matterbridge/vendor/go.mau.fi/whatsmeow/msgsecret.go
Wim c4157a4d5b
Update dependencies (#2180)
* Update dependencies

* Fix whatsmeow API changes
2024-08-27 19:04:05 +02:00

283 lines
10 KiB
Go

// Copyright (c) 2022 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package whatsmeow
import (
"crypto/sha256"
"fmt"
"time"
"go.mau.fi/whatsmeow/proto/waCommon"
"go.mau.fi/whatsmeow/proto/waE2E"
"go.mau.fi/util/random"
"google.golang.org/protobuf/proto"
waProto "go.mau.fi/whatsmeow/binary/proto"
"go.mau.fi/whatsmeow/types"
"go.mau.fi/whatsmeow/types/events"
"go.mau.fi/whatsmeow/util/gcmutil"
"go.mau.fi/whatsmeow/util/hkdfutil"
)
type MsgSecretType string
const (
EncSecretPollVote MsgSecretType = "Poll Vote"
EncSecretReaction MsgSecretType = "Enc Reaction"
EncSecretBotMsg MsgSecretType = "Bot Message"
)
func applyBotMessageHKDF(messageSecret []byte) []byte {
return hkdfutil.SHA256(messageSecret, nil, []byte(EncSecretBotMsg), 32)
}
func generateMsgSecretKey(
modificationType MsgSecretType, modificationSender types.JID,
origMsgID types.MessageID, origMsgSender types.JID, origMsgSecret []byte,
) ([]byte, []byte) {
origMsgSenderStr := origMsgSender.ToNonAD().String()
modificationSenderStr := modificationSender.ToNonAD().String()
useCaseSecret := make([]byte, 0, len(origMsgID)+len(origMsgSenderStr)+len(modificationSenderStr)+len(modificationType))
useCaseSecret = append(useCaseSecret, origMsgID...)
useCaseSecret = append(useCaseSecret, origMsgSenderStr...)
useCaseSecret = append(useCaseSecret, modificationSenderStr...)
useCaseSecret = append(useCaseSecret, modificationType...)
secretKey := hkdfutil.SHA256(origMsgSecret, nil, useCaseSecret, 32)
additionalData := []byte(fmt.Sprintf("%s\x00%s", origMsgID, modificationSenderStr))
return secretKey, additionalData
}
func getOrigSenderFromKey(msg *events.Message, key *waCommon.MessageKey) (types.JID, error) {
if key.GetFromMe() {
// fromMe always means the poll and vote were sent by the same user
return msg.Info.Sender, nil
} else if msg.Info.Chat.Server == types.DefaultUserServer {
sender, err := types.ParseJID(key.GetRemoteJid())
if err != nil {
return types.EmptyJID, fmt.Errorf("failed to parse JID %q of original message sender: %w", key.GetRemoteJid(), err)
}
return sender, nil
} else {
sender, err := types.ParseJID(key.GetParticipant())
if sender.Server != types.DefaultUserServer {
err = fmt.Errorf("unexpected server")
}
if err != nil {
return types.EmptyJID, fmt.Errorf("failed to parse JID %q of original message sender: %w", key.GetParticipant(), err)
}
return sender, nil
}
}
type messageEncryptedSecret interface {
GetEncIV() []byte
GetEncPayload() []byte
}
func (cli *Client) decryptMsgSecret(msg *events.Message, useCase MsgSecretType, encrypted messageEncryptedSecret, origMsgKey *waCommon.MessageKey) ([]byte, error) {
pollSender, err := getOrigSenderFromKey(msg, origMsgKey)
if err != nil {
return nil, err
}
baseEncKey, err := cli.Store.MsgSecrets.GetMessageSecret(msg.Info.Chat, pollSender, origMsgKey.GetID())
if err != nil {
return nil, fmt.Errorf("failed to get original message secret key: %w", err)
} else if baseEncKey == nil {
return nil, ErrOriginalMessageSecretNotFound
}
secretKey, additionalData := generateMsgSecretKey(useCase, msg.Info.Sender, origMsgKey.GetID(), pollSender, baseEncKey)
plaintext, err := gcmutil.Decrypt(secretKey, encrypted.GetEncIV(), encrypted.GetEncPayload(), additionalData)
if err != nil {
return nil, fmt.Errorf("failed to decrypt secret message: %w", err)
}
return plaintext, nil
}
func (cli *Client) encryptMsgSecret(chat, origSender types.JID, origMsgID types.MessageID, useCase MsgSecretType, plaintext []byte) (ciphertext, iv []byte, err error) {
ownID := cli.getOwnID()
if ownID.IsEmpty() {
return nil, nil, ErrNotLoggedIn
}
baseEncKey, err := cli.Store.MsgSecrets.GetMessageSecret(chat, origSender, origMsgID)
if err != nil {
return nil, nil, fmt.Errorf("failed to get original message secret key: %w", err)
} else if baseEncKey == nil {
return nil, nil, ErrOriginalMessageSecretNotFound
}
secretKey, additionalData := generateMsgSecretKey(useCase, ownID, origMsgID, origSender, baseEncKey)
iv = random.Bytes(12)
ciphertext, err = gcmutil.Encrypt(secretKey, iv, plaintext, additionalData)
if err != nil {
return nil, nil, fmt.Errorf("failed to encrypt secret message: %w", err)
}
return ciphertext, iv, nil
}
func (cli *Client) decryptBotMessage(messageSecret []byte, msMsg messageEncryptedSecret, messageID types.MessageID, targetSenderJID types.JID, info *types.MessageInfo) ([]byte, error) {
// gcm decrypt key generation
newKey, additionalData := generateMsgSecretKey("", info.Sender, messageID, targetSenderJID, applyBotMessageHKDF(messageSecret))
plaintext, err := gcmutil.Decrypt(newKey, msMsg.GetEncIV(), msMsg.GetEncPayload(), additionalData)
if err != nil {
return nil, fmt.Errorf("failed to decrypt secret message: %w", err)
}
return plaintext, nil
}
// DecryptReaction decrypts a reaction update message. This form of reactions hasn't been rolled out yet,
// so this function is likely not of much use.
//
// if evt.Message.GetEncReactionMessage() != nil {
// reaction, err := cli.DecryptReaction(evt)
// if err != nil {
// fmt.Println(":(", err)
// return
// }
// fmt.Printf("Reaction message: %+v\n", reaction)
// }
func (cli *Client) DecryptReaction(reaction *events.Message) (*waE2E.ReactionMessage, error) {
encReaction := reaction.Message.GetEncReactionMessage()
if encReaction == nil {
return nil, ErrNotEncryptedReactionMessage
}
plaintext, err := cli.decryptMsgSecret(reaction, EncSecretReaction, encReaction, encReaction.GetTargetMessageKey())
if err != nil {
return nil, fmt.Errorf("failed to decrypt reaction: %w", err)
}
var msg waE2E.ReactionMessage
err = proto.Unmarshal(plaintext, &msg)
if err != nil {
return nil, fmt.Errorf("failed to decode reaction protobuf: %w", err)
}
return &msg, nil
}
// DecryptPollVote decrypts a poll update message. The vote itself includes SHA-256 hashes of the selected options.
//
// if evt.Message.GetPollUpdateMessage() != nil {
// pollVote, err := cli.DecryptPollVote(evt)
// if err != nil {
// fmt.Println(":(", err)
// return
// }
// fmt.Println("Selected hashes:")
// for _, hash := range pollVote.GetSelectedOptions() {
// fmt.Printf("- %X\n", hash)
// }
// }
func (cli *Client) DecryptPollVote(vote *events.Message) (*waE2E.PollVoteMessage, error) {
pollUpdate := vote.Message.GetPollUpdateMessage()
if pollUpdate == nil {
return nil, ErrNotPollUpdateMessage
}
plaintext, err := cli.decryptMsgSecret(vote, EncSecretPollVote, pollUpdate.GetVote(), pollUpdate.GetPollCreationMessageKey())
if err != nil {
return nil, fmt.Errorf("failed to decrypt poll vote: %w", err)
}
var msg waE2E.PollVoteMessage
err = proto.Unmarshal(plaintext, &msg)
if err != nil {
return nil, fmt.Errorf("failed to decode poll vote protobuf: %w", err)
}
return &msg, nil
}
func getKeyFromInfo(msgInfo *types.MessageInfo) *waCommon.MessageKey {
creationKey := &waCommon.MessageKey{
RemoteJID: proto.String(msgInfo.Chat.String()),
FromMe: proto.Bool(msgInfo.IsFromMe),
ID: proto.String(msgInfo.ID),
}
if msgInfo.IsGroup {
creationKey.Participant = proto.String(msgInfo.Sender.String())
}
return creationKey
}
// HashPollOptions hashes poll option names using SHA-256 for voting.
// This is used by BuildPollVote to convert selected option names to hashes.
func HashPollOptions(optionNames []string) [][]byte {
optionHashes := make([][]byte, len(optionNames))
for i, option := range optionNames {
optionHash := sha256.Sum256([]byte(option))
optionHashes[i] = optionHash[:]
}
return optionHashes
}
// BuildPollVote builds a poll vote message using the given poll message info and option names.
// The built message can be sent normally using Client.SendMessage.
//
// For example, to vote for the first option after receiving a message event (*events.Message):
//
// if evt.Message.GetPollCreationMessage() != nil {
// pollVoteMsg, err := cli.BuildPollVote(&evt.Info, []string{evt.Message.GetPollCreationMessage().GetOptions()[0].GetOptionName()})
// if err != nil {
// fmt.Println(":(", err)
// return
// }
// resp, err := cli.SendMessage(context.Background(), evt.Info.Chat, pollVoteMsg)
// }
func (cli *Client) BuildPollVote(pollInfo *types.MessageInfo, optionNames []string) (*waProto.Message, error) {
pollUpdate, err := cli.EncryptPollVote(pollInfo, &waProto.PollVoteMessage{
SelectedOptions: HashPollOptions(optionNames),
})
return &waProto.Message{PollUpdateMessage: pollUpdate}, err
}
// BuildPollCreation builds a poll creation message with the given poll name, options and maximum number of selections.
// The built message can be sent normally using Client.SendMessage.
//
// resp, err := cli.SendMessage(context.Background(), chat, cli.BuildPollCreation("meow?", []string{"yes", "no"}, 1))
func (cli *Client) BuildPollCreation(name string, optionNames []string, selectableOptionCount int) *waProto.Message {
msgSecret := random.Bytes(32)
if selectableOptionCount < 0 || selectableOptionCount > len(optionNames) {
selectableOptionCount = 0
}
options := make([]*waProto.PollCreationMessage_Option, len(optionNames))
for i, option := range optionNames {
options[i] = &waProto.PollCreationMessage_Option{OptionName: proto.String(option)}
}
return &waProto.Message{
PollCreationMessage: &waProto.PollCreationMessage{
Name: proto.String(name),
Options: options,
SelectableOptionsCount: proto.Uint32(uint32(selectableOptionCount)),
},
MessageContextInfo: &waProto.MessageContextInfo{
MessageSecret: msgSecret,
},
}
}
// EncryptPollVote encrypts a poll vote message. This is a slightly lower-level function, using BuildPollVote is recommended.
func (cli *Client) EncryptPollVote(pollInfo *types.MessageInfo, vote *waProto.PollVoteMessage) (*waProto.PollUpdateMessage, error) {
plaintext, err := proto.Marshal(vote)
if err != nil {
return nil, fmt.Errorf("failed to marshal poll vote protobuf: %w", err)
}
ciphertext, iv, err := cli.encryptMsgSecret(pollInfo.Chat, pollInfo.Sender, pollInfo.ID, EncSecretPollVote, plaintext)
if err != nil {
return nil, fmt.Errorf("failed to encrypt poll vote: %w", err)
}
return &waProto.PollUpdateMessage{
PollCreationMessageKey: getKeyFromInfo(pollInfo),
Vote: &waProto.PollEncValue{
EncPayload: ciphertext,
EncIV: iv,
},
SenderTimestampMS: proto.Int64(time.Now().UnixMilli()),
}, nil
}