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