protocol/pushnotificationclient/client.go
package pushnotificationclient
import (
"bytes"
"context"
"crypto/aes"
"crypto/cipher"
"crypto/ecdsa"
"crypto/rand"
"encoding/hex"
"encoding/json"
"errors"
"io"
"math"
mrand "math/rand"
"time"
"github.com/golang/protobuf/proto"
"github.com/google/uuid"
"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"
)
// How does sending notifications work?
// 1) Every time a message is scheduled for sending, it will be received on a channel.
// we keep track on whether we should send a push notification for this message.
// 2) Every time a message is dispatched, we check whether we should send a notification.
// If so, we query the user info if necessary, check which installations we should be targeting
// and notify the server if we have information about the user (i.e a token).
// The logic is complicated by the fact that sometimes messages are batched together (datasync)
// and the fact that sometimes we send messages to all devices (dh messages).
// 3) The server will notify us if the wrong token is used, in which case a loop will be started that
// will re-query and re-send the notification, up to a maximum.
// How does registering works?
// We register with the server asynchronously, through a loop, that will try to make sure that
// we have registered with all the servers added, until eventually it gives up.
// A lot of the logic is complicated by the fact that waku/whisper is not req/response, so we just fire a message
// hoping to get a reply at some later stages.
const encryptedPayloadKeyLength = 16
const accessTokenKeyLength = 16
const staleQueryTimeInSeconds = 86400
const mentionInstallationID = "mention"
const oneToOneChatIDLength = 132
// maxRegistrationRetries is the maximum number of attempts we do before giving up registering with a server
const maxRegistrationRetries int64 = 12
// maxPushNotificationRetries is the maximum number of attempts before we give up sending a push notification
const maxPushNotificationRetries int64 = 4
// pushNotificationBackoffTime is the step of the exponential backoff
const pushNotificationBackoffTime int64 = 2
// RegistrationBackoffTime is the step of the exponential backoff
const RegistrationBackoffTime int64 = 15
// defaultPushNotificationsServerCount is how many push notification servers we should register with if none is selected
const defaultPushNotificationsServersCount = 3
type ServerType int
const (
ServerTypeDefault = iota + 1
ServerTypeCustom
)
type PushNotificationServer struct {
PublicKey *ecdsa.PublicKey `json:"-"`
Registered bool `json:"registered,omitempty"`
RegisteredAt int64 `json:"registeredAt,omitempty"`
LastRetriedAt int64 `json:"lastRetriedAt,omitempty"`
RetryCount int64 `json:"retryCount,omitempty"`
AccessToken string `json:"accessToken,omitempty"`
Type ServerType `json:"type,omitempty"`
}
func (s *PushNotificationServer) MarshalJSON() ([]byte, error) {
type ServerAlias PushNotificationServer
item := struct {
*ServerAlias
PublicKeyString string `json:"publicKey"`
}{
ServerAlias: (*ServerAlias)(s),
PublicKeyString: types.EncodeHex(crypto.FromECDSAPub(s.PublicKey)),
}
return json.Marshal(item)
}
type PushNotificationInfo struct {
AccessToken string
InstallationID string
PublicKey *ecdsa.PublicKey
ServerPublicKey *ecdsa.PublicKey
RetrievedAt int64
Version uint64
}
type SentNotification struct {
PublicKey *ecdsa.PublicKey
InstallationID string
LastTriedAt int64
RetryCount int64
MessageID []byte
ChatID string
NotificationType protobuf.PushNotification_PushNotificationType
Success bool
Error protobuf.PushNotificationReport_ErrorType
}
type RegistrationOptions struct {
PublicChatIDs []string
MutedChatIDs []string
BlockedChatIDs []string
ContactIDs []*ecdsa.PublicKey
}
func (s *SentNotification) HashedPublicKey() []byte {
return common.HashPublicKey(s.PublicKey)
}
type Config struct {
// Identity is our identity key
Identity *ecdsa.PrivateKey
// SendEnabled indicates whether we should be sending push notifications
SendEnabled bool
// RemoteNotificationsEnabled is whether we should register with a remote server for push notifications
RemoteNotificationsEnabled bool
// AllowyFromContactsOnly indicates whether we should be receiving push notifications
// only from contacts
AllowFromContactsOnly bool
// BlockMentions indicates whether we should not receive notification for mentions
BlockMentions bool
// InstallationID is the installation-id for this device
InstallationID string
Logger *zap.Logger
// DefaultServers holds the push notification servers used by
// default if none is selected
DefaultServers []*ecdsa.PublicKey
}
type MessagePersistence interface {
MessageByID(string) (*common.Message, error)
}
type Client struct {
persistence *Persistence
messagePersistence MessagePersistence
config *Config
// lastPushNotificationRegistration is the latest known push notification version
lastPushNotificationRegistration *protobuf.PushNotificationRegistration
// lastContactIDs is the latest contact ids array
lastContactIDs []*ecdsa.PublicKey
// AccessToken is the access token that is currently being used
AccessToken string
// deviceToken is the device token for this device
deviceToken string
// TokenType is the type of token
tokenType protobuf.PushNotificationRegistration_TokenType
// APNTopic is the topic of the apn topic for push notification
apnTopic string
// randomReader only used for testing so we have deterministic encryption
reader io.Reader
//messageSender used to send and being notified of messages
messageSender *common.MessageSender
// registrationLoopQuitChan is a channel to indicate to the registration loop that should be terminating
registrationLoopQuitChan chan struct{}
// resendingLoopQuitChan is a channel to indicate to the send loop that should be terminating
resendingLoopQuitChan chan struct{}
quit chan struct{}
// registrationSubscriptions is a list of chan of client subscribed to the registration event
registrationSubscriptions []chan struct{}
// pendingRegistrations is a map of pending registrations.
// in theory we should store them in the database, but for now we can keep them in memory at
// the cost of having to register multiple times in case the program stops
pendingRegistrations map[string]bool
}
func New(persistence *Persistence, config *Config, sender *common.MessageSender, messagePersistence MessagePersistence) *Client {
return &Client{
quit: make(chan struct{}),
config: config,
messageSender: sender,
messagePersistence: messagePersistence,
persistence: persistence,
pendingRegistrations: make(map[string]bool),
reader: rand.Reader,
}
}
func (c *Client) Start() error {
if c.messageSender == nil {
return errors.New("can't start, missing message sender")
}
err := c.loadLastPushNotificationRegistration()
if err != nil {
return err
}
c.subscribeForMessageEvents()
// We start even if push notifications are disabled, as we might
// actually be sending an unregister message
c.startRegistrationLoop()
c.startResendingLoop()
return nil
}
func (c *Client) Offline() {
c.stopRegistrationLoop()
c.stopResendingLoop()
}
func (c *Client) Online() {
c.startRegistrationLoop()
c.startResendingLoop()
}
func (c *Client) publishOnRegistrationSubscriptions() {
// Publish on channels, drop if buffer is full
for _, s := range c.registrationSubscriptions {
select {
case s <- struct{}{}:
default:
c.config.Logger.Warn("subscription channel full, dropping message")
}
}
}
func (c *Client) quitRegistrationSubscriptions() {
for _, s := range c.registrationSubscriptions {
close(s)
}
}
func (c *Client) Stop() error {
close(c.quit)
c.stopRegistrationLoop()
c.stopResendingLoop()
c.quitRegistrationSubscriptions()
return nil
}
// Unregister unregisters from all the servers
func (c *Client) Unregister() error {
// stop registration loop
c.stopRegistrationLoop()
c.config.RemoteNotificationsEnabled = false
registration := c.buildPushNotificationUnregisterMessage()
err := c.saveLastPushNotificationRegistration(registration, nil)
if err != nil {
return err
}
// reset servers
err = c.resetServers()
if err != nil {
return err
}
// and asynchronously register
c.startRegistrationLoop()
return nil
}
// Registered returns true if we registered with all the servers
func (c *Client) Registered() (bool, error) {
servers, err := c.persistence.GetServers()
if err != nil {
return false, err
}
for _, s := range servers {
if !s.Registered {
return false, nil
}
}
return true, nil
}
func (c *Client) SubscribeToRegistrations() chan struct{} {
s := make(chan struct{}, 100)
c.registrationSubscriptions = append(c.registrationSubscriptions, s)
return s
}
func (c *Client) GetSentNotification(hashedPublicKey []byte, installationID string, messageID []byte) (*SentNotification, error) {
return c.persistence.GetSentNotification(hashedPublicKey, installationID, messageID)
}
func (c *Client) GetServers() ([]*PushNotificationServer, error) {
return c.persistence.GetServers()
}
func (c *Client) Reregister(options *RegistrationOptions) error {
c.config.Logger.Debug("re-registering")
if len(c.deviceToken) == 0 {
c.config.Logger.Info("no device token, not registering")
return nil
}
if !c.config.RemoteNotificationsEnabled {
c.config.Logger.Info("remote notifications not enabled, not registering")
return nil
}
return c.Register(c.deviceToken, c.apnTopic, c.tokenType, options)
}
// pickDefaultServesr picks n servers at random
func (c *Client) pickDefaultServers(servers []*ecdsa.PublicKey) []*ecdsa.PublicKey {
// shuffle and pick n at random
shuffledServers := make([]*ecdsa.PublicKey, len(servers))
copy(shuffledServers, c.config.DefaultServers)
mrand.Seed(time.Now().Unix())
mrand.Shuffle(len(shuffledServers), func(i, j int) {
shuffledServers[i], shuffledServers[j] = shuffledServers[j], shuffledServers[i]
})
// Take the min not to get an out of bounds slice
min := len(c.config.DefaultServers)
if min > defaultPushNotificationsServersCount {
min = defaultPushNotificationsServersCount
}
return shuffledServers[:min]
}
// Register registers with all the servers
func (c *Client) Register(deviceToken, apnTopic string, tokenType protobuf.PushNotificationRegistration_TokenType, options *RegistrationOptions) error {
// stop registration loop
c.stopRegistrationLoop()
c.config.RemoteNotificationsEnabled = true
// check if we need to fallback on default servers
currentServers, err := c.persistence.GetServers()
if err != nil {
return err
}
if len(currentServers) == 0 && len(c.config.DefaultServers) != 0 {
c.config.Logger.Debug("servers empty, checking default servers")
for _, s := range c.pickDefaultServers(c.config.DefaultServers) {
err = c.AddPushNotificationsServer(s, ServerTypeDefault)
if err != nil {
return err
}
}
}
// reset servers
err = c.resetServers()
if err != nil {
return err
}
c.deviceToken = deviceToken
c.apnTopic = apnTopic
c.tokenType = tokenType
registration, err := c.buildPushNotificationRegistrationMessage(options)
if err != nil {
return err
}
err = c.saveLastPushNotificationRegistration(registration, options.ContactIDs)
if err != nil {
return err
}
c.startRegistrationLoop()
return nil
}
// HandlePushNotificationRegistrationResponse should check whether the response was successful or not, retry if necessary otherwise store the result in the database
func (c *Client) HandlePushNotificationRegistrationResponse(publicKey *ecdsa.PublicKey, response *protobuf.PushNotificationRegistrationResponse) error {
if response == nil {
return nil
}
c.config.Logger.Debug("received push notification registration response", zap.Any("response", response))
if len(response.RequestId) == 0 {
return errors.New("empty requestId")
}
if !c.pendingRegistrations[hex.EncodeToString(response.RequestId)] {
return errors.New("not for one of our requests")
}
// Not successful ignore for now
if !response.Success {
return errors.New("response was not successful")
}
servers, err := c.persistence.GetServersByPublicKey([]*ecdsa.PublicKey{publicKey})
if err != nil {
return err
}
// we haven't registered with this server
if len(servers) != 1 {
return errors.New("not registered with this server, ignoring")
}
server := servers[0]
server.Registered = true
server.RegisteredAt = time.Now().Unix()
err = c.persistence.UpsertServer(server)
if err != nil {
return err
}
c.publishOnRegistrationSubscriptions()
return nil
}
// processQueryInfo takes info about push notifications and validates them
func (c *Client) processQueryInfo(clientPublicKey *ecdsa.PublicKey, serverPublicKey *ecdsa.PublicKey, info *protobuf.PushNotificationQueryInfo) error {
// make sure the public key matches
if !bytes.Equal(info.PublicKey, common.HashPublicKey(clientPublicKey)) {
c.config.Logger.Warn("reply for different key, ignoring")
return errors.New("reply for a different key, ignoring")
}
accessToken := info.AccessToken
// the user wants notification from contacts only, try to decrypt the access token to see if we are in their contacts
if len(accessToken) == 0 && len(info.AllowedKeyList) != 0 {
accessToken = c.handleAllowedKeyList(clientPublicKey, info.AllowedKeyList)
}
// no luck
if len(accessToken) == 0 {
c.config.Logger.Debug("not in the allowed key list")
return nil
}
// We check the user has allowed this server to store this particular
// access token, otherwise anyone could reply with a fake token
// and receive notifications for a user
if err := c.handleGrant(clientPublicKey, serverPublicKey, info.Grant, accessToken); err != nil {
c.config.Logger.Warn("grant verification failed, ignoring", zap.Error(err))
return err
}
pushNotificationInfo := &PushNotificationInfo{
PublicKey: clientPublicKey,
ServerPublicKey: serverPublicKey,
AccessToken: accessToken,
InstallationID: info.InstallationId,
Version: info.Version,
RetrievedAt: time.Now().Unix(),
}
err := c.persistence.SavePushNotificationInfo([]*PushNotificationInfo{pushNotificationInfo})
if err != nil {
c.config.Logger.Error("failed to save push notifications", zap.Error(err))
return err
}
return nil
}
// HandlePushNotificationQueryResponse should update the data in the database for a given user
func (c *Client) HandlePushNotificationQueryResponse(serverPublicKey *ecdsa.PublicKey, response *protobuf.PushNotificationQueryResponse) error {
c.config.Logger.Debug("received push notification query response", zap.Any("response", response))
if response == nil || len(response.Info) == 0 {
return errors.New("empty response from the server")
}
// get the public key associated with this query
clientPublicKey, err := c.persistence.GetQueryPublicKey(response.MessageId)
if err != nil {
c.config.Logger.Error("failed to query client publicKey", zap.Error(err))
return err
}
if clientPublicKey == nil {
c.config.Logger.Debug("query not found")
return nil
}
// process query, make sure to validate grant as coming from the server
for _, info := range response.Info {
err := c.processQueryInfo(clientPublicKey, serverPublicKey, info)
if err != nil {
c.config.Logger.Warn("failed to process info", zap.Any("info", info), zap.Error(err))
continue
}
}
return nil
}
// HandleContactCodeAdvertisement checks if there are any info and process them
func (c *Client) HandleContactCodeAdvertisement(clientPublicKey *ecdsa.PublicKey, message *protobuf.ContactCodeAdvertisement) error {
if message == nil {
return nil
}
// nothing to do for our own pubkey
if common.IsPubKeyEqual(clientPublicKey, &c.config.Identity.PublicKey) {
return nil
}
c.config.Logger.Debug("received contact code advertisement", zap.Any("advertisement", message))
for _, info := range message.PushNotificationInfo {
c.config.Logger.Debug("handling push notification query info")
serverPublicKey, err := crypto.DecompressPubkey(info.ServerPublicKey)
if err != nil {
c.config.Logger.Error("could not unmarshal server pubkey", zap.Binary("server-key", info.ServerPublicKey))
return err
}
err = c.processQueryInfo(clientPublicKey, serverPublicKey, info)
if err != nil {
return err
}
}
// Save query so that we won't query again to early
// NOTE: this is not very accurate as we might fetch an historical message,
// prolonging the time that we fetch new info.
// Most of the times it should work fine, as if the info are stale they'd be
// fetched again because of an error response from the push notification server
return c.persistence.SavePushNotificationQuery(clientPublicKey, []byte(uuid.New().String()))
}
// HandlePushNotificationResponse should set the request as processed
func (c *Client) HandlePushNotificationResponse(serverKey *ecdsa.PublicKey, response *protobuf.PushNotificationResponse) error {
if response == nil {
return nil
}
messageID := response.MessageId
c.config.Logger.Debug("received response for", zap.String("messageID", types.EncodeHex(messageID)))
for _, report := range response.Reports {
c.config.Logger.Debug("received response", zap.Any("report", report))
err := c.persistence.UpdateNotificationResponse(messageID, report)
if err != nil {
return err
}
}
// Restart resending loop, in case we need to resend some notifications
c.stopResendingLoop()
c.startResendingLoop()
return nil
}
func (c *Client) RemovePushNotificationServer(publicKey *ecdsa.PublicKey) error {
c.config.Logger.Debug("removing push notification server", zap.Any("public-key", publicKey))
//TODO: this needs implementing. It requires unregistering from the server and
// likely invalidate the device token of the user
return errors.New("not implemented")
}
func (c *Client) AddPushNotificationsServer(publicKey *ecdsa.PublicKey, serverType ServerType) error {
c.config.Logger.Debug("adding push notifications server", zap.Any("public-key", publicKey))
currentServers, err := c.persistence.GetServers()
if err != nil {
return err
}
for _, server := range currentServers {
if common.IsPubKeyEqual(server.PublicKey, publicKey) {
return errors.New("push notification server already added")
}
}
err = c.persistence.UpsertServer(&PushNotificationServer{
PublicKey: publicKey,
Type: serverType,
})
if err != nil {
return err
}
if c.config.RemoteNotificationsEnabled {
c.startRegistrationLoop()
}
return nil
}
func (c *Client) GetPushNotificationInfo(publicKey *ecdsa.PublicKey, installationIDs []string) ([]*PushNotificationInfo, error) {
if len(installationIDs) == 0 {
return c.persistence.GetPushNotificationInfoByPublicKey(publicKey)
}
return c.persistence.GetPushNotificationInfo(publicKey, installationIDs)
}
func (c *Client) Enabled() bool {
return c.config.RemoteNotificationsEnabled
}
func (c *Client) EnableSending() {
c.config.SendEnabled = true
}
func (c *Client) DisableSending() {
c.config.SendEnabled = false
}
func (c *Client) EnablePushNotificationsFromContactsOnly(options *RegistrationOptions) error {
c.config.Logger.Debug("enabling push notification from contacts only")
c.config.AllowFromContactsOnly = true
if c.lastPushNotificationRegistration != nil && c.config.RemoteNotificationsEnabled {
c.config.Logger.Debug("re-registering after enabling push notifications from contacts only")
return c.Register(c.deviceToken, c.apnTopic, c.tokenType, options)
}
return nil
}
func (c *Client) DisablePushNotificationsFromContactsOnly(options *RegistrationOptions) error {
c.config.Logger.Debug("disabling push notification from contacts only")
c.config.AllowFromContactsOnly = false
if c.lastPushNotificationRegistration != nil && c.config.RemoteNotificationsEnabled {
c.config.Logger.Debug("re-registering after disabling push notifications from contacts only")
return c.Register(c.deviceToken, c.apnTopic, c.tokenType, options)
}
return nil
}
func (c *Client) EnablePushNotificationsBlockMentions(options *RegistrationOptions) error {
c.config.Logger.Debug("disabling push notifications for mentions")
c.config.BlockMentions = true
if c.lastPushNotificationRegistration != nil && c.config.RemoteNotificationsEnabled {
c.config.Logger.Debug("re-registering after disabling push notifications for mentions")
return c.Register(c.deviceToken, c.apnTopic, c.tokenType, options)
}
return nil
}
func (c *Client) DisablePushNotificationsBlockMentions(options *RegistrationOptions) error {
c.config.Logger.Debug("enabling push notifications for mentions")
c.config.BlockMentions = false
if c.lastPushNotificationRegistration != nil && c.config.RemoteNotificationsEnabled {
c.config.Logger.Debug("re-registering after enabling push notifications for mentions")
return c.Register(c.deviceToken, c.apnTopic, c.tokenType, options)
}
return nil
}
func encryptAccessToken(plaintext []byte, key []byte, reader io.Reader) ([]byte, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
if _, err = io.ReadFull(reader, nonce); err != nil {
return nil, err
}
return gcm.Seal(nonce, nonce, plaintext, nil), nil
}
func (c *Client) encryptRegistration(publicKey *ecdsa.PublicKey, payload []byte) ([]byte, error) {
sharedKey, err := c.generateSharedKey(publicKey)
if err != nil {
return nil, err
}
return common.Encrypt(payload, sharedKey, c.reader)
}
func (c *Client) generateSharedKey(publicKey *ecdsa.PublicKey) ([]byte, error) {
return ecies.ImportECDSA(c.config.Identity).GenerateShared(
ecies.ImportECDSAPublic(publicKey),
encryptedPayloadKeyLength,
encryptedPayloadKeyLength,
)
}
// subscribeForMessageEvents subscribes for newly sent/scheduled messages so we can check if we need to send a push notification
func (c *Client) subscribeForMessageEvents() {
go func() {
c.config.Logger.Debug("subscribing for message events")
messageEventsSubscription := c.messageSender.SubscribeToMessageEvents()
for {
select {
case m, more := <-messageEventsSubscription:
if !more {
c.config.Logger.Debug("no more message events, quitting")
return
}
switch m.Type {
case common.MessageScheduled:
c.config.Logger.Debug("handling message scheduled")
if err := c.handleMessageScheduled(m); err != nil {
c.config.Logger.Error("failed to handle message", zap.Error(err))
}
case common.MessageSent:
c.config.Logger.Debug("handling message sent")
if err := c.handleMessageSent(m); err != nil {
c.config.Logger.Error("failed to handle message", zap.Error(err))
}
default:
c.config.Logger.Warn("message event type not supported")
}
case <-c.quit:
return
}
}
}()
}
// loadLastPushNotificationRegistration loads from the database the last registration
func (c *Client) loadLastPushNotificationRegistration() error {
lastRegistration, lastContactIDs, err := c.persistence.GetLastPushNotificationRegistration()
if err != nil {
return err
}
if lastRegistration == nil {
lastRegistration = &protobuf.PushNotificationRegistration{}
}
c.lastContactIDs = lastContactIDs
c.lastPushNotificationRegistration = lastRegistration
c.deviceToken = lastRegistration.DeviceToken
c.apnTopic = lastRegistration.ApnTopic
c.tokenType = lastRegistration.TokenType
return nil
}
func (c *Client) stopRegistrationLoop() {
// stop old registration loop
if c.registrationLoopQuitChan != nil {
close(c.registrationLoopQuitChan)
c.registrationLoopQuitChan = nil
}
}
func (c *Client) stopResendingLoop() {
// stop old registration loop
if c.resendingLoopQuitChan != nil {
close(c.resendingLoopQuitChan)
c.resendingLoopQuitChan = nil
}
}
func (c *Client) startRegistrationLoop() {
c.stopRegistrationLoop()
c.registrationLoopQuitChan = make(chan struct{})
go func() {
err := c.registrationLoop()
if err != nil {
c.config.Logger.Error("registration loop exited with an error", zap.Error(err))
}
}()
}
func (c *Client) startResendingLoop() {
c.stopResendingLoop()
c.resendingLoopQuitChan = make(chan struct{})
go func() {
err := c.resendingLoop()
if err != nil {
c.config.Logger.Error("resending loop exited with an error", zap.Error(err))
}
}()
}
// queryNotificationInfo will block and query for the client token, if force is set it
// will ignore the cool off period
func (c *Client) queryNotificationInfo(publicKey *ecdsa.PublicKey, force bool) error {
c.config.Logger.Debug("retrieving queried at")
// Check if we queried recently
queriedAt, err := c.persistence.GetQueriedAt(publicKey)
if err != nil {
c.config.Logger.Error("failed to retrieve queried at", zap.Error(err))
return err
}
c.config.Logger.Debug("checking if querying necessary")
// Naively query again if too much time has passed.
// Here it might not be necessary
if force || time.Now().Unix()-queriedAt > staleQueryTimeInSeconds {
c.config.Logger.Debug("querying info")
err := c.queryPushNotificationInfo(publicKey)
if err != nil {
c.config.Logger.Error("could not query pn info", zap.Error(err))
return err
}
// This is just horrible, but for now will do,
// the issue is that we don't really know how long it will
// take to reply, as there might be multiple servers
// replying to us.
// The only time we are 100% certain that we can proceed is
// when we have non-stale info for each device, but
// most devices are not going to be registered, so we'd still
// have to wait the maximum amount of time allowed.
// A better way to handle this is to set a maximum timer of say
// 3 seconds, but act at a tick every 200ms.
// That way we still are able to batch multiple push notifications
// but we don't have to wait every time 3 seconds, which is wasteful
// This probably will have to be addressed before released
time.Sleep(3 * time.Second)
}
return nil
}
// handleMessageSent is called every time a message is sent
func (c *Client) handleMessageSent(e *common.MessageEvent) error {
sentMessage := e.SentMessage
// Ignore if we are not sending notifications
if !c.config.SendEnabled {
return nil
}
// check if it's for one of our devices, do nothing in that case
if e.Recipient != nil && common.IsPubKeyEqual(e.Recipient, &c.config.Identity.PublicKey) {
return nil
}
if sentMessage.PublicKey == nil {
return c.handlePublicMessageSent(sentMessage)
}
return c.handleDirectMessageSent(sentMessage)
}
// saving to the database might happen after we fetch the message, so we retry
// for a reasonable amount of time before giving up
func (c *Client) getMessage(messageID string) (*common.Message, error) {
retries := 0
for retries < 10 {
message, err := c.messagePersistence.MessageByID(messageID)
if err == common.ErrRecordNotFound {
retries++
time.Sleep(300 * time.Millisecond)
continue
} else if err != nil {
return nil, err
}
return message, nil
}
return nil, common.ErrRecordNotFound
}
// handlePublicMessageSent handles public messages, we notify only on mentions
func (c *Client) handlePublicMessageSent(sentMessage *common.SentMessage) error {
// We always expect a single message, as we never batch them
if len(sentMessage.MessageIDs) != 1 {
return errors.New("batched public messages not handled")
}
messageID := sentMessage.MessageIDs[0]
c.config.Logger.Debug("handling public messages", zap.Binary("messageID", messageID))
tracked, err := c.persistence.TrackedMessage(messageID)
if err != nil {
return err
}
if !tracked {
c.config.Logger.Debug("messageID not tracked, nothing to do", zap.Binary("messageID", messageID))
}
c.config.Logger.Debug("messageID tracked", zap.Binary("messageID", messageID))
message, err := c.getMessage(types.EncodeHex(messageID))
if err != nil {
c.config.Logger.Error("could not retrieve message", zap.Error(err))
}
// This might happen if the user deleted their messages for example
if message == nil {
c.config.Logger.Warn("message not retrieved")
return nil
}
c.config.Logger.Debug("message found", zap.Binary("messageID", messageID))
for _, pkString := range message.Mentions {
c.config.Logger.Debug("handling mention", zap.String("publickey", pkString))
pubkeyBytes, err := types.DecodeHex(pkString)
if err != nil {
return err
}
publicKey, err := crypto.UnmarshalPubkey(pubkeyBytes)
if err != nil {
return err
}
// we use a synthetic installationID for mentions, as all devices need to be notified
shouldNotify, err := c.shouldNotifyOn(publicKey, mentionInstallationID, messageID)
if err != nil {
return err
}
c.config.Logger.Debug("should no mention", zap.Any("publickey", shouldNotify))
// we send the notifications and return the info of the devices notified
infos, err := c.SendNotification(publicKey, nil, messageID, message.LocalChatID, protobuf.PushNotification_MENTION)
if err != nil {
return err
}
// mark message as sent so we don't notify again
for _, i := range infos {
c.config.Logger.Debug("marking as sent ", zap.Binary("mid", messageID), zap.String("id", i.InstallationID))
if err := c.notifiedOn(publicKey, i.InstallationID, messageID, message.LocalChatID, protobuf.PushNotification_MESSAGE); err != nil {
return err
}
}
}
return nil
}
// handleDirectMessageSent handles one to ones and private group chat messages
// It will check if we need to notify on the message, and if so it will try to
// dispatch a push notification messages might be batched, if coming
// from datasync for example.
func (c *Client) handleDirectMessageSent(sentMessage *common.SentMessage) error {
c.config.Logger.Debug("handling direct messages", zap.Any("messageIDs", sentMessage.MessageIDs))
publicKey := sentMessage.PublicKey
// Collect the messageIDs we want to notify on
var trackedMessageIDs [][]byte
for _, messageID := range sentMessage.MessageIDs {
tracked, err := c.persistence.TrackedMessage(messageID)
if err != nil {
return err
}
if tracked {
trackedMessageIDs = append(trackedMessageIDs, messageID)
}
}
// Nothing to do
if len(trackedMessageIDs) == 0 {
c.config.Logger.Debug("nothing to do for", zap.Any("messageIDs", sentMessage.MessageIDs))
return nil
}
// sendToAllDevices indicates whether the message has been sent using public key encryption only
// i.e not through the double ratchet. In that case, any device will have received it.
sendToAllDevices := len(sentMessage.Spec.Installations) == 0
var installationIDs []string
anyActionableMessage := sendToAllDevices
// Check if we should be notifiying those installations
for _, messageID := range trackedMessageIDs {
for _, installation := range sentMessage.Spec.Installations {
installationID := installation.ID
shouldNotify, err := c.shouldNotifyOn(publicKey, installationID, messageID)
if err != nil {
return err
}
if shouldNotify {
anyActionableMessage = true
installationIDs = append(installationIDs, installation.ID)
}
}
}
// Is there anything we should be notifying on?
if !anyActionableMessage {
c.config.Logger.Debug("no actionable installation IDs")
return nil
}
c.config.Logger.Debug("actionable messages", zap.Any("messageIDs", trackedMessageIDs), zap.Any("installation-ids", installationIDs))
// Get message to check chatID. Again we use the first message for simplicity, but we should send one for each chatID. Messages though are very rarely batched.
message, err := c.getMessage(types.EncodeHex(trackedMessageIDs[0]))
if err != nil {
return err
}
// This is not the prettiest.
// because chatIDs are asymettric, we need to check if it's a one-to-one message or a group chat message.
// to do that we fingerprint the chatID.
// If it's a public key, we use our own public key as chatID, which correspond to the chatID used by the other peer
// otherwise we use the group chat ID
var chatID string
if len(message.ChatId) == oneToOneChatIDLength {
chatID = types.EncodeHex(crypto.FromECDSAPub(&c.config.Identity.PublicKey))
} else {
// this is a group chat
chatID = message.ChatId
}
// we send the notifications and return the info of the devices notified
infos, err := c.SendNotification(publicKey, installationIDs, trackedMessageIDs[0], chatID, protobuf.PushNotification_MESSAGE)
if err != nil {
return err
}
// mark message as sent so we don't notify again
for _, i := range infos {
for _, messageID := range trackedMessageIDs {
c.config.Logger.Debug("marking as sent ", zap.Binary("mid", messageID), zap.String("id", i.InstallationID))
if err := c.notifiedOn(publicKey, i.InstallationID, messageID, chatID, protobuf.PushNotification_MESSAGE); err != nil {
return err
}
}
}
return nil
}
// handleMessageScheduled keeps track of the message to make sure we notify on it
func (c *Client) handleMessageScheduled(e *common.MessageEvent) error {
message := e.RawMessage
if !message.SendPushNotification {
return nil
}
// check if it's for one of our devices, do nothing in that case
if e.Recipient != nil && common.IsPubKeyEqual(e.Recipient, &c.config.Identity.PublicKey) {
return nil
}
messageID, err := types.DecodeHex(message.ID)
if err != nil {
return err
}
return c.persistence.TrackPushNotification(message.LocalChatID, messageID)
}
// shouldNotifyOn check whether we should notify a particular public-key/installation-id/message-id combination
func (c *Client) shouldNotifyOn(publicKey *ecdsa.PublicKey, installationID string, messageID []byte) (bool, error) {
if publicKey != nil && common.IsPubKeyEqual(publicKey, &c.config.Identity.PublicKey) {
return false, nil
}
if len(installationID) == 0 {
return c.persistence.ShouldSendNotificationToAllInstallationIDs(publicKey, messageID)
}
return c.persistence.ShouldSendNotificationFor(publicKey, installationID, messageID)
}
// notifiedOn marks a combination of publickey/installationid/messageID/chatID/type as notified
func (c *Client) notifiedOn(publicKey *ecdsa.PublicKey, installationID string, messageID []byte, chatID string, notificationType protobuf.PushNotification_PushNotificationType) error {
return c.persistence.UpsertSentNotification(&SentNotification{
PublicKey: publicKey,
LastTriedAt: time.Now().Unix(),
InstallationID: installationID,
MessageID: messageID,
ChatID: chatID,
NotificationType: notificationType,
})
}
func (c *Client) chatIDsHashes(chatIDs []string) [][]byte {
var mutedChatListHashes [][]byte
for _, chatID := range chatIDs {
mutedChatListHashes = append(mutedChatListHashes, common.Shake256([]byte(chatID)))
}
return mutedChatListHashes
}
func (c *Client) encryptToken(publicKey *ecdsa.PublicKey, token []byte) ([]byte, error) {
sharedKey, err := ecies.ImportECDSA(c.config.Identity).GenerateShared(
ecies.ImportECDSAPublic(publicKey),
accessTokenKeyLength,
accessTokenKeyLength,
)
if err != nil {
return nil, err
}
encryptedToken, err := encryptAccessToken(token, sharedKey, c.reader)
if err != nil {
return nil, err
}
return encryptedToken, nil
}
func (c *Client) decryptToken(publicKey *ecdsa.PublicKey, token []byte) ([]byte, error) {
sharedKey, err := ecies.ImportECDSA(c.config.Identity).GenerateShared(
ecies.ImportECDSAPublic(publicKey),
accessTokenKeyLength,
accessTokenKeyLength,
)
if err != nil {
return nil, err
}
decryptedToken, err := common.Decrypt(token, sharedKey)
if err != nil {
return nil, err
}
return decryptedToken, nil
}
// allowedKeyList builds up a list of encrypted tokens, used for registering with the server
func (c *Client) allowedKeyList(token []byte, contactIDs []*ecdsa.PublicKey) ([][]byte, error) {
// If we allow everyone, don't set the list
if !c.config.AllowFromContactsOnly {
return nil, nil
}
var encryptedTokens [][]byte
for _, publicKey := range contactIDs {
encryptedToken, err := c.encryptToken(publicKey, token)
if err != nil {
return nil, err
}
encryptedTokens = append(encryptedTokens, encryptedToken)
}
return encryptedTokens, nil
}
// getToken checks if we need to refresh the token
// and return a new one in that case. A token is refreshed only if it's not set
// or if a contact has been removed
func (c *Client) getToken(contactIDs []*ecdsa.PublicKey) string {
if c.lastPushNotificationRegistration == nil || len(c.lastPushNotificationRegistration.AccessToken) == 0 || c.shouldRefreshToken(c.lastContactIDs, contactIDs, c.lastPushNotificationRegistration.AllowFromContactsOnly, c.config.AllowFromContactsOnly) {
c.config.Logger.Info("refreshing access token")
return uuid.New().String()
}
return c.lastPushNotificationRegistration.AccessToken
}
func (c *Client) getVersion() uint64 {
if c.lastPushNotificationRegistration == nil {
return 1
}
return c.lastPushNotificationRegistration.Version + 1
}
func (c *Client) buildPushNotificationRegistrationMessage(options *RegistrationOptions) (*protobuf.PushNotificationRegistration, error) {
token := c.getToken(options.ContactIDs)
allowedKeyList, err := c.allowedKeyList([]byte(token), options.ContactIDs)
if err != nil {
return nil, err
}
return &protobuf.PushNotificationRegistration{
AccessToken: token,
TokenType: c.tokenType,
ApnTopic: c.apnTopic,
Version: c.getVersion(),
InstallationId: c.config.InstallationID,
DeviceToken: c.deviceToken,
AllowFromContactsOnly: c.config.AllowFromContactsOnly,
Enabled: c.config.RemoteNotificationsEnabled,
BlockedChatList: c.chatIDsHashes(options.BlockedChatIDs),
BlockMentions: c.config.BlockMentions,
AllowedMentionsChatList: c.chatIDsHashes(options.PublicChatIDs),
AllowedKeyList: allowedKeyList,
MutedChatList: c.chatIDsHashes(options.MutedChatIDs),
}, nil
}
func (c *Client) buildPushNotificationUnregisterMessage() *protobuf.PushNotificationRegistration {
options := &protobuf.PushNotificationRegistration{
Version: c.getVersion(),
InstallationId: c.config.InstallationID,
Unregister: true,
}
return options
}
// shouldRefreshToken tells us whether we should create a new token,
// that's only necessary when a contact is removed
// or allowFromContactsOnly is enabled.
// In both cases we want to invalidate any existing token
func (c *Client) shouldRefreshToken(oldContactIDs, newContactIDs []*ecdsa.PublicKey, oldAllowFromContactsOnly, newAllowFromContactsOnly bool) bool {
// Check if allowFromContactsOnly has just been enabled
if !oldAllowFromContactsOnly && newAllowFromContactsOnly {
return true
}
newContactIDsMap := make(map[string]bool)
for _, pk := range newContactIDs {
newContactIDsMap[types.EncodeHex(crypto.FromECDSAPub(pk))] = true
}
for _, pk := range oldContactIDs {
if ok := newContactIDsMap[types.EncodeHex(crypto.FromECDSAPub(pk))]; !ok {
return true
}
}
return false
}
func nextServerRetry(server *PushNotificationServer) int64 {
return server.LastRetriedAt + RegistrationBackoffTime*server.RetryCount*int64(math.Exp2(float64(server.RetryCount)))
}
func nextPushNotificationRetry(pn *SentNotification) int64 {
return pn.LastTriedAt + pushNotificationBackoffTime*pn.RetryCount*int64(math.Exp2(float64(pn.RetryCount)))
}
// We calculate if it's too early to retry, by exponentially backing off
func shouldRetryRegisteringWithServer(server *PushNotificationServer) bool {
return time.Now().Unix() >= nextServerRetry(server)
}
// We calculate if it's too early to retry, by exponentially backing off
func shouldRetryPushNotification(pn *SentNotification) bool {
if pn.RetryCount > maxPushNotificationRetries {
return false
}
return time.Now().Unix() >= nextPushNotificationRetry(pn)
}
func (c *Client) resetServers() error {
servers, err := c.persistence.GetServers()
if err != nil {
return err
}
for _, server := range servers {
// Reset server registration data
server.Registered = false
server.RegisteredAt = 0
server.RetryCount = 0
server.LastRetriedAt = time.Now().Unix()
server.AccessToken = ""
if err := c.persistence.UpsertServer(server); err != nil {
return err
}
}
return nil
}
// registerWithServer will register with a push notification server. This will use
// the user identity key for dispatching, as the content is in any case signed, so identity needs to be revealed.
func (c *Client) registerWithServer(registration *protobuf.PushNotificationRegistration, server *PushNotificationServer) error {
// reset server registration data
server.Registered = false
server.RegisteredAt = 0
server.RetryCount++
server.LastRetriedAt = time.Now().Unix()
server.AccessToken = registration.AccessToken
// save
if err := c.persistence.UpsertServer(server); err != nil {
return err
}
// build grant for this specific server
grant, err := c.buildGrantSignature(server.PublicKey, registration.AccessToken)
if err != nil {
c.config.Logger.Error("failed to build grant", zap.Error(err))
return err
}
registration.Grant = grant
// marshal message
marshaledRegistration, err := proto.Marshal(registration)
if err != nil {
return err
}
// encrypt and dispatch message
encryptedRegistration, err := c.encryptRegistration(server.PublicKey, marshaledRegistration)
if err != nil {
return err
}
rawMessage := common.RawMessage{
Payload: encryptedRegistration,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_REGISTRATION,
// We send on personal topic to avoid a lot of traffic on the partitioned topic
SendOnPersonalTopic: true,
SkipEncryptionLayer: true,
}
_, err = c.messageSender.SendPrivate(context.Background(), server.PublicKey, &rawMessage)
if err != nil {
return err
}
c.pendingRegistrations[hex.EncodeToString(common.Shake256(encryptedRegistration))] = true
return nil
}
// SendNotification sends an actual notification to the push notification server.
// the notification is sent using an ephemeral key to shield the real identity of the sender
func (c *Client) SendNotification(publicKey *ecdsa.PublicKey, installationIDs []string, messageID []byte, chatID string, notificationType protobuf.PushNotification_PushNotificationType) ([]*PushNotificationInfo, error) {
if common.IsPubKeyEqual(publicKey, &c.config.Identity.PublicKey) {
return nil, nil
}
// get latest push notification infos
err := c.queryNotificationInfo(publicKey, false)
if err != nil {
return nil, err
}
c.config.Logger.Debug("queried info")
// retrieve info from the database
info, err := c.GetPushNotificationInfo(publicKey, installationIDs)
if err != nil {
c.config.Logger.Error("could not get pn info", zap.Error(err))
return nil, err
}
// naively dispatch to the first server for now
// push notifications are only retried for now if a WRONG_TOKEN response is returned.
// we should also retry if no response at all is received after a timeout.
// also we send a single notification for multiple message ids, need to check with UI what's the desired behavior
// shuffle so we don't hit the same servers all the times
// NOTE: here's is a tradeoff, ideally we want to randomly pick a server,
// but hit the same servers for batched notifications, for now naively
// hit a random server
mrand.Seed(time.Now().Unix())
mrand.Shuffle(len(info), func(i, j int) {
info[i], info[j] = info[j], info[i]
})
installationIDsMap := make(map[string]bool)
// one info per installation id, grouped by server
actionableInfos := make(map[string][]*PushNotificationInfo)
for _, i := range info {
if !installationIDsMap[i.InstallationID] {
serverKey := hex.EncodeToString(crypto.CompressPubkey(i.ServerPublicKey))
actionableInfos[serverKey] = append(actionableInfos[serverKey], i)
installationIDsMap[i.InstallationID] = true
}
}
c.config.Logger.Debug("actionable info", zap.Int("count", len(actionableInfos)))
// add ephemeral key and listen to it
ephemeralKey, err := crypto.GenerateKey()
if err != nil {
return nil, err
}
_, err = c.messageSender.AddEphemeralKey(ephemeralKey)
if err != nil {
return nil, err
}
var actionedInfo []*PushNotificationInfo
for _, infos := range actionableInfos {
var pushNotifications []*protobuf.PushNotification
for _, i := range infos {
pushNotifications = append(pushNotifications, &protobuf.PushNotification{
Type: notificationType,
// For now we set the ChatID to our own identity key, this will work fine for blocked users
// and muted 1-to-1 chats, but not for group chats.
ChatId: common.Shake256([]byte(chatID)),
Author: common.Shake256([]byte(types.EncodeHex(crypto.FromECDSAPub(&c.config.Identity.PublicKey)))),
AccessToken: i.AccessToken,
PublicKey: common.HashPublicKey(publicKey),
InstallationId: i.InstallationID,
})
}
request := &protobuf.PushNotificationRequest{
MessageId: messageID,
Requests: pushNotifications,
}
serverPublicKey := infos[0].ServerPublicKey
payload, err := proto.Marshal(request)
if err != nil {
return nil, err
}
rawMessage := common.RawMessage{
Payload: payload,
Sender: ephemeralKey,
// we skip encryption as we don't want to save any key material
// for an ephemeral key, no need to use pfs as these are throw away keys
SkipEncryptionLayer: true,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_REQUEST,
}
_, err = c.messageSender.SendPrivate(context.Background(), serverPublicKey, &rawMessage)
if err != nil {
return nil, err
}
actionedInfo = append(actionedInfo, infos...)
}
return actionedInfo, nil
}
func (c *Client) resendNotification(pn *SentNotification) error {
c.config.Logger.Debug("resending notification")
pn.RetryCount++
pn.LastTriedAt = time.Now().Unix()
err := c.persistence.UpsertSentNotification(pn)
if err != nil {
c.config.Logger.Error("failed to upsert notification", zap.Error(err))
return err
}
// re-fetch push notification info
err = c.queryNotificationInfo(pn.PublicKey, true)
if err != nil {
c.config.Logger.Error("failed to query notification info", zap.Error(err))
return err
}
if err != nil {
c.config.Logger.Error("could not get pn info", zap.Error(err))
return err
}
_, err = c.SendNotification(pn.PublicKey, []string{pn.InstallationID}, pn.MessageID, pn.ChatID, pn.NotificationType)
return err
}
// resendingLoop is a loop that is running when push notifications need to be resent, it only runs when needed, it will quit if no work is necessary.
func (c *Client) resendingLoop() error {
for {
c.config.Logger.Debug("running resending loop")
var lowestNextRetry int64
// fetch retriable notifications
retriableNotifications, err := c.persistence.GetRetriablePushNotifications()
if err != nil {
c.config.Logger.Error("failed retrieving notifications, quitting resending loop", zap.Error(err))
return err
}
if len(retriableNotifications) == 0 {
c.config.Logger.Debug("no retriable notifications, quitting")
return nil
}
c.config.Logger.Debug("have some retriable notifications", zap.Int("retryable-notifications", len(retriableNotifications)))
for _, pn := range retriableNotifications {
// check if we should retry the notification
if shouldRetryPushNotification(pn) {
c.config.Logger.Debug("retrying pn")
err := c.resendNotification(pn)
if err != nil {
return err
}
}
// set the lowest next retry if necessary
nextRetry := nextPushNotificationRetry(pn)
if lowestNextRetry == 0 || nextRetry < lowestNextRetry {
lowestNextRetry = nextRetry
}
}
nextRetry := lowestNextRetry - time.Now().Unix()
// Give some room, sleep at least a second
if nextRetry < 1 {
nextRetry = 1
}
// how long should we sleep for?
waitFor := time.Duration(nextRetry)
select {
case <-time.After(waitFor * time.Second):
case <-c.resendingLoopQuitChan:
return nil
}
}
}
// registrationLoop is a loop that is running when we need to register with a push notification server, it only runs when needed, it will quit if no work is necessary.
func (c *Client) registrationLoop() error {
if c.lastPushNotificationRegistration == nil {
return nil
}
for {
c.config.Logger.Debug("running registration loop")
servers, err := c.persistence.GetServers()
if err != nil {
c.config.Logger.Error("failed retrieving servers, quitting registration loop", zap.Error(err))
return err
}
if len(servers) == 0 {
c.config.Logger.Debug("nothing to do, quitting registration loop")
return nil
}
var nonRegisteredServers []*PushNotificationServer
for _, server := range servers {
if !server.Registered && server.RetryCount < maxRegistrationRetries {
nonRegisteredServers = append(nonRegisteredServers, server)
}
}
if len(nonRegisteredServers) == 0 {
c.config.Logger.Debug("registered with all servers, quitting registration loop")
return nil
}
c.config.Logger.Debug("Trying to register with", zap.Int("servers", len(nonRegisteredServers)))
var lowestNextRetry int64
for _, server := range nonRegisteredServers {
if shouldRetryRegisteringWithServer(server) {
c.config.Logger.Debug("registering with server", zap.Any("server", server))
err := c.registerWithServer(c.lastPushNotificationRegistration, server)
if err != nil {
return err
}
}
nextRetry := nextServerRetry(server)
if lowestNextRetry == 0 || nextRetry < lowestNextRetry {
lowestNextRetry = nextRetry
}
}
nextRetry := lowestNextRetry - time.Now().Unix()
waitFor := time.Duration(nextRetry)
c.config.Logger.Debug("Waiting for", zap.Any("wait for", waitFor))
select {
case <-time.After(waitFor * time.Second):
case <-c.registrationLoopQuitChan:
return nil
}
}
}
func (c *Client) saveLastPushNotificationRegistration(registration *protobuf.PushNotificationRegistration, contactIDs []*ecdsa.PublicKey) error {
// stop registration loop
c.stopRegistrationLoop()
err := c.persistence.SaveLastPushNotificationRegistration(registration, contactIDs)
if err != nil {
return err
}
c.lastPushNotificationRegistration = registration
c.lastContactIDs = contactIDs
return nil
}
// 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 (c *Client) 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)...)
return crypto.Keccak256(signatureMaterial)
}
func (c *Client) buildGrantSignature(serverPublicKey *ecdsa.PublicKey, accessToken string) ([]byte, error) {
signatureMaterial := c.buildGrantSignatureMaterial(&c.config.Identity.PublicKey, serverPublicKey, accessToken)
return crypto.Sign(signatureMaterial, c.config.Identity)
}
func (c *Client) handleGrant(clientPublicKey *ecdsa.PublicKey, serverPublicKey *ecdsa.PublicKey, grant []byte, accessToken string) error {
signatureMaterial := c.buildGrantSignatureMaterial(clientPublicKey, serverPublicKey, accessToken)
extractedPublicKey, err := crypto.SigToPub(signatureMaterial, grant)
if err != nil {
return err
}
if !common.IsPubKeyEqual(clientPublicKey, extractedPublicKey) {
return errors.New("invalid grant")
}
return nil
}
// handleAllowedKeyList will try to decrypt a token from the list, to see if we are allowed to send push notification to a given user
func (c *Client) handleAllowedKeyList(publicKey *ecdsa.PublicKey, allowedKeyList [][]byte) string {
c.config.Logger.Debug("handling allowed key list")
for _, encryptedToken := range allowedKeyList {
token, err := c.decryptToken(publicKey, encryptedToken)
if err != nil {
c.config.Logger.Warn("could not decrypt token", zap.Error(err))
continue
}
c.config.Logger.Debug("decrypted token")
return string(token)
}
return ""
}
func (c *Client) MyPushNotificationQueryInfo() ([]*protobuf.PushNotificationQueryInfo, error) {
// Nothing to do
if c.lastPushNotificationRegistration == nil || c.lastPushNotificationRegistration.Unregister {
return nil, nil
}
var response []*protobuf.PushNotificationQueryInfo
servers, err := c.persistence.GetServers()
if err != nil {
return nil, err
}
for _, server := range servers {
// ignore non-registered servers
if !server.Registered {
continue
}
// build grant for this specific server
grant, err := c.buildGrantSignature(server.PublicKey, c.lastPushNotificationRegistration.AccessToken)
if err != nil {
c.config.Logger.Error("failed to build grant", zap.Error(err))
return nil, err
}
queryInfo := &protobuf.PushNotificationQueryInfo{
InstallationId: c.config.InstallationID,
// is this the right key?
PublicKey: common.HashPublicKey(&c.config.Identity.PublicKey),
Version: c.lastPushNotificationRegistration.Version,
Grant: grant,
ServerPublicKey: crypto.CompressPubkey(server.PublicKey),
}
if c.lastPushNotificationRegistration.AllowFromContactsOnly {
queryInfo.AllowedKeyList = c.lastPushNotificationRegistration.AllowedKeyList
} else {
queryInfo.AccessToken = c.lastPushNotificationRegistration.AccessToken
}
response = append(response, queryInfo)
}
return response, nil
}
// queryPushNotificationInfo sends a message to any server who has the given user registered.
// it uses an ephemeral key so the identity of the client querying is not disclosed
func (c *Client) queryPushNotificationInfo(publicKey *ecdsa.PublicKey) error {
hashedPublicKey := common.HashPublicKey(publicKey)
query := &protobuf.PushNotificationQuery{
PublicKeys: [][]byte{hashedPublicKey},
}
encodedMessage, err := proto.Marshal(query)
if err != nil {
return err
}
ephemeralKey, err := crypto.GenerateKey()
if err != nil {
return err
}
rawMessage := common.RawMessage{
Payload: encodedMessage,
Sender: ephemeralKey,
// we don't want to wrap in an encryption layer message
SkipEncryptionLayer: true,
MessageType: protobuf.ApplicationMetadataMessage_PUSH_NOTIFICATION_QUERY,
}
_, err = c.messageSender.AddEphemeralKey(ephemeralKey)
if err != nil {
return err
}
// this is the topic of message
encodedPublicKey := hex.EncodeToString(hashedPublicKey)
messageID, err := c.messageSender.SendPublic(context.Background(), encodedPublicKey, rawMessage)
if err != nil {
return err
}
return c.persistence.SavePushNotificationQuery(publicKey, messageID)
}