
pdu.event_id().clone(),
Err("Event has failed auth check with auth events".into()),
);
continue;
}
// End of step 4.
// Step 5. event passes auth based on state at the event
// Step 10. check the auth of the event passes based on the calculated state of the event
let (state_at_event, incoming_auth_events): (StateMap<Arc<PduEvent>>, Vec<Arc<PduEvent>>) =
match db
.sending
@ -757,9 +716,7 @@ pub async fn send_transaction_message_route<'a>(
&res.auth_chain_ids,
&mut auth_cache,
)
.await?
.into_iter()
.collect(),
.await?,
)
}
Err(_) => {
@ -771,10 +728,11 @@ pub async fn send_transaction_message_route<'a>(
}
};
// 10. This is the actual auth check for state at the event
if !state_res::event_auth::auth_check(
&RoomVersionId::Version6,
&pdu,
previous.clone(),
single_prev.clone(),
&state_at_event,
None, // TODO: third party invite
)
@ -787,10 +745,34 @@ pub async fn send_transaction_message_route<'a>(
);
continue;
}
// End of step 5.
// End of step 10.
// 12. check if the event passes auth based on the "current state" of the room, if not "soft fail" it
let current_state = db
.rooms
.room_state_full(pdu.room_id())?
.into_iter()
.map(|(k, v)| ((k.0, Some(k.1)), Arc::new(v)))
.collect();
if !state_res::event_auth::auth_check(
&RoomVersionId::Version6,
&pdu,
single_prev.clone(),
&current_state,
None,
)
.map_err(|_e| Error::Conflict("Auth check failed"))?
{
// Soft fail, we add the event as an outlier.
resolved_map.insert(
pdu.event_id().clone(),
Err("Event has been soft failed".into()),
);
};
// Gather the forward extremities and resolve
let fork_states = match forward_extremity_ids(
let fork_states = match forward_extremities(
&db,
&pdu,
server_name,
@ -806,7 +788,9 @@ pub async fn send_transaction_message_route<'a>(
}
};
// Step 6. event passes auth based on state of all forks and current room state
// 13. start state-res with all previous forward extremities minus the ones that are in
// the prev_events of this event plus the new one created by this event and use
// the result as the new room state
let state_at_forks = if fork_states.is_empty() {
// State is empty
Default::default()
@ -852,6 +836,7 @@ pub async fn send_transaction_message_route<'a>(
}
info!("{} event's were not in the auth_cache", number_fetches);
let mut event_map = EventMap::new();
// Add everything we will need to event_map
event_map.extend(
auth_events
@ -904,7 +889,7 @@ pub async fn send_transaction_message_route<'a>(
if !state_res::event_auth::auth_check(
&RoomVersionId::Version6,
&pdu,
previous,
single_prev,
&state_at_forks,
None,
)
@ -925,14 +910,19 @@ pub async fn send_transaction_message_route<'a>(
Ok(dbg!(send_transaction_message::v1::Response { pdus: resolved_map }).into())
}
/// An async function that can recursively calls itself.
type AsyncRecursiveResult<'a, T> = Pin<Box<dyn Future<Output = StdResult<T, String>> + 'a + Send>>;
/// TODO: don't add as outlier if event is fetched as a result of gathering auth_events
/// Validate any event that is given to us by another server.
///
/// 1. Is a valid event, otherwise it is dropped (PduEvent deserialization satisfies this).
/// 2. Passes signature checks, otherwise event is dropped.
/// 3. Passes hash checks, otherwise it is redacted before being processed further.
/// 4. Passes auth_chain collection (we can gather the events that auth this event recursively).
/// 5. Once the event has passed all checks it can be added as an outlier to the DB.
/// 2. check content hash, redact if doesn't match
/// 3. fetch any missing auth events doing all checks listed here starting at 1. These are not timeline events
/// 4. reject "due to auth events" if can't get all the auth events or some of the auth events are also rejected "due to auth events"
/// 5. reject "due to auth events" if the event doesn't pass auth based on the auth events
/// 7. if not timeline event: stop
/// 8. fetch any missing prev events doing all checks listed here starting at 1. These are timeline events
fn validate_event<'a>(
db: &'a Database,
value: CanonicalJsonObject,
@ -940,9 +930,24 @@ fn validate_event<'a>(
pub_key_map: &'a PublicKeyMap,
origin: &'a ServerName,
auth_cache: &'a mut EventMap<Arc<PduEvent>>,
) -> Pin<Box<dyn Future<Output = StdResult<PduEvent, String>> + 'a + Send>> {
) -> AsyncRecursiveResult<'a, (Arc<PduEvent>, Vec<Arc<PduEvent>>)> {
Box::pin(async move {
let mut val = signature_and_hash_check(&pub_key_map, value)?;
let mut val =
match ruma::signatures::verify_event(pub_key_map, &value, &RoomVersionId::Version6) {
Ok(ver) => {
if let ruma::signatures::Verified::Signatures = ver {
match ruma::signatures::redact(&value, &RoomVersionId::Version6) {
Ok(obj) => obj,
Err(_) => return Err("Redaction failed".to_string()),
}
} else {
value
}
}
Err(_e) => {
return Err("Signature verification failed".to_string());
}
};
// Now that we have checked the signature and hashes we can add the eventID and convert
// to our PduEvent type also finally verifying the first step listed above
@ -959,11 +964,42 @@ fn validate_event<'a>(
.await
.map_err(|_| "Event failed auth chain check".to_string())?;
db.rooms
.append_pdu_outlier(pdu.event_id(), &pdu)
let pdu = Arc::new(pdu.clone());
// 8. fetch any missing prev events doing all checks listed here starting at 1. These are timeline events
let previous = fetch_events(&db, origin, &pub_key_map, &pdu.prev_events, auth_cache)
.await
.map_err(|e| e.to_string())?;
Ok(pdu)
// Check that the event passes auth based on the auth_events
let is_authed = state_res::event_auth::auth_check(
&RoomVersionId::Version6,
&pdu,
if previous.len() == 1 {
previous.first().cloned()
} else {
None
},
&pdu.auth_events
.iter()
.map(|id| {
auth_cache
.get(id)
.map(|pdu| ((pdu.kind(), pdu.state_key()), pdu.clone()))
.ok_or_else(|| {
"Auth event not found, event failed recursive auth checks.".to_string()
})
})
.collect::<StdResult<BTreeMap<_, _>, _>>()?,
None, // TODO: third party invite
)
.map_err(|_e| "Auth check failed".to_string())?;
if !is_authed {
return Err("Event has failed auth check with auth events".to_string());
}
Ok((pdu, previous))
})
}
@ -990,7 +1026,10 @@ async fn fetch_check_auth_events(
let ev = fetch_events(db, origin, key_map, &[ev_id.clone()], auth_cache)
.await
.map(|mut vec| vec.remove(0))?;
.map(|mut vec| {
vec.pop()
.ok_or_else(|| Error::Conflict("Event was not found in fetch_events"))
})??;
stack.extend(ev.auth_events());
auth_cache.insert(ev.event_id().clone(), ev);
@ -1028,11 +1067,12 @@ async fn fetch_events(
{
Ok(res) => {
let (event_id, value) = crate::pdu::gen_event_id_canonical_json(&res.pdu);
let pdu = validate_event(db, value, event_id, key_map, origin, auth_cache)
.await
.map_err(|_| Error::Conflict("Authentication of event failed"))?;
let (pdu, _) =
validate_event(db, value, event_id, key_map, origin, auth_cache)
.await
.map_err(|_| Error::Conflict("Authentication of event failed"))?;
Arc::new(pdu)
pdu
}
Err(_) => return Err(Error::BadServerResponse("Failed to fetch event")),
},
@ -1063,31 +1103,11 @@ async fn fetch_signing_keys(
}
}
fn signature_and_hash_check(
pub_key_map: &ruma::signatures::PublicKeyMap,
value: CanonicalJsonObject,
) -> std::result::Result<CanonicalJsonObject, String> {
Ok(
match ruma::signatures::verify_event(pub_key_map, &value, &RoomVersionId::Version6) {
Ok(ver) => {
if let ruma::signatures::Verified::Signatures = ver {
error!("CONTENT HASH FAILED");
match ruma::signatures::redact(&value, &RoomVersionId::Version6) {
Ok(obj) => obj,
Err(_) => return Err("Redaction failed".to_string()),
}
} else {
value
}
}
Err(_e) => {
return Err("Signature verification failed".to_string());
}
},
)
}
async fn forward_extremity_ids(
/// Gather all state snapshots needed to resolve the current state of the room.
///
/// Step 11. ensure that the state is derived from the previous current state (i.e. we calculated by doing state res
/// where one of the inputs was a previously trusted set of state, don't just trust a set of state we got from a remote)
async fn forward_extremities(
db: &Database,
pdu: &PduEvent,
origin: &ServerName,
@ -1102,6 +1122,8 @@ async fn forward_extremity_ids(
}
}
let current_hash = db.rooms.current_state_hash(pdu.room_id())?;
let mut includes_current_state = false;
let mut fork_states = vec![];
for id in &current_leaves {
if let Some(id) = db.rooms.get_pdu_id(id)? {
@ -1109,6 +1131,10 @@ async fn forward_extremity_ids(
.rooms
.pdu_state_hash(&id)?
.expect("found pdu with no statehash");
if current_hash.as_ref() == Some(&state_hash) {
includes_current_state = true;
}
let state = db
.rooms
.state_full(&pdu.room_id, &state_hash)?
@ -1144,6 +1170,17 @@ async fn forward_extremity_ids(
}
}
// This guarantees that our current room state is included
if !includes_current_state && current_hash.is_some() {
fork_states.push(
db.rooms
.state_full(pdu.room_id(), current_hash.as_ref().unwrap())?
.into_iter()
.map(|(k, v)| ((k.0, Some(k.1)), Arc::new(v)))
.collect(),
)
}
Ok(fork_states)
}