Question

I am now trying to set up Netty with a 2 way SSL handshake, where both the client and server present and verify certificates.

This does not appear to be implemented in SslHandler. Has anyone does this? I suppose it would go in the SslHandler.handshake operation and be delegated to javax.net.ssl.SSLEngine?

Any hints/tips/pre-existing implementations?

Thanks!

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ANSWER (stackoverflow won’t let me post it the normal way) I found that if I set the needClientAuth flag on the SSLEngine object before setting up my SslHandler, that takes care of the problem!

Answer 1

Here is the solution, based on the HttpSnoop server example from the netty project.

When setting up the client side pipeline, the ssl engine must be set as follows:

public ChannelPipeline getPipeline() throws Exception {
    // Create a default pipeline implementation.
    ChannelPipeline pipeline = pipeline();

    // Uncomment the following line if you want HTTPS
    SSLEngine engine = SecureChatSslContextFactory.getServerContext().createSSLEngine();
    engine.setUseClientMode(false);
    engine.setNeedClientAuth(true);
    pipeline.addLast("ssl", new SslHandler(engine));

    pipeline.addLast("decoder", new HttpRequestDecoder());
    pipeline.addLast("logger", new RequestAuditLogger());
    // Uncomment the following line if you don't want to handle HttpChunks.
    pipeline.addLast("aggregator", new HttpChunkAggregator(1048576));
    pipeline.addLast("outputLogger", new ResponseAuditLogger());
    pipeline.addLast("encoder", new HttpResponseEncoder());
    // Remove the following line if you don't want automatic content compression.
    pipeline.addLast("deflater", new HttpContentCompressor());
    pipeline.addLast("handler", new HttpSnoopServerHandler());
    return pipeline;
}
}

Then your SSLContext must be modified as follows to set up a trust store in addition to a keystore (SecureChatSslContextFactory):

public final class SecureChatSslContextFactory {


private static Logger logger = LoggerFactory.getLogger(SecureChatSslContextFactory.class);

private static final String PROTOCOL = "TLS";
private static final SSLContext SERVER_CONTEXT;
private static final SSLContext CLIENT_CONTEXT;

static {

    SSLContext serverContext = null;
    SSLContext clientContext = null;

        // get keystore and trustore locations and passwords
    String keyStoreLocation = System.getProperty("javax.net.ssl.keyStore");
    String keyStorePassword = System.getProperty("javax.net.ssl.keyStorePassword");
    String trustStoreLocation = System.getProperty("javax.net.ssl.trustStore");
    String trustStorePassword = System.getProperty("javax.net.ssl.trustStorePassword");
    try {

        KeyStore ks = KeyStore.getInstance("JKS");
        ks.load(KeyStoreStreamManager.asInputStream(keyStoreLocation),
                keyStorePassword.toCharArray());

        // Set up key manager factory to use our key store
        KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        kmf.init(ks, keyStorePassword.toCharArray());

          // truststore
        KeyStore ts = KeyStore.getInstance("JKS");
        ts.load(KeyStoreStreamManager.asInputStream(trustStoreLocation),
                trustStorePassword.toCharArray());

        // set up trust manager factory to use our trust store
        TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ts);

        // Initialize the SSLContext to work with our key managers.
        serverContext = SSLContext.getInstance(PROTOCOL);
        serverContext.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);

    } catch (Exception e) {
        throw new Error(
                "Failed to initialize the server-side SSLContext", e);
    }

    try {
        clientContext = SSLContext.getInstance(PROTOCOL);
        clientContext.init(null, SecureChatTrustManagerFactory.getTrustManagers(), null);
    } catch (Exception e) {
        throw new Error(
                "Failed to initialize the client-side SSLContext", e);
    }

    SERVER_CONTEXT = serverContext;
    CLIENT_CONTEXT = clientContext;
}

public static SSLContext getServerContext() {
    return SERVER_CONTEXT;
}

public static SSLContext getClientContext() {
    return CLIENT_CONTEXT;
}

private SecureChatSslContextFactory() {
    // Unused
}
}