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 // 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
 121   const uint8_t* data = &encrypted_private_key_info[0];
 122   const uint8_t* ptr = data;
 123   ScopedX509_SIG p8_encrypted(
 124       d2i_X509_SIG(NULL, &ptr, encrypted_private_key_info.size()));
 125   if (!p8_encrypted || ptr != data + encrypted_private_key_info.size())
 126     return NULL;
 127
 128   ScopedPKCS8_PRIV_KEY_INFO p8_decrypted;
 129   if (password.empty()) {
 130     // Hack for reading keys generated by an older version of the OpenSSL
 131     // code. OpenSSL used to use "\0\0" rather than the empty string because it
 132     // would treat the password as an ASCII string to be converted to UCS-2
 133     // while NSS used a byte string.
 134     p8_decrypted.reset(PKCS8_decrypt_pbe(
 135         p8_encrypted.get(), reinterpret_cast<const uint8_t*>("\0\0"), 2));
 136   }
 137   if (!p8_decrypted) {
 138     p8_decrypted.reset(PKCS8_decrypt_pbe(
 139         p8_encrypted.get(),
 140         reinterpret_cast<const uint8_t*>(password.data()),
 141         password.size()));
 142   }
 143
 144   if (!p8_decrypted)
 145     return NULL;
 146
 147   // Create a new EVP_PKEY for it.
 148   scoped_ptr<ECPrivateKey> result(new ECPrivateKey);
 149   result->key_ = EVP_PKCS82PKEY(p8_decrypted.get());
 150   if (!result->key_ || EVP_PKEY_type(result->key_->type) != EVP_PKEY_EC)
 151     return NULL;
 152
 153   return result.release();
 154 }
 155
 156 bool ECPrivateKey::ExportEncryptedPrivateKey(
 157     const std::string& password,
 158     int iterations,
 159     std::vector<uint8>* output) {
 160   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 161   // Convert into a PKCS#8 object.
 162   ScopedPKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(key_));
 163   if (!pkcs8.get())
 164     return false;
 165
 166   // Encrypt the object.
 167   // NOTE: NSS uses SEC_OID_PKCS12_V2_PBE_WITH_SHA1_AND_3KEY_TRIPLE_DES_CBC
 168   // so use NID_pbe_WithSHA1And3_Key_TripleDES_CBC which should be the OpenSSL
 169   // equivalent.
 170   ScopedX509_SIG encrypted(PKCS8_encrypt_pbe(
 171       NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
 172       reinterpret_cast<const uint8_t*>(password.data()),
 173       password.size(),
 174       NULL,
 175       0,
 176       iterations,
 177       pkcs8.get()));
 178   if (!encrypted.get())
 179     return false;
 180
 181   // Write it into |*output|
 182   return ExportKeyWithBio(encrypted.get(),
 183                           reinterpret_cast<ExportBioFunction>(i2d_PKCS8_bio),
 184                           output);
 185 }
 186
 187 bool ECPrivateKey::ExportPublicKey(std::vector<uint8>* output) {
 188   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 189   return ExportKeyWithBio(
 190       key_, reinterpret_cast<ExportBioFunction>(i2d_PUBKEY_bio), output);
 191 }
 192
 193 bool ECPrivateKey::ExportRawPublicKey(std::string* output) {
 194   // i2d_PublicKey will produce an ANSI X9.62 public key which, for a P-256
 195   // key, is 0x04 (meaning uncompressed) followed by the x and y field
 196   // elements as 32-byte, big-endian numbers.
 197   static const int kExpectedKeyLength = 65;
 198
 199   int len = i2d_PublicKey(key_, NULL);
 200   if (len != kExpectedKeyLength)
 201     return false;
 202
 203   uint8 buf[kExpectedKeyLength];
 204   uint8* derp = buf;
 205   len = i2d_PublicKey(key_, &derp);
 206   if (len != kExpectedKeyLength)
 207     return false;
 208
 209   output->assign(reinterpret_cast<char*>(buf + 1), kExpectedKeyLength - 1);
 210   return true;
 211 }
 212
 213 bool ECPrivateKey::ExportValue(std::vector<uint8>* output) {
 214   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 215   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 216   return ExportKey(ec_key.get(),
 217                    reinterpret_cast<ExportDataFunction>(i2d_ECPrivateKey),
 218                    output);
 219 }
 220
 221 bool ECPrivateKey::ExportECParams(std::vector<uint8>* output) {
 222   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 223   ScopedEC_KEY ec_key(EVP_PKEY_get1_EC_KEY(key_));
 224   return ExportKey(ec_key.get(),
 225                    reinterpret_cast<ExportDataFunction>(i2d_ECParameters),
 226                    output);
 227 }
 228
 229 ECPrivateKey::ECPrivateKey() : key_(NULL) {}
 230
 231 }  // namespace crypto