dendrite/roomserver/internal/helpers/auth.go

310 lines
9.7 KiB
Go

// Copyright 2017 Vector Creations 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 helpers
import (
"context"
"fmt"
"sort"
"github.com/matrix-org/dendrite/roomserver/state"
"github.com/matrix-org/dendrite/roomserver/storage"
"github.com/matrix-org/dendrite/roomserver/types"
"github.com/matrix-org/gomatrixserverlib"
)
// CheckForSoftFail returns true if the event should be soft-failed
// and false otherwise. The return error value should be checked before
// the soft-fail bool.
func CheckForSoftFail(
ctx context.Context,
db storage.Database,
event gomatrixserverlib.HeaderedEvent,
stateEventIDs []string,
) (bool, error) {
rewritesState := len(stateEventIDs) > 1
var authStateEntries []types.StateEntry
var err error
if rewritesState {
authStateEntries, err = db.StateEntriesForEventIDs(ctx, stateEventIDs)
if err != nil {
return true, fmt.Errorf("StateEntriesForEventIDs failed: %w", err)
}
} else {
// Work out if the room exists.
var roomInfo *types.RoomInfo
roomInfo, err = db.RoomInfo(ctx, event.RoomID())
if err != nil {
return false, fmt.Errorf("db.RoomNID: %w", err)
}
if roomInfo == nil || roomInfo.IsStub {
return false, nil
}
// Then get the state entries for the current state snapshot.
// We'll use this to check if the event is allowed right now.
roomState := state.NewStateResolution(db, *roomInfo)
authStateEntries, err = roomState.LoadStateAtSnapshot(ctx, roomInfo.StateSnapshotNID)
if err != nil {
return true, fmt.Errorf("roomState.LoadStateAtSnapshot: %w", err)
}
}
// As a special case, it's possible that the room will have no
// state because we haven't received a m.room.create event yet.
// If we're now processing the first create event then never
// soft-fail it.
if len(authStateEntries) == 0 && event.Type() == gomatrixserverlib.MRoomCreate {
return false, nil
}
// Work out which of the state events we actually need.
stateNeeded := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{event.Unwrap()})
// Load the actual auth events from the database.
authEvents, err := loadAuthEvents(ctx, db, stateNeeded, authStateEntries)
if err != nil {
return true, fmt.Errorf("loadAuthEvents: %w", err)
}
// Check if the event is allowed.
if err = gomatrixserverlib.Allowed(event.Event, &authEvents); err != nil {
// return true, nil
return true, err
}
return false, nil
}
// CheckAuthEvents checks that the event passes authentication checks
// Returns the numeric IDs for the auth events.
func CheckAuthEvents(
ctx context.Context,
db storage.Database,
event gomatrixserverlib.HeaderedEvent,
authEventIDs []string,
) ([]types.EventNID, error) {
// Grab the numeric IDs for the supplied auth state events from the database.
authStateEntries, err := db.StateEntriesForEventIDs(ctx, authEventIDs)
if err != nil {
return nil, fmt.Errorf("db.StateEntriesForEventIDs: %w", err)
}
authStateEntries = types.DeduplicateStateEntries(authStateEntries)
// Work out which of the state events we actually need.
stateNeeded := gomatrixserverlib.StateNeededForAuth([]gomatrixserverlib.Event{event.Unwrap()})
// Load the actual auth events from the database.
authEvents, err := loadAuthEvents(ctx, db, stateNeeded, authStateEntries)
if err != nil {
return nil, fmt.Errorf("loadAuthEvents: %w", err)
}
// Check if the event is allowed.
if err = gomatrixserverlib.Allowed(event.Event, &authEvents); err != nil {
return nil, err
}
// Return the numeric IDs for the auth events.
result := make([]types.EventNID, len(authStateEntries))
for i := range authStateEntries {
result[i] = authStateEntries[i].EventNID
}
return result, nil
}
type authEvents struct {
stateKeyNIDMap map[string]types.EventStateKeyNID
state stateEntryMap
events EventMap
}
// Create implements gomatrixserverlib.AuthEventProvider
func (ae *authEvents) Create() (*gomatrixserverlib.Event, error) {
return ae.lookupEventWithEmptyStateKey(types.MRoomCreateNID), nil
}
// PowerLevels implements gomatrixserverlib.AuthEventProvider
func (ae *authEvents) PowerLevels() (*gomatrixserverlib.Event, error) {
return ae.lookupEventWithEmptyStateKey(types.MRoomPowerLevelsNID), nil
}
// JoinRules implements gomatrixserverlib.AuthEventProvider
func (ae *authEvents) JoinRules() (*gomatrixserverlib.Event, error) {
return ae.lookupEventWithEmptyStateKey(types.MRoomJoinRulesNID), nil
}
// Memmber implements gomatrixserverlib.AuthEventProvider
func (ae *authEvents) Member(stateKey string) (*gomatrixserverlib.Event, error) {
return ae.lookupEvent(types.MRoomMemberNID, stateKey), nil
}
// ThirdPartyInvite implements gomatrixserverlib.AuthEventProvider
func (ae *authEvents) ThirdPartyInvite(stateKey string) (*gomatrixserverlib.Event, error) {
return ae.lookupEvent(types.MRoomThirdPartyInviteNID, stateKey), nil
}
func (ae *authEvents) lookupEventWithEmptyStateKey(typeNID types.EventTypeNID) *gomatrixserverlib.Event {
eventNID, ok := ae.state.lookup(types.StateKeyTuple{
EventTypeNID: typeNID,
EventStateKeyNID: types.EmptyStateKeyNID,
})
if !ok {
return nil
}
event, ok := ae.events.Lookup(eventNID)
if !ok {
return nil
}
return &event.Event
}
func (ae *authEvents) lookupEvent(typeNID types.EventTypeNID, stateKey string) *gomatrixserverlib.Event {
stateKeyNID, ok := ae.stateKeyNIDMap[stateKey]
if !ok {
return nil
}
eventNID, ok := ae.state.lookup(types.StateKeyTuple{
EventTypeNID: typeNID,
EventStateKeyNID: stateKeyNID,
})
if !ok {
return nil
}
event, ok := ae.events.Lookup(eventNID)
if !ok {
return nil
}
return &event.Event
}
// loadAuthEvents loads the events needed for authentication from the supplied room state.
func loadAuthEvents(
ctx context.Context,
db storage.Database,
needed gomatrixserverlib.StateNeeded,
state []types.StateEntry,
) (result authEvents, err error) {
// Look up the numeric IDs for the state keys needed for auth.
var neededStateKeys []string
neededStateKeys = append(neededStateKeys, needed.Member...)
neededStateKeys = append(neededStateKeys, needed.ThirdPartyInvite...)
if result.stateKeyNIDMap, err = db.EventStateKeyNIDs(ctx, neededStateKeys); err != nil {
return
}
// Load the events we need.
result.state = state
var eventNIDs []types.EventNID
keyTuplesNeeded := stateKeyTuplesNeeded(result.stateKeyNIDMap, needed)
for _, keyTuple := range keyTuplesNeeded {
eventNID, ok := result.state.lookup(keyTuple)
if ok {
eventNIDs = append(eventNIDs, eventNID)
}
}
if result.events, err = db.Events(ctx, eventNIDs); err != nil {
return
}
return
}
// stateKeyTuplesNeeded works out which numeric state key tuples we need to authenticate some events.
func stateKeyTuplesNeeded(
stateKeyNIDMap map[string]types.EventStateKeyNID,
stateNeeded gomatrixserverlib.StateNeeded,
) []types.StateKeyTuple {
var keyTuples []types.StateKeyTuple
if stateNeeded.Create {
keyTuples = append(keyTuples, types.StateKeyTuple{
EventTypeNID: types.MRoomCreateNID,
EventStateKeyNID: types.EmptyStateKeyNID,
})
}
if stateNeeded.PowerLevels {
keyTuples = append(keyTuples, types.StateKeyTuple{
EventTypeNID: types.MRoomPowerLevelsNID,
EventStateKeyNID: types.EmptyStateKeyNID,
})
}
if stateNeeded.JoinRules {
keyTuples = append(keyTuples, types.StateKeyTuple{
EventTypeNID: types.MRoomJoinRulesNID,
EventStateKeyNID: types.EmptyStateKeyNID,
})
}
for _, member := range stateNeeded.Member {
stateKeyNID, ok := stateKeyNIDMap[member]
if ok {
keyTuples = append(keyTuples, types.StateKeyTuple{
EventTypeNID: types.MRoomMemberNID,
EventStateKeyNID: stateKeyNID,
})
}
}
for _, token := range stateNeeded.ThirdPartyInvite {
stateKeyNID, ok := stateKeyNIDMap[token]
if ok {
keyTuples = append(keyTuples, types.StateKeyTuple{
EventTypeNID: types.MRoomThirdPartyInviteNID,
EventStateKeyNID: stateKeyNID,
})
}
}
return keyTuples
}
// Map from event type, state key tuple to numeric event ID.
// Implemented using binary search on a sorted array.
type stateEntryMap []types.StateEntry
// lookup an entry in the event map.
func (m stateEntryMap) lookup(stateKey types.StateKeyTuple) (eventNID types.EventNID, ok bool) {
// Since the list is sorted we can implement this using binary search.
// This is faster than using a hash map.
// We don't have to worry about pathological cases because the keys are fixed
// size and are controlled by us.
list := []types.StateEntry(m)
i := sort.Search(len(list), func(i int) bool {
return !list[i].StateKeyTuple.LessThan(stateKey)
})
if i < len(list) && list[i].StateKeyTuple == stateKey {
ok = true
eventNID = list[i].EventNID
}
return
}
// Map from numeric event ID to event.
// Implemented using binary search on a sorted array.
type EventMap []types.Event
// lookup an entry in the event map.
func (m EventMap) Lookup(eventNID types.EventNID) (event *types.Event, ok bool) {
// Since the list is sorted we can implement this using binary search.
// This is faster than using a hash map.
// We don't have to worry about pathological cases because the keys are fixed
// size are controlled by us.
list := []types.Event(m)
i := sort.Search(len(list), func(i int) bool {
return list[i].EventNID >= eventNID
})
if i < len(list) && list[i].EventNID == eventNID {
ok = true
event = &list[i]
}
return
}