package perform import ( "context" "fmt" federationSenderAPI "github.com/matrix-org/dendrite/federationsender/api" "github.com/matrix-org/dendrite/internal/config" "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/storage" "github.com/matrix-org/dendrite/roomserver/types" "github.com/matrix-org/gomatrixserverlib" log "github.com/sirupsen/logrus" ) type Inviter struct { DB storage.Database Cfg *config.RoomServer FSAPI federationSenderAPI.FederationSenderInternalAPI // TODO FIXME: Remove this RSAPI api.RoomserverInternalAPI } // nolint:gocyclo func (r *Inviter) PerformInvite( ctx context.Context, req *api.PerformInviteRequest, res *api.PerformInviteResponse, ) ([]api.OutputEvent, error) { event := req.Event if event.StateKey() == nil { return nil, fmt.Errorf("invite must be a state event") } roomID := event.RoomID() targetUserID := *event.StateKey() info, err := r.DB.RoomInfo(ctx, roomID) if err != nil { return nil, fmt.Errorf("Failed to load RoomInfo: %w", err) } log.WithFields(log.Fields{ "event_id": event.EventID(), "room_id": roomID, "room_version": req.RoomVersion, "target_user_id": targetUserID, "room_info_exists": info != nil, }).Info("processing invite event") _, domain, _ := gomatrixserverlib.SplitID('@', targetUserID) isTargetLocal := domain == r.Cfg.Matrix.ServerName isOriginLocal := event.Origin() == r.Cfg.Matrix.ServerName inviteState := req.InviteRoomState if len(inviteState) == 0 && info != nil { var is []gomatrixserverlib.InviteV2StrippedState if is, err = buildInviteStrippedState(ctx, r.DB, info, req); err == nil { inviteState = is } } if len(inviteState) == 0 { if err = event.SetUnsignedField("invite_room_state", struct{}{}); err != nil { return nil, fmt.Errorf("event.SetUnsignedField: %w", err) } } else { if err = event.SetUnsignedField("invite_room_state", inviteState); err != nil { return nil, fmt.Errorf("event.SetUnsignedField: %w", err) } } var isAlreadyJoined bool if info != nil { _, isAlreadyJoined, err = r.DB.GetMembership(ctx, info.RoomNID, *event.StateKey()) if err != nil { return nil, fmt.Errorf("r.DB.GetMembership: %w", err) } } if isAlreadyJoined { // If the user is joined to the room then that takes precedence over this // invite event. It makes little sense to move a user that is already // joined to the room into the invite state. // This could plausibly happen if an invite request raced with a join // request for a user. For example if a user was invited to a public // room and they joined the room at the same time as the invite was sent. // The other way this could plausibly happen is if an invite raced with // a kick. For example if a user was kicked from a room in error and in // response someone else in the room re-invited them then it is possible // for the invite request to race with the leave event so that the // target receives invite before it learns that it has been kicked. // There are a few ways this could be plausibly handled in the roomserver. // 1) Store the invite, but mark it as retired. That will result in the // permanent rejection of that invite event. So even if the target // user leaves the room and the invite is retransmitted it will be // ignored. However a new invite with a new event ID would still be // accepted. // 2) Silently discard the invite event. This means that if the event // was retransmitted at a later date after the target user had left // the room we would accept the invite. However since we hadn't told // the sending server that the invite had been discarded it would // have no reason to attempt to retry. // 3) Signal the sending server that the user is already joined to the // room. // For now we will implement option 2. Since in the abesence of a retry // mechanism it will be equivalent to option 1, and we don't have a // signalling mechanism to implement option 3. res.Error = &api.PerformError{ Code: api.PerformErrorNotAllowed, Msg: "User is already joined to room", } return nil, nil } if isOriginLocal { // The invite originated locally. Therefore we have a responsibility to // try and see if the user is allowed to make this invite. We can't do // this for invites coming in over federation - we have to take those on // trust. _, err = helpers.CheckAuthEvents(ctx, r.DB, event, event.AuthEventIDs()) if err != nil { log.WithError(err).WithField("event_id", event.EventID()).WithField("auth_event_ids", event.AuthEventIDs()).Error( "processInviteEvent.checkAuthEvents failed for event", ) if _, ok := err.(*gomatrixserverlib.NotAllowed); ok { res.Error = &api.PerformError{ Msg: err.Error(), Code: api.PerformErrorNotAllowed, } return nil, nil } return nil, fmt.Errorf("checkAuthEvents: %w", err) } // If the invite originated from us and the target isn't local then we // should try and send the invite over federation first. It might be // that the remote user doesn't exist, in which case we can give up // processing here. if req.SendAsServer != api.DoNotSendToOtherServers && !isTargetLocal { fsReq := &federationSenderAPI.PerformInviteRequest{ RoomVersion: req.RoomVersion, Event: event, InviteRoomState: inviteState, } fsRes := &federationSenderAPI.PerformInviteResponse{} if err = r.FSAPI.PerformInvite(ctx, fsReq, fsRes); err != nil { res.Error = &api.PerformError{ Msg: err.Error(), Code: api.PerformErrorNoOperation, } log.WithError(err).WithField("event_id", event.EventID()).Error("r.FSAPI.PerformInvite failed") return nil, nil } event = fsRes.Event } // Send the invite event to the roomserver input stream. This will // notify existing users in the room about the invite, update the // membership table and ensure that the event is ready and available // to use as an auth event when accepting the invite. inputReq := &api.InputRoomEventsRequest{ InputRoomEvents: []api.InputRoomEvent{ { Kind: api.KindNew, Event: event, AuthEventIDs: event.AuthEventIDs(), SendAsServer: req.SendAsServer, }, }, } inputRes := &api.InputRoomEventsResponse{} if err = r.RSAPI.InputRoomEvents(context.Background(), inputReq, inputRes); err != nil { return nil, fmt.Errorf("r.InputRoomEvents: %w", err) } } else { // The invite originated over federation. Process the membership // update, which will notify the sync API etc about the incoming // invite. updater, err := r.DB.MembershipUpdater(ctx, roomID, targetUserID, isTargetLocal, req.RoomVersion) if err != nil { return nil, fmt.Errorf("r.DB.MembershipUpdater: %w", err) } unwrapped := event.Unwrap() outputUpdates, err := helpers.UpdateToInviteMembership(updater, &unwrapped, nil, req.Event.RoomVersion) if err != nil { return nil, fmt.Errorf("updateToInviteMembership: %w", err) } if err = updater.Commit(); err != nil { return nil, fmt.Errorf("updater.Commit: %w", err) } return outputUpdates, nil } return nil, nil } func buildInviteStrippedState( ctx context.Context, db storage.Database, info *types.RoomInfo, input *api.PerformInviteRequest, ) ([]gomatrixserverlib.InviteV2StrippedState, error) { stateWanted := []gomatrixserverlib.StateKeyTuple{} // "If they are set on the room, at least the state for m.room.avatar, m.room.canonical_alias, m.room.join_rules, and m.room.name SHOULD be included." // https://matrix.org/docs/spec/client_server/r0.6.0#m-room-member for _, t := range []string{ gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias, gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules, "m.room.avatar", "m.room.encryption", } { stateWanted = append(stateWanted, gomatrixserverlib.StateKeyTuple{ EventType: t, StateKey: "", }) } roomState := state.NewStateResolution(db, *info) stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples( ctx, info.StateSnapshotNID, stateWanted, ) if err != nil { return nil, err } stateNIDs := []types.EventNID{} for _, stateNID := range stateEntries { stateNIDs = append(stateNIDs, stateNID.EventNID) } stateEvents, err := db.Events(ctx, stateNIDs) if err != nil { return nil, err } inviteState := []gomatrixserverlib.InviteV2StrippedState{ gomatrixserverlib.NewInviteV2StrippedState(&input.Event.Event), } stateEvents = append(stateEvents, types.Event{Event: input.Event.Unwrap()}) for _, event := range stateEvents { inviteState = append(inviteState, gomatrixserverlib.NewInviteV2StrippedState(&event.Event)) } return inviteState, nil }