Reverse Tunnel over JSCH (SSH) and HTTPS

Question

I have to implement a reverse tunnel from client to server. I have used JSCH with the following command

session.setPortForwardingR(rport, lhost, lport);

and it works (see also Reverse SSH tunnel with JSCH Java)!

next I have to tunnel my ssh session over an HTTPS stream 2-way authenticated:

client -> firewall -> apache https -> ssh server 

----------------------> HTTPS
====================================> SSH
---------------------->

I'm looking for

1. a small piece of java code to encapsulate SSH into HTTPS
2. 2 way HTTPS authentication
3. APACHE configuration

possible solution:

1) HTTPS Tunnel

1. JHTTPTunnel, but it is based on J2ME and it doesn't support SSL (see also Java Http Tunneling , Is there an Java library for sending binary data over HTTP, HTTP Tunneling?)
2. JOD, but it doesn't support SSL

3) APACHE CONFIGURATION

1. Maybe this configuration works but I have to try

## Load the required modules.
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so

## Listen on port 8443 (in addition to other ports like 80 or 443)
Listen 8443

<VirtualHost *:8443>

  ServerName youwebserver:8443
  DocumentRoot /some/path/maybe/not/required
  ServerAdmin [email protected]

  ## Only ever allow incoming HTTP CONNECT requests.
  ## Explicitly deny other request types like GET, POST, etc.
  ## This tells Apache to return a 403 Forbidden if this virtual
  ## host receives anything other than an HTTP CONNECT.
  RewriteEngine On
  RewriteCond %{REQUEST_METHOD} !^CONNECT [NC]
  RewriteRule ^/(.*)$ - [F,L]

  ## Setup proxying between youwebserver:8443 and yoursshserver:22

  ProxyRequests On
  ProxyBadHeader Ignore
  ProxyVia Full

  ## IMPORTANT: The AllowCONNECT directive specifies a list
  ## of port numbers to which the proxy CONNECT method may
  ## connect.  For security, only allow CONNECT requests
  ## bound for port 22.
  AllowCONNECT 22

  ## IMPORTANT: By default, deny everyone.  If you don't do this
  ## others will be able to connect to port 22 on any host.
  <Proxy *>
    Order deny,allow
    Deny from all
  </Proxy>

  ## Now, only allow CONNECT requests bound for kolich.com
  ## Should be replaced with yoursshserver.com or the hostname
  ## of whatever SSH server you're trying to connect to.  Note
  ## that ProxyMatch takes a regular expression, so you can do
  ## things like (kolich\.com|anothersshserver\.com) if you want
  ## to allow connections to multiple destinations.
  <ProxyMatch (kolich\.com)>
    Order allow,deny
    Allow from all
  </ProxyMatch>

  ## Logging, always a good idea.
  LogLevel warn
  ErrorLog logs/yourwebserver-proxy_error_log
  CustomLog logs/yourwebserver-proxy_request_log combined

</VirtualHost>

Answer 1

The solution proposed by yourself is ok it is based on Implement HTTPS tunneling with JSSE I think.

the basic steps are:

1. define your connection factory for JSCH
2. open a SSL Socket and call "CONNECT " + host + ":" + port

on server side catch all request calling the "CONNECT" and enable 22 SSH port.

But you have also to consider the following issues:

1. tune the timeout because the SSL handshake is quite long
2. enable 2-way authentication or all people can connect to 22 of your server: Using client/server certificates for two way authentication SSL socket on Android

Answer 2

Unfortunatly no any one has tried to reply; I found the solution.

The solution is based on the HTTP 1.1 CONNECT command and doesn't support direct tunnel.

On the Java client

         // Install the all-trusting trust manager
         final SSLContext sc = SSLContext.getInstance("SSL");
         sc.init(null, trustAllCerts, new java.security.SecureRandom());
         JSch jsch = new JSch();
         Session session = jsch.getSession("root", "SSH-server", 22);

         session.setSocketFactory(new SocketFactory() {
          Socket tunnel = null;

          public Socket createSocket(String host, int port) throws IOException, UnknownHostException {

              SSLSocketFactory ssf = sc.getSocketFactory();

              // HTTP
              tunnel = ssf.createSocket(System.getProperty("https.proxyHost"), Integer.getInteger("https.proxyPort"));
              tunnel.setKeepAlive(true);

              doTunnelHandshake(tunnel, host, port);
              System.out.println(tunnel + " connect " + tunnel.isConnected());
              return tunnel; // dummy
          }

          public InputStream getInputStream(Socket socket) throws IOException {
              System.out.println(tunnel + " getInputStream " + socket.isConnected());
              return tunnel.getInputStream();
          }

          public OutputStream getOutputStream(Socket socket) throws IOException {
              System.out.println("getOutputStream");
              return socket.getOutputStream();
          }           });

      session.connect();

      try {
          session.setPortForwardingR(3391, "localhost", 3389);
      ....

where

  private static void doTunnelHandshake(Socket tunnel, String host, int port) throws IOException {
        OutputStream out = tunnel.getOutputStream();
        String msg = "CONNECT " + host + ":" + port + " HTTP/1.0\n" + 
       "User-Agent: " +
       sun.net.www.protocol.http.HttpURLConnection.userAgent + "\r\n\r\n";
        byte b[];
        try {

              b = msg.getBytes("ASCII7");
        } catch (UnsupportedEncodingException ignored) {
              /*
               * If ASCII7 isn't there, something serious is wrong, but Paranoia
               * Is Good (tm)
               */
              b = msg.getBytes();
        }
        out.write(b);
        out.flush();

        /*
         * We need to store the reply so we can create a detailed error message
         * to the user.
         */
        byte reply[] = new byte[200];
        int replyLen = 0;
        int newlinesSeen = 0;
        boolean headerDone = false; /* Done on first newline */

        InputStream in = tunnel.getInputStream();
        boolean error = false;

        while (newlinesSeen < 2) {
              int i = in.read();
              if (i < 0) {
                    throw new IOException("Unexpected EOF from proxy");
              }
              if (i == '\n') {
                    headerDone = true;
                    ++newlinesSeen;
              } else if (i != '\r') {
                    newlinesSeen = 0;
                    if (!headerDone && replyLen < reply.length) {
                          reply[replyLen++] = (byte) i;
                    }
              }
        }

        /*
         * Converting the byte array to a string is slightly wasteful in the
         * case where the connection was successful, but it's insignificant
         * compared to the network overhead.
         */
        String replyStr;
        try {
              replyStr = new String(reply, 0, replyLen, "ASCII7");
        } catch (UnsupportedEncodingException ignored) {
              replyStr = new String(reply, 0, replyLen);
        }

        System.out.println(replyStr);

        /* We asked for HTTP/1.0, so we should get that back */
        if (!replyStr.startsWith("HTTP/1.0 200")) {
              throw new IOException("Unable to tunnel for " + host + ":" + port + ".  Proxy returns \"" + replyStr + "\"");
        }

        /* tunneling Handshake was successful! */
  }

On the apache configuration

add the ssl support

 SSLEngine on
 SSLCertificateFile "conf/ssl.crt/server.crt"
 SSLCertificateKeyFile "conf/ssl.key/server.key"

here the result

Connecting to localhost port 22
HTTP/1.0 200 Connection Established
....
Authentications that can continue: password
Next authentication method: password
Authentication succeeded (password).
Connected