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