CustomTrustManager.java

/*
 * Copyright (C) 2012 Pixmob (http://github.com/pixmob)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.pixmob.httpclient;

import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.List;

import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

/**
 * {@link X509TrustManager} implementation for using custom SSL certificates.
 * This implementation comes from <a
 * href="http://goo.gl/vLA85">http://goo.gl/vLA85</a>.
 * @author Pixmob
 */
class CustomTrustManager implements X509TrustManager {
    static class LocalStoreX509TrustManager implements X509TrustManager {
        private X509TrustManager trustManager;
        
        LocalStoreX509TrustManager(KeyStore localTrustStore) {
            try {
                TrustManagerFactory tmf = TrustManagerFactory
                        .getInstance(TrustManagerFactory.getDefaultAlgorithm());
                tmf.init(localTrustStore);
                
                trustManager = findX509TrustManager(tmf);
                if (trustManager == null) {
                    throw new IllegalStateException(
                            "Couldn't find X509TrustManager");
                }
            } catch (GeneralSecurityException e) {
                throw new RuntimeException(e);
            }
            
        }
        
        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            trustManager.checkClientTrusted(chain, authType);
        }
        
        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            trustManager.checkServerTrusted(chain, authType);
        }
        
        public X509Certificate[] getAcceptedIssuers() {
            return trustManager.getAcceptedIssuers();
        }
    }
    
    static X509TrustManager findX509TrustManager(TrustManagerFactory tmf) {
        TrustManager tms[] = tmf.getTrustManagers();
        for (int i = 0; i < tms.length; i++) {
            if (tms[i] instanceof X509TrustManager) {
                return (X509TrustManager) tms[i];
            }
        }
        
        return null;
    }
    
    private X509TrustManager defaultTrustManager;
    private X509TrustManager localTrustManager;
    
    private X509Certificate[] acceptedIssuers;
    
    public CustomTrustManager(KeyStore localKeyStore) {
        try {
            TrustManagerFactory tmf = TrustManagerFactory
                    .getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init((KeyStore) null);
            
            defaultTrustManager = findX509TrustManager(tmf);
            if (defaultTrustManager == null) {
                throw new IllegalStateException(
                        "Couldn't find X509TrustManager");
            }
            
            localTrustManager = new LocalStoreX509TrustManager(localKeyStore);
            
            List<X509Certificate> allIssuers = new ArrayList<X509Certificate>();
            for (X509Certificate cert : defaultTrustManager
                    .getAcceptedIssuers()) {
                allIssuers.add(cert);
            }
            for (X509Certificate cert : localTrustManager.getAcceptedIssuers()) {
                allIssuers.add(cert);
            }
            acceptedIssuers = allIssuers.toArray(new X509Certificate[allIssuers
                    .size()]);
        } catch (GeneralSecurityException e) {
            throw new RuntimeException(e);
        }
        
    }
    
    public void checkClientTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
        try {
            defaultTrustManager.checkClientTrusted(chain, authType);
        } catch (CertificateException ce) {
            localTrustManager.checkClientTrusted(chain, authType);
        }
    }
    
    public void checkServerTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
        try {
            defaultTrustManager.checkServerTrusted(chain, authType);
        } catch (CertificateException ce) {
            localTrustManager.checkServerTrusted(chain, authType);
        }
    }
    
    public X509Certificate[] getAcceptedIssuers() {
        return acceptedIssuers;
    }
}