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dendrite/roomserver/internal/input/input_events.go
Kegsay 18231f25b4
Implement rejected events (#1426)
* WIP Event rejection

* Still send back errors for rejected events

Instead, discard them at the federationapi /send layer rather than
re-implementing checks at the clientapi/PerformJoin layer.

* Implement rejected events

Critically, rejected events CAN cause state resolution to happen
as it can merge forks in the DAG. This is fine, _provided_ we
do not add the rejected event when performing state resolution,
which is what this PR does. It also fixes the error handling
when NotAllowed happens, as we were checking too early and needlessly
handling NotAllowed in more than one place.

* Update test to match reality

* Modify InputRoomEvents to no longer return an error

Errors do not serialise across HTTP boundaries in polylith mode,
so instead set fields on the InputRoomEventsResponse. Add `Err()`
function to make the API shape basically the same.

* Remove redundant returns; linting

* Update blacklist
2020-09-16 13:00:52 +01:00

214 lines
7.5 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 (
"context"
"fmt"
"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/sirupsen/logrus"
)
// 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) {
// Parse and validate the event JSON
headered := input.Event
event := headered.Unwrap()
// Check that the event passes authentication checks and work out
// the numeric IDs for the auth events.
isRejected := false
authEventNIDs, rejectionErr := helpers.CheckAuthEvents(ctx, r.DB, headered, input.AuthEventIDs)
if rejectionErr != nil {
logrus.WithError(rejectionErr).WithField("event_id", event.EventID()).WithField("auth_event_ids", input.AuthEventIDs).Error("processRoomEvent.checkAuthEvents failed for event, rejecting event")
isRejected = true
}
// If we don't have a transaction ID then get one.
if input.TransactionID != nil {
tdID := input.TransactionID
eventID, err = r.DB.GetTransactionEventID(
ctx, tdID.TransactionID, tdID.SessionID, event.Sender(),
)
// On error OR event with the transaction already processed/processesing
if err != nil || eventID != "" {
return
}
}
// Store the event.
_, stateAtEvent, redactionEvent, redactedEventID, err := r.DB.StoreEvent(ctx, event, input.TransactionID, 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 {
logrus.WithFields(logrus.Fields{
"event_id": event.EventID(),
"type": event.Type(),
"room": event.RoomID(),
}).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 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 {
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 {
logrus.WithFields(logrus.Fields{
"event_id": event.EventID(),
"type": event.Type(),
"room": event.RoomID(),
}).Debug("Stored rejected event")
return event.EventID(), rejectionErr
}
if input.Kind == api.KindRewrite {
logrus.WithFields(logrus.Fields{
"event_id": event.EventID(),
"type": event.Type(),
"room": event.RoomID(),
}).Debug("Stored rewrite")
return event.EventID(), nil
}
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)
}
// 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: %w", err)
}
}
// Update the extremities of the event graph for the room
return event.EventID(), 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
}