net/cert/x509_certificate_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/x509_certificate.h"
   6
   7 #include <CommonCrypto/CommonDigest.h>
   8 #include <CoreServices/CoreServices.h>
   9 #include <Security/Security.h>
  10
  11 #include <cert.h>
  12
  13 #include <vector>
  14
  15 #include "base/lazy_instance.h"
  16 #include "base/logging.h"
  17 #include "base/mac/mac_logging.h"
  18 #include "base/mac/scoped_cftyperef.h"
  19 #include "base/memory/singleton.h"
  20 #include "base/pickle.h"
  21 #include "base/sha1.h"
  22 #include "base/strings/string_piece.h"
  23 #include "base/strings/sys_string_conversions.h"
  24 #include "base/synchronization/lock.h"
  25 #include "crypto/cssm_init.h"
  26 #include "crypto/mac_security_services_lock.h"
  27 #include "crypto/nss_util.h"
  28 #include "net/cert/x509_util_mac.h"
  29
  30 using base::ScopedCFTypeRef;
  31 using base::Time;
  32
  33 namespace net {
  34
  35 namespace {
  36
  37 void GetCertDistinguishedName(
  38     const x509_util::CSSMCachedCertificate& cached_cert,
  39     const CSSM_OID* oid,
  40     CertPrincipal* result) {
  41   x509_util::CSSMFieldValue distinguished_name;
  42   OSStatus status = cached_cert.GetField(oid, &distinguished_name);
  43   if (status || !distinguished_name.field())
  44     return;
  45   result->ParseDistinguishedName(distinguished_name.field()->Data,
  46                                  distinguished_name.field()->Length);
  47 }
  48
  49 bool IsCertIssuerInEncodedList(X509Certificate::OSCertHandle cert_handle,
  50                                const std::vector<std::string>& issuers) {
  51   x509_util::CSSMCachedCertificate cached_cert;
  52   if (cached_cert.Init(cert_handle) != CSSM_OK)
  53     return false;
  54
  55   x509_util::CSSMFieldValue distinguished_name;
  56   OSStatus status = cached_cert.GetField(&CSSMOID_X509V1IssuerNameStd,
  57                                          &distinguished_name);
  58   if (status || !distinguished_name.field())
  59     return false;
  60
  61   base::StringPiece name_piece(
  62       reinterpret_cast<const char*>(distinguished_name.field()->Data),
  63       static_cast<size_t>(distinguished_name.field()->Length));
  64
  65   for (std::vector<std::string>::const_iterator it = issuers.begin();
  66        it != issuers.end(); ++it) {
  67     base::StringPiece issuer_piece(*it);
  68     if (name_piece == issuer_piece)
  69       return true;
  70   }
  71
  72   return false;
  73 }
  74
  75 void GetCertDateForOID(const x509_util::CSSMCachedCertificate& cached_cert,
  76                        const CSSM_OID* oid,
  77                        Time* result) {
  78   *result = Time::Time();
  79
  80   x509_util::CSSMFieldValue field;
  81   OSStatus status = cached_cert.GetField(oid, &field);
  82   if (status)
  83     return;
  84
  85   const CSSM_X509_TIME* x509_time = field.GetAs<CSSM_X509_TIME>();
  86   if (x509_time->timeType != BER_TAG_UTC_TIME &&
  87       x509_time->timeType != BER_TAG_GENERALIZED_TIME) {
  88     LOG(ERROR) << "Unsupported date/time format "
  89                << x509_time->timeType;
  90     return;
  91   }
  92
  93   base::StringPiece time_string(
  94       reinterpret_cast<const char*>(x509_time->time.Data),
  95       x509_time->time.Length);
  96   CertDateFormat format = x509_time->timeType == BER_TAG_UTC_TIME ?
  97       CERT_DATE_FORMAT_UTC_TIME : CERT_DATE_FORMAT_GENERALIZED_TIME;
  98   if (!ParseCertificateDate(time_string, format, result))
  99     LOG(ERROR) << "Invalid certificate date/time " << time_string;
 100 }
 101
 102 std::string GetCertSerialNumber(
 103     const x509_util::CSSMCachedCertificate& cached_cert) {
 104   x509_util::CSSMFieldValue serial_number;
 105   OSStatus status = cached_cert.GetField(&CSSMOID_X509V1SerialNumber,
 106                                          &serial_number);
 107   if (status || !serial_number.field())
 108     return std::string();
 109
 110   return std::string(
 111       reinterpret_cast<const char*>(serial_number.field()->Data),
 112       serial_number.field()->Length);
 113 }
 114
 115 // Returns true if |purpose| is listed as allowed in |usage|. This
 116 // function also considers the "Any" purpose. If the attribute is
 117 // present and empty, we return false.
 118 bool ExtendedKeyUsageAllows(const CE_ExtendedKeyUsage* usage,
 119                             const CSSM_OID* purpose) {
 120   for (unsigned p = 0; p < usage->numPurposes; ++p) {
 121     if (CSSMOIDEqual(&usage->purposes[p], purpose))
 122       return true;
 123     if (CSSMOIDEqual(&usage->purposes[p], &CSSMOID_ExtendedKeyUsageAny))
 124       return true;
 125   }
 126   return false;
 127 }
 128
 129 // Test that a given |cert_handle| is actually a valid X.509 certificate, and
 130 // return true if it is.
 131 //
 132 // On OS X, SecCertificateCreateFromData() does not return any errors if
 133 // called with invalid data, as long as data is present. The actual decoding
 134 // of the certificate does not happen until an API that requires a CSSM
 135 // handle is called. While SecCertificateGetCLHandle is the most likely
 136 // candidate, as it performs the parsing, it does not check whether the
 137 // parsing was actually successful. Instead, SecCertificateGetSubject is
 138 // used (supported since 10.3), as a means to check that the certificate
 139 // parsed as a valid X.509 certificate.
 140 bool IsValidOSCertHandle(SecCertificateRef cert_handle) {
 141   const CSSM_X509_NAME* sanity_check = NULL;
 142   OSStatus status = SecCertificateGetSubject(cert_handle, &sanity_check);
 143   return status == noErr && sanity_check;
 144 }
 145
 146 // Parses |data| of length |length|, attempting to decode it as the specified
 147 // |format|. If |data| is in the specified format, any certificates contained
 148 // within are stored into |output|.
 149 void AddCertificatesFromBytes(const char* data, size_t length,
 150                               SecExternalFormat format,
 151                               X509Certificate::OSCertHandles* output) {
 152   SecExternalFormat input_format = format;
 153   ScopedCFTypeRef<CFDataRef> local_data(CFDataCreateWithBytesNoCopy(
 154       kCFAllocatorDefault, reinterpret_cast<const UInt8*>(data), length,
 155       kCFAllocatorNull));
 156
 157   CFArrayRef items = NULL;
 158   OSStatus status;
 159   {
 160     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
 161     status = SecKeychainItemImport(local_data, NULL, &input_format,
 162                                    NULL, 0, NULL, NULL, &items);
 163   }
 164
 165   if (status) {
 166     OSSTATUS_DLOG(WARNING, status)
 167         << "Unable to import items from data of length " << length;
 168     return;
 169   }
 170
 171   ScopedCFTypeRef<CFArrayRef> scoped_items(items);
 172   CFTypeID cert_type_id = SecCertificateGetTypeID();
 173
 174   for (CFIndex i = 0; i < CFArrayGetCount(items); ++i) {
 175     SecKeychainItemRef item = reinterpret_cast<SecKeychainItemRef>(
 176         const_cast<void*>(CFArrayGetValueAtIndex(items, i)));
 177
 178     // While inputFormat implies only certificates will be imported, if/when
 179     // other formats (eg: PKCS#12) are supported, this may also include
 180     // private keys or other items types, so filter appropriately.
 181     if (CFGetTypeID(item) == cert_type_id) {
 182       SecCertificateRef cert = reinterpret_cast<SecCertificateRef>(item);
 183       // OS X ignores |input_format| if it detects that |local_data| is PEM
 184       // encoded, attempting to decode data based on internal rules for PEM
 185       // block headers. If a PKCS#7 blob is encoded with a PEM block of
 186       // CERTIFICATE, OS X 10.5 will return a single, invalid certificate
 187       // based on the decoded data. If this happens, the certificate should
 188       // not be included in |output|. Because |output| is empty,
 189       // CreateCertificateListfromBytes will use PEMTokenizer to decode the
 190       // data. When called again with the decoded data, OS X will honor
 191       // |input_format|, causing decode to succeed. On OS X 10.6, the data
 192       // is properly decoded as a PKCS#7, whether PEM or not, which avoids
 193       // the need to fallback to internal decoding.
 194       if (IsValidOSCertHandle(cert)) {
 195         CFRetain(cert);
 196         output->push_back(cert);
 197       }
 198     }
 199   }
 200 }
 201
 202 struct CSSMOIDString {
 203   const CSSM_OID* oid_;
 204   std::string string_;
 205 };
 206
 207 typedef std::vector<CSSMOIDString> CSSMOIDStringVector;
 208
 209 class ScopedCertName {
 210  public:
 211   explicit ScopedCertName(CERTName* name) : name_(name) { }
 212   ~ScopedCertName() {
 213     if (name_) CERT_DestroyName(name_);
 214   }
 215   operator CERTName*() { return name_; }
 216
 217  private:
 218   CERTName* name_;
 219 };
 220
 221 class ScopedEncodedCertResults {
 222  public:
 223   explicit ScopedEncodedCertResults(CSSM_TP_RESULT_SET* results)
 224       : results_(results) { }
 225   ~ScopedEncodedCertResults() {
 226     if (results_) {
 227       CSSM_ENCODED_CERT* encCert =
 228           reinterpret_cast<CSSM_ENCODED_CERT*>(results_->Results);
 229       for (uint32 i = 0; i < results_->NumberOfResults; i++) {
 230         crypto::CSSMFree(encCert[i].CertBlob.Data);
 231       }
 232       crypto::CSSMFree(results_->Results);
 233       crypto::CSSMFree(results_);
 234     }
 235   }
 236
 237  private:
 238   CSSM_TP_RESULT_SET* results_;
 239 };
 240
 241 }  // namespace
 242
 243 void X509Certificate::Initialize() {
 244   x509_util::CSSMCachedCertificate cached_cert;
 245   if (cached_cert.Init(cert_handle_) == CSSM_OK) {
 246     GetCertDistinguishedName(cached_cert, &CSSMOID_X509V1SubjectNameStd,
 247                              &subject_);
 248     GetCertDistinguishedName(cached_cert, &CSSMOID_X509V1IssuerNameStd,
 249                              &issuer_);
 250     GetCertDateForOID(cached_cert, &CSSMOID_X509V1ValidityNotBefore,
 251                       &valid_start_);
 252     GetCertDateForOID(cached_cert, &CSSMOID_X509V1ValidityNotAfter,
 253                       &valid_expiry_);
 254     serial_number_ = GetCertSerialNumber(cached_cert);
 255   }
 256
 257   fingerprint_ = CalculateFingerprint(cert_handle_);
 258   ca_fingerprint_ = CalculateCAFingerprint(intermediate_ca_certs_);
 259 }
 260
 261 bool X509Certificate::IsIssuedByEncoded(
 262     const std::vector<std::string>& valid_issuers) {
 263   if (IsCertIssuerInEncodedList(cert_handle_, valid_issuers))
 264     return true;
 265
 266   for (OSCertHandles::iterator it = intermediate_ca_certs_.begin();
 267        it != intermediate_ca_certs_.end(); ++it) {
 268     if (IsCertIssuerInEncodedList(*it, valid_issuers))
 269       return true;
 270   }
 271   return false;
 272 }
 273
 274 void X509Certificate::GetSubjectAltName(
 275     std::vector<std::string>* dns_names,
 276     std::vector<std::string>* ip_addrs) const {
 277   if (dns_names)
 278     dns_names->clear();
 279   if (ip_addrs)
 280     ip_addrs->clear();
 281
 282   x509_util::CSSMCachedCertificate cached_cert;
 283   OSStatus status = cached_cert.Init(cert_handle_);
 284   if (status)
 285     return;
 286   x509_util::CSSMFieldValue subject_alt_name;
 287   status = cached_cert.GetField(&CSSMOID_SubjectAltName, &subject_alt_name);
 288   if (status || !subject_alt_name.field())
 289     return;
 290   const CSSM_X509_EXTENSION* cssm_ext =
 291       subject_alt_name.GetAs<CSSM_X509_EXTENSION>();
 292   if (!cssm_ext || !cssm_ext->value.parsedValue)
 293     return;
 294   const CE_GeneralNames* alt_name =
 295       reinterpret_cast<const CE_GeneralNames*>(cssm_ext->value.parsedValue);
 296
 297   for (size_t name = 0; name < alt_name->numNames; ++name) {
 298     const CE_GeneralName& name_struct = alt_name->generalName[name];
 299     const CSSM_DATA& name_data = name_struct.name;
 300     // DNSName and IPAddress are encoded as IA5String and OCTET STRINGs
 301     // respectively, both of which can be byte copied from
 302     // CSSM_DATA::data into the appropriate output vector.
 303     if (dns_names && name_struct.nameType == GNT_DNSName) {
 304       dns_names->push_back(std::string(
 305           reinterpret_cast<const char*>(name_data.Data),
 306           name_data.Length));
 307     } else if (ip_addrs && name_struct.nameType == GNT_IPAddress) {
 308       ip_addrs->push_back(std::string(
 309           reinterpret_cast<const char*>(name_data.Data),
 310           name_data.Length));
 311     }
 312   }
 313 }
 314
 315 // static
 316 bool X509Certificate::GetDEREncoded(X509Certificate::OSCertHandle cert_handle,
 317                                     std::string* encoded) {
 318   CSSM_DATA der_data;
 319   if (SecCertificateGetData(cert_handle, &der_data) != noErr)
 320     return false;
 321   encoded->assign(reinterpret_cast<char*>(der_data.Data),
 322                   der_data.Length);
 323   return true;
 324 }
 325
 326 // static
 327 bool X509Certificate::IsSameOSCert(X509Certificate::OSCertHandle a,
 328                                    X509Certificate::OSCertHandle b) {
 329   DCHECK(a && b);
 330   if (a == b)
 331     return true;
 332   if (CFEqual(a, b))
 333     return true;
 334   CSSM_DATA a_data, b_data;
 335   return SecCertificateGetData(a, &a_data) == noErr &&
 336       SecCertificateGetData(b, &b_data) == noErr &&
 337       a_data.Length == b_data.Length &&
 338       memcmp(a_data.Data, b_data.Data, a_data.Length) == 0;
 339 }
 340
 341 // static
 342 X509Certificate::OSCertHandle X509Certificate::CreateOSCertHandleFromBytes(
 343     const char* data, int length) {
 344   CSSM_DATA cert_data;
 345   cert_data.Data = const_cast<uint8*>(reinterpret_cast<const uint8*>(data));
 346   cert_data.Length = length;
 347
 348   OSCertHandle cert_handle = NULL;
 349   OSStatus status = SecCertificateCreateFromData(&cert_data,
 350                                                  CSSM_CERT_X_509v3,
 351                                                  CSSM_CERT_ENCODING_DER,
 352                                                  &cert_handle);
 353   if (status != noErr)
 354     return NULL;
 355   if (!IsValidOSCertHandle(cert_handle)) {
 356     CFRelease(cert_handle);
 357     return NULL;
 358   }
 359   return cert_handle;
 360 }
 361
 362 // static
 363 X509Certificate::OSCertHandles X509Certificate::CreateOSCertHandlesFromBytes(
 364     const char* data, int length, Format format) {
 365   OSCertHandles results;
 366
 367   switch (format) {
 368     case FORMAT_SINGLE_CERTIFICATE: {
 369       OSCertHandle handle = CreateOSCertHandleFromBytes(data, length);
 370       if (handle)
 371         results.push_back(handle);
 372       break;
 373     }
 374     case FORMAT_PKCS7:
 375       AddCertificatesFromBytes(data, length, kSecFormatPKCS7, &results);
 376       break;
 377     default:
 378       NOTREACHED() << "Certificate format " << format << " unimplemented";
 379       break;
 380   }
 381
 382   return results;
 383 }
 384
 385 // static
 386 X509Certificate::OSCertHandle X509Certificate::DupOSCertHandle(
 387     OSCertHandle handle) {
 388   if (!handle)
 389     return NULL;
 390   return reinterpret_cast<OSCertHandle>(const_cast<void*>(CFRetain(handle)));
 391 }
 392
 393 // static
 394 void X509Certificate::FreeOSCertHandle(OSCertHandle cert_handle) {
 395   CFRelease(cert_handle);
 396 }
 397
 398 // static
 399 SHA1HashValue X509Certificate::CalculateFingerprint(
 400     OSCertHandle cert) {
 401   SHA1HashValue sha1;
 402   memset(sha1.data, 0, sizeof(sha1.data));
 403
 404   CSSM_DATA cert_data;
 405   OSStatus status = SecCertificateGetData(cert, &cert_data);
 406   if (status)
 407     return sha1;
 408
 409   DCHECK(cert_data.Data);
 410   DCHECK_NE(cert_data.Length, 0U);
 411
 412   CC_SHA1(cert_data.Data, cert_data.Length, sha1.data);
 413
 414   return sha1;
 415 }
 416
 417 // static
 418 SHA1HashValue X509Certificate::CalculateCAFingerprint(
 419     const OSCertHandles& intermediates) {
 420   SHA1HashValue sha1;
 421   memset(sha1.data, 0, sizeof(sha1.data));
 422
 423   // The CC_SHA(3cc) man page says all CC_SHA1_xxx routines return 1, so
 424   // we don't check their return values.
 425   CC_SHA1_CTX sha1_ctx;
 426   CC_SHA1_Init(&sha1_ctx);
 427   CSSM_DATA cert_data;
 428   for (size_t i = 0; i < intermediates.size(); ++i) {
 429     OSStatus status = SecCertificateGetData(intermediates[i], &cert_data);
 430     if (status)
 431       return sha1;
 432     CC_SHA1_Update(&sha1_ctx, cert_data.Data, cert_data.Length);
 433   }
 434   CC_SHA1_Final(sha1.data, &sha1_ctx);
 435
 436   return sha1;
 437 }
 438
 439 bool X509Certificate::SupportsSSLClientAuth() const {
 440   x509_util::CSSMCachedCertificate cached_cert;
 441   OSStatus status = cached_cert.Init(cert_handle_);
 442   if (status)
 443     return false;
 444
 445   // RFC5280 says to take the intersection of the two extensions.
 446   //
 447   // Our underlying crypto libraries don't expose
 448   // ClientCertificateType, so for now we will not support fixed
 449   // Diffie-Hellman mechanisms. For rsa_sign, we need the
 450   // digitalSignature bit.
 451   //
 452   // In particular, if a key has the nonRepudiation bit and not the
 453   // digitalSignature one, we will not offer it to the user.
 454   x509_util::CSSMFieldValue key_usage;
 455   status = cached_cert.GetField(&CSSMOID_KeyUsage, &key_usage);
 456   if (status == CSSM_OK && key_usage.field()) {
 457     const CSSM_X509_EXTENSION* ext = key_usage.GetAs<CSSM_X509_EXTENSION>();
 458     const CE_KeyUsage* key_usage_value =
 459         reinterpret_cast<const CE_KeyUsage*>(ext->value.parsedValue);
 460     if (!((*key_usage_value) & CE_KU_DigitalSignature))
 461       return false;
 462   }
 463
 464   status = cached_cert.GetField(&CSSMOID_ExtendedKeyUsage, &key_usage);
 465   if (status == CSSM_OK && key_usage.field()) {
 466     const CSSM_X509_EXTENSION* ext = key_usage.GetAs<CSSM_X509_EXTENSION>();
 467     const CE_ExtendedKeyUsage* ext_key_usage =
 468         reinterpret_cast<const CE_ExtendedKeyUsage*>(ext->value.parsedValue);
 469     if (!ExtendedKeyUsageAllows(ext_key_usage, &CSSMOID_ClientAuth))
 470       return false;
 471   }
 472   return true;
 473 }
 474
 475 CFArrayRef X509Certificate::CreateOSCertChainForCert() const {
 476   CFMutableArrayRef cert_list =
 477       CFArrayCreateMutable(kCFAllocatorDefault, 0,
 478                            &kCFTypeArrayCallBacks);
 479   if (!cert_list)
 480     return NULL;
 481
 482   CFArrayAppendValue(cert_list, os_cert_handle());
 483   for (size_t i = 0; i < intermediate_ca_certs_.size(); ++i)
 484     CFArrayAppendValue(cert_list, intermediate_ca_certs_[i]);
 485
 486   return cert_list;
 487 }
 488
 489 // static
 490 X509Certificate::OSCertHandle
 491 X509Certificate::ReadOSCertHandleFromPickle(PickleIterator* pickle_iter) {
 492   const char* data;
 493   int length;
 494   if (!pickle_iter->ReadData(&data, &length))
 495     return NULL;
 496
 497   return CreateOSCertHandleFromBytes(data, length);
 498 }
 499
 500 // static
 501 bool X509Certificate::WriteOSCertHandleToPickle(OSCertHandle cert_handle,
 502                                                 Pickle* pickle) {
 503   CSSM_DATA cert_data;
 504   OSStatus status = SecCertificateGetData(cert_handle, &cert_data);
 505   if (status)
 506     return false;
 507
 508   return pickle->WriteData(reinterpret_cast<char*>(cert_data.Data),
 509                            cert_data.Length);
 510 }
 511
 512 // static
 513 void X509Certificate::GetPublicKeyInfo(OSCertHandle cert_handle,
 514                                        size_t* size_bits,
 515                                        PublicKeyType* type) {
 516   // Since we might fail, set the output parameters to default values first.
 517   *type = kPublicKeyTypeUnknown;
 518   *size_bits = 0;
 519
 520   SecKeyRef key;
 521   OSStatus status = SecCertificateCopyPublicKey(cert_handle, &key);
 522   if (status) {
 523     NOTREACHED() << "SecCertificateCopyPublicKey failed: " << status;
 524     return;
 525   }
 526   ScopedCFTypeRef<SecKeyRef> scoped_key(key);
 527
 528   const CSSM_KEY* cssm_key;
 529   status = SecKeyGetCSSMKey(key, &cssm_key);
 530   if (status) {
 531     NOTREACHED() << "SecKeyGetCSSMKey failed: " << status;
 532     return;
 533   }
 534
 535   *size_bits = cssm_key->KeyHeader.LogicalKeySizeInBits;
 536
 537   switch (cssm_key->KeyHeader.AlgorithmId) {
 538     case CSSM_ALGID_RSA:
 539       *type = kPublicKeyTypeRSA;
 540       break;
 541     case CSSM_ALGID_DSA:
 542       *type = kPublicKeyTypeDSA;
 543       break;
 544     case CSSM_ALGID_ECDSA:
 545       *type = kPublicKeyTypeECDSA;
 546       break;
 547     case CSSM_ALGID_DH:
 548       *type = kPublicKeyTypeDH;
 549       break;
 550     default:
 551       *type = kPublicKeyTypeUnknown;
 552       *size_bits = 0;
 553       break;
 554   }
 555 }
 556
 557 }  // namespace net