net/cert/cert_verify_proc_mac.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_mac.h"
   6
   7 #include <CommonCrypto/CommonDigest.h>
   8 #include <CoreServices/CoreServices.h>
   9 #include <Security/Security.h>
  10
  11 #include <string>
  12 #include <vector>
  13
  14 #include "base/logging.h"
  15 #include "base/mac/mac_logging.h"
  16 #include "base/mac/scoped_cftyperef.h"
  17 #include "base/sha1.h"
  18 #include "base/strings/string_piece.h"
  19 #include "base/synchronization/lock.h"
  20 #include "crypto/mac_security_services_lock.h"
  21 #include "crypto/nss_util.h"
  22 #include "crypto/sha2.h"
  23 #include "net/base/net_errors.h"
  24 #include "net/cert/asn1_util.h"
  25 #include "net/cert/cert_status_flags.h"
  26 #include "net/cert/cert_verifier.h"
  27 #include "net/cert/cert_verify_result.h"
  28 #include "net/cert/crl_set.h"
  29 #include "net/cert/test_root_certs.h"
  30 #include "net/cert/x509_certificate.h"
  31 #include "net/cert/x509_certificate_known_roots_mac.h"
  32 #include "net/cert/x509_util_mac.h"
  33
  34 // From 10.7.2 libsecurity_keychain-55035/lib/SecTrustPriv.h, for use with
  35 // SecTrustCopyExtendedResult.
  36 #ifndef kSecEVOrganizationName
  37 #define kSecEVOrganizationName CFSTR("Organization")
  38 #endif
  39
  40 using base::ScopedCFTypeRef;
  41
  42 namespace net {
  43
  44 namespace {
  45
  46 typedef OSStatus (*SecTrustCopyExtendedResultFuncPtr)(SecTrustRef,
  47                                                       CFDictionaryRef*);
  48
  49 int NetErrorFromOSStatus(OSStatus status) {
  50   switch (status) {
  51     case noErr:
  52       return OK;
  53     case errSecNotAvailable:
  54     case errSecNoCertificateModule:
  55     case errSecNoPolicyModule:
  56       return ERR_NOT_IMPLEMENTED;
  57     case errSecAuthFailed:
  58       return ERR_ACCESS_DENIED;
  59     default: {
  60       OSSTATUS_LOG(ERROR, status) << "Unknown error mapped to ERR_FAILED";
  61       return ERR_FAILED;
  62     }
  63   }
  64 }
  65
  66 CertStatus CertStatusFromOSStatus(OSStatus status) {
  67   switch (status) {
  68     case noErr:
  69       return 0;
  70
  71     case CSSMERR_TP_INVALID_ANCHOR_CERT:
  72     case CSSMERR_TP_NOT_TRUSTED:
  73     case CSSMERR_TP_INVALID_CERT_AUTHORITY:
  74       return CERT_STATUS_AUTHORITY_INVALID;
  75
  76     case CSSMERR_TP_CERT_EXPIRED:
  77     case CSSMERR_TP_CERT_NOT_VALID_YET:
  78       // "Expired" and "not yet valid" collapse into a single status.
  79       return CERT_STATUS_DATE_INVALID;
  80
  81     case CSSMERR_TP_CERT_REVOKED:
  82     case CSSMERR_TP_CERT_SUSPENDED:
  83       return CERT_STATUS_REVOKED;
  84
  85     case CSSMERR_APPLETP_HOSTNAME_MISMATCH:
  86       return CERT_STATUS_COMMON_NAME_INVALID;
  87
  88     case CSSMERR_APPLETP_CRL_NOT_FOUND:
  89     case CSSMERR_APPLETP_OCSP_UNAVAILABLE:
  90     case CSSMERR_APPLETP_INCOMPLETE_REVOCATION_CHECK:
  91       return CERT_STATUS_NO_REVOCATION_MECHANISM;
  92
  93     case CSSMERR_APPLETP_CRL_EXPIRED:
  94     case CSSMERR_APPLETP_CRL_NOT_VALID_YET:
  95     case CSSMERR_APPLETP_CRL_SERVER_DOWN:
  96     case CSSMERR_APPLETP_CRL_NOT_TRUSTED:
  97     case CSSMERR_APPLETP_CRL_INVALID_ANCHOR_CERT:
  98     case CSSMERR_APPLETP_CRL_POLICY_FAIL:
  99     case CSSMERR_APPLETP_OCSP_BAD_RESPONSE:
 100     case CSSMERR_APPLETP_OCSP_BAD_REQUEST:
 101     case CSSMERR_APPLETP_OCSP_STATUS_UNRECOGNIZED:
 102     case CSSMERR_APPLETP_NETWORK_FAILURE:
 103     case CSSMERR_APPLETP_OCSP_NOT_TRUSTED:
 104     case CSSMERR_APPLETP_OCSP_INVALID_ANCHOR_CERT:
 105     case CSSMERR_APPLETP_OCSP_SIG_ERROR:
 106     case CSSMERR_APPLETP_OCSP_NO_SIGNER:
 107     case CSSMERR_APPLETP_OCSP_RESP_MALFORMED_REQ:
 108     case CSSMERR_APPLETP_OCSP_RESP_INTERNAL_ERR:
 109     case CSSMERR_APPLETP_OCSP_RESP_TRY_LATER:
 110     case CSSMERR_APPLETP_OCSP_RESP_SIG_REQUIRED:
 111     case CSSMERR_APPLETP_OCSP_RESP_UNAUTHORIZED:
 112     case CSSMERR_APPLETP_OCSP_NONCE_MISMATCH:
 113       // We asked for a revocation check, but didn't get it.
 114       return CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
 115
 116     case CSSMERR_APPLETP_SSL_BAD_EXT_KEY_USE:
 117       // TODO(wtc): Should we add CERT_STATUS_WRONG_USAGE?
 118       return CERT_STATUS_INVALID;
 119
 120     case CSSMERR_APPLETP_CRL_BAD_URI:
 121     case CSSMERR_APPLETP_IDP_FAIL:
 122       return CERT_STATUS_INVALID;
 123
 124     case CSSMERR_CSP_UNSUPPORTED_KEY_SIZE:
 125       // Mapping UNSUPPORTED_KEY_SIZE to CERT_STATUS_WEAK_KEY is not strictly
 126       // accurate, as the error may have been returned due to a key size
 127       // that exceeded the maximum supported. However, within
 128       // CertVerifyProcMac::VerifyInternal(), this code should only be
 129       // encountered as a certificate status code, and only when the key size
 130       // is smaller than the minimum required (1024 bits).
 131       return CERT_STATUS_WEAK_KEY;
 132
 133     default: {
 134       // Failure was due to something Chromium doesn't define a
 135       // specific status for (such as basic constraints violation, or
 136       // unknown critical extension)
 137       OSSTATUS_LOG(WARNING, status)
 138           << "Unknown error mapped to CERT_STATUS_INVALID";
 139       return CERT_STATUS_INVALID;
 140     }
 141   }
 142 }
 143
 144 // Creates a series of SecPolicyRefs to be added to a SecTrustRef used to
 145 // validate a certificate for an SSL server. |hostname| contains the name of
 146 // the SSL server that the certificate should be verified against. |flags| is
 147 // a bitwise-OR of VerifyFlags that can further alter how trust is validated,
 148 // such as how revocation is checked. If successful, returns noErr, and
 149 // stores the resultant array of SecPolicyRefs in |policies|.
 150 OSStatus CreateTrustPolicies(const std::string& hostname,
 151                              int flags,
 152                              ScopedCFTypeRef<CFArrayRef>* policies) {
 153   ScopedCFTypeRef<CFMutableArrayRef> local_policies(
 154       CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks));
 155   if (!local_policies)
 156     return memFullErr;
 157
 158   SecPolicyRef ssl_policy;
 159   OSStatus status = x509_util::CreateSSLServerPolicy(hostname, &ssl_policy);
 160   if (status)
 161     return status;
 162   CFArrayAppendValue(local_policies, ssl_policy);
 163   CFRelease(ssl_policy);
 164
 165   // Explicitly add revocation policies, in order to override system
 166   // revocation checking policies and instead respect the application-level
 167   // revocation preference.
 168   status = x509_util::CreateRevocationPolicies(
 169       (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED),
 170       (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY),
 171       local_policies);
 172   if (status)
 173     return status;
 174
 175   policies->reset(local_policies.release());
 176   return noErr;
 177 }
 178
 179 // Saves some information about the certificate chain |cert_chain| in
 180 // |*verify_result|. The caller MUST initialize |*verify_result| before
 181 // calling this function.
 182 void GetCertChainInfo(CFArrayRef cert_chain,
 183                       CSSM_TP_APPLE_EVIDENCE_INFO* chain_info,
 184                       CertVerifyResult* verify_result) {
 185   SecCertificateRef verified_cert = NULL;
 186   std::vector<SecCertificateRef> verified_chain;
 187   for (CFIndex i = 0, count = CFArrayGetCount(cert_chain); i < count; ++i) {
 188     SecCertificateRef chain_cert = reinterpret_cast<SecCertificateRef>(
 189         const_cast<void*>(CFArrayGetValueAtIndex(cert_chain, i)));
 190     if (i == 0) {
 191       verified_cert = chain_cert;
 192     } else {
 193       verified_chain.push_back(chain_cert);
 194     }
 195
 196     if ((chain_info[i].StatusBits & CSSM_CERT_STATUS_IS_IN_ANCHORS) ||
 197         (chain_info[i].StatusBits & CSSM_CERT_STATUS_IS_ROOT)) {
 198       // The current certificate is either in the user's trusted store or is
 199       // a root (self-signed) certificate. Ignore the signature algorithm for
 200       // these certificates, as it is meaningless for security. We allow
 201       // self-signed certificates (i == 0 & IS_ROOT), since we accept that
 202       // any security assertions by such a cert are inherently meaningless.
 203       continue;
 204     }
 205
 206     x509_util::CSSMCachedCertificate cached_cert;
 207     OSStatus status = cached_cert.Init(chain_cert);
 208     if (status)
 209       continue;
 210     x509_util::CSSMFieldValue signature_field;
 211     status = cached_cert.GetField(&CSSMOID_X509V1SignatureAlgorithm,
 212                                   &signature_field);
 213     if (status || !signature_field.field())
 214       continue;
 215     // Match the behaviour of OS X system tools and defensively check that
 216     // sizes are appropriate. This would indicate a critical failure of the
 217     // OS X certificate library, but based on history, it is best to play it
 218     // safe.
 219     const CSSM_X509_ALGORITHM_IDENTIFIER* sig_algorithm =
 220         signature_field.GetAs<CSSM_X509_ALGORITHM_IDENTIFIER>();
 221     if (!sig_algorithm)
 222       continue;
 223
 224     const CSSM_OID* alg_oid = &sig_algorithm->algorithm;
 225     if (CSSMOIDEqual(alg_oid, &CSSMOID_MD2WithRSA)) {
 226       verify_result->has_md2 = true;
 227     } else if (CSSMOIDEqual(alg_oid, &CSSMOID_MD4WithRSA)) {
 228       verify_result->has_md4 = true;
 229     } else if (CSSMOIDEqual(alg_oid, &CSSMOID_MD5WithRSA)) {
 230       verify_result->has_md5 = true;
 231     }
 232   }
 233   if (!verified_cert)
 234     return;
 235
 236   verify_result->verified_cert =
 237       X509Certificate::CreateFromHandle(verified_cert, verified_chain);
 238 }
 239
 240 void AppendPublicKeyHashes(CFArrayRef chain,
 241                            HashValueVector* hashes) {
 242   const CFIndex n = CFArrayGetCount(chain);
 243   for (CFIndex i = 0; i < n; i++) {
 244     SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
 245         const_cast<void*>(CFArrayGetValueAtIndex(chain, i)));
 246
 247     CSSM_DATA cert_data;
 248     OSStatus err = SecCertificateGetData(cert, &cert_data);
 249     DCHECK_EQ(err, noErr);
 250     base::StringPiece der_bytes(reinterpret_cast<const char*>(cert_data.Data),
 251                                cert_data.Length);
 252     base::StringPiece spki_bytes;
 253     if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki_bytes))
 254       continue;
 255
 256     HashValue sha1(HASH_VALUE_SHA1);
 257     CC_SHA1(spki_bytes.data(), spki_bytes.size(), sha1.data());
 258     hashes->push_back(sha1);
 259
 260     HashValue sha256(HASH_VALUE_SHA256);
 261     CC_SHA256(spki_bytes.data(), spki_bytes.size(), sha256.data());
 262     hashes->push_back(sha256);
 263   }
 264 }
 265
 266 bool CheckRevocationWithCRLSet(CFArrayRef chain, CRLSet* crl_set) {
 267   if (CFArrayGetCount(chain) == 0)
 268     return true;
 269
 270   // We iterate from the root certificate down to the leaf, keeping track of
 271   // the issuer's SPKI at each step.
 272   std::string issuer_spki_hash;
 273   for (CFIndex i = CFArrayGetCount(chain) - 1; i >= 0; i--) {
 274     SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
 275         const_cast<void*>(CFArrayGetValueAtIndex(chain, i)));
 276
 277     CSSM_DATA cert_data;
 278     OSStatus err = SecCertificateGetData(cert, &cert_data);
 279     if (err != noErr) {
 280       NOTREACHED();
 281       continue;
 282     }
 283     base::StringPiece der_bytes(reinterpret_cast<const char*>(cert_data.Data),
 284                                 cert_data.Length);
 285     base::StringPiece spki;
 286     if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki)) {
 287       NOTREACHED();
 288       continue;
 289     }
 290
 291     const std::string spki_hash = crypto::SHA256HashString(spki);
 292     x509_util::CSSMCachedCertificate cached_cert;
 293     if (cached_cert.Init(cert) != CSSM_OK) {
 294       NOTREACHED();
 295       continue;
 296     }
 297     x509_util::CSSMFieldValue serial_number;
 298     err = cached_cert.GetField(&CSSMOID_X509V1SerialNumber, &serial_number);
 299     if (err || !serial_number.field()) {
 300       NOTREACHED();
 301       continue;
 302     }
 303
 304     base::StringPiece serial(
 305         reinterpret_cast<const char*>(serial_number.field()->Data),
 306         serial_number.field()->Length);
 307
 308     CRLSet::Result result = crl_set->CheckSPKI(spki_hash);
 309
 310     if (result != CRLSet::REVOKED && !issuer_spki_hash.empty())
 311       result = crl_set->CheckSerial(serial, issuer_spki_hash);
 312
 313     issuer_spki_hash = spki_hash;
 314
 315     switch (result) {
 316       case CRLSet::REVOKED:
 317         return false;
 318       case CRLSet::UNKNOWN:
 319       case CRLSet::GOOD:
 320         continue;
 321       default:
 322         NOTREACHED();
 323         return false;
 324     }
 325   }
 326
 327   return true;
 328 }
 329
 330 // IsIssuedByKnownRoot returns true if the given chain is rooted at a root CA
 331 // that we recognise as a standard root.
 332 // static
 333 bool IsIssuedByKnownRoot(CFArrayRef chain) {
 334   int n = CFArrayGetCount(chain);
 335   if (n < 1)
 336     return false;
 337   SecCertificateRef root_ref = reinterpret_cast<SecCertificateRef>(
 338       const_cast<void*>(CFArrayGetValueAtIndex(chain, n - 1)));
 339   SHA1HashValue hash = X509Certificate::CalculateFingerprint(root_ref);
 340   return IsSHA1HashInSortedArray(
 341       hash, &kKnownRootCertSHA1Hashes[0][0], sizeof(kKnownRootCertSHA1Hashes));
 342 }
 343
 344 // Builds and evaluates a SecTrustRef for the certificate chain contained
 345 // in |cert_array|, using the verification policies in |trust_policies|. On
 346 // success, returns OK, and updates |trust_ref|, |trust_result|,
 347 // |verified_chain|, and |chain_info| with the verification results. On
 348 // failure, no output parameters are modified.
 349 //
 350 // Note: An OK return does not mean that |cert_array| is trusted, merely that
 351 // verification was performed successfully.
 352 //
 353 // This function should only be called while the Mac Security Services lock is
 354 // held.
 355 int BuildAndEvaluateSecTrustRef(CFArrayRef cert_array,
 356                                 CFArrayRef trust_policies,
 357                                 int flags,
 358                                 ScopedCFTypeRef<SecTrustRef>* trust_ref,
 359                                 SecTrustResultType* trust_result,
 360                                 ScopedCFTypeRef<CFArrayRef>* verified_chain,
 361                                 CSSM_TP_APPLE_EVIDENCE_INFO** chain_info) {
 362   SecTrustRef tmp_trust = NULL;
 363   OSStatus status = SecTrustCreateWithCertificates(cert_array, trust_policies,
 364                                                    &tmp_trust);
 365   if (status)
 366     return NetErrorFromOSStatus(status);
 367   ScopedCFTypeRef<SecTrustRef> scoped_tmp_trust(tmp_trust);
 368
 369   if (TestRootCerts::HasInstance()) {
 370     status = TestRootCerts::GetInstance()->FixupSecTrustRef(tmp_trust);
 371     if (status)
 372       return NetErrorFromOSStatus(status);
 373   }
 374
 375   CSSM_APPLE_TP_ACTION_DATA tp_action_data;
 376   memset(&tp_action_data, 0, sizeof(tp_action_data));
 377   tp_action_data.Version = CSSM_APPLE_TP_ACTION_VERSION;
 378   // Allow CSSM to download any missing intermediate certificates if an
 379   // authorityInfoAccess extension or issuerAltName extension is present.
 380   tp_action_data.ActionFlags = CSSM_TP_ACTION_FETCH_CERT_FROM_NET |
 381                                CSSM_TP_ACTION_TRUST_SETTINGS;
 382
 383   // Note: For EV certificates, the Apple TP will handle setting these flags
 384   // as part of EV evaluation.
 385   if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED) {
 386     // Require a positive result from an OCSP responder or a CRL (or both)
 387     // for every certificate in the chain. The Apple TP automatically
 388     // excludes the self-signed root from this requirement. If a certificate
 389     // is missing both a crlDistributionPoints extension and an
 390     // authorityInfoAccess extension with an OCSP responder URL, then we
 391     // will get a kSecTrustResultRecoverableTrustFailure back from
 392     // SecTrustEvaluate(), with a
 393     // CSSMERR_APPLETP_INCOMPLETE_REVOCATION_CHECK error code. In that case,
 394     // we'll set our own result to include
 395     // CERT_STATUS_NO_REVOCATION_MECHANISM. If one or both extensions are
 396     // present, and a check fails (server unavailable, OCSP retry later,
 397     // signature mismatch), then we'll set our own result to include
 398     // CERT_STATUS_UNABLE_TO_CHECK_REVOCATION.
 399     tp_action_data.ActionFlags |= CSSM_TP_ACTION_REQUIRE_REV_PER_CERT;
 400
 401     // Note, even if revocation checking is disabled, SecTrustEvaluate() will
 402     // modify the OCSP options so as to attempt OCSP checking if it believes a
 403     // certificate may chain to an EV root. However, because network fetches
 404     // are disabled in CreateTrustPolicies() when revocation checking is
 405     // disabled, these will only go against the local cache.
 406   }
 407
 408   CFDataRef action_data_ref =
 409       CFDataCreateWithBytesNoCopy(kCFAllocatorDefault,
 410                                   reinterpret_cast<UInt8*>(&tp_action_data),
 411                                   sizeof(tp_action_data), kCFAllocatorNull);
 412   if (!action_data_ref)
 413     return ERR_OUT_OF_MEMORY;
 414   ScopedCFTypeRef<CFDataRef> scoped_action_data_ref(action_data_ref);
 415   status = SecTrustSetParameters(tmp_trust, CSSM_TP_ACTION_DEFAULT,
 416                                  action_data_ref);
 417   if (status)
 418     return NetErrorFromOSStatus(status);
 419
 420   // Verify the certificate. A non-zero result from SecTrustGetResult()
 421   // indicates that some fatal error occurred and the chain couldn't be
 422   // processed, not that the chain contains no errors. We need to examine the
 423   // output of SecTrustGetResult() to determine that.
 424   SecTrustResultType tmp_trust_result;
 425   status = SecTrustEvaluate(tmp_trust, &tmp_trust_result);
 426   if (status)
 427     return NetErrorFromOSStatus(status);
 428   CFArrayRef tmp_verified_chain = NULL;
 429   CSSM_TP_APPLE_EVIDENCE_INFO* tmp_chain_info;
 430   status = SecTrustGetResult(tmp_trust, &tmp_trust_result, &tmp_verified_chain,
 431                              &tmp_chain_info);
 432   if (status)
 433     return NetErrorFromOSStatus(status);
 434
 435   trust_ref->swap(scoped_tmp_trust);
 436   *trust_result = tmp_trust_result;
 437   verified_chain->reset(tmp_verified_chain);
 438   *chain_info = tmp_chain_info;
 439
 440   return OK;
 441 }
 442
 443 // OS X ships with both "GTE CyberTrust Global Root" and "Baltimore CyberTrust
 444 // Root" as part of its trusted root store. However, a cross-certified version
 445 // of the "Baltimore CyberTrust Root" exists that chains to "GTE CyberTrust
 446 // Global Root". When OS X/Security.framework attempts to evaluate such a
 447 // certificate chain, it disregards the "Baltimore CyberTrust Root" that exists
 448 // within Keychain and instead attempts to terminate the chain in the "GTE
 449 // CyberTrust Global Root". However, the GTE root is scheduled to be removed in
 450 // a future OS X update (for sunsetting purposes), and once removed, such
 451 // chains will fail validation, even though a trust anchor still exists.
 452 //
 453 // Rather than over-generalizing a solution that may mask a number of TLS
 454 // misconfigurations, attempt to specifically match the affected
 455 // cross-certified certificate and remove it from certificate chain processing.
 456 bool IsBadBaltimoreGTECertificate(SecCertificateRef cert) {
 457   // Matches the GTE-signed Baltimore CyberTrust Root
 458   // https://cacert.omniroot.com/Baltimore-to-GTE-04-12.pem
 459   static const SHA1HashValue kBadBaltimoreHashNew =
 460     { { 0x4D, 0x34, 0xEA, 0x92, 0x76, 0x4B, 0x3A, 0x31, 0x49, 0x11,
 461         0x99, 0x52, 0xF4, 0x19, 0x30, 0xCA, 0x11, 0x34, 0x83, 0x61 } };
 462   // Matches the legacy GTE-signed Baltimore CyberTrust Root
 463   // https://cacert.omniroot.com/gte-2-2025.pem
 464   static const SHA1HashValue kBadBaltimoreHashOld =
 465     { { 0x54, 0xD8, 0xCB, 0x49, 0x1F, 0xA1, 0x6D, 0xF8, 0x87, 0xDC,
 466         0x94, 0xA9, 0x34, 0xCC, 0x83, 0x6B, 0xDA, 0xA8, 0xA3, 0x69 } };
 467
 468   SHA1HashValue fingerprint = X509Certificate::CalculateFingerprint(cert);
 469
 470   return fingerprint.Equals(kBadBaltimoreHashNew) ||
 471          fingerprint.Equals(kBadBaltimoreHashOld);
 472 }
 473
 474 // Attempts to re-verify |cert_array| after adjusting the inputs to work around
 475 // known issues in OS X. To be used if BuildAndEvaluateSecTrustRef fails to
 476 // return a positive result for verification.
 477 //
 478 // This function should only be called while the Mac Security Services lock is
 479 // held.
 480 void RetrySecTrustEvaluateWithAdjustedChain(
 481     CFArrayRef cert_array,
 482     CFArrayRef trust_policies,
 483     int flags,
 484     ScopedCFTypeRef<SecTrustRef>* trust_ref,
 485     SecTrustResultType* trust_result,
 486     ScopedCFTypeRef<CFArrayRef>* verified_chain,
 487     CSSM_TP_APPLE_EVIDENCE_INFO** chain_info) {
 488   CFIndex count = CFArrayGetCount(*verified_chain);
 489   CFIndex slice_point = 0;
 490
 491   for (CFIndex i = 1; i < count; ++i) {
 492     SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(
 493         const_cast<void*>(CFArrayGetValueAtIndex(*verified_chain, i)));
 494     if (cert == NULL)
 495       return;  // Strange times; can't fix things up.
 496
 497     if (IsBadBaltimoreGTECertificate(cert)) {
 498       slice_point = i;
 499       break;
 500     }
 501   }
 502   if (slice_point == 0)
 503     return;  // Nothing to do.
 504
 505   ScopedCFTypeRef<CFMutableArrayRef> adjusted_cert_array(
 506       CFArrayCreateMutable(NULL, 0, &kCFTypeArrayCallBacks));
 507   // Note: This excludes the certificate at |slice_point|.
 508   CFArrayAppendArray(adjusted_cert_array, cert_array,
 509                      CFRangeMake(0, slice_point));
 510
 511   // Ignore the result; failure will preserve the old verification results.
 512   BuildAndEvaluateSecTrustRef(
 513       adjusted_cert_array, trust_policies, flags, trust_ref, trust_result,
 514       verified_chain, chain_info);
 515 }
 516
 517 }  // namespace
 518
 519 CertVerifyProcMac::CertVerifyProcMac() {}
 520
 521 CertVerifyProcMac::~CertVerifyProcMac() {}
 522
 523 bool CertVerifyProcMac::SupportsAdditionalTrustAnchors() const {
 524   return false;
 525 }
 526
 527 int CertVerifyProcMac::VerifyInternal(
 528     X509Certificate* cert,
 529     const std::string& hostname,
 530     int flags,
 531     CRLSet* crl_set,
 532     const CertificateList& additional_trust_anchors,
 533     CertVerifyResult* verify_result) {
 534   ScopedCFTypeRef<CFArrayRef> trust_policies;
 535   OSStatus status = CreateTrustPolicies(hostname, flags, &trust_policies);
 536   if (status)
 537     return NetErrorFromOSStatus(status);
 538
 539   // Create and configure a SecTrustRef, which takes our certificate(s)
 540   // and our SSL SecPolicyRef. SecTrustCreateWithCertificates() takes an
 541   // array of certificates, the first of which is the certificate we're
 542   // verifying, and the subsequent (optional) certificates are used for
 543   // chain building.
 544   ScopedCFTypeRef<CFArrayRef> cert_array(cert->CreateOSCertChainForCert());
 545
 546   // Serialize all calls that may use the Keychain, to work around various
 547   // issues in OS X 10.6+ with multi-threaded access to Security.framework.
 548   base::AutoLock lock(crypto::GetMacSecurityServicesLock());
 549
 550   ScopedCFTypeRef<SecTrustRef> trust_ref;
 551   SecTrustResultType trust_result = kSecTrustResultDeny;
 552   ScopedCFTypeRef<CFArrayRef> completed_chain;
 553   CSSM_TP_APPLE_EVIDENCE_INFO* chain_info = NULL;
 554
 555   int rv = BuildAndEvaluateSecTrustRef(
 556       cert_array, trust_policies, flags, &trust_ref, &trust_result,
 557       &completed_chain, &chain_info);
 558   if (rv != OK)
 559     return rv;
 560   if (trust_result != kSecTrustResultUnspecified &&
 561       trust_result != kSecTrustResultProceed) {
 562     RetrySecTrustEvaluateWithAdjustedChain(
 563         cert_array, trust_policies, flags, &trust_ref, &trust_result,
 564         &completed_chain, &chain_info);
 565   }
 566
 567   if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED)
 568     verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 569
 570   if (crl_set && !CheckRevocationWithCRLSet(completed_chain, crl_set))
 571     verify_result->cert_status |= CERT_STATUS_REVOKED;
 572
 573   GetCertChainInfo(completed_chain, chain_info, verify_result);
 574
 575   // As of Security Update 2012-002/OS X 10.7.4, when an RSA key < 1024 bits
 576   // is encountered, CSSM returns CSSMERR_TP_VERIFY_ACTION_FAILED and adds
 577   // CSSMERR_CSP_UNSUPPORTED_KEY_SIZE as a certificate status. Avoid mapping
 578   // the CSSMERR_TP_VERIFY_ACTION_FAILED to CERT_STATUS_INVALID if the only
 579   // error was due to an unsupported key size.
 580   bool policy_failed = false;
 581   bool weak_key = false;
 582
 583   // Evaluate the results
 584   OSStatus cssm_result;
 585   switch (trust_result) {
 586     case kSecTrustResultUnspecified:
 587     case kSecTrustResultProceed:
 588       // Certificate chain is valid and trusted ("unspecified" indicates that
 589       // the user has not explicitly set a trust setting)
 590       break;
 591
 592     // According to SecTrust.h, kSecTrustResultConfirm isn't returned on 10.5+,
 593     // and it is marked deprecated in the 10.9 SDK.
 594     case kSecTrustResultDeny:
 595       // Certificate chain is explicitly untrusted.
 596       verify_result->cert_status |= CERT_STATUS_AUTHORITY_INVALID;
 597       break;
 598
 599     case kSecTrustResultRecoverableTrustFailure:
 600       // Certificate chain has a failure that can be overridden by the user.
 601       status = SecTrustGetCssmResultCode(trust_ref, &cssm_result);
 602       if (status)
 603         return NetErrorFromOSStatus(status);
 604       if (cssm_result == CSSMERR_TP_VERIFY_ACTION_FAILED) {
 605         policy_failed = true;
 606       } else {
 607         verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
 608       }
 609       // Walk the chain of error codes in the CSSM_TP_APPLE_EVIDENCE_INFO
 610       // structure which can catch multiple errors from each certificate.
 611       for (CFIndex index = 0, chain_count = CFArrayGetCount(completed_chain);
 612            index < chain_count; ++index) {
 613         if (chain_info[index].StatusBits & CSSM_CERT_STATUS_EXPIRED ||
 614             chain_info[index].StatusBits & CSSM_CERT_STATUS_NOT_VALID_YET)
 615           verify_result->cert_status |= CERT_STATUS_DATE_INVALID;
 616         if (!IsCertStatusError(verify_result->cert_status) &&
 617             chain_info[index].NumStatusCodes == 0) {
 618           LOG(WARNING) << "chain_info[" << index << "].NumStatusCodes is 0"
 619                           ", chain_info[" << index << "].StatusBits is "
 620                        << chain_info[index].StatusBits;
 621         }
 622         for (uint32 status_code_index = 0;
 623              status_code_index < chain_info[index].NumStatusCodes;
 624              ++status_code_index) {
 625           CertStatus mapped_status = CertStatusFromOSStatus(
 626               chain_info[index].StatusCodes[status_code_index]);
 627           if (mapped_status == CERT_STATUS_WEAK_KEY)
 628             weak_key = true;
 629           verify_result->cert_status |= mapped_status;
 630         }
 631       }
 632       if (policy_failed && !weak_key) {
 633         // If CSSMERR_TP_VERIFY_ACTION_FAILED wasn't returned due to a weak
 634         // key, map it back to an appropriate error code.
 635         verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
 636       }
 637       if (!IsCertStatusError(verify_result->cert_status)) {
 638         LOG(ERROR) << "cssm_result=" << cssm_result;
 639         verify_result->cert_status |= CERT_STATUS_INVALID;
 640         NOTREACHED();
 641       }
 642       break;
 643
 644     default:
 645       status = SecTrustGetCssmResultCode(trust_ref, &cssm_result);
 646       if (status)
 647         return NetErrorFromOSStatus(status);
 648       verify_result->cert_status |= CertStatusFromOSStatus(cssm_result);
 649       if (!IsCertStatusError(verify_result->cert_status)) {
 650         LOG(WARNING) << "trust_result=" << trust_result;
 651         verify_result->cert_status |= CERT_STATUS_INVALID;
 652       }
 653       break;
 654   }
 655
 656   // Perform hostname verification independent of SecTrustEvaluate. In order to
 657   // do so, mask off any reported name errors first.
 658   verify_result->cert_status &= ~CERT_STATUS_COMMON_NAME_INVALID;
 659   if (!cert->VerifyNameMatch(hostname,
 660                              &verify_result->common_name_fallback_used)) {
 661     verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
 662   }
 663
 664   // TODO(wtc): Suppress CERT_STATUS_NO_REVOCATION_MECHANISM for now to be
 665   // compatible with Windows, which in turn implements this behavior to be
 666   // compatible with WinHTTP, which doesn't report this error (bug 3004).
 667   verify_result->cert_status &= ~CERT_STATUS_NO_REVOCATION_MECHANISM;
 668
 669   AppendPublicKeyHashes(completed_chain, &verify_result->public_key_hashes);
 670   verify_result->is_issued_by_known_root = IsIssuedByKnownRoot(completed_chain);
 671
 672   if (IsCertStatusError(verify_result->cert_status))
 673     return MapCertStatusToNetError(verify_result->cert_status);
 674
 675   if (flags & CertVerifier::VERIFY_EV_CERT) {
 676     // Determine the certificate's EV status using SecTrustCopyExtendedResult(),
 677     // which is an internal/private API function added in OS X 10.5.7.
 678     // Note: "ExtendedResult" means extended validation results.
 679     CFBundleRef bundle =
 680         CFBundleGetBundleWithIdentifier(CFSTR("com.apple.security"));
 681     if (bundle) {
 682       SecTrustCopyExtendedResultFuncPtr copy_extended_result =
 683           reinterpret_cast<SecTrustCopyExtendedResultFuncPtr>(
 684               CFBundleGetFunctionPointerForName(bundle,
 685                   CFSTR("SecTrustCopyExtendedResult")));
 686       if (copy_extended_result) {
 687         CFDictionaryRef ev_dict_temp = NULL;
 688         status = copy_extended_result(trust_ref, &ev_dict_temp);
 689         ScopedCFTypeRef<CFDictionaryRef> ev_dict(ev_dict_temp);
 690         ev_dict_temp = NULL;
 691         if (status == noErr && ev_dict) {
 692           // In 10.7.3, SecTrustCopyExtendedResult returns noErr and populates
 693           // ev_dict even for non-EV certificates, but only EV certificates
 694           // will cause ev_dict to contain kSecEVOrganizationName. In previous
 695           // releases, SecTrustCopyExtendedResult would only return noErr and
 696           // populate ev_dict for EV certificates, but would always include
 697           // kSecEVOrganizationName in that case, so checking for this key is
 698           // appropriate for all known versions of SecTrustCopyExtendedResult.
 699           // The actual organization name is unneeded here and can be accessed
 700           // through other means. All that matters here is the OS' conception
 701           // of whether or not the certificate is EV.
 702           if (CFDictionaryContainsKey(ev_dict,
 703                                       kSecEVOrganizationName)) {
 704             verify_result->cert_status |= CERT_STATUS_IS_EV;
 705             if (flags & CertVerifier::VERIFY_REV_CHECKING_ENABLED_EV_ONLY)
 706               verify_result->cert_status |= CERT_STATUS_REV_CHECKING_ENABLED;
 707           }
 708         }
 709       }
 710     }
 711   }
 712
 713   return OK;
 714 }
 715
 716 }  // namespace net