net/cert/cert_verify_proc_win.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_win.h"
   6
   7 #include <string>
   8 #include <vector>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/sha1.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/strings/utf_string_conversions.h"
  14 #include "crypto/capi_util.h"
  15 #include "crypto/scoped_capi_types.h"
  16 #include "crypto/sha2.h"
  17 #include "net/base/net_errors.h"
  18 #include "net/cert/asn1_util.h"
  19 #include "net/cert/cert_status_flags.h"
  20 #include "net/cert/cert_verifier.h"
  21 #include "net/cert/cert_verify_result.h"
  22 #include "net/cert/crl_set.h"
  23 #include "net/cert/ev_root_ca_metadata.h"
  24 #include "net/cert/test_root_certs.h"
  25 #include "net/cert/x509_certificate.h"
  26 #include "net/cert/x509_certificate_known_roots_win.h"
  27
  28 #pragma comment(lib, "crypt32.lib")
  29
  30 #if !defined(CERT_TRUST_HAS_WEAK_SIGNATURE)
  31 // This was introduced in Windows 8 / Windows Server 2012, but retroactively
  32 // ported as far back as Windows XP via system update.
  33 #define CERT_TRUST_HAS_WEAK_SIGNATURE 0x00100000
  34 #endif
  35
  36 namespace net {
  37
  38 namespace {
  39
  40 struct FreeChainEngineFunctor {
  41   void operator()(HCERTCHAINENGINE engine) const {
  42     if (engine)
  43       CertFreeCertificateChainEngine(engine);
  44   }
  45 };
  46
  47 struct FreeCertChainContextFunctor {
  48   void operator()(PCCERT_CHAIN_CONTEXT chain_context) const {
  49     if (chain_context)
  50       CertFreeCertificateChain(chain_context);
  51   }
  52 };
  53
  54 struct FreeCertContextFunctor {
  55   void operator()(PCCERT_CONTEXT context) const {
  56     if (context)
  57       CertFreeCertificateContext(context);
  58   }
  59 };
  60
  61 typedef crypto::ScopedCAPIHandle<HCERTCHAINENGINE, FreeChainEngineFunctor>
  62     ScopedHCERTCHAINENGINE;
  63
  64 typedef scoped_ptr<const CERT_CHAIN_CONTEXT, FreeCertChainContextFunctor>
  65     ScopedPCCERT_CHAIN_CONTEXT;
  66
  67 typedef scoped_ptr<const CERT_CONTEXT, FreeCertContextFunctor>
  68     ScopedPCCERT_CONTEXT;
  69
  70 //-----------------------------------------------------------------------------
  71
  72 int MapSecurityError(SECURITY_STATUS err) {
  73   // There are numerous security error codes, but these are the ones we thus
  74   // far find interesting.
  75   switch (err) {
  76     case SEC_E_WRONG_PRINCIPAL:  // Schannel
  77     case CERT_E_CN_NO_MATCH:  // CryptoAPI
  78       return ERR_CERT_COMMON_NAME_INVALID;
  79     case SEC_E_UNTRUSTED_ROOT:  // Schannel
  80     case CERT_E_UNTRUSTEDROOT:  // CryptoAPI
  81       return ERR_CERT_AUTHORITY_INVALID;
  82     case SEC_E_CERT_EXPIRED:  // Schannel
  83     case CERT_E_EXPIRED:  // CryptoAPI
  84       return ERR_CERT_DATE_INVALID;
  85     case CRYPT_E_NO_REVOCATION_CHECK:
  86       return ERR_CERT_NO_REVOCATION_MECHANISM;
  87     case CRYPT_E_REVOCATION_OFFLINE:
  88       return ERR_CERT_UNABLE_TO_CHECK_REVOCATION;
  89     case CRYPT_E_REVOKED:  // Schannel and CryptoAPI
  90       return ERR_CERT_REVOKED;
  91     case SEC_E_CERT_UNKNOWN:
  92     case CERT_E_ROLE:
  93       return ERR_CERT_INVALID;
  94     case CERT_E_WRONG_USAGE:
  95       // TODO(wtc): Should we add ERR_CERT_WRONG_USAGE?
  96       return ERR_CERT_INVALID;
  97     // We received an unexpected_message or illegal_parameter alert message
  98     // from the server.
  99     case SEC_E_ILLEGAL_MESSAGE:
 100       return ERR_SSL_PROTOCOL_ERROR;
 101     case SEC_E_ALGORITHM_MISMATCH:
 102       return ERR_SSL_VERSION_OR_CIPHER_MISMATCH;
 103     case SEC_E_INVALID_HANDLE:
 104       return ERR_UNEXPECTED;
 105     case SEC_E_OK:
 106       return OK;
 107     default:
 108       LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
 109       return ERR_FAILED;
 110   }
 111 }
 112
 113 // Map the errors in the chain_context->TrustStatus.dwErrorStatus returned by
 114 // CertGetCertificateChain to our certificate status flags.
 115 int MapCertChainErrorStatusToCertStatus(DWORD error_status) {
 116   CertStatus cert_status = 0;
 117
 118   // We don't include CERT_TRUST_IS_NOT_TIME_NESTED because it's obsolete and
 119   // we wouldn't consider it an error anyway
 120   const DWORD kDateInvalidErrors = CERT_TRUST_IS_NOT_TIME_VALID |
 121                                    CERT_TRUST_CTL_IS_NOT_TIME_VALID;
 122   if (error_status & kDateInvalidErrors)
 123     cert_status |= CERT_STATUS_DATE_INVALID;
 124
 125   const DWORD kAuthorityInvalidErrors = CERT_TRUST_IS_UNTRUSTED_ROOT |
 126                                         CERT_TRUST_IS_EXPLICIT_DISTRUST |
 127                                         CERT_TRUST_IS_PARTIAL_CHAIN;
 128   if (error_status & kAuthorityInvalidErrors)
 129     cert_status |= CERT_STATUS_AUTHORITY_INVALID;
 130
 131   if ((error_status & CERT_TRUST_REVOCATION_STATUS_UNKNOWN) &&
 132       !(error_status & CERT_TRUST_IS_OFFLINE_REVOCATION))
 133     cert_status |= CERT_STATUS_NO_REVOCATION_MECHANISM;
 134
 135   if (error_status & CERT_TRUST_IS_OFFLINE_REVOCATION)
 136     cert_status |= CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
 137
 138   if (error_status & CERT_TRUST_IS_REVOKED)
 139     cert_status |= CERT_STATUS_REVOKED;
 140
 141   const DWORD kWrongUsageErrors = CERT_TRUST_IS_NOT_VALID_FOR_USAGE |
 142                                   CERT_TRUST_CTL_IS_NOT_VALID_FOR_USAGE;
 143   if (error_status & kWrongUsageErrors) {
 144     // TODO(wtc): Should we add CERT_STATUS_WRONG_USAGE?
 145     cert_status |= CERT_STATUS_INVALID;
 146   }
 147
 148   if (error_status & CERT_TRUST_IS_NOT_SIGNATURE_VALID) {
 149     // Check for a signature that does not meet the OS criteria for strong
 150     // signatures.
 151     // Note: These checks may be more restrictive than the current weak key
 152     // criteria implemented within CertVerifier, such as excluding SHA-1 or
 153     // excluding RSA keys < 2048 bits. However, if the user has configured
 154     // these more stringent checks, respect that configuration and err on the
 155     // more restrictive criteria.
 156     if (error_status & CERT_TRUST_HAS_WEAK_SIGNATURE) {
 157       cert_status |= CERT_STATUS_WEAK_KEY;
 158     } else {
 159       cert_status |= CERT_STATUS_INVALID;
 160     }
 161   }
 162
 163   // The rest of the errors.
 164   const DWORD kCertInvalidErrors =
 165       CERT_TRUST_IS_CYCLIC |
 166       CERT_TRUST_INVALID_EXTENSION |
 167       CERT_TRUST_INVALID_POLICY_CONSTRAINTS |
 168       CERT_TRUST_INVALID_BASIC_CONSTRAINTS |
 169       CERT_TRUST_INVALID_NAME_CONSTRAINTS |
 170       CERT_TRUST_CTL_IS_NOT_SIGNATURE_VALID |
 171       CERT_TRUST_HAS_NOT_SUPPORTED_NAME_CONSTRAINT |
 172       CERT_TRUST_HAS_NOT_DEFINED_NAME_CONSTRAINT |
 173       CERT_TRUST_HAS_NOT_PERMITTED_NAME_CONSTRAINT |
 174       CERT_TRUST_HAS_EXCLUDED_NAME_CONSTRAINT |
 175       CERT_TRUST_NO_ISSUANCE_CHAIN_POLICY |
 176       CERT_TRUST_HAS_NOT_SUPPORTED_CRITICAL_EXT;
 177   if (error_status & kCertInvalidErrors)
 178     cert_status |= CERT_STATUS_INVALID;
 179
 180   return cert_status;
 181 }
 182
 183 // Returns true if any common name in the certificate's Subject field contains
 184 // a NULL character.
 185 bool CertSubjectCommonNameHasNull(PCCERT_CONTEXT cert) {
 186   CRYPT_DECODE_PARA decode_para;
 187   decode_para.cbSize = sizeof(decode_para);
 188   decode_para.pfnAlloc = crypto::CryptAlloc;
 189   decode_para.pfnFree = crypto::CryptFree;
 190   CERT_NAME_INFO* name_info = NULL;
 191   DWORD name_info_size = 0;
 192   BOOL rv;
 193   rv = CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
 194                            WINCRYPT_X509_NAME,
 195                            cert->pCertInfo->Subject.pbData,
 196                            cert->pCertInfo->Subject.cbData,
 197                            CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG,
 198                            &decode_para,
 199                            &name_info,
 200                            &name_info_size);
 201   if (rv) {
 202     scoped_ptr<CERT_NAME_INFO, base::FreeDeleter> scoped_name_info(name_info);
 203
 204     // The Subject field may have multiple common names.  According to the
 205     // "PKI Layer Cake" paper, CryptoAPI uses every common name in the
 206     // Subject field, so we inspect every common name.
 207     //
 208     // From RFC 5280:
 209     // X520CommonName ::= CHOICE {
 210     //       teletexString     TeletexString   (SIZE (1..ub-common-name)),
 211     //       printableString   PrintableString (SIZE (1..ub-common-name)),
 212     //       universalString   UniversalString (SIZE (1..ub-common-name)),
 213     //       utf8String        UTF8String      (SIZE (1..ub-common-name)),
 214     //       bmpString         BMPString       (SIZE (1..ub-common-name)) }
 215     //
 216     // We also check IA5String and VisibleString.
 217     for (DWORD i = 0; i < name_info->cRDN; ++i) {
 218       PCERT_RDN rdn = &name_info->rgRDN[i];
 219       for (DWORD j = 0; j < rdn->cRDNAttr; ++j) {
 220         PCERT_RDN_ATTR rdn_attr = &rdn->rgRDNAttr[j];
 221         if (strcmp(rdn_attr->pszObjId, szOID_COMMON_NAME) == 0) {
 222           switch (rdn_attr->dwValueType) {
 223             // After the CryptoAPI ASN.1 security vulnerabilities described in
 224             // http://www.microsoft.com/technet/security/Bulletin/MS09-056.mspx
 225             // were patched, we get CERT_RDN_ENCODED_BLOB for a common name
 226             // that contains a NULL character.
 227             case CERT_RDN_ENCODED_BLOB:
 228               break;
 229             // Array of 8-bit characters.
 230             case CERT_RDN_PRINTABLE_STRING:
 231             case CERT_RDN_TELETEX_STRING:
 232             case CERT_RDN_IA5_STRING:
 233             case CERT_RDN_VISIBLE_STRING:
 234               for (DWORD k = 0; k < rdn_attr->Value.cbData; ++k) {
 235                 if (rdn_attr->Value.pbData[k] == '\0')
 236                   return true;
 237               }
 238               break;
 239             // Array of 16-bit characters.
 240             case CERT_RDN_BMP_STRING:
 241             case CERT_RDN_UTF8_STRING: {
 242               DWORD num_wchars = rdn_attr->Value.cbData / 2;
 243               wchar_t* common_name =
 244                   reinterpret_cast<wchar_t*>(rdn_attr->Value.pbData);
 245               for (DWORD k = 0; k < num_wchars; ++k) {
 246                 if (common_name[k] == L'\0')
 247                   return true;
 248               }
 249               break;
 250             }
 251             // Array of ints (32-bit).
 252             case CERT_RDN_UNIVERSAL_STRING: {
 253               DWORD num_ints = rdn_attr->Value.cbData / 4;
 254               int* common_name =
 255                   reinterpret_cast<int*>(rdn_attr->Value.pbData);
 256               for (DWORD k = 0; k < num_ints; ++k) {
 257                 if (common_name[k] == 0)
 258                   return true;
 259               }
 260               break;
 261             }
 262             default:
 263               NOTREACHED();
 264               break;
 265           }
 266         }
 267       }
 268     }
 269   }
 270   return false;
 271 }
 272
 273 // IsIssuedByKnownRoot returns true if the given chain is rooted at a root CA
 274 // which we recognise as a standard root.
 275 // static
 276 bool IsIssuedByKnownRoot(PCCERT_CHAIN_CONTEXT chain_context) {
 277   PCERT_SIMPLE_CHAIN first_chain = chain_context->rgpChain[0];
 278   int num_elements = first_chain->cElement;
 279   if (num_elements < 1)
 280     return false;
 281   PCERT_CHAIN_ELEMENT* element = first_chain->rgpElement;
 282   PCCERT_CONTEXT cert = element[num_elements - 1]->pCertContext;
 283
 284   SHA1HashValue hash = X509Certificate::CalculateFingerprint(cert);
 285   return IsSHA1HashInSortedArray(
 286       hash, &kKnownRootCertSHA1Hashes[0][0], sizeof(kKnownRootCertSHA1Hashes));
 287 }
 288
 289 // Saves some information about the certificate chain |chain_context| in
 290 // |*verify_result|. The caller MUST initialize |*verify_result| before
 291 // calling this function.
 292 void GetCertChainInfo(PCCERT_CHAIN_CONTEXT chain_context,
 293                       CertVerifyResult* verify_result) {
 294   if (chain_context->cChain == 0)
 295     return;
 296
 297   PCERT_SIMPLE_CHAIN first_chain = chain_context->rgpChain[0];
 298   int num_elements = first_chain->cElement;
 299   PCERT_CHAIN_ELEMENT* element = first_chain->rgpElement;
 300
 301   PCCERT_CONTEXT verified_cert = NULL;
 302   std::vector<PCCERT_CONTEXT> verified_chain;
 303
 304   bool has_root_ca = num_elements > 1 &&
 305       !(chain_context->TrustStatus.dwErrorStatus &
 306           CERT_TRUST_IS_PARTIAL_CHAIN);
 307
 308   // Each chain starts with the end entity certificate (i = 0) and ends with
 309   // either the root CA certificate or the last available intermediate. If a
 310   // root CA certificate is present, do not inspect the signature algorithm of
 311   // the root CA certificate because the signature on the trust anchor is not
 312   // important.
 313   if (has_root_ca) {
 314     // If a full chain was constructed, regardless of whether it was trusted,
 315     // don't inspect the root's signature algorithm.
 316     num_elements -= 1;
 317   }
 318
 319   for (int i = 0; i < num_elements; ++i) {
 320     PCCERT_CONTEXT cert = element[i]->pCertContext;
 321     if (i == 0) {
 322       verified_cert = cert;
 323     } else {
 324       verified_chain.push_back(cert);
 325     }
 326
 327     const char* algorithm = cert->pCertInfo->SignatureAlgorithm.pszObjId;
 328     if (strcmp(algorithm, szOID_RSA_MD5RSA) == 0) {
 329       // md5WithRSAEncryption: 1.2.840.113549.1.1.4
 330       verify_result->has_md5 = true;
 331     } else if (strcmp(algorithm, szOID_RSA_MD2RSA) == 0) {
 332       // md2WithRSAEncryption: 1.2.840.113549.1.1.2
 333       verify_result->has_md2 = true;
 334     } else if (strcmp(algorithm, szOID_RSA_MD4RSA) == 0) {
 335       // md4WithRSAEncryption: 1.2.840.113549.1.1.3
 336       verify_result->has_md4 = true;
 337     } else if (strcmp(algorithm, szOID_RSA_SHA1RSA) == 0 ||
 338                strcmp(algorithm, szOID_X957_SHA1DSA) == 0 ||
 339                strcmp(algorithm, szOID_ECDSA_SHA1) == 0) {
 340       // sha1WithRSAEncryption: 1.2.840.113549.1.1.5
 341       // id-dsa-with-sha1: 1.2.840.10040.4.3
 342       // ecdsa-with-SHA1: 1.2.840.10045.4.1
 343       verify_result->has_sha1 = true;
 344     }
 345   }
 346
 347   if (verified_cert) {
 348     // Add the root certificate, if present, as it was not added above.
 349     if (has_root_ca)
 350       verified_chain.push_back(element[num_elements]->pCertContext);
 351     verify_result->verified_cert =
 352           X509Certificate::CreateFromHandle(verified_cert, verified_chain);
 353   }
 354 }
 355
 356 // Decodes the cert's certificatePolicies extension into a CERT_POLICIES_INFO
 357 // structure and stores it in *output.
 358 void GetCertPoliciesInfo(
 359     PCCERT_CONTEXT cert,
 360     scoped_ptr<CERT_POLICIES_INFO, base::FreeDeleter>* output) {
 361   PCERT_EXTENSION extension = CertFindExtension(szOID_CERT_POLICIES,
 362                                                 cert->pCertInfo->cExtension,
 363                                                 cert->pCertInfo->rgExtension);
 364   if (!extension)
 365     return;
 366
 367   CRYPT_DECODE_PARA decode_para;
 368   decode_para.cbSize = sizeof(decode_para);
 369   decode_para.pfnAlloc = crypto::CryptAlloc;
 370   decode_para.pfnFree = crypto::CryptFree;
 371   CERT_POLICIES_INFO* policies_info = NULL;
 372   DWORD policies_info_size = 0;
 373   BOOL rv;
 374   rv = CryptDecodeObjectEx(X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
 375                            szOID_CERT_POLICIES,
 376                            extension->Value.pbData,
 377                            extension->Value.cbData,
 378                            CRYPT_DECODE_ALLOC_FLAG | CRYPT_DECODE_NOCOPY_FLAG,
 379                            &decode_para,
 380                            &policies_info,
 381                            &policies_info_size);
 382   if (rv)
 383     output->reset(policies_info);
 384 }
 385
 386 enum CRLSetResult {
 387   kCRLSetOk,
 388   kCRLSetUnknown,
 389   kCRLSetRevoked,
 390 };
 391
 392 // CheckRevocationWithCRLSet attempts to check each element of |chain|
 393 // against |crl_set|. It returns:
 394 //   kCRLSetRevoked: if any element of the chain is known to have been revoked.
 395 //   kCRLSetUnknown: if there is no fresh information about the leaf
 396 //       certificate in the chain or if the CRLSet has expired.
 397 //
 398 //       Only the leaf certificate is considered for coverage because some
 399 //       intermediates have CRLs with no revocations (after filtering) and
 400 //       those CRLs are pruned from the CRLSet at generation time. This means
 401 //       that some EV sites would otherwise take the hit of an OCSP lookup for
 402 //       no reason.
 403 //   kCRLSetOk: otherwise.
 404 CRLSetResult CheckRevocationWithCRLSet(PCCERT_CHAIN_CONTEXT chain,
 405                                        CRLSet* crl_set) {
 406   if (chain->cChain == 0)
 407     return kCRLSetOk;
 408
 409   const PCERT_SIMPLE_CHAIN first_chain = chain->rgpChain[0];
 410   const PCERT_CHAIN_ELEMENT* element = first_chain->rgpElement;
 411
 412   const int num_elements = first_chain->cElement;
 413   if (num_elements == 0)
 414     return kCRLSetOk;
 415
 416   // error is set to true if any errors are found. It causes such chains to be
 417   // considered as not covered.
 418   bool error = false;
 419   // last_covered is set to the coverage state of the previous certificate. The
 420   // certificates are iterated over backwards thus, after the iteration,
 421   // |last_covered| contains the coverage state of the leaf certificate.
 422   bool last_covered = false;
 423
 424   // We iterate from the root certificate down to the leaf, keeping track of
 425   // the issuer's SPKI at each step.
 426   std::string issuer_spki_hash;
 427   for (int i = num_elements - 1; i >= 0; i--) {
 428     PCCERT_CONTEXT cert = element[i]->pCertContext;
 429
 430     base::StringPiece der_bytes(
 431         reinterpret_cast<const char*>(cert->pbCertEncoded),
 432         cert->cbCertEncoded);
 433
 434     base::StringPiece spki;
 435     if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki)) {
 436       NOTREACHED();
 437       error = true;
 438       continue;
 439     }
 440
 441     const std::string spki_hash = crypto::SHA256HashString(spki);
 442
 443     const CRYPT_INTEGER_BLOB* serial_blob = &cert->pCertInfo->SerialNumber;
 444     scoped_ptr<uint8_t[]> serial_bytes(new uint8_t[serial_blob->cbData]);
 445     // The bytes of the serial number are stored little-endian.
 446     for (unsigned j = 0; j < serial_blob->cbData; j++)
 447       serial_bytes[j] = serial_blob->pbData[serial_blob->cbData - j - 1];
 448     base::StringPiece serial(reinterpret_cast<const char*>(serial_bytes.get()),
 449                              serial_blob->cbData);
 450
 451     CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
 452
 453     if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
 454       result = crl_set->CheckSerial(serial, issuer_spki_hash);
 455
 456     issuer_spki_hash = spki_hash;
 457
 458     switch (result) {
 459       case CRLSet::REVOKED:
 460         return kCRLSetRevoked;
 461       case CRLSet::UNKNOWN:
 462         last_covered = false;
 463         continue;
 464       case CRLSet::GOOD:
 465         last_covered = true;
 466         continue;
 467       default:
 468         NOTREACHED();
 469         error = true;
 470         continue;
 471     }
 472   }
 473
 474   if (error || !last_covered || crl_set->IsExpired())
 475     return kCRLSetUnknown;
 476   return kCRLSetOk;
 477 }
 478
 479 void AppendPublicKeyHashes(PCCERT_CHAIN_CONTEXT chain,
 480                            HashValueVector* hashes) {
 481   if (chain->cChain == 0)
 482     return;
 483
 484   PCERT_SIMPLE_CHAIN first_chain = chain->rgpChain[0];
 485   PCERT_CHAIN_ELEMENT* const element = first_chain->rgpElement;
 486
 487   const DWORD num_elements = first_chain->cElement;
 488   for (DWORD i = 0; i < num_elements; i++) {
 489     PCCERT_CONTEXT cert = element[i]->pCertContext;
 490
 491     base::StringPiece der_bytes(
 492         reinterpret_cast<const char*>(cert->pbCertEncoded),
 493         cert->cbCertEncoded);
 494     base::StringPiece spki_bytes;
 495     if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki_bytes))
 496       continue;
 497
 498     HashValue sha1(HASH_VALUE_SHA1);
 499     base::SHA1HashBytes(reinterpret_cast<const uint8_t*>(spki_bytes.data()),
 500                         spki_bytes.size(), sha1.data());
 501     hashes->push_back(sha1);
 502
 503     HashValue sha256(HASH_VALUE_SHA256);
 504     crypto::SHA256HashString(spki_bytes, sha256.data(), crypto::kSHA256Length);
 505     hashes->push_back(sha256);
 506   }
 507 }
 508
 509 // Returns true if the certificate is an extended-validation certificate.
 510 //
 511 // This function checks the certificatePolicies extensions of the
 512 // certificates in the certificate chain according to Section 7 (pp. 11-12)
 513 // of the EV Certificate Guidelines Version 1.0 at
 514 // http://cabforum.org/EV_Certificate_Guidelines.pdf.
 515 bool CheckEV(PCCERT_CHAIN_CONTEXT chain_context,
 516              bool rev_checking_enabled,
 517              const char* policy_oid) {
 518   DCHECK_NE(static_cast<DWORD>(0), chain_context->cChain);
 519   // If the cert doesn't match any of the policies, the
 520   // CERT_TRUST_IS_NOT_VALID_FOR_USAGE bit (0x10) in
 521   // chain_context->TrustStatus.dwErrorStatus is set.
 522   DWORD error_status = chain_context->TrustStatus.dwErrorStatus;
 523
 524   if (!rev_checking_enabled) {
 525     // If online revocation checking is disabled then we will have still
 526     // requested that the revocation cache be checked. However, that will often
 527     // cause the following two error bits to be set. These error bits mean that
 528     // the local OCSP/CRL is stale or missing entries for these certificates.
 529     // Since they are expected, we mask them away.
 530     error_status &= ~(CERT_TRUST_IS_OFFLINE_REVOCATION |
 531                       CERT_TRUST_REVOCATION_STATUS_UNKNOWN);
 532   }
 533   if (!chain_context->cChain || error_status != CERT_TRUST_NO_ERROR)
 534     return false;
 535
 536   // Check the end certificate simple chain (chain_context->rgpChain[0]).
 537   // If the end certificate's certificatePolicies extension contains the
 538   // EV policy OID of the root CA, return true.
 539   PCERT_CHAIN_ELEMENT* element = chain_context->rgpChain[0]->rgpElement;
 540   int num_elements = chain_context->rgpChain[0]->cElement;
 541   if (num_elements < 2)
 542     return false;
 543
 544   // Look up the EV policy OID of the root CA.
 545   PCCERT_CONTEXT root_cert = element[num_elements - 1]->pCertContext;
 546   SHA1HashValue fingerprint =
 547       X509Certificate::CalculateFingerprint(root_cert);
 548   EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
 549   return metadata->HasEVPolicyOID(fingerprint, policy_oid);
 550 }
 551
 552 }  // namespace
 553
 554 CertVerifyProcWin::CertVerifyProcWin() {}
 555
 556 CertVerifyProcWin::~CertVerifyProcWin() {}
 557
 558 bool CertVerifyProcWin::SupportsAdditionalTrustAnchors() const {
 559   return false;
 560 }
 561
 562 bool CertVerifyProcWin::SupportsOCSPStapling() const {
 563   // CERT_OCSP_RESPONSE_PROP_ID is only implemented on Vista+, but it can be
 564   // set on Windows XP without error. There is some overhead from the server
 565   // sending the OCSP response if it supports the extension, for the subset of
 566   // XP clients who will request it but be unable to use it, but this is an
 567   // acceptable trade-off for simplicity of implementation.
 568   return true;
 569 }
 570
 571 int CertVerifyProcWin::VerifyInternal(
 572     X509Certificate* cert,
 573     const std::string& hostname,
 574     const std::string& ocsp_response,
 575     int flags,
 576     CRLSet* crl_set,
 577     const CertificateList& additional_trust_anchors,
 578     CertVerifyResult* verify_result) {
 579   PCCERT_CONTEXT cert_handle = cert->os_cert_handle();
 580   if (!cert_handle)
 581     return ERR_UNEXPECTED;
 582
 583   // Build and validate certificate chain.
 584   CERT_CHAIN_PARA chain_para;
 585   memset(&chain_para, 0, sizeof(chain_para));
 586   chain_para.cbSize = sizeof(chain_para);
 587   // ExtendedKeyUsage.
 588   // We still need to request szOID_SERVER_GATED_CRYPTO and szOID_SGC_NETSCAPE
 589   // today because some certificate chains need them.  IE also requests these
 590   // two usages.
 591   static const LPCSTR usage[] = {
 592     szOID_PKIX_KP_SERVER_AUTH,
 593     szOID_SERVER_GATED_CRYPTO,
 594     szOID_SGC_NETSCAPE
 595   };
 596   chain_para.RequestedUsage.dwType = USAGE_MATCH_TYPE_OR;
 597   chain_para.RequestedUsage.Usage.cUsageIdentifier = arraysize(usage);
 598   chain_para.RequestedUsage.Usage.rgpszUsageIdentifier =
 599       const_cast<LPSTR*>(usage);
 600
 601   // Get the certificatePolicies extension of the certificate.
 602   scoped_ptr<CERT_POLICIES_INFO, base::FreeDeleter> policies_info;
 603   LPSTR ev_policy_oid = NULL;
 604   if (flags & CertVerifier::VERIFY_EV_CERT) {
 605     GetCertPoliciesInfo(cert_handle, &policies_info);
 606     if (policies_info.get()) {
 607       EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
 608       for (DWORD i = 0; i < policies_info->cPolicyInfo; ++i) {
 609         LPSTR policy_oid = policies_info->rgPolicyInfo[i].pszPolicyIdentifier;
 610         if (metadata->IsEVPolicyOID(policy_oid)) {
 611           ev_policy_oid = policy_oid;
 612           chain_para.RequestedIssuancePolicy.dwType = USAGE_MATCH_TYPE_AND;
 613           chain_para.RequestedIssuancePolicy.Usage.cUsageIdentifier = 1;
 614           chain_para.RequestedIssuancePolicy.Usage.rgpszUsageIdentifier =
 615               &ev_policy_oid;
 616           break;
 617         }
 618       }
 619     }
 620   }
 621
 622   // We can set CERT_CHAIN_RETURN_LOWER_QUALITY_CONTEXTS to get more chains.
 623   DWORD chain_flags = CERT_CHAIN_CACHE_END_CERT |
 624                       CERT_CHAIN_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT;
 625   bool rev_checking_enabled =
 626       (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED);
 627
 628   if (rev_checking_enabled) {
 629     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 630   } else {
 631     chain_flags |= CERT_CHAIN_REVOCATION_CHECK_CACHE_ONLY;
 632   }
 633
 634   // For non-test scenarios, use the default HCERTCHAINENGINE, NULL, which
 635   // corresponds to HCCE_CURRENT_USER and is is initialized as needed by
 636   // crypt32. However, when testing, it is necessary to create a new
 637   // HCERTCHAINENGINE and use that instead. This is because each
 638   // HCERTCHAINENGINE maintains a cache of information about certificates
 639   // encountered, and each test run may modify the trust status of a
 640   // certificate.
 641   ScopedHCERTCHAINENGINE chain_engine(NULL);
 642   if (TestRootCerts::HasInstance())
 643     chain_engine.reset(TestRootCerts::GetInstance()->GetChainEngine());
 644
 645   ScopedPCCERT_CONTEXT cert_list(cert->CreateOSCertChainForCert());
 646
 647   if (!ocsp_response.empty()) {
 648     // Attach the OCSP response to the chain.
 649     CRYPT_DATA_BLOB ocsp_response_blob;
 650     ocsp_response_blob.cbData = ocsp_response.size();
 651     ocsp_response_blob.pbData =
 652         reinterpret_cast<BYTE*>(const_cast<char*>(ocsp_response.data()));
 653     CertSetCertificateContextProperty(
 654         cert_list.get(), CERT_OCSP_RESPONSE_PROP_ID,
 655         CERT_SET_PROPERTY_IGNORE_PERSIST_ERROR_FLAG, &ocsp_response_blob);
 656   }
 657
 658   PCCERT_CHAIN_CONTEXT chain_context;
 659   // IE passes a non-NULL pTime argument that specifies the current system
 660   // time.  IE passes CERT_CHAIN_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT as the
 661   // chain_flags argument.
 662   if (!CertGetCertificateChain(
 663            chain_engine,
 664            cert_list.get(),
 665            NULL,  // current system time
 666            cert_list->hCertStore,
 667            &chain_para,
 668            chain_flags,
 669            NULL,  // reserved
 670            &chain_context)) {
 671     verify_result->cert_status |= CERT_STATUS_INVALID;
 672     return MapSecurityError(GetLastError());
 673   }
 674
 675   CRLSetResult crl_set_result = kCRLSetUnknown;
 676   if (crl_set)
 677     crl_set_result = CheckRevocationWithCRLSet(chain_context, crl_set);
 678
 679   if (crl_set_result == kCRLSetRevoked) {
 680     verify_result->cert_status |= CERT_STATUS_REVOKED;
 681   } else if (crl_set_result == kCRLSetUnknown &&
 682              (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY) &&
 683              !rev_checking_enabled &&
 684              ev_policy_oid != NULL) {
 685     // We don't have fresh information about this chain from the CRLSet and
 686     // it's probably an EV certificate. Retry with online revocation checking.
 687     rev_checking_enabled = true;
 688     chain_flags &= ~CERT_CHAIN_REVOCATION_CHECK_CACHE_ONLY;
 689     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 690
 691     CertFreeCertificateChain(chain_context);
 692     if (!CertGetCertificateChain(
 693              chain_engine,
 694              cert_list.get(),
 695              NULL,  // current system time
 696              cert_list->hCertStore,
 697              &chain_para,
 698              chain_flags,
 699              NULL,  // reserved
 700              &chain_context)) {
 701       verify_result->cert_status |= CERT_STATUS_INVALID;
 702       return MapSecurityError(GetLastError());
 703     }
 704   }
 705
 706   if (chain_context->TrustStatus.dwErrorStatus &
 707       CERT_TRUST_IS_NOT_VALID_FOR_USAGE) {
 708     ev_policy_oid = NULL;
 709     chain_para.RequestedIssuancePolicy.Usage.cUsageIdentifier = 0;
 710     chain_para.RequestedIssuancePolicy.Usage.rgpszUsageIdentifier = NULL;
 711     CertFreeCertificateChain(chain_context);
 712     if (!CertGetCertificateChain(
 713              chain_engine,
 714              cert_list.get(),
 715              NULL,  // current system time
 716              cert_list->hCertStore,
 717              &chain_para,
 718              chain_flags,
 719              NULL,  // reserved
 720              &chain_context)) {
 721       verify_result->cert_status |= CERT_STATUS_INVALID;
 722       return MapSecurityError(GetLastError());
 723     }
 724   }
 725
 726   CertVerifyResult temp_verify_result = *verify_result;
 727   GetCertChainInfo(chain_context, verify_result);
 728   if (!verify_result->is_issued_by_known_root &&
 729       (flags & CertVerifier::VERIFY_REV_CHECKING_REQUIRED_LOCAL_ANCHORS)) {
 730     *verify_result = temp_verify_result;
 731
 732     rev_checking_enabled = true;
 733     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 734     chain_flags &= ~CERT_CHAIN_REVOCATION_CHECK_CACHE_ONLY;
 735
 736     CertFreeCertificateChain(chain_context);
 737     if (!CertGetCertificateChain(
 738              chain_engine,
 739              cert_list.get(),
 740              NULL,  // current system time
 741              cert_list->hCertStore,
 742              &chain_para,
 743              chain_flags,
 744              NULL,  // reserved
 745              &chain_context)) {
 746       verify_result->cert_status |= CERT_STATUS_INVALID;
 747       return MapSecurityError(GetLastError());
 748     }
 749     GetCertChainInfo(chain_context, verify_result);
 750
 751     if (chain_context->TrustStatus.dwErrorStatus &
 752         CERT_TRUST_IS_OFFLINE_REVOCATION) {
 753       verify_result->cert_status |= CERT_STATUS_REVOKED;
 754     }
 755   }
 756
 757   ScopedPCCERT_CHAIN_CONTEXT scoped_chain_context(chain_context);
 758
 759   verify_result->cert_status |= MapCertChainErrorStatusToCertStatus(
 760       chain_context->TrustStatus.dwErrorStatus);
 761
 762   // Flag certificates that have a Subject common name with a NULL character.
 763   if (CertSubjectCommonNameHasNull(cert_handle))
 764     verify_result->cert_status |= CERT_STATUS_INVALID;
 765
 766   base::string16 hostname16 = base::ASCIIToUTF16(hostname);
 767
 768   SSL_EXTRA_CERT_CHAIN_POLICY_PARA extra_policy_para;
 769   memset(&extra_policy_para, 0, sizeof(extra_policy_para));
 770   extra_policy_para.cbSize = sizeof(extra_policy_para);
 771   extra_policy_para.dwAuthType = AUTHTYPE_SERVER;
 772   // Certificate name validation happens separately, later, using an internal
 773   // routine that has better support for RFC 6125 name matching.
 774   extra_policy_para.fdwChecks =
 775       0x00001000;  // SECURITY_FLAG_IGNORE_CERT_CN_INVALID
 776   extra_policy_para.pwszServerName =
 777       const_cast<base::char16*>(hostname16.c_str());
 778
 779   CERT_CHAIN_POLICY_PARA policy_para;
 780   memset(&policy_para, 0, sizeof(policy_para));
 781   policy_para.cbSize = sizeof(policy_para);
 782   policy_para.dwFlags = 0;
 783   policy_para.pvExtraPolicyPara = &extra_policy_para;
 784
 785   CERT_CHAIN_POLICY_STATUS policy_status;
 786   memset(&policy_status, 0, sizeof(policy_status));
 787   policy_status.cbSize = sizeof(policy_status);
 788
 789   if (!CertVerifyCertificateChainPolicy(
 790            CERT_CHAIN_POLICY_SSL,
 791            chain_context,
 792            &policy_para,
 793            &policy_status)) {
 794     return MapSecurityError(GetLastError());
 795   }
 796
 797   if (policy_status.dwError) {
 798     verify_result->cert_status |= MapNetErrorToCertStatus(
 799         MapSecurityError(policy_status.dwError));
 800   }
 801
 802   // TODO(wtc): Suppress CERT_STATUS_NO_REVOCATION_MECHANISM for now to be
 803   // compatible with WinHTTP, which doesn't report this error (bug 3004).
 804   verify_result->cert_status &= ~CERT_STATUS_NO_REVOCATION_MECHANISM;
 805
 806   // Perform hostname verification independent of
 807   // CertVerifyCertificateChainPolicy.
 808   if (!cert->VerifyNameMatch(hostname,
 809                              &verify_result->common_name_fallback_used)) {
 810     verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
 811   }
 812
 813   if (!rev_checking_enabled) {
 814     // If we didn't do online revocation checking then Windows will report
 815     // CERT_UNABLE_TO_CHECK_REVOCATION unless it had cached OCSP or CRL
 816     // information for every certificate. We only want to put up revoked
 817     // statuses from the offline checks so we squash this error.
 818     verify_result->cert_status &= ~CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
 819   }
 820
 821   AppendPublicKeyHashes(chain_context, &verify_result->public_key_hashes);
 822   verify_result->is_issued_by_known_root = IsIssuedByKnownRoot(chain_context);
 823
 824   if (IsCertStatusError(verify_result->cert_status))
 825     return MapCertStatusToNetError(verify_result->cert_status);
 826
 827   if (ev_policy_oid &&
 828       CheckEV(chain_context, rev_checking_enabled, ev_policy_oid)) {
 829     verify_result->cert_status |= CERT_STATUS_IS_EV;
 830   }
 831   return OK;
 832 }
 833
 834 }  // namespace net