crypto/ec_private_key_openssl.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 #include <openssl/ec.h>
   8 #include <openssl/evp.h>
   9 #include <openssl/pkcs12.h>
  10 #include <openssl/x509.h>
  11
  12 #include "base/logging.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "crypto/openssl_util.h"
  15 #include "crypto/scoped_openssl_types.h"
  16
  17 namespace crypto {
  18
  19 namespace {
  20
  21 // Function pointer definition, for injecting the required key export function
  22 // into ExportKeyWithBio, below. |bio| is a temporary memory BIO object, and
  23 // |key| is a handle to the input key object. Return 1 on success, 0 otherwise.
  24 // NOTE: Used with OpenSSL functions, which do not comply with the Chromium
  25 //       style guide, hence the unusual parameter placement / types.
  26 typedef int (*ExportBioFunction)(BIO* bio, const void* key);
  27
  28 using ScopedPKCS8_PRIV_KEY_INFO =
  29     ScopedOpenSSL<PKCS8_PRIV_KEY_INFO, PKCS8_PRIV_KEY_INFO_free>;
  30 using ScopedX509_SIG = ScopedOpenSSL<X509_SIG, X509_SIG_free>;
  31
  32 // Helper to export |key| into |output| via the specified ExportBioFunction.
  33 bool ExportKeyWithBio(const void* key,
  34                       ExportBioFunction export_fn,
  35                       std::vector<uint8>* output) {
  36   if (!key)
  37     return false;
  38
  39   ScopedBIO bio(BIO_new(BIO_s_mem()));
  40   if (!bio.get())
  41     return false;
  42
  43   if (!export_fn(bio.get(), key))
  44     return false;
  45
  46   char* data = NULL;
  47   long len = BIO_get_mem_data(bio.get(), &data);
  48   if (!data || len < 0)
  49     return false;
  50
  51   output->assign(data, data + len);
  52   return true;
  53 }
  54
  55 // Function pointer definition, for injecting the required key export function
  56 // into ExportKey below. |key| is a pointer to the input key object,
  57 // and |data| is either NULL, or the address of an 'unsigned char*' pointer
  58 // that points to the start of the output buffer. The function must return
  59 // the number of bytes required to export the data, or -1 in case of error.
  60 typedef int (*ExportDataFunction)(const void* key, unsigned char** data);
  61
  62 // Helper to export |key| into |output| via the specified export function.
  63 bool ExportKey(const void* key,
  64                ExportDataFunction export_fn,
  65                std::vector<uint8>* output) {
  66   if (!key)
  67     return false;
  68
  69   int data_len = export_fn(key, NULL);
  70   if (data_len < 0)
  71     return false;
  72
  73   output->resize(static_cast<size_t>(data_len));
  74   unsigned char* data = &(*output)[0];
  75   if (export_fn(key, &data) < 0)
  76     return false;
  77
  78   return true;
  79 }
  80
  81 }  // namespace
  82
  83 ECPrivateKey::~ECPrivateKey() {
  84   if (key_)
  85     EVP_PKEY_free(key_);
  86 }
  87
  88 ECPrivateKey* ECPrivateKey::Copy() const {
  89   scoped_ptr<ECPrivateKey> copy(new ECPrivateKey);
  90   if (key_)
  91     copy->key_ = EVP_PKEY_up_ref(key_);
  92   return copy.release();
  93 }
  94
  95 // static
  96 bool ECPrivateKey::IsSupported() { return true; }
  97
  98 // static
  99 ECPrivateKey* ECPrivateKey::Create() {
 100   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 101
 102   ScopedEC_KEY ec_key(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
 103   if (!ec_key.get() || !EC_KEY_generate_key(ec_key.get()))
 104     return NULL;
 105
 106   scoped_ptr<ECPrivateKey> result(new ECPrivateKey());
 107   result->key_ = EVP_PKEY_new();
 108   if (!result->key_ || !EVP_PKEY_set1_EC_KEY(result->key_, ec_key.get()))
 109     return NULL;
 110
 111   CHECK_EQ(EVP_PKEY_EC, EVP_PKEY_type(result->key_->type));
 112   return result.release();
 113 }
 114
 115 // static
 116 ECPrivateKey* ECPrivateKey::CreateFromEncryptedPrivateKeyInfo(
 117     const std::string& password,
 118     const std::vector<uint8>& encrypted_private_key_info,
 119     const std::vector<uint8>& subject_public_key_info) {
 120   // NOTE: The |subject_public_key_info| can be ignored here, it is only
 121   // useful for the NSS implementation (which uses the public key's SHA1
 122   // as a lookup key when storing the private one in its store).
 123   if (encrypted_private_key_info.empty())
 124     return NULL;
 125
 126   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 127
 128   const uint8_t* data = &encrypted_private_key_info[0];
 129   const uint8_t* ptr = data;
 130   ScopedX509_SIG p8_encrypted(
 131       d2i_X509_SIG(NULL, &ptr, encrypted_private_key_info.size()));
 132   if (!p8_encrypted || ptr != data + encrypted_private_key_info.size())
 133     return NULL;
 134
 135   ScopedPKCS8_PRIV_KEY_INFO p8_decrypted;
 136   if (password.empty()) {
 137     // Hack for reading keys generated by an older version of the OpenSSL
 138     // code. OpenSSL used to use "\0\0" rather than the empty string because it
 139     // would treat the password as an ASCII string to be converted to UCS-2
 140     // while NSS used a byte string.
 141     p8_decrypted.reset(PKCS8_decrypt_pbe(
 142         p8_encrypted.get(), reinterpret_cast<const uint8_t*>("\0\0"), 2));
 143   }
 144   if (!p8_decrypted) {
 145     p8_decrypted.reset(PKCS8_decrypt_pbe(
 146         p8_encrypted.get(),
 147         reinterpret_cast<const uint8_t*>(password.data()),
 148         password.size()));
 149   }
 150
 151   if (!p8_decrypted)
 152     return NULL;
 153
 154   // Create a new EVP_PKEY for it.
 155   scoped_ptr<ECPrivateKey> result(new ECPrivateKey);
 156   result->key_ = EVP_PKCS82PKEY(p8_decrypted.get());
 157   if (!result->key_ || EVP_PKEY_type(result->key_->type) != EVP_PKEY_EC)
 158     return NULL;
 159
 160   return result.release();
 161 }
 162
 163 bool ECPrivateKey::ExportEncryptedPrivateKey(
 164     const std::string& password,
 165     int iterations,
 166     std::vector<uint8>* output) {
 167   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 168   // Convert into a PKCS#8 object.
 169   ScopedPKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(key_));
 170   if (!pkcs8.get())
 171     return false;
 172
 173   // Encrypt the object.
 174   // NOTE: NSS uses SEC_OID_PKCS12_V2_PBE_WITH_SHA1_AND_3KEY_TRIPLE_DES_CBC
 175   // so use NID_pbe_WithSHA1And3_Key_TripleDES_CBC which should be the OpenSSL
 176   // equivalent.
 177   ScopedX509_SIG encrypted(PKCS8_encrypt_pbe(
 178       NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
 179       reinterpret_cast<const uint8_t*>(password.data()),
 180       password.size(),
 181       NULL,
 182       0,
 183       iterations,
 184       pkcs8.get()));
 185   if (!encrypted.get())
 186     return false;
 187
 188   // Write it into |*output|
 189   return ExportKeyWithBio(encrypted.get(),
 190                           reinterpret_cast<ExportBioFunction>(i2d_PKCS8_bio),
 191                           output);
 192 }
 193
 194 bool ECPrivateKey::ExportPublicKey(std::vector<uint8>* output) {
 195   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 196   return ExportKeyWithBio(
 197       key_, reinterpret_cast<ExportBioFunction>(i2d_PUBKEY_bio), output);
 198 }
 199
 200 bool ECPrivateKey::ExportRawPublicKey(std::string* output) {
 201   // i2d_PublicKey will produce an ANSI X9.62 public key which, for a P-256
 202   // key, is 0x04 (meaning uncompressed) followed by the x and y field
 203   // elements as 32-byte, big-endian numbers.
 204   static const int kExpectedKeyLength = 65;
 205
 206   int len = i2d_PublicKey(key_, NULL);
 207   if (len != kExpectedKeyLength)
 208     return false;
 209
 210   uint8 buf[kExpectedKeyLength];
 211   uint8* derp = buf;
 212   len = i2d_PublicKey(key_, &derp);
 213   if (len != kExpectedKeyLength)
 214     return false;
 215
 216   output->assign(reinterpret_cast<char*>(buf + 1), kExpectedKeyLength - 1);
 217   return true;
 218 }
 219
 220 bool ECPrivateKey::ExportValue(std::vector<uint8>* output) {
 221   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 222   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 223   return ExportKey(ec_key.get(),
 224                    reinterpret_cast<ExportDataFunction>(i2d_ECPrivateKey),
 225                    output);
 226 }
 227
 228 bool ECPrivateKey::ExportECParams(std::vector<uint8>* output) {
 229   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 230   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 231   return ExportKey(ec_key.get(),
 232                    reinterpret_cast<ExportDataFunction>(i2d_ECParameters),
 233                    output);
 234 }
 235
 236 ECPrivateKey::ECPrivateKey() : key_(NULL) {}
 237
 238 }  // namespace crypto