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package clients
import (
"errors"
"regexp"
"sync"
"sync/atomic"
"time"
"github.com/matrix-org/go-neb/api"
"github.com/matrix-org/go-neb/database"
"github.com/matrix-org/go-neb/matrix"
log "github.com/sirupsen/logrus"
"golang.org/x/net/context"
"maunium.net/go/mautrix"
"maunium.net/go/mautrix/crypto"
"maunium.net/go/mautrix/event"
mevt "maunium.net/go/mautrix/event"
"maunium.net/go/mautrix/id"
)
// maximumVerifications is the number of maximum ongoing SAS verifications at a time.
// After this limit we start ignoring verification requests.
const maximumVerifications = 100
// BotClient represents one of the bot's sessions, with a specific User and Device ID.
// It can be used for sending messages and retrieving information about the rooms that
// the client has joined.
type BotClient struct {
*mautrix.Client
config api.ClientConfig
olmMachine *crypto.OlmMachine
stateStore *NebStateStore
verificationSAS *sync.Map
ongoingVerificationCount int32
}
// InitOlmMachine initializes a BotClient's internal OlmMachine given a client object and a Neb store,
// which will be used to store room information.
func (botClient *BotClient) InitOlmMachine(client *mautrix.Client, nebStore *matrix.NEBStore) (err error) {
var cryptoStore crypto.Store
cryptoLogger := CryptoMachineLogger{}
if sdb, ok := database.GetServiceDB().(*database.ServiceDB); ok {
// Create an SQL crypto store based on the ServiceDB used
db, dialect := sdb.GetSQLDb()
accountID := botClient.config.UserID.String() + "-" + client.DeviceID.String()
sqlCryptoStore := crypto.NewSQLCryptoStore(db, dialect, accountID, client.DeviceID, []byte(client.DeviceID.String()+"pickle"), cryptoLogger)
// Try to create the tables if they are missing
if err = sqlCryptoStore.CreateTables(); err != nil {
return
}
cryptoStore = sqlCryptoStore
cryptoLogger.Debug("Using SQL backend as the crypto store")
} else {
deviceID := client.DeviceID.String()
if deviceID == "" {
deviceID = "_empty_device_id"
}
cryptoStore, err = crypto.NewGobStore(deviceID + ".gob")
if err != nil {
return
}
cryptoLogger.Debug("Using gob storage as the crypto store")
}
botClient.stateStore = &NebStateStore{&nebStore.InMemoryStore}
olmMachine := crypto.NewOlmMachine(client, cryptoLogger, cryptoStore, botClient.stateStore)
regexes := make([]*regexp.Regexp, 0, len(botClient.config.AcceptVerificationFromUsers))
for _, userRegex := range botClient.config.AcceptVerificationFromUsers {
regex, err := regexp.Compile(userRegex)
if err != nil {
cryptoLogger.Error("Error compiling regex %v: %v", userRegex, err)
} else {
regexes = append(regexes, regex)
}
}
olmMachine.AcceptVerificationFrom = func(_ string, otherDevice *crypto.DeviceIdentity) (crypto.VerificationRequestResponse, crypto.VerificationHooks) {
for _, regex := range regexes {
if regex.MatchString(otherDevice.UserID.String()) {
if atomic.LoadInt32(&botClient.ongoingVerificationCount) >= maximumVerifications {
cryptoLogger.Trace("User ID %v matches regex %v but we are currently at maximum verifications, ignoring...", otherDevice.UserID, regex)
return crypto.IgnoreRequest, botClient
}
cryptoLogger.Trace("User ID %v matches regex %v, accepting SAS request", otherDevice.UserID, regex)
atomic.AddInt32(&botClient.ongoingVerificationCount, 1)
return crypto.AcceptRequest, botClient
}
}
cryptoLogger.Trace("User ID %v does not match any regex, rejecting SAS request", otherDevice.UserID)
return crypto.RejectRequest, botClient
}
if err = olmMachine.Load(); err != nil {
return
}
botClient.olmMachine = olmMachine
return nil
}
// Register registers a BotClient's Sync and StateMember event callbacks to update its internal state
// when new events arrive.
func (botClient *BotClient) Register(syncer mautrix.ExtensibleSyncer) {
syncer.OnEventType(mevt.StateMember, func(_ mautrix.EventSource, evt *mevt.Event) {
botClient.olmMachine.HandleMemberEvent(evt)
})
syncer.OnSync(botClient.syncCallback)
}
func (botClient *BotClient) syncCallback(resp *mautrix.RespSync, since string) bool {
botClient.stateStore.UpdateStateStore(resp)
botClient.olmMachine.ProcessSyncResponse(resp, since)
if err := botClient.olmMachine.CryptoStore.Flush(); err != nil {
log.WithError(err).Error("Could not flush crypto store")
}
return true
}
// DecryptMegolmEvent attempts to decrypt an incoming m.room.encrypted message using the session information
// already present in the OlmMachine. The corresponding decrypted event is then returned.
// If it fails, usually because the session is not known, an error is returned.
func (botClient *BotClient) DecryptMegolmEvent(evt *mevt.Event) (*mevt.Event, error) {
return botClient.olmMachine.DecryptMegolmEvent(evt)
}
// SendMessageEvent sends the given content to the given room ID using this BotClient as a message event.
// If the target room has enabled encryption, a megolm session is created if one doesn't already exist
// and the message is sent after being encrypted.
func (botClient *BotClient) SendMessageEvent(roomID id.RoomID, evtType mevt.Type, content interface{},
extra ...mautrix.ReqSendEvent) (*mautrix.RespSendEvent, error) {
olmMachine := botClient.olmMachine
if olmMachine.StateStore.IsEncrypted(roomID) {
// Check if there is already a megolm session
if sess, err := olmMachine.CryptoStore.GetOutboundGroupSession(roomID); err != nil {
return nil, err
} else if sess == nil || sess.Expired() || !sess.Shared {
// No error but valid, shared session does not exist
memberIDs, err := botClient.stateStore.GetJoinedMembers(roomID)
if err != nil {
return nil, err
}
// Share group session with room members
if err = olmMachine.ShareGroupSession(roomID, memberIDs); err != nil {
return nil, err
}
}
enc, err := olmMachine.EncryptMegolmEvent(roomID, mevt.EventMessage, content)
if err != nil {
return nil, err
}
content = enc
evtType = mevt.EventEncrypted
}
return botClient.Client.SendMessageEvent(roomID, evtType, content, extra...)
}
// Sync loops to keep syncing the client with the homeserver by calling the /sync endpoint.
func (botClient *BotClient) Sync() {
// Get the state store up to date
resp, err := botClient.SyncRequest(30000, "", "", true, mevt.PresenceOnline)
if err != nil {
log.WithError(err).Error("Error performing initial sync")
return
}
botClient.stateStore.UpdateStateStore(resp)
for {
if e := botClient.Client.Sync(); e != nil {
log.WithFields(log.Fields{
log.ErrorKey: e,
"user_id": botClient.config.UserID,
}).Error("Fatal Sync() error")
time.Sleep(10 * time.Second)
} else {
log.WithField("user_id", botClient.config.UserID).Info("Stopping Sync()")
return
}
}
}
// VerifySASMatch returns whether the received SAS matches the SAS that the bot generated.
// It retrieves the SAS of the other device from the bot client's SAS sync map, where it was stored by the `SubmitDecimalSAS` function.
func (botClient *BotClient) VerifySASMatch(otherDevice *crypto.DeviceIdentity, sas crypto.SASData) bool {
log.WithFields(log.Fields{
"otherUser": otherDevice.UserID,
"otherDevice": otherDevice.DeviceID,
}).Infof("Waiting for SAS")
if sas.Type() != event.SASDecimal {
log.Warnf("Unsupported SAS type: %v", sas.Type())
return false
}
key := otherDevice.UserID.String() + ":" + otherDevice.DeviceID.String()
sasChan, loaded := botClient.verificationSAS.LoadOrStore(key, make(chan crypto.DecimalSASData))
if !loaded {
// if we created the chan, delete it after the timeout duration
defer botClient.verificationSAS.Delete(key)
}
select {
case otherSAS := <-sasChan.(chan crypto.DecimalSASData):
ourSAS := sas.(crypto.DecimalSASData)
log.WithFields(log.Fields{
"otherUser": otherDevice.UserID,
"otherDevice": otherDevice.DeviceID,
}).Warnf("Our SAS: %v, Received SAS: %v, Match: %v", ourSAS, otherSAS, ourSAS == otherSAS)
return ourSAS == otherSAS
case <-time.After(botClient.olmMachine.DefaultSASTimeout):
log.Warnf("Timed out while waiting for SAS from device %v", otherDevice.DeviceID)
}
return false
}
// SubmitDecimalSAS stores the received decimal SAS from another device to compare to the local one.
// It stores the SAS in the bot client's SAS sync map to be retrieved from the `VerifySASMatch` function.
func (botClient *BotClient) SubmitDecimalSAS(otherUser id.UserID, otherDevice id.DeviceID, sas crypto.DecimalSASData) {
key := otherUser.String() + ":" + otherDevice.String()
sasChan, loaded := botClient.verificationSAS.LoadOrStore(key, make(chan crypto.DecimalSASData))
go func() {
if !loaded {
// if we created the chan, delete it after the timeout duration
defer botClient.verificationSAS.Delete(key)
}
// insert to channel in goroutine to avoid blocking if we are not expecting a SAS for this user/device right now
select {
case sasChan.(chan crypto.DecimalSASData) <- crypto.DecimalSASData(sas):
case <-time.After(botClient.olmMachine.DefaultSASTimeout):
log.Warnf("Timed out while trying to send SAS for device %v", otherDevice)
}
}()
}
// VerificationMethods returns the supported SAS verification methods.
// As a bot we only support decimal as it's easier to understand.
func (botClient *BotClient) VerificationMethods() []crypto.VerificationMethod {
return []crypto.VerificationMethod{
crypto.VerificationMethodDecimal{},
}
}
// OnCancel is called when a SAS verification is canceled.
func (botClient *BotClient) OnCancel(cancelledByUs bool, reason string, reasonCode event.VerificationCancelCode) {
atomic.AddInt32(&botClient.ongoingVerificationCount, -1)
log.Tracef("Verification cancelled with reason: %v", reason)
}
// OnSuccess is called when a SAS verification is successful.
func (botClient *BotClient) OnSuccess() {
atomic.AddInt32(&botClient.ongoingVerificationCount, -1)
log.Trace("Verification was successful")
}
// InvalidateRoomSession invalidates the outbound group session for the given room.
func (botClient *BotClient) InvalidateRoomSession(roomID id.RoomID) (id.SessionID, error) {
outbound, err := botClient.olmMachine.CryptoStore.GetOutboundGroupSession(roomID)
if err != nil {
return "", err
}
if outbound == nil {
return "", errors.New("No group session found for this room")
}
return outbound.ID(), botClient.olmMachine.CryptoStore.RemoveOutboundGroupSession(roomID)
}
// StartSASVerification starts a new SAS verification with the given user and device ID and returns the transaction ID if successful.
func (botClient *BotClient) StartSASVerification(userID id.UserID, deviceID id.DeviceID) (string, error) {
device, err := botClient.olmMachine.GetOrFetchDevice(userID, deviceID)
if err != nil {
return "", err
}
return botClient.olmMachine.NewSimpleSASVerificationWith(device, botClient)
}
// SendRoomKeyRequest sends a room key request to another device.
func (botClient *BotClient) SendRoomKeyRequest(userID id.UserID, deviceID id.DeviceID, roomID id.RoomID,
senderKey id.SenderKey, sessionID id.SessionID, timeout time.Duration) (chan bool, error) {
ctx, _ := context.WithTimeout(context.Background(), timeout)
return botClient.olmMachine.RequestRoomKey(ctx, userID, deviceID, roomID, senderKey, sessionID)
}
// ForwardRoomKeyToDevice sends a room key to another device.
func (botClient *BotClient) ForwardRoomKeyToDevice(userID id.UserID, deviceID id.DeviceID, roomID id.RoomID, senderKey id.SenderKey,
sessionID id.SessionID) error {
device, err := botClient.olmMachine.GetOrFetchDevice(userID, deviceID)
if err != nil {
return err
}
igs, err := botClient.olmMachine.CryptoStore.GetGroupSession(roomID, senderKey, sessionID)
if err != nil {
return err
} else if igs == nil {
return errors.New("Group session not found")
}
exportedKey, err := igs.Internal.Export(igs.Internal.FirstKnownIndex())
if err != nil {
return err
}
forwardedRoomKey := event.Content{
Parsed: &event.ForwardedRoomKeyEventContent{
RoomKeyEventContent: event.RoomKeyEventContent{
Algorithm: id.AlgorithmMegolmV1,
RoomID: igs.RoomID,
SessionID: igs.ID(),
SessionKey: exportedKey,
},
SenderKey: senderKey,
ForwardingKeyChain: igs.ForwardingChains,
SenderClaimedKey: igs.SigningKey,
},
}
return botClient.olmMachine.SendEncryptedToDevice(device, forwardedRoomKey)
}