1 /* $OpenBSD: gostr341001_key.c,v 1.9 2021/04/20 17:16:38 tb Exp $ */
2 /*
3  * Copyright (c) 2014 Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
4  * Copyright (c) 2005-2006 Cryptocom LTD
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  *
18  * 3. All advertising materials mentioning features or use of this
19  *    software must display the following acknowledgment:
20  *    "This product includes software developed by the OpenSSL Project
21  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
22  *
23  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
24  *    endorse or promote products derived from this software without
25  *    prior written permission. For written permission, please contact
26  *    openssl-core@openssl.org.
27  *
28  * 5. Products derived from this software may not be called "OpenSSL"
29  *    nor may "OpenSSL" appear in their names without prior written
30  *    permission of the OpenSSL Project.
31  *
32  * 6. Redistributions of any form whatsoever must retain the following
33  *    acknowledgment:
34  *    "This product includes software developed by the OpenSSL Project
35  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
36  *
37  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
38  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
40  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
43  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
44  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
45  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
46  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
47  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
48  * OF THE POSSIBILITY OF SUCH DAMAGE.
49  * ====================================================================
50  */
51 
52 #include <string.h>
53 
54 #include <openssl/opensslconf.h>
55 
56 #ifndef OPENSSL_NO_GOST
57 #include <openssl/bn.h>
58 #include <openssl/err.h>
59 #include <openssl/gost.h>
60 #include <openssl/objects.h>
61 #include "gost_locl.h"
62 
63 struct gost_key_st {
64 	EC_GROUP *group;
65 
66 	EC_POINT *pub_key;
67 	BIGNUM	 *priv_key;
68 
69 	int	references;
70 
71 	int digest_nid;
72 };
73 
74 GOST_KEY *
GOST_KEY_new(void)75 GOST_KEY_new(void)
76 {
77 	GOST_KEY *ret;
78 
79 	ret = malloc(sizeof(GOST_KEY));
80 	if (ret == NULL) {
81 		GOSTerror(ERR_R_MALLOC_FAILURE);
82 		return (NULL);
83 	}
84 	ret->group = NULL;
85 	ret->pub_key = NULL;
86 	ret->priv_key = NULL;
87 	ret->references = 1;
88 	ret->digest_nid = NID_undef;
89 	return (ret);
90 }
91 
92 void
GOST_KEY_free(GOST_KEY * r)93 GOST_KEY_free(GOST_KEY *r)
94 {
95 	int i;
96 
97 	if (r == NULL)
98 		return;
99 
100 	i = CRYPTO_add(&r->references, -1, CRYPTO_LOCK_EC);
101 	if (i > 0)
102 		return;
103 
104 	EC_GROUP_free(r->group);
105 	EC_POINT_free(r->pub_key);
106 	BN_clear_free(r->priv_key);
107 
108 	freezero(r, sizeof(GOST_KEY));
109 }
110 
111 int
GOST_KEY_check_key(const GOST_KEY * key)112 GOST_KEY_check_key(const GOST_KEY *key)
113 {
114 	int ok = 0;
115 	BN_CTX *ctx = NULL;
116 	BIGNUM *order = NULL;
117 	EC_POINT *point = NULL;
118 
119 	if (key == NULL || key->group == NULL || key->pub_key == NULL) {
120 		GOSTerror(ERR_R_PASSED_NULL_PARAMETER);
121 		return 0;
122 	}
123 	if (EC_POINT_is_at_infinity(key->group, key->pub_key) != 0) {
124 		GOSTerror(EC_R_POINT_AT_INFINITY);
125 		goto err;
126 	}
127 	if ((ctx = BN_CTX_new()) == NULL)
128 		goto err;
129 	if ((point = EC_POINT_new(key->group)) == NULL)
130 		goto err;
131 
132 	/* testing whether the pub_key is on the elliptic curve */
133 	if (EC_POINT_is_on_curve(key->group, key->pub_key, ctx) == 0) {
134 		GOSTerror(EC_R_POINT_IS_NOT_ON_CURVE);
135 		goto err;
136 	}
137 	/* testing whether pub_key * order is the point at infinity */
138 	if ((order = BN_new()) == NULL)
139 		goto err;
140 	if (EC_GROUP_get_order(key->group, order, ctx) == 0) {
141 		GOSTerror(EC_R_INVALID_GROUP_ORDER);
142 		goto err;
143 	}
144 	if (EC_POINT_mul(key->group, point, NULL, key->pub_key, order,
145 	    ctx) == 0) {
146 		GOSTerror(ERR_R_EC_LIB);
147 		goto err;
148 	}
149 	if (EC_POINT_is_at_infinity(key->group, point) == 0) {
150 		GOSTerror(EC_R_WRONG_ORDER);
151 		goto err;
152 	}
153 	/*
154 	 * in case the priv_key is present : check if generator * priv_key ==
155 	 * pub_key
156 	 */
157 	if (key->priv_key != NULL) {
158 		if (BN_cmp(key->priv_key, order) >= 0) {
159 			GOSTerror(EC_R_WRONG_ORDER);
160 			goto err;
161 		}
162 		if (EC_POINT_mul(key->group, point, key->priv_key, NULL, NULL,
163 		    ctx) == 0) {
164 			GOSTerror(ERR_R_EC_LIB);
165 			goto err;
166 		}
167 		if (EC_POINT_cmp(key->group, point, key->pub_key, ctx) != 0) {
168 			GOSTerror(EC_R_INVALID_PRIVATE_KEY);
169 			goto err;
170 		}
171 	}
172 	ok = 1;
173 err:
174 	BN_free(order);
175 	BN_CTX_free(ctx);
176 	EC_POINT_free(point);
177 	return (ok);
178 }
179 
180 int
GOST_KEY_set_public_key_affine_coordinates(GOST_KEY * key,BIGNUM * x,BIGNUM * y)181 GOST_KEY_set_public_key_affine_coordinates(GOST_KEY *key, BIGNUM *x, BIGNUM *y)
182 {
183 	BN_CTX *ctx = NULL;
184 	BIGNUM *tx, *ty;
185 	EC_POINT *point = NULL;
186 	int ok = 0;
187 
188 	if (key == NULL || key->group == NULL || x == NULL || y == NULL) {
189 		GOSTerror(ERR_R_PASSED_NULL_PARAMETER);
190 		return 0;
191 	}
192 	ctx = BN_CTX_new();
193 	if (ctx == NULL)
194 		goto err;
195 
196 	point = EC_POINT_new(key->group);
197 	if (point == NULL)
198 		goto err;
199 
200 	if ((tx = BN_CTX_get(ctx)) == NULL)
201 		goto err;
202 	if ((ty = BN_CTX_get(ctx)) == NULL)
203 		goto err;
204 	if (EC_POINT_set_affine_coordinates(key->group, point, x, y,
205 	    ctx) == 0)
206 		goto err;
207 	if (EC_POINT_get_affine_coordinates(key->group, point, tx, ty,
208 	    ctx) == 0)
209 		goto err;
210 	/*
211 	 * Check if retrieved coordinates match originals: if not, values are
212 	 * out of range.
213 	 */
214 	if (BN_cmp(x, tx) != 0 || BN_cmp(y, ty) != 0) {
215 		GOSTerror(EC_R_COORDINATES_OUT_OF_RANGE);
216 		goto err;
217 	}
218 	if (GOST_KEY_set_public_key(key, point) == 0)
219 		goto err;
220 
221 	if (GOST_KEY_check_key(key) == 0)
222 		goto err;
223 
224 	ok = 1;
225 
226 err:
227 	EC_POINT_free(point);
228 	BN_CTX_free(ctx);
229 	return ok;
230 
231 }
232 
233 const EC_GROUP *
GOST_KEY_get0_group(const GOST_KEY * key)234 GOST_KEY_get0_group(const GOST_KEY *key)
235 {
236 	return key->group;
237 }
238 
239 int
GOST_KEY_set_group(GOST_KEY * key,const EC_GROUP * group)240 GOST_KEY_set_group(GOST_KEY *key, const EC_GROUP *group)
241 {
242 	EC_GROUP_free(key->group);
243 	key->group = EC_GROUP_dup(group);
244 	return (key->group == NULL) ? 0 : 1;
245 }
246 
247 const BIGNUM *
GOST_KEY_get0_private_key(const GOST_KEY * key)248 GOST_KEY_get0_private_key(const GOST_KEY *key)
249 {
250 	return key->priv_key;
251 }
252 
253 int
GOST_KEY_set_private_key(GOST_KEY * key,const BIGNUM * priv_key)254 GOST_KEY_set_private_key(GOST_KEY *key, const BIGNUM *priv_key)
255 {
256 	BN_clear_free(key->priv_key);
257 	key->priv_key = BN_dup(priv_key);
258 	return (key->priv_key == NULL) ? 0 : 1;
259 }
260 
261 const EC_POINT *
GOST_KEY_get0_public_key(const GOST_KEY * key)262 GOST_KEY_get0_public_key(const GOST_KEY *key)
263 {
264 	return key->pub_key;
265 }
266 
267 int
GOST_KEY_set_public_key(GOST_KEY * key,const EC_POINT * pub_key)268 GOST_KEY_set_public_key(GOST_KEY *key, const EC_POINT *pub_key)
269 {
270 	EC_POINT_free(key->pub_key);
271 	key->pub_key = EC_POINT_dup(pub_key, key->group);
272 	return (key->pub_key == NULL) ? 0 : 1;
273 }
274 
275 int
GOST_KEY_get_digest(const GOST_KEY * key)276 GOST_KEY_get_digest(const GOST_KEY *key)
277 {
278 	return key->digest_nid;
279 }
280 int
GOST_KEY_set_digest(GOST_KEY * key,int digest_nid)281 GOST_KEY_set_digest(GOST_KEY *key, int digest_nid)
282 {
283 	if (digest_nid == NID_id_GostR3411_94_CryptoProParamSet ||
284 	    digest_nid == NID_id_tc26_gost3411_2012_256 ||
285 	    digest_nid == NID_id_tc26_gost3411_2012_512) {
286 		key->digest_nid = digest_nid;
287 		return 1;
288 	}
289 
290 	return 0;
291 }
292 
293 size_t
GOST_KEY_get_size(const GOST_KEY * r)294 GOST_KEY_get_size(const GOST_KEY *r)
295 {
296 	int i;
297 	BIGNUM *order = NULL;
298 	const EC_GROUP *group;
299 
300 	if (r == NULL)
301 		return 0;
302 	group = GOST_KEY_get0_group(r);
303 	if (group == NULL)
304 		return 0;
305 
306 	if ((order = BN_new()) == NULL)
307 		return 0;
308 
309 	if (EC_GROUP_get_order(group, order, NULL) == 0) {
310 		BN_clear_free(order);
311 		return 0;
312 	}
313 
314 	i = BN_num_bytes(order);
315 	BN_clear_free(order);
316 	return (i);
317 }
318 #endif
319