src/crypto/symmetric_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/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_GetInternalSlot());
  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_GetInternalSlot());
  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   EnsureNSSInit();
  87   CK_MECHANISM_TYPE cipher =
  88       algorithm == AES ? CKM_AES_CBC : CKM_SHA_1_HMAC;
  89
  90   SECItem key_item;
  91   key_item.type = siBuffer;
  92   key_item.data = reinterpret_cast<unsigned char*>(
  93       const_cast<char *>(raw_key.data()));
  94   key_item.len = raw_key.size();
  95
  96   ScopedPK11Slot slot(PK11_GetInternalSlot());
  97   if (!slot.get())
  98     return NULL;
  99
 100   // The exact value of the |origin| argument doesn't matter to NSS as long as
 101   // it's not PK11_OriginFortezzaHack, so we pass PK11_OriginUnwrap as a
 102   // placeholder.
 103   PK11SymKey* sym_key = PK11_ImportSymKey(slot.get(), cipher, PK11_OriginUnwrap,
 104                                           CKA_ENCRYPT, &key_item, NULL);
 105   if (!sym_key)
 106     return NULL;
 107
 108   return new SymmetricKey(sym_key);
 109 }
 110
 111 bool SymmetricKey::GetRawKey(std::string* raw_key) {
 112   SECStatus rv = PK11_ExtractKeyValue(key_.get());
 113   if (SECSuccess != rv)
 114     return false;
 115
 116   SECItem* key_item = PK11_GetKeyData(key_.get());
 117   if (!key_item)
 118     return false;
 119
 120   raw_key->assign(reinterpret_cast<char*>(key_item->data), key_item->len);
 121   return true;
 122 }
 123
 124 SymmetricKey::SymmetricKey(PK11SymKey* key) : key_(key) {
 125   DCHECK(key);
 126 }
 127
 128 }  // namespace crypto