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      1 // Copyright (c) 2011 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/base/x509_certificate.h"
      6 
      7 #include <cert.h>
      8 #include <cryptohi.h>
      9 #include <keyhi.h>
     10 #include <nss.h>
     11 #include <pk11pub.h>
     12 #include <prerror.h>
     13 #include <prtime.h>
     14 #include <secder.h>
     15 #include <secerr.h>
     16 #include <sechash.h>
     17 #include <sslerr.h>
     18 
     19 #include "base/logging.h"
     20 #include "base/memory/scoped_ptr.h"
     21 #include "base/pickle.h"
     22 #include "base/time.h"
     23 #include "crypto/nss_util.h"
     24 #include "crypto/rsa_private_key.h"
     25 #include "net/base/cert_status_flags.h"
     26 #include "net/base/cert_verify_result.h"
     27 #include "net/base/ev_root_ca_metadata.h"
     28 #include "net/base/net_errors.h"
     29 
     30 namespace net {
     31 
     32 namespace {
     33 
     34 class ScopedCERTCertificatePolicies {
     35  public:
     36   explicit ScopedCERTCertificatePolicies(CERTCertificatePolicies* policies)
     37       : policies_(policies) {}
     38 
     39   ~ScopedCERTCertificatePolicies() {
     40     if (policies_)
     41       CERT_DestroyCertificatePoliciesExtension(policies_);
     42   }
     43 
     44  private:
     45   CERTCertificatePolicies* policies_;
     46 
     47   DISALLOW_COPY_AND_ASSIGN(ScopedCERTCertificatePolicies);
     48 };
     49 
     50 // ScopedCERTValOutParam manages destruction of values in the CERTValOutParam
     51 // array that cvout points to.  cvout must be initialized as passed to
     52 // CERT_PKIXVerifyCert, so that the array must be terminated with
     53 // cert_po_end type.
     54 // When it goes out of scope, it destroys values of cert_po_trustAnchor
     55 // and cert_po_certList types, but doesn't release the array itself.
     56 class ScopedCERTValOutParam {
     57  public:
     58   explicit ScopedCERTValOutParam(CERTValOutParam* cvout)
     59       : cvout_(cvout) {}
     60 
     61   ~ScopedCERTValOutParam() {
     62     if (cvout_ == NULL)
     63       return;
     64     for (CERTValOutParam *p = cvout_; p->type != cert_po_end; p++) {
     65       switch (p->type) {
     66         case cert_po_trustAnchor:
     67           if (p->value.pointer.cert) {
     68             CERT_DestroyCertificate(p->value.pointer.cert);
     69             p->value.pointer.cert = NULL;
     70           }
     71           break;
     72         case cert_po_certList:
     73           if (p->value.pointer.chain) {
     74             CERT_DestroyCertList(p->value.pointer.chain);
     75             p->value.pointer.chain = NULL;
     76           }
     77           break;
     78         default:
     79           break;
     80       }
     81     }
     82   }
     83 
     84  private:
     85   CERTValOutParam* cvout_;
     86 
     87   DISALLOW_COPY_AND_ASSIGN(ScopedCERTValOutParam);
     88 };
     89 
     90 // Map PORT_GetError() return values to our network error codes.
     91 int MapSecurityError(int err) {
     92   switch (err) {
     93     case PR_DIRECTORY_LOOKUP_ERROR:  // DNS lookup error.
     94       return ERR_NAME_NOT_RESOLVED;
     95     case SEC_ERROR_INVALID_ARGS:
     96       return ERR_INVALID_ARGUMENT;
     97     case SSL_ERROR_BAD_CERT_DOMAIN:
     98       return ERR_CERT_COMMON_NAME_INVALID;
     99     case SEC_ERROR_INVALID_TIME:
    100     case SEC_ERROR_EXPIRED_CERTIFICATE:
    101     case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
    102       return ERR_CERT_DATE_INVALID;
    103     case SEC_ERROR_UNKNOWN_ISSUER:
    104     case SEC_ERROR_UNTRUSTED_ISSUER:
    105     case SEC_ERROR_CA_CERT_INVALID:
    106       return ERR_CERT_AUTHORITY_INVALID;
    107     case SEC_ERROR_REVOKED_CERTIFICATE:
    108     case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
    109       return ERR_CERT_REVOKED;
    110     case SEC_ERROR_BAD_DER:
    111     case SEC_ERROR_BAD_SIGNATURE:
    112     case SEC_ERROR_CERT_NOT_VALID:
    113     // TODO(port): add an ERR_CERT_WRONG_USAGE error code.
    114     case SEC_ERROR_CERT_USAGES_INVALID:
    115     case SEC_ERROR_INADEQUATE_KEY_USAGE:
    116     case SEC_ERROR_INADEQUATE_CERT_TYPE:
    117     case SEC_ERROR_POLICY_VALIDATION_FAILED:
    118     case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
    119     case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
    120     case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
    121     case SEC_ERROR_EXTENSION_VALUE_INVALID:
    122       return ERR_CERT_INVALID;
    123     default:
    124       LOG(WARNING) << "Unknown error " << err << " mapped to net::ERR_FAILED";
    125       return ERR_FAILED;
    126   }
    127 }
    128 
    129 // Map PORT_GetError() return values to our cert status flags.
    130 int MapCertErrorToCertStatus(int err) {
    131   switch (err) {
    132     case SSL_ERROR_BAD_CERT_DOMAIN:
    133       return CERT_STATUS_COMMON_NAME_INVALID;
    134     case SEC_ERROR_INVALID_TIME:
    135     case SEC_ERROR_EXPIRED_CERTIFICATE:
    136     case SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE:
    137       return CERT_STATUS_DATE_INVALID;
    138     case SEC_ERROR_UNKNOWN_ISSUER:
    139     case SEC_ERROR_UNTRUSTED_ISSUER:
    140     case SEC_ERROR_CA_CERT_INVALID:
    141       return CERT_STATUS_AUTHORITY_INVALID;
    142     // TODO(port): map CERT_STATUS_NO_REVOCATION_MECHANISM.
    143     case SEC_ERROR_OCSP_BAD_HTTP_RESPONSE:
    144     case SEC_ERROR_OCSP_SERVER_ERROR:
    145       return CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
    146     case SEC_ERROR_REVOKED_CERTIFICATE:
    147     case SEC_ERROR_UNTRUSTED_CERT:  // Treat as revoked.
    148       return CERT_STATUS_REVOKED;
    149     case SEC_ERROR_BAD_DER:
    150     case SEC_ERROR_BAD_SIGNATURE:
    151     case SEC_ERROR_CERT_NOT_VALID:
    152     // TODO(port): add a CERT_STATUS_WRONG_USAGE error code.
    153     case SEC_ERROR_CERT_USAGES_INVALID:
    154     case SEC_ERROR_INADEQUATE_KEY_USAGE:  // Key usage.
    155     case SEC_ERROR_INADEQUATE_CERT_TYPE:  // Extended key usage and whether
    156                                           // the certificate is a CA.
    157     case SEC_ERROR_POLICY_VALIDATION_FAILED:
    158     case SEC_ERROR_CERT_NOT_IN_NAME_SPACE:
    159     case SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID:
    160     case SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION:
    161     case SEC_ERROR_EXTENSION_VALUE_INVALID:
    162       return CERT_STATUS_INVALID;
    163     default:
    164       return 0;
    165   }
    166 }
    167 
    168 // Saves some information about the certificate chain cert_list in
    169 // *verify_result.  The caller MUST initialize *verify_result before calling
    170 // this function.
    171 // Note that cert_list[0] is the end entity certificate and cert_list doesn't
    172 // contain the root CA certificate.
    173 void GetCertChainInfo(CERTCertList* cert_list,
    174                       CertVerifyResult* verify_result) {
    175   // NOTE: Using a NSS library before 3.12.3.1 will crash below.  To see the
    176   // NSS version currently in use:
    177   // 1. use ldd on the chrome executable for NSS's location (ie. libnss3.so*)
    178   // 2. use ident libnss3.so* for the library's version
    179   DCHECK(cert_list);
    180   int i = 0;
    181   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
    182        !CERT_LIST_END(node, cert_list);
    183        node = CERT_LIST_NEXT(node), i++) {
    184     SECAlgorithmID& signature = node->cert->signature;
    185     SECOidTag oid_tag = SECOID_FindOIDTag(&signature.algorithm);
    186     switch (oid_tag) {
    187       case SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION:
    188         verify_result->has_md5 = true;
    189         if (i != 0)
    190           verify_result->has_md5_ca = true;
    191         break;
    192       case SEC_OID_PKCS1_MD2_WITH_RSA_ENCRYPTION:
    193         verify_result->has_md2 = true;
    194         if (i != 0)
    195           verify_result->has_md2_ca = true;
    196         break;
    197       case SEC_OID_PKCS1_MD4_WITH_RSA_ENCRYPTION:
    198         verify_result->has_md4 = true;
    199         break;
    200       default:
    201         break;
    202     }
    203   }
    204 }
    205 
    206 // IsKnownRoot returns true if the given certificate is one that we believe
    207 // is a standard (as opposed to user-installed) root.
    208 bool IsKnownRoot(CERTCertificate* root) {
    209   if (!root->slot)
    210     return false;
    211 
    212   // This magic name is taken from
    213   // http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/security/nss/lib/ckfw/builtins/constants.c&rev=1.13&mark=86,89#79
    214   return 0 == strcmp(PK11_GetSlotName(root->slot),
    215                      "NSS Builtin Objects");
    216 }
    217 
    218 typedef char* (*CERTGetNameFunc)(CERTName* name);
    219 
    220 void ParsePrincipal(CERTName* name,
    221                     CertPrincipal* principal) {
    222   // TODO(jcampan): add business_category and serial_number.
    223   // TODO(wtc): NSS has the CERT_GetOrgName, CERT_GetOrgUnitName, and
    224   // CERT_GetDomainComponentName functions, but they return only the most
    225   // general (the first) RDN.  NSS doesn't have a function for the street
    226   // address.
    227   static const SECOidTag kOIDs[] = {
    228       SEC_OID_AVA_STREET_ADDRESS,
    229       SEC_OID_AVA_ORGANIZATION_NAME,
    230       SEC_OID_AVA_ORGANIZATIONAL_UNIT_NAME,
    231       SEC_OID_AVA_DC };
    232 
    233   std::vector<std::string>* values[] = {
    234       &principal->street_addresses,
    235       &principal->organization_names,
    236       &principal->organization_unit_names,
    237       &principal->domain_components };
    238   DCHECK(arraysize(kOIDs) == arraysize(values));
    239 
    240   CERTRDN** rdns = name->rdns;
    241   for (size_t rdn = 0; rdns[rdn]; ++rdn) {
    242     CERTAVA** avas = rdns[rdn]->avas;
    243     for (size_t pair = 0; avas[pair] != 0; ++pair) {
    244       SECOidTag tag = CERT_GetAVATag(avas[pair]);
    245       for (size_t oid = 0; oid < arraysize(kOIDs); ++oid) {
    246         if (kOIDs[oid] == tag) {
    247           SECItem* decode_item = CERT_DecodeAVAValue(&avas[pair]->value);
    248           if (!decode_item)
    249             break;
    250           // TODO(wtc): Pass decode_item to CERT_RFC1485_EscapeAndQuote.
    251           std::string value(reinterpret_cast<char*>(decode_item->data),
    252                             decode_item->len);
    253           values[oid]->push_back(value);
    254           SECITEM_FreeItem(decode_item, PR_TRUE);
    255           break;
    256         }
    257       }
    258     }
    259   }
    260 
    261   // Get CN, L, S, and C.
    262   CERTGetNameFunc get_name_funcs[4] = {
    263       CERT_GetCommonName, CERT_GetLocalityName,
    264       CERT_GetStateName, CERT_GetCountryName };
    265   std::string* single_values[4] = {
    266       &principal->common_name, &principal->locality_name,
    267       &principal->state_or_province_name, &principal->country_name };
    268   for (size_t i = 0; i < arraysize(get_name_funcs); ++i) {
    269     char* value = get_name_funcs[i](name);
    270     if (value) {
    271       single_values[i]->assign(value);
    272       PORT_Free(value);
    273     }
    274   }
    275 }
    276 
    277 void ParseDate(SECItem* der_date, base::Time* result) {
    278   PRTime prtime;
    279   SECStatus rv = DER_DecodeTimeChoice(&prtime, der_date);
    280   DCHECK(rv == SECSuccess);
    281   *result = crypto::PRTimeToBaseTime(prtime);
    282 }
    283 
    284 void GetCertSubjectAltNamesOfType(X509Certificate::OSCertHandle cert_handle,
    285                                   CERTGeneralNameType name_type,
    286                                   std::vector<std::string>* result) {
    287   // For future extension: We only support general names of types
    288   // RFC822Name, DNSName or URI.
    289   DCHECK(name_type == certRFC822Name ||
    290          name_type == certDNSName ||
    291          name_type == certURI);
    292 
    293   SECItem alt_name;
    294   SECStatus rv = CERT_FindCertExtension(cert_handle,
    295       SEC_OID_X509_SUBJECT_ALT_NAME, &alt_name);
    296   if (rv != SECSuccess)
    297     return;
    298 
    299   PRArenaPool* arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
    300   DCHECK(arena != NULL);
    301 
    302   CERTGeneralName* alt_name_list;
    303   alt_name_list = CERT_DecodeAltNameExtension(arena, &alt_name);
    304   SECITEM_FreeItem(&alt_name, PR_FALSE);
    305 
    306   CERTGeneralName* name = alt_name_list;
    307   while (name) {
    308     // All of the general name types we support are encoded as
    309     // IA5String. In general, we should be switching off
    310     // |name->type| and doing type-appropriate conversions.
    311     if (name->type == name_type) {
    312       unsigned char* p = name->name.other.data;
    313       int len = name->name.other.len;
    314       std::string value = std::string(reinterpret_cast<char*>(p), len);
    315       result->push_back(value);
    316     }
    317     name = CERT_GetNextGeneralName(name);
    318     if (name == alt_name_list)
    319       break;
    320   }
    321   PORT_FreeArena(arena, PR_FALSE);
    322 }
    323 
    324 // Forward declarations.
    325 SECStatus RetryPKIXVerifyCertWithWorkarounds(
    326     X509Certificate::OSCertHandle cert_handle, int num_policy_oids,
    327     std::vector<CERTValInParam>* cvin, CERTValOutParam* cvout);
    328 SECOidTag GetFirstCertPolicy(X509Certificate::OSCertHandle cert_handle);
    329 
    330 // Call CERT_PKIXVerifyCert for the cert_handle.
    331 // Verification results are stored in an array of CERTValOutParam.
    332 // If policy_oids is not NULL and num_policy_oids is positive, policies
    333 // are also checked.
    334 // Caller must initialize cvout before calling this function.
    335 SECStatus PKIXVerifyCert(X509Certificate::OSCertHandle cert_handle,
    336                          bool check_revocation,
    337                          const SECOidTag* policy_oids,
    338                          int num_policy_oids,
    339                          CERTValOutParam* cvout) {
    340   bool use_crl = check_revocation;
    341   bool use_ocsp = check_revocation;
    342 
    343   // These CAs have multiple keys, which trigger two bugs in NSS's CRL code.
    344   // 1. NSS may use one key to verify a CRL signed with another key,
    345   //    incorrectly concluding that the CRL's signature is invalid.
    346   //    Hopefully this bug will be fixed in NSS 3.12.9.
    347   // 2. NSS considers all certificates issued by the CA as revoked when it
    348   //    receives a CRL with an invalid signature.  This overly strict policy
    349   //    has been relaxed in NSS 3.12.7.  See
    350   //    https://bugzilla.mozilla.org/show_bug.cgi?id=562542.
    351   // So we have to turn off CRL checking for these CAs.  See
    352   // http://crbug.com/55695.
    353   static const char* const kMultipleKeyCA[] = {
    354     "CN=Microsoft Secure Server Authority,"
    355     "DC=redmond,DC=corp,DC=microsoft,DC=com",
    356     "CN=Microsoft Secure Server Authority",
    357   };
    358 
    359   if (!NSS_VersionCheck("3.12.7")) {
    360     for (size_t i = 0; i < arraysize(kMultipleKeyCA); ++i) {
    361       if (strcmp(cert_handle->issuerName, kMultipleKeyCA[i]) == 0) {
    362         use_crl = false;
    363         break;
    364       }
    365     }
    366   }
    367 
    368   PRUint64 revocation_method_flags =
    369       CERT_REV_M_DO_NOT_TEST_USING_THIS_METHOD |
    370       CERT_REV_M_ALLOW_NETWORK_FETCHING |
    371       CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE |
    372       CERT_REV_M_IGNORE_MISSING_FRESH_INFO |
    373       CERT_REV_M_STOP_TESTING_ON_FRESH_INFO;
    374   PRUint64 revocation_method_independent_flags =
    375       CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;
    376   if (policy_oids && num_policy_oids > 0) {
    377     // EV verification requires revocation checking.  Consider the certificate
    378     // revoked if we don't have revocation info.
    379     // TODO(wtc): Add a bool parameter to expressly specify we're doing EV
    380     // verification or we want strict revocation flags.
    381     revocation_method_flags |= CERT_REV_M_REQUIRE_INFO_ON_MISSING_SOURCE;
    382     revocation_method_independent_flags |=
    383         CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE;
    384   } else {
    385     revocation_method_flags |= CERT_REV_M_SKIP_TEST_ON_MISSING_SOURCE;
    386     revocation_method_independent_flags |=
    387         CERT_REV_MI_NO_OVERALL_INFO_REQUIREMENT;
    388   }
    389   PRUint64 method_flags[2];
    390   method_flags[cert_revocation_method_crl] = revocation_method_flags;
    391   method_flags[cert_revocation_method_ocsp] = revocation_method_flags;
    392 
    393   if (use_crl) {
    394     method_flags[cert_revocation_method_crl] |=
    395         CERT_REV_M_TEST_USING_THIS_METHOD;
    396   }
    397   if (use_ocsp) {
    398     method_flags[cert_revocation_method_ocsp] |=
    399         CERT_REV_M_TEST_USING_THIS_METHOD;
    400   }
    401 
    402   CERTRevocationMethodIndex preferred_revocation_methods[1];
    403   if (use_ocsp) {
    404     preferred_revocation_methods[0] = cert_revocation_method_ocsp;
    405   } else {
    406     preferred_revocation_methods[0] = cert_revocation_method_crl;
    407   }
    408 
    409   CERTRevocationFlags revocation_flags;
    410   revocation_flags.leafTests.number_of_defined_methods =
    411       arraysize(method_flags);
    412   revocation_flags.leafTests.cert_rev_flags_per_method = method_flags;
    413   revocation_flags.leafTests.number_of_preferred_methods =
    414       arraysize(preferred_revocation_methods);
    415   revocation_flags.leafTests.preferred_methods = preferred_revocation_methods;
    416   revocation_flags.leafTests.cert_rev_method_independent_flags =
    417       revocation_method_independent_flags;
    418 
    419   revocation_flags.chainTests.number_of_defined_methods =
    420       arraysize(method_flags);
    421   revocation_flags.chainTests.cert_rev_flags_per_method = method_flags;
    422   revocation_flags.chainTests.number_of_preferred_methods =
    423       arraysize(preferred_revocation_methods);
    424   revocation_flags.chainTests.preferred_methods = preferred_revocation_methods;
    425   revocation_flags.chainTests.cert_rev_method_independent_flags =
    426       revocation_method_independent_flags;
    427 
    428   std::vector<CERTValInParam> cvin;
    429   cvin.reserve(5);
    430   CERTValInParam in_param;
    431   // No need to set cert_pi_trustAnchors here.
    432   in_param.type = cert_pi_revocationFlags;
    433   in_param.value.pointer.revocation = &revocation_flags;
    434   cvin.push_back(in_param);
    435   if (policy_oids && num_policy_oids > 0) {
    436     in_param.type = cert_pi_policyOID;
    437     in_param.value.arraySize = num_policy_oids;
    438     in_param.value.array.oids = policy_oids;
    439     cvin.push_back(in_param);
    440   }
    441   in_param.type = cert_pi_end;
    442   cvin.push_back(in_param);
    443 
    444   SECStatus rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
    445                                      &cvin[0], cvout, NULL);
    446   if (rv != SECSuccess) {
    447     rv = RetryPKIXVerifyCertWithWorkarounds(cert_handle, num_policy_oids,
    448                                             &cvin, cvout);
    449   }
    450   return rv;
    451 }
    452 
    453 // PKIXVerifyCert calls this function to work around some bugs in
    454 // CERT_PKIXVerifyCert.  All the arguments of this function are either the
    455 // arguments or local variables of PKIXVerifyCert.
    456 SECStatus RetryPKIXVerifyCertWithWorkarounds(
    457     X509Certificate::OSCertHandle cert_handle, int num_policy_oids,
    458     std::vector<CERTValInParam>* cvin, CERTValOutParam* cvout) {
    459   // We call this function when the first CERT_PKIXVerifyCert call in
    460   // PKIXVerifyCert failed,  so we initialize |rv| to SECFailure.
    461   SECStatus rv = SECFailure;
    462   int nss_error = PORT_GetError();
    463   CERTValInParam in_param;
    464 
    465   // If we get SEC_ERROR_UNKNOWN_ISSUER, we may be missing an intermediate
    466   // CA certificate, so we retry with cert_pi_useAIACertFetch.
    467   // cert_pi_useAIACertFetch has several bugs in its error handling and
    468   // error reporting (NSS bug 528743), so we don't use it by default.
    469   // Note: When building a certificate chain, CERT_PKIXVerifyCert may
    470   // incorrectly pick a CA certificate with the same subject name as the
    471   // missing intermediate CA certificate, and  fail with the
    472   // SEC_ERROR_BAD_SIGNATURE error (NSS bug 524013), so we also retry with
    473   // cert_pi_useAIACertFetch on SEC_ERROR_BAD_SIGNATURE.
    474   if (nss_error == SEC_ERROR_UNKNOWN_ISSUER ||
    475       nss_error == SEC_ERROR_BAD_SIGNATURE) {
    476     DCHECK_EQ(cvin->back().type,  cert_pi_end);
    477     cvin->pop_back();
    478     in_param.type = cert_pi_useAIACertFetch;
    479     in_param.value.scalar.b = PR_TRUE;
    480     cvin->push_back(in_param);
    481     in_param.type = cert_pi_end;
    482     cvin->push_back(in_param);
    483     rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
    484                              &(*cvin)[0], cvout, NULL);
    485     if (rv == SECSuccess)
    486       return rv;
    487     int new_nss_error = PORT_GetError();
    488     if (new_nss_error == SEC_ERROR_INVALID_ARGS ||
    489         new_nss_error == SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE ||
    490         new_nss_error == SEC_ERROR_BAD_HTTP_RESPONSE ||
    491         new_nss_error == SEC_ERROR_BAD_LDAP_RESPONSE ||
    492         !IS_SEC_ERROR(new_nss_error)) {
    493       // Use the original error code because of cert_pi_useAIACertFetch's
    494       // bad error reporting.
    495       PORT_SetError(nss_error);
    496       return rv;
    497     }
    498     nss_error = new_nss_error;
    499   }
    500 
    501   // If an intermediate CA certificate has requireExplicitPolicy in its
    502   // policyConstraints extension, CERT_PKIXVerifyCert fails with
    503   // SEC_ERROR_POLICY_VALIDATION_FAILED because we didn't specify any
    504   // certificate policy (NSS bug 552775).  So we retry with the certificate
    505   // policy found in the server certificate.
    506   if (nss_error == SEC_ERROR_POLICY_VALIDATION_FAILED &&
    507       num_policy_oids == 0) {
    508     SECOidTag policy = GetFirstCertPolicy(cert_handle);
    509     if (policy != SEC_OID_UNKNOWN) {
    510       DCHECK_EQ(cvin->back().type,  cert_pi_end);
    511       cvin->pop_back();
    512       in_param.type = cert_pi_policyOID;
    513       in_param.value.arraySize = 1;
    514       in_param.value.array.oids = &policy;
    515       cvin->push_back(in_param);
    516       in_param.type = cert_pi_end;
    517       cvin->push_back(in_param);
    518       rv = CERT_PKIXVerifyCert(cert_handle, certificateUsageSSLServer,
    519                                &(*cvin)[0], cvout, NULL);
    520       if (rv != SECSuccess) {
    521         // Use the original error code.
    522         PORT_SetError(nss_error);
    523       }
    524     }
    525   }
    526 
    527   return rv;
    528 }
    529 
    530 // Decodes the certificatePolicies extension of the certificate.  Returns
    531 // NULL if the certificate doesn't have the extension or the extension can't
    532 // be decoded.  The returned value must be freed with a
    533 // CERT_DestroyCertificatePoliciesExtension call.
    534 CERTCertificatePolicies* DecodeCertPolicies(
    535     X509Certificate::OSCertHandle cert_handle) {
    536   SECItem policy_ext;
    537   SECStatus rv = CERT_FindCertExtension(
    538       cert_handle, SEC_OID_X509_CERTIFICATE_POLICIES, &policy_ext);
    539   if (rv != SECSuccess)
    540     return NULL;
    541   CERTCertificatePolicies* policies =
    542       CERT_DecodeCertificatePoliciesExtension(&policy_ext);
    543   SECITEM_FreeItem(&policy_ext, PR_FALSE);
    544   return policies;
    545 }
    546 
    547 // Returns the OID tag for the first certificate policy in the certificate's
    548 // certificatePolicies extension.  Returns SEC_OID_UNKNOWN if the certificate
    549 // has no certificate policy.
    550 SECOidTag GetFirstCertPolicy(X509Certificate::OSCertHandle cert_handle) {
    551   CERTCertificatePolicies* policies = DecodeCertPolicies(cert_handle);
    552   if (!policies)
    553     return SEC_OID_UNKNOWN;
    554   ScopedCERTCertificatePolicies scoped_policies(policies);
    555   CERTPolicyInfo* policy_info = policies->policyInfos[0];
    556   if (!policy_info)
    557     return SEC_OID_UNKNOWN;
    558   if (policy_info->oid != SEC_OID_UNKNOWN)
    559     return policy_info->oid;
    560 
    561   // The certificate policy is unknown to NSS.  We need to create a dynamic
    562   // OID tag for the policy.
    563   SECOidData od;
    564   od.oid.len = policy_info->policyID.len;
    565   od.oid.data = policy_info->policyID.data;
    566   od.offset = SEC_OID_UNKNOWN;
    567   // NSS doesn't allow us to pass an empty description, so I use a hardcoded,
    568   // default description here.  The description doesn't need to be unique for
    569   // each OID.
    570   od.desc = "a certificate policy";
    571   od.mechanism = CKM_INVALID_MECHANISM;
    572   od.supportedExtension = INVALID_CERT_EXTENSION;
    573   return SECOID_AddEntry(&od);
    574 }
    575 
    576 bool CheckCertPolicies(X509Certificate::OSCertHandle cert_handle,
    577                        SECOidTag ev_policy_tag) {
    578   CERTCertificatePolicies* policies = DecodeCertPolicies(cert_handle);
    579   if (!policies) {
    580     LOG(ERROR) << "Cert has no policies extension or extension couldn't be "
    581                   "decoded.";
    582     return false;
    583   }
    584   ScopedCERTCertificatePolicies scoped_policies(policies);
    585   CERTPolicyInfo** policy_infos = policies->policyInfos;
    586   while (*policy_infos != NULL) {
    587     CERTPolicyInfo* policy_info = *policy_infos++;
    588     SECOidTag oid_tag = policy_info->oid;
    589     if (oid_tag == SEC_OID_UNKNOWN)
    590       continue;
    591     if (oid_tag == ev_policy_tag)
    592       return true;
    593   }
    594   LOG(ERROR) << "No EV Policy Tag";
    595   return false;
    596 }
    597 
    598 SECStatus PR_CALLBACK
    599 CollectCertsCallback(void* arg, SECItem** certs, int num_certs) {
    600   X509Certificate::OSCertHandles* results =
    601       reinterpret_cast<X509Certificate::OSCertHandles*>(arg);
    602 
    603   for (int i = 0; i < num_certs; ++i) {
    604     X509Certificate::OSCertHandle handle =
    605         X509Certificate::CreateOSCertHandleFromBytes(
    606             reinterpret_cast<char*>(certs[i]->data), certs[i]->len);
    607     if (handle)
    608       results->push_back(handle);
    609   }
    610 
    611   return SECSuccess;
    612 }
    613 
    614 SHA1Fingerprint CertPublicKeyHash(CERTCertificate* cert) {
    615   SHA1Fingerprint hash;
    616   SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, hash.data,
    617                               cert->derPublicKey.data, cert->derPublicKey.len);
    618   DCHECK_EQ(rv, SECSuccess);
    619   return hash;
    620 }
    621 
    622 void AppendPublicKeyHashes(CERTCertList* cert_list,
    623                            CERTCertificate* root_cert,
    624                            std::vector<SHA1Fingerprint>* hashes) {
    625   for (CERTCertListNode* node = CERT_LIST_HEAD(cert_list);
    626        !CERT_LIST_END(node, cert_list);
    627        node = CERT_LIST_NEXT(node)) {
    628     hashes->push_back(CertPublicKeyHash(node->cert));
    629   }
    630   hashes->push_back(CertPublicKeyHash(root_cert));
    631 }
    632 
    633 }  // namespace
    634 
    635 void X509Certificate::Initialize() {
    636   ParsePrincipal(&cert_handle_->subject, &subject_);
    637   ParsePrincipal(&cert_handle_->issuer, &issuer_);
    638 
    639   ParseDate(&cert_handle_->validity.notBefore, &valid_start_);
    640   ParseDate(&cert_handle_->validity.notAfter, &valid_expiry_);
    641 
    642   fingerprint_ = CalculateFingerprint(cert_handle_);
    643 
    644   serial_number_ = std::string(
    645       reinterpret_cast<char*>(cert_handle_->serialNumber.data),
    646       cert_handle_->serialNumber.len);
    647   // Remove leading zeros.
    648   while (serial_number_.size() > 1 && serial_number_[0] == 0)
    649     serial_number_ = serial_number_.substr(1, serial_number_.size() - 1);
    650 }
    651 
    652 // static
    653 X509Certificate* X509Certificate::CreateSelfSigned(
    654     crypto::RSAPrivateKey* key,
    655     const std::string& subject,
    656     uint32 serial_number,
    657     base::TimeDelta valid_duration) {
    658   DCHECK(key);
    659 
    660   // Create info about public key.
    661   CERTSubjectPublicKeyInfo* spki =
    662       SECKEY_CreateSubjectPublicKeyInfo(key->public_key());
    663   if (!spki)
    664     return NULL;
    665 
    666   // Create the certificate request.
    667   CERTName* subject_name =
    668       CERT_AsciiToName(const_cast<char*>(subject.c_str()));
    669   CERTCertificateRequest* cert_request =
    670       CERT_CreateCertificateRequest(subject_name, spki, NULL);
    671   SECKEY_DestroySubjectPublicKeyInfo(spki);
    672 
    673   if (!cert_request) {
    674     PRErrorCode prerr = PR_GetError();
    675     LOG(ERROR) << "Failed to create certificate request: " << prerr;
    676     CERT_DestroyName(subject_name);
    677     return NULL;
    678   }
    679 
    680   PRTime now = PR_Now();
    681   PRTime not_after = now + valid_duration.InMicroseconds();
    682 
    683   // Note that the time is now in micro-second unit.
    684   CERTValidity* validity = CERT_CreateValidity(now, not_after);
    685   CERTCertificate* cert = CERT_CreateCertificate(serial_number, subject_name,
    686                                                  validity, cert_request);
    687   if (!cert) {
    688     PRErrorCode prerr = PR_GetError();
    689     LOG(ERROR) << "Failed to create certificate: " << prerr;
    690   }
    691 
    692   // Cleanup for resources used to generate the cert.
    693   CERT_DestroyName(subject_name);
    694   CERT_DestroyValidity(validity);
    695   CERT_DestroyCertificateRequest(cert_request);
    696 
    697   // Sign the cert here. The logic of this method references SignCert() in NSS
    698   // utility certutil: http://mxr.mozilla.org/security/ident?i=SignCert.
    699 
    700   // |arena| is used to encode the cert.
    701   PRArenaPool* arena = cert->arena;
    702   SECOidTag algo_id = SEC_GetSignatureAlgorithmOidTag(key->key()->keyType,
    703                                                       SEC_OID_SHA1);
    704   if (algo_id == SEC_OID_UNKNOWN) {
    705     CERT_DestroyCertificate(cert);
    706     return NULL;
    707   }
    708 
    709   SECStatus rv = SECOID_SetAlgorithmID(arena, &cert->signature, algo_id, 0);
    710   if (rv != SECSuccess) {
    711     CERT_DestroyCertificate(cert);
    712     return NULL;
    713   }
    714 
    715   // Generate a cert of version 3.
    716   *(cert->version.data) = 2;
    717   cert->version.len = 1;
    718 
    719   SECItem der;
    720   der.len = 0;
    721   der.data = NULL;
    722 
    723   // Use ASN1 DER to encode the cert.
    724   void* encode_result = SEC_ASN1EncodeItem(
    725       arena, &der, cert, SEC_ASN1_GET(CERT_CertificateTemplate));
    726   if (!encode_result) {
    727     CERT_DestroyCertificate(cert);
    728     return NULL;
    729   }
    730 
    731   // Allocate space to contain the signed cert.
    732   SECItem* result = SECITEM_AllocItem(arena, NULL, 0);
    733   if (!result) {
    734     CERT_DestroyCertificate(cert);
    735     return NULL;
    736   }
    737 
    738   // Sign the ASN1 encoded cert and save it to |result|.
    739   rv = SEC_DerSignData(arena, result, der.data, der.len, key->key(), algo_id);
    740   if (rv != SECSuccess) {
    741     CERT_DestroyCertificate(cert);
    742     return NULL;
    743   }
    744 
    745   // Save the signed result to the cert.
    746   cert->derCert = *result;
    747 
    748   X509Certificate* x509_cert =
    749       CreateFromHandle(cert, SOURCE_LONE_CERT_IMPORT, OSCertHandles());
    750   CERT_DestroyCertificate(cert);
    751   return x509_cert;
    752 }
    753 
    754 void X509Certificate::GetDNSNames(std::vector<std::string>* dns_names) const {
    755   dns_names->clear();
    756 
    757   // Compare with CERT_VerifyCertName().
    758   GetCertSubjectAltNamesOfType(cert_handle_, certDNSName, dns_names);
    759 
    760   if (dns_names->empty())
    761     dns_names->push_back(subject_.common_name);
    762 }
    763 
    764 int X509Certificate::Verify(const std::string& hostname,
    765                             int flags,
    766                             CertVerifyResult* verify_result) const {
    767   verify_result->Reset();
    768 
    769   if (IsBlacklisted()) {
    770     verify_result->cert_status |= CERT_STATUS_REVOKED;
    771     return ERR_CERT_REVOKED;
    772   }
    773 
    774   // Make sure that the hostname matches with the common name of the cert.
    775   SECStatus status = CERT_VerifyCertName(cert_handle_, hostname.c_str());
    776   if (status != SECSuccess)
    777     verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
    778 
    779   // Make sure that the cert is valid now.
    780   SECCertTimeValidity validity = CERT_CheckCertValidTimes(
    781       cert_handle_, PR_Now(), PR_TRUE);
    782   if (validity != secCertTimeValid)
    783     verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
    784 
    785   CERTValOutParam cvout[3];
    786   int cvout_index = 0;
    787   cvout[cvout_index].type = cert_po_certList;
    788   cvout[cvout_index].value.pointer.chain = NULL;
    789   int cvout_cert_list_index = cvout_index;
    790   cvout_index++;
    791   cvout[cvout_index].type = cert_po_trustAnchor;
    792   cvout[cvout_index].value.pointer.cert = NULL;
    793   int cvout_trust_anchor_index = cvout_index;
    794   cvout_index++;
    795   cvout[cvout_index].type = cert_po_end;
    796   ScopedCERTValOutParam scoped_cvout(cvout);
    797 
    798   bool check_revocation = (flags & VERIFY_REV_CHECKING_ENABLED);
    799   if (check_revocation) {
    800     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
    801   } else {
    802     // EV requires revocation checking.
    803     flags &= ~VERIFY_EV_CERT;
    804   }
    805   status = PKIXVerifyCert(cert_handle_, check_revocation, NULL, 0, cvout);
    806   if (status != SECSuccess) {
    807     int err = PORT_GetError();
    808     LOG(ERROR) << "CERT_PKIXVerifyCert for " << hostname
    809                << " failed err=" << err;
    810     // CERT_PKIXVerifyCert rerports the wrong error code for
    811     // expired certificates (NSS bug 491174)
    812     if (err == SEC_ERROR_CERT_NOT_VALID &&
    813         (verify_result->cert_status & CERT_STATUS_DATE_INVALID) != 0)
    814       err = SEC_ERROR_EXPIRED_CERTIFICATE;
    815     int cert_status = MapCertErrorToCertStatus(err);
    816     if (cert_status) {
    817       verify_result->cert_status |= cert_status;
    818       return MapCertStatusToNetError(verify_result->cert_status);
    819     }
    820     // |err| is not a certificate error.
    821     return MapSecurityError(err);
    822   }
    823 
    824   GetCertChainInfo(cvout[cvout_cert_list_index].value.pointer.chain,
    825                    verify_result);
    826   if (IsCertStatusError(verify_result->cert_status))
    827     return MapCertStatusToNetError(verify_result->cert_status);
    828 
    829   AppendPublicKeyHashes(cvout[cvout_cert_list_index].value.pointer.chain,
    830                         cvout[cvout_trust_anchor_index].value.pointer.cert,
    831                         &verify_result->public_key_hashes);
    832 
    833   verify_result->is_issued_by_known_root =
    834       IsKnownRoot(cvout[cvout_trust_anchor_index].value.pointer.cert);
    835 
    836   if ((flags & VERIFY_EV_CERT) && VerifyEV())
    837     verify_result->cert_status |= CERT_STATUS_IS_EV;
    838 
    839   if (IsPublicKeyBlacklisted(verify_result->public_key_hashes)) {
    840     verify_result->cert_status |= CERT_STATUS_AUTHORITY_INVALID;
    841     return MapCertStatusToNetError(verify_result->cert_status);
    842   }
    843 
    844   return OK;
    845 }
    846 
    847 bool X509Certificate::VerifyNameMatch(const std::string& hostname) const {
    848   return CERT_VerifyCertName(cert_handle_, hostname.c_str()) == SECSuccess;
    849 }
    850 
    851 // Studied Mozilla's code (esp. security/manager/ssl/src/nsIdentityChecking.cpp
    852 // and nsNSSCertHelper.cpp) to learn how to verify EV certificate.
    853 // TODO(wtc): A possible optimization is that we get the trust anchor from
    854 // the first PKIXVerifyCert call.  We look up the EV policy for the trust
    855 // anchor.  If the trust anchor has no EV policy, we know the cert isn't EV.
    856 // Otherwise, we pass just that EV policy (as opposed to all the EV policies)
    857 // to the second PKIXVerifyCert call.
    858 bool X509Certificate::VerifyEV() const {
    859   EVRootCAMetadata* metadata = EVRootCAMetadata::GetInstance();
    860 
    861   CERTValOutParam cvout[3];
    862   int cvout_index = 0;
    863   cvout[cvout_index].type = cert_po_trustAnchor;
    864   cvout[cvout_index].value.pointer.cert = NULL;
    865   int cvout_trust_anchor_index = cvout_index;
    866   cvout_index++;
    867   cvout[cvout_index].type = cert_po_end;
    868   ScopedCERTValOutParam scoped_cvout(cvout);
    869 
    870   SECStatus status = PKIXVerifyCert(cert_handle_,
    871                                     true,
    872                                     metadata->GetPolicyOIDs(),
    873                                     metadata->NumPolicyOIDs(),
    874                                     cvout);
    875   if (status != SECSuccess)
    876     return false;
    877 
    878   CERTCertificate* root_ca =
    879       cvout[cvout_trust_anchor_index].value.pointer.cert;
    880   if (root_ca == NULL)
    881     return false;
    882   SHA1Fingerprint fingerprint =
    883       X509Certificate::CalculateFingerprint(root_ca);
    884   SECOidTag ev_policy_tag = SEC_OID_UNKNOWN;
    885   if (!metadata->GetPolicyOID(fingerprint, &ev_policy_tag))
    886     return false;
    887 
    888   if (!CheckCertPolicies(cert_handle_, ev_policy_tag))
    889     return false;
    890 
    891   return true;
    892 }
    893 
    894 bool X509Certificate::GetDEREncoded(std::string* encoded) {
    895   if (!cert_handle_->derCert.len)
    896     return false;
    897   encoded->clear();
    898   encoded->append(reinterpret_cast<char*>(cert_handle_->derCert.data),
    899                   cert_handle_->derCert.len);
    900   return true;
    901 }
    902 
    903 // static
    904 bool X509Certificate::IsSameOSCert(X509Certificate::OSCertHandle a,
    905                                    X509Certificate::OSCertHandle b) {
    906   DCHECK(a && b);
    907   if (a == b)
    908     return true;
    909   return a->derCert.len == b->derCert.len &&
    910       memcmp(a->derCert.data, b->derCert.data, a->derCert.len) == 0;
    911 }
    912 
    913 // static
    914 X509Certificate::OSCertHandle X509Certificate::CreateOSCertHandleFromBytes(
    915     const char* data, int length) {
    916   if (length < 0)
    917     return NULL;
    918 
    919   crypto::EnsureNSSInit();
    920 
    921   if (!NSS_IsInitialized())
    922     return NULL;
    923 
    924   SECItem der_cert;
    925   der_cert.data = reinterpret_cast<unsigned char*>(const_cast<char*>(data));
    926   der_cert.len  = length;
    927   der_cert.type = siDERCertBuffer;
    928 
    929   // Parse into a certificate structure.
    930   return CERT_NewTempCertificate(CERT_GetDefaultCertDB(), &der_cert, NULL,
    931                                  PR_FALSE, PR_TRUE);
    932 }
    933 
    934 // static
    935 X509Certificate::OSCertHandles X509Certificate::CreateOSCertHandlesFromBytes(
    936     const char* data, int length, Format format) {
    937   OSCertHandles results;
    938   if (length < 0)
    939     return results;
    940 
    941   crypto::EnsureNSSInit();
    942 
    943   if (!NSS_IsInitialized())
    944     return results;
    945 
    946   switch (format) {
    947     case FORMAT_SINGLE_CERTIFICATE: {
    948       OSCertHandle handle = CreateOSCertHandleFromBytes(data, length);
    949       if (handle)
    950         results.push_back(handle);
    951       break;
    952     }
    953     case FORMAT_PKCS7: {
    954       // Make a copy since CERT_DecodeCertPackage may modify it
    955       std::vector<char> data_copy(data, data + length);
    956 
    957       SECStatus result = CERT_DecodeCertPackage(&data_copy[0],
    958           length, CollectCertsCallback, &results);
    959       if (result != SECSuccess)
    960         results.clear();
    961       break;
    962     }
    963     default:
    964       NOTREACHED() << "Certificate format " << format << " unimplemented";
    965       break;
    966   }
    967 
    968   return results;
    969 }
    970 
    971 // static
    972 X509Certificate::OSCertHandle X509Certificate::DupOSCertHandle(
    973     OSCertHandle cert_handle) {
    974   return CERT_DupCertificate(cert_handle);
    975 }
    976 
    977 // static
    978 void X509Certificate::FreeOSCertHandle(OSCertHandle cert_handle) {
    979   CERT_DestroyCertificate(cert_handle);
    980 }
    981 
    982 // static
    983 SHA1Fingerprint X509Certificate::CalculateFingerprint(
    984     OSCertHandle cert) {
    985   SHA1Fingerprint sha1;
    986   memset(sha1.data, 0, sizeof(sha1.data));
    987 
    988   DCHECK(NULL != cert->derCert.data);
    989   DCHECK(0 != cert->derCert.len);
    990 
    991   SECStatus rv = HASH_HashBuf(HASH_AlgSHA1, sha1.data,
    992                               cert->derCert.data, cert->derCert.len);
    993   DCHECK(rv == SECSuccess);
    994 
    995   return sha1;
    996 }
    997 
    998 // static
    999 X509Certificate::OSCertHandle
   1000 X509Certificate::ReadCertHandleFromPickle(const Pickle& pickle,
   1001                                           void** pickle_iter) {
   1002   const char* data;
   1003   int length;
   1004   if (!pickle.ReadData(pickle_iter, &data, &length))
   1005     return NULL;
   1006 
   1007   return CreateOSCertHandleFromBytes(data, length);
   1008 }
   1009 
   1010 // static
   1011 bool X509Certificate::WriteCertHandleToPickle(OSCertHandle cert_handle,
   1012                                               Pickle* pickle) {
   1013   return pickle->WriteData(
   1014       reinterpret_cast<const char*>(cert_handle->derCert.data),
   1015       cert_handle->derCert.len);
   1016 }
   1017 
   1018 }  // namespace net
   1019