retrofit2 - Android pre-lollipop devices giving error "SSL handshake aborted: ssl=0x618d9c18: I/O error during system call, Connection reset by peer"

Question

Iam having this strange issue in which the retrofit keeps throwing me

"SSL handshake aborted: ssl=0x618d9c18: I/O error during system call, Connection reset by peer"

in kitkat, whereas the same code working fine in lollipop devices. Iam using an OkHttpClient client like the following

public OkHttpClient getUnsafeOkHttpClient() {
    try {
        final TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
            @Override
            public void checkClientTrusted(
                    java.security.cert.X509Certificate[] chain,
                    String authType) {
            }
            @Override
            public void checkServerTrusted(
                    java.security.cert.X509Certificate[] chain,
                    String authType) {
            }
            @Override
            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return new java.security.cert.X509Certificate[0];
            }
        } };

        int cacheSize = 10 * 1024 * 1024; // 10 MB
        Cache cache = new Cache(getCacheDir(), cacheSize);
        final SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
        sslContext.init(null, trustAllCerts,
                new java.security.SecureRandom());
        final SSLSocketFactory sslSocketFactory = sslContext
                .getSocketFactory();
        OkHttpClient okHttpClient = new OkHttpClient();
        okHttpClient = okHttpClient.newBuilder()
                .cache(cache)
                .sslSocketFactory(sslSocketFactory)
                .hostnameVerifier(org.apache.http.conn.ssl.SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER).build();
        return okHttpClient;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

}

Iam using this client in retrofit like this

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

EDIT : adding the getUnsafeOkHttpClient() has no effect here and it is not at all recommended to bypass the ssl check by using getUnsafeOkHttpClient()

FYI : The issue was because the api endpoint supports only TLS 1.2 which was disabled by default on android devices 16<device<20 . So for 16<device<20, create a custom SSLSocketFactory

Answer 1

Finally found a solution to this issue, its not a complete solution as it is a hack mentioned by Jesse Wilson from okhttp, square here. As i mentioned it was a simple hack where 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;
private TrustManager[] trustManagers;

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

private void generateTrustManagers() throws KeyStoreException, NoSuchAlgorithmException {
    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
    trustManagerFactory.init((KeyStore) null);
    TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();

    if (trustManagers.length != 1 || !(trustManagers[0] instanceof X509TrustManager)) {
        throw new IllegalStateException("Unexpected default trust managers:"
                + Arrays.toString(trustManagers));
    }

    this.trustManagers = trustManagers;
}


@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;
}

@Nullable
public X509TrustManager getTrustManager() {
    return  (X509TrustManager) trustManagers[0];
}

}

and this is how i used it with okhttp and retrofit

 OkHttpClient client=new OkHttpClient();
    try {
        TLSSocketFactory tlsSocketFactory=new TLSSocketFactory();
        if (tlsSocketFactory.getTrustManager()!=null) {
            client = new OkHttpClient.Builder()
                    .sslSocketFactory(tlsSocketFactory, tlsSocketFactory.getTrustManager())
                    .build();
        }
    } catch (KeyManagementException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (KeyStoreException e) {
        e.printStackTrace();
    }

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

EDIT : The method public Builder sslSocketFactory(SSLSocketFactory sslSocketFactory) is now deprecated and we should use public Builder sslSocketFactory( SSLSocketFactory sslSocketFactory, X509TrustManager trustManager) as i have updated in the answer. This is because X509TrustManager is a field that OkHttp needs to build a clean certificate chain, which was not paased in the deprecated method.

You may also check this for more info