net/ssl/openssl_platform_key_mac.cc

   1 // Copyright 2014 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/ssl/openssl_platform_key.h"
   6
   7 #include <openssl/ec_key.h>
   8 #include <openssl/err.h>
   9 #include <openssl/engine.h>
  10 #include <openssl/evp.h>
  11 #include <openssl/rsa.h>
  12
  13 #include <Security/cssm.h>
  14 #include <Security/SecBase.h>
  15 #include <Security/SecCertificate.h>
  16 #include <Security/SecIdentity.h>
  17 #include <Security/SecKey.h>
  18
  19 #include "base/lazy_instance.h"
  20 #include "base/location.h"
  21 #include "base/logging.h"
  22 #include "base/mac/mac_logging.h"
  23 #include "base/mac/scoped_cftyperef.h"
  24 #include "base/memory/scoped_policy.h"
  25 #include "base/memory/scoped_ptr.h"
  26 #include "base/synchronization/lock.h"
  27 #include "crypto/mac_security_services_lock.h"
  28 #include "net/base/net_errors.h"
  29 #include "net/cert/x509_certificate.h"
  30 #include "net/ssl/openssl_ssl_util.h"
  31
  32 namespace net {
  33
  34 namespace {
  35
  36 class ScopedCSSM_CC_HANDLE {
  37  public:
  38   ScopedCSSM_CC_HANDLE() : handle_(0) {
  39   }
  40
  41   ~ScopedCSSM_CC_HANDLE() {
  42     reset();
  43   }
  44
  45   CSSM_CC_HANDLE get() const {
  46     return handle_;
  47   }
  48
  49   void reset() {
  50     if (handle_)
  51       CSSM_DeleteContext(handle_);
  52     handle_ = 0;
  53   }
  54
  55   CSSM_CC_HANDLE* InitializeInto() {
  56     reset();
  57     return &handle_;
  58   }
  59  private:
  60   CSSM_CC_HANDLE handle_;
  61
  62   DISALLOW_COPY_AND_ASSIGN(ScopedCSSM_CC_HANDLE);
  63 };
  64
  65 // Looks up the private key for |certificate| in KeyChain and returns
  66 // a SecKeyRef or NULL on failure. The caller takes ownership of the
  67 // result.
  68 SecKeyRef FetchSecKeyRefForCertificate(const X509Certificate* certificate) {
  69   OSStatus status;
  70   base::ScopedCFTypeRef<SecIdentityRef> identity;
  71   {
  72     base::AutoLock lock(crypto::GetMacSecurityServicesLock());
  73     status = SecIdentityCreateWithCertificate(
  74         NULL, certificate->os_cert_handle(), identity.InitializeInto());
  75   }
  76   if (status != noErr) {
  77     OSSTATUS_LOG(WARNING, status);
  78     return NULL;
  79   }
  80
  81   base::ScopedCFTypeRef<SecKeyRef> private_key;
  82   status = SecIdentityCopyPrivateKey(identity, private_key.InitializeInto());
  83   if (status != noErr) {
  84     OSSTATUS_LOG(WARNING, status);
  85     return NULL;
  86   }
  87
  88   return private_key.release();
  89 }
  90
  91 extern const RSA_METHOD mac_rsa_method;
  92 extern const ECDSA_METHOD mac_ecdsa_method;
  93
  94 // KeyExData contains the data that is contained in the EX_DATA of the
  95 // RSA and ECDSA objects that are created to wrap Mac system keys.
  96 struct KeyExData {
  97   KeyExData(SecKeyRef key, const CSSM_KEY* cssm_key)
  98       : key(key, base::scoped_policy::RETAIN), cssm_key(cssm_key) {}
  99
 100   base::ScopedCFTypeRef<SecKeyRef> key;
 101   const CSSM_KEY* cssm_key;
 102 };
 103
 104 // ExDataDup is called when one of the RSA or EC_KEY objects is
 105 // duplicated. This is not supported and should never happen.
 106 int ExDataDup(CRYPTO_EX_DATA* to,
 107               const CRYPTO_EX_DATA* from,
 108               void** from_d,
 109               int idx,
 110               long argl,
 111               void* argp) {
 112   CHECK_EQ((void*)NULL, *from_d);
 113   return 0;
 114 }
 115
 116 // ExDataFree is called when one of the RSA or EC_KEY objects is freed.
 117 void ExDataFree(void* parent,
 118                 void* ptr,
 119                 CRYPTO_EX_DATA* ex_data,
 120                 int idx,
 121                 long argl, void* argp) {
 122   KeyExData* data = reinterpret_cast<KeyExData*>(ptr);
 123   delete data;
 124 }
 125
 126 // BoringSSLEngine is a BoringSSL ENGINE that implements RSA and ECDSA
 127 // by forwarding the requested operations to Apple's CSSM
 128 // implementation.
 129 class BoringSSLEngine {
 130  public:
 131   BoringSSLEngine()
 132       : rsa_index_(RSA_get_ex_new_index(0 /* argl */,
 133                                         NULL /* argp */,
 134                                         NULL /* new_func */,
 135                                         ExDataDup,
 136                                         ExDataFree)),
 137         ec_key_index_(EC_KEY_get_ex_new_index(0 /* argl */,
 138                                               NULL /* argp */,
 139                                               NULL /* new_func */,
 140                                               ExDataDup,
 141                                               ExDataFree)),
 142         engine_(ENGINE_new()) {
 143     ENGINE_set_RSA_method(
 144         engine_, &mac_rsa_method, sizeof(mac_rsa_method));
 145     ENGINE_set_ECDSA_method(
 146         engine_, &mac_ecdsa_method, sizeof(mac_ecdsa_method));
 147   }
 148
 149   int rsa_ex_index() const { return rsa_index_; }
 150   int ec_key_ex_index() const { return ec_key_index_; }
 151
 152   const ENGINE* engine() const { return engine_; }
 153
 154  private:
 155   const int rsa_index_;
 156   const int ec_key_index_;
 157   ENGINE* const engine_;
 158 };
 159
 160 base::LazyInstance<BoringSSLEngine>::Leaky global_boringssl_engine =
 161     LAZY_INSTANCE_INITIALIZER;
 162
 163 // Helper function for making a signature.
 164
 165 // MakeCSSMSignature uses the key information in |ex_data| to sign the
 166 // |in_len| bytes pointed by |in|. It writes up to |max_out| bytes
 167 // into the buffer pointed to by |out|, setting |*out_len| to the
 168 // number of bytes written. It returns 1 on success and 0 on failure.
 169 int MakeCSSMSignature(const KeyExData* ex_data,
 170                       size_t* out_len,
 171                       uint8_t* out,
 172                       size_t max_out,
 173                       const uint8_t* in,
 174                       size_t in_len) {
 175   CSSM_CSP_HANDLE csp_handle;
 176   OSStatus status = SecKeyGetCSPHandle(ex_data->key.get(), &csp_handle);
 177   if (status != noErr) {
 178     OSSTATUS_LOG(WARNING, status);
 179     OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
 180     return 0;
 181   }
 182
 183   const CSSM_ACCESS_CREDENTIALS* cssm_creds = NULL;
 184   status = SecKeyGetCredentials(ex_data->key.get(), CSSM_ACL_AUTHORIZATION_SIGN,
 185                                 kSecCredentialTypeDefault, &cssm_creds);
 186   if (status != noErr) {
 187     OSSTATUS_LOG(WARNING, status);
 188     OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
 189     return 0;
 190   }
 191
 192   ScopedCSSM_CC_HANDLE cssm_signature;
 193   if (CSSM_CSP_CreateSignatureContext(
 194           csp_handle, ex_data->cssm_key->KeyHeader.AlgorithmId, cssm_creds,
 195           ex_data->cssm_key, cssm_signature.InitializeInto()) != CSSM_OK) {
 196     OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
 197     return 0;
 198   }
 199
 200   if (ex_data->cssm_key->KeyHeader.AlgorithmId == CSSM_ALGID_RSA) {
 201     // Set RSA blinding.
 202     CSSM_CONTEXT_ATTRIBUTE blinding_attr;
 203     blinding_attr.AttributeType   = CSSM_ATTRIBUTE_RSA_BLINDING;
 204     blinding_attr.AttributeLength = sizeof(uint32);
 205     blinding_attr.Attribute.Uint32 = 1;
 206     if (CSSM_UpdateContextAttributes(
 207             cssm_signature.get(), 1, &blinding_attr) != CSSM_OK) {
 208       OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
 209       return 0;
 210     }
 211   }
 212
 213   CSSM_DATA hash_data;
 214   hash_data.Length = in_len;
 215   hash_data.Data = const_cast<uint8*>(in);
 216
 217   CSSM_DATA signature_data;
 218   signature_data.Length = max_out;
 219   signature_data.Data = out;
 220
 221   if (CSSM_SignData(cssm_signature.get(), &hash_data, 1,
 222                     CSSM_ALGID_NONE, &signature_data) != CSSM_OK) {
 223     OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
 224     return 0;
 225   }
 226
 227   *out_len = signature_data.Length;
 228   return 1;
 229 }
 230
 231 // Custom RSA_METHOD that uses the platform APIs for signing.
 232
 233 const KeyExData* RsaGetExData(const RSA* rsa) {
 234   return reinterpret_cast<const KeyExData*>(
 235       RSA_get_ex_data(rsa, global_boringssl_engine.Get().rsa_ex_index()));
 236 }
 237
 238 size_t RsaMethodSize(const RSA *rsa) {
 239   const KeyExData *ex_data = RsaGetExData(rsa);
 240   return (ex_data->cssm_key->KeyHeader.LogicalKeySizeInBits + 7) / 8;
 241 }
 242
 243 int RsaMethodEncrypt(RSA* rsa,
 244                      size_t* out_len,
 245                      uint8_t* out,
 246                      size_t max_out,
 247                      const uint8_t* in,
 248                      size_t in_len,
 249                      int padding) {
 250   NOTIMPLEMENTED();
 251   OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_UNKNOWN_ALGORITHM_TYPE);
 252   return 0;
 253 }
 254
 255 int RsaMethodSignRaw(RSA* rsa,
 256                      size_t* out_len,
 257                      uint8_t* out,
 258                      size_t max_out,
 259                      const uint8_t* in,
 260                      size_t in_len,
 261                      int padding) {
 262   // Only support PKCS#1 padding.
 263   DCHECK_EQ(RSA_PKCS1_PADDING, padding);
 264   if (padding != RSA_PKCS1_PADDING) {
 265     OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_UNKNOWN_PADDING_TYPE);
 266     return 0;
 267   }
 268
 269   const KeyExData *ex_data = RsaGetExData(rsa);
 270   if (!ex_data) {
 271     OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
 272     return 0;
 273   }
 274   DCHECK_EQ(CSSM_ALGID_RSA, ex_data->cssm_key->KeyHeader.AlgorithmId);
 275
 276   return MakeCSSMSignature(ex_data, out_len, out, max_out, in, in_len);
 277 }
 278
 279 int RsaMethodDecrypt(RSA* rsa,
 280                      size_t* out_len,
 281                      uint8_t* out,
 282                      size_t max_out,
 283                      const uint8_t* in,
 284                      size_t in_len,
 285                      int padding) {
 286   NOTIMPLEMENTED();
 287   OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_UNKNOWN_ALGORITHM_TYPE);
 288   return 0;
 289 }
 290
 291 int RsaMethodVerifyRaw(RSA* rsa,
 292                        size_t* out_len,
 293                        uint8_t* out,
 294                        size_t max_out,
 295                        const uint8_t* in,
 296                        size_t in_len,
 297                        int padding) {
 298   NOTIMPLEMENTED();
 299   OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_UNKNOWN_ALGORITHM_TYPE);
 300   return 0;
 301 }
 302
 303 const RSA_METHOD mac_rsa_method = {
 304     {
 305      0 /* references */,
 306      1 /* is_static */
 307     } /* common */,
 308     NULL /* app_data */,
 309
 310     NULL /* init */,
 311     NULL /* finish */,
 312     RsaMethodSize,
 313     NULL /* sign */,
 314     NULL /* verify */,
 315     RsaMethodEncrypt,
 316     RsaMethodSignRaw,
 317     RsaMethodDecrypt,
 318     RsaMethodVerifyRaw,
 319     NULL /* private_transform */,
 320     NULL /* mod_exp */,
 321     NULL /* bn_mod_exp */,
 322     RSA_FLAG_OPAQUE,
 323     NULL /* keygen */,
 324 };
 325
 326 crypto::ScopedEVP_PKEY CreateRSAWrapper(SecKeyRef key,
 327                                         const CSSM_KEY* cssm_key) {
 328   crypto::ScopedRSA rsa(
 329       RSA_new_method(global_boringssl_engine.Get().engine()));
 330   if (!rsa)
 331     return crypto::ScopedEVP_PKEY();
 332
 333   RSA_set_ex_data(
 334       rsa.get(), global_boringssl_engine.Get().rsa_ex_index(),
 335       new KeyExData(key, cssm_key));
 336
 337   crypto::ScopedEVP_PKEY pkey(EVP_PKEY_new());
 338   if (!pkey)
 339     return crypto::ScopedEVP_PKEY();
 340
 341   if (!EVP_PKEY_set1_RSA(pkey.get(), rsa.get()))
 342     return crypto::ScopedEVP_PKEY();
 343
 344   return pkey.Pass();
 345 }
 346
 347 // Custom ECDSA_METHOD that uses the platform APIs.
 348 // Note that for now, only signing through ECDSA_sign() is really supported.
 349 // all other method pointers are either stubs returning errors, or no-ops.
 350
 351 const KeyExData* EcKeyGetExData(const EC_KEY* ec_key) {
 352   return reinterpret_cast<const KeyExData*>(EC_KEY_get_ex_data(
 353       ec_key, global_boringssl_engine.Get().ec_key_ex_index()));
 354 }
 355
 356 size_t EcdsaMethodGroupOrderSize(const EC_KEY* ec_key) {
 357   const KeyExData* ex_data = EcKeyGetExData(ec_key);
 358   // LogicalKeySizeInBits is the size of an EC public key. But an
 359   // ECDSA signature length depends on the size of the base point's
 360   // order. For P-256, P-384, and P-521, these two sizes are the same.
 361   return (ex_data->cssm_key->KeyHeader.LogicalKeySizeInBits + 7) / 8;
 362 }
 363
 364 int EcdsaMethodSign(const uint8_t* digest,
 365                     size_t digest_len,
 366                     uint8_t* sig,
 367                     unsigned int* sig_len,
 368                     EC_KEY* ec_key) {
 369   const KeyExData *ex_data = EcKeyGetExData(ec_key);
 370   if (!ex_data) {
 371     OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
 372     return 0;
 373   }
 374   DCHECK_EQ(CSSM_ALGID_ECDSA, ex_data->cssm_key->KeyHeader.AlgorithmId);
 375
 376   // TODO(davidben): Fix BoringSSL to make sig_len a size_t*.
 377   size_t out_len;
 378   int ret = MakeCSSMSignature(
 379       ex_data, &out_len, sig, ECDSA_size(ec_key), digest, digest_len);
 380   if (!ret)
 381     return 0;
 382   *sig_len = out_len;
 383   return 1;
 384 }
 385
 386 int EcdsaMethodVerify(const uint8_t* digest,
 387                       size_t digest_len,
 388                       const uint8_t* sig,
 389                       size_t sig_len,
 390                       EC_KEY* eckey) {
 391   NOTIMPLEMENTED();
 392   OPENSSL_PUT_ERROR(ECDSA, ECDSA_do_verify, ECDSA_R_NOT_IMPLEMENTED);
 393   return 0;
 394 }
 395
 396 const ECDSA_METHOD mac_ecdsa_method = {
 397     {
 398      0 /* references */,
 399      1 /* is_static */
 400     } /* common */,
 401     NULL /* app_data */,
 402
 403     NULL /* init */,
 404     NULL /* finish */,
 405     EcdsaMethodGroupOrderSize,
 406     EcdsaMethodSign,
 407     EcdsaMethodVerify,
 408     ECDSA_FLAG_OPAQUE,
 409 };
 410
 411 crypto::ScopedEVP_PKEY CreateECDSAWrapper(SecKeyRef key,
 412                                           const CSSM_KEY* cssm_key) {
 413   crypto::ScopedEC_KEY ec_key(
 414       EC_KEY_new_method(global_boringssl_engine.Get().engine()));
 415   if (!ec_key)
 416     return crypto::ScopedEVP_PKEY();
 417
 418   EC_KEY_set_ex_data(
 419       ec_key.get(), global_boringssl_engine.Get().ec_key_ex_index(),
 420       new KeyExData(key, cssm_key));
 421
 422   crypto::ScopedEVP_PKEY pkey(EVP_PKEY_new());
 423   if (!pkey)
 424     return crypto::ScopedEVP_PKEY();
 425
 426   if (!EVP_PKEY_set1_EC_KEY(pkey.get(), ec_key.get()))
 427     return crypto::ScopedEVP_PKEY();
 428
 429   return pkey.Pass();
 430 }
 431
 432 crypto::ScopedEVP_PKEY CreatePkeyWrapper(SecKeyRef key) {
 433   const CSSM_KEY* cssm_key;
 434   OSStatus status = SecKeyGetCSSMKey(key, &cssm_key);
 435   if (status != noErr)
 436     return crypto::ScopedEVP_PKEY();
 437
 438   switch (cssm_key->KeyHeader.AlgorithmId) {
 439     case CSSM_ALGID_RSA:
 440       return CreateRSAWrapper(key, cssm_key);
 441     case CSSM_ALGID_ECDSA:
 442       return CreateECDSAWrapper(key, cssm_key);
 443     default:
 444       // TODO(davidben): Filter out anything other than ECDSA and RSA
 445       // elsewhere. We don't support other key types.
 446       NOTREACHED();
 447       LOG(ERROR) << "Unknown key type";
 448       return crypto::ScopedEVP_PKEY();
 449   }
 450 }
 451
 452 }  // namespace
 453
 454 crypto::ScopedEVP_PKEY FetchClientCertPrivateKey(
 455     const X509Certificate* certificate) {
 456   // Look up the private key.
 457   base::ScopedCFTypeRef<SecKeyRef> private_key(
 458       FetchSecKeyRefForCertificate(certificate));
 459   if (!private_key)
 460     return crypto::ScopedEVP_PKEY();
 461
 462   // Create an EVP_PKEY wrapper.
 463   return CreatePkeyWrapper(private_key.get());
 464 }
 465
 466 }  // namespace net