dendrite/federationapi/routing/join.go
2021-11-12 13:59:57 +00:00

567 lines
19 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/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/dendrite/setup/config"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
"github.com/sirupsen/logrus"
)
// MakeJoin implements the /make_join API
func MakeJoin(
httpReq *http.Request,
request *gomatrixserverlib.FederationRequest,
cfg *config.FederationAPI,
rsAPI api.RoomserverInternalAPI,
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)),
}
}
// Try building an event for the server
builder := gomatrixserverlib.EventBuilder{
Sender: userID,
RoomID: roomID,
Type: "m.room.member",
StateKey: &userID,
}
err = builder.SetContent(map[string]interface{}{"membership": gomatrixserverlib.Join})
if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("builder.SetContent failed")
return jsonerror.InternalServerError()
}
queryRes := api.QueryLatestEventsAndStateResponse{
RoomVersion: verRes.RoomVersion,
}
event, err := eventutil.QueryAndBuildEvent(httpReq.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"),
}
} 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)
// Check the join rules. If it's a restricted join then there are special rules.
// We have to do this in two steps in order to satisfy the Complement tests. The
// first is to get the join rule itself, and the second is to unmarshal the 'allow'
// key. The tests deliberately set the 'allow' key to some nonsense values, but if
// we try to unmarshal that all in one go, the entire unmarshalling step fails,
// incorrectly leaving the room as the default join rule of 'public'.
joinRuleEvent, err := provider.JoinRules()
if err != nil {
return util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound("Failed to retrieve join rules"),
}
}
joinRule := struct {
JoinRule string `json:"join_rule"`
}{
JoinRule: gomatrixserverlib.Public, // Default join rule if not specified.
}
if joinRuleEvent != nil {
if err = json.Unmarshal(joinRuleEvent.Content(), &joinRule); err != nil {
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.Unknown("Failed to unmarshal room join rule"),
}
}
}
var joinRuleAllow struct {
Allow []gomatrixserverlib.JoinRuleContentAllowRule `json:"allow"`
}
_ = json.Unmarshal(joinRuleEvent.Content(), &joinRuleAllow)
if err = gomatrixserverlib.Allowed(event.Event, &provider); err != nil {
if joinRule.JoinRule == gomatrixserverlib.Restricted {
res := attemptMakeJoinForRestrictedMembership(
httpReq, cfg, rsAPI, &verRes, provider, &builder,
gomatrixserverlib.JoinRuleContent{
JoinRule: joinRule.JoinRule,
Allow: joinRuleAllow.Allow,
},
userID,
)
return res
}
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,
},
}
}
func attemptMakeJoinForRestrictedMembership(
httpReq *http.Request,
cfg *config.FederationAPI,
rsAPI api.RoomserverInternalAPI,
verRes *api.QueryRoomVersionForRoomResponse,
provider gomatrixserverlib.AuthEvents,
builder *gomatrixserverlib.EventBuilder,
joinRules gomatrixserverlib.JoinRuleContent,
userID string,
) util.JSONResponse {
logger := util.GetLogger(httpReq.Context()).WithField("restricted_join", userID)
foundUserInAnyRoom := false
ableToAuthoriseJoin := false
// As a last effort, see if any of the restricted join rules match.
// If so, we might be able to modify and sign the event so that it
// does pass auth.
var powerLevels gomatrixserverlib.PowerLevelContent
if powerLevelsEvent, err := provider.PowerLevels(); err != nil {
logger.WithError(err).Error("Failed to get power levels from auth events")
return util.JSONResponse{
Code: http.StatusForbidden, // TODO: StatusBadRequest
JSON: jsonerror.UnableToAuthoriseJoin("Room power levels do not exist"),
}
} else if err := json.Unmarshal(powerLevelsEvent.Content(), &powerLevels); err != nil {
logger.WithError(err).Error("Failed to unmarshal power levels")
return util.JSONResponse{
Code: http.StatusForbidden, // TODO: StatusBadRequest
JSON: jsonerror.UnableToAuthoriseJoin("Failed to unmarshal room power levels"),
}
}
// Let's see if we can validate the user being in
// any of the allowed rooms.
for _, allowed := range joinRules.Allow {
// Skip types that we don't know about.
if allowed.Type != gomatrixserverlib.MRoomMembership {
continue
}
if _, _, err := gomatrixserverlib.SplitID('!', allowed.RoomID); err != nil {
continue
}
// Ask the room server if we know about the specified room ID.
queryReq := &api.QueryMembershipsForRoomRequest{
RoomID: allowed.RoomID,
JoinedOnly: true,
}
queryRes := &api.QueryMembershipsForRoomResponse{}
if err := rsAPI.QueryMembershipsForRoom(httpReq.Context(), queryReq, queryRes); err != nil {
logger.WithError(err).Errorf("Failed to query membership for room %q", queryReq.RoomID)
continue
}
// Now have a look and see if any of the joined users match the
// user who has initiated this join.
found := false
for _, member := range queryRes.JoinEvents {
if *member.StateKey == userID {
found = true
break
}
}
// The user doesn't seem to exist in this room, try the next one.
if !found {
continue
}
// Now look through all of the join events of the other members. Our goal
// is to try and find a user from our own server that has a suitable power
// level to popuate into the `join_authorised_via_users_server` field.
foundUserInAnyRoom = true
for _, member := range queryRes.JoinEvents {
// If the user doesn't come from our own server then it's no good, try
// the next one instead.
_, domain, err := gomatrixserverlib.SplitID('@', *member.StateKey)
if err != nil {
continue
}
if domain != cfg.Matrix.ServerName {
continue
}
// We have a user who is joined to the room, so we can authorise joins.
// We will only be able to "grant" joins if any of our users have the
// power to invite other users — this flag helps us to return the right
// error code if not.
ableToAuthoriseJoin = true
// If the user has the ability to invite to the room then they are a
// suitable candidate for the `join_authorised_via_users_server`.
if powerLevels.UserLevel(*member.StateKey) >= powerLevels.Invite {
// We'll set the event content again, this time including the
// `join_authorised_via_users_server` field for the chosen user.
err := builder.SetContent(map[string]interface{}{
"membership": gomatrixserverlib.Join,
"join_authorised_via_users_server": *member.StateKey,
})
if err != nil {
logger.WithError(err).Error("builder.SetContent failed")
return jsonerror.InternalServerError()
}
// Then we'll build the event again. This is a second hit on the
// roomserver sadly, but it's a necessary evil.
queryRes := api.QueryLatestEventsAndStateResponse{
RoomVersion: verRes.RoomVersion,
}
event, err := eventutil.QueryAndBuildEvent(httpReq.Context(), builder, cfg.Matrix, time.Now(), rsAPI, &queryRes)
if err != nil {
logger.WithError(err).Error("builder.SetContent failed")
return jsonerror.InternalServerError()
}
// Sign and return the event. This is basically our seal of approval
// that other servers can use to verify that the user we put into the
// `join_authorised_via_users_server` field was actually checked
// and found by us.
return util.JSONResponse{
Code: http.StatusOK,
JSON: map[string]interface{}{
"event": event.Sign(
string(cfg.Matrix.ServerName), cfg.Matrix.KeyID, cfg.Matrix.PrivateKey,
),
"room_version": verRes.RoomVersion,
},
}
}
}
}
switch {
case ableToAuthoriseJoin && foundUserInAnyRoom:
// We found ourselves in some of the allowed rooms, but none of our
// users had a suitable power level to invite other users, so we
// don't have the ability to grant joins.
return util.JSONResponse{
Code: http.StatusForbidden, // TODO: StatusBadRequest
JSON: jsonerror.UnableToGrantJoin("None of the users from this homeserver have the power to invite"),
}
case ableToAuthoriseJoin && !foundUserInAnyRoom:
// We found ourselves in some of the allowed rooms, but none of them
// seemed to contain the joining user.
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("You are not joined to any allowed rooms"),
}
default:
// We don't seem to be joined to any of the allowed rooms, so we
// can't even check if the join is supposed to be allowed or not.
return util.JSONResponse{
Code: http.StatusForbidden, // TODO: StatusBadRequest
JSON: jsonerror.UnableToAuthoriseJoin("This homeserver isn't joined to any of the allowed rooms"),
}
}
}
// 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:
func SendJoin(
httpReq *http.Request,
request *gomatrixserverlib.FederationRequest,
cfg *config.FederationAPI,
rsAPI api.RoomserverInternalAPI,
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."),
}
}
// 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 the event is from the server sending the request.
if event.Origin() != request.Origin() {
return util.JSONResponse{
Code: http.StatusForbidden,
JSON: jsonerror.Forbidden("The join must be sent by the server it originated on"),
}
}
// 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 := event.Redact()
verifyRequests := []gomatrixserverlib.VerifyJSONRequest{{
ServerName: event.Origin(),
Message: redacted.JSON(),
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"),
}
}
// 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"),
}
}
// 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
rsAPI.InputRoomEvents(httpReq.Context(), &api.InputRoomEventsRequest{
InputRoomEvents: []api.InputRoomEvent{
{
Kind: api.KindNew,
Event: event.Headered(stateAndAuthChainResponse.RoomVersion),
AuthEventIDs: event.AuthEventIDs(),
SendAsServer: string(cfg.Matrix.ServerName),
TransactionID: nil,
},
},
}, &response)
if response.ErrMsg != "" {
util.GetLogger(httpReq.Context()).WithField(logrus.ErrorKey, response.ErrMsg).Error("SendEvents failed")
if response.NotAllowed {
return util.JSONResponse{
Code: http.StatusForbidden,
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.UnwrapEventHeaders(stateAndAuthChainResponse.StateEvents),
AuthEvents: gomatrixserverlib.UnwrapEventHeaders(stateAndAuthChainResponse.AuthChainEvents),
Origin: cfg.Matrix.ServerName,
},
}
}
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()
}