dendrite/roomserver/internal/input/input_events.go
2021-12-15 13:59:58 +00:00

660 lines
23 KiB
Go

// Copyright 2017 Vector Creations Ltd
// Copyright 2018 New Vector Ltd
// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package input
import (
"bytes"
"context"
"fmt"
"time"
fedapi "github.com/matrix-org/dendrite/federationapi/api"
"github.com/matrix-org/dendrite/internal"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/roomserver/internal/helpers"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
"github.com/prometheus/client_golang/prometheus"
"github.com/sirupsen/logrus"
)
func init() {
prometheus.MustRegister(processRoomEventDuration)
}
var processRoomEventDuration = prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Namespace: "dendrite",
Subsystem: "roomserver",
Name: "processroomevent_duration_millis",
Help: "How long it takes the roomserver to process an event",
Buckets: []float64{ // milliseconds
5, 10, 25, 50, 75, 100, 250, 500,
1000, 2000, 3000, 4000, 5000, 6000,
7000, 8000, 9000, 10000, 15000, 20000,
},
},
[]string{"room_id"},
)
// processRoomEvent can only be called once at a time
//
// TODO(#375): This should be rewritten to allow concurrent calls. The
// difficulty is in ensuring that we correctly annotate events with the correct
// state deltas when sending to kafka streams
// TODO: Break up function - we should probably do transaction ID checks before calling this.
// nolint:gocyclo
func (r *Inputer) processRoomEvent(
ctx context.Context,
input *api.InputRoomEvent,
) (eventID string, err error) {
// Measure how long it takes to process this event.
started := time.Now()
defer func() {
timetaken := time.Since(started)
processRoomEventDuration.With(prometheus.Labels{
"room_id": input.Event.RoomID(),
}).Observe(float64(timetaken.Milliseconds()))
}()
// Parse and validate the event JSON
headered := input.Event
event := headered.Unwrap()
logger := util.GetLogger(ctx).WithFields(logrus.Fields{
"event_id": event.EventID(),
"room_id": event.RoomID(),
"type": event.Type(),
})
// if we have already got this event then do not process it again, if the input kind is an outlier.
// Outliers contain no extra information which may warrant a re-processing.
if input.Kind == api.KindOutlier {
evs, err2 := r.DB.EventsFromIDs(ctx, []string{event.EventID()})
if err2 == nil && len(evs) == 1 {
// check hash matches if we're on early room versions where the event ID was a random string
idFormat, err2 := headered.RoomVersion.EventIDFormat()
if err2 == nil {
switch idFormat {
case gomatrixserverlib.EventIDFormatV1:
if bytes.Equal(event.EventReference().EventSHA256, evs[0].EventReference().EventSHA256) {
logger.Debugf("Already processed event; ignoring")
return event.EventID(), nil
}
default:
logger.Debugf("Already processed event; ignoring")
return event.EventID(), nil
}
}
}
}
missingReq := &api.QueryMissingAuthPrevEventsRequest{
RoomID: event.RoomID(),
AuthEventIDs: event.AuthEventIDs(),
PrevEventIDs: event.PrevEventIDs(),
}
missingRes := &api.QueryMissingAuthPrevEventsResponse{}
if event.Type() != gomatrixserverlib.MRoomCreate {
if err = r.Queryer.QueryMissingAuthPrevEvents(ctx, missingReq, missingRes); err != nil {
return "", fmt.Errorf("r.Queryer.QueryMissingAuthPrevEvents: %w", err)
}
}
// First of all, check that the auth events of the event are known.
// If they aren't then we will ask the federation API for them.
isRejected := false
authEvents := gomatrixserverlib.NewAuthEvents(nil)
knownEvents := map[string]*types.Event{}
if err = r.checkForMissingAuthEvents(ctx, logger, input.Event, &authEvents, knownEvents); err != nil {
return "", fmt.Errorf("r.checkForMissingAuthEvents: %w", err)
}
// Check if the event is allowed by its auth events. If it isn't then
// we consider the event to be "rejected" — it will still be persisted.
var rejectionErr error
if rejectionErr = gomatrixserverlib.Allowed(event, &authEvents); rejectionErr != nil {
isRejected = true
logger.WithError(rejectionErr).Warnf("Event %s rejected", event.EventID())
}
// Accumulate the auth event NIDs.
authEventIDs := event.AuthEventIDs()
authEventNIDs := make([]types.EventNID, 0, len(authEventIDs))
for _, authEventID := range authEventIDs {
authEventNIDs = append(authEventNIDs, knownEvents[authEventID].EventNID)
}
var softfail bool
if input.Kind == api.KindNew {
// Check that the event passes authentication checks based on the
// current room state.
softfail, err = helpers.CheckForSoftFail(ctx, r.DB, headered, input.StateEventIDs)
if err != nil {
logger.WithError(err).Info("Error authing soft-failed event")
}
}
// Store the event.
_, _, stateAtEvent, redactionEvent, redactedEventID, err := r.DB.StoreEvent(ctx, event, authEventNIDs, isRejected)
if err != nil {
return "", fmt.Errorf("r.DB.StoreEvent: %w", err)
}
// if storing this event results in it being redacted then do so.
if !isRejected && redactedEventID == event.EventID() {
r, rerr := eventutil.RedactEvent(redactionEvent, event)
if rerr != nil {
return "", fmt.Errorf("eventutil.RedactEvent: %w", rerr)
}
event = r
}
// For outliers we can stop after we've stored the event itself as it
// doesn't have any associated state to store and we don't need to
// notify anyone about it.
if input.Kind == api.KindOutlier {
logger.Debug("Stored outlier")
return event.EventID(), nil
}
roomInfo, err := r.DB.RoomInfo(ctx, event.RoomID())
if err != nil {
return "", fmt.Errorf("r.DB.RoomInfo: %w", err)
}
if roomInfo == nil {
return "", fmt.Errorf("r.DB.RoomInfo missing for room %s", event.RoomID())
}
if input.Origin == "" {
return "", fmt.Errorf("expected an origin")
}
if len(missingRes.MissingPrevEventIDs) > 0 {
missingState := missingStateReq{
origin: input.Origin,
inputer: r,
queryer: r.Queryer,
db: r.DB,
federation: r.FSAPI,
roomsMu: internal.NewMutexByRoom(),
servers: []gomatrixserverlib.ServerName{input.Origin},
hadEvents: map[string]bool{},
haveEvents: map[string]*gomatrixserverlib.HeaderedEvent{},
}
if err = missingState.processEventWithMissingState(ctx, input.Event.Unwrap(), roomInfo.RoomVersion); err != nil {
return "", fmt.Errorf("r.checkForMissingPrevEvents: %w", err)
}
}
if stateAtEvent.BeforeStateSnapshotNID == 0 {
// We haven't calculated a state for this event yet.
// Lets calculate one.
err = r.calculateAndSetState(ctx, input, *roomInfo, &stateAtEvent, event, isRejected)
if err != nil && input.Kind != api.KindOld {
return "", fmt.Errorf("r.calculateAndSetState: %w", err)
}
}
// We stop here if the event is rejected: We've stored it but won't update forward extremities or notify anyone about it.
if isRejected || softfail {
logger.WithField("soft_fail", softfail).Debug("Stored rejected event")
return event.EventID(), rejectionErr
}
switch input.Kind {
case api.KindNew:
if err = r.updateLatestEvents(
ctx, // context
roomInfo, // room info for the room being updated
stateAtEvent, // state at event (below)
event, // event
input.SendAsServer, // send as server
input.TransactionID, // transaction ID
input.HasState, // rewrites state?
); err != nil {
return "", fmt.Errorf("r.updateLatestEvents: %w", err)
}
case api.KindOld:
err = r.WriteOutputEvents(event.RoomID(), []api.OutputEvent{
{
Type: api.OutputTypeOldRoomEvent,
OldRoomEvent: &api.OutputOldRoomEvent{
Event: headered,
},
},
})
if err != nil {
return "", fmt.Errorf("r.WriteOutputEvents (old): %w", err)
}
}
// processing this event resulted in an event (which may not be the one we're processing)
// being redacted. We are guaranteed to have both sides (the redaction/redacted event),
// so notify downstream components to redact this event - they should have it if they've
// been tracking our output log.
if redactedEventID != "" {
err = r.WriteOutputEvents(event.RoomID(), []api.OutputEvent{
{
Type: api.OutputTypeRedactedEvent,
RedactedEvent: &api.OutputRedactedEvent{
RedactedEventID: redactedEventID,
RedactedBecause: redactionEvent.Headered(headered.RoomVersion),
},
},
})
if err != nil {
return "", fmt.Errorf("r.WriteOutputEvents (redactions): %w", err)
}
}
// Update the extremities of the event graph for the room
return event.EventID(), nil
}
func (r *Inputer) checkForMissingAuthEvents(
ctx context.Context,
logger *logrus.Entry,
event *gomatrixserverlib.HeaderedEvent,
auth *gomatrixserverlib.AuthEvents,
known map[string]*types.Event,
) error {
authEventIDs := event.AuthEventIDs()
if len(authEventIDs) == 0 {
return nil
}
unknown := map[string]struct{}{}
authEvents, err := r.DB.EventsFromIDs(ctx, authEventIDs)
if err != nil {
return fmt.Errorf("r.DB.EventsFromIDs: %w", err)
}
for _, event := range authEvents {
if event.Event != nil {
ev := event // don't take the address of the iterated value
known[event.EventID()] = &ev
if err = auth.AddEvent(event.Event); err != nil {
return fmt.Errorf("auth.AddEvent: %w", err)
}
} else {
unknown[event.EventID()] = struct{}{}
}
}
if len(unknown) > 0 {
logger.Printf("XXX: There are %d missing auth events", len(unknown))
serverReq := &fedapi.QueryJoinedHostServerNamesInRoomRequest{
RoomID: event.RoomID(),
}
serverRes := &fedapi.QueryJoinedHostServerNamesInRoomResponse{}
if err = r.FSAPI.QueryJoinedHostServerNamesInRoom(ctx, serverReq, serverRes); err != nil {
return fmt.Errorf("r.FSAPI.QueryJoinedHostServerNamesInRoom: %w", err)
}
logger.Printf("XXX: Asking servers %+v", serverRes.ServerNames)
var res gomatrixserverlib.RespEventAuth
var found bool
for _, serverName := range serverRes.ServerNames {
res, err = r.FSAPI.GetEventAuth(ctx, serverName, event.RoomID(), event.EventID())
if err != nil {
logger.WithError(err).Warnf("Failed to get event auth from federation for %q: %s", event.EventID(), err)
continue
}
logger.Printf("XXX: Server %q provided us with %d auth events", serverName, len(res.AuthEvents))
found = true
break
}
if !found {
logger.Printf("XXX: None of the %d servers provided us with auth events", len(serverRes.ServerNames))
return fmt.Errorf("no servers provided event auth")
}
for _, event := range gomatrixserverlib.ReverseTopologicalOrdering(
res.AuthEvents,
gomatrixserverlib.TopologicalOrderByAuthEvents,
) {
// If we already know about this event then we don't need to store
// it or do anything further with it.
if _, ok := known[event.EventID()]; ok {
continue
}
// Check the signatures of the event.
// TODO: It really makes sense for the federation API to be doing this,
// because then it can attempt another server if one serves up an event
// with an invalid signature. For now this will do.
if err := event.VerifyEventSignatures(ctx, r.FSAPI.KeyRing()); err != nil {
return fmt.Errorf("event.VerifyEventSignatures: %w", err)
}
// Otherwise, we need to store, and that means we need to know the
// auth event NIDs. Let's see if we can find those.
authEventNIDs := make([]types.EventNID, 0, len(event.AuthEventIDs()))
for _, eventID := range event.AuthEventIDs() {
knownEvent, ok := known[eventID]
if !ok {
return fmt.Errorf("missing auth event %s for %s", eventID, event.EventID())
}
authEventNIDs = append(authEventNIDs, knownEvent.EventNID)
}
// Let's take a note of the fact that we now know about this event.
known[event.EventID()] = nil
if err := auth.AddEvent(event); err != nil {
return fmt.Errorf("auth.AddEvent: %w", err)
}
// Check if the auth event should be rejected.
isRejected := false
if err := gomatrixserverlib.Allowed(event, auth); err != nil {
isRejected = true
logger.WithError(err).Warnf("Auth event %s rejected", event.EventID())
}
// Finally, store the event in the database.
eventNID, _, _, _, _, err := r.DB.StoreEvent(ctx, event, authEventNIDs, isRejected)
if err != nil {
return fmt.Errorf("r.DB.StoreEvent: %w", err)
}
// Now we know about this event, too.
known[event.EventID()] = &types.Event{
EventNID: eventNID,
Event: event,
}
}
}
return nil
}
/*
func (r *Inputer) checkForMissingPrevEvents(
ctx context.Context,
logger *logrus.Entry,
event *gomatrixserverlib.HeaderedEvent,
roomInfo *types.RoomInfo,
known map[string]*types.Event,
) error {
prevStates := map[string]*types.StateAtEvent{}
prevEventIDs := event.PrevEventIDs()
if len(prevEventIDs) == 0 && event.Type() != gomatrixserverlib.MRoomCreate {
return fmt.Errorf("expected to find some prev events for event type %q", event.Type())
}
for _, eventID := range prevEventIDs {
state, err := r.DB.StateAtEventIDs(ctx, []string{eventID})
if err != nil {
if _, ok := err.(types.MissingEventError); ok {
continue
}
return fmt.Errorf("r.DB.StateAtEventIDs: %w", err)
}
if len(state) == 1 {
prevStates[eventID] = &state[0]
continue
}
}
// If we know all of the states of the previous events then there is nothing more to
// do here, as the state across them will be resolved later.
if len(prevStates) == len(prevEventIDs) {
return nil
}
if r.FSAPI == nil {
return fmt.Errorf("cannot satisfy missing events without federation")
}
// Ask the federation API which servers we should ask. In theory the roomserver
// doesn't need the help of the federation API to do this because we already know
// all of the membership states, it's just that the federation API tracks this in
// a table for this purpose. TODO: Work out what makes most sense here.
serverReq := &fedapi.QueryJoinedHostServerNamesInRoomRequest{
RoomID: event.RoomID(),
}
serverRes := &fedapi.QueryJoinedHostServerNamesInRoomResponse{}
if err := r.FSAPI.QueryJoinedHostServerNamesInRoom(ctx, serverReq, serverRes); err != nil {
return fmt.Errorf("r.FSAPI.QueryJoinedHostServerNamesInRoom: %w", err)
}
// Attempt to fill in the gap using /get_missing_events
// This will either:
// - fill in the gap completely then process event `e` returning no backwards extremity
// - fail to fill in the gap and tell us to terminate the transaction err=not nil
// - fail to fill in the gap and tell us to fetch state at the new backwards extremity, and to not terminate the transaction
newEvents, err := r.getMissingEvents(ctx, logger, event, roomInfo, serverRes.ServerNames, known)
if err != nil {
return err
}
if len(newEvents) == 0 {
return fmt.Errorf("/get_missing_events returned no new events")
}
return nil
}
func (r *Inputer) getMissingEvents(
ctx context.Context,
logger *logrus.Entry,
event *gomatrixserverlib.HeaderedEvent,
roomInfo *types.RoomInfo,
servers []gomatrixserverlib.ServerName,
known map[string]*types.Event,
) (newEvents []*gomatrixserverlib.Event, err error) {
logger.Printf("XXX: get_missing_events called")
needed := gomatrixserverlib.StateNeededForAuth([]*gomatrixserverlib.Event{event.Unwrap()})
// Ask the roomserver for our current forward extremities. These will form
// the "earliest" part of the `/get_missing_events` request.
req := &api.QueryLatestEventsAndStateRequest{
RoomID: event.RoomID(),
StateToFetch: needed.Tuples(),
}
res := &api.QueryLatestEventsAndStateResponse{}
if err = r.Queryer.QueryLatestEventsAndState(ctx, req, res); err != nil {
logger.WithError(err).Warn("Failed to query latest events")
return nil, err
}
// Accumulate the event IDs of our forward extremities for use in the request.
latestEvents := make([]string, len(res.LatestEvents))
for i := range res.LatestEvents {
latestEvents[i] = res.LatestEvents[i].EventID
}
var missingResp *gomatrixserverlib.RespMissingEvents
for _, server := range servers {
logger.Printf("XXX: Calling /get_missing_events via %q", server)
var m gomatrixserverlib.RespMissingEvents
if m, err = r.FSAPI.LookupMissingEvents(ctx, server, event.RoomID(), gomatrixserverlib.MissingEvents{
Limit: 20,
EarliestEvents: latestEvents,
LatestEvents: []string{event.EventID()},
}, event.RoomVersion); err == nil {
missingResp = &m
break
} else if errors.Is(err, context.DeadlineExceeded) {
break
}
}
if missingResp == nil {
return nil, fmt.Errorf("/get_missing_events failed via all candidate servers")
}
if len(missingResp.Events) == 0 {
return nil, fmt.Errorf("/get_missing_events returned no events")
}
// 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:
// - Case A: We got pushed an event and are now fetching missing prev_events. (isInboundTxn=true)
// - Case B: We are fetching missing prev_events already and now fetching some more (isInboundTxn=false)
// In Case B, we know for sure that the event we are currently processing will not become the new forward extremity for the room,
// as it was called in response to an inbound txn which had it as a prev_event.
// In Case A, the event is a forward extremity, and could eventually become the _only_ forward extremity in the room. This is bad
// because it means we would trust the state at that event to be the state for the entire room, and allows rooms to be hijacked.
// 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.
logger.Printf("XXX: get_missing_events returned %d events", len(missingResp.Events))
newEvents = gomatrixserverlib.ReverseTopologicalOrdering(
missingResp.Events,
gomatrixserverlib.TopologicalOrderByPrevEvents,
)
for _, pe := range event.PrevEventIDs() {
hasPrevEvent := false
for _, ev := range newEvents {
if ev.EventID() == pe {
hasPrevEvent = true
break
}
}
if !hasPrevEvent {
logger.Errorf("Prev event %q is still missing after /get_missing_events", pe)
}
}
backwardExtremity := newEvents[0]
fastForwardEvents := newEvents[1:]
// Do we know about the state of the backward extremity already?
if _, err := r.DB.StateAtEventIDs(ctx, []string{backwardExtremity.EventID()}); err == nil {
// Yes, we do, so we don't need to store that event.
} else {
// No, we don't, so let's go find it.
// r.FSAPI.LookupStateIDs()
}
for _, ev := range fastForwardEvents {
if _, err := r.processRoomEvent(ctx, &api.InputRoomEvent{
Kind: api.KindOld,
Event: ev.Headered(event.RoomVersion),
AuthEventIDs: ev.AuthEventIDs(),
}); err != nil {
return nil, fmt.Errorf("r.processRoomEvent (prev event): %w", err)
}
}
return newEvents, nil
}
func (r *Inputer) lookupStateBeforeEvent(
ctx context.Context,
logger *logrus.Entry,
event *gomatrixserverlib.HeaderedEvent,
roomInfo *types.RoomInfo,
servers []gomatrixserverlib.ServerName,
) error {
knownPrevStates := map[string]types.StateAtEvent{}
unknownPrevStates := map[string]struct{}{}
neededStateEvents := map[string]struct{}{}
for _, prevEventID := range event.PrevEventIDs() {
if state, err := r.DB.StateAtEventIDs(ctx, []string{prevEventID}); err == nil && len(state) == 1 {
knownPrevStates[prevEventID] = state[0]
} else {
unknownPrevStates[prevEventID] = struct{}{}
}
}
for prevEventID := range unknownPrevStates {
stateIDs, err := r.FSAPI.LookupStateIDs(ctx, "TODO: SERVER", event.RoomID(), prevEventID)
if err != nil {
return fmt.Errorf("r.FSAPI.LookupStateIDs: %w", err)
}
events, err := r.DB.EventsFromIDs(ctx, stateIDs.StateEventIDs)
if err != nil {
return fmt.Errorf("r.DB.EventsFromIDs: %w", err)
}
for i, eventID := range stateIDs.StateEventIDs {
if events[i].Event == nil || events[i].EventNID == 0 {
neededStateEvents[eventID] = struct{}{}
}
}
if len(neededStateEvents) > (len(stateIDs.StateEventIDs) / 2) {
// More than 50% of the state events are missing, so let's just
// call `/state` instead of fetching the events individually.
state, err := r.FSAPI.LookupState(ctx, "", event.RoomID(), prevEventID, roomInfo.RoomVersion)
if err != nil {
return fmt.Errorf("r.FSAPI.LookupState: %w", err)
}
knownPrevStates[prevEventID] = types.StateAtEvent{
StateEntry: types.StateEntry{},
}
}
}
return nil
}
*/
func (r *Inputer) calculateAndSetState(
ctx context.Context,
input *api.InputRoomEvent,
roomInfo types.RoomInfo,
stateAtEvent *types.StateAtEvent,
event *gomatrixserverlib.Event,
isRejected bool,
) error {
var err error
roomState := state.NewStateResolution(r.DB, roomInfo)
if input.HasState && !isRejected {
// Check here if we think we're in the room already.
stateAtEvent.Overwrite = true
var joinEventNIDs []types.EventNID
// Request join memberships only for local users only.
if joinEventNIDs, err = r.DB.GetMembershipEventNIDsForRoom(ctx, roomInfo.RoomNID, true, true); err == nil {
// If we have no local users that are joined to the room then any state about
// the room that we have is quite possibly out of date. Therefore in that case
// we should overwrite it rather than merge it.
stateAtEvent.Overwrite = len(joinEventNIDs) == 0
}
// We've been told what the state at the event is so we don't need to calculate it.
// Check that those state events are in the database and store the state.
var entries []types.StateEntry
if entries, err = r.DB.StateEntriesForEventIDs(ctx, input.StateEventIDs); err != nil {
return fmt.Errorf("r.DB.StateEntriesForEventIDs: %w", err)
}
entries = types.DeduplicateStateEntries(entries)
if stateAtEvent.BeforeStateSnapshotNID, err = r.DB.AddState(ctx, roomInfo.RoomNID, nil, entries); err != nil {
return fmt.Errorf("r.DB.AddState: %w", err)
}
} else {
stateAtEvent.Overwrite = false
// We haven't been told what the state at the event is so we need to calculate it from the prev_events
if stateAtEvent.BeforeStateSnapshotNID, err = roomState.CalculateAndStoreStateBeforeEvent(ctx, event, isRejected); err != nil {
return fmt.Errorf("roomState.CalculateAndStoreStateBeforeEvent: %w", err)
}
}
err = r.DB.SetState(ctx, stateAtEvent.EventNID, stateAtEvent.BeforeStateSnapshotNID)
if err != nil {
return fmt.Errorf("r.DB.SetState: %w", err)
}
return nil
}