crypto/ec_private_key_nss.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 "crypto/ec_private_key.h"
   6
   7 extern "C" {
   8 // Work around NSS missing SEC_BEGIN_PROTOS in secmodt.h.  This must come before
   9 // other NSS headers.
  10 #include <secmodt.h>
  11 }
  12
  13 #include <cryptohi.h>
  14 #include <keyhi.h>
  15 #include <pk11pub.h>
  16 #include <secmod.h>
  17
  18 #include "base/lazy_instance.h"
  19 #include "base/logging.h"
  20 #include "base/memory/scoped_ptr.h"
  21 #include "crypto/nss_util.h"
  22 #include "crypto/nss_util_internal.h"
  23 #include "crypto/scoped_nss_types.h"
  24 #include "crypto/third_party/nss/chromium-nss.h"
  25
  26 namespace {
  27
  28 PK11SlotInfo* GetTempKeySlot() {
  29   return PK11_GetInternalSlot();
  30 }
  31
  32 class EllipticCurveSupportChecker {
  33  public:
  34   EllipticCurveSupportChecker() {
  35     // NOTE: we can do this check here only because we use the NSS internal
  36     // slot.  If we support other slots in the future, checking whether they
  37     // support ECDSA may block NSS, and the value may also change as devices are
  38     // inserted/removed, so we would need to re-check on every use.
  39     crypto::EnsureNSSInit();
  40     crypto::ScopedPK11Slot slot(GetTempKeySlot());
  41     supported_ = PK11_DoesMechanism(slot.get(), CKM_EC_KEY_PAIR_GEN) &&
  42         PK11_DoesMechanism(slot.get(), CKM_ECDSA);
  43   }
  44
  45   bool Supported() {
  46     return supported_;
  47   }
  48
  49  private:
  50   bool supported_;
  51 };
  52
  53 static base::LazyInstance<EllipticCurveSupportChecker>::Leaky
  54     g_elliptic_curve_supported = LAZY_INSTANCE_INITIALIZER;
  55
  56 // Copied from rsa_private_key_nss.cc.
  57 static bool ReadAttribute(SECKEYPrivateKey* key,
  58                           CK_ATTRIBUTE_TYPE type,
  59                           std::vector<uint8>* output) {
  60   SECItem item;
  61   SECStatus rv;
  62   rv = PK11_ReadRawAttribute(PK11_TypePrivKey, key, type, &item);
  63   if (rv != SECSuccess) {
  64     DLOG(ERROR) << "PK11_ReadRawAttribute: " << PORT_GetError();
  65     return false;
  66   }
  67
  68   output->assign(item.data, item.data + item.len);
  69   SECITEM_FreeItem(&item, PR_FALSE);
  70   return true;
  71 }
  72
  73 }  // namespace
  74
  75 namespace crypto {
  76
  77 ECPrivateKey::~ECPrivateKey() {
  78   if (key_)
  79     SECKEY_DestroyPrivateKey(key_);
  80   if (public_key_)
  81     SECKEY_DestroyPublicKey(public_key_);
  82 }
  83
  84 // static
  85 bool ECPrivateKey::IsSupported() {
  86   return g_elliptic_curve_supported.Get().Supported();
  87 }
  88
  89 // static
  90 ECPrivateKey* ECPrivateKey::Create() {
  91   EnsureNSSInit();
  92
  93   ScopedPK11Slot slot(GetTempKeySlot());
  94   return CreateWithParams(slot.get(),
  95                           false /* not permanent */,
  96                           false /* not sensitive */);
  97 }
  98
  99 #if defined(USE_NSS)
 100 // static
 101 ECPrivateKey* ECPrivateKey::CreateSensitive(PK11SlotInfo* slot) {
 102   return CreateWithParams(
 103       slot, true /* permanent */, true /* sensitive */);
 104 }
 105 #endif
 106
 107 // static
 108 ECPrivateKey* ECPrivateKey::CreateFromEncryptedPrivateKeyInfo(
 109     const std::string& password,
 110     const std::vector<uint8>& encrypted_private_key_info,
 111     const std::vector<uint8>& subject_public_key_info) {
 112   EnsureNSSInit();
 113
 114   ScopedPK11Slot slot(GetTempKeySlot());
 115   return CreateFromEncryptedPrivateKeyInfoWithParams(
 116       slot.get(),
 117       password,
 118       encrypted_private_key_info,
 119       subject_public_key_info,
 120       false /* not permanent */,
 121       false /* not sensitive */);
 122 }
 123
 124 #if defined(USE_NSS)
 125 // static
 126 ECPrivateKey* ECPrivateKey::CreateSensitiveFromEncryptedPrivateKeyInfo(
 127     PK11SlotInfo* slot,
 128     const std::string& password,
 129     const std::vector<uint8>& encrypted_private_key_info,
 130     const std::vector<uint8>& subject_public_key_info) {
 131   return CreateFromEncryptedPrivateKeyInfoWithParams(
 132       slot,
 133       password,
 134       encrypted_private_key_info,
 135       subject_public_key_info,
 136       true /* permanent */,
 137       true /* sensitive */);
 138 }
 139 #endif
 140
 141 // static
 142 bool ECPrivateKey::ImportFromEncryptedPrivateKeyInfo(
 143     PK11SlotInfo* slot,
 144     const std::string& password,
 145     const uint8* encrypted_private_key_info,
 146     size_t encrypted_private_key_info_len,
 147     CERTSubjectPublicKeyInfo* decoded_spki,
 148     bool permanent,
 149     bool sensitive,
 150     SECKEYPrivateKey** key,
 151     SECKEYPublicKey** public_key) {
 152   if (!slot)
 153     return false;
 154
 155   *public_key = SECKEY_ExtractPublicKey(decoded_spki);
 156
 157   if (!*public_key) {
 158     DLOG(ERROR) << "SECKEY_ExtractPublicKey: " << PORT_GetError();
 159     return false;
 160   }
 161
 162   if (SECKEY_GetPublicKeyType(*public_key) != ecKey) {
 163     DLOG(ERROR) << "The public key is not an EC key";
 164     SECKEY_DestroyPublicKey(*public_key);
 165     *public_key = NULL;
 166     return false;
 167   }
 168
 169   SECItem encoded_epki = {
 170     siBuffer,
 171     const_cast<unsigned char*>(encrypted_private_key_info),
 172     static_cast<unsigned>(encrypted_private_key_info_len)
 173   };
 174   SECKEYEncryptedPrivateKeyInfo epki;
 175   memset(&epki, 0, sizeof(epki));
 176
 177   ScopedPLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
 178
 179   SECStatus rv = SEC_QuickDERDecodeItem(
 180       arena.get(),
 181       &epki,
 182       SEC_ASN1_GET(SECKEY_EncryptedPrivateKeyInfoTemplate),
 183       &encoded_epki);
 184   if (rv != SECSuccess) {
 185     DLOG(ERROR) << "SEC_QuickDERDecodeItem: " << PORT_GetError();
 186     SECKEY_DestroyPublicKey(*public_key);
 187     *public_key = NULL;
 188     return false;
 189   }
 190
 191   SECItem password_item = {
 192     siBuffer,
 193     reinterpret_cast<unsigned char*>(const_cast<char*>(password.data())),
 194     static_cast<unsigned>(password.size())
 195   };
 196
 197   rv = ImportEncryptedECPrivateKeyInfoAndReturnKey(
 198       slot,
 199       &epki,
 200       &password_item,
 201       NULL,  // nickname
 202       &(*public_key)->u.ec.publicValue,
 203       permanent,
 204       sensitive,
 205       key,
 206       NULL);  // wincx
 207   if (rv != SECSuccess) {
 208     DLOG(ERROR) << "ImportEncryptedECPrivateKeyInfoAndReturnKey: "
 209                 << PORT_GetError();
 210     SECKEY_DestroyPublicKey(*public_key);
 211     *public_key = NULL;
 212     return false;
 213   }
 214
 215   return true;
 216 }
 217
 218 ECPrivateKey* ECPrivateKey::Copy() const {
 219   scoped_ptr<ECPrivateKey> copy(new ECPrivateKey);
 220   if (key_) {
 221     copy->key_ = SECKEY_CopyPrivateKey(key_);
 222     if (!copy->key_)
 223       return NULL;
 224   }
 225   if (public_key_) {
 226     copy->public_key_ = SECKEY_CopyPublicKey(public_key_);
 227     if (!copy->public_key_)
 228       return NULL;
 229   }
 230   return copy.release();
 231 }
 232
 233 bool ECPrivateKey::ExportEncryptedPrivateKey(
 234     const std::string& password,
 235     int iterations,
 236     std::vector<uint8>* output) {
 237   // We export as an EncryptedPrivateKeyInfo bundle instead of a plain PKCS #8
 238   // PrivateKeyInfo because PK11_ImportDERPrivateKeyInfoAndReturnKey doesn't
 239   // support EC keys.
 240   // https://bugzilla.mozilla.org/show_bug.cgi?id=327773
 241   SECItem password_item = {
 242     siBuffer,
 243     reinterpret_cast<unsigned char*>(const_cast<char*>(password.data())),
 244     static_cast<unsigned>(password.size())
 245   };
 246
 247   SECKEYEncryptedPrivateKeyInfo* encrypted = PK11_ExportEncryptedPrivKeyInfo(
 248       NULL,  // Slot, optional.
 249       SEC_OID_PKCS12_V2_PBE_WITH_SHA1_AND_3KEY_TRIPLE_DES_CBC,
 250       &password_item,
 251       key_,
 252       iterations,
 253       NULL);  // wincx.
 254
 255   if (!encrypted) {
 256     DLOG(ERROR) << "PK11_ExportEncryptedPrivKeyInfo: " << PORT_GetError();
 257     return false;
 258   }
 259
 260   ScopedPLArenaPool arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
 261   SECItem der_key = {siBuffer, NULL, 0};
 262   SECItem* encoded_item = SEC_ASN1EncodeItem(
 263       arena.get(),
 264       &der_key,
 265       encrypted,
 266       SEC_ASN1_GET(SECKEY_EncryptedPrivateKeyInfoTemplate));
 267   SECKEY_DestroyEncryptedPrivateKeyInfo(encrypted, PR_TRUE);
 268   if (!encoded_item) {
 269     DLOG(ERROR) << "SEC_ASN1EncodeItem: " << PORT_GetError();
 270     return false;
 271   }
 272
 273   output->assign(der_key.data, der_key.data + der_key.len);
 274
 275   return true;
 276 }
 277
 278 bool ECPrivateKey::ExportPublicKey(std::vector<uint8>* output) {
 279   ScopedSECItem der_pubkey(
 280       SECKEY_EncodeDERSubjectPublicKeyInfo(public_key_));
 281   if (!der_pubkey.get()) {
 282     return false;
 283   }
 284
 285   output->assign(der_pubkey->data, der_pubkey->data + der_pubkey->len);
 286   return true;
 287 }
 288
 289 bool ECPrivateKey::ExportRawPublicKey(std::string* output) {
 290   // public_key_->u.ec.publicValue is an ANSI X9.62 public key which, for
 291   // a P-256 key, is 0x04 (meaning uncompressed) followed by the x and y field
 292   // elements as 32-byte, big-endian numbers.
 293   static const unsigned int kExpectedKeyLength = 65;
 294
 295   CHECK_EQ(ecKey, SECKEY_GetPublicKeyType(public_key_));
 296   const unsigned char* const data = public_key_->u.ec.publicValue.data;
 297   const unsigned int len = public_key_->u.ec.publicValue.len;
 298   if (len != kExpectedKeyLength || data[0] != 0x04)
 299     return false;
 300
 301   output->assign(reinterpret_cast<const char*>(data + 1),
 302                  kExpectedKeyLength - 1);
 303   return true;
 304 }
 305
 306 bool ECPrivateKey::ExportValue(std::vector<uint8>* output) {
 307   return ReadAttribute(key_, CKA_VALUE, output);
 308 }
 309
 310 bool ECPrivateKey::ExportECParams(std::vector<uint8>* output) {
 311   return ReadAttribute(key_, CKA_EC_PARAMS, output);
 312 }
 313
 314 ECPrivateKey::ECPrivateKey() : key_(NULL), public_key_(NULL) {}
 315
 316 // static
 317 ECPrivateKey* ECPrivateKey::CreateWithParams(PK11SlotInfo* slot,
 318                                              bool permanent,
 319                                              bool sensitive) {
 320   if (!slot)
 321     return NULL;
 322
 323   scoped_ptr<ECPrivateKey> result(new ECPrivateKey);
 324
 325   SECOidData* oid_data = SECOID_FindOIDByTag(SEC_OID_SECG_EC_SECP256R1);
 326   if (!oid_data) {
 327     DLOG(ERROR) << "SECOID_FindOIDByTag: " << PORT_GetError();
 328     return NULL;
 329   }
 330
 331   // SECKEYECParams is a SECItem containing the DER encoded ASN.1 ECParameters
 332   // value.  For a named curve, that is just the OBJECT IDENTIFIER of the curve.
 333   // In addition to the oid data, the encoding requires one byte for the ASN.1
 334   // tag and one byte for the length (assuming the length is <= 127).
 335   DCHECK_LE(oid_data->oid.len, 127U);
 336   std::vector<unsigned char> parameters_buf(2 + oid_data->oid.len);
 337   SECKEYECParams ec_parameters = {
 338     siDEROID, &parameters_buf[0],
 339     static_cast<unsigned>(parameters_buf.size())
 340   };
 341
 342   ec_parameters.data[0] = SEC_ASN1_OBJECT_ID;
 343   ec_parameters.data[1] = oid_data->oid.len;
 344   memcpy(ec_parameters.data + 2, oid_data->oid.data, oid_data->oid.len);
 345
 346   result->key_ = PK11_GenerateKeyPair(slot,
 347                                       CKM_EC_KEY_PAIR_GEN,
 348                                       &ec_parameters,
 349                                       &result->public_key_,
 350                                       permanent,
 351                                       sensitive,
 352                                       NULL);
 353   if (!result->key_) {
 354     DLOG(ERROR) << "PK11_GenerateKeyPair: " << PORT_GetError();
 355     return NULL;
 356   }
 357   CHECK_EQ(ecKey, SECKEY_GetPublicKeyType(result->public_key_));
 358
 359   return result.release();
 360 }
 361
 362 // static
 363 ECPrivateKey* ECPrivateKey::CreateFromEncryptedPrivateKeyInfoWithParams(
 364     PK11SlotInfo* slot,
 365     const std::string& password,
 366     const std::vector<uint8>& encrypted_private_key_info,
 367     const std::vector<uint8>& subject_public_key_info,
 368     bool permanent,
 369     bool sensitive) {
 370   scoped_ptr<ECPrivateKey> result(new ECPrivateKey);
 371
 372   SECItem encoded_spki = {
 373     siBuffer,
 374     const_cast<unsigned char*>(&subject_public_key_info[0]),
 375     static_cast<unsigned>(subject_public_key_info.size())
 376   };
 377   CERTSubjectPublicKeyInfo* decoded_spki = SECKEY_DecodeDERSubjectPublicKeyInfo(
 378       &encoded_spki);
 379   if (!decoded_spki) {
 380     DLOG(ERROR) << "SECKEY_DecodeDERSubjectPublicKeyInfo: " << PORT_GetError();
 381     return NULL;
 382   }
 383
 384   bool success = ImportFromEncryptedPrivateKeyInfo(
 385       slot,
 386       password,
 387       &encrypted_private_key_info[0],
 388       encrypted_private_key_info.size(),
 389       decoded_spki,
 390       permanent,
 391       sensitive,
 392       &result->key_,
 393       &result->public_key_);
 394
 395   SECKEY_DestroySubjectPublicKeyInfo(decoded_spki);
 396
 397   if (success) {
 398     CHECK_EQ(ecKey, SECKEY_GetPublicKeyType(result->public_key_));
 399     return result.release();
 400   }
 401
 402   return NULL;
 403 }
 404
 405 }  // namespace crypto