1 /* 2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.security.x509; 27 28 import java.io.IOException; 29 import java.io.OutputStream; 30 import java.security.cert.CertificateException; 31 import java.security.cert.X509Certificate; 32 import java.util.*; 33 34 import javax.security.auth.x500.X500Principal; 35 36 import sun.security.util.*; 37 import sun.security.pkcs.PKCS9Attribute; 38 39 /** 40 * This class defines the Name Constraints Extension. 41 * <p> 42 * The name constraints extension provides permitted and excluded 43 * subtrees that place restrictions on names that may be included within 44 * a certificate issued by a given CA. Restrictions may apply to the 45 * subject distinguished name or subject alternative names. Any name 46 * matching a restriction in the excluded subtrees field is invalid 47 * regardless of information appearing in the permitted subtrees. 48 * <p> 49 * The ASN.1 syntax for this is: 50 * <pre> 51 * NameConstraints ::= SEQUENCE { 52 * permittedSubtrees [0] GeneralSubtrees OPTIONAL, 53 * excludedSubtrees [1] GeneralSubtrees OPTIONAL 54 * } 55 * GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree 56 * </pre> 57 * 58 * @author Amit Kapoor 59 * @author Hemma Prafullchandra 60 * @see Extension 61 * @see CertAttrSet 62 */ 63 public class NameConstraintsExtension extends Extension 64 implements CertAttrSet<String>, Cloneable { 65 /** 66 * Identifier for this attribute, to be used with the 67 * get, set, delete methods of Certificate, x509 type. 68 */ 69 public static final String IDENT = "x509.info.extensions.NameConstraints"; 70 /** 71 * Attribute names. 72 */ 73 public static final String NAME = "NameConstraints"; 74 public static final String PERMITTED_SUBTREES = "permitted_subtrees"; 75 public static final String EXCLUDED_SUBTREES = "excluded_subtrees"; 76 77 // Private data members 78 private static final byte TAG_PERMITTED = 0; 79 private static final byte TAG_EXCLUDED = 1; 80 81 private GeneralSubtrees permitted = null; 82 private GeneralSubtrees excluded = null; 83 84 private boolean hasMin; 85 private boolean hasMax; 86 private boolean minMaxValid = false; 87 88 // Recalculate hasMin and hasMax flags. calcMinMax()89 private void calcMinMax() throws IOException { 90 hasMin = false; 91 hasMax = false; 92 if (excluded != null) { 93 for (int i = 0; i < excluded.size(); i++) { 94 GeneralSubtree subtree = excluded.get(i); 95 if (subtree.getMinimum() != 0) 96 hasMin = true; 97 if (subtree.getMaximum() != -1) 98 hasMax = true; 99 } 100 } 101 102 if (permitted != null) { 103 for (int i = 0; i < permitted.size(); i++) { 104 GeneralSubtree subtree = permitted.get(i); 105 if (subtree.getMinimum() != 0) 106 hasMin = true; 107 if (subtree.getMaximum() != -1) 108 hasMax = true; 109 } 110 } 111 minMaxValid = true; 112 } 113 114 // Encode this extension value. encodeThis()115 private void encodeThis() throws IOException { 116 minMaxValid = false; 117 if (permitted == null && excluded == null) { 118 this.extensionValue = null; 119 return; 120 } 121 DerOutputStream seq = new DerOutputStream(); 122 123 DerOutputStream tagged = new DerOutputStream(); 124 if (permitted != null) { 125 DerOutputStream tmp = new DerOutputStream(); 126 permitted.encode(tmp); 127 tagged.writeImplicit(DerValue.createTag(DerValue.TAG_CONTEXT, 128 true, TAG_PERMITTED), tmp); 129 } 130 if (excluded != null) { 131 DerOutputStream tmp = new DerOutputStream(); 132 excluded.encode(tmp); 133 tagged.writeImplicit(DerValue.createTag(DerValue.TAG_CONTEXT, 134 true, TAG_EXCLUDED), tmp); 135 } 136 seq.write(DerValue.tag_Sequence, tagged); 137 this.extensionValue = seq.toByteArray(); 138 } 139 140 /** 141 * The default constructor for this class. Both parameters 142 * are optional and can be set to null. The extension criticality 143 * is set to true. 144 * 145 * @param permitted the permitted GeneralSubtrees (null for optional). 146 * @param excluded the excluded GeneralSubtrees (null for optional). 147 */ NameConstraintsExtension(GeneralSubtrees permitted, GeneralSubtrees excluded)148 public NameConstraintsExtension(GeneralSubtrees permitted, 149 GeneralSubtrees excluded) 150 throws IOException { 151 this.permitted = permitted; 152 this.excluded = excluded; 153 154 this.extensionId = PKIXExtensions.NameConstraints_Id; 155 this.critical = true; 156 encodeThis(); 157 } 158 159 /** 160 * Create the extension from the passed DER encoded value. 161 * 162 * @param critical true if the extension is to be treated as critical. 163 * @param value an array of DER encoded bytes of the actual value. 164 * @exception ClassCastException if value is not an array of bytes 165 * @exception IOException on error. 166 */ NameConstraintsExtension(Boolean critical, Object value)167 public NameConstraintsExtension(Boolean critical, Object value) 168 throws IOException { 169 this.extensionId = PKIXExtensions.NameConstraints_Id; 170 this.critical = critical.booleanValue(); 171 172 this.extensionValue = (byte[]) value; 173 DerValue val = new DerValue(this.extensionValue); 174 if (val.tag != DerValue.tag_Sequence) { 175 throw new IOException("Invalid encoding for" + 176 " NameConstraintsExtension."); 177 } 178 179 // NB. this is always encoded with the IMPLICIT tag 180 // The checks only make sense if we assume implicit tagging, 181 // with explicit tagging the form is always constructed. 182 // Note that all the fields in NameConstraints are defined as 183 // being OPTIONAL, i.e., there could be an empty SEQUENCE, resulting 184 // in val.data being null. 185 if (val.data == null) 186 return; 187 while (val.data.available() != 0) { 188 DerValue opt = val.data.getDerValue(); 189 190 if (opt.isContextSpecific(TAG_PERMITTED) && opt.isConstructed()) { 191 if (permitted != null) { 192 throw new IOException("Duplicate permitted " + 193 "GeneralSubtrees in NameConstraintsExtension."); 194 } 195 opt.resetTag(DerValue.tag_Sequence); 196 permitted = new GeneralSubtrees(opt); 197 198 } else if (opt.isContextSpecific(TAG_EXCLUDED) && 199 opt.isConstructed()) { 200 if (excluded != null) { 201 throw new IOException("Duplicate excluded " + 202 "GeneralSubtrees in NameConstraintsExtension."); 203 } 204 opt.resetTag(DerValue.tag_Sequence); 205 excluded = new GeneralSubtrees(opt); 206 } else 207 throw new IOException("Invalid encoding of " + 208 "NameConstraintsExtension."); 209 } 210 minMaxValid = false; 211 } 212 213 /** 214 * Return the printable string. 215 */ toString()216 public String toString() { 217 return (super.toString() + "NameConstraints: [" + 218 ((permitted == null) ? "" : 219 ("\n Permitted:" + permitted.toString())) + 220 ((excluded == null) ? "" : 221 ("\n Excluded:" + excluded.toString())) 222 + " ]\n"); 223 } 224 225 /** 226 * Write the extension to the OutputStream. 227 * 228 * @param out the OutputStream to write the extension to. 229 * @exception IOException on encoding errors. 230 */ encode(OutputStream out)231 public void encode(OutputStream out) throws IOException { 232 DerOutputStream tmp = new DerOutputStream(); 233 if (this.extensionValue == null) { 234 this.extensionId = PKIXExtensions.NameConstraints_Id; 235 this.critical = true; 236 encodeThis(); 237 } 238 super.encode(tmp); 239 out.write(tmp.toByteArray()); 240 } 241 242 /** 243 * Set the attribute value. 244 */ set(String name, Object obj)245 public void set(String name, Object obj) throws IOException { 246 if (name.equalsIgnoreCase(PERMITTED_SUBTREES)) { 247 if (!(obj instanceof GeneralSubtrees)) { 248 throw new IOException("Attribute value should be" 249 + " of type GeneralSubtrees."); 250 } 251 permitted = (GeneralSubtrees)obj; 252 } else if (name.equalsIgnoreCase(EXCLUDED_SUBTREES)) { 253 if (!(obj instanceof GeneralSubtrees)) { 254 throw new IOException("Attribute value should be " 255 + "of type GeneralSubtrees."); 256 } 257 excluded = (GeneralSubtrees)obj; 258 } else { 259 throw new IOException("Attribute name not recognized by " + 260 "CertAttrSet:NameConstraintsExtension."); 261 } 262 encodeThis(); 263 } 264 265 /** 266 * Get the attribute value. 267 */ get(String name)268 public GeneralSubtrees get(String name) throws IOException { 269 if (name.equalsIgnoreCase(PERMITTED_SUBTREES)) { 270 return (permitted); 271 } else if (name.equalsIgnoreCase(EXCLUDED_SUBTREES)) { 272 return (excluded); 273 } else { 274 throw new IOException("Attribute name not recognized by " + 275 "CertAttrSet:NameConstraintsExtension."); 276 } 277 } 278 279 /** 280 * Delete the attribute value. 281 */ delete(String name)282 public void delete(String name) throws IOException { 283 if (name.equalsIgnoreCase(PERMITTED_SUBTREES)) { 284 permitted = null; 285 } else if (name.equalsIgnoreCase(EXCLUDED_SUBTREES)) { 286 excluded = null; 287 } else { 288 throw new IOException("Attribute name not recognized by " + 289 "CertAttrSet:NameConstraintsExtension."); 290 } 291 encodeThis(); 292 } 293 294 /** 295 * Return an enumeration of names of attributes existing within this 296 * attribute. 297 */ getElements()298 public Enumeration<String> getElements() { 299 AttributeNameEnumeration elements = new AttributeNameEnumeration(); 300 elements.addElement(PERMITTED_SUBTREES); 301 elements.addElement(EXCLUDED_SUBTREES); 302 303 return (elements.elements()); 304 } 305 306 /** 307 * Return the name of this attribute. 308 */ getName()309 public String getName() { 310 return (NAME); 311 } 312 313 /** 314 * Merge additional name constraints with existing ones. 315 * This function is used in certification path processing 316 * to accumulate name constraints from successive certificates 317 * in the path. Note that NameConstraints can never be 318 * expanded by a merge, just remain constant or become more 319 * limiting. 320 * <p> 321 * IETF RFC2459 specifies the processing of Name Constraints as 322 * follows: 323 * <p> 324 * (j) If permittedSubtrees is present in the certificate, set the 325 * constrained subtrees state variable to the intersection of its 326 * previous value and the value indicated in the extension field. 327 * <p> 328 * (k) If excludedSubtrees is present in the certificate, set the 329 * excluded subtrees state variable to the union of its previous 330 * value and the value indicated in the extension field. 331 * <p> 332 * @param newConstraints additional NameConstraints to be applied 333 * @throws IOException on error 334 */ merge(NameConstraintsExtension newConstraints)335 public void merge(NameConstraintsExtension newConstraints) 336 throws IOException { 337 338 if (newConstraints == null) { 339 // absence of any explicit constraints implies unconstrained 340 return; 341 } 342 343 /* 344 * If excludedSubtrees is present in the certificate, set the 345 * excluded subtrees state variable to the union of its previous 346 * value and the value indicated in the extension field. 347 */ 348 349 GeneralSubtrees newExcluded = newConstraints.get(EXCLUDED_SUBTREES); 350 if (excluded == null) { 351 excluded = (newExcluded != null) ? 352 (GeneralSubtrees)newExcluded.clone() : null; 353 } else { 354 if (newExcluded != null) { 355 // Merge new excluded with current excluded (union) 356 excluded.union(newExcluded); 357 } 358 } 359 360 /* 361 * If permittedSubtrees is present in the certificate, set the 362 * constrained subtrees state variable to the intersection of its 363 * previous value and the value indicated in the extension field. 364 */ 365 366 GeneralSubtrees newPermitted = newConstraints.get(PERMITTED_SUBTREES); 367 if (permitted == null) { 368 permitted = (newPermitted != null) ? 369 (GeneralSubtrees)newPermitted.clone() : null; 370 } else { 371 if (newPermitted != null) { 372 // Merge new permitted with current permitted (intersection) 373 newExcluded = permitted.intersect(newPermitted); 374 375 // Merge new excluded subtrees to current excluded (union) 376 if (newExcluded != null) { 377 if (excluded != null) { 378 excluded.union(newExcluded); 379 } else { 380 excluded = (GeneralSubtrees)newExcluded.clone(); 381 } 382 } 383 } 384 } 385 386 // Optional optimization: remove permitted subtrees that are excluded. 387 // This is not necessary for algorithm correctness, but it makes 388 // subsequent operations on the NameConstraints faster and require 389 // less space. 390 if (permitted != null) { 391 permitted.reduce(excluded); 392 } 393 394 // The NameConstraints have been changed, so re-encode them. Methods in 395 // this class assume that the encodings have already been done. 396 encodeThis(); 397 398 } 399 400 /** 401 * check whether a certificate conforms to these NameConstraints. 402 * This involves verifying that the subject name and subjectAltName 403 * extension (critical or noncritical) is consistent with the permitted 404 * subtrees state variables. Also verify that the subject name and 405 * subjectAltName extension (critical or noncritical) is consistent with 406 * the excluded subtrees state variables. 407 * 408 * @param cert X509Certificate to be verified 409 * @returns true if certificate verifies successfully 410 * @throws IOException on error 411 */ verify(X509Certificate cert)412 public boolean verify(X509Certificate cert) throws IOException { 413 414 if (cert == null) { 415 throw new IOException("Certificate is null"); 416 } 417 418 // Calculate hasMin and hasMax booleans (if necessary) 419 if (!minMaxValid) { 420 calcMinMax(); 421 } 422 423 if (hasMin) { 424 throw new IOException("Non-zero minimum BaseDistance in" 425 + " name constraints not supported"); 426 } 427 428 if (hasMax) { 429 throw new IOException("Maximum BaseDistance in" 430 + " name constraints not supported"); 431 } 432 433 X500Principal subjectPrincipal = cert.getSubjectX500Principal(); 434 X500Name subject = X500Name.asX500Name(subjectPrincipal); 435 436 if (subject.isEmpty() == false) { 437 if (verify(subject) == false) { 438 return false; 439 } 440 } 441 442 GeneralNames altNames = null; 443 // extract altNames 444 try { 445 // extract extensions, if any, from certInfo 446 // following returns null if certificate contains no extensions 447 X509CertImpl certImpl = X509CertImpl.toImpl(cert); 448 SubjectAlternativeNameExtension altNameExt = 449 certImpl.getSubjectAlternativeNameExtension(); 450 if (altNameExt != null) { 451 // extract altNames from extension; this call does not 452 // return an IOException on null altnames 453 altNames = altNameExt.get( 454 SubjectAlternativeNameExtension.SUBJECT_NAME); 455 } 456 } catch (CertificateException ce) { 457 throw new IOException("Unable to extract extensions from " + 458 "certificate: " + ce.getMessage()); 459 } 460 461 // If there are no subjectAlternativeNames, perform the special-case 462 // check where if the subjectName contains any EMAILADDRESS 463 // attributes, they must be checked against RFC822 constraints. 464 // If that passes, we're fine. 465 if (altNames == null) { 466 return verifyRFC822SpecialCase(subject); 467 } 468 469 // verify each subjectAltName 470 for (int i = 0; i < altNames.size(); i++) { 471 GeneralNameInterface altGNI = altNames.get(i).getName(); 472 if (!verify(altGNI)) { 473 return false; 474 } 475 } 476 477 // All tests passed. 478 return true; 479 } 480 481 /** 482 * check whether a name conforms to these NameConstraints. 483 * This involves verifying that the name is consistent with the 484 * permitted and excluded subtrees variables. 485 * 486 * @param name GeneralNameInterface name to be verified 487 * @returns true if certificate verifies successfully 488 * @throws IOException on error 489 */ verify(GeneralNameInterface name)490 public boolean verify(GeneralNameInterface name) throws IOException { 491 if (name == null) { 492 throw new IOException("name is null"); 493 } 494 495 // Verify that the name is consistent with the excluded subtrees 496 if (excluded != null && excluded.size() > 0) { 497 498 for (int i = 0; i < excluded.size(); i++) { 499 GeneralSubtree gs = excluded.get(i); 500 if (gs == null) 501 continue; 502 GeneralName gn = gs.getName(); 503 if (gn == null) 504 continue; 505 GeneralNameInterface exName = gn.getName(); 506 if (exName == null) 507 continue; 508 509 // if name matches or narrows any excluded subtree, 510 // return false 511 switch (exName.constrains(name)) { 512 case GeneralNameInterface.NAME_DIFF_TYPE: 513 case GeneralNameInterface.NAME_WIDENS: // name widens excluded 514 case GeneralNameInterface.NAME_SAME_TYPE: 515 break; 516 case GeneralNameInterface.NAME_MATCH: 517 case GeneralNameInterface.NAME_NARROWS: // subject name excluded 518 return false; 519 } 520 } 521 } 522 523 // Verify that the name is consistent with the permitted subtrees 524 if (permitted != null && permitted.size() > 0) { 525 526 boolean sameType = false; 527 528 for (int i = 0; i < permitted.size(); i++) { 529 GeneralSubtree gs = permitted.get(i); 530 if (gs == null) 531 continue; 532 GeneralName gn = gs.getName(); 533 if (gn == null) 534 continue; 535 GeneralNameInterface perName = gn.getName(); 536 if (perName == null) 537 continue; 538 539 // if Name matches any type in permitted, 540 // and Name does not match or narrow some permitted subtree, 541 // return false 542 switch (perName.constrains(name)) { 543 case GeneralNameInterface.NAME_DIFF_TYPE: 544 continue; // continue checking other permitted names 545 case GeneralNameInterface.NAME_WIDENS: // name widens permitted 546 case GeneralNameInterface.NAME_SAME_TYPE: 547 sameType = true; 548 continue; // continue to look for a match or narrow 549 case GeneralNameInterface.NAME_MATCH: 550 case GeneralNameInterface.NAME_NARROWS: 551 // name narrows permitted 552 return true; // name is definitely OK, so break out of loop 553 } 554 } 555 if (sameType) { 556 return false; 557 } 558 } 559 return true; 560 } 561 562 /** 563 * Perform the RFC 822 special case check. We have a certificate 564 * that does not contain any subject alternative names. Check that 565 * any EMAILADDRESS attributes in its subject name conform to these 566 * NameConstraints. 567 * 568 * @param subject the certificate's subject name 569 * @returns true if certificate verifies successfully 570 * @throws IOException on error 571 */ verifyRFC822SpecialCase(X500Name subject)572 public boolean verifyRFC822SpecialCase(X500Name subject) throws IOException { 573 for (AVA ava : subject.allAvas()) { 574 ObjectIdentifier attrOID = ava.getObjectIdentifier(); 575 if (attrOID.equals((Object)PKCS9Attribute.EMAIL_ADDRESS_OID)) { 576 String attrValue = ava.getValueString(); 577 if (attrValue != null) { 578 RFC822Name emailName; 579 try { 580 emailName = new RFC822Name(attrValue); 581 } catch (IOException ioe) { 582 continue; 583 } 584 if (!verify(emailName)) { 585 return(false); 586 } 587 } 588 } 589 } 590 return true; 591 } 592 593 /** 594 * Clone all objects that may be modified during certificate validation. 595 */ clone()596 public Object clone() { 597 try { 598 NameConstraintsExtension newNCE = 599 (NameConstraintsExtension) super.clone(); 600 601 if (permitted != null) { 602 newNCE.permitted = (GeneralSubtrees) permitted.clone(); 603 } 604 if (excluded != null) { 605 newNCE.excluded = (GeneralSubtrees) excluded.clone(); 606 } 607 return newNCE; 608 } catch (CloneNotSupportedException cnsee) { 609 throw new RuntimeException("CloneNotSupportedException while " + 610 "cloning NameConstraintsException. This should never happen."); 611 } 612 } 613 } 614