CertPathValidatorException : Trust anchor for certificate path not found - Retrofit Android

Question

I am creating an android application which uses https for communication with the server. I am using retrofit and OkHttp for making req

Answer 1

Here is Kotlin version.
Thanks you :)

         fun unSafeOkHttpClient() :OkHttpClient.Builder {
            val okHttpClient = OkHttpClient.Builder()
            try {
                // Create a trust manager that does not validate certificate chains
                val trustAllCerts:  Array<TrustManager> = arrayOf(object : X509TrustManager {
                    override fun checkClientTrusted(chain: Array<out X509Certificate>?, authType: String?){}
                    override fun checkServerTrusted(chain: Array<out X509Certificate>?, authType: String?) {}
                    override fun getAcceptedIssuers(): Array<X509Certificate>  = arrayOf()
                })

                // Install the all-trusting trust manager
                val  sslContext = SSLContext.getInstance("SSL")
                sslContext.init(null, trustAllCerts, SecureRandom())

                // Create an ssl socket factory with our all-trusting manager
                val sslSocketFactory = sslContext.socketFactory
                if (trustAllCerts.isNotEmpty() &&  trustAllCerts.first() is X509TrustManager) {
                    okHttpClient.sslSocketFactory(sslSocketFactory, trustAllCerts.first() as X509TrustManager)
                    okHttpClient.hostnameVerifier { _, _ -> true }
                }

                return okHttpClient
            } catch (e: Exception) {
                return okHttpClient
            }
        }

Answer 2

After a long reserch and digging too deep i found the solution of certificate pinning in android and yes its different from iOS where we need a certificate itself but in android we just need a hash pin and that's it.

How to get hash pin for certificate?

Initially just use a wrong hash pin and your java class will throw an error with correct hash pins or pin chain, just copy and paste into your code thats it.

This solution fixed my problem : https://stackoverflow.com/a/45853669/3448003

Answer 3

You are converting cert into BKS Keystore, why aren't you using .cert directly, from https://developer.android.com/training/articles/security-ssl.html:

CertificateFactory cf = CertificateFactory.getInstance("X.509");
InputStream instream = context.getResources().openRawResource(R.raw.gtux_cert);
Certificate ca;
try {
    ca = cf.generateCertificate(instream);
} finally {
    caInput.close();
}

KeyStore kStore = KeyStore.getInstance(KeyStore.getDefaultType());
kStore.load(null, null);
kStore.setCertificateEntry("ca", ca);

TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm(););
tmf.init(kStore);

SSLContext context = SSLContext.getInstance("TLS");
context.init(null, tmf.getTrustManagers(), null);

okHttpClient.setSslSocketFactory(context.getSocketFactory());

Answer 4

Implementation in Kotlin : Retrofit 2.3.0

private fun getUnsafeOkHttpClient(mContext: Context) : 
OkHttpClient.Builder? {


var mCertificateFactory : CertificateFactory = 
CertificateFactory.getInstance("X.509")
var mInputStream = mContext.resources.openRawResource(R.raw.cert)
            var mCertificate : Certificate = mCertificateFactory.generateCertificate(mInputStream)
        mInputStream.close()
val mKeyStoreType = KeyStore.getDefaultType()
val mKeyStore = KeyStore.getInstance(mKeyStoreType)
mKeyStore.load(null, null)
mKeyStore.setCertificateEntry("ca", mCertificate)

val mTmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm()
val mTrustManagerFactory = TrustManagerFactory.getInstance(mTmfAlgorithm)
mTrustManagerFactory.init(mKeyStore)

val mTrustManagers = mTrustManagerFactory.trustManagers

val mSslContext = SSLContext.getInstance("SSL")
mSslContext.init(null, mTrustManagers, null)
val mSslSocketFactory = mSslContext.socketFactory

val builder = OkHttpClient.Builder()
builder.sslSocketFactory(mSslSocketFactory, mTrustManagers[0] as X509TrustManager)
builder.hostnameVerifier { _, _ -> true }
return builder

}

Answer 5

 Use the below code to solve the CertPathValidatorException issue.


 Retrofit retrofit = new Retrofit.Builder()
        .baseUrl(YOUR_BASE_URL)
        .client(getUnsafeOkHttpClient().build())
        .build();


  public static OkHttpClient.Builder getUnsafeOkHttpClient() {

    try {
        // Create a trust manager that does not validate certificate chains
        final TrustManager[] trustAllCerts = new TrustManager[]{
                new X509TrustManager() {
                    @Override
                    public void checkClientTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                    }

                    @Override
                    public void checkServerTrusted(java.security.cert.X509Certificate[] chain, String authType) throws CertificateException {
                    }

                    @Override
                    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                        return new java.security.cert.X509Certificate[]{};
                    }
                }
        };

        // Install the all-trusting trust manager
        final SSLContext sslContext = SSLContext.getInstance("SSL");
        sslContext.init(null, trustAllCerts, new java.security.SecureRandom());

        // Create an ssl socket factory with our all-trusting manager
        final SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();

        OkHttpClient.Builder builder = new OkHttpClient.Builder();
        builder.sslSocketFactory(sslSocketFactory, (X509TrustManager) trustAllCerts[0]);
        builder.hostnameVerifier(new HostnameVerifier() {
            @Override
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        });
        return builder;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

For more details visit https://mobikul.com/android-retrofit-handling-sslhandshakeexception/

Answer 6

DISCLAIMER: this answer is from Jul 2015 and uses Retrofit and OkHttp from that time.
Check this link for more info on Retrofit v2 and this one for the current OkHttp methods.

Okay, I got it working using Android Developers guide.

Just as OP, I'm trying to use Retrofit and OkHttp to connect to a self-signed SSL-enabled server.

Here's the code that got things working (I've removed the try/catch blocks):

public static RestAdapter createAdapter(Context context) {
  // loading CAs from an InputStream
  CertificateFactory cf = CertificateFactory.getInstance("X.509");
  InputStream cert = context.getResources().openRawResource(R.raw.my_cert);
  Certificate ca;
  try {
    ca = cf.generateCertificate(cert);
  } finally { cert.close(); }

  // creating a KeyStore containing our trusted CAs
  String keyStoreType = KeyStore.getDefaultType();
  KeyStore keyStore = KeyStore.getInstance(keyStoreType);
  keyStore.load(null, null);
  keyStore.setCertificateEntry("ca", ca);

  // creating a TrustManager that trusts the CAs in our KeyStore
  String tmfAlgorithm = TrustManagerFactory.getDefaultAlgorithm();
  TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmfAlgorithm);
  tmf.init(keyStore);

  // creating an SSLSocketFactory that uses our TrustManager
  SSLContext sslContext = SSLContext.getInstance("TLS");
  sslContext.init(null, tmf.getTrustManagers(), null);

  // creating an OkHttpClient that uses our SSLSocketFactory
  OkHttpClient okHttpClient = new OkHttpClient();
  okHttpClient.setSslSocketFactory(sslContext.getSocketFactory());

  // creating a RestAdapter that uses this custom client
  return new RestAdapter.Builder()
              .setEndpoint(UrlRepository.API_BASE)
              .setClient(new OkClient(okHttpClient))
              .build();
}

To help in debugging, I also added .setLogLevel(RestAdapter.LogLevel.FULL) to my RestAdapter creation commands and I could see it connecting and getting the response from the server.

All it took was my original .crt file saved in main/res/raw. The .crt file, aka the certificate, is one of the two files created when you create a certificate using openssl. Generally, it is a .crt or .cert file, while the other is a .key file.

Afaik, the .crt file is your public key and the .key file is your private key.

As I can see, you already have a .cert file, which is the same, so try to use it.

---

PS: For those that read it in the future and only have a .pem file, according to this answer, you only need this to convert one to the other:

openssl x509 -outform der -in your-cert.pem -out your-cert.crt

---

PS²: For those that don't have any file at all, you can use the following command (bash) to extract the public key (aka certificate) from any server:

echo -n | openssl s_client -connect your.server.com:443 | \
  sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ~/my_cert.crt

Just replace the your.server.com and the port (if it is not standard HTTPS) and choose a valid path for your output file to be created.