protocol/pushnotificationserver/server.go
package pushnotificationserver
import (
"bytes"
"context"
"crypto/ecdsa"
"encoding/hex"
"github.com/golang/protobuf/proto"
"github.com/google/uuid"
"github.com/pkg/errors"
"go.uber.org/zap"
"github.com/status-im/status-go/eth-node/crypto"
"github.com/status-im/status-go/eth-node/crypto/ecies"
"github.com/status-im/status-go/eth-node/types"
"github.com/status-im/status-go/protocol/common"
"github.com/status-im/status-go/protocol/protobuf"
)
const encryptedPayloadKeyLength = 16
const defaultGorushURL = "https://gorush.status.im"
var errUnhandledPushNotificationType = errors.New("unhandled push notification type")
type Config struct {
Enabled bool
// Identity is our identity key
Identity *ecdsa.PrivateKey
// GorushUrl is the url for the gorush service
GorushURL string
Logger *zap.Logger
}
type Server struct {
persistence Persistence
config *Config
messageSender *common.MessageSender
// SentRequests keeps track of the requests sent to gorush, for testing only
SentRequests int64
}
func New(config *Config, persistence Persistence, messageSender *common.MessageSender) *Server {
if len(config.GorushURL) == 0 {
config.GorushURL = defaultGorushURL
}
return &Server{persistence: persistence, config: config, messageSender: messageSender}
}
func (s *Server) Start() error {
if s.config.Logger == nil {
logger, err := zap.NewDevelopment()
if err != nil {
return errors.Wrap(err, "failed to create a logger")
}
s.config.Logger = logger
}
s.config.Logger.Info("starting push notification server")
if s.config.Identity == nil {
s.config.Logger.Debug("Identity nil")
// Pull identity from database
identity, err := s.persistence.GetIdentity()
if err != nil {
return err
}
if identity == nil {
identity, err = crypto.GenerateKey()
if err != nil {
return err
}
if err := s.persistence.SaveIdentity(identity); err != nil {
return err
}
}
s.config.Identity = identity
}
pks, err := s.persistence.GetPushNotificationRegistrationPublicKeys()
if err != nil {
return err
}
// listen to all topics for users registered
for _, pk := range pks {
if err := s.listenToPublicKeyQueryTopic(pk); err != nil {
return err
}
}
s.config.Logger.Info("started push notification server", zap.String("identity", types.EncodeHex(crypto.FromECDSAPub(&s.config.Identity.PublicKey))))
return nil
}
// HandlePushNotificationRegistration builds a response for the registration and sends it back to the user
func (s *Server) HandlePushNotificationRegistration(publicKey *ecdsa.PublicKey, payload []byte) error {
response := s.buildPushNotificationRegistrationResponse(publicKey, payload)
if response == nil {
return nil
}
encodedMessage, err := proto.Marshal(response)
if err != nil {
return err
}
rawMessage := common.RawMessage{
Payload: encodedMessage,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_REGISTRATION_RESPONSE,
// we skip encryption as might be sent from an ephemeral key
SkipEncryptionLayer: true,
}
_, err = s.messageSender.SendPrivate(context.Background(), publicKey, &rawMessage)
return err
}
// HandlePushNotificationQuery builds a response for the query and sends it back to the user
func (s *Server) HandlePushNotificationQuery(publicKey *ecdsa.PublicKey, messageID []byte, query *protobuf.PushNotificationQuery) error {
if query == nil {
return nil
}
response := s.buildPushNotificationQueryResponse(query)
if response == nil {
return nil
}
response.MessageId = messageID
encodedMessage, err := proto.Marshal(response)
if err != nil {
return err
}
rawMessage := common.RawMessage{
Payload: encodedMessage,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_QUERY_RESPONSE,
// we skip encryption as sent from an ephemeral key
SkipEncryptionLayer: true,
}
_, err = s.messageSender.SendPrivate(context.Background(), publicKey, &rawMessage)
return err
}
// HandlePushNotificationRequest will send a gorush notification and send a response back to the user
func (s *Server) HandlePushNotificationRequest(publicKey *ecdsa.PublicKey,
messageID []byte,
request *protobuf.PushNotificationRequest) error {
s.config.Logger.Debug("handling pn request", zap.Binary("message-id", messageID))
// This is at-most-once semantic for now
exists, err := s.persistence.PushNotificationExists(messageID)
if err != nil {
return err
}
if exists {
s.config.Logger.Debug("already handled")
return nil
}
response, requestsAndRegistrations := s.buildPushNotificationRequestResponse(request)
//AndSendNotification(&request)
if response == nil {
return nil
}
err = s.sendPushNotification(requestsAndRegistrations)
if err != nil {
s.config.Logger.Error("failed to send go rush notification", zap.Error(err))
return err
}
encodedMessage, err := proto.Marshal(response)
if err != nil {
return err
}
rawMessage := common.RawMessage{
Payload: encodedMessage,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_RESPONSE,
// We skip encryption here as the message has been sent from an ephemeral key
SkipEncryptionLayer: true,
}
_, err = s.messageSender.SendPrivate(context.Background(), publicKey, &rawMessage)
return err
}
// buildGrantSignatureMaterial builds a grant for a specific server.
// We use 3 components:
// 1) The client public key. Not sure this applies to our signature scheme, but best to be conservative. https://crypto.stackexchange.com/questions/15538/given-a-message-and-signature-find-a-public-key-that-makes-the-signature-valid
// 2) The server public key
// 3) The access token
// By verifying this signature, a client can trust the server was instructed to store this access token.
func (s *Server) buildGrantSignatureMaterial(clientPublicKey *ecdsa.PublicKey, serverPublicKey *ecdsa.PublicKey, accessToken string) []byte {
var signatureMaterial []byte
signatureMaterial = append(signatureMaterial, crypto.CompressPubkey(clientPublicKey)...)
signatureMaterial = append(signatureMaterial, crypto.CompressPubkey(serverPublicKey)...)
signatureMaterial = append(signatureMaterial, []byte(accessToken)...)
a := crypto.Keccak256(signatureMaterial)
return a
}
func (s *Server) verifyGrantSignature(clientPublicKey *ecdsa.PublicKey, accessToken string, grant []byte) error {
signatureMaterial := s.buildGrantSignatureMaterial(clientPublicKey, &s.config.Identity.PublicKey, accessToken)
recoveredPublicKey, err := crypto.SigToPub(signatureMaterial, grant)
if err != nil {
return err
}
if !common.IsPubKeyEqual(recoveredPublicKey, clientPublicKey) {
return errors.New("pubkey mismatch")
}
return nil
}
func (s *Server) generateSharedKey(publicKey *ecdsa.PublicKey) ([]byte, error) {
return ecies.ImportECDSA(s.config.Identity).GenerateShared(
ecies.ImportECDSAPublic(publicKey),
encryptedPayloadKeyLength,
encryptedPayloadKeyLength,
)
}
func (s *Server) validateUUID(u string) error {
if len(u) == 0 {
return errors.New("empty uuid")
}
_, err := uuid.Parse(u)
return err
}
func (s *Server) decryptRegistration(publicKey *ecdsa.PublicKey, payload []byte) ([]byte, error) {
sharedKey, err := s.generateSharedKey(publicKey)
if err != nil {
return nil, err
}
return common.Decrypt(payload, sharedKey)
}
// validateRegistration validates a new message against the last one received for a given installationID and and public key
// and return the decrypted message
func (s *Server) validateRegistration(publicKey *ecdsa.PublicKey, payload []byte) (*protobuf.PushNotificationRegistration, error) {
if payload == nil {
return nil, ErrEmptyPushNotificationRegistrationPayload
}
if publicKey == nil {
return nil, ErrEmptyPushNotificationRegistrationPublicKey
}
decryptedPayload, err := s.decryptRegistration(publicKey, payload)
if err != nil {
return nil, err
}
registration := &protobuf.PushNotificationRegistration{}
if err := proto.Unmarshal(decryptedPayload, registration); err != nil {
return nil, ErrCouldNotUnmarshalPushNotificationRegistration
}
if registration.Version < 1 {
return nil, ErrInvalidPushNotificationRegistrationVersion
}
if err := s.validateUUID(registration.InstallationId); err != nil {
return nil, ErrMalformedPushNotificationRegistrationInstallationID
}
previousVersion, err := s.persistence.GetPushNotificationRegistrationVersion(common.HashPublicKey(publicKey), registration.InstallationId)
if err != nil {
return nil, err
}
if registration.Version <= previousVersion {
return nil, ErrInvalidPushNotificationRegistrationVersion
}
// unregistering message
if registration.Unregister {
return registration, nil
}
if err := s.validateUUID(registration.AccessToken); err != nil {
return nil, ErrMalformedPushNotificationRegistrationAccessToken
}
if len(registration.Grant) == 0 {
return nil, ErrMalformedPushNotificationRegistrationGrant
}
if err := s.verifyGrantSignature(publicKey, registration.AccessToken, registration.Grant); err != nil {
s.config.Logger.Error("failed to verify grant", zap.Error(err))
return nil, ErrMalformedPushNotificationRegistrationGrant
}
if len(registration.DeviceToken) == 0 {
return nil, ErrMalformedPushNotificationRegistrationDeviceToken
}
if registration.TokenType == protobuf.PushNotificationRegistration_UNKNOWN_TOKEN_TYPE {
return nil, ErrUnknownPushNotificationRegistrationTokenType
}
return registration, nil
}
// buildPushNotificationQueryResponse check if we have the client information and send them back
func (s *Server) buildPushNotificationQueryResponse(query *protobuf.PushNotificationQuery) *protobuf.PushNotificationQueryResponse {
s.config.Logger.Debug("handling push notification query")
response := &protobuf.PushNotificationQueryResponse{}
if query == nil || len(query.PublicKeys) == 0 {
return response
}
registrations, err := s.persistence.GetPushNotificationRegistrationByPublicKeys(query.PublicKeys)
if err != nil {
s.config.Logger.Error("failed to retrieve registration", zap.Error(err))
return response
}
for _, idAndResponse := range registrations {
registration := idAndResponse.Registration
info := &protobuf.PushNotificationQueryInfo{
PublicKey: idAndResponse.ID,
Grant: registration.Grant,
Version: registration.Version,
InstallationId: registration.InstallationId,
}
// if instructed to only allow from contacts, send back a list
if registration.AllowFromContactsOnly {
info.AllowedKeyList = registration.AllowedKeyList
} else {
info.AccessToken = registration.AccessToken
}
response.Info = append(response.Info, info)
}
response.Success = true
return response
}
func (s *Server) contains(list [][]byte, chatID []byte) bool {
for _, list := range list {
if bytes.Equal(list, chatID) {
return true
}
}
return false
}
type reportResult struct {
sendNotification bool
report *protobuf.PushNotificationReport
}
// buildPushNotificationReport checks the request against the registration and
// returns whether we should send the notification and what the response should be
func (s *Server) buildPushNotificationReport(pn *protobuf.PushNotification, registration *protobuf.PushNotificationRegistration) (*reportResult, error) {
response := &reportResult{}
report := &protobuf.PushNotificationReport{
PublicKey: pn.PublicKey,
InstallationId: pn.InstallationId,
}
if pn.Type == protobuf.PushNotification_UNKNOWN_PUSH_NOTIFICATION_TYPE {
s.config.Logger.Warn("unhandled type")
return nil, errUnhandledPushNotificationType
}
if registration == nil {
s.config.Logger.Warn("empty registration")
report.Error = protobuf.PushNotificationReport_NOT_REGISTERED
} else if registration.AccessToken != pn.AccessToken {
s.config.Logger.Debug("invalid token")
report.Error = protobuf.PushNotificationReport_WRONG_TOKEN
} else if (s.isMessageNotification(pn) && !s.isValidMessageNotification(pn, registration)) || (s.isMentionNotification(pn) && !s.isValidMentionNotification(pn, registration)) || (s.isRequestToJoinCommunityNotification(pn) && !s.isValidRequestToJoinCommunityNotification(pn, registration)) {
s.config.Logger.Debug("filtered notification")
// We report as successful but don't send the notification
// for privacy reasons, as otherwise we would disclose that
// the sending client has been blocked or that the registering
// client has not joined a given public chat
report.Success = true
} else {
response.sendNotification = true
s.config.Logger.Debug("sending push notification")
report.Success = true
}
response.report = report
return response, nil
}
// buildPushNotificationRequestResponse will build a response
func (s *Server) buildPushNotificationRequestResponse(request *protobuf.PushNotificationRequest) (*protobuf.PushNotificationResponse, []*RequestAndRegistration) {
response := &protobuf.PushNotificationResponse{}
// We don't even send a response in this case
if request == nil || len(request.MessageId) == 0 {
s.config.Logger.Warn("empty message id")
return nil, nil
}
response.MessageId = request.MessageId
// collect successful requests & registrations
var requestAndRegistrations []*RequestAndRegistration
for _, pn := range request.Requests {
registration, err := s.persistence.GetPushNotificationRegistrationByPublicKeyAndInstallationID(pn.PublicKey, pn.InstallationId)
var report *protobuf.PushNotificationReport
if err != nil {
report = &protobuf.PushNotificationReport{
PublicKey: pn.PublicKey,
Error: protobuf.PushNotificationReport_UNKNOWN_ERROR_TYPE,
InstallationId: pn.InstallationId,
}
} else {
response, err := s.buildPushNotificationReport(pn, registration)
if err != nil {
s.config.Logger.Warn("unhandled type")
continue
}
if response.sendNotification {
requestAndRegistrations = append(requestAndRegistrations, &RequestAndRegistration{
Request: pn,
Registration: registration,
})
}
report = response.report
}
response.Reports = append(response.Reports, report)
}
s.config.Logger.Debug("built pn request")
if len(requestAndRegistrations) == 0 {
s.config.Logger.Warn("no request and registration")
return response, nil
}
return response, requestAndRegistrations
}
func (s *Server) sendPushNotification(requestAndRegistrations []*RequestAndRegistration) error {
if len(requestAndRegistrations) == 0 {
return nil
}
s.SentRequests++
goRushRequest := PushNotificationRegistrationToGoRushRequest(requestAndRegistrations)
return sendGoRushNotification(goRushRequest, s.config.GorushURL, s.config.Logger)
}
// listenToPublicKeyQueryTopic listen to a topic derived from the hashed public key
func (s *Server) listenToPublicKeyQueryTopic(hashedPublicKey []byte) error {
if s.messageSender == nil {
return nil
}
encodedPublicKey := hex.EncodeToString(hashedPublicKey)
_, err := s.messageSender.JoinPublic(encodedPublicKey)
return err
}
// buildPushNotificationRegistrationResponse will check the registration is valid, save it, and listen to the topic for the queries
func (s *Server) buildPushNotificationRegistrationResponse(publicKey *ecdsa.PublicKey, payload []byte) *protobuf.PushNotificationRegistrationResponse {
s.config.Logger.Debug("handling push notification registration")
response := &protobuf.PushNotificationRegistrationResponse{
RequestId: common.Shake256(payload),
}
registration, err := s.validateRegistration(publicKey, payload)
if err != nil {
if err == ErrInvalidPushNotificationRegistrationVersion {
response.Error = protobuf.PushNotificationRegistrationResponse_VERSION_MISMATCH
} else {
response.Error = protobuf.PushNotificationRegistrationResponse_MALFORMED_MESSAGE
}
s.config.Logger.Warn("registration did not validate", zap.Error(err))
return response
}
if registration.Unregister {
s.config.Logger.Debug("unregistering client")
// We save an empty registration, only keeping version and installation-id
if err := s.persistence.UnregisterPushNotificationRegistration(common.HashPublicKey(publicKey), registration.InstallationId, registration.Version); err != nil {
response.Error = protobuf.PushNotificationRegistrationResponse_INTERNAL_ERROR
s.config.Logger.Error("failed to unregister ", zap.Error(err))
return response
}
} else if err := s.persistence.SavePushNotificationRegistration(common.HashPublicKey(publicKey), registration); err != nil {
response.Error = protobuf.PushNotificationRegistrationResponse_INTERNAL_ERROR
s.config.Logger.Error("failed to save registration", zap.Error(err))
return response
}
if err := s.listenToPublicKeyQueryTopic(common.HashPublicKey(publicKey)); err != nil {
response.Error = protobuf.PushNotificationRegistrationResponse_INTERNAL_ERROR
s.config.Logger.Error("failed to listen to topic", zap.Error(err))
return response
}
response.Success = true
s.config.Logger.Debug("handled push notification registration successfully")
return response
}
func (s *Server) isMentionNotification(pn *protobuf.PushNotification) bool {
return pn.Type == protobuf.PushNotification_MENTION
}
// isValidMentionNotification checks:
// this is a mention
// mentions are enabled
// the user joined the public chat
// the author is not blocked
func (s *Server) isValidMentionNotification(pn *protobuf.PushNotification, registration *protobuf.PushNotificationRegistration) bool {
return s.isMentionNotification(pn) && !registration.BlockMentions && s.contains(registration.AllowedMentionsChatList, pn.ChatId) && !s.contains(registration.BlockedChatList, pn.Author)
}
func (s *Server) isMessageNotification(pn *protobuf.PushNotification) bool {
return pn.Type == protobuf.PushNotification_MESSAGE
}
// isValidMessageNotification checks:
// this is a message
// the chat is not muted
// the author is not blocked
func (s *Server) isValidMessageNotification(pn *protobuf.PushNotification, registration *protobuf.PushNotificationRegistration) bool {
return s.isMessageNotification(pn) && !s.contains(registration.BlockedChatList, pn.ChatId) && !s.contains(registration.MutedChatList, pn.ChatId) && !s.contains(registration.BlockedChatList, pn.Author)
}
func (s *Server) isRequestToJoinCommunityNotification(pn *protobuf.PushNotification) bool {
return pn.Type == protobuf.PushNotification_REQUEST_TO_JOIN_COMMUNITY
}
// isValidRequestToJoinCommunityNotification checks:
// this is a request to join a community
// the author is not blocked
func (s *Server) isValidRequestToJoinCommunityNotification(pn *protobuf.PushNotification, registration *protobuf.PushNotificationRegistration) bool {
return s.isRequestToJoinCommunityNotification(pn) && !s.contains(registration.BlockedChatList, pn.Author)
}