Java TLS echo server

README.md

Dummy echo server with TLS in Java.

Usage

git clone https://gist.github.com/ulidtko/f44360b0ac15dd7d42e21de6b964ace5 java-tls-echoserv
cd java-tls-echoserv
javac TlsEchoServer.java
java TlsEchoServer 9011 ./java-pleasure.jks 123456 123456

#-- or, with verbose debug dump of the handshake:
java -Djavax.net.debug=ssl,handshake \
     TlsEchoServer 9011 ./java-pleasure.jks 123456 123456

See elsewhere for how to use keytool to generate or import certificates and keys.

The included java-pleasure.jks contains a dummy self-signed cert for localhost.

java-pleasure.jks

TlsEchoServer.java

import java.io.*;
import java.net.*;
import java.security.*;
import javax.net.ssl.*;

public class TlsEchoServer {

   public static void main(String[] args) {

      if (args.length != 4) {
         System.out.println("Usage: java TlsEchoServer <port> <jks> <jkspass> <certkeypass>");
         return;
         // Prepare a JKS using keytool, containing:
         //  - a cert for the server
         //  - privkey for the cert
         //  - alias should match CN/hostname
         //  - jks format should be PKCS12
         // Dump the handshake using -Djavax.net.debug=ssl,handshake
      }

      int port = Integer.parseInt(args[0]);
      String jkspath = args[1];
      String jkspass = args[2];
      String certpass = args[3];

      try {
         //System.out.println("-- Crypto providers dump --");
         //Provider[] providers = Security.getProviders();
         //for (int i = 0; i < providers.length; ++i) {
         //   System.out.println("  " + providers[i].toString());
         //}

         KeyStore ks = KeyStore.getInstance("PKCS12");
         ks.load(new FileInputStream(jkspath), jkspass.toCharArray());
         KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
         kmf.init(ks, certpass.toCharArray());

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

         System.out.println("SSLContext init'd");
         System.out.println("  provider: " + ctx.getProvider().toString());
         System.out.println("  protocol: " + ctx.getProtocol().toString());

         SSLServerSocketFactory ssf = ctx.getServerSocketFactory();

         SSLServerSocket s
            = (SSLServerSocket) ssf.createServerSocket(port);
         //s.setEnabledCipherSuites(new String[]{"TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256"});
         printServerSocketInfo(s);

         SSLSocket c = null;
         BufferedWriter w = null;
         BufferedReader r = null;

         while (true) {
            try {
               c = (SSLSocket) s.accept();
               printSocketInfo(c);
               w = new BufferedWriter(new OutputStreamWriter(c.getOutputStream()));
               r = new BufferedReader(new InputStreamReader(c.getInputStream()));
               String m;
               while ((m=r.readLine())!= null) {
                  char[] a = m.toCharArray();
                  w.write(a,0,a.length);
                  w.newLine();
                  w.flush();
                  System.out.println("echo'd back: |" + m + "|");
               }
            } catch (SocketException e) {
               System.err.println(e.toString()); continue;
            } catch (SSLException e) {
               System.err.println(e.toString()); continue;
            } finally {
               w.close();
               r.close();
               c.close();
            }
         }
         //s.close();

      } catch (Exception e) {
         System.err.println(e.toString());
      }
   }
   private static void printSocketInfo(SSLSocket s) {
      System.out.println("Socket class: " + s.getClass());
      System.out.println("   Remote address = " + s.getInetAddress().toString());
      System.out.println("   Remote port = " + s.getPort());
      System.out.println("   Local socket address = " + s.getLocalSocketAddress().toString());
      System.out.println("   Local address = " + s.getLocalAddress().toString());
      System.out.println("   Local port = " + s.getLocalPort());
      System.out.println("   Need client authentication = " + s.getNeedClientAuth());
      SSLSession ss = s.getSession();
      System.out.println("   Protocol = " + ss.getProtocol());
      System.out.println("   Cipher suite = " + ss.getCipherSuite());
   }
   private static void printServerSocketInfo(SSLServerSocket s) {
      System.out.println("Server socket class: " + s.getClass());
      System.out.println("   Socket address = " + s.getInetAddress().toString() + ":" + s.getLocalPort());
      System.out.println("   Need client authentication = " + s.getNeedClientAuth());
      System.out.println("   Want client authentication = " + s.getWantClientAuth());
      System.out.println("   Use client mode = " + s.getUseClientMode());
      System.out.println("   Enabled protocols: " + String.join(" ", s.getEnabledProtocols()));
      System.out.println("   Enabled ciphersuites: " + String.join(" ", s.getEnabledCipherSuites()));
   }
}