crypto/symmetric_key_nss.cc

   1 // Copyright (c) 2011 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/symmetric_key.h"
   6
   7 #include <nss.h>
   8 #include <pk11pub.h>
   9
  10 #include "base/logging.h"
  11 #include "crypto/nss_util.h"
  12
  13 namespace crypto {
  14
  15 SymmetricKey::~SymmetricKey() {}
  16
  17 // static
  18 SymmetricKey* SymmetricKey::GenerateRandomKey(Algorithm algorithm,
  19                                               size_t key_size_in_bits) {
  20   DCHECK_EQ(AES, algorithm);
  21
  22   EnsureNSSInit();
  23   if (key_size_in_bits == 0)
  24     return NULL;
  25
  26   ScopedPK11Slot slot(PK11_GetBestSlot(CKM_AES_KEY_GEN, NULL));
  27   if (!slot.get())
  28     return NULL;
  29
  30   PK11SymKey* sym_key = PK11_KeyGen(slot.get(), CKM_AES_KEY_GEN, NULL,
  31                                     key_size_in_bits / 8, NULL);
  32   if (!sym_key)
  33     return NULL;
  34
  35   return new SymmetricKey(sym_key);
  36 }
  37
  38 // static
  39 SymmetricKey* SymmetricKey::DeriveKeyFromPassword(Algorithm algorithm,
  40                                                   const std::string& password,
  41                                                   const std::string& salt,
  42                                                   size_t iterations,
  43                                                   size_t key_size_in_bits) {
  44   EnsureNSSInit();
  45   if (salt.empty() || iterations == 0 || key_size_in_bits == 0)
  46     return NULL;
  47
  48   SECItem password_item;
  49   password_item.type = siBuffer;
  50   password_item.data = reinterpret_cast<unsigned char*>(
  51       const_cast<char *>(password.data()));
  52   password_item.len = password.size();
  53
  54   SECItem salt_item;
  55   salt_item.type = siBuffer;
  56   salt_item.data = reinterpret_cast<unsigned char*>(
  57       const_cast<char *>(salt.data()));
  58   salt_item.len = salt.size();
  59
  60   SECOidTag cipher_algorithm =
  61       algorithm == AES ? SEC_OID_AES_256_CBC : SEC_OID_HMAC_SHA1;
  62   ScopedSECAlgorithmID alg_id(PK11_CreatePBEV2AlgorithmID(SEC_OID_PKCS5_PBKDF2,
  63                                                           cipher_algorithm,
  64                                                           SEC_OID_HMAC_SHA1,
  65                                                           key_size_in_bits / 8,
  66                                                           iterations,
  67                                                           &salt_item));
  68   if (!alg_id.get())
  69     return NULL;
  70
  71   ScopedPK11Slot slot(PK11_GetBestSlot(SEC_OID_PKCS5_PBKDF2, NULL));
  72   if (!slot.get())
  73     return NULL;
  74
  75   PK11SymKey* sym_key = PK11_PBEKeyGen(slot.get(), alg_id.get(), &password_item,
  76                                        PR_FALSE, NULL);
  77   if (!sym_key)
  78     return NULL;
  79
  80   return new SymmetricKey(sym_key);
  81 }
  82
  83 // static
  84 SymmetricKey* SymmetricKey::Import(Algorithm algorithm,
  85                                    const std::string& raw_key) {
  86   CK_MECHANISM_TYPE cipher =
  87       algorithm == AES ? CKM_AES_CBC : CKM_SHA_1_HMAC;
  88
  89   SECItem key_item;
  90   key_item.type = siBuffer;
  91   key_item.data = reinterpret_cast<unsigned char*>(
  92       const_cast<char *>(raw_key.data()));
  93   key_item.len = raw_key.size();
  94
  95   ScopedPK11Slot slot(PK11_GetBestSlot(cipher, NULL));
  96   if (!slot.get())
  97     return NULL;
  98
  99   // The exact value of the |origin| argument doesn't matter to NSS as long as
 100   // it's not PK11_OriginFortezzaHack, so we pass PK11_OriginUnwrap as a
 101   // placeholder.
 102   PK11SymKey* sym_key = PK11_ImportSymKey(slot.get(), cipher, PK11_OriginUnwrap,
 103                                           CKA_ENCRYPT, &key_item, NULL);
 104   if (!sym_key)
 105     return NULL;
 106
 107   return new SymmetricKey(sym_key);
 108 }
 109
 110 bool SymmetricKey::GetRawKey(std::string* raw_key) {
 111   SECStatus rv = PK11_ExtractKeyValue(key_.get());
 112   if (SECSuccess != rv)
 113     return false;
 114
 115   SECItem* key_item = PK11_GetKeyData(key_.get());
 116   if (!key_item)
 117     return false;
 118
 119   raw_key->assign(reinterpret_cast<char*>(key_item->data), key_item->len);
 120   return true;
 121 }
 122
 123 SymmetricKey::SymmetricKey(PK11SymKey* key) : key_(key) {
 124   DCHECK(key);
 125 }
 126
 127 }  // namespace crypto