mirror of
https://github.com/matrix-org/dendrite
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* Remove ServerACLs from the current state server Functionality moved to roomserver * Nothing to see here, move along
828 lines
32 KiB
Go
828 lines
32 KiB
Go
// Copyright 2017 Vector Creations Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package routing
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import (
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"context"
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"encoding/json"
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"fmt"
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"net/http"
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"github.com/matrix-org/dendrite/clientapi/jsonerror"
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eduserverAPI "github.com/matrix-org/dendrite/eduserver/api"
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"github.com/matrix-org/dendrite/internal/config"
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keyapi "github.com/matrix-org/dendrite/keyserver/api"
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"github.com/matrix-org/dendrite/roomserver/api"
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"github.com/matrix-org/gomatrixserverlib"
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"github.com/matrix-org/util"
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"github.com/sirupsen/logrus"
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)
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// Send implements /_matrix/federation/v1/send/{txnID}
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func Send(
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httpReq *http.Request,
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request *gomatrixserverlib.FederationRequest,
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txnID gomatrixserverlib.TransactionID,
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cfg *config.FederationAPI,
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rsAPI api.RoomserverInternalAPI,
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eduAPI eduserverAPI.EDUServerInputAPI,
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keyAPI keyapi.KeyInternalAPI,
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keys gomatrixserverlib.JSONVerifier,
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federation *gomatrixserverlib.FederationClient,
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) util.JSONResponse {
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t := txnReq{
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context: httpReq.Context(),
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rsAPI: rsAPI,
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eduAPI: eduAPI,
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keys: keys,
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federation: federation,
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haveEvents: make(map[string]*gomatrixserverlib.HeaderedEvent),
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newEvents: make(map[string]bool),
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keyAPI: keyAPI,
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}
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var txnEvents struct {
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PDUs []json.RawMessage `json:"pdus"`
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EDUs []gomatrixserverlib.EDU `json:"edus"`
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}
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if err := json.Unmarshal(request.Content(), &txnEvents); err != nil {
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return util.JSONResponse{
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Code: http.StatusBadRequest,
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JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
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}
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}
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// Transactions are limited in size; they can have at most 50 PDUs and 100 EDUs.
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// https://matrix.org/docs/spec/server_server/latest#transactions
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if len(txnEvents.PDUs) > 50 || len(txnEvents.EDUs) > 100 {
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return util.JSONResponse{
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Code: http.StatusBadRequest,
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JSON: jsonerror.BadJSON("max 50 pdus / 100 edus"),
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}
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}
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// TODO: Really we should have a function to convert FederationRequest to txnReq
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t.PDUs = txnEvents.PDUs
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t.EDUs = txnEvents.EDUs
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t.Origin = request.Origin()
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t.TransactionID = txnID
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t.Destination = cfg.Matrix.ServerName
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util.GetLogger(httpReq.Context()).Infof("Received transaction %q containing %d PDUs, %d EDUs", txnID, len(t.PDUs), len(t.EDUs))
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resp, jsonErr := t.processTransaction()
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if jsonErr != nil {
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util.GetLogger(httpReq.Context()).WithField("jsonErr", jsonErr).Error("t.processTransaction failed")
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return *jsonErr
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}
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// https://matrix.org/docs/spec/server_server/r0.1.3#put-matrix-federation-v1-send-txnid
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// Status code 200:
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// The result of processing the transaction. The server is to use this response
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// even in the event of one or more PDUs failing to be processed.
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return util.JSONResponse{
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Code: http.StatusOK,
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JSON: resp,
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}
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}
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type txnReq struct {
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gomatrixserverlib.Transaction
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context context.Context
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rsAPI api.RoomserverInternalAPI
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eduAPI eduserverAPI.EDUServerInputAPI
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keyAPI keyapi.KeyInternalAPI
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keys gomatrixserverlib.JSONVerifier
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federation txnFederationClient
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// local cache of events for auth checks, etc - this may include events
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// which the roomserver is unaware of.
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haveEvents map[string]*gomatrixserverlib.HeaderedEvent
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// new events which the roomserver does not know about
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newEvents map[string]bool
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}
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// A subset of FederationClient functionality that txn requires. Useful for testing.
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type txnFederationClient interface {
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LookupState(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
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res gomatrixserverlib.RespState, err error,
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)
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LookupStateIDs(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, eventID string) (res gomatrixserverlib.RespStateIDs, err error)
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GetEvent(ctx context.Context, s gomatrixserverlib.ServerName, eventID string) (res gomatrixserverlib.Transaction, err error)
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LookupMissingEvents(ctx context.Context, s gomatrixserverlib.ServerName, roomID string, missing gomatrixserverlib.MissingEvents,
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roomVersion gomatrixserverlib.RoomVersion) (res gomatrixserverlib.RespMissingEvents, err error)
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}
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func (t *txnReq) processTransaction() (*gomatrixserverlib.RespSend, *util.JSONResponse) {
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results := make(map[string]gomatrixserverlib.PDUResult)
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pdus := []gomatrixserverlib.HeaderedEvent{}
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for _, pdu := range t.PDUs {
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var header struct {
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RoomID string `json:"room_id"`
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}
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if err := json.Unmarshal(pdu, &header); err != nil {
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util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to extract room ID from event")
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// We don't know the event ID at this point so we can't return the
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// failure in the PDU results
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continue
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}
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verReq := api.QueryRoomVersionForRoomRequest{RoomID: header.RoomID}
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verRes := api.QueryRoomVersionForRoomResponse{}
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if err := t.rsAPI.QueryRoomVersionForRoom(t.context, &verReq, &verRes); err != nil {
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util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to query room version for room", verReq.RoomID)
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// We don't know the event ID at this point so we can't return the
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// failure in the PDU results
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continue
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}
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event, err := gomatrixserverlib.NewEventFromUntrustedJSON(pdu, verRes.RoomVersion)
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if err != nil {
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if _, ok := err.(gomatrixserverlib.BadJSONError); ok {
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// Room version 6 states that homeservers should strictly enforce canonical JSON
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// on PDUs.
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//
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// This enforces that the entire transaction is rejected if a single bad PDU is
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// sent. It is unclear if this is the correct behaviour or not.
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//
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// See https://github.com/matrix-org/synapse/issues/7543
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return nil, &util.JSONResponse{
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Code: 400,
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JSON: jsonerror.BadJSON("PDU contains bad JSON"),
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}
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}
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util.GetLogger(t.context).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %s", string(pdu))
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continue
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}
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if api.IsServerBannedFromRoom(t.context, t.rsAPI, event.RoomID(), t.Origin) {
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results[event.EventID()] = gomatrixserverlib.PDUResult{
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Error: "Forbidden by server ACLs",
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}
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continue
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}
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if err = gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
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util.GetLogger(t.context).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
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results[event.EventID()] = gomatrixserverlib.PDUResult{
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Error: err.Error(),
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}
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continue
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}
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pdus = append(pdus, event.Headered(verRes.RoomVersion))
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}
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// Process the events.
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for _, e := range pdus {
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if err := t.processEvent(e.Unwrap(), true); err != nil {
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// If the error is due to the event itself being bad then we skip
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// it and move onto the next event. We report an error so that the
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// sender knows that we have skipped processing it.
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//
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// However if the event is due to a temporary failure in our server
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// such as a database being unavailable then we should bail, and
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// hope that the sender will retry when we are feeling better.
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//
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// It is uncertain what we should do if an event fails because
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// we failed to fetch more information from the sending server.
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// For example if a request to /state fails.
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// If we skip the event then we risk missing the event until we
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// receive another event referencing it.
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// If we bail and stop processing then we risk wedging incoming
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// transactions from that server forever.
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if isProcessingErrorFatal(err) {
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// Any other error should be the result of a temporary error in
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// our server so we should bail processing the transaction entirely.
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util.GetLogger(t.context).Warnf("Processing %s failed fatally: %s", e.EventID(), err)
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jsonErr := util.ErrorResponse(err)
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return nil, &jsonErr
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} else {
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// Auth errors mean the event is 'rejected' which have to be silent to appease sytest
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_, rejected := err.(*gomatrixserverlib.NotAllowed)
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errMsg := err.Error()
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if rejected {
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errMsg = ""
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}
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util.GetLogger(t.context).WithError(err).WithField("event_id", e.EventID()).WithField("rejected", rejected).Warn(
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"Failed to process incoming federation event, skipping",
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)
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results[e.EventID()] = gomatrixserverlib.PDUResult{
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Error: errMsg,
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}
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}
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} else {
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results[e.EventID()] = gomatrixserverlib.PDUResult{}
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}
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}
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t.processEDUs(t.EDUs)
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if c := len(results); c > 0 {
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util.GetLogger(t.context).Infof("Processed %d PDUs from transaction %q", c, t.TransactionID)
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}
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return &gomatrixserverlib.RespSend{PDUs: results}, nil
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}
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// isProcessingErrorFatal returns true if the error is really bad and
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// we should stop processing the transaction, and returns false if it
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// is just some less serious error about a specific event.
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func isProcessingErrorFatal(err error) bool {
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switch err.(type) {
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case roomNotFoundError:
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case *gomatrixserverlib.NotAllowed:
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case missingPrevEventsError:
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default:
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switch err {
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case context.Canceled:
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case context.DeadlineExceeded:
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default:
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return true
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}
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}
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return false
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}
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type roomNotFoundError struct {
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roomID string
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}
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type unmarshalError struct {
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err error
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}
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type verifySigError struct {
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eventID string
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err error
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}
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type missingPrevEventsError struct {
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eventID string
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err error
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}
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func (e roomNotFoundError) Error() string { return fmt.Sprintf("room %q not found", e.roomID) }
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func (e unmarshalError) Error() string { return fmt.Sprintf("unable to parse event: %s", e.err) }
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func (e verifySigError) Error() string {
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return fmt.Sprintf("unable to verify signature of event %q: %s", e.eventID, e.err)
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}
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func (e missingPrevEventsError) Error() string {
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return fmt.Sprintf("unable to get prev_events for event %q: %s", e.eventID, e.err)
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}
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func (t *txnReq) haveEventIDs() map[string]bool {
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result := make(map[string]bool, len(t.haveEvents))
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for eventID := range t.haveEvents {
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if t.newEvents[eventID] {
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continue
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}
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result[eventID] = true
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}
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return result
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}
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func (t *txnReq) processEDUs(edus []gomatrixserverlib.EDU) {
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for _, e := range edus {
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switch e.Type {
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case gomatrixserverlib.MTyping:
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// https://matrix.org/docs/spec/server_server/latest#typing-notifications
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var typingPayload struct {
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RoomID string `json:"room_id"`
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UserID string `json:"user_id"`
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Typing bool `json:"typing"`
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}
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if err := json.Unmarshal(e.Content, &typingPayload); err != nil {
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util.GetLogger(t.context).WithError(err).Error("Failed to unmarshal typing event")
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continue
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}
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if err := eduserverAPI.SendTyping(t.context, t.eduAPI, typingPayload.UserID, typingPayload.RoomID, typingPayload.Typing, 30*1000); err != nil {
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util.GetLogger(t.context).WithError(err).Error("Failed to send typing event to edu server")
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}
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case gomatrixserverlib.MDirectToDevice:
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// https://matrix.org/docs/spec/server_server/r0.1.3#m-direct-to-device-schema
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var directPayload gomatrixserverlib.ToDeviceMessage
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if err := json.Unmarshal(e.Content, &directPayload); err != nil {
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util.GetLogger(t.context).WithError(err).Error("Failed to unmarshal send-to-device events")
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continue
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}
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for userID, byUser := range directPayload.Messages {
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for deviceID, message := range byUser {
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// TODO: check that the user and the device actually exist here
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if err := eduserverAPI.SendToDevice(t.context, t.eduAPI, directPayload.Sender, userID, deviceID, directPayload.Type, message); err != nil {
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util.GetLogger(t.context).WithError(err).WithFields(logrus.Fields{
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"sender": directPayload.Sender,
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"user_id": userID,
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"device_id": deviceID,
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}).Error("Failed to send send-to-device event to edu server")
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}
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}
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}
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case gomatrixserverlib.MDeviceListUpdate:
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t.processDeviceListUpdate(e)
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default:
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util.GetLogger(t.context).WithField("type", e.Type).Debug("Unhandled EDU")
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}
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}
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}
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func (t *txnReq) processDeviceListUpdate(e gomatrixserverlib.EDU) {
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var payload gomatrixserverlib.DeviceListUpdateEvent
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if err := json.Unmarshal(e.Content, &payload); err != nil {
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util.GetLogger(t.context).WithError(err).Error("Failed to unmarshal device list update event")
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return
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}
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var inputRes keyapi.InputDeviceListUpdateResponse
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t.keyAPI.InputDeviceListUpdate(context.Background(), &keyapi.InputDeviceListUpdateRequest{
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Event: payload,
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}, &inputRes)
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if inputRes.Error != nil {
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util.GetLogger(t.context).WithError(inputRes.Error).WithField("user_id", payload.UserID).Error("failed to InputDeviceListUpdate")
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}
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}
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func (t *txnReq) processEvent(e gomatrixserverlib.Event, isInboundTxn bool) error {
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prevEventIDs := e.PrevEventIDs()
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// Fetch the state needed to authenticate the event.
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needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{e})
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stateReq := api.QueryStateAfterEventsRequest{
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RoomID: e.RoomID(),
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PrevEventIDs: prevEventIDs,
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StateToFetch: needed.Tuples(),
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}
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var stateResp api.QueryStateAfterEventsResponse
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if err := t.rsAPI.QueryStateAfterEvents(t.context, &stateReq, &stateResp); err != nil {
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return err
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}
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if !stateResp.RoomExists {
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// TODO: When synapse receives a message for a room it is not in it
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// asks the remote server for the state of the room so that it can
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// check if the remote server knows of a join "m.room.member" event
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// that this server is unaware of.
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// However generally speaking we should reject events for rooms we
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// aren't a member of.
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return roomNotFoundError{e.RoomID()}
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}
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if !stateResp.PrevEventsExist {
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return t.processEventWithMissingState(e, stateResp.RoomVersion, isInboundTxn)
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}
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// Check that the event is allowed by the state at the event.
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if err := checkAllowedByState(e, gomatrixserverlib.UnwrapEventHeaders(stateResp.StateEvents)); err != nil {
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return err
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}
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// pass the event to the roomserver
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return api.SendEvents(
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t.context, t.rsAPI,
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[]gomatrixserverlib.HeaderedEvent{
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e.Headered(stateResp.RoomVersion),
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},
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api.DoNotSendToOtherServers,
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nil,
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)
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}
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func checkAllowedByState(e gomatrixserverlib.Event, stateEvents []gomatrixserverlib.Event) error {
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authUsingState := gomatrixserverlib.NewAuthEvents(nil)
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for i := range stateEvents {
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err := authUsingState.AddEvent(&stateEvents[i])
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if err != nil {
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return err
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}
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}
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return gomatrixserverlib.Allowed(e, &authUsingState)
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}
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func (t *txnReq) processEventWithMissingState(e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion, isInboundTxn bool) error {
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// We are missing the previous events for this events.
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// This means that there is a gap in our view of the history of the
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// room. There two ways that we can handle such a gap:
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// 1) We can fill in the gap using /get_missing_events
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// 2) We can leave the gap and request the state of the room at
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// this event from the remote server using either /state_ids
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// or /state.
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// Synapse will attempt to do 1 and if that fails or if the gap is
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// too large then it will attempt 2.
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// Synapse will use /state_ids if possible since usually the state
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// is largely unchanged and it is more efficient to fetch a list of
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// event ids and then use /event to fetch the individual events.
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// However not all version of synapse support /state_ids so you may
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// need to fallback to /state.
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// Attempt to fill in the gap using /get_missing_events
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// This will either:
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// - fill in the gap completely then process event `e` returning no backwards extremity
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// - fail to fill in the gap and tell us to terminate the transaction err=not nil
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// - fail to fill in the gap and tell us to fetch state at the new backwards extremity, and to not terminate the transaction
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backwardsExtremity, err := t.getMissingEvents(e, roomVersion, isInboundTxn)
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if err != nil {
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return err
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}
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if backwardsExtremity == nil {
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// we filled in the gap!
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return nil
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}
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// at this point we know we're going to have a gap: we need to work out the room state at the new backwards extremity.
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// security: we have to do state resolution on the new backwards extremity (TODO: WHY)
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// Therefore, we cannot just query /state_ids with this event to get the state before. Instead, we need to query
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// the state AFTER all the prev_events for this event, then apply state resolution to that to get the state before the event.
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var states []*gomatrixserverlib.RespState
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needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{*backwardsExtremity}).Tuples()
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for _, prevEventID := range backwardsExtremity.PrevEventIDs() {
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var prevState *gomatrixserverlib.RespState
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prevState, err = t.lookupStateAfterEvent(roomVersion, backwardsExtremity.RoomID(), prevEventID, needed)
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if err != nil {
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util.GetLogger(t.context).WithError(err).Errorf("Failed to lookup state after prev_event: %s", prevEventID)
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return err
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}
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states = append(states, prevState)
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}
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|
resolvedState, err := t.resolveStatesAndCheck(roomVersion, states, backwardsExtremity)
|
|
if err != nil {
|
|
util.GetLogger(t.context).WithError(err).Errorf("Failed to resolve state conflicts for event %s", backwardsExtremity.EventID())
|
|
return err
|
|
}
|
|
|
|
// pass the event along with the state to the roomserver using a background context so we don't
|
|
// needlessly expire
|
|
return api.SendEventWithState(context.Background(), t.rsAPI, resolvedState, e.Headered(roomVersion), t.haveEventIDs())
|
|
}
|
|
|
|
// lookupStateAfterEvent returns the room state after `eventID`, which is the state before eventID with the state of `eventID` (if it's a state event)
|
|
// added into the mix.
|
|
func (t *txnReq) lookupStateAfterEvent(roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string, needed []gomatrixserverlib.StateKeyTuple) (*gomatrixserverlib.RespState, error) {
|
|
// try doing all this locally before we resort to querying federation
|
|
respState := t.lookupStateAfterEventLocally(roomID, eventID, needed)
|
|
if respState != nil {
|
|
return respState, nil
|
|
}
|
|
|
|
respState, err := t.lookupStateBeforeEvent(roomVersion, roomID, eventID)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// fetch the event we're missing and add it to the pile
|
|
h, err := t.lookupEvent(roomVersion, eventID, false)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
t.haveEvents[h.EventID()] = h
|
|
if h.StateKey() != nil {
|
|
addedToState := false
|
|
for i := range respState.StateEvents {
|
|
se := respState.StateEvents[i]
|
|
if se.Type() == h.Type() && se.StateKeyEquals(*h.StateKey()) {
|
|
respState.StateEvents[i] = h.Unwrap()
|
|
addedToState = true
|
|
break
|
|
}
|
|
}
|
|
if !addedToState {
|
|
respState.StateEvents = append(respState.StateEvents, h.Unwrap())
|
|
}
|
|
}
|
|
|
|
return respState, nil
|
|
}
|
|
|
|
func (t *txnReq) lookupStateAfterEventLocally(roomID, eventID string, needed []gomatrixserverlib.StateKeyTuple) *gomatrixserverlib.RespState {
|
|
var res api.QueryStateAfterEventsResponse
|
|
err := t.rsAPI.QueryStateAfterEvents(t.context, &api.QueryStateAfterEventsRequest{
|
|
RoomID: roomID,
|
|
PrevEventIDs: []string{eventID},
|
|
StateToFetch: needed,
|
|
}, &res)
|
|
if err != nil || !res.PrevEventsExist {
|
|
util.GetLogger(t.context).WithError(err).Warnf("failed to query state after %s locally", eventID)
|
|
return nil
|
|
}
|
|
for i, ev := range res.StateEvents {
|
|
t.haveEvents[ev.EventID()] = &res.StateEvents[i]
|
|
}
|
|
var authEvents []gomatrixserverlib.Event
|
|
missingAuthEvents := make(map[string]bool)
|
|
for _, ev := range res.StateEvents {
|
|
for _, ae := range ev.AuthEventIDs() {
|
|
aev, ok := t.haveEvents[ae]
|
|
if ok {
|
|
authEvents = append(authEvents, aev.Unwrap())
|
|
} else {
|
|
missingAuthEvents[ae] = true
|
|
}
|
|
}
|
|
}
|
|
// QueryStateAfterEvents does not return the auth events, so fetch them now. We know the roomserver has them else it wouldn't
|
|
// have stored the event.
|
|
var missingEventList []string
|
|
for evID := range missingAuthEvents {
|
|
missingEventList = append(missingEventList, evID)
|
|
}
|
|
queryReq := api.QueryEventsByIDRequest{
|
|
EventIDs: missingEventList,
|
|
}
|
|
util.GetLogger(t.context).Infof("Fetching missing auth events: %v", missingEventList)
|
|
var queryRes api.QueryEventsByIDResponse
|
|
if err = t.rsAPI.QueryEventsByID(t.context, &queryReq, &queryRes); err != nil {
|
|
return nil
|
|
}
|
|
for i := range queryRes.Events {
|
|
evID := queryRes.Events[i].EventID()
|
|
t.haveEvents[evID] = &queryRes.Events[i]
|
|
authEvents = append(authEvents, queryRes.Events[i].Unwrap())
|
|
}
|
|
|
|
evs := gomatrixserverlib.UnwrapEventHeaders(res.StateEvents)
|
|
return &gomatrixserverlib.RespState{
|
|
StateEvents: evs,
|
|
AuthEvents: authEvents,
|
|
}
|
|
}
|
|
|
|
// lookuptStateBeforeEvent returns the room state before the event e, which is just /state_ids and/or /state depending on what
|
|
// the server supports.
|
|
func (t *txnReq) lookupStateBeforeEvent(roomVersion gomatrixserverlib.RoomVersion, roomID, eventID string) (
|
|
respState *gomatrixserverlib.RespState, err error) {
|
|
|
|
util.GetLogger(t.context).Infof("lookupStateBeforeEvent %s", eventID)
|
|
|
|
// Attempt to fetch the missing state using /state_ids and /events
|
|
respState, err = t.lookupMissingStateViaStateIDs(roomID, eventID, roomVersion)
|
|
if err != nil {
|
|
// Fallback to /state
|
|
util.GetLogger(t.context).WithError(err).Warn("lookupStateBeforeEvent failed to /state_ids, falling back to /state")
|
|
respState, err = t.lookupMissingStateViaState(roomID, eventID, roomVersion)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (t *txnReq) resolveStatesAndCheck(roomVersion gomatrixserverlib.RoomVersion, states []*gomatrixserverlib.RespState, backwardsExtremity *gomatrixserverlib.Event) (*gomatrixserverlib.RespState, error) {
|
|
var authEventList []gomatrixserverlib.Event
|
|
var stateEventList []gomatrixserverlib.Event
|
|
for _, state := range states {
|
|
authEventList = append(authEventList, state.AuthEvents...)
|
|
stateEventList = append(stateEventList, state.StateEvents...)
|
|
}
|
|
resolvedStateEvents, err := gomatrixserverlib.ResolveConflicts(roomVersion, stateEventList, authEventList)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// apply the current event
|
|
retryAllowedState:
|
|
if err = checkAllowedByState(*backwardsExtremity, resolvedStateEvents); err != nil {
|
|
switch missing := err.(type) {
|
|
case gomatrixserverlib.MissingAuthEventError:
|
|
h, err2 := t.lookupEvent(roomVersion, missing.AuthEventID, true)
|
|
if err2 != nil {
|
|
return nil, fmt.Errorf("missing auth event %s and failed to look it up: %w", missing.AuthEventID, err2)
|
|
}
|
|
util.GetLogger(t.context).Infof("fetched event %s", missing.AuthEventID)
|
|
resolvedStateEvents = append(resolvedStateEvents, h.Unwrap())
|
|
goto retryAllowedState
|
|
default:
|
|
}
|
|
return nil, err
|
|
}
|
|
return &gomatrixserverlib.RespState{
|
|
AuthEvents: authEventList,
|
|
StateEvents: resolvedStateEvents,
|
|
}, nil
|
|
}
|
|
|
|
// getMissingEvents returns a nil backwardsExtremity if missing events were fetched and handled, else returns the new backwards extremity which we should
|
|
// begin from. Returns an error only if we should terminate the transaction which initiated /get_missing_events
|
|
// This function recursively calls txnReq.processEvent with the missing events, which will be processed before this function returns.
|
|
// This means that we may recursively call this function, as we spider back up prev_events to the min depth.
|
|
func (t *txnReq) getMissingEvents(e gomatrixserverlib.Event, roomVersion gomatrixserverlib.RoomVersion, isInboundTxn bool) (backwardsExtremity *gomatrixserverlib.Event, err error) {
|
|
if !isInboundTxn {
|
|
// we've recursed here, so just take a state snapshot please!
|
|
return &e, nil
|
|
}
|
|
logger := util.GetLogger(t.context).WithField("event_id", e.EventID()).WithField("room_id", e.RoomID())
|
|
needed := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{e})
|
|
// query latest events (our trusted forward extremities)
|
|
req := api.QueryLatestEventsAndStateRequest{
|
|
RoomID: e.RoomID(),
|
|
StateToFetch: needed.Tuples(),
|
|
}
|
|
var res api.QueryLatestEventsAndStateResponse
|
|
if err = t.rsAPI.QueryLatestEventsAndState(t.context, &req, &res); err != nil {
|
|
logger.WithError(err).Warn("Failed to query latest events")
|
|
return &e, nil
|
|
}
|
|
latestEvents := make([]string, len(res.LatestEvents))
|
|
for i := range res.LatestEvents {
|
|
latestEvents[i] = res.LatestEvents[i].EventID
|
|
}
|
|
// this server just sent us an event for which we do not know its prev_events - ask that server for those prev_events.
|
|
minDepth := int(res.Depth) - 20
|
|
if minDepth < 0 {
|
|
minDepth = 0
|
|
}
|
|
missingResp, err := t.federation.LookupMissingEvents(t.context, t.Origin, e.RoomID(), gomatrixserverlib.MissingEvents{
|
|
Limit: 20,
|
|
// synapse uses the min depth they've ever seen in that room
|
|
MinDepth: minDepth,
|
|
// The latest event IDs that the sender already has. These are skipped when retrieving the previous events of latest_events.
|
|
EarliestEvents: latestEvents,
|
|
// The event IDs to retrieve the previous events for.
|
|
LatestEvents: []string{e.EventID()},
|
|
}, roomVersion)
|
|
|
|
// security: how we handle failures depends on whether or not this event will become the new forward extremity for the room.
|
|
// There's 2 scenarios to consider:
|
|
// - Case A: We got pushed an event and are now fetching missing prev_events. (isInboundTxn=true)
|
|
// - Case B: We are fetching missing prev_events already and now fetching some more (isInboundTxn=false)
|
|
// In Case B, we know for sure that the event we are currently processing will not become the new forward extremity for the room,
|
|
// as it was called in response to an inbound txn which had it as a prev_event.
|
|
// In Case A, the event is a forward extremity, and could eventually become the _only_ forward extremity in the room. This is bad
|
|
// because it means we would trust the state at that event to be the state for the entire room, and allows rooms to be hijacked.
|
|
// https://github.com/matrix-org/synapse/pull/3456
|
|
// https://github.com/matrix-org/synapse/blob/229eb81498b0fe1da81e9b5b333a0285acde9446/synapse/handlers/federation.py#L335
|
|
// For now, we do not allow Case B, so reject the event.
|
|
if err != nil {
|
|
logger.WithError(err).Errorf(
|
|
"%s pushed us an event but couldn't give us details about prev_events via /get_missing_events - dropping this event until it can",
|
|
t.Origin,
|
|
)
|
|
return nil, missingPrevEventsError{
|
|
eventID: e.EventID(),
|
|
err: err,
|
|
}
|
|
}
|
|
logger.Infof("get_missing_events returned %d events", len(missingResp.Events))
|
|
|
|
// topologically sort and sanity check that we are making forward progress
|
|
newEvents := gomatrixserverlib.ReverseTopologicalOrdering(missingResp.Events, gomatrixserverlib.TopologicalOrderByPrevEvents)
|
|
shouldHaveSomeEventIDs := e.PrevEventIDs()
|
|
hasPrevEvent := false
|
|
Event:
|
|
for _, pe := range shouldHaveSomeEventIDs {
|
|
for _, ev := range newEvents {
|
|
if ev.EventID() == pe {
|
|
hasPrevEvent = true
|
|
break Event
|
|
}
|
|
}
|
|
}
|
|
if !hasPrevEvent {
|
|
err = fmt.Errorf("called /get_missing_events but server %s didn't return any prev_events with IDs %v", t.Origin, shouldHaveSomeEventIDs)
|
|
logger.WithError(err).Errorf(
|
|
"%s pushed us an event but couldn't give us details about prev_events via /get_missing_events - dropping this event until it can",
|
|
t.Origin,
|
|
)
|
|
return nil, missingPrevEventsError{
|
|
eventID: e.EventID(),
|
|
err: err,
|
|
}
|
|
}
|
|
// process the missing events then the event which started this whole thing
|
|
for _, ev := range append(newEvents, e) {
|
|
err := t.processEvent(ev, false)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
// we processed everything!
|
|
return nil, nil
|
|
}
|
|
|
|
func (t *txnReq) lookupMissingStateViaState(roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
|
|
respState *gomatrixserverlib.RespState, err error) {
|
|
state, err := t.federation.LookupState(t.context, t.Origin, roomID, eventID, roomVersion)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// Check that the returned state is valid.
|
|
if err := state.Check(t.context, t.keys, nil); err != nil {
|
|
return nil, err
|
|
}
|
|
return &state, nil
|
|
}
|
|
|
|
func (t *txnReq) lookupMissingStateViaStateIDs(roomID, eventID string, roomVersion gomatrixserverlib.RoomVersion) (
|
|
*gomatrixserverlib.RespState, error) {
|
|
util.GetLogger(t.context).Infof("lookupMissingStateViaStateIDs %s", eventID)
|
|
// fetch the state event IDs at the time of the event
|
|
stateIDs, err := t.federation.LookupStateIDs(t.context, t.Origin, roomID, eventID)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// work out which auth/state IDs are missing
|
|
wantIDs := append(stateIDs.StateEventIDs, stateIDs.AuthEventIDs...)
|
|
missing := make(map[string]bool)
|
|
var missingEventList []string
|
|
for _, sid := range wantIDs {
|
|
if _, ok := t.haveEvents[sid]; !ok {
|
|
if !missing[sid] {
|
|
missing[sid] = true
|
|
missingEventList = append(missingEventList, sid)
|
|
}
|
|
}
|
|
}
|
|
|
|
// fetch as many as we can from the roomserver
|
|
queryReq := api.QueryEventsByIDRequest{
|
|
EventIDs: missingEventList,
|
|
}
|
|
var queryRes api.QueryEventsByIDResponse
|
|
if err = t.rsAPI.QueryEventsByID(t.context, &queryReq, &queryRes); err != nil {
|
|
return nil, err
|
|
}
|
|
for i := range queryRes.Events {
|
|
evID := queryRes.Events[i].EventID()
|
|
t.haveEvents[evID] = &queryRes.Events[i]
|
|
if missing[evID] {
|
|
delete(missing, evID)
|
|
}
|
|
}
|
|
|
|
util.GetLogger(t.context).WithFields(logrus.Fields{
|
|
"missing": len(missing),
|
|
"event_id": eventID,
|
|
"room_id": roomID,
|
|
"total_state": len(stateIDs.StateEventIDs),
|
|
"total_auth_events": len(stateIDs.AuthEventIDs),
|
|
}).Info("Fetching missing state at event")
|
|
|
|
for missingEventID := range missing {
|
|
var h *gomatrixserverlib.HeaderedEvent
|
|
h, err = t.lookupEvent(roomVersion, missingEventID, false)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
t.haveEvents[h.EventID()] = h
|
|
}
|
|
resp, err := t.createRespStateFromStateIDs(stateIDs)
|
|
return resp, err
|
|
}
|
|
|
|
func (t *txnReq) createRespStateFromStateIDs(stateIDs gomatrixserverlib.RespStateIDs) (
|
|
*gomatrixserverlib.RespState, error) {
|
|
// create a RespState response using the response to /state_ids as a guide
|
|
respState := gomatrixserverlib.RespState{
|
|
AuthEvents: make([]gomatrixserverlib.Event, len(stateIDs.AuthEventIDs)),
|
|
StateEvents: make([]gomatrixserverlib.Event, len(stateIDs.StateEventIDs)),
|
|
}
|
|
|
|
for i := range stateIDs.StateEventIDs {
|
|
ev, ok := t.haveEvents[stateIDs.StateEventIDs[i]]
|
|
if !ok {
|
|
return nil, fmt.Errorf("missing state event %s", stateIDs.StateEventIDs[i])
|
|
}
|
|
respState.StateEvents[i] = ev.Unwrap()
|
|
}
|
|
for i := range stateIDs.AuthEventIDs {
|
|
ev, ok := t.haveEvents[stateIDs.AuthEventIDs[i]]
|
|
if !ok {
|
|
return nil, fmt.Errorf("missing auth event %s", stateIDs.AuthEventIDs[i])
|
|
}
|
|
respState.AuthEvents[i] = ev.Unwrap()
|
|
}
|
|
// We purposefully do not do auth checks on the returned events, as they will still
|
|
// be processed in the exact same way, just as a 'rejected' event
|
|
// TODO: Add a field to HeaderedEvent to indicate if the event is rejected.
|
|
return &respState, nil
|
|
}
|
|
|
|
func (t *txnReq) lookupEvent(roomVersion gomatrixserverlib.RoomVersion, missingEventID string, localFirst bool) (*gomatrixserverlib.HeaderedEvent, error) {
|
|
if localFirst {
|
|
// fetch from the roomserver
|
|
queryReq := api.QueryEventsByIDRequest{
|
|
EventIDs: []string{missingEventID},
|
|
}
|
|
var queryRes api.QueryEventsByIDResponse
|
|
if err := t.rsAPI.QueryEventsByID(t.context, &queryReq, &queryRes); err != nil {
|
|
util.GetLogger(t.context).Warnf("Failed to query roomserver for missing event %s: %s - falling back to remote", missingEventID, err)
|
|
} else if len(queryRes.Events) == 1 {
|
|
return &queryRes.Events[0], nil
|
|
}
|
|
}
|
|
txn, err := t.federation.GetEvent(t.context, t.Origin, missingEventID)
|
|
if err != nil || len(txn.PDUs) == 0 {
|
|
util.GetLogger(t.context).WithError(err).WithField("event_id", missingEventID).Warn("failed to get missing /event for event ID")
|
|
return nil, err
|
|
}
|
|
pdu := txn.PDUs[0]
|
|
var event gomatrixserverlib.Event
|
|
event, err = gomatrixserverlib.NewEventFromUntrustedJSON(pdu, roomVersion)
|
|
if err != nil {
|
|
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %q", event.EventID())
|
|
return nil, unmarshalError{err}
|
|
}
|
|
if err = gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
|
|
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
|
|
return nil, verifySigError{event.EventID(), err}
|
|
}
|
|
h := event.Headered(roomVersion)
|
|
t.newEvents[h.EventID()] = true
|
|
return &h, nil
|
|
}
|