src/com/owncloud/android/network/AdvancedX509TrustManager.java

   1 /* ownCloud Android client application
   2  *   Copyright (C) 2012 Bartek Przybylski
   3  *
   4  *   This program is free software: you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License as published by
   6  *   the Free Software Foundation, either version 3 of the License, or
   7  *   (at your option) any later version.
   8  *
   9  *   This program is distributed in the hope that it will be useful,
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *   GNU General Public License for more details.
  13  *
  14  *   You should have received a copy of the GNU General Public License
  15  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  */
  18
  19 package com.owncloud.android.network;
  20
  21 import java.security.KeyStore;
  22 import java.security.KeyStoreException;
  23 import java.security.NoSuchAlgorithmException;
  24 import java.security.cert.CertStoreException;
  25 import java.security.cert.CertificateException;
  26 import java.security.cert.X509Certificate;
  27
  28 import javax.net.ssl.TrustManager;
  29 import javax.net.ssl.TrustManagerFactory;
  30 import javax.net.ssl.X509TrustManager;
  31
  32 import android.util.Log;
  33
  34 /**
  35  * @author David A. Velasco
  36  */
  37 public class AdvancedX509TrustManager implements X509TrustManager {
  38
  39     private static final String TAG = AdvancedX509TrustManager.class.getSimpleName();
  40
  41     private X509TrustManager mStandardTrustManager = null;
  42     private KeyStore mKnownServersKeyStore;
  43
  44     /**
  45      * Constructor for AdvancedX509TrustManager
  46      *
  47      * @param  knownServersCertStore    Local certificates store with server certificates explicitly trusted by the user.
  48      * @throws CertStoreException       When no default X509TrustManager instance was found in the system.
  49      */
  50     public AdvancedX509TrustManager(KeyStore knownServersKeyStore)
  51             throws NoSuchAlgorithmException, KeyStoreException, CertStoreException {
  52         super();
  53         TrustManagerFactory factory = TrustManagerFactory
  54                 .getInstance(TrustManagerFactory.getDefaultAlgorithm());
  55         factory.init((KeyStore)null);
  56         mStandardTrustManager = findX509TrustManager(factory);
  57
  58         mKnownServersKeyStore = knownServersKeyStore;
  59     }
  60
  61
  62     /**
  63      * Locates the first X509TrustManager provided by a given TrustManagerFactory
  64      * @param factory               TrustManagerFactory to inspect in the search for a X509TrustManager
  65      * @return                      The first X509TrustManager found in factory.
  66      * @throws CertStoreException   When no X509TrustManager instance was found in factory
  67      */
  68     private X509TrustManager findX509TrustManager(TrustManagerFactory factory) throws CertStoreException {
  69         TrustManager tms[] = factory.getTrustManagers();
  70         for (int i = 0; i < tms.length; i++) {
  71             if (tms[i] instanceof X509TrustManager) {
  72                 return (X509TrustManager) tms[i];
  73             }
  74         }
  75         return null;
  76     }
  77
  78
  79     /**
  80      * @see javax.net.ssl.X509TrustManager#checkClientTrusted(X509Certificate[],
  81      *      String authType)
  82      */
  83     public void checkClientTrusted(X509Certificate[] certificates, String authType) throws CertificateException {
  84         mStandardTrustManager.checkClientTrusted(certificates, authType);
  85     }
  86
  87
  88     /**
  89      * @see javax.net.ssl.X509TrustManager#checkServerTrusted(X509Certificate[],
  90      *      String authType)
  91      */
  92     public void checkServerTrusted(X509Certificate[] certificates, String authType) throws CertificateException {
  93         if (!isKnownServer(certificates[0])) {
  94             Log.d(TAG, "checkClientTrusted() with standard trust manager...");
  95             mStandardTrustManager.checkClientTrusted(certificates, authType);
  96         }
  97     }
  98
  99
 100     /**
 101      * @see javax.net.ssl.X509TrustManager#getAcceptedIssuers()
 102      */
 103     public X509Certificate[] getAcceptedIssuers() {
 104         return mStandardTrustManager.getAcceptedIssuers();
 105     }
 106
 107
 108     private boolean isKnownServer(X509Certificate cert) {
 109         try {
 110             return (mKnownServersKeyStore.getCertificateAlias(cert) != null);
 111         } catch (KeyStoreException e) {
 112             Log.d(TAG, "Fail while checking certificate in the known-servers store");
 113             return false;
 114         }
 115     }
 116
 117 }