dendrite/roomserver/internal/perform/perform_invite.go

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// Copyright 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 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/internal/input"
"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
Inputer *input.Inputer
}
// 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",
)
res.Error = &api.PerformError{
Msg: err.Error(),
Code: api.PerformErrorNotAllowed,
}
}
// 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.PerformErrorNotAllowed,
}
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{}
r.Inputer.InputRoomEvents(context.Background(), inputReq, inputRes)
if err = inputRes.Err(); err != nil {
res.Error = &api.PerformError{
Msg: fmt.Sprintf("r.InputRoomEvents: %s", err.Error()),
Code: api.PerformErrorNotAllowed,
}
log.WithError(err).WithField("event_id", event.EventID()).Error("r.InputRoomEvents failed")
return nil, nil
}
} 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
}