package internal import ( "context" "errors" "fmt" "github.com/matrix-org/dendrite/internal/sqlutil" "github.com/matrix-org/dendrite/roomserver/api" "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" ) // PerformInvite handles inviting to matrix rooms, including over federation by talking to the federationsender. func (r *RoomserverInternalAPI) PerformInvite( ctx context.Context, req *api.PerformInviteRequest, res *api.PerformInviteResponse, ) { err := r.performInvite(ctx, req) if err != nil { perr, ok := err.(*api.PerformError) if ok { res.Error = perr } else { res.Error = &api.PerformError{ Msg: err.Error(), } } } } func (r *RoomserverInternalAPI) performInvite(ctx context.Context, req *api.PerformInviteRequest, ) error { loopback, err := r.processInviteEvent(ctx, r, req) if err != nil { return err } // The processInviteEvent function can optionally return a // loopback room event containing the invite, for local invites. // If it does, we should process it with the room events below. if loopback != nil { var loopbackRes api.InputRoomEventsResponse err := r.InputRoomEvents(ctx, &api.InputRoomEventsRequest{ InputRoomEvents: []api.InputRoomEvent{*loopback}, }, &loopbackRes) if err != nil { return err } } return nil } // nolint:gocyclo func (r *RoomserverInternalAPI) processInviteEvent( ctx context.Context, ow *RoomserverInternalAPI, input *api.PerformInviteRequest, ) (*api.InputRoomEvent, error) { if input.Event.StateKey() == nil { return nil, fmt.Errorf("invite must be a state event") } roomID := input.Event.RoomID() targetUserID := *input.Event.StateKey() log.WithFields(log.Fields{ "event_id": input.Event.EventID(), "room_id": roomID, "room_version": input.RoomVersion, "target_user_id": targetUserID, }).Info("processing invite event") _, domain, _ := gomatrixserverlib.SplitID('@', targetUserID) isTargetLocalUser := domain == r.Cfg.Matrix.ServerName updater, err := r.DB.MembershipUpdater(ctx, roomID, targetUserID, isTargetLocalUser, input.RoomVersion) if err != nil { return nil, err } succeeded := false defer func() { txerr := sqlutil.EndTransaction(updater, &succeeded) if err == nil && txerr != nil { err = txerr } }() if updater.IsJoin() { // 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. return nil, &api.PerformError{ Code: api.PerformErrorNoOperation, Msg: "user is already joined to room", } } // Normally, with a federated invite, the federation sender would do // the /v2/invite request (in which the remote server signs the invite) // and then the signed event gets sent back to the roomserver as an input // event. When the invite is local, we don't interact with the federation // sender therefore we need to generate the loopback invite event for // the room ourselves. loopback, err := localInviteLoopback(ow, input) if err != nil { return nil, err } event := input.Event.Unwrap() // check that the user is allowed to do this. We can only do this check if it is // a local invite as we have the auth events, else we have to take it on trust. if loopback != nil { _, err = checkAuthEvents(ctx, r.DB, input.Event, input.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 { return nil, &api.PerformError{ Msg: err.Error(), Code: api.PerformErrorNotAllowed, } } return nil, err } } if len(input.InviteRoomState) > 0 { // If we were supplied with some invite room state already (which is // most likely to be if the event came in over federation) then use // that. if err = event.SetUnsignedField("invite_room_state", input.InviteRoomState); err != nil { return nil, err } } else { // There's no invite room state, so let's have a go at building it // up from local data (which is most likely to be if the event came // from the CS API). If we know about the room then we can insert // the invite room state, if we don't then we just fail quietly. if irs, ierr := buildInviteStrippedState(ctx, r.DB, input); ierr == nil { if err = event.SetUnsignedField("invite_room_state", irs); err != nil { return nil, err } } else { log.WithError(ierr).Error("failed to build invite stripped state") // still set the field else synapse deployments don't process the invite if err = event.SetUnsignedField("invite_room_state", struct{}{}); err != nil { return nil, err } } } outputUpdates, err := updateToInviteMembership(updater, &event, nil, input.Event.RoomVersion) if err != nil { return nil, err } if err = ow.WriteOutputEvents(roomID, outputUpdates); err != nil { return nil, err } succeeded = true return loopback, nil } func localInviteLoopback( ow *RoomserverInternalAPI, input *api.PerformInviteRequest, ) (ire *api.InputRoomEvent, err error) { if input.Event.StateKey() == nil { return nil, errors.New("no state key on invite event") } ourServerName := string(ow.Cfg.Matrix.ServerName) _, theirServerName, err := gomatrixserverlib.SplitID('@', *input.Event.StateKey()) if err != nil { return nil, err } // Check if the invite originated locally and is destined locally. if input.Event.Origin() == ow.Cfg.Matrix.ServerName && string(theirServerName) == ourServerName { rsEvent := input.Event.Sign( ourServerName, ow.Cfg.Matrix.KeyID, ow.Cfg.Matrix.PrivateKey, ).Headered(input.RoomVersion) ire = &api.InputRoomEvent{ Kind: api.KindNew, Event: rsEvent, AuthEventIDs: rsEvent.AuthEventIDs(), SendAsServer: ourServerName, TransactionID: nil, } } return ire, nil } func buildInviteStrippedState( ctx context.Context, db storage.Database, input *api.PerformInviteRequest, ) ([]gomatrixserverlib.InviteV2StrippedState, error) { roomNID, err := db.RoomNID(ctx, input.Event.RoomID()) if err != nil || roomNID == 0 { return nil, fmt.Errorf("room %q unknown", input.Event.RoomID()) } 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", } { stateWanted = append(stateWanted, gomatrixserverlib.StateKeyTuple{ EventType: t, StateKey: "", }) } _, currentStateSnapshotNID, _, err := db.LatestEventIDs(ctx, roomNID) if err != nil { return nil, err } roomState := state.NewStateResolution(db) stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples( ctx, currentStateSnapshotNID, 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 }