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How to enable TLS 1.2 support in an Android application (running on Android 4.1 JB)

Posted by: admin February 23, 2018 Leave a comment

Questions:

As per the docs in Android for SSLSocket and SSLContext, TLS v1.1 and v1.2 protocols are supported in API level 16+, but are not enabled by default.
http://developer.android.com/reference/javax/net/ssl/SSLSocket.html
http://developer.android.com/reference/javax/net/ssl/SSLContext.html

How do I enable it on a device running Android 4.1 or later (but below 5.0)?

I have tried creating a custom SSLSocketFactory which enables all the supported protocols when Socket‘s are created and later use my custom implementation as:

HttpsURLConnection.setDefaultSSLSocketFactory(new MySSLSocketFactory());

public class MySSLSocketFactory extends SSLSocketFactory {

        private SSLContext sc;
        private SSLSocketFactory ssf;  

        public MySSLSocketFactory() {
            try {
                sc = SSLContext.getInstance("TLS");
                sc.init(null, null, null);
                ssf = sc.getSocketFactory();

            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            } catch (KeyManagementException e) {
                e.printStackTrace();
            }  
        }

        @Override
        public Socket createSocket(Socket s, String host, int port, boolean autoClose)
                throws IOException {
            SSLSocket ss = (SSLSocket) ssf.createSocket(s, host, port, autoClose);
            ss.setEnabledProtocols(ss.getSupportedProtocols());
            ss.setEnabledCipherSuites(ss.getSupportedCipherSuites());
            return ss;
        }

        @Override
        public String[] getDefaultCipherSuites() {
            return ssf.getDefaultCipherSuites();
        }

        @Override
        public String[] getSupportedCipherSuites() {
            return ssf.getSupportedCipherSuites();
        }

        @Override
        public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
            SSLSocket ss = (SSLSocket) ssf.createSocket(host, port);
            ss.setEnabledProtocols(ss.getSupportedProtocols());
            ss.setEnabledCipherSuites(ss.getSupportedCipherSuites());
            return ss;
        }

        @Override
        public Socket createSocket(InetAddress host, int port) throws IOException {
            SSLSocket ss = (SSLSocket) ssf.createSocket(host, port);
            ss.setEnabledProtocols(ss.getSupportedProtocols());
            ss.setEnabledCipherSuites(ss.getSupportedCipherSuites());
            return ss;
        }

        @Override
        public Socket createSocket(String host, int port, InetAddress localHost, int localPort)
                throws IOException, UnknownHostException {
            SSLSocket ss = (SSLSocket) ssf.createSocket(host, port, localHost, localPort);
            ss.setEnabledProtocols(ss.getSupportedProtocols());
            ss.setEnabledCipherSuites(ss.getSupportedCipherSuites());
            return ss;
        }

        @Override
        public Socket createSocket(InetAddress address, int port, InetAddress localAddress,
                int localPort) throws IOException {
            SSLSocket ss = (SSLSocket) ssf.createSocket(address, port, localAddress, localPort);
            ss.setEnabledProtocols(ss.getSupportedProtocols());
            ss.setEnabledCipherSuites(ss.getSupportedCipherSuites());
            return ss;
        }
    }

But it still gives an exception while trying to establish a connection with a server on which Only TLS 1.2 is enabled.

Here is the exception I get:

03-09 09:21:38.427: W/System.err(2496):
javax.net.ssl.SSLHandshakeException:
javax.net.ssl.SSLProtocolException: SSL handshake aborted:
ssl=0xb7fa0620: Failure in SSL library, usually a protocol error

03-09 09:21:38.427: W/System.err(2496): error:14077410:SSL
routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure
(external/openssl/ssl/s23_clnt.c:741 0xa90e6990:0x00000000)

Answers:

2 ways to enable TLSv1.1 and TLSv1.2:

  1. use this guideline:
    http://blog.dev-area.net/2015/08/13/android-4-1-enable-tls-1-1-and-tls-1-2/
  2. use this class
    https://github.com/erickok/transdroid/blob/master/app/src/main/java/org/transdroid/daemon/util/TlsSniSocketFactory.java
    schemeRegistry.register(new Scheme("https", new TlsSniSocketFactory(), port));
Questions:
Answers:

I solved this issue following the indication provided in the article http://blog.dev-area.net/2015/08/13/android-4-1-enable-tls-1-1-and-tls-1-2/ with little changes.

SSLContext context = SSLContext.getInstance("TLS");
context.init(null, null, null);
SSLSocketFactory noSSLv3Factory = null;
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.KITKAT) {
    noSSLv3Factory = new TLSSocketFactory(sslContext.getSocketFactory());
} else {
    noSSLv3Factory = sslContext.getSocketFactory();
}
connection.setSSLSocketFactory(noSSLv3Factory);

This is the code of the custom TLSSocketFactory:

public static class TLSSocketFactory extends SSLSocketFactory {

    private SSLSocketFactory internalSSLSocketFactory;

    public TLSSocketFactory(SSLSocketFactory delegate) throws KeyManagementException, NoSuchAlgorithmException {
        internalSSLSocketFactory = delegate;
    }

    @Override
    public String[] getDefaultCipherSuites() {
        return internalSSLSocketFactory.getDefaultCipherSuites();
    }

    @Override
    public String[] getSupportedCipherSuites() {
        return internalSSLSocketFactory.getSupportedCipherSuites();
    }

    @Override
    public Socket createSocket(Socket s, String host, int port, boolean autoClose) throws IOException {
        return enableTLSOnSocket(internalSSLSocketFactory.createSocket(s, host, port, autoClose));
    }

    @Override
    public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
        return enableTLSOnSocket(internalSSLSocketFactory.createSocket(host, port));
    }

    @Override
    public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException, UnknownHostException {
        return enableTLSOnSocket(internalSSLSocketFactory.createSocket(host, port, localHost, localPort));
    }

    @Override
    public Socket createSocket(InetAddress host, int port) throws IOException {
        return enableTLSOnSocket(internalSSLSocketFactory.createSocket(host, port));
    }

    @Override
    public Socket createSocket(InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
        return enableTLSOnSocket(internalSSLSocketFactory.createSocket(address, port, localAddress, localPort));
    }

    /*
     * Utility methods
     */

    private static Socket enableTLSOnSocket(Socket socket) {
        if (socket != null && (socket instanceof SSLSocket)
                && isTLSServerEnabled((SSLSocket) socket)) { // skip the fix if server doesn't provide there TLS version
            ((SSLSocket) socket).setEnabledProtocols(new String[]{TLS_v1_1, TLS_v1_2});
        }
        return socket;
    }

    private static boolean isTLSServerEnabled(SSLSocket sslSocket) {
        System.out.println("__prova__ :: " + sslSocket.getSupportedProtocols().toString());
        for (String protocol : sslSocket.getSupportedProtocols()) {
            if (protocol.equals(TLS_v1_1) || protocol.equals(TLS_v1_2)) {
                return true;
            }
        }
        return false;
    }
}

Questions:
Answers:

You should use

 SSLContext.getInstance("TLSv1.2"); 

for specific protocol version.

The second exception occured because default socketFactory used fallback SSLv3 protocol for failures.

You can use NoSSLFactory from main answer here for its suppression How to disable SSLv3 in android for HttpsUrlConnection?

Also you should init SSLContext with all your certificates(client and trusted ones if you need them)

But all of that is useless without using

ProviderInstaller.installIfNeeded(getContext())

Here is more information with proper usage scenario https://developer.android.com/training/articles/security-gms-provider.html

Hope it helps.

Questions:
Answers:

I have some additions to above mentioned answers
Its infact a hack mentioned by Jesse Wilson from okhttp, square here. According to this hack, i had to rename my SSLSocketFactory variable to

private SSLSocketFactory delegate;

notice that it would throw error if you give any name other than delegate. Iam posting my complete solution below

This is my TLSSocketFactory class

public class TLSSocketFactory extends SSLSocketFactory {

private SSLSocketFactory delegate;

public TLSSocketFactory() throws KeyManagementException, NoSuchAlgorithmException {
    SSLContext context = SSLContext.getInstance("TLS");
    context.init(null, null, null);
    delegate = context.getSocketFactory();
}

@Override
public String[] getDefaultCipherSuites() {
    return delegate.getDefaultCipherSuites();
}

@Override
public String[] getSupportedCipherSuites() {
    return delegate.getSupportedCipherSuites();
}

@Override
public Socket createSocket() throws IOException {
    return enableTLSOnSocket(delegate.createSocket());
}

@Override
public Socket createSocket(Socket s, String host, int port, boolean autoClose) throws IOException {
    return enableTLSOnSocket(delegate.createSocket(s, host, port, autoClose));
}

@Override
public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
    return enableTLSOnSocket(delegate.createSocket(host, port));
}

@Override
public Socket createSocket(String host, int port, InetAddress localHost, int localPort) throws IOException, UnknownHostException {
    return enableTLSOnSocket(delegate.createSocket(host, port, localHost, localPort));
}

@Override
public Socket createSocket(InetAddress host, int port) throws IOException {
    return enableTLSOnSocket(delegate.createSocket(host, port));
}

@Override
public Socket createSocket(InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
    return enableTLSOnSocket(delegate.createSocket(address, port, localAddress, localPort));
}

private Socket enableTLSOnSocket(Socket socket) {
    if(socket != null && (socket instanceof SSLSocket)) {
        ((SSLSocket)socket).setEnabledProtocols(new String[] {"TLSv1.1", "TLSv1.2"});
    }
    return socket;
}
}

and this is how i used it with okhttp and retrofit

 OkHttpClient client=new OkHttpClient();
    try {
        client = new OkHttpClient.Builder()
                .sslSocketFactory(new TLSSocketFactory())
                .build();
    } catch (KeyManagementException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(URL)
            .client(client)
            .addConverterFactory(GsonConverterFactory.create())
            .build();

Questions:
Answers:

@Inherently Curious – thanks for posting this. You are almost there – you have to add two more params to SSLContext.init() method.

TrustManager[] trustManagers = new TrustManager[] { new TrustManagerManipulator() };
sc.init(null, trustManagers, new SecureRandom());

it will start working. Again thank you very much for posting this. I solved this/my issue with your code.