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
~SymmetricKey()15 SymmetricKey::~SymmetricKey() {}
16
17 // static
GenerateRandomKey(Algorithm algorithm,size_t key_size_in_bits)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
DeriveKeyFromPassword(Algorithm algorithm,const std::string & password,const std::string & salt,size_t iterations,size_t key_size_in_bits)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
Import(Algorithm algorithm,const std::string & raw_key)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
GetRawKey(std::string * raw_key)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
SymmetricKey(PK11SymKey * key)123 SymmetricKey::SymmetricKey(PK11SymKey* key) : key_(key) {
124 DCHECK(key);
125 }
126
127 } // namespace crypto
128