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Fetch missing auth events, implement QueryMissingAuthPrevEvents, try other servers in room for /event and /get_missing_events (#1450)

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* Try to ask other servers in the room for missing events if the origin won't provide them

* Logging

* More logging

* Implement QueryMissingAuthPrevEvents

* Try to get missing auth events badly

* Use processEvent

* Logging

* Update QueryMissingAuthPrevEvents

* Try to find missing auth events

* Patchy fix for test

* Logging tweaks

* Send auth events as outliers

* Update check in QueryMissingAuthPrevEvents

* Error responses

* More return codes

* Don't return error on reject/soft-fail since it was ultimately handled

* More tweaks

* More error tweaks
This commit is contained in:
Neil Alexander 2020-09-29 13:40:29 +01:00 • committed by GitHub
parent 4ff7ac7b65
commit 738b829a23
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GPG key ID: 4AEE18F83AFDEB23
12 changed files with 291 additions and 81 deletions
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130
federationapi/routing/send.go
View file

@ -206,10 +206,10 @@ func (t *txnReq) processTransaction(ctx context.Context) (*gomatrixserverlib.Res
return nil, &jsonErr
} else {
// Auth errors mean the event is 'rejected' which have to be silent to appease sytest
errMsg := ""
_, rejected := err.(*gomatrixserverlib.NotAllowed)
errMsg := err.Error()
if rejected {
errMsg = ""
if !rejected {
errMsg = err.Error()
}
util.GetLogger(ctx).WithError(err).WithField("event_id", e.EventID()).WithField("rejected", rejected).Warn(
"Failed to process incoming federation event, skipping",
@ -345,17 +345,17 @@ func (t *txnReq) processDeviceListUpdate(ctx context.Context, e gomatrixserverli
}
func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, isInboundTxn bool) error {
prevEventIDs := e.PrevEventIDs()
logger := util.GetLogger(ctx).WithField("event_id", e.EventID()).WithField("room_id", e.RoomID())
// Fetch the state needed to authenticate the event.
needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{e})
stateReq := api.QueryStateAfterEventsRequest{
// Work out if the roomserver knows everything it needs to know to auth
// the event.
stateReq := api.QueryMissingAuthPrevEventsRequest{
RoomID: e.RoomID(),
PrevEventIDs: prevEventIDs,
StateToFetch: needed.Tuples(),
AuthEventIDs: e.AuthEventIDs(),
PrevEventIDs: e.PrevEventIDs(),
}
var stateResp api.QueryStateAfterEventsResponse
if err := t.rsAPI.QueryStateAfterEvents(ctx, &stateReq, &stateResp); err != nil {
var stateResp api.QueryMissingAuthPrevEventsResponse
if err := t.rsAPI.QueryMissingAuthPrevEvents(ctx, &stateReq, &stateResp); err != nil {
return err
}
@ -369,7 +369,53 @@ func (t *txnReq) processEvent(ctx context.Context, e gomatrixserverlib.Event, is
return roomNotFoundError{e.RoomID()}
}
if !stateResp.PrevEventsExist {
if len(stateResp.MissingAuthEventIDs) > 0 {
logger.Infof("Event refers to %d unknown auth_events", len(stateResp.MissingAuthEventIDs))
servers := []gomatrixserverlib.ServerName{t.Origin}
serverReq := &api.QueryServerJoinedToRoomRequest{
RoomID: e.RoomID(),
}
serverRes := &api.QueryServerJoinedToRoomResponse{}
if err := t.rsAPI.QueryServerJoinedToRoom(ctx, serverReq, serverRes); err == nil {
servers = append(servers, serverRes.ServerNames...)
logger.Infof("Found %d server(s) to query for missing events", len(servers))
}
getAuthEvent:
for _, missingAuthEventID := range stateResp.MissingAuthEventIDs {
for _, server := range servers {
logger.Infof("Retrieving missing auth event %q from %q", missingAuthEventID, server)
tx, err := t.federation.GetEvent(ctx, server, missingAuthEventID)
if err != nil {
continue // try the next server
}
ev, err := gomatrixserverlib.NewEventFromUntrustedJSON(tx.PDUs[0], stateResp.RoomVersion)
if err != nil {
logger.WithError(err).Errorf("Failed to unmarshal auth event %q", missingAuthEventID)
continue // try the next server
}
if err = api.SendInputRoomEvents(
context.Background(),
t.rsAPI,
[]api.InputRoomEvent{
{
Kind: api.KindOutlier,
Event: ev.Headered(stateResp.RoomVersion),
AuthEventIDs: ev.AuthEventIDs(),
SendAsServer: api.DoNotSendToOtherServers,
},
},
); err != nil {
logger.WithError(err).Errorf("Failed to send auth event %q to roomserver", missingAuthEventID)
continue getAuthEvent // move onto the next event
}
}
}
}
if len(stateResp.MissingPrevEventIDs) > 0 {
logger.Infof("Event refers to %d unknown prev_events", len(stateResp.MissingPrevEventIDs))
return t.processEventWithMissingState(ctx, e, stateResp.RoomVersion, isInboundTxn)
}
@ -611,6 +657,7 @@ retryAllowedState:
// begin from. Returns an error only if we should terminate the transaction which initiated /get_missing_events
// This function recursively calls txnReq.processEvent with the missing events, which will be processed before this function returns.
// This means that we may recursively call this function, as we spider back up prev_events to the min depth.
// nolint:gocyclo
func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion, isInboundTxn bool) (backwardsExtremity *gomatrixserverlib.Event, err error) {
if !isInboundTxn {
// we've recursed here, so just take a state snapshot please!
@ -637,15 +684,46 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event
if minDepth < 0 {
minDepth = 0
}
missingResp, err := t.federation.LookupMissingEvents(ctx, t.Origin, e.RoomID(), gomatrixserverlib.MissingEvents{
Limit: 20,
// synapse uses the min depth they've ever seen in that room
MinDepth: minDepth,
// The latest event IDs that the sender already has. These are skipped when retrieving the previous events of latest_events.
EarliestEvents: latestEvents,
// The event IDs to retrieve the previous events for.
LatestEvents: []string{e.EventID()},
}, roomVersion)
servers := []gomatrixserverlib.ServerName{t.Origin}
serverReq := &api.QueryServerJoinedToRoomRequest{
RoomID: e.RoomID(),
}
serverRes := &api.QueryServerJoinedToRoomResponse{}
if err = t.rsAPI.QueryServerJoinedToRoom(ctx, serverReq, serverRes); err == nil {
servers = append(servers, serverRes.ServerNames...)
logger.Infof("Found %d server(s) to query for missing events", len(servers))
}
var missingResp *gomatrixserverlib.RespMissingEvents
for _, server := range servers {
var m gomatrixserverlib.RespMissingEvents
if m, err = t.federation.LookupMissingEvents(ctx, server, e.RoomID(), gomatrixserverlib.MissingEvents{
Limit: 20,
// synapse uses the min depth they've ever seen in that room
MinDepth: minDepth,
// The latest event IDs that the sender already has. These are skipped when retrieving the previous events of latest_events.
EarliestEvents: latestEvents,
// The event IDs to retrieve the previous events for.
LatestEvents: []string{e.EventID()},
}, roomVersion); err == nil {
missingResp = &m
break
} else {
logger.WithError(err).Errorf("%s pushed us an event but %q did not respond to /get_missing_events", t.Origin, server)
}
}
if missingResp == nil {
logger.WithError(err).Errorf(
"%s pushed us an event but %d server(s) couldn't give us details about prev_events via /get_missing_events - dropping this event until it can",
t.Origin, len(servers),
)
return nil, missingPrevEventsError{
eventID: e.EventID(),
err: err,
}
}
// security: how we handle failures depends on whether or not this event will become the new forward extremity for the room.
// There's 2 scenarios to consider:
@ -658,16 +736,6 @@ func (t *txnReq) getMissingEvents(ctx context.Context, e gomatrixserverlib.Event
// https://github.com/matrix-org/synapse/pull/3456
// https://github.com/matrix-org/synapse/blob/229eb81498b0fe1da81e9b5b333a0285acde9446/synapse/handlers/federation.py#L335
// For now, we do not allow Case B, so reject the event.
if err != nil {
logger.WithError(err).Errorf(
"%s pushed us an event but couldn't give us details about prev_events via /get_missing_events - dropping this event until it can",
t.Origin,
)
return nil, missingPrevEventsError{
eventID: e.EventID(),
err: err,
}
}
logger.Infof("get_missing_events returned %d events", len(missingResp.Events))
// topologically sort and sanity check that we are making forward progress

98
federationapi/routing/send_test.go
View file

@ -77,10 +77,11 @@ func (p *testEDUProducer) InputSendToDeviceEvent(
}
type testRoomserverAPI struct {
inputRoomEvents []api.InputRoomEvent
queryStateAfterEvents func(*api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse
queryEventsByID func(req *api.QueryEventsByIDRequest) api.QueryEventsByIDResponse
queryLatestEventsAndState func(*api.QueryLatestEventsAndStateRequest) api.QueryLatestEventsAndStateResponse
inputRoomEvents []api.InputRoomEvent
queryMissingAuthPrevEvents func(*api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse
queryStateAfterEvents func(*api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse
queryEventsByID func(req *api.QueryEventsByIDRequest) api.QueryEventsByIDResponse
queryLatestEventsAndState func(*api.QueryLatestEventsAndStateRequest) api.QueryLatestEventsAndStateResponse
}
func (t *testRoomserverAPI) SetFederationSenderAPI(fsAPI fsAPI.FederationSenderInternalAPI) {}
@ -162,6 +163,20 @@ func (t *testRoomserverAPI) QueryStateAfterEvents(
return nil
}
// Query the state after a list of events in a room from the room server.
func (t *testRoomserverAPI) QueryMissingAuthPrevEvents(
ctx context.Context,
request *api.QueryMissingAuthPrevEventsRequest,
response *api.QueryMissingAuthPrevEventsResponse,
) error {
response.RoomVersion = testRoomVersion
res := t.queryMissingAuthPrevEvents(request)
response.RoomExists = res.RoomExists
response.MissingAuthEventIDs = res.MissingAuthEventIDs
response.MissingPrevEventIDs = res.MissingPrevEventIDs
return nil
}
// Query a list of events by event ID.
func (t *testRoomserverAPI) QueryEventsByID(
ctx context.Context,
@ -453,11 +468,11 @@ func assertInputRoomEvents(t *testing.T, got []api.InputRoomEvent, want []gomatr
// to the roomserver. It's the most basic test possible.
func TestBasicTransaction(t *testing.T) {
rsAPI := &testRoomserverAPI{
queryStateAfterEvents: func(req *api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse {
return api.QueryStateAfterEventsResponse{
PrevEventsExist: true,
RoomExists: true,
StateEvents: fromStateTuples(req.StateToFetch, nil),
queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
return api.QueryMissingAuthPrevEventsResponse{
RoomExists: true,
MissingAuthEventIDs: []string{},
MissingPrevEventIDs: []string{},
}
},
}
@ -473,14 +488,11 @@ func TestBasicTransaction(t *testing.T) {
// as it does the auth check.
func TestTransactionFailAuthChecks(t *testing.T) {
rsAPI := &testRoomserverAPI{
queryStateAfterEvents: func(req *api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse {
return api.QueryStateAfterEventsResponse{
PrevEventsExist: true,
RoomExists: true,
// omit the create event so auth checks fail
StateEvents: fromStateTuples(req.StateToFetch, []gomatrixserverlib.StateKeyTuple{
{EventType: gomatrixserverlib.MRoomCreate, StateKey: ""},
}),
queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
return api.QueryMissingAuthPrevEventsResponse{
RoomExists: true,
MissingAuthEventIDs: []string{"create_event"},
MissingPrevEventIDs: []string{},
}
},
}
@ -504,28 +516,24 @@ func TestTransactionFetchMissingPrevEvents(t *testing.T) {
var rsAPI *testRoomserverAPI // ref here so we can refer to inputRoomEvents inside these functions
rsAPI = &testRoomserverAPI{
queryStateAfterEvents: func(req *api.QueryStateAfterEventsRequest) api.QueryStateAfterEventsResponse {
// we expect this to be called three times:
// - first with input event to realise there's a gap
// - second with the prevEvent to realise there is no gap
// - third with the input event to realise there is no longer a gap
prevEventsExist := false
queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
missingPrevEvent := []string{"missing_prev_event"}
if len(req.PrevEventIDs) == 1 {
switch req.PrevEventIDs[0] {
case haveEvent.EventID():
prevEventsExist = true
missingPrevEvent = []string{}
case prevEvent.EventID():
// we only have this event if we've been send prevEvent
if len(rsAPI.inputRoomEvents) == 1 && rsAPI.inputRoomEvents[0].Event.EventID() == prevEvent.EventID() {
prevEventsExist = true
missingPrevEvent = []string{}
}
}
}
return api.QueryStateAfterEventsResponse{
PrevEventsExist: prevEventsExist,
RoomExists: true,
StateEvents: fromStateTuples(req.StateToFetch, nil),
return api.QueryMissingAuthPrevEventsResponse{
RoomExists: true,
MissingAuthEventIDs: []string{},
MissingPrevEventIDs: missingPrevEvent,
}
},
queryLatestEventsAndState: func(req *api.QueryLatestEventsAndStateRequest) api.QueryLatestEventsAndStateResponse {
@ -626,6 +634,38 @@ func TestTransactionFetchMissingStateByStateIDs(t *testing.T) {
StateEvents: stateEvents,
}
},
queryMissingAuthPrevEvents: func(req *api.QueryMissingAuthPrevEventsRequest) api.QueryMissingAuthPrevEventsResponse {
askingForEvent := req.PrevEventIDs[0]
haveEventB := false
haveEventC := false
for _, ev := range rsAPI.inputRoomEvents {
switch ev.Event.EventID() {
case eventB.EventID():
haveEventB = true
case eventC.EventID():
haveEventC = true
}
}
prevEventExists := false
if askingForEvent == eventC.EventID() {
prevEventExists = haveEventC
} else if askingForEvent == eventB.EventID() {
prevEventExists = haveEventB
}
var missingPrevEvent []string
if !prevEventExists {
missingPrevEvent = []string{"test"}
}
return api.QueryMissingAuthPrevEventsResponse{
RoomExists: true,
MissingAuthEventIDs: []string{},
MissingPrevEventIDs: missingPrevEvent,
}
},
queryLatestEventsAndState: func(req *api.QueryLatestEventsAndStateRequest) api.QueryLatestEventsAndStateResponse {
omitTuples := []gomatrixserverlib.StateKeyTuple{
{EventType: gomatrixserverlib.MRoomPowerLevels, StateKey: ""},