diff options
Diffstat (limited to 'roomserver/internal/input/input_latest_events.go')
| -rw-r--r-- | roomserver/internal/input/input_latest_events.go | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/roomserver/internal/input/input_latest_events.go b/roomserver/internal/input/input_latest_events.go index 9ad8b042..e4c138d5 100644 --- a/roomserver/internal/input/input_latest_events.go +++ b/roomserver/internal/input/input_latest_events.go @@ -233,12 +233,19 @@ func (u *latestEventsUpdater) latestState() error { } } - // Get a list of the current latest events. This may or may not - // include the new event from the input path, depending on whether - // it is a forward extremity or not. - latestStateAtEvents := make([]types.StateAtEvent, len(u.latest)) - for i := range u.latest { - latestStateAtEvents[i] = u.latest[i].StateAtEvent + // Take the old set of extremities and the new set of extremities and + // mash them together into a list. This may or may not include the new event + // from the input path, depending on whether it became a forward extremity + // or not. We'll then run state resolution across all of them to determine + // the new current state of the room. Including the old extremities here + // ensures that new forward extremities with bad state snapshots (from + // possible malicious actors) can't completely corrupt the room state + // away from what it was before. + combinedExtremities := types.StateAtEventAndReferences(append(u.oldLatest, u.latest...)) + combinedExtremities = combinedExtremities[:util.SortAndUnique(combinedExtremities)] + latestStateAtEvents := make([]types.StateAtEvent, len(combinedExtremities)) + for i := range combinedExtremities { + latestStateAtEvents[i] = combinedExtremities[i].StateAtEvent } // Takes the NIDs of the latest events and creates a state snapshot |