Why does an SSL Server Socket connection block in Java whereas a non SSL Server Socket does not?

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Consider the following code for a non-SSL Socket server and client all on the one thread:

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;



public class ServerClient {

    public static void main(String args) throws IOException {

        ServerSocket ss = new ServerSocket(0); // open a random free port.



        Socket c = new Socket(ss.getInetAddress(), ss.getLocalPort());



        Socket s = ss.accept();



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = c.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(s.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        c.close();

        ss.close();

    }

}

This produces the following output:

writing to stream

reading from stream

Hello World!

This process opened a server socket - connected with a client socket. Passed data down the socket and then closed down. There was no issue passing the data.

Consider a version to a prove a point with SSL Sockets:

import javax.net.ssl.SSLServerSocket;

import javax.net.ssl.SSLServerSocketFactory;

import javax.net.ssl.SSLSocket;

import javax.net.ssl.SSLSocketFactory;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.Socket;

import java.util.logging.Logger;



public class SSLServerClient {



    private static Logger log = Logger.getLogger("InfoLogging");



    public static void main(String args) throws IOException {



        System.setProperty("javax.net.ssl.keyStore", "/path/KeyStore.jks");

        System.setProperty("javax.net.ssl.keyStorePassword", "password");



        SSLServerSocketFactory sslserversocketfactory = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();



        SSLServerSocket serverListeningSSLSocket = (SSLServerSocket) sslserversocketfactory.createServerSocket(4380);

        log.info("Server started");



        SSLSocketFactory sslSocketFactory=(SSLSocketFactory) SSLSocketFactory.getDefault();

        SSLSocket clientSocket =  (SSLSocket) sslSocketFactory.createSocket(serverListeningSSLSocket.getInetAddress(),

                serverListeningSSLSocket.getLocalPort());



        SSLSocket serverCommsSSLSocket = (SSLSocket) serverListeningSSLSocket.accept();

        log.info("new client");



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = clientSocket.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(serverCommsSSLSocket.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        clientSocket.close();

        serverCommsSSLSocket.close();

        serverListeningSSLSocket.close();

    }

}

This gives the following output:

Nov 21, 2018 10:23:51 PM com.gamble.ssl.SSLServerClient main INFO: Server started

Nov 21, 2018 10:23:52 PM com.gamble.ssl.SSLServerClient main INFO: new client

writing to stream

ie it blocks on the server socket starting.

My question is: Why does an SSL Server Socket connection block in Java whereas a non SSL Server Socket does not?

java sockets ssl sslsocketfactory

share|improve this question

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

add a comment | 

up vote
0
down vote

favorite

Consider the following code for a non-SSL Socket server and client all on the one thread:

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;



public class ServerClient {

    public static void main(String args) throws IOException {

        ServerSocket ss = new ServerSocket(0); // open a random free port.



        Socket c = new Socket(ss.getInetAddress(), ss.getLocalPort());



        Socket s = ss.accept();



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = c.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(s.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        c.close();

        ss.close();

    }

}

This produces the following output:

writing to stream

reading from stream

Hello World!

This process opened a server socket - connected with a client socket. Passed data down the socket and then closed down. There was no issue passing the data.

Consider a version to a prove a point with SSL Sockets:

import javax.net.ssl.SSLServerSocket;

import javax.net.ssl.SSLServerSocketFactory;

import javax.net.ssl.SSLSocket;

import javax.net.ssl.SSLSocketFactory;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.Socket;

import java.util.logging.Logger;



public class SSLServerClient {



    private static Logger log = Logger.getLogger("InfoLogging");



    public static void main(String args) throws IOException {



        System.setProperty("javax.net.ssl.keyStore", "/path/KeyStore.jks");

        System.setProperty("javax.net.ssl.keyStorePassword", "password");



        SSLServerSocketFactory sslserversocketfactory = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();



        SSLServerSocket serverListeningSSLSocket = (SSLServerSocket) sslserversocketfactory.createServerSocket(4380);

        log.info("Server started");



        SSLSocketFactory sslSocketFactory=(SSLSocketFactory) SSLSocketFactory.getDefault();

        SSLSocket clientSocket =  (SSLSocket) sslSocketFactory.createSocket(serverListeningSSLSocket.getInetAddress(),

                serverListeningSSLSocket.getLocalPort());



        SSLSocket serverCommsSSLSocket = (SSLSocket) serverListeningSSLSocket.accept();

        log.info("new client");



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = clientSocket.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(serverCommsSSLSocket.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        clientSocket.close();

        serverCommsSSLSocket.close();

        serverListeningSSLSocket.close();

    }

}

This gives the following output:

Nov 21, 2018 10:23:51 PM com.gamble.ssl.SSLServerClient main INFO: Server started

Nov 21, 2018 10:23:52 PM com.gamble.ssl.SSLServerClient main INFO: new client

writing to stream

ie it blocks on the server socket starting.

My question is: Why does an SSL Server Socket connection block in Java whereas a non SSL Server Socket does not?

java sockets ssl sslsocketfactory

share|improve this question

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

add a comment | 

up vote
0
down vote

favorite

up vote
0
down vote

favorite

Consider the following code for a non-SSL Socket server and client all on the one thread:

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;



public class ServerClient {

    public static void main(String args) throws IOException {

        ServerSocket ss = new ServerSocket(0); // open a random free port.



        Socket c = new Socket(ss.getInetAddress(), ss.getLocalPort());



        Socket s = ss.accept();



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = c.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(s.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        c.close();

        ss.close();

    }

}

This produces the following output:

writing to stream

reading from stream

Hello World!

This process opened a server socket - connected with a client socket. Passed data down the socket and then closed down. There was no issue passing the data.

Consider a version to a prove a point with SSL Sockets:

import javax.net.ssl.SSLServerSocket;

import javax.net.ssl.SSLServerSocketFactory;

import javax.net.ssl.SSLSocket;

import javax.net.ssl.SSLSocketFactory;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.Socket;

import java.util.logging.Logger;



public class SSLServerClient {



    private static Logger log = Logger.getLogger("InfoLogging");



    public static void main(String args) throws IOException {



        System.setProperty("javax.net.ssl.keyStore", "/path/KeyStore.jks");

        System.setProperty("javax.net.ssl.keyStorePassword", "password");



        SSLServerSocketFactory sslserversocketfactory = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();



        SSLServerSocket serverListeningSSLSocket = (SSLServerSocket) sslserversocketfactory.createServerSocket(4380);

        log.info("Server started");



        SSLSocketFactory sslSocketFactory=(SSLSocketFactory) SSLSocketFactory.getDefault();

        SSLSocket clientSocket =  (SSLSocket) sslSocketFactory.createSocket(serverListeningSSLSocket.getInetAddress(),

                serverListeningSSLSocket.getLocalPort());



        SSLSocket serverCommsSSLSocket = (SSLSocket) serverListeningSSLSocket.accept();

        log.info("new client");



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = clientSocket.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(serverCommsSSLSocket.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        clientSocket.close();

        serverCommsSSLSocket.close();

        serverListeningSSLSocket.close();

    }

}

This gives the following output:

Nov 21, 2018 10:23:51 PM com.gamble.ssl.SSLServerClient main INFO: Server started

Nov 21, 2018 10:23:52 PM com.gamble.ssl.SSLServerClient main INFO: new client

writing to stream

ie it blocks on the server socket starting.

My question is: Why does an SSL Server Socket connection block in Java whereas a non SSL Server Socket does not?

java sockets ssl sslsocketfactory

share|improve this question

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

Consider the following code for a non-SSL Socket server and client all on the one thread:

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;



public class ServerClient {

    public static void main(String args) throws IOException {

        ServerSocket ss = new ServerSocket(0); // open a random free port.



        Socket c = new Socket(ss.getInetAddress(), ss.getLocalPort());



        Socket s = ss.accept();



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = c.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(s.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        c.close();

        ss.close();

    }

}

This produces the following output:

writing to stream

reading from stream

Hello World!

This process opened a server socket - connected with a client socket. Passed data down the socket and then closed down. There was no issue passing the data.

Consider a version to a prove a point with SSL Sockets:

import javax.net.ssl.SSLServerSocket;

import javax.net.ssl.SSLServerSocketFactory;

import javax.net.ssl.SSLSocket;

import javax.net.ssl.SSLSocketFactory;

import java.io.DataInputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.net.Socket;

import java.util.logging.Logger;



public class SSLServerClient {



    private static Logger log = Logger.getLogger("InfoLogging");



    public static void main(String args) throws IOException {



        System.setProperty("javax.net.ssl.keyStore", "/path/KeyStore.jks");

        System.setProperty("javax.net.ssl.keyStorePassword", "password");



        SSLServerSocketFactory sslserversocketfactory = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault();



        SSLServerSocket serverListeningSSLSocket = (SSLServerSocket) sslserversocketfactory.createServerSocket(4380);

        log.info("Server started");



        SSLSocketFactory sslSocketFactory=(SSLSocketFactory) SSLSocketFactory.getDefault();

        SSLSocket clientSocket =  (SSLSocket) sslSocketFactory.createSocket(serverListeningSSLSocket.getInetAddress(),

                serverListeningSSLSocket.getLocalPort());



        SSLSocket serverCommsSSLSocket = (SSLSocket) serverListeningSSLSocket.accept();

        log.info("new client");



        final byte bytes = "Hello World!".getBytes();

        final OutputStream out = clientSocket.getOutputStream();

        System.out.println("writing to stream");

        out.write(bytes.length);

        out.write(bytes);



        System.out.println("reading from stream");



        final DataInputStream in = new DataInputStream(serverCommsSSLSocket.getInputStream());

        int len = in.read();

        final byte b = new byte[len];

        in.readFully(b);

        System.out.println(new String(b));



        clientSocket.close();

        serverCommsSSLSocket.close();

        serverListeningSSLSocket.close();

    }

}

This gives the following output:

Nov 21, 2018 10:23:51 PM com.gamble.ssl.SSLServerClient main INFO: Server started

Nov 21, 2018 10:23:52 PM com.gamble.ssl.SSLServerClient main INFO: new client

writing to stream

ie it blocks on the server socket starting.

My question is: Why does an SSL Server Socket connection block in Java whereas a non SSL Server Socket does not?

java sockets ssl sslsocketfactory

java sockets ssl sslsocketfactory

share|improve this question

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

share|improve this question

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

share|improve this question

share|improve this question

edited 2 hours ago

edited 2 hours ago

edited 2 hours ago

asked 2 days ago

hawkeye

14.3k1798214

asked 2 days ago

hawkeye

14.3k1798214

asked 2 days ago

hawkeye

14.3k1798214

14.3k1798214

add a comment | 

add a comment | 

1 Answer
1

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oldest

votes

up vote
0
down vote

What does "flip to plaintext?" mean?

Here's what you are doing:

• Creating an SSL server socket


• Creating a normal socket connected to the SSL server socket


• Sending some data from the client side


• Reading some data on the server side

Now, the SSL socket expects encrypted data transfer. But the data you are not sending is not encrypted, so it's not valid SSL and it throws an exception - as it says, "Unrecognized SSL message" because you are not sending a valid SSL message, and "plaintext connection?" is a hint about what might be wrong.

You have to use SSL on both sides of the connection, or they can't talk to each other properly.

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks for this comment - it is super helpful. I've updated the question.
  – hawkeye
  2 hours ago
  

  
  
  
  

add a comment | 

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1 Answer
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1 Answer
1

active

oldest

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active

oldest

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active

oldest

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up vote
0
down vote

What does "flip to plaintext?" mean?

Here's what you are doing:

• Creating an SSL server socket


• Creating a normal socket connected to the SSL server socket


• Sending some data from the client side


• Reading some data on the server side

Now, the SSL socket expects encrypted data transfer. But the data you are not sending is not encrypted, so it's not valid SSL and it throws an exception - as it says, "Unrecognized SSL message" because you are not sending a valid SSL message, and "plaintext connection?" is a hint about what might be wrong.

You have to use SSL on both sides of the connection, or they can't talk to each other properly.

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks for this comment - it is super helpful. I've updated the question.
  – hawkeye
  2 hours ago
  

  
  
  
  

add a comment | 

up vote
0
down vote

What does "flip to plaintext?" mean?

Here's what you are doing:

• Creating an SSL server socket


• Creating a normal socket connected to the SSL server socket


• Sending some data from the client side


• Reading some data on the server side

Now, the SSL socket expects encrypted data transfer. But the data you are not sending is not encrypted, so it's not valid SSL and it throws an exception - as it says, "Unrecognized SSL message" because you are not sending a valid SSL message, and "plaintext connection?" is a hint about what might be wrong.

You have to use SSL on both sides of the connection, or they can't talk to each other properly.

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks for this comment - it is super helpful. I've updated the question.
  – hawkeye
  2 hours ago
  

  
  
  
  

add a comment | 

up vote
0
down vote

up vote
0
down vote

What does "flip to plaintext?" mean?

Here's what you are doing:

• Creating an SSL server socket


• Creating a normal socket connected to the SSL server socket


• Sending some data from the client side


• Reading some data on the server side

Now, the SSL socket expects encrypted data transfer. But the data you are not sending is not encrypted, so it's not valid SSL and it throws an exception - as it says, "Unrecognized SSL message" because you are not sending a valid SSL message, and "plaintext connection?" is a hint about what might be wrong.

You have to use SSL on both sides of the connection, or they can't talk to each other properly.

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

What does "flip to plaintext?" mean?

Here's what you are doing:

• Creating an SSL server socket


• Creating a normal socket connected to the SSL server socket


• Sending some data from the client side


• Reading some data on the server side

Now, the SSL socket expects encrypted data transfer. But the data you are not sending is not encrypted, so it's not valid SSL and it throws an exception - as it says, "Unrecognized SSL message" because you are not sending a valid SSL message, and "plaintext connection?" is a hint about what might be wrong.

You have to use SSL on both sides of the connection, or they can't talk to each other properly.

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

share|improve this answer

share|improve this answer

answered 13 hours ago

immibis

33.8k43562

answered 13 hours ago

immibis

33.8k43562

answered 13 hours ago

immibis

33.8k43562

33.8k43562

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks for this comment - it is super helpful. I've updated the question.
  – hawkeye
  2 hours ago
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Thanks for this comment - it is super helpful. I've updated the question.
  – hawkeye
  2 hours ago
  

  
  
  
  

Thanks for this comment - it is super helpful. I've updated the question.
– hawkeye
2 hours ago

Thanks for this comment - it is super helpful. I've updated the question.
– hawkeye
2 hours ago

add a comment | 

 

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