1 /*
2 * Copyright 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "openssl_utils.h"
18
19 #include <keymaster/android_keymaster_utils.h>
20
21 #include "openssl_err.h"
22
23 namespace keymaster {
24
ec_get_group_size(const EC_GROUP * group,size_t * key_size_bits)25 keymaster_error_t ec_get_group_size(const EC_GROUP* group, size_t* key_size_bits) {
26 switch (EC_GROUP_get_curve_name(group)) {
27 case NID_secp224r1:
28 *key_size_bits = 224;
29 break;
30 case NID_X9_62_prime256v1:
31 *key_size_bits = 256;
32 break;
33 case NID_secp384r1:
34 *key_size_bits = 384;
35 break;
36 case NID_secp521r1:
37 *key_size_bits = 521;
38 break;
39 default:
40 return KM_ERROR_UNSUPPORTED_EC_FIELD;
41 }
42 return KM_ERROR_OK;
43 }
44
ec_get_group(keymaster_ec_curve_t curve)45 EC_GROUP* ec_get_group(keymaster_ec_curve_t curve) {
46 switch (curve) {
47 case KM_EC_CURVE_P_224:
48 return EC_GROUP_new_by_curve_name(NID_secp224r1);
49 break;
50 case KM_EC_CURVE_P_256:
51 return EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
52 break;
53 case KM_EC_CURVE_P_384:
54 return EC_GROUP_new_by_curve_name(NID_secp384r1);
55 break;
56 case KM_EC_CURVE_P_521:
57 return EC_GROUP_new_by_curve_name(NID_secp521r1);
58 break;
59 default:
60 return nullptr;
61 break;
62 }
63 }
64
convert_bn_to_blob(BIGNUM * bn,keymaster_blob_t * blob)65 void convert_bn_to_blob(BIGNUM* bn, keymaster_blob_t* blob) {
66 blob->data_length = BN_num_bytes(bn);
67 blob->data = new uint8_t[blob->data_length];
68 BN_bn2bin(bn, const_cast<uint8_t*>(blob->data));
69 }
70
convert_to_evp(keymaster_algorithm_t algorithm)71 static int convert_to_evp(keymaster_algorithm_t algorithm) {
72 switch (algorithm) {
73 case KM_ALGORITHM_RSA:
74 return EVP_PKEY_RSA;
75 case KM_ALGORITHM_EC:
76 return EVP_PKEY_EC;
77 default:
78 return -1;
79 };
80 }
81
convert_pkcs8_blob_to_evp(const uint8_t * key_data,size_t key_length,keymaster_algorithm_t expected_algorithm,UniquePtr<EVP_PKEY,EVP_PKEY_Delete> * pkey)82 keymaster_error_t convert_pkcs8_blob_to_evp(const uint8_t* key_data, size_t key_length,
83 keymaster_algorithm_t expected_algorithm,
84 UniquePtr<EVP_PKEY, EVP_PKEY_Delete>* pkey) {
85 if (key_data == NULL || key_length <= 0)
86 return KM_ERROR_INVALID_KEY_BLOB;
87
88 UniquePtr<PKCS8_PRIV_KEY_INFO, PKCS8_PRIV_KEY_INFO_Delete> pkcs8(
89 d2i_PKCS8_PRIV_KEY_INFO(NULL, &key_data, key_length));
90 if (pkcs8.get() == NULL)
91 return TranslateLastOpenSslError(true /* log_message */);
92
93 pkey->reset(EVP_PKCS82PKEY(pkcs8.get()));
94 if (!pkey->get())
95 return TranslateLastOpenSslError(true /* log_message */);
96
97 if (EVP_PKEY_type((*pkey)->type) != convert_to_evp(expected_algorithm)) {
98 LOG_E("EVP key algorithm was %d, not the expected %d", EVP_PKEY_type((*pkey)->type),
99 convert_to_evp(expected_algorithm));
100 return KM_ERROR_INVALID_KEY_BLOB;
101 }
102
103 return KM_ERROR_OK;
104 }
105
KeyMaterialToEvpKey(keymaster_key_format_t key_format,const KeymasterKeyBlob & key_material,keymaster_algorithm_t expected_algorithm,UniquePtr<EVP_PKEY,EVP_PKEY_Delete> * pkey)106 keymaster_error_t KeyMaterialToEvpKey(keymaster_key_format_t key_format,
107 const KeymasterKeyBlob& key_material,
108 keymaster_algorithm_t expected_algorithm,
109 UniquePtr<EVP_PKEY, EVP_PKEY_Delete>* pkey) {
110 if (key_format != KM_KEY_FORMAT_PKCS8)
111 return KM_ERROR_UNSUPPORTED_KEY_FORMAT;
112
113 return convert_pkcs8_blob_to_evp(key_material.key_material, key_material.key_material_size,
114 expected_algorithm, pkey);
115 }
116
EvpKeyToKeyMaterial(const EVP_PKEY * pkey,KeymasterKeyBlob * key_blob)117 keymaster_error_t EvpKeyToKeyMaterial(const EVP_PKEY* pkey, KeymasterKeyBlob* key_blob) {
118 int key_data_size = i2d_PrivateKey(pkey, NULL /* key_data*/);
119 if (key_data_size <= 0)
120 return TranslateLastOpenSslError();
121
122 if (!key_blob->Reset(key_data_size))
123 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
124
125 uint8_t* tmp = key_blob->writable_data();
126 i2d_PrivateKey(pkey, &tmp);
127
128 return KM_ERROR_OK;
129 }
130
ec_group_size_bits(EC_KEY * ec_key)131 size_t ec_group_size_bits(EC_KEY* ec_key) {
132 const EC_GROUP* group = EC_KEY_get0_group(ec_key);
133 UniquePtr<BN_CTX, BN_CTX_Delete> bn_ctx(BN_CTX_new());
134 UniquePtr<BIGNUM, BIGNUM_Delete> order(BN_new());
135 if (!EC_GROUP_get_order(group, order.get(), bn_ctx.get())) {
136 LOG_E("Failed to get EC group order", 0);
137 return 0;
138 }
139 return BN_num_bits(order.get());
140 }
141
142 } // namespace keymaster
143