Android 4.1 to 4.4 KitKat - Enable TLS 1.2 for API

Question

In trying to disable TLS 1.0, there are KitKat devices needing access to my API. I have tried overriding the default socket factory without success. I have tried converting to okhttp. Still not working. How do I get Android KitKat to connect to my API?

Answer 1

I had the same issue on pre-lollipop devices. As I'm using Retrofit, here is the solution for OkHttp.

Tls12SocketFactory.java:

public class Tls12SocketFactory extends SSLSocketFactory {
    private static final String[] TLS_V12_ONLY = {"TLSv1.2"};

    final SSLSocketFactory delegate;

    public Tls12SocketFactory(SSLSocketFactory base) {
        this.delegate = base;
    }

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

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

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

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

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

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

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

    private Socket patch(Socket s) {
        if (s instanceof SSLSocket) {
            ((SSLSocket) s).setEnabledProtocols(TLS_V12_ONLY);
        }
        return s;
    }
}

OkHttpUtils.java:

public class OkHttpUtills {

    public static OkHttpClient createHttpClient() {
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        OkHttpClient.Builder client = new OkHttpClient.Builder()
                .followRedirects(true)
                .followSslRedirects(true)
                .addInterceptor(logging)
                .cache(null)
                .connectTimeout(15, TimeUnit.SECONDS)
                .writeTimeout(15, TimeUnit.SECONDS)
                .readTimeout(15, TimeUnit.SECONDS);
        return enableTls12OnPreLollipop(client).build();
    }


    /**
     * Enables TLSv1.2 protocol (which is disabled by default)
     * on pre-Lollipop devices, as well as on Lollipop, because some issues can take place on Samsung devices.
     *
     * @param client OKHtp client builder
     * @return
     */
    private static OkHttpClient.Builder enableTls12OnPreLollipop(OkHttpClient.Builder client) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN && Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP_MR1) {
            try {
                SSLContext sc = SSLContext.getInstance("TLSv1.2");
                sc.init(null, null, null);
                client.sslSocketFactory(new Tls12SocketFactory(sc.getSocketFactory()));

                ConnectionSpec cs = new ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
                        .tlsVersions(TlsVersion.TLS_1_2)
                        .build();

                List<ConnectionSpec> specs = new ArrayList<>();
                specs.add(cs);
                specs.add(ConnectionSpec.COMPATIBLE_TLS);
                specs.add(ConnectionSpec.CLEARTEXT);

                client.connectionSpecs(specs);
            } catch (Exception exc) {
                Log.e("OkHttpTLSCompat", "Error while setting TLS 1.2", exc);
            }
        }
        return client;
    }
}

Hope this could help you.