dendrite/roomserver/internal/perform_invite.go

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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
}