J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2002-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.security.validator; |
| 27 | |
| 28 | import java.io.IOException; |
| 29 | import java.util.*; |
| 30 | |
| 31 | import java.security.*; |
| 32 | import java.security.cert.*; |
| 33 | |
| 34 | import javax.security.auth.x500.X500Principal; |
| 35 | |
| 36 | import sun.security.x509.X509CertImpl; |
| 37 | import sun.security.x509.NetscapeCertTypeExtension; |
| 38 | import sun.security.util.DerValue; |
| 39 | import sun.security.util.DerInputStream; |
| 40 | import sun.security.util.DerOutputStream; |
| 41 | import sun.security.util.ObjectIdentifier; |
| 42 | |
| 43 | /** |
| 44 | * A simple validator implementation. It is based on code from the JSSE |
| 45 | * X509TrustManagerImpl. This implementation is designed for compatibility with |
| 46 | * deployed certificates and previous J2SE versions. It will never support |
| 47 | * more advanced features and will be deemphasized in favor of the PKIX |
| 48 | * validator going forward. |
| 49 | * |
| 50 | * @author Andreas Sterbenz |
| 51 | */ |
| 52 | public final class SimpleValidator extends Validator { |
| 53 | |
| 54 | // Constants for the OIDs we need |
| 55 | |
| 56 | final static String OID_BASIC_CONSTRAINTS = "2.5.29.19"; |
| 57 | |
| 58 | final static String OID_NETSCAPE_CERT_TYPE = "2.16.840.1.113730.1.1"; |
| 59 | |
| 60 | final static String OID_KEY_USAGE = "2.5.29.15"; |
| 61 | |
| 62 | final static String OID_EXTENDED_KEY_USAGE = "2.5.29.37"; |
| 63 | |
| 64 | final static String OID_EKU_ANY_USAGE = "2.5.29.37.0"; |
| 65 | |
| 66 | final static ObjectIdentifier OBJID_NETSCAPE_CERT_TYPE = |
| 67 | NetscapeCertTypeExtension.NetscapeCertType_Id; |
| 68 | |
| 69 | private final static String NSCT_SSL_CA = |
| 70 | NetscapeCertTypeExtension.SSL_CA; |
| 71 | |
| 72 | private final static String NSCT_CODE_SIGNING_CA = |
| 73 | NetscapeCertTypeExtension.OBJECT_SIGNING_CA; |
| 74 | |
| 75 | /** |
| 76 | * The trusted certificates as: |
| 77 | * Map (X500Principal)subject of trusted cert -> List of X509Certificate |
| 78 | * The list is used because there may be multiple certificates |
| 79 | * with an identical subject DN. |
| 80 | */ |
| 81 | private Map<X500Principal, List<X509Certificate>> trustedX500Principals; |
| 82 | |
| 83 | /** |
| 84 | * Set of the trusted certificates. Present only for |
| 85 | * getTrustedCertificates(). |
| 86 | */ |
| 87 | private Collection<X509Certificate> trustedCerts; |
| 88 | |
| 89 | SimpleValidator(String variant, Collection<X509Certificate> trustedCerts) { |
| 90 | super(TYPE_SIMPLE, variant); |
| 91 | this.trustedCerts = trustedCerts; |
| 92 | trustedX500Principals = |
| 93 | new HashMap<X500Principal, List<X509Certificate>>(); |
| 94 | for (X509Certificate cert : trustedCerts) { |
| 95 | X500Principal principal = cert.getSubjectX500Principal(); |
| 96 | List<X509Certificate> list = trustedX500Principals.get(principal); |
| 97 | if (list == null) { |
| 98 | // this actually should be a set, but duplicate entries |
| 99 | // are not a problem and we can avoid the Set overhead |
| 100 | list = new ArrayList<X509Certificate>(2); |
| 101 | trustedX500Principals.put(principal, list); |
| 102 | } |
| 103 | list.add(cert); |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | public Collection<X509Certificate> getTrustedCertificates() { |
| 108 | return trustedCerts; |
| 109 | } |
| 110 | |
| 111 | /** |
| 112 | * Perform simple validation of chain. The arguments otherCerts and |
| 113 | * parameter are ignored. |
| 114 | */ |
| 115 | X509Certificate[] engineValidate(X509Certificate[] chain, |
| 116 | Collection<X509Certificate> otherCerts, Object parameter) |
| 117 | throws CertificateException { |
| 118 | if ((chain == null) || (chain.length == 0)) { |
| 119 | throw new CertificateException |
| 120 | ("null or zero-length certificate chain"); |
| 121 | } |
| 122 | |
| 123 | // make sure chain includes a trusted cert |
| 124 | chain = buildTrustedChain(chain); |
| 125 | |
| 126 | Date date = validationDate; |
| 127 | if (date == null) { |
| 128 | date = new Date(); |
| 129 | } |
| 130 | // verify top down, starting at the certificate issued by |
| 131 | // the trust anchor |
| 132 | for (int i = chain.length - 2; i >= 0; i--) { |
| 133 | X509Certificate issuerCert = chain[i + 1]; |
| 134 | X509Certificate cert = chain[i]; |
| 135 | |
| 136 | |
| 137 | // no validity check for code signing certs |
| 138 | if ((variant.equals(VAR_CODE_SIGNING) == false) |
| 139 | && (variant.equals(VAR_JCE_SIGNING) == false)) { |
| 140 | cert.checkValidity(date); |
| 141 | } |
| 142 | |
| 143 | // check name chaining |
| 144 | if (cert.getIssuerX500Principal().equals( |
| 145 | issuerCert.getSubjectX500Principal()) == false) { |
| 146 | throw new ValidatorException |
| 147 | (ValidatorException.T_NAME_CHAINING, cert); |
| 148 | } |
| 149 | |
| 150 | // check signature |
| 151 | try { |
| 152 | cert.verify(issuerCert.getPublicKey()); |
| 153 | } catch (GeneralSecurityException e) { |
| 154 | throw new ValidatorException |
| 155 | (ValidatorException.T_SIGNATURE_ERROR, cert, e); |
| 156 | } |
| 157 | |
| 158 | // check extensions for CA certs |
| 159 | if (i != 0) { |
| 160 | checkExtensions(cert, i); |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | return chain; |
| 165 | } |
| 166 | |
| 167 | private void checkExtensions(X509Certificate cert, int index) |
| 168 | throws CertificateException { |
| 169 | Set<String> critSet = cert.getCriticalExtensionOIDs(); |
| 170 | if (critSet == null) { |
| 171 | critSet = Collections.<String>emptySet(); |
| 172 | } |
| 173 | |
| 174 | // Check the basic constraints extension |
| 175 | checkBasicConstraints(cert, critSet, index); |
| 176 | |
| 177 | // Check the key usage and extended key usage extensions |
| 178 | checkKeyUsage(cert, critSet); |
| 179 | |
| 180 | // check Netscape certificate type extension |
| 181 | checkNetscapeCertType(cert, critSet); |
| 182 | |
| 183 | if (!critSet.isEmpty()) { |
| 184 | throw new ValidatorException |
| 185 | ("Certificate contains unknown critical extensions: " + critSet, |
| 186 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | private void checkNetscapeCertType(X509Certificate cert, |
| 191 | Set<String> critSet) throws CertificateException { |
| 192 | if (variant.equals(VAR_GENERIC)) { |
| 193 | // nothing |
| 194 | } else if (variant.equals(VAR_TLS_CLIENT) |
| 195 | || variant.equals(VAR_TLS_SERVER)) { |
| 196 | if (getNetscapeCertTypeBit(cert, NSCT_SSL_CA) == false) { |
| 197 | throw new ValidatorException |
| 198 | ("Invalid Netscape CertType extension for SSL CA " |
| 199 | + "certificate", |
| 200 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 201 | } |
| 202 | critSet.remove(OID_NETSCAPE_CERT_TYPE); |
| 203 | } else if (variant.equals(VAR_CODE_SIGNING) |
| 204 | || variant.equals(VAR_JCE_SIGNING)) { |
| 205 | if (getNetscapeCertTypeBit(cert, NSCT_CODE_SIGNING_CA) == false) { |
| 206 | throw new ValidatorException |
| 207 | ("Invalid Netscape CertType extension for code " |
| 208 | + "signing CA certificate", |
| 209 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 210 | } |
| 211 | critSet.remove(OID_NETSCAPE_CERT_TYPE); |
| 212 | } else { |
| 213 | throw new CertificateException("Unknown variant " + variant); |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | /** |
| 218 | * Get the value of the specified bit in the Netscape certificate type |
| 219 | * extension. If the extension is not present at all, we return true. |
| 220 | */ |
| 221 | static boolean getNetscapeCertTypeBit(X509Certificate cert, String type) { |
| 222 | try { |
| 223 | NetscapeCertTypeExtension ext; |
| 224 | if (cert instanceof X509CertImpl) { |
| 225 | X509CertImpl certImpl = (X509CertImpl)cert; |
| 226 | ObjectIdentifier oid = OBJID_NETSCAPE_CERT_TYPE; |
| 227 | ext = (NetscapeCertTypeExtension)certImpl.getExtension(oid); |
| 228 | if (ext == null) { |
| 229 | return true; |
| 230 | } |
| 231 | } else { |
| 232 | byte[] extVal = cert.getExtensionValue(OID_NETSCAPE_CERT_TYPE); |
| 233 | if (extVal == null) { |
| 234 | return true; |
| 235 | } |
| 236 | DerInputStream in = new DerInputStream(extVal); |
| 237 | byte[] encoded = in.getOctetString(); |
| 238 | encoded = new DerValue(encoded).getUnalignedBitString() |
| 239 | .toByteArray(); |
| 240 | ext = new NetscapeCertTypeExtension(encoded); |
| 241 | } |
| 242 | Boolean val = (Boolean)ext.get(type); |
| 243 | return val.booleanValue(); |
| 244 | } catch (IOException e) { |
| 245 | return false; |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | private void checkBasicConstraints(X509Certificate cert, |
| 250 | Set<String> critSet, int index) throws CertificateException { |
| 251 | |
| 252 | critSet.remove(OID_BASIC_CONSTRAINTS); |
| 253 | int constraints = cert.getBasicConstraints(); |
| 254 | // reject, if extension missing or not a CA (constraints == -1) |
| 255 | if (constraints < 0) { |
| 256 | throw new ValidatorException("End user tried to act as a CA", |
| 257 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 258 | } |
| 259 | if (index - 1 > constraints) { |
| 260 | throw new ValidatorException("Violated path length constraints", |
| 261 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | /* |
| 266 | * Verify the key usage and extended key usage for intermediate |
| 267 | * certificates. |
| 268 | */ |
| 269 | private void checkKeyUsage(X509Certificate cert, Set<String> critSet) |
| 270 | throws CertificateException { |
| 271 | |
| 272 | critSet.remove(OID_KEY_USAGE); |
| 273 | // EKU irrelevant in CA certificates |
| 274 | critSet.remove(OID_EXTENDED_KEY_USAGE); |
| 275 | |
| 276 | // check key usage extension |
| 277 | boolean[] keyUsageInfo = cert.getKeyUsage(); |
| 278 | if (keyUsageInfo != null) { |
| 279 | // keyUsageInfo[5] is for keyCertSign. |
| 280 | if ((keyUsageInfo.length < 6) || (keyUsageInfo[5] == false)) { |
| 281 | throw new ValidatorException |
| 282 | ("Wrong key usage: expected keyCertSign", |
| 283 | ValidatorException.T_CA_EXTENSIONS, cert); |
| 284 | } |
| 285 | } |
| 286 | } |
| 287 | |
| 288 | /** |
| 289 | * Build a trusted certificate chain. This method always returns a chain |
| 290 | * with a trust anchor as the final cert in the chain. If no trust anchor |
| 291 | * could be found, a CertificateException is thrown. |
| 292 | */ |
| 293 | private X509Certificate[] buildTrustedChain(X509Certificate[] chain) |
| 294 | throws CertificateException { |
| 295 | List<X509Certificate> c = new ArrayList<X509Certificate>(chain.length); |
| 296 | // scan chain starting at EE cert |
| 297 | // if a trusted certificate is found, append it and return |
| 298 | for (int i = 0; i < chain.length; i++) { |
| 299 | X509Certificate cert = chain[i]; |
| 300 | X509Certificate trustedCert = getTrustedCertificate(cert); |
| 301 | if (trustedCert != null) { |
| 302 | c.add(trustedCert); |
| 303 | return c.toArray(CHAIN0); |
| 304 | } |
| 305 | c.add(cert); |
| 306 | } |
| 307 | // check if we can append a trusted cert |
| 308 | X509Certificate cert = chain[chain.length - 1]; |
| 309 | X500Principal subject = cert.getSubjectX500Principal(); |
| 310 | X500Principal issuer = cert.getIssuerX500Principal(); |
| 311 | if (subject.equals(issuer) == false) { |
| 312 | List<X509Certificate> list = trustedX500Principals.get(issuer); |
| 313 | if (list != null) { |
| 314 | X509Certificate trustedCert = list.iterator().next(); |
| 315 | c.add(trustedCert); |
| 316 | return c.toArray(CHAIN0); |
| 317 | } |
| 318 | } |
| 319 | // no trusted cert found, error |
| 320 | throw new ValidatorException(ValidatorException.T_NO_TRUST_ANCHOR); |
| 321 | } |
| 322 | |
| 323 | /** |
| 324 | * Return a trusted certificate that matches the input certificate, |
| 325 | * or null if no such certificate can be found. This method also handles |
| 326 | * cases where a CA re-issues a trust anchor with the same public key and |
| 327 | * same subject and issuer names but a new validity period, etc. |
| 328 | */ |
| 329 | private X509Certificate getTrustedCertificate(X509Certificate cert) { |
| 330 | Principal certSubjectName = cert.getSubjectX500Principal(); |
| 331 | List<X509Certificate> list = trustedX500Principals.get(certSubjectName); |
| 332 | if (list == null) { |
| 333 | return null; |
| 334 | } |
| 335 | |
| 336 | Principal certIssuerName = cert.getIssuerX500Principal(); |
| 337 | PublicKey certPublicKey = cert.getPublicKey(); |
| 338 | |
| 339 | for (X509Certificate mycert : list) { |
| 340 | if (mycert.equals(cert)) { |
| 341 | return cert; |
| 342 | } |
| 343 | if (!mycert.getIssuerX500Principal().equals(certIssuerName)) { |
| 344 | continue; |
| 345 | } |
| 346 | if (!mycert.getPublicKey().equals(certPublicKey)) { |
| 347 | continue; |
| 348 | } |
| 349 | |
| 350 | // All tests pass, this must be the one to use... |
| 351 | return mycert; |
| 352 | } |
| 353 | return null; |
| 354 | } |
| 355 | |
| 356 | } |