增加防探测功能,增加流量加密功能

README.md

@@ -1,11 +1,11 @@
 # Shadow-TLS
 ### TLS伪装代理 -- 包装任意TCP连接为真正合法域名的TLS连接
 ## 基本原理
-与服务端连接后,服务端会请求指定合法的HTTPS域名(例如www.apple.com)并转发TLS握手流量(给防火墙/审计设备表演一个真正的TLS握手),与客户端TLS握手成功后后续将转发实际的TCP流量,对审计设备(防火墙/上网行为管理软件/零信任网关)而言你是访问一个合法且是真实证书的HTTPS网站.
+给审计设备表演一个访问指定网站的TLS握手,在后续的加密流量中传输自定义的数据,由于握手的证书是真实的证书,对审计设备(防火墙/上网行为分析/零信任网关)而言本次TCP连接是访问指定网站的HTTPS流量
 
 ## 使用场景
 - 在有域名白名单的情况下需要将流量转发出去
-- 对抗网络审计设备的审查
+- 审计设备会验证TLS证书合法性,自签证书无法通过审计设备的场景
 
 ## 使用方法
 - 服务端示例:
@@ -18,6 +18,17 @@
 ```shell
 ./shadowtls client -l 0.0.0.0:11222 -s 145.142.63.32:443 -d www.apple.com
 ```
+
+## 探测防御
+- 设置参数密码-p 可开启探测防御功能,服务端检测到非被客户端发起的请求后将会作为标准的SNI代理服务器,转发用于伪装源站的所有流量,对主动探测者而言这台服务器是指定网站的官方服务器
+- 若被大量请求可能造成服务器产生大量流量,注意风控
+
+## 流量加密
+- 设置加密密钥参数-k 可启用流量加密,密钥长度必须为16,24或32个字符
+
+## 已知限制
+- 若审计软件会对HTTPS证书进行替换使用审计软件自签的证书,本工具将不再适用
+
 ## 使用Nginx将本服务和其他443端口服务并存
 - 编译带有stream和stream_ssl_preread模块的nginx
 - 参考以下配置
@@ -69,10 +80,6 @@ http {
 
 ```
 
-
-## 安全性特别说明
-- 包装的TCP流量没有加密,因由上层处理,推荐配合gost使用
-
 ## 特别说明
 - 感谢v2ex网友ihciah的思路灵感.
 - 仅供技术研究,请勿用于非法用途.

cmd/client.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"fmt"
 	"github.com/spf13/cobra"
 	"shadowTLS/shadow"
 )
@@ -17,6 +18,10 @@ var (
 		Use:   "client",
 		Short: "Client mode",
 		Run: func(cmd *cobra.Command, args []string) {
+			if !verifyAndParseEncryptionKey() {
+				fmt.Println("[Client] Invalid encryption key length")
+				return
+			}
 			client := shadow.NewClient(clientParams.ListenAddr, clientParams.ServerAddr, clientParams.SNI)
 			client.Start()
 		},

cmd/root.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/spf13/cobra"
 	"os"
+	"shadowTLS/shadow"
 )
 
 var (
@@ -15,6 +16,8 @@ var (
 
 func init() {
 	rootCmd.CompletionOptions.DisableDefaultCmd = true
+	rootCmd.PersistentFlags().StringVarP(&shadow.HandshakePassword, "password", "p", "", "Password for probe resist.Probe resist will be disabled if password is empty.")
+	rootCmd.PersistentFlags().StringVarP(&shadow.Key, "key", "k", "", "Encryption key for AES-CBC.Encryption will be enabled if key is set.Length of key must be 16,24 or 32.")
 }
 
 func Execute() {
@@ -23,3 +26,11 @@ func Execute() {
 		os.Exit(1)
 	}
 }
+
+func verifyAndParseEncryptionKey() bool {
+	if shadow.Key != "" && len(shadow.Key) != 16 && len(shadow.Key) != 24 && len(shadow.Key) != 32 {
+		return false
+	}
+	shadow.EncryptKey = []byte(shadow.Key)
+	return true
+}

cmd/server.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"fmt"
 	"github.com/spf13/cobra"
 	"shadowTLS/shadow"
 )
@@ -17,6 +18,10 @@ var (
 		Use:   "server",
 		Short: "Server mode",
 		Run: func(cmd *cobra.Command, args []string) {
+			if !verifyAndParseEncryptionKey() {
+				fmt.Println("[Server] Invalid encryption key length")
+				return
+			}
 			server := shadow.NewServer(serverParams.ListenAddr, serverParams.TargetAddr, serverParams.FakeAddr)
 			server.Start()
 		},

main.go

@@ -1,8 +1,14 @@
 package main
 
-import "shadowTLS/cmd"
+import (
+	"math/rand"
+	"shadowTLS/cmd"
+	"time"
+)
 
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
 func main() {
-
 	cmd.Execute()
 }

shadow/client.go

@@ -42,11 +42,15 @@ func (c *Client) Start() {
 }
 
 func handlerClient(conn net.Conn, serverAddress string, fakeAddressSNI string) {
+	config := &tls.Config{
+		ServerName: fakeAddressSNI,
+	}
+	if HandshakePassword != "" {
+		config.Rand = RandReaderObj
+	}
 	dial, err := tls.DialWithDialer(&net.Dialer{
 		Timeout: time.Second * 5,
-	}, "tcp", serverAddress, &tls.Config{
-		ServerName: fakeAddressSNI,
-	})
+	}, "tcp", serverAddress, config)
 	if err != nil {
 		fmt.Printf("[Client] Dial server error: %v\n", err)
 		return

shadow/client_test.go

@@ -1,6 +1,8 @@
 package shadow
 
 import (
+	"bytes"
+	"crypto/md5"
 	"crypto/tls"
 	"fmt"
 	"net"
@@ -8,7 +10,7 @@ import (
 	"time"
 )
 
-func TestName(t *testing.T) {
+func TestHandshake(t *testing.T) {
 	dial, err := tls.DialWithDialer(&net.Dialer{
 		Timeout: time.Second * 5,
 	}, "tcp", "evan.run:443", &tls.Config{
@@ -22,15 +24,43 @@ func TestName(t *testing.T) {
 	time.Sleep(time.Minute)
 }
 
-func TestName2(t *testing.T) {
-	b := []byte("ABC")
-	encrypt, err := AesEncrypt(b, []byte("1234567812345678"))
-	if err != nil {
-		fmt.Println(err)
+func TestMd5(t *testing.T) {
+	key := "Passwd"
+	passwd := []byte(key)
+
+	buf := make([]byte, 32)
+	srcCode := md5.Sum(RandomByte(16))
+	copy(buf[0:], srcCode[0:])
+	buffer := bytes.NewBuffer(srcCode[:])
+
+	sum := md5.Sum(passwd)
+	buffer.Write(sum[:])
+
+	hash := md5.Sum(buffer.Bytes())
+	copy(buf[16:], hash[0:])
+	fmt.Println(buf)
+
+	vBuf := make([]byte, 32)
+	copy(vBuf, buf[0:16])
+	verifyBuf := bytes.NewBuffer(vBuf)
+	verifyBuf.Write(sum[:])
+
+	verifyHash := md5.Sum(buffer.Bytes())
+	if bytes.Equal(verifyHash[:], buf[16:32]) {
+		fmt.Println("GOOD")
 	}
-	decrypt, err := AesDecrypt(encrypt, []byte("1234567812345678"))
-	if err != nil {
-		fmt.Println(err)
+	if VerifyKey(buf, key) {
+		fmt.Println("VerifyKey GOOD")
 	}
-	fmt.Println(string(decrypt))
+
+}
+
+func TestAes(t *testing.T) {
+	key := []byte("1234567812345678")
+	data := []byte("AVC")
+
+	e := AesEncryptCBC(data, key)
+	d := AesDecryptCBC(e, key)
+
+	fmt.Println(string(d))
 }

shadow/global.go

@@ -0,0 +1,8 @@
+package shadow
+
+var (
+	HandshakePassword = ""
+	RandReaderObj     = &RandReader{}
+	EncryptKey        = []byte{}
+	Key               = ""
+)

shadow/packer.go

@@ -47,6 +47,12 @@ func (m PackAppData) Read(p []byte) (n int, err error) {
 			copy(p[sum:], buf[HeaderLength+2+sum:HeaderLength+2+sum+r])
 			sum += r
 		}
+		if len(EncryptKey) > 0 {
+			encryptedData := p[0:sum]
+			decrypted := AesDecryptCBC(encryptedData, EncryptKey)
+			copy(p[0:], decrypted)
+			sum = len(decrypted)
+		}
 		return sum, err
 	} else {
 		fmt.Printf("Invalid header")
@@ -55,15 +61,30 @@ func (m PackAppData) Read(p []byte) (n int, err error) {
 }
 
 func (m PackAppData) Write(p []byte) (n int, err error) {
+	var sendData []byte
+	if len(EncryptKey) > 0 {
+		sendData = AesEncryptCBC(p, EncryptKey)
+	} else {
+		sendData = p
+	}
+
 	lenNum := make([]byte, 2)
-	binary.BigEndian.PutUint16(lenNum, uint16(len(p)))
+	binary.BigEndian.PutUint16(lenNum, uint16(len(sendData)))
 
 	packetBuf := bytes.NewBuffer(AppDataHeader)
 	packetBuf.Write(lenNum)
-	packetBuf.Write(p)
+	packetBuf.Write(sendData)
 
 	write, err := m.Conn.Write(packetBuf.Bytes())
-	write = write - HeaderLength - 2
+	if len(EncryptKey) > 0 {
+		if write != packetBuf.Len() {
+			write = 0
+		} else {
+			write = len(p)
+		}
+	} else {
+		write = write - HeaderLength - 2
+	}
 	return write, err
 }
 

shadow/rand.go

@@ -0,0 +1,49 @@
+package shadow
+
+import (
+	"bytes"
+	"crypto/md5"
+	"io"
+	"math/rand"
+)
+
+type RandReader struct {
+	io.Reader
+}
+
+func (r RandReader) Read(p []byte) (n int, err error) {
+	buf := make([]byte, 32)
+	randBytes := md5.Sum(RandomByte(16))
+	copy(buf[0:], randBytes[:])
+
+	preHashData := bytes.NewBuffer(randBytes[:])
+	sum := md5.Sum([]byte(HandshakePassword))
+	preHashData.Write(sum[:])
+	hash := md5.Sum(preHashData.Bytes())
+	copy(buf[16:], hash[:])
+	copy(p, buf)
+	return 32, nil
+}
+
+func RandomByte(size int) []byte {
+	buf := make([]byte, size)
+	for i := 0; i < size; i++ {
+		buf[i] = byte(rand.Intn(255))
+	}
+	return buf
+}
+
+func VerifyKey(p []byte, key string) bool {
+	if len(p) != 32 {
+		return false
+	}
+	buf := make([]byte, 16)
+	copy(buf, p[0:16])
+	buffer := bytes.NewBuffer(buf)
+	sum := md5.Sum([]byte(key))
+	buffer.Write(sum[:])
+
+	hash := md5.Sum(buffer.Bytes())
+
+	return bytes.Equal(hash[:], p[16:])
+}

shadow/server.go

@@ -79,62 +79,11 @@ func handler(conn net.Conn, targetAddress string, fakeAddress string) {
 	go MyCopy(p, realConnection, exit)
 	go MyCopy(realConnection, p, exit)
 	<-exit
-
-	//go func() {
-	//	buf := make([]byte, 64*1024)
-	//	for {
-	//		nr, er := realConnection.Read(buf)
-	//		if er != nil {
-	//			if er == io.EOF {
-	//				continue
-	//			} else {
-	//				fmt.Println("read err:", er)
-	//				break
-	//			}
-	//		} else {
-	//			lenNum := make([]byte, 2)
-	//			binary.BigEndian.PutUint16(lenNum, uint16(nr))
-	//
-	//			packetBuf := bytes.NewBuffer(AppDataHeader)
-	//			packetBuf.Write(lenNum)
-	//			packetBuf.Write(buf[0:nr])
-	//
-	//			_, ew := conn.Write(packetBuf.Bytes())
-	//			if ew != nil {
-	//				fmt.Printf("err2:%v\n", ew)
-	//				break
-	//			}
-	//		}
-	//	}
-	//}()
-	//
-	//go func() {
-	//	result := bytes.NewBuffer(nil)
-	//	var buf [65542]byte // 由于 标识数据包长度 的只有两个字节 故数据包最大为 2^16+4(魔数)+2(长度标识)
-	//	for {
-	//		n, er := conn.Read(buf[0:])
-	//		result.Write(buf[0:n])
-	//		if er != nil {
-	//			if er == io.EOF {
-	//				continue
-	//			} else {
-	//				fmt.Println("read err:", er)
-	//				break
-	//			}
-	//		} else {
-	//			scanner := bufio.NewScanner(result)
-	//			scanner.Split(packetSlitFunc)
-	//			for scanner.Scan() {
-	//				realConnection.Write(scanner.Bytes()[HeaderLength+2:])
-	//			}
-	//		}
-	//		result.Reset()
-	//	}
-	//}()
 }
 
 func processHandshake(src net.Conn, dst net.Conn, waitCh chan int, srcType string) {
 	buf := make([]byte, 32*1024)
+	verifyPass := false
 	for {
 		nr, er := src.Read(buf)
 		if nr > 0 {
@@ -142,10 +91,17 @@ func processHandshake(src net.Conn, dst net.Conn, waitCh chan int, srcType strin
 			if srcType == "client" {
 				header := ParseAndVerifyTLSHeader(buf[0:nr])
 				if header != nil {
+					if header != nil && header.Type == Handshake && header.HandshakeType == ClientHello && !verifyPass {
+						verifyPass = VerifyKey(header.Rand, HandshakePassword)
+					}
 					if header.Type == ChangeCipherSpec {
-						fmt.Println("[Server] handshake complete")
-						waitCh <- 1
-						break
+						if HandshakePassword != "" && !verifyPass {
+							fmt.Println("[Server] Probe detected,pass through all traffic.")
+						} else {
+							fmt.Println("[Server] handshake complete")
+							waitCh <- 1
+							break
+						}
 					}
 					//fmt.Println(header.toString())
 				}

shadow/tls_util.go

@@ -31,6 +31,7 @@ type TLSHeader struct {
 	Length               int
 	HandshakeType        uint8
 	ChangeCipherSpecNext uint8
+	Rand                 []byte
 }
 
 func (t *TLSHeader) toString() string {
@@ -95,6 +96,9 @@ func ParseAndVerifyTLSHeader(data []byte) *TLSHeader {
 		if header.HandshakeType != ServerHello && header.HandshakeType != ClientHello && header.HandshakeType != Certificate && header.HandshakeType != ServerKeyExchange && header.HandshakeType != ServerHelloDone {
 			header.HandshakeType = EncryptedHandshake
 		}
+		if header.HandshakeType == ClientHello {
+			header.Rand = data[11:43]
+		}
 	}
 	if header.Type == ChangeCipherSpec {
 		if len(data) > 6 {