【C#】Socket中的ssl通信

引言 
   有个项目中用到了Socket ssl通信,在此记录一下.

证书

Socket ssl需要用到证书用来校验身份,而作为调试,我们只需用测试证书即可.

有个工具可以很方便地制作测试证书,下载地址为http://supersocket.codeplex.com/releases/view/59311

首先, 输入Common Name,密码和保存路径后,我们可以得到包含私钥的证书server.pfx.

然后,安装证书到电脑中,在IE选项中导出一份证书作为client.cer.

客户端

使用客户端的电脑需要安装client.cer到<受信任的根证书颁发机构>,且要把证书放在程序目录中,具体代码如下

 class Program
    {
        private static SslStream _sslStream;

        static void Main(string[] args)
        {

            try
            {
                TcpClient client = new TcpClient("127.0.0.1", 6000);
                Console.WriteLine("Client connected.");
                _sslStream = new SslStream(
                   client.GetStream(),
                   false,
                   new RemoteCertificateValidationCallback(ValidateServerCertificate),
                   null
                   );

                X509CertificateCollection certs = new X509CertificateCollection();
                X509Certificate cert = X509Certificate.CreateFromCertFile(System.Environment.CurrentDirectory + @"\" + "client.cer");
                certs.Add(cert);
                //验证证书
                try
                {
                    _sslStream.AuthenticateAsClient("test", certs, SslProtocols.Tls, false);
                }
                catch (AuthenticationException e)
                {
                    Console.WriteLine("Exception: {0}", e.Message);
                    if (e.InnerException != null)
                    {
                        Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
                    }
                    Console.WriteLine("Authentication failed - closing the connection.");
                    client.Close();
                    Console.ReadLine();
                    return;
                }

                //开始读取消息
                Task.Factory.StartNew(() =>
                {
                    ReadMessage(_sslStream);
                });

                Console.WriteLine("按Q退出程序");
                string message = "";
                message = Console.ReadLine() + "<EOF>";
                while (message != "Q")
                {
                    byte[] bytes = Encoding.UTF8.GetBytes(message);
                    _sslStream.Write(bytes);
                    _sslStream.Flush();
                    Console.WriteLine("send:" + message);
                    message = Console.ReadLine() + "<EOF>";
                }

                client.Close();
            }
            catch (Exception ex)
            {

                Console.WriteLine(ex);
                Console.ReadLine();
            }
        }

        public static void ReadMessage(SslStream sslStream)
        {
            byte[] buffer = new byte[2048];
            StringBuilder messageData = new StringBuilder();
            int bytes = -1;
            do
            {
                bytes = sslStream.Read(buffer, 0, buffer.Length);
                Decoder decoder = Encoding.UTF8.GetDecoder();
                char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                if (messageData.ToString().IndexOf("<EOF>", StringComparison.Ordinal) != -1)
                {
                    break;
                }
            } while (bytes != 0);

            string message = messageData.ToString().Replace("<EOF>", "");
            Console.WriteLine("recevied:" + message);
            ReadMessage(sslStream);
        }

        private static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslpolicyerrors)
        {
            if (sslpolicyerrors == SslPolicyErrors.None)
                return true;
            Console.WriteLine("Certificate error: {0}", sslpolicyerrors);
            return false;
        }
    }

服务端

服务端电脑要安装server.pfx证书,且要把证书放在程序目录中,具体代码如下

  class Program
    {
        static void Main(string[] args)
        {
            TcpListener listener = new TcpListener(IPAddress.Any, 6000);
            listener.Start();

            Console.WriteLine("Waiting for a client to connect...");
            TcpClient client = listener.AcceptTcpClient();

            _sslStream = new SslStream(client.GetStream(), true);

            try
            {
                serverCertificate = new X509Certificate(Environment.CurrentDirectory + @"\" + "server.pfx", "1");
                _sslStream.AuthenticateAsServer(serverCertificate, false, SslProtocols.Tls, true);
            }
            catch (Exception ex)
            {
                 Console.WriteLine(ex);
                 Console.ReadLine();
                 return;
            }

            while (true)
            {
                string receivedMessage = ReadMessage(_sslStream);
                Console.WriteLine("received:" + receivedMessage);
                byte[] message = Encoding.UTF8.GetBytes("Success.<EOF>");
                _sslStream.Write(message);
                _sslStream.Flush();
            }
        }

        static X509Certificate serverCertificate = null;
        private static SslStream _sslStream;

        static string ReadMessage(SslStream sslStream)
        {
            byte[] buffer = new byte[2048];
            StringBuilder messageData = new StringBuilder();
            int bytes = -1;
            do
            {
                bytes = sslStream.Read(buffer, 0, buffer.Length);
                Decoder decoder = Encoding.UTF8.GetDecoder();
                char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                if (messageData.ToString().IndexOf("<EOF>") != -1)
                {
                    break;
                }
            } while (bytes != 0);

            return messageData.ToString();
        }

        static void ProcessClient(TcpClient client)
        {

            SslStream sslStream = new SslStream(
                client.GetStream(), true);

            try
            {
                sslStream.AuthenticateAsServer(serverCertificate, true, SslProtocols.Tls, true);

                Console.WriteLine("Waiting for client message...");
                string messageData = ReadMessage(sslStream);
                Console.WriteLine("Received: {0}", messageData);

                byte[] message = Encoding.UTF8.GetBytes("已收到信息.<EOF>");
                sslStream.Write(message);
                sslStream.Flush();
            }
            catch (AuthenticationException e)
            {
                Console.WriteLine("Exception: {0}", e.Message);
                if (e.InnerException != null)
                {
                    Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
                }
                Console.WriteLine("Authentication failed - closing the connection.");
                sslStream.Close();
                client.Close();
                return;
            }
            finally
            {
                sslStream.Close();
                client.Close();
            }
        }

    }

注意事项

  1.服务端验证方法AuthenticateAsServer的参数clientCertificateRequired如果为true,那在客户端也要安装server.pfx.

2.客户端验证方法AuthenticateAsClient的参数targetHost对应证书中Common Name,也就是受颁发者.

参考资料

   https://msdn.microsoft.com/zh-cn/library/system.net.security.sslstream(v=vs.110).aspx