MINA、Netty、Twisted一塊兒學（十一）：SSL/TLS

時間 2019-12-14

標籤 mina netty twisted 一塊兒十一 ssl tls 欄目 Netty 简体版

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什麼是SSL/TLS

不使用SSL/TLS的網絡通訊，通常都是明文傳輸，網絡傳輸內容在傳輸過程當中很容易被竊聽甚至篡改，很是不安全。SSL/TLS協議就是爲了解決這些安全問題而設計的。SSL/TLS協議位於TCP/IP協議之上，各個應用層協議之下，使網絡傳輸的內容經過加密算法加密，而且只有服務器和客戶端能夠加密解密，中間人即便抓到數據包也沒法解密獲取傳輸的內容，從而避免安全問題。例如普遍使用的HTTPS協議便是在TCP協議和HTTP協議之間加了一層SSL/TLS協議。html

SSL/TLS流程

使用SSL/TLS協議的服務器和客戶端開始通訊以前，會先進行一個握手階段：node

客戶端發出請求：這一步客戶端會生成一個隨機數傳給服務器；
服務器迴應：這一步服務器會返回給客戶端一個服務器數字證書（證書中包含用於加密的公鑰），另外服務器也會生成一個隨機數給客戶端；
客戶端迴應：這一步客戶端首先會校驗數字證書的合法性，而後會再生成一個隨機數，這個隨機數會使用第2步中的公鑰採用非對稱加密算法（例如RSA算法）進行加密後傳給服務器，密文只能經過服務器的私鑰來解密。
服務器最後迴應：握手結束。

握手結束後，客戶端和服務器都有上面握手階段的三個隨機數。客戶端和服務器都經過這三個隨機生成一個密鑰，接下來全部的通訊內容都使用這個密鑰經過對稱加密算法加密傳輸，服務器和客戶端纔開始進行安全的通訊。react

若是看到這裏仍是一臉懵逼，能夠參考SSL/TLS協議運行機制的概述更深刻地瞭解SSL/TLS流程，本文再也不過多介紹。git

生成私鑰和證書

使用openssl來生成私鑰和證書：github

openssl req -x509 -newkey rsa:2048 -nodes -days 365 -keyout private.pem -out cert.crt

運行以上命令後，會在當前目錄下生成一個私鑰文件（private.pem）和一個證書文件（cert.crt）。算法

生成的私鑰和證書Twisted、Netty能夠直接使用，然而MINA對私鑰文件的格式的要求，要將pem格式轉換成der格式，實際上就是將文本文件私鑰轉成二進制文件私鑰。openssl將private.pem轉成private.der私鑰文件：api

openssl pkcs8 -topk8 -inform PEM -in private.pem -outform DER -nocrypt -out private.der

SSL/TLS服務器

接下來在http://xxgblog.com/2014/08/21/mina-netty-twisted-2/一文的基礎上，加上SSL/TLS層。安全

MINA

MINA能夠經過SslFilter來實現SSL/TLS，初始化SslFilter的代碼比較繁瑣：bash

public class MinaServer {

    public static void main(String[] args) throws Exception {


        String certPath = "/Users/wucao/Desktop/ssl/cert.crt";  // 證書
        String privateKeyPath = "/Users/wucao/Desktop/ssl/private.der";  // 私鑰

        // 證書
        // https://docs.oracle.com/javase/7/docs/api/java/security/cert/X509Certificate.html
        InputStream inStream = null;
        Certificate certificate = null;
        try {
            inStream = new FileInputStream(certPath);
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            certificate = cf.generateCertificate(inStream);
        } finally {
            if (inStream != null) {
                inStream.close();
            }
        }

        // 私鑰
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Files.readAllBytes(new File(privateKeyPath).toPath()));
        PrivateKey privateKey = KeyFactory.getInstance("RSA").generatePrivate(keySpec);

        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
        ks.load(null, null);
        Certificate[] certificates = {certificate};
        ks.setKeyEntry("key", privateKey, "".toCharArray(), certificates);

        KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        kmf.init(ks, "".toCharArray());

        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(kmf.getKeyManagers(), null, null);

        IoAcceptor acceptor = new NioSocketAcceptor();
        DefaultIoFilterChainBuilder chain = acceptor.getFilterChain();
        chain.addLast("ssl", new SslFilter(sslContext));  // SslFilter須要放在最前面
        chain.addLast("codec", new ProtocolCodecFilter(new TextLineCodecFactory(Charset.forName("UTF-8"), "\r\n", "\r\n")));
        acceptor.setHandler(new TcpServerHandle());
        acceptor.bind(new InetSocketAddress(8080));
    }
}


class TcpServerHandle extends IoHandlerAdapter {

    @Override
    public void exceptionCaught(IoSession session, Throwable cause)
            throws Exception {
        cause.printStackTrace();
    }

    @Override
    public void messageReceived(IoSession session, Object message)
            throws Exception {
        String line = (String) message;
        System.out.println("messageReceived:" + line);
    }

    @Override
    public void sessionCreated(IoSession session) throws Exception {
        System.out.println("sessionCreated");
    }

    @Override
    public void sessionClosed(IoSession session) throws Exception {
        System.out.println("sessionClosed");
    }
}

Netty

Netty經過添加一個SslHandler來實現SSL/TLS，相對MINA來講代碼就比較簡潔：

public class NettyServer {

    public static void main(String[] args) throws InterruptedException, SSLException {

        File certificate = new File("/Users/wucao/Desktop/ssl/cert.crt");  // 證書
        File privateKey = new File("/Users/wucao/Desktop/ssl/private.pem");  // 私鑰
        final SslContext sslContext = SslContextBuilder.forServer(certificate, privateKey).build();

        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch)
                                throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();

                            // SslHandler要放在最前面
                            SslHandler sslHandler = sslContext.newHandler(ch.alloc());
                            pipeline.addLast(sslHandler);

                            pipeline.addLast(new LineBasedFrameDecoder(80));
                            pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));

                            pipeline.addLast(new TcpServerHandler());
                        }
                    });
            ChannelFuture f = b.bind(8080).sync();
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }

}

class TcpServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        String line = (String) msg;
        System.out.println("channelRead:" + line);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        System.out.println("channelActive");
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {
        System.out.println("channelInactive");
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}

Twisted

Twisted實現SSL/TLS也是很是簡單的，將reactor.listenTCP替換爲reactor.listenSSL便可

# -*- coding:utf-8 –*-

from twisted.protocols.basic import LineOnlyReceiver
from twisted.internet.protocol import Factory
from twisted.internet import reactor, ssl

sslContext = ssl.DefaultOpenSSLContextFactory(
    '/Users/wucao/Desktop/ssl/private.pem',  # 私鑰
    '/Users/wucao/Desktop/ssl/cert.crt',  # 公鑰
)

class TcpServerHandle(LineOnlyReceiver):

    def connectionMade(self):
        print 'connectionMade'

    def connectionLost(self, reason):
        print 'connectionLost'

    def lineReceived(self, data):
        print 'lineReceived:' + data

factory = Factory()
factory.protocol = TcpServerHandle
reactor.listenSSL(8080, factory, sslContext)
reactor.run()

SSL/TLS客戶端

這裏仍是使用Java來寫一個SSL/TLS客戶端，用來測試以上三個服務器程序。須要注意的是，在上面SSL/TLS流程的介紹中，SSL/TLS握手階段的第2步服務器會將證書傳給客戶端，第3步客戶端會校驗證書的合法性，因此下面的代碼首先會讓客戶端信任openssl生成的證書，才能正確的完成SSL/TLS握手。

public class SSLClient {

    public static void main(String args[]) throws Exception {

        // 客戶端信任改證書，將用於校驗服務器傳過來的證書的合法性
        String certPath = "/Users/wucao/Desktop/ssl/cert.crt";
        InputStream inStream = null;
        Certificate certificate = null;
        try {
            inStream = new FileInputStream(certPath);
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            certificate = cf.generateCertificate(inStream);
        } finally {
            if (inStream != null) {
                inStream.close();
            }
        }

        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
        ks.load(null, null);
        ks.setCertificateEntry("cert", certificate);

        TrustManagerFactory tmf = TrustManagerFactory.getInstance("sunx509");
        tmf.init(ks);

        SSLContext sslContext = SSLContext.getInstance("TLS");
        sslContext.init(null, tmf.getTrustManagers(), null);

        SSLSocketFactory socketFactory = sslContext.getSocketFactory();

        Socket socket = null;
        OutputStream out = null;

        try {

            socket = socketFactory.createSocket("localhost", 8080);
            out = socket.getOutputStream();

            // 請求服務器
            String lines = "牀前明月光\r\n疑是地上霜\r\n舉頭望明月\r\n低頭思故鄉\r\n";
            byte[] outputBytes = lines.getBytes("UTF-8");
            out.write(outputBytes);
            out.flush();

        } finally {
            // 關閉鏈接
            out.close();
            socket.close();
        }

    }
}