1/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
2 * project 2006.
3 */
4/* ====================================================================
5 * Copyright (c) 2006 The OpenSSL Project. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 *
19 * 3. All advertising materials mentioning features or use of this
20 * software must display the following acknowledgment:
21 * "This product includes software developed by the OpenSSL Project
22 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
23 *
24 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
25 * endorse or promote products derived from this software without
26 * prior written permission. For written permission, please contact
27 * licensing@OpenSSL.org.
28 *
29 * 5. Products derived from this software may not be called "OpenSSL"
30 * nor may "OpenSSL" appear in their names without prior written
31 * permission of the OpenSSL Project.
32 *
33 * 6. Redistributions of any form whatsoever must retain the following
34 * acknowledgment:
35 * "This product includes software developed by the OpenSSL Project
36 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
37 *
38 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
39 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
40 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
41 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
42 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
44 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
45 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
46 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
47 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
49 * OF THE POSSIBILITY OF SUCH DAMAGE.
50 * ====================================================================
51 *
52 * This product includes cryptographic software written by Eric Young
53 * (eay@cryptsoft.com). This product includes software written by Tim
54 * Hudson (tjh@cryptsoft.com). */
55
56#include <openssl/evp.h>
57
58#include <openssl/bn.h>
59#include <openssl/bytestring.h>
60#include <openssl/ec.h>
61#include <openssl/ec_key.h>
62#include <openssl/ecdsa.h>
63#include <openssl/err.h>
64
65#include "internal.h"
66
67
68static int eckey_pub_encode(CBB *out, const EVP_PKEY *key) {
69 const EC_KEY *ec_key = key->pkey.ec;
70 const EC_GROUP *group = EC_KEY_get0_group(ec_key);
71 const EC_POINT *public_key = EC_KEY_get0_public_key(ec_key);
72
73 // See RFC 5480, section 2.
74 CBB spki, algorithm, oid, key_bitstring;
75 if (!CBB_add_asn1(out, &spki, CBS_ASN1_SEQUENCE) ||
76 !CBB_add_asn1(&spki, &algorithm, CBS_ASN1_SEQUENCE) ||
77 !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||
78 !CBB_add_bytes(&oid, ec_asn1_meth.oid, ec_asn1_meth.oid_len) ||
79 !EC_KEY_marshal_curve_name(&algorithm, group) ||
80 !CBB_add_asn1(&spki, &key_bitstring, CBS_ASN1_BITSTRING) ||
81 !CBB_add_u8(&key_bitstring, 0 /* padding */) ||
82 !EC_POINT_point2cbb(&key_bitstring, group, public_key,
83 POINT_CONVERSION_UNCOMPRESSED, NULL) ||
84 !CBB_flush(out)) {
85 OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);
86 return 0;
87 }
88
89 return 1;
90}
91
92static int eckey_pub_decode(EVP_PKEY *out, CBS *params, CBS *key) {
93 // See RFC 5480, section 2.
94
95 // The parameters are a named curve.
96 EC_POINT *point = NULL;
97 EC_KEY *eckey = NULL;
98 EC_GROUP *group = EC_KEY_parse_curve_name(params);
99 if (group == NULL || CBS_len(params) != 0) {
100 OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
101 goto err;
102 }
103
104 eckey = EC_KEY_new();
105 if (eckey == NULL || !EC_KEY_set_group(eckey, group)) {
106 goto err;
107 }
108
109 point = EC_POINT_new(group);
110 if (point == NULL ||
111 !EC_POINT_oct2point(group, point, CBS_data(key), CBS_len(key), NULL) ||
112 !EC_KEY_set_public_key(eckey, point)) {
113 goto err;
114 }
115
116 EC_GROUP_free(group);
117 EC_POINT_free(point);
118 EVP_PKEY_assign_EC_KEY(out, eckey);
119 return 1;
120
121err:
122 EC_GROUP_free(group);
123 EC_POINT_free(point);
124 EC_KEY_free(eckey);
125 return 0;
126}
127
128static int eckey_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b) {
129 int r;
130 const EC_GROUP *group = EC_KEY_get0_group(b->pkey.ec);
131 const EC_POINT *pa = EC_KEY_get0_public_key(a->pkey.ec),
132 *pb = EC_KEY_get0_public_key(b->pkey.ec);
133 r = EC_POINT_cmp(group, pa, pb, NULL);
134 if (r == 0) {
135 return 1;
136 } else if (r == 1) {
137 return 0;
138 } else {
139 return -2;
140 }
141}
142
143static int eckey_priv_decode(EVP_PKEY *out, CBS *params, CBS *key) {
144 // See RFC 5915.
145 EC_GROUP *group = EC_KEY_parse_parameters(params);
146 if (group == NULL || CBS_len(params) != 0) {
147 OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
148 EC_GROUP_free(group);
149 return 0;
150 }
151
152 EC_KEY *ec_key = EC_KEY_parse_private_key(key, group);
153 EC_GROUP_free(group);
154 if (ec_key == NULL || CBS_len(key) != 0) {
155 OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
156 EC_KEY_free(ec_key);
157 return 0;
158 }
159
160 EVP_PKEY_assign_EC_KEY(out, ec_key);
161 return 1;
162}
163
164static int eckey_priv_encode(CBB *out, const EVP_PKEY *key) {
165 const EC_KEY *ec_key = key->pkey.ec;
166
167 // Omit the redundant copy of the curve name. This contradicts RFC 5915 but
168 // aligns with PKCS #11. SEC 1 only says they may be omitted if known by other
169 // means. Both OpenSSL and NSS omit the redundant parameters, so we omit them
170 // as well.
171 unsigned enc_flags = EC_KEY_get_enc_flags(ec_key) | EC_PKEY_NO_PARAMETERS;
172
173 // See RFC 5915.
174 CBB pkcs8, algorithm, oid, private_key;
175 if (!CBB_add_asn1(out, &pkcs8, CBS_ASN1_SEQUENCE) ||
176 !CBB_add_asn1_uint64(&pkcs8, 0 /* version */) ||
177 !CBB_add_asn1(&pkcs8, &algorithm, CBS_ASN1_SEQUENCE) ||
178 !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||
179 !CBB_add_bytes(&oid, ec_asn1_meth.oid, ec_asn1_meth.oid_len) ||
180 !EC_KEY_marshal_curve_name(&algorithm, EC_KEY_get0_group(ec_key)) ||
181 !CBB_add_asn1(&pkcs8, &private_key, CBS_ASN1_OCTETSTRING) ||
182 !EC_KEY_marshal_private_key(&private_key, ec_key, enc_flags) ||
183 !CBB_flush(out)) {
184 OPENSSL_PUT_ERROR(EVP, EVP_R_ENCODE_ERROR);
185 return 0;
186 }
187
188 return 1;
189}
190
191static int int_ec_size(const EVP_PKEY *pkey) {
192 return ECDSA_size(pkey->pkey.ec);
193}
194
195static int ec_bits(const EVP_PKEY *pkey) {
196 const EC_GROUP *group = EC_KEY_get0_group(pkey->pkey.ec);
197 if (group == NULL) {
198 ERR_clear_error();
199 return 0;
200 }
201 return BN_num_bits(EC_GROUP_get0_order(group));
202}
203
204static int ec_missing_parameters(const EVP_PKEY *pkey) {
205 return EC_KEY_get0_group(pkey->pkey.ec) == NULL;
206}
207
208static int ec_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from) {
209 return EC_KEY_set_group(to->pkey.ec, EC_KEY_get0_group(from->pkey.ec));
210}
211
212static int ec_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b) {
213 const EC_GROUP *group_a = EC_KEY_get0_group(a->pkey.ec),
214 *group_b = EC_KEY_get0_group(b->pkey.ec);
215 if (EC_GROUP_cmp(group_a, group_b, NULL) != 0) {
216 // mismatch
217 return 0;
218 }
219 return 1;
220}
221
222static void int_ec_free(EVP_PKEY *pkey) { EC_KEY_free(pkey->pkey.ec); }
223
224static int eckey_opaque(const EVP_PKEY *pkey) {
225 return EC_KEY_is_opaque(pkey->pkey.ec);
226}
227
228const EVP_PKEY_ASN1_METHOD ec_asn1_meth = {
229 EVP_PKEY_EC,
230 // 1.2.840.10045.2.1
231 {0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, 0x01}, 7,
232
233 eckey_pub_decode,
234 eckey_pub_encode,
235 eckey_pub_cmp,
236
237 eckey_priv_decode,
238 eckey_priv_encode,
239
240 NULL /* set_priv_raw */,
241 NULL /* set_pub_raw */,
242 NULL /* get_priv_raw */,
243 NULL /* get_pub_raw */,
244
245 eckey_opaque,
246
247 int_ec_size,
248 ec_bits,
249
250 ec_missing_parameters,
251 ec_copy_parameters,
252 ec_cmp_parameters,
253
254 int_ec_free,
255};
256