1 files changed, 135 insertions, 0 deletions
diff --git a/vendor/go.mau.fi/whatsmeow/socket/noisehandshake.go b/vendor/go.mau.fi/whatsmeow/socket/noisehandshake.go
new file mode 100644
index 00000000..26f7f263
--- /dev/null
+++ b/vendor/go.mau.fi/whatsmeow/socket/noisehandshake.go
@@ -0,0 +1,135 @@
+// Copyright (c) 2021 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 socket
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/sha256"
+	"fmt"
+	"io"
+	"sync/atomic"
+
+	"golang.org/x/crypto/curve25519"
+	"golang.org/x/crypto/hkdf"
+)
+
+type NoiseHandshake struct {
+	hash    []byte
+	salt    []byte
+	key     cipher.AEAD
+	counter uint32
+}
+
+func NewNoiseHandshake() *NoiseHandshake {
+	return &NoiseHandshake{}
+}
+
+func newCipher(key []byte) (cipher.AEAD, error) {
+	aesCipher, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	aesGCM, err := cipher.NewGCM(aesCipher)
+	if err != nil {
+		return nil, err
+	}
+	return aesGCM, nil
+}
+
+func sha256Slice(data []byte) []byte {
+	hash := sha256.Sum256(data)
+	return hash[:]
+}
+
+func (nh *NoiseHandshake) Start(pattern string, header []byte) {
+	data := []byte(pattern)
+	if len(data) == 32 {
+		nh.hash = data
+	} else {
+		nh.hash = sha256Slice(data)
+	}
+	nh.salt = nh.hash
+	var err error
+	nh.key, err = newCipher(nh.hash)
+	if err != nil {
+		panic(err)
+	}
+	nh.Authenticate(header)
+}
+
+func (nh *NoiseHandshake) Authenticate(data []byte) {
+	nh.hash = sha256Slice(append(nh.hash, data...))
+}
+
+func (nh *NoiseHandshake) postIncrementCounter() uint32 {
+	count := atomic.AddUint32(&nh.counter, 1)
+	return count - 1
+}
+
+func (nh *NoiseHandshake) Encrypt(plaintext []byte) []byte {
+	ciphertext := nh.key.Seal(nil, generateIV(nh.postIncrementCounter()), plaintext, nh.hash)
+	nh.Authenticate(ciphertext)
+	return ciphertext
+}
+
+func (nh *NoiseHandshake) Decrypt(ciphertext []byte) (plaintext []byte, err error) {
+	plaintext, err = nh.key.Open(nil, generateIV(nh.postIncrementCounter()), ciphertext, nh.hash)
+	if err == nil {
+		nh.Authenticate(ciphertext)
+	}
+	return
+}
+
+func (nh *NoiseHandshake) Finish(fs *FrameSocket, frameHandler FrameHandler, disconnectHandler DisconnectHandler) (*NoiseSocket, error) {
+	if write, read, err := nh.extractAndExpand(nh.salt, nil); err != nil {
+		return nil, fmt.Errorf("failed to extract final keys: %w", err)
+	} else if writeKey, err := newCipher(write); err != nil {
+		return nil, fmt.Errorf("failed to create final write cipher: %w", err)
+	} else if readKey, err := newCipher(read); err != nil {
+		return nil, fmt.Errorf("failed to create final read cipher: %w", err)
+	} else if ns, err := newNoiseSocket(fs, writeKey, readKey, frameHandler, disconnectHandler); err != nil {
+		return nil, fmt.Errorf("failed to create noise socket: %w", err)
+	} else {
+		return ns, nil
+	}
+}
+
+func (nh *NoiseHandshake) MixSharedSecretIntoKey(priv, pub [32]byte) error {
+	secret, err := curve25519.X25519(priv[:], pub[:])
+	if err != nil {
+		return fmt.Errorf("failed to do x25519 scalar multiplication: %w", err)
+	}
+	return nh.MixIntoKey(secret)
+}
+
+func (nh *NoiseHandshake) MixIntoKey(data []byte) error {
+	nh.counter = 0
+	write, read, err := nh.extractAndExpand(nh.salt, data)
+	if err != nil {
+		return fmt.Errorf("failed to extract keys for mixing: %w", err)
+	}
+	nh.salt = write
+	nh.key, err = newCipher(read)
+	if err != nil {
+		return fmt.Errorf("failed to create new cipher while mixing keys: %w", err)
+	}
+	return nil
+}
+
+func (nh *NoiseHandshake) extractAndExpand(salt, data []byte) (write []byte, read []byte, err error) {
+	h := hkdf.New(sha256.New, data, salt, nil)
+	write = make([]byte, 32)
+	read = make([]byte, 32)
+
+	if _, err = io.ReadFull(h, write); err != nil {
+		err = fmt.Errorf("failed to read write key: %w", err)
+	} else if _, err = io.ReadFull(h, read); err != nil {
+		err = fmt.Errorf("failed to read read key: %w", err)
+	}
+	return
+}