net/cert/cert_verify_proc_nss.cc

   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 #include "net/cert/cert_verify_proc_nss.h"
   6
   7 #include <string>
   8 #include <vector>
   9
  10 #include <cert.h>
  11 #include <nss.h>
  12 #include <prerror.h>
  13 #include <secerr.h>
  14 #include <sechash.h>
  15 #include <sslerr.h>
  16
  17 #include "base/logging.h"
  18 #include "crypto/nss_util.h"
  19 #include "crypto/scoped_nss_types.h"
  20 #include "crypto/sha2.h"
  21 #include "net/base/net_errors.h"
  22 #include "net/cert/asn1_util.h"
  23 #include "net/cert/cert_status_flags.h"
  24 #include "net/cert/cert_verifier.h"
  25 #include "net/cert/cert_verify_result.h"
  26 #include "net/cert/crl_set.h"
  27 #include "net/cert/ev_root_ca_metadata.h"
  28 #include "net/cert/x509_certificate.h"
  29 #include "net/cert/x509_util_nss.h"
  30
  31 #if defined(OS_IOS)
  32 #include <CommonCrypto/CommonDigest.h>
  33 #include "net/cert/x509_util_ios.h"
  34 #endif  // defined(OS_IOS)
  35
  36 namespace net {
  37
  38 namespace {
  39
  40 typedef scoped_ptr_malloc<
  41     CERTCertificatePolicies,
  42     crypto::NSSDestroyer<CERTCertificatePolicies,
  43                          CERT_DestroyCertificatePoliciesExtension> >
  44     ScopedCERTCertificatePolicies;
  45
  46 typedef scoped_ptr_malloc<
  47     CERTCertList,
  48     crypto::NSSDestroyer<CERTCertList, CERT_DestroyCertList> >
  49     ScopedCERTCertList;
  50
  51 // ScopedCERTValOutParam manages destruction of values in the CERTValOutParam
  52 // array that cvout points to.  cvout must be initialized as passed to
  53 // CERT_PKIXVerifyCert, so that the array must be terminated with
  54 // cert_po_end type.
  55 // When it goes out of scope, it destroys values of cert_po_trustAnchor
  56 // and cert_po_certList types, but doesn't release the array itself.
  57 class ScopedCERTValOutParam {
  58  public:
  59   explicit ScopedCERTValOutParam(CERTValOutParam* cvout) : cvout_(cvout) {}
  60
  61   ~ScopedCERTValOutParam() {
  62     Clear();
  63   }
  64
  65   // Free the internal resources, but do not release the array itself.
  66   void Clear() {
  67     if (cvout_ == NULL)
  68       return;
  69     for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
  70       switch (p->type) {
  71         case cert_po_trustAnchor:
  72           if (p->value.pointer.cert) {
  73             CERT_DestroyCertificate(p->value.pointer.cert);
  74             p->value.pointer.cert = NULL;
  75           }
  76           break;
  77         case cert_po_certList:
  78           if (p->value.pointer.chain) {
  79             CERT_DestroyCertList(p->value.pointer.chain);
  80             p->value.pointer.chain = NULL;
  81           }
  82           break;
  83         default:
  84           break;
  85       }
  86     }
  87   }
  88
  89  private:
  90   CERTValOutParam* cvout_;
  91
  92   DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
  93 };
  94
  95 // Map PORT_GetError() return values to our network error codes.
  96 int MapSecurityError(int err) {
  97   switch (err) {
  98     case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
  99       return ERR_NAME_NOT_RESOLVED;
 100     case SEC_ERROR_INVALID_ARGS:
 101       return ERR_INVALID_ARGUMENT;
 102     case SSL_ERROR_BAD_CERT_DOMAIN:
 103       return ERR_CERT_COMMON_NAME_INVALID;
 104     case SEC_ERROR_INVALID_TIME:
 105     case SEC_ERROR_EXPIRED_CERTIFICATE:
 106     case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
 107       return ERR_CERT_DATE_INVALID;
 108     case SEC_ERROR_UNKNOWN_ISSUER:
 109     case SEC_ERROR_UNTRUSTED_ISSUER:
 110     case SEC_ERROR_CA_CERT_INVALID:
 111       return ERR_CERT_AUTHORITY_INVALID;
 112     // TODO(port): map ERR_CERT_NO_REVOCATION_MECHANISM.
 113     case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
 114     case SEC_ERROR_OCSP_SERVER_ERROR:
 115       return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
 116     case SEC_ERROR_REVOKED_CERTIFICATE:
 117     case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
 118       return ERR_CERT_REVOKED;
 119     case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
 120       return ERR_CERT_NAME_CONSTRAINT_VIOLATION;
 121     case SEC_ERROR_BAD_DER:
 122     case SEC_ERROR_BAD_SIGNATURE:
 123     case SEC_ERROR_CERT_NOT_VALID:
 124     // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
 125     case SEC_ERROR_CERT_USAGES_INVALID:
 126     case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
 127     case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
 128                                           // the certificate is a CA.
 129     case SEC_ERROR_POLICY_VALIDATION_FAILED:
 130     case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
 131     case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
 132     case SEC_ERROR_EXTENSION_VALUE_INVALID:
 133       return ERR_CERT_INVALID;
 134     case SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED:
 135       return ERR_CERT_WEAK_SIGNATURE_ALGORITHM;
 136     default:
 137       LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
 138       return ERR_FAILED;
 139   }
 140 }
 141
 142 // Map PORT_GetError() return values to our cert status flags.
 143 CertStatus MapCertErrorToCertStatus(int err) {
 144   int net_error = MapSecurityError(err);
 145   return MapNetErrorToCertStatus(net_error);
 146 }
 147
 148 // Saves some information about the certificate chain cert_list in
 149 // *verify_result.  The caller MUST initialize *verify_result before calling
 150 // this function.
 151 // Note that cert_list[0] is the end entity certificate.
 152 void GetCertChainInfo(CERTCertList* cert_list,
 153                       CERTCertificate* root_cert,
 154                       CertVerifyResult* verify_result) {
 155   DCHECK(cert_list);
 156
 157   CERTCertificate* verified_cert = NULL;
 158   std::vector<CERTCertificate*> verified_chain;
 159   int i = 0;
 160   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 161        !CERT_LIST_END(node, cert_list);
 162        node = CERT_LIST_NEXT(node), ++i) {
 163     if (i == 0) {
 164       verified_cert = node->cert;
 165     } else {
 166       // Because of an NSS bug, CERT_PKIXVerifyCert may chain a self-signed
 167       // certificate of a root CA to another certificate of the same root CA
 168       // key.  Detect that error and ignore the root CA certificate.
 169       // See https://bugzilla.mozilla.org/show_bug.cgi?id=721288.
 170       if (node->cert->isRoot) {
 171         // NOTE: isRoot doesn't mean the certificate is a trust anchor.  It
 172         // means the certificate is self-signed.  Here we assume isRoot only
 173         // implies the certificate is self-issued.
 174         CERTCertListNode* next_node = CERT_LIST_NEXT(node);
 175         CERTCertificate* next_cert;
 176         if (!CERT_LIST_END(next_node, cert_list)) {
 177           next_cert = next_node->cert;
 178         } else {
 179           next_cert = root_cert;
 180         }
 181         // Test that |node->cert| is actually a self-signed certificate
 182         // whose key is equal to |next_cert|, and not a self-issued
 183         // certificate signed by another key of the same CA.
 184         if (next_cert && SECITEM_ItemsAreEqual(&node->cert->derPublicKey,
 185                                                &next_cert->derPublicKey)) {
 186           continue;
 187         }
 188       }
 189       verified_chain.push_back(node->cert);
 190     }
 191
 192     SECAlgorithmID& signature = node->cert->signature;
 193     SECOidTag oid_tag = SECOID_FindOIDTag(&signature.algorithm);
 194     switch (oid_tag) {
 195       case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
 196         verify_result->has_md5 = true;
 197         break;
 198       case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
 199         verify_result->has_md2 = true;
 200         break;
 201       case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
 202         verify_result->has_md4 = true;
 203         break;
 204       default:
 205         break;
 206     }
 207   }
 208
 209   if (root_cert)
 210     verified_chain.push_back(root_cert);
 211 #if defined(OS_IOS)
 212   verify_result->verified_cert =
 213       x509_util_ios::CreateCertFromNSSHandles(verified_cert, verified_chain);
 214 #else
 215   verify_result->verified_cert =
 216       X509Certificate::CreateFromHandle(verified_cert, verified_chain);
 217 #endif  // defined(OS_IOS)
 218 }
 219
 220 // IsKnownRoot returns true if the given certificate is one that we believe
 221 // is a standard (as opposed to user-installed) root.
 222 bool IsKnownRoot(CERTCertificate* root) {
 223   if (!root || !root->slot)
 224     return false;
 225
 226   // This magic name is taken from
 227   // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
 228   return 0 == strcmp(PK11_GetSlotName(root->slot),
 229                      "NSS Builtin Objects");
 230 }
 231
 232 // Returns true if the given certificate is one of the additional trust anchors.
 233 bool IsAdditionalTrustAnchor(CERTCertList* additional_trust_anchors,
 234                              CERTCertificate* root) {
 235   if (!additional_trust_anchors || !root)
 236     return false;
 237   for (CERTCertListNode* node = CERT_LIST_HEAD(additional_trust_anchors);
 238        !CERT_LIST_END(node, additional_trust_anchors);
 239        node = CERT_LIST_NEXT(node)) {
 240     if (CERT_CompareCerts(node->cert, root))
 241       return true;
 242   }
 243   return false;
 244 }
 245
 246 enum CRLSetResult {
 247   kCRLSetOk,
 248   kCRLSetRevoked,
 249   kCRLSetUnknown,
 250 };
 251
 252 // CheckRevocationWithCRLSet attempts to check each element of |cert_list|
 253 // against |crl_set|. It returns:
 254 //   kCRLSetRevoked: if any element of the chain is known to have been revoked.
 255 //   kCRLSetUnknown: if there is no fresh information about some element in
 256 //       the chain.
 257 //   kCRLSetOk: if every element in the chain is covered by a fresh CRLSet and
 258 //       is unrevoked.
 259 CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
 260                                        CERTCertificate* root,
 261                                        CRLSet* crl_set) {
 262   std::vector<CERTCertificate*> certs;
 263
 264   if (cert_list) {
 265     for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 266          !CERT_LIST_END(node, cert_list);
 267          node = CERT_LIST_NEXT(node)) {
 268       certs.push_back(node->cert);
 269     }
 270   }
 271   if (root)
 272     certs.push_back(root);
 273
 274   bool covered = true;
 275
 276   // We iterate from the root certificate down to the leaf, keeping track of
 277   // the issuer's SPKI at each step.
 278   std::string issuer_spki_hash;
 279   for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
 280        i != certs.rend(); ++i) {
 281     CERTCertificate* cert = *i;
 282
 283     base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
 284                           cert->derCert.len);
 285
 286     base::StringPiece spki;
 287     if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
 288       NOTREACHED();
 289       covered = false;
 290       continue;
 291     }
 292     const std::string spki_hash = crypto::SHA256HashString(spki);
 293
 294     base::StringPiece serial_number = base::StringPiece(
 295         reinterpret_cast<char*>(cert->serialNumber.data),
 296         cert->serialNumber.len);
 297
 298     CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
 299
 300     if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
 301       result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
 302
 303     issuer_spki_hash = spki_hash;
 304
 305     switch (result) {
 306       case CRLSet::REVOKED:
 307         return kCRLSetRevoked;
 308       case CRLSet::UNKNOWN:
 309         covered = false;
 310         continue;
 311       case CRLSet::GOOD:
 312         continue;
 313       default:
 314         NOTREACHED();
 315         covered = false;
 316         continue;
 317     }
 318   }
 319
 320   if (!covered || crl_set->IsExpired())
 321     return kCRLSetUnknown;
 322   return kCRLSetOk;
 323 }
 324
 325 // Forward declarations.
 326 SECStatus RetryPKIXVerifyCertWithWorkarounds(
 327     CERTCertificate* cert_handle, int num_policy_oids,
 328     bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
 329     CERTValOutParam* cvout);
 330 SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
 331
 332 // Call CERT_PKIXVerifyCert for the cert_handle.
 333 // Verification results are stored in an array of CERTValOutParam.
 334 // If |hard_fail| is true, and no policy_oids are supplied (eg: EV is NOT being
 335 // checked), then the failure to obtain valid CRL/OCSP information for all
 336 // certificates that contain CRL/OCSP URLs will cause the certificate to be
 337 // treated as if it was revoked. Since failures may be caused by transient
 338 // network failures or by malicious attackers, in general, hard_fail should be
 339 // false.
 340 // If policy_oids is not NULL and num_policy_oids is positive, policies
 341 // are also checked.
 342 // additional_trust_anchors is an optional list of certificates that can be
 343 // trusted as anchors when building a certificate chain.
 344 // Caller must initialize cvout before calling this function.
 345 SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
 346                          bool check_revocation,
 347                          bool hard_fail,
 348                          bool cert_io_enabled,
 349                          const SECOidTag* policy_oids,
 350                          int num_policy_oids,
 351                          CERTCertList* additional_trust_anchors,
 352                          CERTValOutParam* cvout) {
 353   bool use_crl = check_revocation;
 354   bool use_ocsp = check_revocation;
 355
 356   PRUint64 revocation_method_flags =
 357       CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
 358       CERT_REV_M_ALLOW_NETWORK_FETCHING |
 359       CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
 360       CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
 361       CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
 362   PRUint64 revocation_method_independent_flags =
 363       CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
 364   if (check_revocation && policy_oids && num_policy_oids > 0) {
 365     // EV verification requires revocation checking.  Consider the certificate
 366     // revoked if we don't have revocation info.
 367     // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
 368     // verification or we want strict revocation flags.
 369     revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
 370     revocation_method_independent_flags |=
 371         CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
 372   } else if (check_revocation && hard_fail) {
 373     revocation_method_flags |= CERT_REV_M_FAIL_ON_MISSING_FRESH_INFO;
 374     revocation_method_independent_flags |=
 375         CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
 376   } else {
 377     revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
 378     revocation_method_independent_flags |=
 379         CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
 380   }
 381   PRUint64 method_flags[2];
 382   method_flags[cert_revocation_method_crl] = revocation_method_flags;
 383   method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
 384
 385   if (use_crl) {
 386     method_flags[cert_revocation_method_crl] |=
 387         CERT_REV_M_TEST_USING_THIS_METHOD;
 388   }
 389   if (use_ocsp) {
 390     method_flags[cert_revocation_method_ocsp] |=
 391         CERT_REV_M_TEST_USING_THIS_METHOD;
 392   }
 393
 394   CERTRevocationMethodIndex preferred_revocation_methods[1];
 395   if (use_ocsp) {
 396     preferred_revocation_methods[0] = cert_revocation_method_ocsp;
 397   } else {
 398     preferred_revocation_methods[0] = cert_revocation_method_crl;
 399   }
 400
 401   CERTRevocationFlags revocation_flags;
 402   revocation_flags.leafTests.number_of_defined_methods =
 403       arraysize(method_flags);
 404   revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
 405   revocation_flags.leafTests.number_of_preferred_methods =
 406       arraysize(preferred_revocation_methods);
 407   revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
 408   revocation_flags.leafTests.cert_rev_method_independent_flags =
 409       revocation_method_independent_flags;
 410
 411   revocation_flags.chainTests.number_of_defined_methods =
 412       arraysize(method_flags);
 413   revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
 414   revocation_flags.chainTests.number_of_preferred_methods =
 415       arraysize(preferred_revocation_methods);
 416   revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
 417   revocation_flags.chainTests.cert_rev_method_independent_flags =
 418       revocation_method_independent_flags;
 419
 420
 421   std::vector<CERTValInParam> cvin;
 422   cvin.reserve(7);
 423   CERTValInParam in_param;
 424   in_param.type = cert_pi_revocationFlags;
 425   in_param.value.pointer.revocation = &revocation_flags;
 426   cvin.push_back(in_param);
 427   if (policy_oids && num_policy_oids > 0) {
 428     in_param.type = cert_pi_policyOID;
 429     in_param.value.arraySize = num_policy_oids;
 430     in_param.value.array.oids = policy_oids;
 431     cvin.push_back(in_param);
 432   }
 433   if (additional_trust_anchors) {
 434     in_param.type = cert_pi_trustAnchors;
 435     in_param.value.pointer.chain = additional_trust_anchors;
 436     cvin.push_back(in_param);
 437     in_param.type = cert_pi_useOnlyTrustAnchors;
 438     in_param.value.scalar.b = PR_FALSE;
 439     cvin.push_back(in_param);
 440   }
 441   in_param.type = cert_pi_end;
 442   cvin.push_back(in_param);
 443
 444   SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 445                                      &cvin[0], cvout, NULL);
 446   if (rv != SECSuccess) {
 447     rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
 448                                             cert_io_enabled, &cvin, cvout);
 449   }
 450   return rv;
 451 }
 452
 453 // PKIXVerifyCert calls this function to work around some bugs in
 454 // CERT_PKIXVerifyCert.  All the arguments of this function are either the
 455 // arguments or local variables of PKIXVerifyCert.
 456 SECStatus RetryPKIXVerifyCertWithWorkarounds(
 457     CERTCertificate* cert_handle, int num_policy_oids,
 458     bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
 459     CERTValOutParam* cvout) {
 460   // We call this function when the first CERT_PKIXVerifyCert call in
 461   // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
 462   SECStatus rv = SECFailure;
 463   int nss_error = PORT_GetError();
 464   CERTValInParam in_param;
 465
 466   // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
 467   // CA certificate, so we retry with cert_pi_useAIACertFetch.
 468   // cert_pi_useAIACertFetch has several bugs in its error handling and
 469   // error reporting (NSS bug 528743), so we don't use it by default.
 470   // Note: When building a certificate chain, CERT_PKIXVerifyCert may
 471   // incorrectly pick a CA certificate with the same subject name as the
 472   // missing intermediate CA certificate, and  fail with the
 473   // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
 474   // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
 475   if (cert_io_enabled &&
 476       (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
 477        nss_error == SEC_ERROR_BAD_SIGNATURE)) {
 478     DCHECK_EQ(cvin->back().type,  cert_pi_end);
 479     cvin->pop_back();
 480     in_param.type = cert_pi_useAIACertFetch;
 481     in_param.value.scalar.b = PR_TRUE;
 482     cvin->push_back(in_param);
 483     in_param.type = cert_pi_end;
 484     cvin->push_back(in_param);
 485     rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 486                              &(*cvin)[0], cvout, NULL);
 487     if (rv == SECSuccess)
 488       return rv;
 489     int new_nss_error = PORT_GetError();
 490     if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
 491         new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
 492         new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
 493         new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
 494         new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
 495         !IS_SEC_ERROR(new_nss_error)) {
 496       // Use the original error code because of cert_pi_useAIACertFetch's
 497       // bad error reporting.
 498       PORT_SetError(nss_error);
 499       return rv;
 500     }
 501     nss_error = new_nss_error;
 502   }
 503
 504   // If an intermediate CA certificate has requireExplicitPolicy in its
 505   // policyConstraints extension, CERT_PKIXVerifyCert fails with
 506   // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
 507   // certificate policy (NSS bug 552775).  So we retry with the certificate
 508   // policy found in the server certificate.
 509   if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
 510       num_policy_oids == 0) {
 511     SECOidTag policy = GetFirstCertPolicy(cert_handle);
 512     if (policy != SEC_OID_UNKNOWN) {
 513       DCHECK_EQ(cvin->back().type,  cert_pi_end);
 514       cvin->pop_back();
 515       in_param.type = cert_pi_policyOID;
 516       in_param.value.arraySize = 1;
 517       in_param.value.array.oids = &policy;
 518       cvin->push_back(in_param);
 519       in_param.type = cert_pi_end;
 520       cvin->push_back(in_param);
 521       rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 522                                &(*cvin)[0], cvout, NULL);
 523       if (rv != SECSuccess) {
 524         // Use the original error code.
 525         PORT_SetError(nss_error);
 526       }
 527     }
 528   }
 529
 530   return rv;
 531 }
 532
 533 // Decodes the certificatePolicies extension of the certificate.  Returns
 534 // NULL if the certificate doesn't have the extension or the extension can't
 535 // be decoded.  The returned value must be freed with a
 536 // CERT_DestroyCertificatePoliciesExtension call.
 537 CERTCertificatePolicies* DecodeCertPolicies(
 538     CERTCertificate* cert_handle) {
 539   SECItem policy_ext;
 540   SECStatus rv = CERT_FindCertExtension(cert_handle,
 541                                         SEC_OID_X509_CERTIFICATE_POLICIES,
 542                                         &policy_ext);
 543   if (rv != SECSuccess)
 544     return NULL;
 545   CERTCertificatePolicies* policies =
 546       CERT_DecodeCertificatePoliciesExtension(&policy_ext);
 547   SECITEM_FreeItem(&policy_ext, PR_FALSE);
 548   return policies;
 549 }
 550
 551 // Returns the OID tag for the first certificate policy in the certificate's
 552 // certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
 553 // has no certificate policy.
 554 SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
 555   ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
 556   if (!policies.get())
 557     return SEC_OID_UNKNOWN;
 558
 559   CERTPolicyInfo* policy_info = policies->policyInfos[0];
 560   if (!policy_info)
 561     return SEC_OID_UNKNOWN;
 562   if (policy_info->oid != SEC_OID_UNKNOWN)
 563     return policy_info->oid;
 564
 565   // The certificate policy is unknown to NSS.  We need to create a dynamic
 566   // OID tag for the policy.
 567   SECOidData od;
 568   od.oid.len = policy_info->policyID.len;
 569   od.oid.data = policy_info->policyID.data;
 570   od.offset = SEC_OID_UNKNOWN;
 571   // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
 572   // default description here.  The description doesn't need to be unique for
 573   // each OID.
 574   od.desc = "a certificate policy";
 575   od.mechanism = CKM_INVALID_MECHANISM;
 576   od.supportedExtension = INVALID_CERT_EXTENSION;
 577   return SECOID_AddEntry(&od);
 578 }
 579
 580 HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
 581   HashValue hash(HASH_VALUE_SHA1);
 582 #if defined(OS_IOS)
 583   CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
 584 #else
 585   SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
 586                               cert->derPublicKey.data, cert->derPublicKey.len);
 587   DCHECK_EQ(SECSuccess, rv);
 588 #endif
 589   return hash;
 590 }
 591
 592 HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
 593   HashValue hash(HASH_VALUE_SHA256);
 594 #if defined(OS_IOS)
 595   CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
 596 #else
 597   SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
 598                               cert->derPublicKey.data, cert->derPublicKey.len);
 599   DCHECK_EQ(rv, SECSuccess);
 600 #endif
 601   return hash;
 602 }
 603
 604 void AppendPublicKeyHashes(CERTCertList* cert_list,
 605                            CERTCertificate* root_cert,
 606                            HashValueVector* hashes) {
 607   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 608        !CERT_LIST_END(node, cert_list);
 609        node = CERT_LIST_NEXT(node)) {
 610     hashes->push_back(CertPublicKeyHashSHA1(node->cert));
 611     hashes->push_back(CertPublicKeyHashSHA256(node->cert));
 612   }
 613   if (root_cert) {
 614     hashes->push_back(CertPublicKeyHashSHA1(root_cert));
 615     hashes->push_back(CertPublicKeyHashSHA256(root_cert));
 616   }
 617 }
 618
 619 // Returns true if |cert_handle| contains a policy OID that is an EV policy
 620 // OID according to |metadata|, storing the resulting policy OID in
 621 // |*ev_policy_oid|. A true return is not sufficient to establish that a
 622 // certificate is EV, but a false return is sufficient to establish the
 623 // certificate cannot be EV.
 624 bool IsEVCandidate(EVRootCAMetadata* metadata,
 625                    CERTCertificate* cert_handle,
 626                    SECOidTag* ev_policy_oid) {
 627   DCHECK(cert_handle);
 628   ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
 629   if (!policies.get())
 630     return false;
 631
 632   CERTPolicyInfo** policy_infos = policies->policyInfos;
 633   while (*policy_infos != NULL) {
 634     CERTPolicyInfo* policy_info = *policy_infos++;
 635     // If the Policy OID is unknown, that implicitly means it has not been
 636     // registered as an EV policy.
 637     if (policy_info->oid == SEC_OID_UNKNOWN)
 638       continue;
 639     if (metadata->IsEVPolicyOID(policy_info->oid)) {
 640       *ev_policy_oid = policy_info->oid;
 641       return true;
 642     }
 643   }
 644
 645   return false;
 646 }
 647
 648 // Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
 649 // and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
 650 // TODO(wtc): A possible optimization is that we get the trust anchor from
 651 // the first PKIXVerifyCert call.  We look up the EV policy for the trust
 652 // anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
 653 // Otherwise, we pass just that EV policy (as opposed to all the EV policies)
 654 // to the second PKIXVerifyCert call.
 655 bool VerifyEV(CERTCertificate* cert_handle,
 656               int flags,
 657               CRLSet* crl_set,
 658               bool rev_checking_enabled,
 659               EVRootCAMetadata* metadata,
 660               SECOidTag ev_policy_oid,
 661               CERTCertList* additional_trust_anchors) {
 662   CERTValOutParam cvout[3];
 663   int cvout_index = 0;
 664   cvout[cvout_index].type = cert_po_certList;
 665   cvout[cvout_index].value.pointer.chain = NULL;
 666   int cvout_cert_list_index = cvout_index;
 667   cvout_index++;
 668   cvout[cvout_index].type = cert_po_trustAnchor;
 669   cvout[cvout_index].value.pointer.cert = NULL;
 670   int cvout_trust_anchor_index = cvout_index;
 671   cvout_index++;
 672   cvout[cvout_index].type = cert_po_end;
 673   ScopedCERTValOutParam scoped_cvout(cvout);
 674
 675   SECStatus status = PKIXVerifyCert(
 676       cert_handle,
 677       rev_checking_enabled,
 678       true, /* hard fail is implied in EV. */
 679       flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
 680       &ev_policy_oid,
 681       1,
 682       additional_trust_anchors,
 683       cvout);
 684   if (status != SECSuccess)
 685     return false;
 686
 687   CERTCertificate* root_ca =
 688       cvout[cvout_trust_anchor_index].value.pointer.cert;
 689   if (root_ca == NULL)
 690     return false;
 691
 692   // This second PKIXVerifyCert call could have found a different certification
 693   // path and one or more of the certificates on this new path, that weren't on
 694   // the old path, might have been revoked.
 695   if (crl_set) {
 696     CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
 697         cvout[cvout_cert_list_index].value.pointer.chain,
 698         cvout[cvout_trust_anchor_index].value.pointer.cert,
 699         crl_set);
 700     if (crl_set_result == kCRLSetRevoked)
 701       return false;
 702   }
 703
 704 #if defined(OS_IOS)
 705   SHA1HashValue fingerprint = x509_util_ios::CalculateFingerprintNSS(root_ca);
 706 #else
 707   SHA1HashValue fingerprint =
 708       X509Certificate::CalculateFingerprint(root_ca);
 709 #endif
 710   return metadata->HasEVPolicyOID(fingerprint, ev_policy_oid);
 711 }
 712
 713 CERTCertList* CertificateListToCERTCertList(const CertificateList& list) {
 714   CERTCertList* result = CERT_NewCertList();
 715   for (size_t i = 0; i < list.size(); ++i) {
 716 #if defined(OS_IOS)
 717     // X509Certificate::os_cert_handle() on iOS is a SecCertificateRef; convert
 718     // it to an NSS CERTCertificate.
 719     CERTCertificate* cert = x509_util_ios::CreateNSSCertHandleFromOSHandle(
 720         list[i]->os_cert_handle());
 721 #else
 722     CERTCertificate* cert = list[i]->os_cert_handle();
 723 #endif
 724     CERT_AddCertToListTail(result, CERT_DupCertificate(cert));
 725   }
 726   return result;
 727 }
 728
 729 }  // namespace
 730
 731 CertVerifyProcNSS::CertVerifyProcNSS() {}
 732
 733 CertVerifyProcNSS::~CertVerifyProcNSS() {}
 734
 735 bool CertVerifyProcNSS::SupportsAdditionalTrustAnchors() const {
 736   return true;
 737 }
 738
 739 int CertVerifyProcNSS::VerifyInternal(
 740     X509Certificate* cert,
 741     const std::string& hostname,
 742     int flags,
 743     CRLSet* crl_set,
 744     const CertificateList& additional_trust_anchors,
 745     CertVerifyResult* verify_result) {
 746 #if defined(OS_IOS)
 747   // For iOS, the entire chain must be loaded into NSS's in-memory certificate
 748   // store.
 749   x509_util_ios::NSSCertChain scoped_chain(cert);
 750   CERTCertificate* cert_handle = scoped_chain.cert_handle();
 751 #else
 752   CERTCertificate* cert_handle = cert->os_cert_handle();
 753 #endif  // defined(OS_IOS)
 754
 755   if (!cert->VerifyNameMatch(hostname,
 756                              &verify_result->common_name_fallback_used)) {
 757     verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
 758   }
 759
 760   // Make sure that the cert is valid now.
 761   SECCertTimeValidity validity = CERT_CheckCertValidTimes(
 762       cert_handle, PR_Now(), PR_TRUE);
 763   if (validity != secCertTimeValid)
 764     verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
 765
 766   CERTValOutParam cvout[3];
 767   int cvout_index = 0;
 768   cvout[cvout_index].type = cert_po_certList;
 769   cvout[cvout_index].value.pointer.chain = NULL;
 770   int cvout_cert_list_index = cvout_index;
 771   cvout_index++;
 772   cvout[cvout_index].type = cert_po_trustAnchor;
 773   cvout[cvout_index].value.pointer.cert = NULL;
 774   int cvout_trust_anchor_index = cvout_index;
 775   cvout_index++;
 776   cvout[cvout_index].type = cert_po_end;
 777   ScopedCERTValOutParam scoped_cvout(cvout);
 778
 779   EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
 780   SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
 781   bool is_ev_candidate =
 782       (flags & CertVerifier::VERIFY_EV_CERT) &&
 783       IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
 784   bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
 785   bool check_revocation =
 786       cert_io_enabled &&
 787       (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
 788   if (check_revocation)
 789     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 790
 791   ScopedCERTCertList trust_anchors;
 792   if (!additional_trust_anchors.empty()) {
 793     trust_anchors.reset(
 794         CertificateListToCERTCertList(additional_trust_anchors));
 795   }
 796
 797   SECStatus status = PKIXVerifyCert(cert_handle, check_revocation, false,
 798                                     cert_io_enabled, NULL, 0,
 799                                     trust_anchors.get(), cvout);
 800
 801   if (status == SECSuccess &&
 802       (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS) &&
 803       !IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert)) {
 804     // TODO(rsleevi): Optimize this by supplying the constructed chain to
 805     // libpkix via cvin. Omitting for now, due to lack of coverage in upstream
 806     // NSS tests for that feature.
 807     scoped_cvout.Clear();
 808     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 809     status = PKIXVerifyCert(cert_handle, true, true,
 810                             cert_io_enabled, NULL, 0, trust_anchors.get(),
 811                             cvout);
 812   }
 813
 814   if (status == SECSuccess) {
 815     AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
 816                           cvout[cvout_trust_anchor_index].value.pointer.cert,
 817                           &verify_result->public_key_hashes);
 818
 819     verify_result->is_issued_by_known_root =
 820         IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
 821     verify_result->is_issued_by_additional_trust_anchor =
 822         IsAdditionalTrustAnchor(
 823             trust_anchors.get(),
 824             cvout[cvout_trust_anchor_index].value.pointer.cert);
 825
 826     GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
 827                      cvout[cvout_trust_anchor_index].value.pointer.cert,
 828                      verify_result);
 829   }
 830
 831   CRLSetResult crl_set_result = kCRLSetUnknown;
 832   if (crl_set) {
 833     crl_set_result = CheckRevocationWithCRLSet(
 834         cvout[cvout_cert_list_index].value.pointer.chain,
 835         cvout[cvout_trust_anchor_index].value.pointer.cert,
 836         crl_set);
 837     if (crl_set_result == kCRLSetRevoked) {
 838       PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
 839       status = SECFailure;
 840     }
 841   }
 842
 843   if (status != SECSuccess) {
 844     int err = PORT_GetError();
 845     LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
 846                << " failed err=" << err;
 847     // CERT_PKIXVerifyCert rerports the wrong error code for
 848     // expired certificates (NSS bug 491174)
 849     if (err == SEC_ERROR_CERT_NOT_VALID &&
 850         (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
 851       err = SEC_ERROR_EXPIRED_CERTIFICATE;
 852     CertStatus cert_status = MapCertErrorToCertStatus(err);
 853     if (cert_status) {
 854       verify_result->cert_status |= cert_status;
 855       return MapCertStatusToNetError(verify_result->cert_status);
 856     }
 857     // |err| is not a certificate error.
 858     return MapSecurityError(err);
 859   }
 860
 861   if (IsCertStatusError(verify_result->cert_status))
 862     return MapCertStatusToNetError(verify_result->cert_status);
 863
 864   if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate) {
 865     check_revocation |=
 866         crl_set_result != kCRLSetOk &&
 867         cert_io_enabled &&
 868         (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
 869     if (check_revocation)
 870       verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 871
 872     if (VerifyEV(cert_handle, flags, crl_set, check_revocation, metadata,
 873                  ev_policy_oid, trust_anchors.get())) {
 874       verify_result->cert_status |= CERT_STATUS_IS_EV;
 875     }
 876   }
 877
 878   return OK;
 879 }
 880
 881 }  // namespace net