Direct proxy works

wrappers/mtproto_cipher.go

@@ -1,98 +0,0 @@
-package wrappers
-
-import (
-	"bytes"
-	"crypto/aes"
-	"crypto/cipher"
-	"crypto/md5"  // nolint: gas
-	"crypto/sha1" // nolint: gosec
-	"encoding/binary"
-	"net"
-
-	"github.com/9seconds/mtg/mtproto/rpc"
-	"github.com/9seconds/mtg/utils"
-)
-
-type cipherPurpose uint8
-
-const (
-	cipherPurposeClient cipherPurpose = iota
-	cipherPurposeServer
-)
-
-var emptyIP = [4]byte{0x00, 0x00, 0x00, 0x00}
-
-// NewMiddleProxyCipher creates new block cipher to proxy<->telegram
-// connection.
-func NewMiddleProxyCipher(conn StreamReadWriteCloser,
-	req *rpc.NonceRequest, resp *rpc.NonceResponse, secret []byte) StreamReadWriteCloser {
-	localAddr := conn.LocalAddr()
-	remoteAddr := conn.RemoteAddr()
-
-	encKey, encIV := deriveKeys(cipherPurposeClient, req, resp, localAddr, remoteAddr, secret)
-	decKey, decIV := deriveKeys(cipherPurposeServer, req, resp, localAddr, remoteAddr, secret)
-
-	enc, _ := makeEncrypterDecrypter(encKey, encIV)
-	_, dec := makeEncrypterDecrypter(decKey, decIV)
-
-	return NewBlockCipher(conn, enc, dec)
-}
-
-func deriveKeys(purpose cipherPurpose, req *rpc.NonceRequest, resp *rpc.NonceResponse,
-	client, remote *net.TCPAddr, secret []byte) ([]byte, []byte) {
-	message := bytes.Buffer{}
-	message.Write(resp.Nonce)   // nolint: gosec
-	message.Write(req.Nonce)    // nolint: gosec
-	message.Write(req.CryptoTS) // nolint: gosec
-
-	clientIPv4 := emptyIP[:]
-	serverIPv4 := emptyIP[:]
-	if client.IP.To4() != nil {
-		clientIPv4 = utils.ReverseBytes(client.IP.To4())
-		serverIPv4 = utils.ReverseBytes(remote.IP.To4())
-	}
-	message.Write(serverIPv4) // nolint: gosec
-
-	var port [2]byte
-	binary.LittleEndian.PutUint16(port[:], uint16(client.Port))
-	message.Write(port[:]) // nolint: gosec
-
-	switch purpose {
-	case cipherPurposeClient:
-		message.WriteString("CLIENT") // nolint: gosec
-	case cipherPurposeServer:
-		message.WriteString("SERVER") // nolint: gosec
-	default:
-		panic("Unexpected cipher purpose")
-	}
-
-	message.Write(clientIPv4) // nolint: gosec
-	binary.LittleEndian.PutUint16(port[:], uint16(remote.Port))
-	message.Write(port[:])    // nolint: gosec
-	message.Write(secret)     // nolint: gosec
-	message.Write(resp.Nonce) // nolint: gosec
-
-	if client.IP.To4() == nil {
-		message.Write(client.IP.To16()) // nolint: gosec
-		message.Write(remote.IP.To16()) // nolint: gosec
-	}
-	message.Write(req.Nonce) // nolint: gosec
-
-	data := message.Bytes()
-	md5sum := md5.Sum(data[1:]) // nolint: gas
-	sha1sum := sha1.Sum(data)   // nolint: gosec
-
-	key := append(md5sum[:12], sha1sum[:]...)
-	iv := md5.Sum(data[2:]) // nolint: gas
-
-	return key, iv[:]
-}
-
-func makeEncrypterDecrypter(key, iv []byte) (cipher.BlockMode, cipher.BlockMode) {
-	block, err := aes.NewCipher(key)
-	if err != nil {
-		panic(err)
-	}
-
-	return cipher.NewCBCEncrypter(block, iv), cipher.NewCBCDecrypter(block, iv)
-}