dendrite/roomserver/internal/perform/perform_join.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"
"database/sql"
"errors"
"fmt"
"strings"
"time"
"github.com/getsentry/sentry-go"
"github.com/matrix-org/gomatrixserverlib"
"github.com/sirupsen/logrus"
"github.com/tidwall/gjson"
fsAPI "github.com/matrix-org/dendrite/federationapi/api"
"github.com/matrix-org/dendrite/internal/eventutil"
"github.com/matrix-org/dendrite/roomserver/api"
rsAPI "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/internal/query"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/dendrite/setup/config"
)
type Joiner struct {
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Cfg *config.RoomServer
FSAPI fsAPI.RoomserverFederationAPI
RSAPI rsAPI.RoomserverInternalAPI
DB storage.Database
Inputer *input.Inputer
Queryer *query.Queryer
}
// PerformJoin handles joining matrix rooms, including over federation by talking to the federationapi.
func (r *Joiner) PerformJoin(
ctx context.Context,
req *rsAPI.PerformJoinRequest,
res *rsAPI.PerformJoinResponse,
) error {
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logger := logrus.WithContext(ctx).WithFields(logrus.Fields{
"room_id": req.RoomIDOrAlias,
"user_id": req.UserID,
"servers": req.ServerNames,
})
logger.Info("User requested to room join")
roomID, joinedVia, err := r.performJoin(context.Background(), req)
if err != nil {
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logger.WithError(err).Error("Failed to join room")
sentry.CaptureException(err)
perr, ok := err.(*rsAPI.PerformError)
if ok {
res.Error = perr
} else {
res.Error = &rsAPI.PerformError{
Msg: err.Error(),
}
}
return nil
}
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logger.Info("User joined room successfully")
res.RoomID = roomID
res.JoinedVia = joinedVia
return nil
}
func (r *Joiner) performJoin(
ctx context.Context,
req *rsAPI.PerformJoinRequest,
) (string, gomatrixserverlib.ServerName, error) {
_, domain, err := gomatrixserverlib.SplitID('@', req.UserID)
if err != nil {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorBadRequest,
Msg: fmt.Sprintf("Supplied user ID %q in incorrect format", req.UserID),
}
}
if !r.Cfg.Matrix.IsLocalServerName(domain) {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorBadRequest,
Msg: fmt.Sprintf("User %q does not belong to this homeserver", req.UserID),
}
}
if strings.HasPrefix(req.RoomIDOrAlias, "!") {
return r.performJoinRoomByID(ctx, req)
}
if strings.HasPrefix(req.RoomIDOrAlias, "#") {
return r.performJoinRoomByAlias(ctx, req)
}
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorBadRequest,
Msg: fmt.Sprintf("Room ID or alias %q is invalid", req.RoomIDOrAlias),
}
}
func (r *Joiner) performJoinRoomByAlias(
ctx context.Context,
req *rsAPI.PerformJoinRequest,
) (string, gomatrixserverlib.ServerName, error) {
// Get the domain part of the room alias.
_, domain, err := gomatrixserverlib.SplitID('#', req.RoomIDOrAlias)
if err != nil {
return "", "", fmt.Errorf("alias %q is not in the correct format", req.RoomIDOrAlias)
}
req.ServerNames = append(req.ServerNames, domain)
// Check if this alias matches our own server configuration. If it
// doesn't then we'll need to try a federated join.
var roomID string
if !r.Cfg.Matrix.IsLocalServerName(domain) {
// The alias isn't owned by us, so we will need to try joining using
// a remote server.
dirReq := fsAPI.PerformDirectoryLookupRequest{
RoomAlias: req.RoomIDOrAlias, // the room alias to lookup
ServerName: domain, // the server to ask
}
dirRes := fsAPI.PerformDirectoryLookupResponse{}
err = r.FSAPI.PerformDirectoryLookup(ctx, &dirReq, &dirRes)
if err != nil {
logrus.WithError(err).Errorf("error looking up alias %q", req.RoomIDOrAlias)
return "", "", fmt.Errorf("looking up alias %q over federation failed: %w", req.RoomIDOrAlias, err)
}
roomID = dirRes.RoomID
req.ServerNames = append(req.ServerNames, dirRes.ServerNames...)
} else {
var getRoomReq = rsAPI.GetRoomIDForAliasRequest{
Alias: req.RoomIDOrAlias,
IncludeAppservices: true,
}
var getRoomRes = rsAPI.GetRoomIDForAliasResponse{}
// Otherwise, look up if we know this room alias locally.
err = r.RSAPI.GetRoomIDForAlias(ctx, &getRoomReq, &getRoomRes)
if err != nil {
return "", "", fmt.Errorf("lookup room alias %q failed: %w", req.RoomIDOrAlias, err)
}
roomID = getRoomRes.RoomID
}
// If the room ID is empty then we failed to look up the alias.
if roomID == "" {
return "", "", fmt.Errorf("alias %q not found", req.RoomIDOrAlias)
}
// If we do, then pluck out the room ID and continue the join.
req.RoomIDOrAlias = roomID
return r.performJoinRoomByID(ctx, req)
}
// TODO: Break this function up a bit
// nolint:gocyclo
func (r *Joiner) performJoinRoomByID(
ctx context.Context,
req *rsAPI.PerformJoinRequest,
) (string, gomatrixserverlib.ServerName, error) {
// The original client request ?server_name=... may include this HS so filter that out so we
// don't attempt to make_join with ourselves
for i := 0; i < len(req.ServerNames); i++ {
if r.Cfg.Matrix.IsLocalServerName(req.ServerNames[i]) {
// delete this entry
req.ServerNames = append(req.ServerNames[:i], req.ServerNames[i+1:]...)
i--
}
}
// Get the domain part of the room ID.
_, domain, err := gomatrixserverlib.SplitID('!', req.RoomIDOrAlias)
if err != nil {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorBadRequest,
Msg: fmt.Sprintf("Room ID %q is invalid: %s", req.RoomIDOrAlias, err),
}
}
// If the server name in the room ID isn't ours then it's a
// possible candidate for finding the room via federation. Add
// it to the list of servers to try.
if !r.Cfg.Matrix.IsLocalServerName(domain) {
req.ServerNames = append(req.ServerNames, domain)
}
// Prepare the template for the join event.
userID := req.UserID
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_, userDomain, err := r.Cfg.Matrix.SplitLocalID('@', userID)
if err != nil {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorBadRequest,
Msg: fmt.Sprintf("User ID %q is invalid: %s", userID, err),
}
}
eb := gomatrixserverlib.EventBuilder{
Type: gomatrixserverlib.MRoomMember,
Sender: userID,
StateKey: &userID,
RoomID: req.RoomIDOrAlias,
Redacts: "",
}
if err = eb.SetUnsigned(struct{}{}); err != nil {
return "", "", fmt.Errorf("eb.SetUnsigned: %w", err)
}
// It is possible for the request to include some "content" for the
// event. We'll always overwrite the "membership" key, but the rest,
// like "display_name" or "avatar_url", will be kept if supplied.
if req.Content == nil {
req.Content = map[string]interface{}{}
}
req.Content["membership"] = gomatrixserverlib.Join
if authorisedVia, aerr := r.populateAuthorisedViaUserForRestrictedJoin(ctx, req); aerr != nil {
return "", "", aerr
} else if authorisedVia != "" {
req.Content["join_authorised_via_users_server"] = authorisedVia
}
if err = eb.SetContent(req.Content); err != nil {
return "", "", fmt.Errorf("eb.SetContent: %w", err)
}
// Force a federated join if we aren't in the room and we've been
// given some server names to try joining by.
inRoomReq := &rsAPI.QueryServerJoinedToRoomRequest{
RoomID: req.RoomIDOrAlias,
}
inRoomRes := &rsAPI.QueryServerJoinedToRoomResponse{}
if err = r.Queryer.QueryServerJoinedToRoom(ctx, inRoomReq, inRoomRes); err != nil {
return "", "", fmt.Errorf("r.Queryer.QueryServerJoinedToRoom: %w", err)
}
serverInRoom := inRoomRes.IsInRoom
forceFederatedJoin := len(req.ServerNames) > 0 && !serverInRoom
// Force a federated join if we're dealing with a pending invite
// and we aren't in the room.
isInvitePending, inviteSender, _, inviteEvent, err := helpers.IsInvitePending(ctx, r.DB, req.RoomIDOrAlias, req.UserID)
if err == nil && !serverInRoom && isInvitePending {
_, inviterDomain, ierr := gomatrixserverlib.SplitID('@', inviteSender)
if ierr != nil {
return "", "", fmt.Errorf("gomatrixserverlib.SplitID: %w", err)
}
// If we were invited by someone from another server then we can
// assume they are in the room so we can join via them.
if !r.Cfg.Matrix.IsLocalServerName(inviterDomain) {
req.ServerNames = append(req.ServerNames, inviterDomain)
forceFederatedJoin = true
memberEvent := gjson.Parse(string(inviteEvent.JSON()))
// only set unsigned if we've got a content.membership, which we _should_
if memberEvent.Get("content.membership").Exists() {
req.Unsigned = map[string]interface{}{
"prev_sender": memberEvent.Get("sender").Str,
"prev_content": map[string]interface{}{
"is_direct": memberEvent.Get("content.is_direct").Bool(),
"membership": memberEvent.Get("content.membership").Str,
},
}
}
}
}
// If a guest is trying to join a room, check that the room has a m.room.guest_access event
if req.IsGuest {
var guestAccessEvent *gomatrixserverlib.HeaderedEvent
guestAccess := "forbidden"
guestAccessEvent, err = r.DB.GetStateEvent(ctx, req.RoomIDOrAlias, gomatrixserverlib.MRoomGuestAccess, "")
if (err != nil && !errors.Is(err, sql.ErrNoRows)) || guestAccessEvent == nil {
logrus.WithError(err).Warn("unable to get m.room.guest_access event, defaulting to 'forbidden'")
}
if guestAccessEvent != nil {
guestAccess = gjson.GetBytes(guestAccessEvent.Content(), "guest_access").String()
}
// Servers MUST only allow guest users to join rooms if the m.room.guest_access state event
// is present on the room and has the guest_access value can_join.
if guestAccess != "can_join" {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorNotAllowed,
Msg: "Guest access is forbidden",
}
}
}
// If we should do a forced federated join then do that.
var joinedVia gomatrixserverlib.ServerName
if forceFederatedJoin {
joinedVia, err = r.performFederatedJoinRoomByID(ctx, req)
return req.RoomIDOrAlias, joinedVia, err
}
// Try to construct an actual join event from the template.
// If this succeeds then it is a sign that the room already exists
// locally on the homeserver.
// TODO: Check what happens if the room exists on the server
// but everyone has since left. I suspect it does the wrong thing.
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event, buildRes, err := buildEvent(ctx, r.DB, r.Cfg.Matrix, userDomain, &eb)
switch err {
case nil:
// The room join is local. Send the new join event into the
// roomserver. First of all check that the user isn't already
// a member of the room. This is best-effort (as in we won't
// fail if we can't find the existing membership) because there
// is really no harm in just sending another membership event.
membershipReq := &api.QueryMembershipForUserRequest{
RoomID: req.RoomIDOrAlias,
UserID: userID,
}
membershipRes := &api.QueryMembershipForUserResponse{}
_ = r.Queryer.QueryMembershipForUser(ctx, membershipReq, membershipRes)
// If we haven't already joined the room then send an event
// into the room changing our membership status.
if !membershipRes.RoomExists || !membershipRes.IsInRoom {
inputReq := rsAPI.InputRoomEventsRequest{
InputRoomEvents: []rsAPI.InputRoomEvent{
{
Kind: rsAPI.KindNew,
Event: event.Headered(buildRes.RoomVersion),
SendAsServer: string(userDomain),
},
},
}
inputRes := rsAPI.InputRoomEventsResponse{}
if err = r.Inputer.InputRoomEvents(ctx, &inputReq, &inputRes); err != nil {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorNoOperation,
Msg: fmt.Sprintf("InputRoomEvents failed: %s", err),
}
}
if err = inputRes.Err(); err != nil {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorNotAllowed,
Msg: fmt.Sprintf("InputRoomEvents auth failed: %s", err),
}
}
}
case eventutil.ErrRoomNoExists:
// The room doesn't exist locally. If the room ID looks like it should
// be ours then this probably means that we've nuked our database at
// some point.
if r.Cfg.Matrix.IsLocalServerName(domain) {
// If there are no more server names to try then give up here.
// Otherwise we'll try a federated join as normal, since it's quite
// possible that the room still exists on other servers.
if len(req.ServerNames) == 0 {
return "", "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorNoRoom,
Msg: fmt.Sprintf("room ID %q does not exist", req.RoomIDOrAlias),
}
}
}
// Perform a federated room join.
joinedVia, err = r.performFederatedJoinRoomByID(ctx, req)
return req.RoomIDOrAlias, joinedVia, err
default:
// Something else went wrong.
return "", "", fmt.Errorf("error joining local room: %q", err)
}
// By this point, if req.RoomIDOrAlias contained an alias, then
// it will have been overwritten with a room ID by performJoinRoomByAlias.
// We should now include this in the response so that the CS API can
// return the right room ID.
return req.RoomIDOrAlias, userDomain, nil
}
func (r *Joiner) performFederatedJoinRoomByID(
ctx context.Context,
req *rsAPI.PerformJoinRequest,
) (gomatrixserverlib.ServerName, error) {
// Try joining by all of the supplied server names.
fedReq := fsAPI.PerformJoinRequest{
RoomID: req.RoomIDOrAlias, // the room ID to try and join
UserID: req.UserID, // the user ID joining the room
ServerNames: req.ServerNames, // the server to try joining with
Content: req.Content, // the membership event content
Unsigned: req.Unsigned, // the unsigned event content, if any
}
fedRes := fsAPI.PerformJoinResponse{}
r.FSAPI.PerformJoin(ctx, &fedReq, &fedRes)
if fedRes.LastError != nil {
return "", &rsAPI.PerformError{
Code: rsAPI.PerformErrRemote,
Msg: fedRes.LastError.Message,
RemoteCode: fedRes.LastError.Code,
}
}
return fedRes.JoinedVia, nil
}
func (r *Joiner) populateAuthorisedViaUserForRestrictedJoin(
ctx context.Context,
joinReq *rsAPI.PerformJoinRequest,
) (string, error) {
req := &api.QueryRestrictedJoinAllowedRequest{
UserID: joinReq.UserID,
RoomID: joinReq.RoomIDOrAlias,
}
res := &api.QueryRestrictedJoinAllowedResponse{}
if err := r.Queryer.QueryRestrictedJoinAllowed(ctx, req, res); err != nil {
return "", fmt.Errorf("r.Queryer.QueryRestrictedJoinAllowed: %w", err)
}
if !res.Restricted {
return "", nil
}
if !res.Resident {
return "", nil
}
if !res.Allowed {
return "", &rsAPI.PerformError{
Code: rsAPI.PerformErrorNotAllowed,
Msg: fmt.Sprintf("The join to room %s was not allowed.", joinReq.RoomIDOrAlias),
}
}
return res.AuthorisedVia, nil
}
func buildEvent(
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ctx context.Context, db storage.Database, cfg *config.Global,
senderDomain gomatrixserverlib.ServerName,
builder *gomatrixserverlib.EventBuilder,
) (*gomatrixserverlib.HeaderedEvent, *rsAPI.QueryLatestEventsAndStateResponse, error) {
eventsNeeded, err := gomatrixserverlib.StateNeededForEventBuilder(builder)
if err != nil {
return nil, nil, fmt.Errorf("gomatrixserverlib.StateNeededForEventBuilder: %w", err)
}
if len(eventsNeeded.Tuples()) == 0 {
return nil, nil, errors.New("expecting state tuples for event builder, got none")
}
var queryRes rsAPI.QueryLatestEventsAndStateResponse
err = helpers.QueryLatestEventsAndState(ctx, db, &rsAPI.QueryLatestEventsAndStateRequest{
RoomID: builder.RoomID,
StateToFetch: eventsNeeded.Tuples(),
}, &queryRes)
if err != nil {
switch err.(type) {
case types.MissingStateError:
// We know something about the room but the state seems to be
// insufficient to actually build a new event, so in effect we
// had might as well treat the room as if it doesn't exist.
return nil, nil, eventutil.ErrRoomNoExists
default:
return nil, nil, fmt.Errorf("QueryLatestEventsAndState: %w", err)
}
}
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identity, err := cfg.SigningIdentityFor(senderDomain)
if err != nil {
return nil, nil, err
}
ev, err := eventutil.BuildEvent(ctx, builder, cfg, identity, time.Now(), &eventsNeeded, &queryRes)
if err != nil {
return nil, nil, err
}
return ev, &queryRes, nil
}