dendrite/roomserver/internal/perform/perform_leave.go
Kegsay 18231f25b4
Implement rejected events (#1426)
* WIP Event rejection

* Still send back errors for rejected events

Instead, discard them at the federationapi /send layer rather than
re-implementing checks at the clientapi/PerformJoin layer.

* Implement rejected events

Critically, rejected events CAN cause state resolution to happen
as it can merge forks in the DAG. This is fine, _provided_ we
do not add the rejected event when performing state resolution,
which is what this PR does. It also fixes the error handling
when NotAllowed happens, as we were checking too early and needlessly
handling NotAllowed in more than one place.

* Update test to match reality

* Modify InputRoomEvents to no longer return an error

Errors do not serialise across HTTP boundaries in polylith mode,
so instead set fields on the InputRoomEventsResponse. Add `Err()`
function to make the API shape basically the same.

* Remove redundant returns; linting

* Update blacklist
2020-09-16 13:00:52 +01:00

185 lines
5.9 KiB
Go

// 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"
"strings"
fsAPI "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/storage"
"github.com/matrix-org/gomatrixserverlib"
)
type Leaver struct {
Cfg *config.RoomServer
DB storage.Database
FSAPI fsAPI.FederationSenderInternalAPI
Inputer *input.Inputer
}
// WriteOutputEvents implements OutputRoomEventWriter
func (r *Leaver) PerformLeave(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse,
) ([]api.OutputEvent, error) {
_, domain, err := gomatrixserverlib.SplitID('@', req.UserID)
if err != nil {
return nil, fmt.Errorf("Supplied user ID %q in incorrect format", req.UserID)
}
if domain != r.Cfg.Matrix.ServerName {
return nil, fmt.Errorf("User %q does not belong to this homeserver", req.UserID)
}
if strings.HasPrefix(req.RoomID, "!") {
return r.performLeaveRoomByID(ctx, req, res)
}
return nil, fmt.Errorf("Room ID %q is invalid", req.RoomID)
}
func (r *Leaver) performLeaveRoomByID(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse, // nolint:unparam
) ([]api.OutputEvent, error) {
// If there's an invite outstanding for the room then respond to
// that.
isInvitePending, senderUser, eventID, err := helpers.IsInvitePending(ctx, r.DB, req.RoomID, req.UserID)
if err == nil && isInvitePending {
return r.performRejectInvite(ctx, req, res, senderUser, eventID)
}
// There's no invite pending, so first of all we want to find out
// if the room exists and if the user is actually in it.
latestReq := api.QueryLatestEventsAndStateRequest{
RoomID: req.RoomID,
StateToFetch: []gomatrixserverlib.StateKeyTuple{
{
EventType: gomatrixserverlib.MRoomMember,
StateKey: req.UserID,
},
},
}
latestRes := api.QueryLatestEventsAndStateResponse{}
if err = helpers.QueryLatestEventsAndState(ctx, r.DB, &latestReq, &latestRes); err != nil {
return nil, err
}
if !latestRes.RoomExists {
return nil, fmt.Errorf("Room %q does not exist", req.RoomID)
}
// Now let's see if the user is in the room.
if len(latestRes.StateEvents) == 0 {
return nil, fmt.Errorf("User %q is not a member of room %q", req.UserID, req.RoomID)
}
membership, err := latestRes.StateEvents[0].Membership()
if err != nil {
return nil, fmt.Errorf("Error getting membership: %w", err)
}
if membership != gomatrixserverlib.Join {
// TODO: should be able to handle "invite" in this case too, if
// it's a case of kicking or banning or such
return nil, fmt.Errorf("User %q is not joined to the room (membership is %q)", req.UserID, membership)
}
// Prepare the template for the leave event.
userID := req.UserID
eb := gomatrixserverlib.EventBuilder{
Type: gomatrixserverlib.MRoomMember,
Sender: userID,
StateKey: &userID,
RoomID: req.RoomID,
Redacts: "",
}
if err = eb.SetContent(map[string]interface{}{"membership": "leave"}); err != nil {
return nil, fmt.Errorf("eb.SetContent: %w", err)
}
if err = eb.SetUnsigned(struct{}{}); err != nil {
return nil, fmt.Errorf("eb.SetUnsigned: %w", err)
}
// We know that the user is in the room at this point so let's build
// a leave event.
// TODO: Check what happens if the room exists on the server
// but everyone has since left. I suspect it does the wrong thing.
event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, &eb)
if err != nil {
return nil, fmt.Errorf("eventutil.BuildEvent: %w", err)
}
// Give our leave event to the roomserver input stream. The
// roomserver will process the membership change and notify
// downstream automatically.
inputReq := api.InputRoomEventsRequest{
InputRoomEvents: []api.InputRoomEvent{
{
Kind: api.KindNew,
Event: event.Headered(buildRes.RoomVersion),
AuthEventIDs: event.AuthEventIDs(),
SendAsServer: string(r.Cfg.Matrix.ServerName),
},
},
}
inputRes := api.InputRoomEventsResponse{}
r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes)
if err = inputRes.Err(); err != nil {
return nil, fmt.Errorf("r.InputRoomEvents: %w", err)
}
return nil, nil
}
func (r *Leaver) performRejectInvite(
ctx context.Context,
req *api.PerformLeaveRequest,
res *api.PerformLeaveResponse, // nolint:unparam
senderUser, eventID string,
) ([]api.OutputEvent, error) {
_, domain, err := gomatrixserverlib.SplitID('@', senderUser)
if err != nil {
return nil, fmt.Errorf("User ID %q invalid: %w", senderUser, err)
}
// Ask the federation sender to perform a federated leave for us.
leaveReq := fsAPI.PerformLeaveRequest{
RoomID: req.RoomID,
UserID: req.UserID,
ServerNames: []gomatrixserverlib.ServerName{domain},
}
leaveRes := fsAPI.PerformLeaveResponse{}
if err := r.FSAPI.PerformLeave(ctx, &leaveReq, &leaveRes); err != nil {
return nil, err
}
// Withdraw the invite, so that the sync API etc are
// notified that we rejected it.
return []api.OutputEvent{
{
Type: api.OutputTypeRetireInviteEvent,
RetireInviteEvent: &api.OutputRetireInviteEvent{
EventID: eventID,
Membership: "leave",
TargetUserID: req.UserID,
},
},
}, nil
}