422 lines
14 KiB
Go
422 lines
14 KiB
Go
// Copyright (c) 2021 Tulir Asokan
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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package whatsmeow
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import (
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"bytes"
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"compress/zlib"
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"crypto/rand"
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"errors"
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"fmt"
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"io"
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"runtime/debug"
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"strconv"
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"sync/atomic"
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"time"
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"go.mau.fi/libsignal/signalerror"
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"google.golang.org/protobuf/proto"
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"go.mau.fi/libsignal/groups"
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"go.mau.fi/libsignal/protocol"
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"go.mau.fi/libsignal/session"
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"go.mau.fi/whatsmeow/appstate"
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waBinary "go.mau.fi/whatsmeow/binary"
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waProto "go.mau.fi/whatsmeow/binary/proto"
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"go.mau.fi/whatsmeow/store"
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"go.mau.fi/whatsmeow/types"
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"go.mau.fi/whatsmeow/types/events"
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)
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var pbSerializer = store.SignalProtobufSerializer
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func (cli *Client) handleEncryptedMessage(node *waBinary.Node) {
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info, err := cli.parseMessageInfo(node)
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if err != nil {
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cli.Log.Warnf("Failed to parse message: %v", err)
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} else {
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if len(info.PushName) > 0 && info.PushName != "-" {
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go cli.updatePushName(info.Sender, info, info.PushName)
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}
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cli.decryptMessages(info, node)
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}
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}
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func (cli *Client) parseMessageSource(node *waBinary.Node) (source types.MessageSource, err error) {
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from, ok := node.Attrs["from"].(types.JID)
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if !ok {
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err = fmt.Errorf("didn't find valid `from` attribute in message")
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} else if from.Server == types.GroupServer || from.Server == types.BroadcastServer {
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source.IsGroup = true
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source.Chat = from
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sender, ok := node.Attrs["participant"].(types.JID)
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if !ok {
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err = fmt.Errorf("didn't find valid `participant` attribute in group message")
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} else {
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source.Sender = sender
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if source.Sender.User == cli.Store.ID.User {
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source.IsFromMe = true
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}
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}
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if from.Server == types.BroadcastServer {
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recipient, ok := node.Attrs["recipient"].(types.JID)
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if ok {
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source.BroadcastListOwner = recipient
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}
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}
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} else if from.User == cli.Store.ID.User {
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source.IsFromMe = true
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source.Sender = from
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recipient, ok := node.Attrs["recipient"].(types.JID)
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if !ok {
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source.Chat = from.ToNonAD()
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} else {
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source.Chat = recipient
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}
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} else {
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source.Chat = from.ToNonAD()
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source.Sender = from
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}
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return
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}
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func (cli *Client) parseMessageInfo(node *waBinary.Node) (*types.MessageInfo, error) {
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var info types.MessageInfo
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var err error
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var ok bool
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info.MessageSource, err = cli.parseMessageSource(node)
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if err != nil {
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return nil, err
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}
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info.ID, ok = node.Attrs["id"].(string)
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if !ok {
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return nil, fmt.Errorf("didn't find valid `id` attribute in message")
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}
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ts, ok := node.Attrs["t"].(string)
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if !ok {
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return nil, fmt.Errorf("didn't find valid `t` (timestamp) attribute in message")
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}
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tsInt, err := strconv.ParseInt(ts, 10, 64)
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if err != nil {
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return nil, fmt.Errorf("didn't find valid `t` (timestamp) attribute in message: %w", err)
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}
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info.Timestamp = time.Unix(tsInt, 0)
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info.PushName, _ = node.Attrs["notify"].(string)
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info.Category, _ = node.Attrs["category"].(string)
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for _, child := range node.GetChildren() {
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if child.Tag == "multicast" {
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info.Multicast = true
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} else if mediaType, ok := child.AttrGetter().GetString("mediatype", false); ok {
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info.MediaType = mediaType
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}
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}
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return &info, nil
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}
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func (cli *Client) decryptMessages(info *types.MessageInfo, node *waBinary.Node) {
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go cli.sendAck(node)
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if len(node.GetChildrenByTag("unavailable")) > 0 && len(node.GetChildrenByTag("enc")) == 0 {
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cli.Log.Warnf("Unavailable message %s from %s", info.ID, info.SourceString())
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go cli.sendRetryReceipt(node, true)
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cli.dispatchEvent(&events.UndecryptableMessage{Info: *info, IsUnavailable: true})
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return
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}
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children := node.GetChildren()
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cli.Log.Debugf("Decrypting %d messages from %s", len(children), info.SourceString())
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handled := false
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for _, child := range children {
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if child.Tag != "enc" {
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continue
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}
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encType, ok := child.Attrs["type"].(string)
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if !ok {
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continue
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}
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var decrypted []byte
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var err error
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if encType == "pkmsg" || encType == "msg" {
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decrypted, err = cli.decryptDM(&child, info.Sender, encType == "pkmsg")
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} else if info.IsGroup && encType == "skmsg" {
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decrypted, err = cli.decryptGroupMsg(&child, info.Sender, info.Chat)
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} else {
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cli.Log.Warnf("Unhandled encrypted message (type %s) from %s", encType, info.SourceString())
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continue
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}
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if err != nil {
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cli.Log.Warnf("Error decrypting message from %s: %v", info.SourceString(), err)
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go cli.sendRetryReceipt(node, false)
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cli.dispatchEvent(&events.UndecryptableMessage{Info: *info, IsUnavailable: false})
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return
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}
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var msg waProto.Message
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err = proto.Unmarshal(decrypted, &msg)
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if err != nil {
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cli.Log.Warnf("Error unmarshaling decrypted message from %s: %v", info.SourceString(), err)
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continue
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}
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cli.handleDecryptedMessage(info, &msg)
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handled = true
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}
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if handled {
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go cli.sendMessageReceipt(info)
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}
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}
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func (cli *Client) clearUntrustedIdentity(target types.JID) {
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err := cli.Store.Identities.DeleteIdentity(target.SignalAddress().String())
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if err != nil {
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cli.Log.Warnf("Failed to delete untrusted identity of %s from store: %v", target, err)
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}
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err = cli.Store.Sessions.DeleteSession(target.SignalAddress().String())
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if err != nil {
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cli.Log.Warnf("Failed to delete session with %s (untrusted identity) from store: %v", target, err)
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}
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cli.dispatchEvent(&events.IdentityChange{JID: target, Timestamp: time.Now(), Implicit: true})
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}
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func (cli *Client) decryptDM(child *waBinary.Node, from types.JID, isPreKey bool) ([]byte, error) {
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content, _ := child.Content.([]byte)
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builder := session.NewBuilderFromSignal(cli.Store, from.SignalAddress(), pbSerializer)
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cipher := session.NewCipher(builder, from.SignalAddress())
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var plaintext []byte
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if isPreKey {
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preKeyMsg, err := protocol.NewPreKeySignalMessageFromBytes(content, pbSerializer.PreKeySignalMessage, pbSerializer.SignalMessage)
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if err != nil {
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return nil, fmt.Errorf("failed to parse prekey message: %w", err)
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}
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plaintext, _, err = cipher.DecryptMessageReturnKey(preKeyMsg)
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if cli.AutoTrustIdentity && errors.Is(err, signalerror.ErrUntrustedIdentity) {
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cli.Log.Warnf("Got %v error while trying to decrypt prekey message from %s, clearing stored identity and retrying", err, from)
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cli.clearUntrustedIdentity(from)
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plaintext, _, err = cipher.DecryptMessageReturnKey(preKeyMsg)
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}
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if err != nil {
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return nil, fmt.Errorf("failed to decrypt prekey message: %w", err)
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}
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} else {
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msg, err := protocol.NewSignalMessageFromBytes(content, pbSerializer.SignalMessage)
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if err != nil {
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return nil, fmt.Errorf("failed to parse normal message: %w", err)
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}
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plaintext, err = cipher.Decrypt(msg)
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if err != nil {
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return nil, fmt.Errorf("failed to decrypt normal message: %w", err)
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}
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}
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return unpadMessage(plaintext)
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}
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func (cli *Client) decryptGroupMsg(child *waBinary.Node, from types.JID, chat types.JID) ([]byte, error) {
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content, _ := child.Content.([]byte)
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senderKeyName := protocol.NewSenderKeyName(chat.String(), from.SignalAddress())
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builder := groups.NewGroupSessionBuilder(cli.Store, pbSerializer)
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cipher := groups.NewGroupCipher(builder, senderKeyName, cli.Store)
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msg, err := protocol.NewSenderKeyMessageFromBytes(content, pbSerializer.SenderKeyMessage)
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if err != nil {
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return nil, fmt.Errorf("failed to parse group message: %w", err)
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}
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plaintext, err := cipher.Decrypt(msg)
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if err != nil {
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return nil, fmt.Errorf("failed to decrypt group message: %w", err)
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}
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return unpadMessage(plaintext)
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}
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const checkPadding = true
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func isValidPadding(plaintext []byte) bool {
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lastByte := plaintext[len(plaintext)-1]
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expectedPadding := bytes.Repeat([]byte{lastByte}, int(lastByte))
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return bytes.HasSuffix(plaintext, expectedPadding)
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}
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func unpadMessage(plaintext []byte) ([]byte, error) {
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if checkPadding && !isValidPadding(plaintext) {
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return nil, fmt.Errorf("plaintext doesn't have expected padding")
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}
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return plaintext[:len(plaintext)-int(plaintext[len(plaintext)-1])], nil
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}
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func padMessage(plaintext []byte) []byte {
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var pad [1]byte
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_, err := rand.Read(pad[:])
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if err != nil {
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panic(err)
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}
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pad[0] &= 0xf
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if pad[0] == 0 {
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pad[0] = 0xf
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}
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plaintext = append(plaintext, bytes.Repeat(pad[:], int(pad[0]))...)
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return plaintext
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}
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func (cli *Client) handleSenderKeyDistributionMessage(chat, from types.JID, rawSKDMsg *waProto.SenderKeyDistributionMessage) {
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builder := groups.NewGroupSessionBuilder(cli.Store, pbSerializer)
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senderKeyName := protocol.NewSenderKeyName(chat.String(), from.SignalAddress())
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sdkMsg, err := protocol.NewSenderKeyDistributionMessageFromBytes(rawSKDMsg.AxolotlSenderKeyDistributionMessage, pbSerializer.SenderKeyDistributionMessage)
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if err != nil {
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cli.Log.Errorf("Failed to parse sender key distribution message from %s for %s: %v", from, chat, err)
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return
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}
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builder.Process(senderKeyName, sdkMsg)
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cli.Log.Debugf("Processed sender key distribution message from %s in %s", senderKeyName.Sender().String(), senderKeyName.GroupID())
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}
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func (cli *Client) handleHistorySyncNotificationLoop() {
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defer func() {
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atomic.StoreUint32(&cli.historySyncHandlerStarted, 0)
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err := recover()
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if err != nil {
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cli.Log.Errorf("History sync handler panicked: %v\n%s", err, debug.Stack())
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}
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// Check in case something new appeared in the channel between the loop stopping
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// and the atomic variable being updated. If yes, restart the loop.
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if len(cli.historySyncNotifications) > 0 && atomic.CompareAndSwapUint32(&cli.historySyncHandlerStarted, 0, 1) {
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cli.Log.Warnf("New history sync notifications appeared after loop stopped, restarting loop...")
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go cli.handleHistorySyncNotificationLoop()
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}
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}()
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for notif := range cli.historySyncNotifications {
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cli.handleHistorySyncNotification(notif)
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}
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}
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func (cli *Client) handleHistorySyncNotification(notif *waProto.HistorySyncNotification) {
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var historySync waProto.HistorySync
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if data, err := cli.Download(notif); err != nil {
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cli.Log.Errorf("Failed to download history sync data: %v", err)
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} else if reader, err := zlib.NewReader(bytes.NewReader(data)); err != nil {
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cli.Log.Errorf("Failed to create zlib reader for history sync data: %v", err)
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} else if rawData, err := io.ReadAll(reader); err != nil {
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cli.Log.Errorf("Failed to decompress history sync data: %v", err)
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} else if err = proto.Unmarshal(rawData, &historySync); err != nil {
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cli.Log.Errorf("Failed to unmarshal history sync data: %v", err)
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} else {
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cli.Log.Debugf("Received history sync (type %s, chunk %d)", historySync.GetSyncType(), historySync.GetChunkOrder())
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if historySync.GetSyncType() == waProto.HistorySync_PUSH_NAME {
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go cli.handleHistoricalPushNames(historySync.GetPushnames())
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}
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cli.dispatchEvent(&events.HistorySync{
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Data: &historySync,
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})
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}
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}
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func (cli *Client) handleAppStateSyncKeyShare(keys *waProto.AppStateSyncKeyShare) {
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cli.Log.Debugf("Got %d new app state keys", len(keys.GetKeys()))
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for _, key := range keys.GetKeys() {
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marshaledFingerprint, err := proto.Marshal(key.GetKeyData().GetFingerprint())
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if err != nil {
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cli.Log.Errorf("Failed to marshal fingerprint of app state sync key %X", key.GetKeyId().GetKeyId())
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continue
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}
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err = cli.Store.AppStateKeys.PutAppStateSyncKey(key.GetKeyId().GetKeyId(), store.AppStateSyncKey{
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Data: key.GetKeyData().GetKeyData(),
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Fingerprint: marshaledFingerprint,
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Timestamp: key.GetKeyData().GetTimestamp(),
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})
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if err != nil {
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cli.Log.Errorf("Failed to store app state sync key %X", key.GetKeyId().GetKeyId())
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continue
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}
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cli.Log.Debugf("Received app state sync key %X", key.GetKeyId().GetKeyId())
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}
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for _, name := range appstate.AllPatchNames {
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err := cli.FetchAppState(name, false, true)
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if err != nil {
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cli.Log.Errorf("Failed to do initial fetch of app state %s: %v", name, err)
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}
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}
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}
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func (cli *Client) handleProtocolMessage(info *types.MessageInfo, msg *waProto.Message) {
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protoMsg := msg.GetProtocolMessage()
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if protoMsg.GetHistorySyncNotification() != nil && info.IsFromMe {
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cli.historySyncNotifications <- protoMsg.HistorySyncNotification
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if atomic.CompareAndSwapUint32(&cli.historySyncHandlerStarted, 0, 1) {
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go cli.handleHistorySyncNotificationLoop()
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}
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go cli.sendProtocolMessageReceipt(info.ID, "hist_sync")
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}
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if protoMsg.GetAppStateSyncKeyShare() != nil && info.IsFromMe {
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go cli.handleAppStateSyncKeyShare(protoMsg.AppStateSyncKeyShare)
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}
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if info.Category == "peer" {
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go cli.sendProtocolMessageReceipt(info.ID, "peer_msg")
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}
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}
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func (cli *Client) handleDecryptedMessage(info *types.MessageInfo, msg *waProto.Message) {
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evt := &events.Message{Info: *info, RawMessage: msg}
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// First unwrap device sent messages
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if msg.GetDeviceSentMessage().GetMessage() != nil {
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msg = msg.GetDeviceSentMessage().GetMessage()
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evt.Info.DeviceSentMeta = &types.DeviceSentMeta{
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DestinationJID: msg.GetDeviceSentMessage().GetDestinationJid(),
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Phash: msg.GetDeviceSentMessage().GetPhash(),
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}
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}
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if msg.GetSenderKeyDistributionMessage() != nil {
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if !info.IsGroup {
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cli.Log.Warnf("Got sender key distribution message in non-group chat from", info.Sender)
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} else {
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cli.handleSenderKeyDistributionMessage(info.Chat, info.Sender, msg.SenderKeyDistributionMessage)
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}
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}
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if msg.GetProtocolMessage() != nil {
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cli.handleProtocolMessage(info, msg)
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}
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// Unwrap ephemeral and view-once messages
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// Hopefully sender key distribution messages and protocol messages can't be inside ephemeral messages
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if msg.GetEphemeralMessage().GetMessage() != nil {
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msg = msg.GetEphemeralMessage().GetMessage()
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evt.IsEphemeral = true
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}
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if msg.GetViewOnceMessage().GetMessage() != nil {
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msg = msg.GetViewOnceMessage().GetMessage()
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evt.IsViewOnce = true
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}
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evt.Message = msg
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cli.dispatchEvent(evt)
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}
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func (cli *Client) sendProtocolMessageReceipt(id, msgType string) {
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if len(id) == 0 || cli.Store.ID == nil {
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return
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}
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err := cli.sendNode(waBinary.Node{
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Tag: "receipt",
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Attrs: waBinary.Attrs{
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"id": id,
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"type": msgType,
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"to": types.NewJID(cli.Store.ID.User, types.LegacyUserServer),
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},
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Content: nil,
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})
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if err != nil {
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cli.Log.Warnf("Failed to send acknowledgement for protocol message %s: %v", id, err)
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}
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}
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