How do I initialize a TrustManagerFactory with multiple sources of trust?

Question

My application has a personal keystore containing trusted self-signed certificates for use in the local network - say mykeystore.jks. I wish to be able to connect to public sites(say google.com) as well as ones in my local network using self-signed certificates which have been provisioned locally.

The problem here is that, when I connect to https://google.com, path building fails, because setting my own keystore overrides the default keystore containing root CAs bundled with the JRE, reporting the exception

sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

However, if I import a CA certificate into my own keystore(mykeystore.jks) it works fine. Is there a way to support both?

I have my own TrustManger for this purpose,

public class CustomX509TrustManager implements X509TrustManager {

        X509TrustManager defaultTrustManager;

        public MyX509TrustManager(KeyStore keystore) {
                TrustManagerFactory trustMgrFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
                trustMgrFactory.init(keystore);
                TrustManager trustManagers[] = trustMgrFactory.getTrustManagers();
                for (int i = 0; i < trustManagers.length; i++) {
                    if (trustManagers[i] instanceof X509TrustManager) {
                        defaultTrustManager = (X509TrustManager) trustManagers[i];
                        return;
                    }
                }

        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            try {
                defaultTrustManager.checkServerTrusted(chain, authType);
            } catch (CertificateException ce) {
            /* Handle untrusted certificates */
            }
        }
    }

I then initialize the SSLContext,

TrustManager[] trustManagers =
            new TrustManager[] { new CustomX509TrustManager(keystore) };
SSLContext customSSLContext =
        SSLContext.getInstance("TLS");
customSSLContext.init(null, trustManagers, null);

and set the socket factory,

HttpsURLConnection.setDefaultSSLSocketFactory(customSSLContext.getSocketFactory());

The main program,

URL targetServer = new URL(url);
HttpsURLConnection conn = (HttpsURLConnection) targetServer.openConnection();

If I don't set my own trust managers, it connects to https://google.com just fine. How do I get a "default trust manager" which points to the default key store?

Answer 1

In trustMgrFactory.init(keystore); you're configuring defaultTrustManager with your own personal keystore, not the system default keystore.

Based on reading the source code for sun.security.ssl.TrustManagerFactoryImpl, it looks like trustMgrFactory.init((KeyStore) null); would do exactly what you need (load the system default keystore), and based on quick testing, it seems to work for me.