dendrite/clientapi/routing/redaction.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 routing
import (
"context"
"net/http"
"time"
"github.com/matrix-org/dendrite/clientapi/httputil"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/setup/config"
userapi "github.com/matrix-org/dendrite/userapi/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
type redactionContent struct {
Reason string `json:"reason"`
}
type redactionResponse struct {
EventID string `json:"event_id"`
}
func SendRedaction(
req *http.Request, device *userapi.Device, roomID, eventID string, cfg *config.ClientAPI,
rsAPI roomserverAPI.RoomserverInternalAPI,
) util.JSONResponse {
resErr := checkMemberInRoom(req.Context(), rsAPI, device.UserID, roomID)
if resErr != nil {
return *resErr
}
ev := roomserverAPI.GetEvent(req.Context(), rsAPI, eventID)
if ev == nil {
return util.JSONResponse{
Code: 400,
JSON: jsonerror.NotFound("unknown event ID"), // TODO: is it ok to leak existence?
}
}
if ev.RoomID() != roomID {
return util.JSONResponse{
Code: 400,
JSON: jsonerror.NotFound("cannot redact event in another room"),
}
}
// "Users may redact their own events, and any user with a power level greater than or equal
// to the redact power level of the room may redact events there"
// https://matrix.org/docs/spec/client_server/r0.6.1#put-matrix-client-r0-rooms-roomid-redact-eventid-txnid
allowedToRedact := ev.Sender() == device.UserID
if !allowedToRedact {
plEvent := roomserverAPI.GetStateEvent(req.Context(), rsAPI, roomID, gomatrixserverlib.StateKeyTuple{
EventType: gomatrixserverlib.MRoomPowerLevels,
StateKey: "",
})
if plEvent == nil {
return util.JSONResponse{
Code: 403,
JSON: jsonerror.Forbidden("You don't have permission to redact this event, no power_levels event in this room."),
}
}
pl, err := plEvent.PowerLevels()
if err != nil {
return util.JSONResponse{
Code: 403,
JSON: jsonerror.Forbidden(
"You don't have permission to redact this event, the power_levels event for this room is malformed so auth checks cannot be performed.",
),
}
}
allowedToRedact = pl.UserLevel(device.UserID) >= pl.Redact
}
if !allowedToRedact {
return util.JSONResponse{
Code: 403,
JSON: jsonerror.Forbidden("You don't have permission to redact this event, power level too low."),
}
}
var r redactionContent
resErr = httputil.UnmarshalJSONRequest(req, &r)
if resErr != nil {
return *resErr
}
// create the new event and set all the fields we can
builder := gomatrixserverlib.EventBuilder{
Sender: device.UserID,
RoomID: roomID,
Type: gomatrixserverlib.MRoomRedaction,
Redacts: eventID,
}
err := builder.SetContent(r)
if err != nil {
util.GetLogger(req.Context()).WithError(err).Error("builder.SetContent failed")
return jsonerror.InternalServerError()
}
var queryRes api.QueryLatestEventsAndStateResponse
e, err := eventutil.QueryAndBuildEvent(req.Context(), &builder, cfg.Matrix, time.Now(), rsAPI, &queryRes)
if err == eventutil.ErrRoomNoExists {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound("Room does not exist"),
}
}
if err = roomserverAPI.SendEvents(context.Background(), rsAPI, api.KindNew, []*gomatrixserverlib.HeaderedEvent{e}, cfg.Matrix.ServerName, nil); err != nil {
util.GetLogger(req.Context()).WithError(err).Errorf("failed to SendEvents")
return jsonerror.InternalServerError()
}
return util.JSONResponse{
Code: 200,
JSON: redactionResponse{
EventID: e.EventID(),
},
}
}