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 typedef ScopedOpenSSL<PKCS8_PRIV_KEY_INFO, PKCS8_PRIV_KEY_INFO_free>::Type
  29     ScopedPKCS8_PRIV_KEY_INFO;
  30 typedef ScopedOpenSSL<X509_SIG, X509_SIG_free>::Type ScopedX509_SIG;
  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 // static
  89 bool ECPrivateKey::IsSupported() { return true; }
  90
  91 // static
  92 ECPrivateKey* ECPrivateKey::Create() {
  93   OpenSSLErrStackTracer err_tracer(FROM_HERE);
  94
  95   ScopedEC_KEY ec_key(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1));
  96   if (!ec_key.get() || !EC_KEY_generate_key(ec_key.get()))
  97     return NULL;
  98
  99   scoped_ptr<ECPrivateKey> result(new ECPrivateKey());
 100   result->key_ = EVP_PKEY_new();
 101   if (!result->key_ || !EVP_PKEY_set1_EC_KEY(result->key_, ec_key.get()))
 102     return NULL;
 103
 104   CHECK_EQ(EVP_PKEY_EC, EVP_PKEY_type(result->key_->type));
 105   return result.release();
 106 }
 107
 108 // static
 109 ECPrivateKey* ECPrivateKey::CreateFromEncryptedPrivateKeyInfo(
 110     const std::string& password,
 111     const std::vector<uint8>& encrypted_private_key_info,
 112     const std::vector<uint8>& subject_public_key_info) {
 113   // NOTE: The |subject_public_key_info| can be ignored here, it is only
 114   // useful for the NSS implementation (which uses the public key's SHA1
 115   // as a lookup key when storing the private one in its store).
 116   if (encrypted_private_key_info.empty())
 117     return NULL;
 118
 119   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 120   // Write the encrypted private key into a memory BIO.
 121   char* private_key_data = reinterpret_cast<char*>(
 122       const_cast<uint8*>(&encrypted_private_key_info[0]));
 123   int private_key_data_len =
 124       static_cast<int>(encrypted_private_key_info.size());
 125   ScopedBIO bio(BIO_new_mem_buf(private_key_data, private_key_data_len));
 126   if (!bio.get())
 127     return NULL;
 128
 129   // Convert it, then decrypt it into a PKCS#8 object.
 130   ScopedX509_SIG p8_encrypted(d2i_PKCS8_bio(bio.get(), NULL));
 131   if (!p8_encrypted.get())
 132     return NULL;
 133
 134   ScopedPKCS8_PRIV_KEY_INFO p8_decrypted(PKCS8_decrypt(
 135       p8_encrypted.get(), password.c_str(), static_cast<int>(password.size())));
 136   if (!p8_decrypted.get() && password.empty()) {
 137     // Hack for reading keys generated by ec_private_key_nss. Passing NULL
 138     // causes OpenSSL to use an empty password instead of "\0\0".
 139     p8_decrypted.reset(PKCS8_decrypt(p8_encrypted.get(), NULL, 0));
 140   }
 141   if (!p8_decrypted.get())
 142     return NULL;
 143
 144   // Create a new EVP_PKEY for it.
 145   scoped_ptr<ECPrivateKey> result(new ECPrivateKey);
 146   result->key_ = EVP_PKCS82PKEY(p8_decrypted.get());
 147   if (!result->key_ || EVP_PKEY_type(result->key_->type) != EVP_PKEY_EC)
 148     return NULL;
 149
 150   return result.release();
 151 }
 152
 153 bool ECPrivateKey::ExportEncryptedPrivateKey(
 154     const std::string& password,
 155     int iterations,
 156     std::vector<uint8>* output) {
 157   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 158   // Convert into a PKCS#8 object.
 159   ScopedPKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(key_));
 160   if (!pkcs8.get())
 161     return false;
 162
 163   // Encrypt the object.
 164   // NOTE: NSS uses SEC_OID_PKCS12_V2_PBE_WITH_SHA1_AND_3KEY_TRIPLE_DES_CBC
 165   // so use NID_pbe_WithSHA1And3_Key_TripleDES_CBC which should be the OpenSSL
 166   // equivalent.
 167   ScopedX509_SIG encrypted(PKCS8_encrypt(NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
 168                                          NULL,
 169                                          password.c_str(),
 170                                          static_cast<int>(password.size()),
 171                                          NULL,
 172                                          0,
 173                                          iterations,
 174                                          pkcs8.get()));
 175   if (!encrypted.get())
 176     return false;
 177
 178   // Write it into |*output|
 179   return ExportKeyWithBio(encrypted.get(),
 180                           reinterpret_cast<ExportBioFunction>(i2d_PKCS8_bio),
 181                           output);
 182 }
 183
 184 bool ECPrivateKey::ExportPublicKey(std::vector<uint8>* output) {
 185   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 186   return ExportKeyWithBio(
 187       key_, reinterpret_cast<ExportBioFunction>(i2d_PUBKEY_bio), output);
 188 }
 189
 190 bool ECPrivateKey::ExportRawPublicKey(std::string* output) {
 191   // i2d_PublicKey will produce an ANSI X9.62 public key which, for a P-256
 192   // key, is 0x04 (meaning uncompressed) followed by the x and y field
 193   // elements as 32-byte, big-endian numbers.
 194   static const int kExpectedKeyLength = 65;
 195
 196   int len = i2d_PublicKey(key_, NULL);
 197   if (len != kExpectedKeyLength)
 198     return false;
 199
 200   uint8 buf[kExpectedKeyLength];
 201   uint8* derp = buf;
 202   len = i2d_PublicKey(key_, &derp);
 203   if (len != kExpectedKeyLength)
 204     return false;
 205
 206   output->assign(reinterpret_cast<char*>(buf + 1), kExpectedKeyLength - 1);
 207   return true;
 208 }
 209
 210 bool ECPrivateKey::ExportValue(std::vector<uint8>* output) {
 211   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 212   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 213   return ExportKey(ec_key.get(),
 214                    reinterpret_cast<ExportDataFunction>(i2d_ECPrivateKey),
 215                    output);
 216 }
 217
 218 bool ECPrivateKey::ExportECParams(std::vector<uint8>* output) {
 219   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 220   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 221   return ExportKey(ec_key.get(),
 222                    reinterpret_cast<ExportDataFunction>(i2d_ECParameters),
 223                    output);
 224 }
 225
 226 ECPrivateKey::ECPrivateKey() : key_(NULL) {}
 227
 228 }  // namespace crypto