src/edu/internet2/middleware/shibboleth/common/provider/ShibbolethTrust.java

   1 /*
   2  * Copyright [2005] [University Corporation for Advanced Internet Development, Inc.]
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package edu.internet2.middleware.shibboleth.common.provider;
  18
  19 import java.io.ByteArrayInputStream;
  20 import java.io.IOException;
  21 import java.security.GeneralSecurityException;
  22 import java.security.cert.CertPathBuilder;
  23 import java.security.cert.CertPathValidator;
  24 import java.security.cert.CertPathValidatorException;
  25 import java.security.cert.CertStore;
  26 import java.security.cert.CertificateFactory;
  27 import java.security.cert.CertificateParsingException;
  28 import java.security.cert.CollectionCertStoreParameters;
  29 import java.security.cert.PKIXBuilderParameters;
  30 import java.security.cert.PKIXCertPathBuilderResult;
  31 import java.security.cert.PKIXCertPathValidatorResult;
  32 import java.security.cert.TrustAnchor;
  33 import java.security.cert.X509CRL;
  34 import java.security.cert.X509CertSelector;
  35 import java.security.cert.X509Certificate;
  36 import java.util.ArrayList;
  37 import java.util.Arrays;
  38 import java.util.Collection;
  39 import java.util.HashSet;
  40 import java.util.Iterator;
  41 import java.util.List;
  42 import java.util.Set;
  43
  44 import javax.security.auth.x500.X500Principal;
  45
  46 import org.apache.log4j.Logger;
  47 import org.apache.xml.security.exceptions.XMLSecurityException;
  48 import org.apache.xml.security.keys.KeyInfo;
  49 import org.apache.xml.security.keys.content.KeyName;
  50 import org.apache.xml.security.keys.content.X509Data;
  51 import org.apache.xml.security.keys.content.x509.XMLX509CRL;
  52 import org.apache.xml.security.keys.content.x509.XMLX509Certificate;
  53 import org.bouncycastle.asn1.ASN1InputStream;
  54 import org.bouncycastle.asn1.DERObject;
  55 import org.bouncycastle.asn1.DERObjectIdentifier;
  56 import org.bouncycastle.asn1.DERSequence;
  57 import org.bouncycastle.asn1.DERSet;
  58 import org.bouncycastle.asn1.DERString;
  59 import org.opensaml.SAMLException;
  60 import org.opensaml.SAMLSignedObject;
  61
  62 import edu.internet2.middleware.shibboleth.common.Trust;
  63 import edu.internet2.middleware.shibboleth.metadata.EntitiesDescriptor;
  64 import edu.internet2.middleware.shibboleth.metadata.EntityDescriptor;
  65 import edu.internet2.middleware.shibboleth.metadata.ExtendedEntitiesDescriptor;
  66 import edu.internet2.middleware.shibboleth.metadata.ExtendedEntityDescriptor;
  67 import edu.internet2.middleware.shibboleth.metadata.KeyAuthority;
  68 import edu.internet2.middleware.shibboleth.metadata.KeyDescriptor;
  69 import edu.internet2.middleware.shibboleth.metadata.RoleDescriptor;
  70
  71 /**
  72  * <code>Trust</code> implementation that does PKIX validation against key authorities included in shibboleth-specific
  73  * extensions to SAML 2 metadata.
  74  *
  75  * @author Walter Hoehn
  76  */
  77 public class ShibbolethTrust extends BasicTrust implements Trust {
  78
  79         private static Logger log = Logger.getLogger(ShibbolethTrust.class.getName());
  80         private static final String CN_OID = "2.5.4.3";
  81
  82         /*
  83          * @see edu.internet2.middleware.shibboleth.common.Trust#validate(java.security.cert.X509Certificate,
  84          *      java.security.cert.X509Certificate[], edu.internet2.middleware.shibboleth.metadata.RoleDescriptor)
  85          */
  86         public boolean validate(X509Certificate certificateEE, X509Certificate[] certificateChain, RoleDescriptor descriptor) {
  87
  88                 return validate(certificateEE, certificateChain, descriptor, true);
  89         }
  90
  91         /*
  92          * @see edu.internet2.middleware.shibboleth.common.Trust#validate(org.opensaml.SAMLSignedObject,
  93          *      edu.internet2.middleware.shibboleth.metadata.RoleDescriptor)
  94          */
  95         public boolean validate(SAMLSignedObject token, RoleDescriptor descriptor) {
  96
  97                 if (super.validate(token, descriptor)) return true;
  98
  99                 /* Certificates supplied with the signed object */
 100                 ArrayList/* <X509Certificate> */certificates = new ArrayList/* <X509Certificate> */();
 101                 X509Certificate certificateEE = null;
 102
 103                 /* Iterate to count the certificates, and look for the signer */
 104                 Iterator icertificates;
 105                 try {
 106                         icertificates = token.getX509Certificates();
 107                 } catch (SAMLException e1) {
 108                         return false;
 109                 }
 110                 while (icertificates.hasNext()) {
 111                         X509Certificate certificate = (X509Certificate) icertificates.next();
 112                         try {
 113                                 token.verify(certificate);
 114                                 // This is the certificate that signed the object
 115                                 certificateEE = certificate;
 116                                 certificates.add(certificate);
 117                         } catch (SAMLException e) {
 118                                 certificates.add(certificate);
 119                         }
 120                 }
 121
 122                 if (certificateEE == null) return false; // No key validates the signature
 123
 124                 // With a count we can now build a typed array
 125                 X509Certificate[] certificateChain = new X509Certificate[certificates.size()];
 126                 int i = 0;
 127                 for (icertificates = certificates.iterator(); icertificates.hasNext();) {
 128                         certificateChain[i++] = (X509Certificate) icertificates.next();
 129                 }
 130                 return validate(certificateEE, certificateChain, descriptor);
 131         }
 132
 133         /*
 134          * @see edu.internet2.middleware.shibboleth.common.Trust#validate(java.security.cert.X509Certificate,
 135          *      java.security.cert.X509Certificate[], edu.internet2.middleware.shibboleth.metadata.RoleDescriptor, boolean)
 136          */
 137         public boolean validate(X509Certificate certificateEE, X509Certificate[] certificateChain,
 138                         RoleDescriptor descriptor, boolean checkName) {
 139
 140                 // If we can successfully validate with an inline key, that's fine
 141                 boolean defaultValidation = super.validate(certificateEE, certificateChain, descriptor, checkName);
 142                 if (defaultValidation == true) { return true; }
 143
 144                 // Make sure we have the data we need
 145                 if (descriptor == null || certificateEE == null) {
 146                         log.error("Appropriate data was not supplied for trust evaluation.");
 147                         return false;
 148                 }
 149                 log.debug("Inline validation was unsuccessful.  Attmping PKIX...");
 150                 // If not, try PKIX validation against the shib-custom metadata extensions
 151
 152                 // First, we want to see if we can match a keyName from the metadata against the cert
 153                 // Iterator through all the keys in the metadata
 154                 if (checkName) {
 155
 156                         if (matchProviderId(certificateChain[0], descriptor.getEntityDescriptor().getId())) {
 157                                 checkName = false;
 158                         } else {
 159
 160                                 Iterator keyDescriptors = descriptor.getKeyDescriptors();
 161                                 while (checkName && keyDescriptors.hasNext()) {
 162                                         // Look for a key descriptor with the right usage bits
 163                                         KeyDescriptor keyDescriptor = (KeyDescriptor) keyDescriptors.next();
 164                                         if (keyDescriptor.getUse() == KeyDescriptor.ENCRYPTION) {
 165                                                 log.debug("Skipping key descriptor with inappropriate usage indicator.");
 166                                                 continue;
 167                                         }
 168
 169                                         // We found one, see if we can match the metadata's keyName against the cert
 170                                         KeyInfo keyInfo = keyDescriptor.getKeyInfo();
 171                                         if (keyInfo.containsKeyName()) {
 172                                                 for (int i = 0; i < keyInfo.lengthKeyName(); i++) {
 173                                                         try {
 174                                                                 if (matchKeyName(certificateChain[0], keyInfo.itemKeyName(i))) {
 175                                                                         checkName = false;
 176                                                                         break;
 177                                                                 }
 178                                                         } catch (XMLSecurityException e) {
 179                                                                 log.error("Problem retrieving key name from metadata: " + e);
 180                                                         }
 181                                                 }
 182                                         }
 183                                 }
 184                         }
 185                 }
 186
 187                 if (checkName) {
 188                         log.error("cannot match certificate subject against acceptable key names based on the "
 189                                         + "metadata entityId or KeyDescriptors");
 190                         return false;
 191                 }
 192
 193                 if (pkixValidate(certificateEE, certificateChain, descriptor.getEntityDescriptor())) { return true; }
 194                 return false;
 195         }
 196
 197         private boolean pkixValidate(X509Certificate certEE, X509Certificate[] certChain, EntityDescriptor entity) {
 198
 199                 if (entity instanceof ExtendedEntityDescriptor) {
 200                         Iterator keyAuthorities = ((ExtendedEntityDescriptor) entity).getKeyAuthorities();
 201                         // if we have any key authorities, construct a flat list of trust anchors representing each and attempt to
 202                         // validate against them in turn
 203                         while (keyAuthorities.hasNext()) {
 204                                 if (pkixValidate(certEE, certChain, (KeyAuthority) keyAuthorities.next())) { return true; }
 205                         }
 206                 }
 207
 208                 // We couldn't do path validation based on metadata attached to the entity, we now need to walk up the chain of
 209                 // nested entities and attempt to validate at each group level
 210                 EntitiesDescriptor group = entity.getEntitiesDescriptor();
 211                 if (group != null) {
 212                         if (pkixValidate(certEE, certChain, group)) { return true; }
 213                 }
 214
 215                 // We've walked the entire metadata chain with no success, so fail
 216                 return false;
 217         }
 218
 219         private boolean pkixValidate(X509Certificate certEE, X509Certificate[] certChain, EntitiesDescriptor group) {
 220
 221                 log.debug("Attemping to validate against parent group.");
 222                 if (group instanceof ExtendedEntitiesDescriptor) {
 223                         Iterator keyAuthorities = ((ExtendedEntitiesDescriptor) group).getKeyAuthorities();
 224                         // if we have any key authorities, construct a flat list of trust anchors representing each and attempt to
 225                         // validate against them in turn
 226                         while (keyAuthorities.hasNext()) {
 227                                 if (pkixValidate(certEE, certChain, (KeyAuthority) keyAuthorities.next())) { return true; }
 228                         }
 229                 }
 230
 231                 // If not, attempt to walk up the chain for validation
 232                 EntitiesDescriptor parent = group.getEntitiesDescriptor();
 233                 if (parent != null) {
 234                         if (pkixValidate(certEE, certChain, parent)) { return true; }
 235                 }
 236
 237                 return false;
 238         }
 239
 240         private boolean pkixValidate(X509Certificate certEE, X509Certificate[] certChain, KeyAuthority authority) {
 241
 242                 Set anchors = new HashSet();
 243                 Set crls = new HashSet();
 244                 Iterator keyInfos = authority.getKeyInfos();
 245                 while (keyInfos.hasNext()) {
 246                         KeyInfo keyInfo = (KeyInfo) keyInfos.next();
 247                         if (keyInfo.containsX509Data()) {
 248                                 try {
 249                                         // Add all certificates in the authority as trust anchors
 250                                         for (int i = 0; i < keyInfo.lengthX509Data(); i++) {
 251                                                 X509Data data = keyInfo.itemX509Data(i);
 252                                                 if (data.containsCertificate()) {
 253                                                         for (int j = 0; j < data.lengthCertificate(); j++) {
 254                                                                 XMLX509Certificate xmlCert = data.itemCertificate(j);
 255                                                                 anchors.add(new TrustAnchor(xmlCert.getX509Certificate(), null));
 256                                                         }
 257                                                 }
 258                                                 // Compile all CRLs in the authority
 259                                                 if (data.containsCRL()) {
 260                                                         for (int j = 0; j < data.lengthCRL(); j++) {
 261                                                                 XMLX509CRL xmlCrl = data.itemCRL(j);
 262                                                                 try {
 263                                                                         X509CRL crl = (X509CRL) CertificateFactory.getInstance("X.509").generateCRL(
 264                                                                                         new ByteArrayInputStream(xmlCrl.getCRLBytes()));
 265                                                                         if (crl.getRevokedCertificates() != null && crl.getRevokedCertificates().size() > 0) {
 266                                                                                 crls.add(crl);
 267                                                                         }
 268                                                                 } catch (GeneralSecurityException e) {
 269                                                                         log.error("Encountered an error parsing CRL from shibboleth metadata: " + e);
 270                                                                 }
 271                                                         }
 272                                                 }
 273                                         }
 274
 275                                 } catch (XMLSecurityException e) {
 276                                         log.error("Encountered an error constructing trust list from shibboleth metadata: " + e);
 277                                 }
 278                         }
 279                 }
 280
 281                 // alright, if we were able to create a trust list, attempt a pkix validation against the list
 282                 if (anchors.size() > 0) {
 283                         log.debug("Constructed a trust list from key authority.  Attempting path validation...");
 284                         try {
 285                                 CertPathValidator validator = CertPathValidator.getInstance("PKIX");
 286
 287                                 X509CertSelector selector = new X509CertSelector();
 288                                 selector.setCertificate(certEE);
 289                                 PKIXBuilderParameters params = new PKIXBuilderParameters(anchors, selector);
 290                                 params.setMaxPathLength(authority.getVerifyDepth());
 291                                 List storeMaterial = new ArrayList(crls);
 292                                 storeMaterial.addAll(Arrays.asList(certChain));
 293                                 CertStore store = CertStore.getInstance("Collection", new CollectionCertStoreParameters(storeMaterial));
 294                                 List stores = new ArrayList();
 295                                 stores.add(store);
 296                                 params.setCertStores(stores);
 297                                 if (crls.size() > 0) {
 298                                         params.setRevocationEnabled(true);
 299                                 } else {
 300                                         params.setRevocationEnabled(false);
 301                                 }
 302                                 // System.err.println(params.toString());
 303                                 CertPathBuilder builder = CertPathBuilder.getInstance("PKIX");
 304                                 PKIXCertPathBuilderResult buildResult = (PKIXCertPathBuilderResult) builder.build(params);
 305
 306                                 PKIXCertPathValidatorResult result = (PKIXCertPathValidatorResult) validator.validate(buildResult
 307                                                 .getCertPath(), params);
 308                                 log.debug("Path successfully validated.");
 309                                 return true;
 310
 311                         } catch (CertPathValidatorException e) {
 312                                 log.debug("Path failed to validate: " + e);
 313                         } catch (GeneralSecurityException e) {
 314                                 log.error("Encountered an error during validation: " + e);
 315                         }
 316                 }
 317                 return false;
 318         }
 319
 320         private static boolean matchKeyName(X509Certificate certificate, KeyName keyName) {
 321
 322                 // First, try to match DN against metadata
 323                 try {
 324                         if (certificate.getSubjectX500Principal().getName(X500Principal.RFC2253).equals(
 325                                         new X500Principal(keyName.getKeyName()).getName(X500Principal.RFC2253))) {
 326                                 log.debug("Matched against DN.");
 327                                 return true;
 328                         }
 329                 } catch (IllegalArgumentException iae) {
 330                         // squelch this runtime exception, since
 331                         // this might be a valid case
 332                 }
 333
 334                 // If that doesn't work, we try matching against
 335                 // some Subject Alt Names
 336                 try {
 337                         Collection altNames = certificate.getSubjectAlternativeNames();
 338                         if (altNames != null) {
 339                                 for (Iterator nameIterator = altNames.iterator(); nameIterator.hasNext();) {
 340                                         List altName = (List) nameIterator.next();
 341                                         if (altName.get(0).equals(new Integer(2)) || altName.get(0).equals(new Integer(6))) {
 342                                                 // 2 is DNS, 6 is URI
 343                                                 if (altName.get(0).equals(keyName.getKeyName())) {
 344                                                         log.debug("Matched against SubjectAltName.");
 345                                                         return true;
 346                                                 }
 347                                         }
 348                                 }
 349                         }
 350                 } catch (CertificateParsingException e1) {
 351                         log.error("Encountered an problem trying to extract Subject Alternate "
 352                                         + "Name from supplied certificate: " + e1);
 353                 }
 354
 355                 // If that doesn't work, try to match using
 356                 // SSL-style hostname matching
 357                 if (getHostNameFromDN(certificate.getSubjectX500Principal()).equals(keyName.getKeyName())) {
 358                         log.debug("Matched against hostname.");
 359                         return true;
 360                 }
 361
 362                 return false;
 363         }
 364
 365         private static boolean matchProviderId(X509Certificate certificate, String id) {
 366
 367                 // Try matching against URI Subject Alt Names
 368                 try {
 369                         Collection altNames = certificate.getSubjectAlternativeNames();
 370                         if (altNames != null) {
 371                                 for (Iterator nameIterator = altNames.iterator(); nameIterator.hasNext();) {
 372                                         List altName = (List) nameIterator.next();
 373                                         if (altName.get(0).equals(new Integer(6))) { // 6 is URI
 374                                                 if (altName.get(0).equals(id)) {
 375                                                         log.debug("Entity ID matched against SubjectAltName.");
 376                                                         return true;
 377                                                 }
 378                                         }
 379                                 }
 380                         }
 381                 } catch (CertificateParsingException e1) {
 382                         log.error("Encountered an problem trying to extract Subject Alternate "
 383                                         + "Name from supplied certificate: " + e1);
 384                 }
 385
 386                 // If that doesn't work, try to match using
 387                 // SSL-style hostname matching
 388                 if (getHostNameFromDN(certificate.getSubjectX500Principal()).equals(id)) {
 389                         log.debug("Entity ID matched against hostname.");
 390                         return true;
 391                 }
 392
 393                 return false;
 394         }
 395
 396         public static String getHostNameFromDN(X500Principal dn) {
 397
 398                 // Parse the ASN.1 representation of the dn and grab the last CN component that we find
 399                 // We used to do this with the dn string, but the JDK's default parsing caused problems with some DNs
 400                 try {
 401                         ASN1InputStream asn1Stream = new ASN1InputStream(dn.getEncoded());
 402                         DERObject parent = asn1Stream.readObject();
 403
 404                         if (!(parent instanceof DERSequence)) {
 405                                 log.error("Unable to extract host name name from certificate subject DN: incorrect ASN.1 encoding.");
 406                                 return null;
 407                         }
 408
 409                         String cn = null;
 410                         for (int i = 0; i < ((DERSequence) parent).size(); i++) {
 411                                 DERObject dnComponent = ((DERSequence) parent).getObjectAt(i).getDERObject();
 412                                 if (!(dnComponent instanceof DERSet)) {
 413                                         log.debug("No DN components.");
 414                                         continue;
 415                                 }
 416
 417                                 // Each DN component is a set
 418                                 for (int j = 0; j < ((DERSet) dnComponent).size(); j++) {
 419                                         DERObject grandChild = ((DERSet) dnComponent).getObjectAt(j).getDERObject();
 420
 421                                         if (((DERSequence) grandChild).getObjectAt(0) != null
 422                                                         && ((DERSequence) grandChild).getObjectAt(0).getDERObject() instanceof DERObjectIdentifier) {
 423                                                 DERObjectIdentifier componentId = (DERObjectIdentifier) ((DERSequence) grandChild).getObjectAt(
 424                                                                 0).getDERObject();
 425
 426                                                 if (CN_OID.equals(componentId.getId())) {
 427                                                         // OK, this dn component is actually a cn attribute
 428                                                         if (((DERSequence) grandChild).getObjectAt(1) != null
 429                                                                         && ((DERSequence) grandChild).getObjectAt(1).getDERObject() instanceof DERString) {
 430                                                                 cn = ((DERString) ((DERSequence) grandChild).getObjectAt(1).getDERObject()).getString();
 431                                                         }
 432                                                 }
 433                                         }
 434                                 }
 435                         }
 436                         asn1Stream.close();
 437                         return cn;
 438
 439                 } catch (IOException e) {
 440                         log.error("Unable to extract host name name from certificate subject DN: ASN.1 parsing failed: " + e);
 441                         return null;
 442                 }
 443         }
 444
 445 }