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dendrite/federationapi/routing/join.go
2022-11-15 15:05:23 +00:00

521 lines
17 KiB
Go

// Copyright 2017 New Vector Ltd
//
// 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 (
"encoding/json"
"fmt"
"net/http"
"sort"
"time"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
"github.com/sirupsen/logrus"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/setup/config"
)
// MakeJoin implements the /make_join API
func MakeJoin(
httpReq *http.Request,
request *gomatrixserverlib.FederationRequest,
cfg *config.FederationAPI,
rsAPI api.FederationRoomserverAPI,
roomID, userID string,
remoteVersions []gomatrixserverlib.RoomVersion,
) util.JSONResponse {
verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
verRes := api.QueryRoomVersionForRoomResponse{}
if err := rsAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
return util.JSONResponse{
Code: http.StatusInternalServerError,
JSON: jsonerror.InternalServerError(),
}
}
// Check that the room that the remote side is trying to join is actually
// one of the room versions that they listed in their supported ?ver= in
// the make_join URL.
// https://matrix.org/docs/spec/server_server/r0.1.3#get-matrix-federation-v1-make-join-roomid-userid
remoteSupportsVersion := false
for _, v := range remoteVersions {
if v == verRes.RoomVersion {
remoteSupportsVersion = true
break
}
}
// If it isn't, stop trying to join the room.
if !remoteSupportsVersion {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.IncompatibleRoomVersion(verRes.RoomVersion),
}
}
_, domain, err := gomatrixserverlib.SplitID('@', userID)
if err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("Invalid UserID"),
}
}
if domain != request.Origin() {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("The join must be sent by the server of the user"),
}
}
// Check if we think we are still joined to the room
inRoomReq := &api.QueryServerJoinedToRoomRequest{
ServerName: cfg.Matrix.ServerName,
RoomID: roomID,
}
inRoomRes := &api.QueryServerJoinedToRoomResponse{}
if err = rsAPI.QueryServerJoinedToRoom(httpReq.Context(), inRoomReq, inRoomRes); err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("rsAPI.QueryServerJoinedToRoom failed")
return jsonerror.InternalServerError()
}
if !inRoomRes.RoomExists {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound(fmt.Sprintf("Room ID %q was not found on this server", roomID)),
}
}
if !inRoomRes.IsInRoom {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound(fmt.Sprintf("Room ID %q has no remaining users on this server", roomID)),
}
}
// Check if the restricted join is allowed. If the room doesn't
// support restricted joins then this is effectively a no-op.
res, authorisedVia, err := checkRestrictedJoin(httpReq, rsAPI, verRes.RoomVersion, roomID, userID)
if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("checkRestrictedJoin failed")
return jsonerror.InternalServerError()
} else if res != nil {
return *res
}
// Try building an event for the server
builder := gomatrixserverlib.EventBuilder{
Sender: userID,
RoomID: roomID,
Type: "m.room.member",
StateKey: &userID,
}
content := gomatrixserverlib.MemberContent{
Membership: gomatrixserverlib.Join,
AuthorisedVia: authorisedVia,
}
if err = builder.SetContent(content); err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("builder.SetContent failed")
return jsonerror.InternalServerError()
}
identity, err := cfg.Matrix.SigningIdentityFor(request.Destination())
if err != nil {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound(
fmt.Sprintf("Server name %q does not exist", request.Destination()),
),
}
}
queryRes := api.QueryLatestEventsAndStateResponse{
RoomVersion: verRes.RoomVersion,
}
event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), &builder, cfg.Matrix, identity, time.Now(), rsAPI, &queryRes)
if err == eventutil.ErrRoomNoExists {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound("Room does not exist"),
}
} else if e, ok := err.(gomatrixserverlib.BadJSONError); ok {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(e.Error()),
}
} else if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("eventutil.BuildEvent failed")
return jsonerror.InternalServerError()
}
// Check that the join is allowed or not
stateEvents := make([]*gomatrixserverlib.Event, len(queryRes.StateEvents))
for i := range queryRes.StateEvents {
stateEvents[i] = queryRes.StateEvents[i].Event
}
provider := gomatrixserverlib.NewAuthEvents(stateEvents)
if err = gomatrixserverlib.Allowed(event.Event, &provider); err != nil {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden(err.Error()),
}
}
return util.JSONResponse{
Code: http.StatusOK,
JSON: map[string]interface{}{
"event": builder,
"room_version": verRes.RoomVersion,
},
}
}
// SendJoin implements the /send_join API
// The make-join send-join dance makes much more sense as a single
// flow so the cyclomatic complexity is high:
// nolint:gocyclo
func SendJoin(
httpReq *http.Request,
request *gomatrixserverlib.FederationRequest,
cfg *config.FederationAPI,
rsAPI api.FederationRoomserverAPI,
keys gomatrixserverlib.JSONVerifier,
roomID, eventID string,
) util.JSONResponse {
verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
verRes := api.QueryRoomVersionForRoomResponse{}
if err := rsAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("rsAPI.QueryRoomVersionForRoom failed")
return util.JSONResponse{
Code: http.StatusInternalServerError,
JSON: jsonerror.InternalServerError(),
}
}
event, err := gomatrixserverlib.NewEventFromUntrustedJSON(request.Content(), verRes.RoomVersion)
if err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("The request body could not be decoded into valid JSON: " + err.Error()),
}
}
// Check that a state key is provided.
if event.StateKey() == nil || event.StateKeyEquals("") {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("No state key was provided in the join event."),
}
}
if !event.StateKeyEquals(event.Sender()) {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("Event state key must match the event sender."),
}
}
// Check that the sender belongs to the server that is sending us
// the request. By this point we've already asserted that the sender
// and the state key are equal so we don't need to check both.
var serverName gomatrixserverlib.ServerName
if _, serverName, err = gomatrixserverlib.SplitID('@', event.Sender()); err != nil {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("The sender of the join is invalid"),
}
} else if serverName != request.Origin() {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("The sender does not match the server that originated the request"),
}
}
// Check that the room ID is correct.
if event.RoomID() != roomID {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(
fmt.Sprintf(
"The room ID in the request path (%q) must match the room ID in the join event JSON (%q)",
roomID, event.RoomID(),
),
),
}
}
// Check that the event ID is correct.
if event.EventID() != eventID {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(
fmt.Sprintf(
"The event ID in the request path (%q) must match the event ID in the join event JSON (%q)",
eventID, event.EventID(),
),
),
}
}
// Check that this is in fact a join event
membership, err := event.Membership()
if err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("missing content.membership key"),
}
}
if membership != gomatrixserverlib.Join {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("membership must be 'join'"),
}
}
// Check that the event is signed by the server sending the request.
redacted, err := gomatrixserverlib.RedactEventJSON(event.JSON(), event.Version())
if err != nil {
logrus.WithError(err).Errorf("XXX: join.go")
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON("The event JSON could not be redacted"),
}
}
verifyRequests := []gomatrixserverlib.VerifyJSONRequest{{
ServerName: serverName,
Message: redacted,
AtTS: event.OriginServerTS(),
StrictValidityChecking: true,
}}
verifyResults, err := keys.VerifyJSONs(httpReq.Context(), verifyRequests)
if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("keys.VerifyJSONs failed")
return jsonerror.InternalServerError()
}
if verifyResults[0].Error != nil {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("Signature check failed: " + verifyResults[0].Error.Error()),
}
}
// Fetch the state and auth chain. We do this before we send the events
// on, in case this fails.
var stateAndAuthChainResponse api.QueryStateAndAuthChainResponse
err = rsAPI.QueryStateAndAuthChain(httpReq.Context(), &api.QueryStateAndAuthChainRequest{
PrevEventIDs: event.PrevEventIDs(),
AuthEventIDs: event.AuthEventIDs(),
RoomID: roomID,
ResolveState: true,
}, &stateAndAuthChainResponse)
if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("rsAPI.QueryStateAndAuthChain failed")
return jsonerror.InternalServerError()
}
if !stateAndAuthChainResponse.RoomExists {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound("Room does not exist"),
}
}
if !stateAndAuthChainResponse.StateKnown {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("State not known"),
}
}
// Check if the user is already in the room. If they're already in then
// there isn't much point in sending another join event into the room.
// Also check to see if they are banned: if they are then we reject them.
alreadyJoined := false
isBanned := false
for _, se := range stateAndAuthChainResponse.StateEvents {
if !se.StateKeyEquals(*event.StateKey()) {
continue
}
if membership, merr := se.Membership(); merr == nil {
alreadyJoined = (membership == gomatrixserverlib.Join)
isBanned = (membership == gomatrixserverlib.Ban)
break
}
}
if isBanned {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("user is banned"),
}
}
// If the membership content contains a user ID for a server that is not
// ours then we should kick it back.
var memberContent gomatrixserverlib.MemberContent
if err := json.Unmarshal(event.Content(), &memberContent); err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(err.Error()),
}
}
if memberContent.AuthorisedVia != "" {
_, domain, err := gomatrixserverlib.SplitID('@', memberContent.AuthorisedVia)
if err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(fmt.Sprintf("The authorising username %q is invalid.", memberContent.AuthorisedVia)),
}
}
if domain != cfg.Matrix.ServerName {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(fmt.Sprintf("The authorising username %q does not belong to this server.", memberContent.AuthorisedVia)),
}
}
}
// Sign the membership event. This is required for restricted joins to work
// in the case that the authorised via user is one of our own users. It also
// doesn't hurt to do it even if it isn't a restricted join.
signed := event.Sign(
string(cfg.Matrix.ServerName),
cfg.Matrix.KeyID,
cfg.Matrix.PrivateKey,
)
// Send the events to the room server.
// We are responsible for notifying other servers that the user has joined
// the room, so set SendAsServer to cfg.Matrix.ServerName
if !alreadyJoined {
var response api.InputRoomEventsResponse
if err := rsAPI.InputRoomEvents(httpReq.Context(), &api.InputRoomEventsRequest{
InputRoomEvents: []api.InputRoomEvent{
{
Kind: api.KindNew,
Event: signed.Headered(stateAndAuthChainResponse.RoomVersion),
SendAsServer: string(cfg.Matrix.ServerName),
TransactionID: nil,
},
},
}, &response); err != nil {
return jsonerror.InternalAPIError(httpReq.Context(), err)
}
if response.ErrMsg != "" {
util.GetLogger(httpReq.Context()).WithField(logrus.ErrorKey, response.ErrMsg).Error("SendEvents failed")
if response.NotAllowed {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.Forbidden(response.ErrMsg),
}
}
return jsonerror.InternalServerError()
}
}
// sort events deterministically by depth (lower is earlier)
// We also do this because sytest's basic federation server isn't good at using the correct
// state if these lists are randomised, resulting in flakey tests. :(
sort.Sort(eventsByDepth(stateAndAuthChainResponse.StateEvents))
sort.Sort(eventsByDepth(stateAndAuthChainResponse.AuthChainEvents))
// https://matrix.org/docs/spec/server_server/latest#put-matrix-federation-v1-send-join-roomid-eventid
return util.JSONResponse{
Code: http.StatusOK,
JSON: gomatrixserverlib.RespSendJoin{
StateEvents: gomatrixserverlib.NewEventJSONsFromHeaderedEvents(stateAndAuthChainResponse.StateEvents),
AuthEvents: gomatrixserverlib.NewEventJSONsFromHeaderedEvents(stateAndAuthChainResponse.AuthChainEvents),
Origin: cfg.Matrix.ServerName,
Event: signed.JSON(),
},
}
}
// checkRestrictedJoin finds out whether or not we can assist in processing
// a restricted room join. If the room version does not support restricted
// joins then this function returns with no side effects. This returns three
// values:
// - an optional JSON response body (i.e. M_UNABLE_TO_AUTHORISE_JOIN) which
// should always be sent back to the client if one is specified
// - a user ID of an authorising user, typically a user that has power to
// issue invites in the room, if one has been found
// - an error if there was a problem finding out if this was allowable,
// like if the room version isn't known or a problem happened talking to
// the roomserver
func checkRestrictedJoin(
httpReq *http.Request,
rsAPI api.FederationRoomserverAPI,
roomVersion gomatrixserverlib.RoomVersion,
roomID, userID string,
) (*util.JSONResponse, string, error) {
if allowRestricted, err := roomVersion.MayAllowRestrictedJoinsInEventAuth(); err != nil {
return nil, "", err
} else if !allowRestricted {
return nil, "", nil
}
req := &api.QueryRestrictedJoinAllowedRequest{
RoomID: roomID,
UserID: userID,
}
res := &api.QueryRestrictedJoinAllowedResponse{}
if err := rsAPI.QueryRestrictedJoinAllowed(httpReq.Context(), req, res); err != nil {
return nil, "", err
}
switch {
case !res.Restricted:
// The join rules for the room don't restrict membership.
return nil, "", nil
case !res.Resident:
// The join rules restrict membership but our server isn't currently
// joined to all of the allowed rooms, so we can't actually decide
// whether or not to allow the user to join. This error code should
// tell the joining server to try joining via another resident server
// instead.
return &util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.UnableToAuthoriseJoin("This server cannot authorise the join."),
}, "", nil
case !res.Allowed:
// The join rules restrict membership, our server is in the relevant
// rooms and the user wasn't joined to join any of the allowed rooms
// and therefore can't join this room.
return &util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("You are not joined to any matching rooms."),
}, "", nil
default:
// The join rules restrict membership, our server is in the relevant
// rooms and the user was allowed to join because they belong to one
// of the allowed rooms. We now need to pick one of our own local users
// from within the room to use as the authorising user ID, so that it
// can be referred to from within the membership content.
return nil, res.AuthorisedVia, nil
}
}
type eventsByDepth []*gomatrixserverlib.HeaderedEvent
func (e eventsByDepth) Len() int {
return len(e)
}
func (e eventsByDepth) Swap(i, j int) {
e[i], e[j] = e[j], e[i]
}
func (e eventsByDepth) Less(i, j int) bool {
return e[i].Depth() < e[j].Depth()
}