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 "build/build_config.h"
  19 #include "crypto/nss_util.h"
  20 #include "crypto/scoped_nss_types.h"
  21 #include "crypto/sha2.h"
  22 #include "net/base/net_errors.h"
  23 #include "net/cert/asn1_util.h"
  24 #include "net/cert/cert_status_flags.h"
  25 #include "net/cert/cert_verifier.h"
  26 #include "net/cert/cert_verify_result.h"
  27 #include "net/cert/crl_set.h"
  28 #include "net/cert/ev_root_ca_metadata.h"
  29 #include "net/cert/x509_certificate.h"
  30 #include "net/cert/x509_util_nss.h"
  31
  32 #if defined(OS_IOS)
  33 #include <CommonCrypto/CommonDigest.h>
  34 #include "net/cert/x509_util_ios.h"
  35 #endif  // defined(OS_IOS)
  36
  37 #if defined(USE_NSS_CERTS)
  38 #include <dlfcn.h>
  39 #else
  40 #include <ocsp.h>
  41 #endif
  42
  43 namespace net {
  44
  45 namespace {
  46
  47 typedef scoped_ptr<
  48     CERTCertificatePolicies,
  49     crypto::NSSDestroyer<CERTCertificatePolicies,
  50                          CERT_DestroyCertificatePoliciesExtension> >
  51     ScopedCERTCertificatePolicies;
  52
  53 typedef scoped_ptr<
  54     CERTCertList,
  55     crypto::NSSDestroyer<CERTCertList, CERT_DestroyCertList> >
  56     ScopedCERTCertList;
  57
  58 // ScopedCERTValOutParam manages destruction of values in the CERTValOutParam
  59 // array that cvout points to.  cvout must be initialized as passed to
  60 // CERT_PKIXVerifyCert, so that the array must be terminated with
  61 // cert_po_end type.
  62 // When it goes out of scope, it destroys values of cert_po_trustAnchor
  63 // and cert_po_certList types, but doesn't release the array itself.
  64 class ScopedCERTValOutParam {
  65  public:
  66   explicit ScopedCERTValOutParam(CERTValOutParam* cvout) : cvout_(cvout) {}
  67
  68   ~ScopedCERTValOutParam() {
  69     Clear();
  70   }
  71
  72   // Free the internal resources, but do not release the array itself.
  73   void Clear() {
  74     if (cvout_ == NULL)
  75       return;
  76     for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
  77       switch (p->type) {
  78         case cert_po_trustAnchor:
  79           if (p->value.pointer.cert) {
  80             CERT_DestroyCertificate(p->value.pointer.cert);
  81             p->value.pointer.cert = NULL;
  82           }
  83           break;
  84         case cert_po_certList:
  85           if (p->value.pointer.chain) {
  86             CERT_DestroyCertList(p->value.pointer.chain);
  87             p->value.pointer.chain = NULL;
  88           }
  89           break;
  90         default:
  91           break;
  92       }
  93     }
  94   }
  95
  96  private:
  97   CERTValOutParam* cvout_;
  98
  99   DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
 100 };
 101
 102 // Map PORT_GetError() return values to our network error codes.
 103 int MapSecurityError(int err) {
 104   switch (err) {
 105     case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
 106       return ERR_NAME_NOT_RESOLVED;
 107     case SEC_ERROR_INVALID_ARGS:
 108       return ERR_INVALID_ARGUMENT;
 109     case SSL_ERROR_BAD_CERT_DOMAIN:
 110       return ERR_CERT_COMMON_NAME_INVALID;
 111     case SEC_ERROR_INVALID_TIME:
 112     case SEC_ERROR_EXPIRED_CERTIFICATE:
 113     case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
 114       return ERR_CERT_DATE_INVALID;
 115     case SEC_ERROR_UNKNOWN_ISSUER:
 116     case SEC_ERROR_UNTRUSTED_ISSUER:
 117     case SEC_ERROR_CA_CERT_INVALID:
 118     case SEC_ERROR_APPLICATION_CALLBACK_ERROR:  // Rejected by
 119                                                 // chain_verify_callback.
 120       return ERR_CERT_AUTHORITY_INVALID;
 121     // TODO(port): map ERR_CERT_NO_REVOCATION_MECHANISM.
 122     case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
 123     case SEC_ERROR_OCSP_SERVER_ERROR:
 124       return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
 125     case SEC_ERROR_REVOKED_CERTIFICATE:
 126     case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
 127       return ERR_CERT_REVOKED;
 128     case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
 129       return ERR_CERT_NAME_CONSTRAINT_VIOLATION;
 130     case SEC_ERROR_BAD_DER:
 131     case SEC_ERROR_BAD_SIGNATURE:
 132     case SEC_ERROR_CERT_NOT_VALID:
 133     // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
 134     case SEC_ERROR_CERT_USAGES_INVALID:
 135     case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
 136     case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
 137                                           // the certificate is a CA.
 138     case SEC_ERROR_POLICY_VALIDATION_FAILED:
 139     case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
 140     case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
 141     case SEC_ERROR_EXTENSION_VALUE_INVALID:
 142       return ERR_CERT_INVALID;
 143     case SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED:
 144       return ERR_CERT_WEAK_SIGNATURE_ALGORITHM;
 145     default:
 146       LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
 147       return ERR_FAILED;
 148   }
 149 }
 150
 151 // Map PORT_GetError() return values to our cert status flags.
 152 CertStatus MapCertErrorToCertStatus(int err) {
 153   int net_error = MapSecurityError(err);
 154   return MapNetErrorToCertStatus(net_error);
 155 }
 156
 157 // Saves some information about the certificate chain cert_list in
 158 // *verify_result.  The caller MUST initialize *verify_result before calling
 159 // this function.
 160 // Note that cert_list[0] is the end entity certificate.
 161 void GetCertChainInfo(CERTCertList* cert_list,
 162                       CERTCertificate* root_cert,
 163                       CertVerifyResult* verify_result) {
 164   DCHECK(cert_list);
 165
 166   CERTCertificate* verified_cert = NULL;
 167   std::vector<CERTCertificate*> verified_chain;
 168   int i = 0;
 169   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 170        !CERT_LIST_END(node, cert_list);
 171        node = CERT_LIST_NEXT(node), ++i) {
 172     if (i == 0) {
 173       verified_cert = node->cert;
 174     } else {
 175       // Because of an NSS bug, CERT_PKIXVerifyCert may chain a self-signed
 176       // certificate of a root CA to another certificate of the same root CA
 177       // key.  Detect that error and ignore the root CA certificate.
 178       // See https://bugzilla.mozilla.org/show_bug.cgi?id=721288.
 179       if (node->cert->isRoot) {
 180         // NOTE: isRoot doesn't mean the certificate is a trust anchor.  It
 181         // means the certificate is self-signed.  Here we assume isRoot only
 182         // implies the certificate is self-issued.
 183         CERTCertListNode* next_node = CERT_LIST_NEXT(node);
 184         CERTCertificate* next_cert;
 185         if (!CERT_LIST_END(next_node, cert_list)) {
 186           next_cert = next_node->cert;
 187         } else {
 188           next_cert = root_cert;
 189         }
 190         // Test that |node->cert| is actually a self-signed certificate
 191         // whose key is equal to |next_cert|, and not a self-issued
 192         // certificate signed by another key of the same CA.
 193         if (next_cert && SECITEM_ItemsAreEqual(&node->cert->derPublicKey,
 194                                                &next_cert->derPublicKey)) {
 195           continue;
 196         }
 197       }
 198       verified_chain.push_back(node->cert);
 199     }
 200
 201     SECAlgorithmID& signature = node->cert->signature;
 202     SECOidTag oid_tag = SECOID_FindOIDTag(&signature.algorithm);
 203     switch (oid_tag) {
 204       case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
 205         verify_result->has_md5 = true;
 206         break;
 207       case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
 208         verify_result->has_md2 = true;
 209         break;
 210       case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
 211         verify_result->has_md4 = true;
 212         break;
 213       case SEC_OID_PKCS1_SHA1_WITH_RSA_ENCRYPTION:
 214       case SEC_OID_ISO_SHA1_WITH_RSA_SIGNATURE:
 215       case SEC_OID_ANSIX9_DSA_SIGNATURE_WITH_SHA1_DIGEST:
 216       case SEC_OID_ANSIX962_ECDSA_SHA1_SIGNATURE:
 217         verify_result->has_sha1 = true;
 218         break;
 219       default:
 220         break;
 221     }
 222   }
 223
 224   if (root_cert)
 225     verified_chain.push_back(root_cert);
 226 #if defined(OS_IOS)
 227   verify_result->verified_cert =
 228       x509_util_ios::CreateCertFromNSSHandles(verified_cert, verified_chain);
 229 #else
 230   verify_result->verified_cert =
 231       X509Certificate::CreateFromHandle(verified_cert, verified_chain);
 232 #endif  // defined(OS_IOS)
 233 }
 234
 235 // IsKnownRoot returns true if the given certificate is one that we believe
 236 // is a standard (as opposed to user-installed) root.
 237 bool IsKnownRoot(CERTCertificate* root) {
 238   if (!root || !root->slot)
 239     return false;
 240
 241   // This magic name is taken from
 242   // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
 243   return 0 == strcmp(PK11_GetSlotName(root->slot),
 244                      "NSS Builtin Objects");
 245 }
 246
 247 // Returns true if the given certificate is one of the additional trust anchors.
 248 bool IsAdditionalTrustAnchor(CERTCertList* additional_trust_anchors,
 249                              CERTCertificate* root) {
 250   if (!additional_trust_anchors || !root)
 251     return false;
 252   for (CERTCertListNode* node = CERT_LIST_HEAD(additional_trust_anchors);
 253        !CERT_LIST_END(node, additional_trust_anchors);
 254        node = CERT_LIST_NEXT(node)) {
 255     if (CERT_CompareCerts(node->cert, root))
 256       return true;
 257   }
 258   return false;
 259 }
 260
 261 enum CRLSetResult {
 262   kCRLSetOk,
 263   kCRLSetRevoked,
 264   kCRLSetUnknown,
 265 };
 266
 267 // CheckRevocationWithCRLSet attempts to check each element of |cert_list|
 268 // against |crl_set|. It returns:
 269 //   kCRLSetRevoked: if any element of the chain is known to have been revoked.
 270 //   kCRLSetUnknown: if there is no fresh information about the leaf
 271 //       certificate in the chain or if the CRLSet has expired.
 272 //
 273 //       Only the leaf certificate is considered for coverage because some
 274 //       intermediates have CRLs with no revocations (after filtering) and
 275 //       those CRLs are pruned from the CRLSet at generation time. This means
 276 //       that some EV sites would otherwise take the hit of an OCSP lookup for
 277 //       no reason.
 278 //   kCRLSetOk: otherwise.
 279 CRLSetResult CheckRevocationWithCRLSet(CERTCertList* cert_list,
 280                                        CERTCertificate* root,
 281                                        CRLSet* crl_set) {
 282   std::vector<CERTCertificate*> certs;
 283
 284   if (cert_list) {
 285     for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 286          !CERT_LIST_END(node, cert_list);
 287          node = CERT_LIST_NEXT(node)) {
 288       certs.push_back(node->cert);
 289     }
 290   }
 291   if (root)
 292     certs.push_back(root);
 293
 294   // error is set to true if any errors are found. It causes such chains to be
 295   // considered as not covered.
 296   bool error = false;
 297   // last_covered is set to the coverage state of the previous certificate. The
 298   // certificates are iterated over backwards thus, after the iteration,
 299   // |last_covered| contains the coverage state of the leaf certificate.
 300   bool last_covered = false;
 301
 302   // We iterate from the root certificate down to the leaf, keeping track of
 303   // the issuer's SPKI at each step.
 304   std::string issuer_spki_hash;
 305   for (std::vector<CERTCertificate*>::reverse_iterator i = certs.rbegin();
 306        i != certs.rend(); ++i) {
 307     CERTCertificate* cert = *i;
 308
 309     base::StringPiece der(reinterpret_cast<char*>(cert->derCert.data),
 310                           cert->derCert.len);
 311
 312     base::StringPiece spki;
 313     if (!asn1::ExtractSPKIFromDERCert(der, &spki)) {
 314       NOTREACHED();
 315       error = true;
 316       continue;
 317     }
 318     const std::string spki_hash = crypto::SHA256HashString(spki);
 319
 320     base::StringPiece serial_number = base::StringPiece(
 321         reinterpret_cast<char*>(cert->serialNumber.data),
 322         cert->serialNumber.len);
 323
 324     CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
 325
 326     if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
 327       result = crl_set->CheckSerial(serial_number, issuer_spki_hash);
 328
 329     issuer_spki_hash = spki_hash;
 330
 331     switch (result) {
 332       case CRLSet::REVOKED:
 333         return kCRLSetRevoked;
 334       case CRLSet::UNKNOWN:
 335         last_covered = false;
 336         continue;
 337       case CRLSet::GOOD:
 338         last_covered = true;
 339         continue;
 340       default:
 341         NOTREACHED();
 342         error = true;
 343         continue;
 344     }
 345   }
 346
 347   if (error || !last_covered || crl_set->IsExpired())
 348     return kCRLSetUnknown;
 349   return kCRLSetOk;
 350 }
 351
 352 // Forward declarations.
 353 SECStatus RetryPKIXVerifyCertWithWorkarounds(
 354     CERTCertificate* cert_handle, int num_policy_oids,
 355     bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
 356     CERTValOutParam* cvout);
 357 SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle);
 358
 359 // Call CERT_PKIXVerifyCert for the cert_handle.
 360 // Verification results are stored in an array of CERTValOutParam.
 361 // If |hard_fail| is true, and no policy_oids are supplied (eg: EV is NOT being
 362 // checked), then the failure to obtain valid CRL/OCSP information for all
 363 // certificates that contain CRL/OCSP URLs will cause the certificate to be
 364 // treated as if it was revoked. Since failures may be caused by transient
 365 // network failures or by malicious attackers, in general, hard_fail should be
 366 // false.
 367 // If policy_oids is not NULL and num_policy_oids is positive, policies
 368 // are also checked.
 369 // additional_trust_anchors is an optional list of certificates that can be
 370 // trusted as anchors when building a certificate chain.
 371 // Caller must initialize cvout before calling this function.
 372 SECStatus PKIXVerifyCert(CERTCertificate* cert_handle,
 373                          bool check_revocation,
 374                          bool hard_fail,
 375                          bool cert_io_enabled,
 376                          const SECOidTag* policy_oids,
 377                          int num_policy_oids,
 378                          CERTCertList* additional_trust_anchors,
 379                          CERTChainVerifyCallback* chain_verify_callback,
 380                          CERTValOutParam* cvout) {
 381   bool use_crl = check_revocation;
 382   bool use_ocsp = check_revocation;
 383
 384   PRUint64 revocation_method_flags =
 385       CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
 386       CERT_REV_M_ALLOW_NETWORK_FETCHING |
 387       CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
 388       CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
 389       CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
 390   PRUint64 revocation_method_independent_flags =
 391       CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
 392   if (check_revocation && policy_oids && num_policy_oids > 0) {
 393     // EV verification requires revocation checking.  Consider the certificate
 394     // revoked if we don't have revocation info.
 395     // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
 396     // verification or we want strict revocation flags.
 397     revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
 398     revocation_method_independent_flags |=
 399         CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
 400   } else if (check_revocation && hard_fail) {
 401     revocation_method_flags |= CERT_REV_M_FAIL_ON_MISSING_FRESH_INFO;
 402     revocation_method_independent_flags |=
 403         CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
 404   } else {
 405     revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
 406     revocation_method_independent_flags |=
 407         CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
 408   }
 409   PRUint64 method_flags[2];
 410   method_flags[cert_revocation_method_crl] = revocation_method_flags;
 411   method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
 412
 413   if (use_crl) {
 414     method_flags[cert_revocation_method_crl] |=
 415         CERT_REV_M_TEST_USING_THIS_METHOD;
 416   }
 417   if (use_ocsp) {
 418     method_flags[cert_revocation_method_ocsp] |=
 419         CERT_REV_M_TEST_USING_THIS_METHOD;
 420   }
 421
 422   CERTRevocationMethodIndex preferred_revocation_methods[1];
 423   if (use_ocsp) {
 424     preferred_revocation_methods[0] = cert_revocation_method_ocsp;
 425   } else {
 426     preferred_revocation_methods[0] = cert_revocation_method_crl;
 427   }
 428
 429   CERTRevocationFlags revocation_flags;
 430   revocation_flags.leafTests.number_of_defined_methods =
 431       arraysize(method_flags);
 432   revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
 433   revocation_flags.leafTests.number_of_preferred_methods =
 434       arraysize(preferred_revocation_methods);
 435   revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
 436   revocation_flags.leafTests.cert_rev_method_independent_flags =
 437       revocation_method_independent_flags;
 438
 439   revocation_flags.chainTests.number_of_defined_methods =
 440       arraysize(method_flags);
 441   revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
 442   revocation_flags.chainTests.number_of_preferred_methods =
 443       arraysize(preferred_revocation_methods);
 444   revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
 445   revocation_flags.chainTests.cert_rev_method_independent_flags =
 446       revocation_method_independent_flags;
 447
 448
 449   std::vector<CERTValInParam> cvin;
 450   cvin.reserve(7);
 451   CERTValInParam in_param;
 452   in_param.type = cert_pi_revocationFlags;
 453   in_param.value.pointer.revocation = &revocation_flags;
 454   cvin.push_back(in_param);
 455   if (policy_oids && num_policy_oids > 0) {
 456     in_param.type = cert_pi_policyOID;
 457     in_param.value.arraySize = num_policy_oids;
 458     in_param.value.array.oids = policy_oids;
 459     cvin.push_back(in_param);
 460   }
 461   if (additional_trust_anchors) {
 462     in_param.type = cert_pi_trustAnchors;
 463     in_param.value.pointer.chain = additional_trust_anchors;
 464     cvin.push_back(in_param);
 465     in_param.type = cert_pi_useOnlyTrustAnchors;
 466     in_param.value.scalar.b = PR_FALSE;
 467     cvin.push_back(in_param);
 468   }
 469   if (chain_verify_callback) {
 470     in_param.type = cert_pi_chainVerifyCallback;
 471     in_param.value.pointer.chainVerifyCallback = chain_verify_callback;
 472     cvin.push_back(in_param);
 473   }
 474   in_param.type = cert_pi_end;
 475   cvin.push_back(in_param);
 476
 477   SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 478                                      &cvin[0], cvout, NULL);
 479   if (rv != SECSuccess) {
 480     rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
 481                                             cert_io_enabled, &cvin, cvout);
 482   }
 483   return rv;
 484 }
 485
 486 // PKIXVerifyCert calls this function to work around some bugs in
 487 // CERT_PKIXVerifyCert.  All the arguments of this function are either the
 488 // arguments or local variables of PKIXVerifyCert.
 489 SECStatus RetryPKIXVerifyCertWithWorkarounds(
 490     CERTCertificate* cert_handle, int num_policy_oids,
 491     bool cert_io_enabled, std::vector<CERTValInParam>* cvin,
 492     CERTValOutParam* cvout) {
 493   // We call this function when the first CERT_PKIXVerifyCert call in
 494   // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
 495   SECStatus rv = SECFailure;
 496   int nss_error = PORT_GetError();
 497   CERTValInParam in_param;
 498
 499   // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
 500   // CA certificate, so we retry with cert_pi_useAIACertFetch.
 501   // cert_pi_useAIACertFetch has several bugs in its error handling and
 502   // error reporting (NSS bug 528743), so we don't use it by default.
 503   // Note: When building a certificate chain, CERT_PKIXVerifyCert may
 504   // incorrectly pick a CA certificate with the same subject name as the
 505   // missing intermediate CA certificate, and  fail with the
 506   // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
 507   // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
 508   if (cert_io_enabled &&
 509       (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
 510        nss_error == SEC_ERROR_BAD_SIGNATURE)) {
 511     DCHECK_EQ(cvin->back().type,  cert_pi_end);
 512     cvin->pop_back();
 513     in_param.type = cert_pi_useAIACertFetch;
 514     in_param.value.scalar.b = PR_TRUE;
 515     cvin->push_back(in_param);
 516     in_param.type = cert_pi_end;
 517     cvin->push_back(in_param);
 518     rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 519                              &(*cvin)[0], cvout, NULL);
 520     if (rv == SECSuccess)
 521       return rv;
 522     int new_nss_error = PORT_GetError();
 523     if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
 524         new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
 525         new_nss_error == SEC_ERROR_BAD_INFO_ACCESS_LOCATION ||
 526         new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
 527         new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
 528         !IS_SEC_ERROR(new_nss_error)) {
 529       // Use the original error code because of cert_pi_useAIACertFetch's
 530       // bad error reporting.
 531       PORT_SetError(nss_error);
 532       return rv;
 533     }
 534     nss_error = new_nss_error;
 535   }
 536
 537   // If an intermediate CA certificate has requireExplicitPolicy in its
 538   // policyConstraints extension, CERT_PKIXVerifyCert fails with
 539   // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
 540   // certificate policy (NSS bug 552775).  So we retry with the certificate
 541   // policy found in the server certificate.
 542   if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
 543       num_policy_oids == 0) {
 544     SECOidTag policy = GetFirstCertPolicy(cert_handle);
 545     if (policy != SEC_OID_UNKNOWN) {
 546       DCHECK_EQ(cvin->back().type,  cert_pi_end);
 547       cvin->pop_back();
 548       in_param.type = cert_pi_policyOID;
 549       in_param.value.arraySize = 1;
 550       in_param.value.array.oids = &policy;
 551       cvin->push_back(in_param);
 552       in_param.type = cert_pi_end;
 553       cvin->push_back(in_param);
 554       rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
 555                                &(*cvin)[0], cvout, NULL);
 556       if (rv != SECSuccess) {
 557         // Use the original error code.
 558         PORT_SetError(nss_error);
 559       }
 560     }
 561   }
 562
 563   return rv;
 564 }
 565
 566 // Decodes the certificatePolicies extension of the certificate.  Returns
 567 // NULL if the certificate doesn't have the extension or the extension can't
 568 // be decoded.  The returned value must be freed with a
 569 // CERT_DestroyCertificatePoliciesExtension call.
 570 CERTCertificatePolicies* DecodeCertPolicies(
 571     CERTCertificate* cert_handle) {
 572   SECItem policy_ext;
 573   SECStatus rv = CERT_FindCertExtension(cert_handle,
 574                                         SEC_OID_X509_CERTIFICATE_POLICIES,
 575                                         &policy_ext);
 576   if (rv != SECSuccess)
 577     return NULL;
 578   CERTCertificatePolicies* policies =
 579       CERT_DecodeCertificatePoliciesExtension(&policy_ext);
 580   SECITEM_FreeItem(&policy_ext, PR_FALSE);
 581   return policies;
 582 }
 583
 584 // Returns the OID tag for the first certificate policy in the certificate's
 585 // certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
 586 // has no certificate policy.
 587 SECOidTag GetFirstCertPolicy(CERTCertificate* cert_handle) {
 588   ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
 589   if (!policies.get())
 590     return SEC_OID_UNKNOWN;
 591
 592   CERTPolicyInfo* policy_info = policies->policyInfos[0];
 593   if (!policy_info)
 594     return SEC_OID_UNKNOWN;
 595   if (policy_info->oid != SEC_OID_UNKNOWN)
 596     return policy_info->oid;
 597
 598   // The certificate policy is unknown to NSS.  We need to create a dynamic
 599   // OID tag for the policy.
 600   SECOidData od;
 601   od.oid.len = policy_info->policyID.len;
 602   od.oid.data = policy_info->policyID.data;
 603   od.offset = SEC_OID_UNKNOWN;
 604   // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
 605   // default description here.  The description doesn't need to be unique for
 606   // each OID.
 607   od.desc = "a certificate policy";
 608   od.mechanism = CKM_INVALID_MECHANISM;
 609   od.supportedExtension = INVALID_CERT_EXTENSION;
 610   return SECOID_AddEntry(&od);
 611 }
 612
 613 HashValue CertPublicKeyHashSHA1(CERTCertificate* cert) {
 614   HashValue hash(HASH_VALUE_SHA1);
 615 #if defined(OS_IOS)
 616   CC_SHA1(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
 617 #else
 618   SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data(),
 619                               cert->derPublicKey.data, cert->derPublicKey.len);
 620   DCHECK_EQ(SECSuccess, rv);
 621 #endif
 622   return hash;
 623 }
 624
 625 HashValue CertPublicKeyHashSHA256(CERTCertificate* cert) {
 626   HashValue hash(HASH_VALUE_SHA256);
 627 #if defined(OS_IOS)
 628   CC_SHA256(cert->derPublicKey.data, cert->derPublicKey.len, hash.data());
 629 #else
 630   SECStatus rv = HASH_HashBuf(HASH_AlgSHA256, hash.data(),
 631                               cert->derPublicKey.data, cert->derPublicKey.len);
 632   DCHECK_EQ(rv, SECSuccess);
 633 #endif
 634   return hash;
 635 }
 636
 637 void AppendPublicKeyHashes(CERTCertList* cert_list,
 638                            CERTCertificate* root_cert,
 639                            HashValueVector* hashes) {
 640   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
 641        !CERT_LIST_END(node, cert_list);
 642        node = CERT_LIST_NEXT(node)) {
 643     hashes->push_back(CertPublicKeyHashSHA1(node->cert));
 644     hashes->push_back(CertPublicKeyHashSHA256(node->cert));
 645   }
 646   if (root_cert) {
 647     hashes->push_back(CertPublicKeyHashSHA1(root_cert));
 648     hashes->push_back(CertPublicKeyHashSHA256(root_cert));
 649   }
 650 }
 651
 652 // Returns true if |cert_handle| contains a policy OID that is an EV policy
 653 // OID according to |metadata|, storing the resulting policy OID in
 654 // |*ev_policy_oid|. A true return is not sufficient to establish that a
 655 // certificate is EV, but a false return is sufficient to establish the
 656 // certificate cannot be EV.
 657 bool IsEVCandidate(EVRootCAMetadata* metadata,
 658                    CERTCertificate* cert_handle,
 659                    SECOidTag* ev_policy_oid) {
 660   DCHECK(cert_handle);
 661   ScopedCERTCertificatePolicies policies(DecodeCertPolicies(cert_handle));
 662   if (!policies.get())
 663     return false;
 664
 665   CERTPolicyInfo** policy_infos = policies->policyInfos;
 666   while (*policy_infos != NULL) {
 667     CERTPolicyInfo* policy_info = *policy_infos++;
 668     // If the Policy OID is unknown, that implicitly means it has not been
 669     // registered as an EV policy.
 670     if (policy_info->oid == SEC_OID_UNKNOWN)
 671       continue;
 672     if (metadata->IsEVPolicyOID(policy_info->oid)) {
 673       *ev_policy_oid = policy_info->oid;
 674       return true;
 675     }
 676   }
 677
 678   return false;
 679 }
 680
 681 // Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
 682 // and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
 683 // TODO(wtc): A possible optimization is that we get the trust anchor from
 684 // the first PKIXVerifyCert call.  We look up the EV policy for the trust
 685 // anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
 686 // Otherwise, we pass just that EV policy (as opposed to all the EV policies)
 687 // to the second PKIXVerifyCert call.
 688 bool VerifyEV(CERTCertificate* cert_handle,
 689               int flags,
 690               CRLSet* crl_set,
 691               bool rev_checking_enabled,
 692               EVRootCAMetadata* metadata,
 693               SECOidTag ev_policy_oid,
 694               CERTCertList* additional_trust_anchors,
 695               CERTChainVerifyCallback* chain_verify_callback) {
 696   CERTValOutParam cvout[3];
 697   int cvout_index = 0;
 698   cvout[cvout_index].type = cert_po_certList;
 699   cvout[cvout_index].value.pointer.chain = NULL;
 700   int cvout_cert_list_index = cvout_index;
 701   cvout_index++;
 702   cvout[cvout_index].type = cert_po_trustAnchor;
 703   cvout[cvout_index].value.pointer.cert = NULL;
 704   int cvout_trust_anchor_index = cvout_index;
 705   cvout_index++;
 706   cvout[cvout_index].type = cert_po_end;
 707   ScopedCERTValOutParam scoped_cvout(cvout);
 708
 709   SECStatus status = PKIXVerifyCert(
 710       cert_handle,
 711       rev_checking_enabled,
 712       true, /* hard fail is implied in EV. */
 713       flags & CertVerifier::VERIFY_CERT_IO_ENABLED,
 714       &ev_policy_oid,
 715       1,
 716       additional_trust_anchors,
 717       chain_verify_callback,
 718       cvout);
 719   if (status != SECSuccess)
 720     return false;
 721
 722   CERTCertificate* root_ca =
 723       cvout[cvout_trust_anchor_index].value.pointer.cert;
 724   if (root_ca == NULL)
 725     return false;
 726
 727   // This second PKIXVerifyCert call could have found a different certification
 728   // path and one or more of the certificates on this new path, that weren't on
 729   // the old path, might have been revoked.
 730   if (crl_set) {
 731     CRLSetResult crl_set_result = CheckRevocationWithCRLSet(
 732         cvout[cvout_cert_list_index].value.pointer.chain,
 733         cvout[cvout_trust_anchor_index].value.pointer.cert,
 734         crl_set);
 735     if (crl_set_result == kCRLSetRevoked)
 736       return false;
 737   }
 738
 739 #if defined(OS_IOS)
 740   SHA1HashValue fingerprint = x509_util_ios::CalculateFingerprintNSS(root_ca);
 741 #else
 742   SHA1HashValue fingerprint =
 743       X509Certificate::CalculateFingerprint(root_ca);
 744 #endif
 745   return metadata->HasEVPolicyOID(fingerprint, ev_policy_oid);
 746 }
 747
 748 CERTCertList* CertificateListToCERTCertList(const CertificateList& list) {
 749   CERTCertList* result = CERT_NewCertList();
 750   for (size_t i = 0; i < list.size(); ++i) {
 751 #if defined(OS_IOS)
 752     // X509Certificate::os_cert_handle() on iOS is a SecCertificateRef; convert
 753     // it to an NSS CERTCertificate.
 754     CERTCertificate* cert = x509_util_ios::CreateNSSCertHandleFromOSHandle(
 755         list[i]->os_cert_handle());
 756 #else
 757     CERTCertificate* cert = list[i]->os_cert_handle();
 758 #endif
 759     CERT_AddCertToListTail(result, CERT_DupCertificate(cert));
 760   }
 761   return result;
 762 }
 763
 764 }  // namespace
 765
 766 CertVerifyProcNSS::CertVerifyProcNSS()
 767 #if defined(USE_NSS_CERTS)
 768     : cache_ocsp_response_from_side_channel_(
 769           reinterpret_cast<CacheOCSPResponseFromSideChannelFunction>(
 770               dlsym(RTLD_DEFAULT, "CERT_CacheOCSPResponseFromSideChannel")))
 771 #else
 772     : cache_ocsp_response_from_side_channel_(
 773           &CERT_CacheOCSPResponseFromSideChannel)
 774 #endif
 775 {
 776 }
 777
 778 CertVerifyProcNSS::~CertVerifyProcNSS() {}
 779
 780 bool CertVerifyProcNSS::SupportsAdditionalTrustAnchors() const {
 781   return true;
 782 }
 783
 784 bool CertVerifyProcNSS::SupportsOCSPStapling() const {
 785   return cache_ocsp_response_from_side_channel_;
 786 }
 787
 788 int CertVerifyProcNSS::VerifyInternalImpl(
 789     X509Certificate* cert,
 790     const std::string& hostname,
 791     const std::string& ocsp_response,
 792     int flags,
 793     CRLSet* crl_set,
 794     const CertificateList& additional_trust_anchors,
 795     CERTChainVerifyCallback* chain_verify_callback,
 796     CertVerifyResult* verify_result) {
 797 #if defined(OS_IOS)
 798   // For iOS, the entire chain must be loaded into NSS's in-memory certificate
 799   // store.
 800   x509_util_ios::NSSCertChain scoped_chain(cert);
 801   CERTCertificate* cert_handle = scoped_chain.cert_handle();
 802 #else
 803   CERTCertificate* cert_handle = cert->os_cert_handle();
 804 #endif  // defined(OS_IOS)
 805
 806   if (!ocsp_response.empty() && cache_ocsp_response_from_side_channel_) {
 807     // Note: NSS uses a thread-safe global hash table, so this call will
 808     // affect any concurrent verification operations on |cert| or copies of
 809     // the same certificate. This is an unavoidable limitation of NSS's OCSP
 810     // API.
 811     SECItem ocsp_response_item;
 812     ocsp_response_item.data = reinterpret_cast<unsigned char*>(
 813         const_cast<char*>(ocsp_response.data()));
 814     ocsp_response_item.len = ocsp_response.size();
 815     cache_ocsp_response_from_side_channel_(CERT_GetDefaultCertDB(), cert_handle,
 816                                            PR_Now(), &ocsp_response_item,
 817                                            nullptr);
 818   }
 819
 820   if (!cert->VerifyNameMatch(hostname,
 821                              &verify_result->common_name_fallback_used)) {
 822     verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
 823   }
 824
 825   // Make sure that the cert is valid now.
 826   SECCertTimeValidity validity = CERT_CheckCertValidTimes(
 827       cert_handle, PR_Now(), PR_TRUE);
 828   if (validity != secCertTimeValid)
 829     verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
 830
 831   CERTValOutParam cvout[3];
 832   int cvout_index = 0;
 833   cvout[cvout_index].type = cert_po_certList;
 834   cvout[cvout_index].value.pointer.chain = NULL;
 835   int cvout_cert_list_index = cvout_index;
 836   cvout_index++;
 837   cvout[cvout_index].type = cert_po_trustAnchor;
 838   cvout[cvout_index].value.pointer.cert = NULL;
 839   int cvout_trust_anchor_index = cvout_index;
 840   cvout_index++;
 841   cvout[cvout_index].type = cert_po_end;
 842   ScopedCERTValOutParam scoped_cvout(cvout);
 843
 844   EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
 845   SECOidTag ev_policy_oid = SEC_OID_UNKNOWN;
 846   bool is_ev_candidate =
 847       (flags & CertVerifier::VERIFY_EV_CERT) &&
 848       IsEVCandidate(metadata, cert_handle, &ev_policy_oid);
 849   bool cert_io_enabled = flags & CertVerifier::VERIFY_CERT_IO_ENABLED;
 850   bool check_revocation =
 851       cert_io_enabled &&
 852       (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
 853   if (check_revocation)
 854     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 855
 856   ScopedCERTCertList trust_anchors;
 857   if (!additional_trust_anchors.empty()) {
 858     trust_anchors.reset(
 859         CertificateListToCERTCertList(additional_trust_anchors));
 860   }
 861
 862   SECStatus status = PKIXVerifyCert(cert_handle,
 863                                     check_revocation,
 864                                     false,
 865                                     cert_io_enabled,
 866                                     NULL,
 867                                     0,
 868                                     trust_anchors.get(),
 869                                     chain_verify_callback,
 870                                     cvout);
 871
 872   if (status == SECSuccess &&
 873       (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS) &&
 874       !IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert)) {
 875     // TODO(rsleevi): Optimize this by supplying the constructed chain to
 876     // libpkix via cvin. Omitting for now, due to lack of coverage in upstream
 877     // NSS tests for that feature.
 878     scoped_cvout.Clear();
 879     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 880     status = PKIXVerifyCert(cert_handle,
 881                             true,
 882                             true,
 883                             cert_io_enabled,
 884                             NULL,
 885                             0,
 886                             trust_anchors.get(),
 887                             chain_verify_callback,
 888                             cvout);
 889   }
 890
 891   if (status == SECSuccess) {
 892     AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
 893                           cvout[cvout_trust_anchor_index].value.pointer.cert,
 894                           &verify_result->public_key_hashes);
 895
 896     verify_result->is_issued_by_known_root =
 897         IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
 898     verify_result->is_issued_by_additional_trust_anchor =
 899         IsAdditionalTrustAnchor(
 900             trust_anchors.get(),
 901             cvout[cvout_trust_anchor_index].value.pointer.cert);
 902
 903     GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
 904                      cvout[cvout_trust_anchor_index].value.pointer.cert,
 905                      verify_result);
 906   }
 907
 908   CRLSetResult crl_set_result = kCRLSetUnknown;
 909   if (crl_set) {
 910     crl_set_result = CheckRevocationWithCRLSet(
 911         cvout[cvout_cert_list_index].value.pointer.chain,
 912         cvout[cvout_trust_anchor_index].value.pointer.cert,
 913         crl_set);
 914     if (crl_set_result == kCRLSetRevoked) {
 915       PORT_SetError(SEC_ERROR_REVOKED_CERTIFICATE);
 916       status = SECFailure;
 917     }
 918   }
 919
 920   if (status != SECSuccess) {
 921     int err = PORT_GetError();
 922     LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
 923                << " failed err=" << err;
 924     // CERT_PKIXVerifyCert rerports the wrong error code for
 925     // expired certificates (NSS bug 491174)
 926     if (err == SEC_ERROR_CERT_NOT_VALID &&
 927         (verify_result->cert_status & CERT_STATUS_DATE_INVALID))
 928       err = SEC_ERROR_EXPIRED_CERTIFICATE;
 929     CertStatus cert_status = MapCertErrorToCertStatus(err);
 930     if (cert_status) {
 931       verify_result->cert_status |= cert_status;
 932       return MapCertStatusToNetError(verify_result->cert_status);
 933     }
 934     // |err| is not a certificate error.
 935     return MapSecurityError(err);
 936   }
 937
 938   if (IsCertStatusError(verify_result->cert_status))
 939     return MapCertStatusToNetError(verify_result->cert_status);
 940
 941   if ((flags & CertVerifier::VERIFY_EV_CERT) && is_ev_candidate) {
 942     check_revocation |=
 943         crl_set_result != kCRLSetOk &&
 944         cert_io_enabled &&
 945         (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY);
 946     if (check_revocation)
 947       verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 948
 949     if (VerifyEV(cert_handle,
 950                  flags,
 951                  crl_set,
 952                  check_revocation,
 953                  metadata,
 954                  ev_policy_oid,
 955                  trust_anchors.get(),
 956                  chain_verify_callback)) {
 957       verify_result->cert_status |= CERT_STATUS_IS_EV;
 958     }
 959   }
 960
 961   return OK;
 962 }
 963
 964 int CertVerifyProcNSS::VerifyInternal(
 965     X509Certificate* cert,
 966     const std::string& hostname,
 967     const std::string& ocsp_response,
 968     int flags,
 969     CRLSet* crl_set,
 970     const CertificateList& additional_trust_anchors,
 971     CertVerifyResult* verify_result) {
 972   return VerifyInternalImpl(cert, hostname, ocsp_response, flags, crl_set,
 973                             additional_trust_anchors,
 974                             NULL,  // chain_verify_callback
 975                             verify_result);
 976 }
 977
 978 }  // namespace net