| 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | package org.chromium.net; |
| 6 | |
| 7 | import android.util.Log; |
| 8 | |
| 9 | import org.chromium.net.CertVerifyResultAndroid; |
| 10 | |
| 11 | import java.io.ByteArrayInputStream; |
| 12 | import java.io.IOException; |
| 13 | import java.security.KeyStore; |
| 14 | import java.security.KeyStoreException; |
| 15 | import java.security.NoSuchAlgorithmException; |
| 16 | import java.security.cert.CertificateException; |
| 17 | import java.security.cert.CertificateExpiredException; |
| 18 | import java.security.cert.CertificateNotYetValidException; |
| 19 | import java.security.cert.CertificateFactory; |
| 20 | import java.security.cert.CertificateParsingException; |
| 21 | import java.security.cert.X509Certificate; |
| 22 | import java.util.List; |
| 23 | |
| 24 | import javax.net.ssl.TrustManager; |
| 25 | import javax.net.ssl.TrustManagerFactory; |
| 26 | import javax.net.ssl.X509TrustManager; |
| 27 | |
| 28 | public class X509Util { |
| 29 | |
| 30 | private static final String TAG = "X509Util"; |
| 31 | |
| 32 | private static CertificateFactory sCertificateFactory; |
| 33 | |
| 34 | private static final String OID_TLS_SERVER_AUTH = "1.3.6.1.5.5.7.3.1"; |
| 35 | private static final String OID_ANY_EKU = "2.5.29.37.0"; |
| 36 | // Server-Gated Cryptography (necessary to support a few legacy issuers): |
| 37 | // Netscape: |
| 38 | private static final String OID_SERVER_GATED_NETSCAPE = "2.16.840.1.113730.4.1"; |
| 39 | // Microsoft: |
| 40 | private static final String OID_SERVER_GATED_MICROSOFT = "1.3.6.1.4.1.311.10.3.3"; |
| 41 | |
| 42 | /** |
| 43 | * Trust manager backed up by the read-only system certificate store. |
| 44 | */ |
| 45 | private static X509TrustManager sDefaultTrustManager; |
| 46 | |
| 47 | /** |
| 48 | * Trust manager backed up by a custom certificate store. We need such manager to plant test |
| 49 | * root CA to the trust store in testing. |
| 50 | */ |
| 51 | private static X509TrustManager sTestTrustManager; |
| 52 | private static KeyStore sTestKeyStore; |
| 53 | |
| 54 | /** |
| 55 | * Lock object used to synchronize all calls that modify or depend on the trust managers. |
| 56 | */ |
| 57 | private static final Object sLock = new Object(); |
| 58 | |
| 59 | /** |
| 60 | * Ensures that the trust managers and certificate factory are initialized. |
| 61 | */ |
| 62 | private static void ensureInitialized() throws CertificateException, |
| 63 | KeyStoreException, NoSuchAlgorithmException { |
| 64 | synchronized(sLock) { |
| 65 | if (sCertificateFactory == null) { |
| 66 | sCertificateFactory = CertificateFactory.getInstance("X.509"); |
| 67 | } |
| 68 | if (sDefaultTrustManager == null) { |
| 69 | sDefaultTrustManager = X509Util.createTrustManager(null); |
| 70 | } |
| 71 | if (sTestKeyStore == null) { |
| 72 | sTestKeyStore = KeyStore.getInstance(KeyStore.getDefaultType()); |
| 73 | try { |
| 74 | sTestKeyStore.load(null); |
| 75 | } catch(IOException e) {} // No IO operation is attempted. |
| 76 | } |
| 77 | if (sTestTrustManager == null) { |
| 78 | sTestTrustManager = X509Util.createTrustManager(sTestKeyStore); |
| 79 | } |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Creates a X509TrustManager backed up by the given key store. When null is passed as a key |
| 85 | * store, system default trust store is used. |
| 86 | * @throws KeyStoreException, NoSuchAlgorithmException on error initializing the TrustManager. |
| 87 | */ |
| 88 | private static X509TrustManager createTrustManager(KeyStore keyStore) throws KeyStoreException, |
| 89 | NoSuchAlgorithmException { |
| 90 | String algorithm = TrustManagerFactory.getDefaultAlgorithm(); |
| 91 | TrustManagerFactory tmf = TrustManagerFactory.getInstance(algorithm); |
| 92 | tmf.init(keyStore); |
| 93 | |
| 94 | for (TrustManager tm : tmf.getTrustManagers()) { |
| 95 | if (tm instanceof X509TrustManager) { |
| 96 | return (X509TrustManager) tm; |
| 97 | } |
| 98 | } |
| 99 | return null; |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * After each modification of test key store, trust manager has to be generated again. |
| 104 | */ |
| 105 | private static void reloadTestTrustManager() throws KeyStoreException, |
| 106 | NoSuchAlgorithmException { |
| 107 | sTestTrustManager = X509Util.createTrustManager(sTestKeyStore); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Convert a DER encoded certificate to an X509Certificate. |
| 112 | */ |
| 113 | public static X509Certificate createCertificateFromBytes(byte[] derBytes) throws |
| 114 | CertificateException, KeyStoreException, NoSuchAlgorithmException { |
| 115 | ensureInitialized(); |
| 116 | return (X509Certificate) sCertificateFactory.generateCertificate( |
| 117 | new ByteArrayInputStream(derBytes)); |
| 118 | } |
| 119 | |
| 120 | public static void addTestRootCertificate(byte[] rootCertBytes) throws CertificateException, |
| 121 | KeyStoreException, NoSuchAlgorithmException { |
| 122 | ensureInitialized(); |
| 123 | X509Certificate rootCert = createCertificateFromBytes(rootCertBytes); |
| 124 | synchronized (sLock) { |
| 125 | sTestKeyStore.setCertificateEntry( |
| 126 | "root_cert_" + Integer.toString(sTestKeyStore.size()), rootCert); |
| 127 | reloadTestTrustManager(); |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | public static void clearTestRootCertificates() throws NoSuchAlgorithmException, |
| 132 | CertificateException, KeyStoreException { |
| 133 | ensureInitialized(); |
| 134 | synchronized (sLock) { |
| 135 | try { |
| 136 | sTestKeyStore.load(null); |
| 137 | reloadTestTrustManager(); |
| 138 | } catch (IOException e) {} // No IO operation is attempted. |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * If an EKU extension is present in the end-entity certificate, it MUST contain either the |
| 144 | * anyEKU or serverAuth or netscapeSGC or Microsoft SGC EKUs. |
| 145 | * |
| 146 | * @return true if there is no EKU extension or if any of the EKU extensions is one of the valid |
| 147 | * OIDs for web server certificates. |
| 148 | * |
| 149 | * TODO(palmer): This can be removed after the equivalent change is made to the Android default |
| 150 | * TrustManager and that change is shipped to a large majority of Android users. |
| 151 | */ |
| 152 | static boolean verifyKeyUsage(X509Certificate certificate) throws CertificateException { |
| 153 | List<String> ekuOids; |
| 154 | try { |
| 155 | ekuOids = certificate.getExtendedKeyUsage(); |
| 156 | } catch (NullPointerException e) { |
| 157 | // getExtendedKeyUsage() can crash due to an Android platform bug. This probably |
| 158 | // happens when the EKU extension data is malformed so return false here. |
| 159 | // See http://crbug.com/233610 |
| 160 | return false; |
| 161 | } |
| 162 | if (ekuOids == null) |
| 163 | return true; |
| 164 | |
| 165 | for (String ekuOid : ekuOids) { |
| 166 | if (ekuOid.equals(OID_TLS_SERVER_AUTH) || |
| 167 | ekuOid.equals(OID_ANY_EKU) || |
| 168 | ekuOid.equals(OID_SERVER_GATED_NETSCAPE) || |
| 169 | ekuOid.equals(OID_SERVER_GATED_MICROSOFT)) { |
| 170 | return true; |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | return false; |
| 175 | } |
| 176 | |
| 177 | public static int verifyServerCertificates(byte[][] certChain, String authType) |
| 178 | throws KeyStoreException, NoSuchAlgorithmException { |
| 179 | if (certChain == null || certChain.length == 0 || certChain[0] == null) { |
| 180 | throw new IllegalArgumentException("Expected non-null and non-empty certificate " + |
| 181 | "chain passed as |certChain|. |certChain|=" + certChain); |
| 182 | } |
| 183 | |
| 184 | try { |
| 185 | ensureInitialized(); |
| 186 | } catch (CertificateException e) { |
| 187 | return CertVerifyResultAndroid.VERIFY_FAILED; |
| 188 | } |
| 189 | |
| 190 | X509Certificate[] serverCertificates = new X509Certificate[certChain.length]; |
| 191 | try { |
| 192 | for (int i = 0; i < certChain.length; ++i) { |
| 193 | serverCertificates[i] = createCertificateFromBytes(certChain[i]); |
| 194 | } |
| 195 | } catch (CertificateException e) { |
| 196 | return CertVerifyResultAndroid.VERIFY_UNABLE_TO_PARSE; |
| 197 | } |
| 198 | |
| 199 | // Expired and not yet valid certificates would be rejected by the trust managers, but the |
| 200 | // trust managers report all certificate errors using the general CertificateException. In |
| 201 | // order to get more granular error information, cert validity time range is being checked |
| 202 | // separately. |
| 203 | try { |
| 204 | serverCertificates[0].checkValidity(); |
| 205 | if (!verifyKeyUsage(serverCertificates[0])) |
| 206 | return CertVerifyResultAndroid.VERIFY_INCORRECT_KEY_USAGE; |
| 207 | } catch (CertificateExpiredException e) { |
| 208 | return CertVerifyResultAndroid.VERIFY_EXPIRED; |
| 209 | } catch (CertificateNotYetValidException e) { |
| 210 | return CertVerifyResultAndroid.VERIFY_NOT_YET_VALID; |
| 211 | } catch (CertificateException e) { |
| 212 | return CertVerifyResultAndroid.VERIFY_FAILED; |
| 213 | } |
| 214 | |
| 215 | synchronized (sLock) { |
| 216 | try { |
| 217 | sDefaultTrustManager.checkServerTrusted(serverCertificates, authType); |
| 218 | return CertVerifyResultAndroid.VERIFY_OK; |
| 219 | } catch (CertificateException eDefaultManager) { |
| 220 | try { |
| 221 | sTestTrustManager.checkServerTrusted(serverCertificates, authType); |
| 222 | return CertVerifyResultAndroid.VERIFY_OK; |
| 223 | } catch (CertificateException eTestManager) { |
| 224 | // Neither of the trust managers confirms the validity of the certificate chain, |
| 225 | // log the error message returned by the system trust manager. |
| 226 | Log.i(TAG, "Failed to validate the certificate chain, error: " + |
| 227 | eDefaultManager.getMessage()); |
| 228 | return CertVerifyResultAndroid.VERIFY_NO_TRUSTED_ROOT; |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | } |
| 233 | } |