On Mon, 2015-09-07 at 11:06 -0700, Ken Krugler wrote:
> Hi there,
> 
> Some background first…
> 
> I was using a fairly old version of HttpClient (4.2.5) to access some 
> Wikipedia pages, and started getting SSLPeerUnverifiedException errors while 
> connecting.
> 
> One change was that Wikipedia recently started only supporting https 
> connections - see 
> http://venturebeat.com/2015/06/12/wikipedia-to-start-using-secure-https-by-default-for-all-users/
> 
> But getting details on what was going wrong was challenging - enabling HTTP 
> wire logging didn't show me much useful information.
> 
> Once I enabled SSL Handshake debug via the Java VM parameter 
> -Djavax.net.debug=ssl:handshake, I could see that the error was "Could not 
> generate DH keypair"
> 
> I then followed the second suggestion at 
> http://stackoverflow.com/questions/10687200/java-7-and-could-not-generate-dh-keypair,
>  which involves getting rid of ciphers that cause problems with Java 7.
> 
> Here's my modified SSLSocketFactory (and yes, for 4.3 or later I should be 
> using SSLConnectionSocketFactory)...
> 
>     private static class MySSLSocketFactory extends SSLSocketFactory {
> 
>         public MySSLSocketFactory(SSLContext sslContext) {
>             super(sslContext);
>         }
>         
>         @Override
>         protected void prepareSocket(SSLSocket socket) throws IOException {
>             super.prepareSocket(socket);
> 
>             String[] enabledCipherSuites = socket.getEnabledCipherSuites();
> 
>             // avoid hardcoding a new list, we just remove the entries
>             // which cause the exception
>             List<String> asList = new 
> ArrayList<String>(Arrays.asList(enabledCipherSuites));
> 
>             // See 
> http://stackoverflow.com/questions/10687200/java-7-and-could-not-generate-dh-keypair
>             // we identified the following entries causing the problems
>             // "Could not generate DH keypair"
>             // and "Caused by: 
> java.security.InvalidAlgorithmParameterException: Prime size must be multiple 
> of 64, and can only range from 512 to 1024 (inclusive)"
>             asList.remove("TLS_DHE_RSA_WITH_AES_128_CBC_SHA");
>             asList.remove("SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA");
>             asList.remove("TLS_DHE_RSA_WITH_AES_256_CBC_SHA");
> 
>             socket.setEnabledCipherSuites(asList.toArray(new 
> String[asList.size()]));
>         }
>     }
> 
> This seems to be working fine, but it feels like a hack to remove specific 
> ciphers.
> 
> Is there a better (more robust) solution? Should this only be used if an 
> un-hacked try fails with this kind of problem?
> 
> Thanks,
> 
> -- Ken

Hi Ken

I see nothing hacky about this solution. Restricting ciphers enabled for
a particular SSL session looks like a normal thing to do.

Oleg


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