1 /* $OpenBSD: gostr341001.c,v 1.3 2015/02/11 03:19:37 doug 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 "gost_locl.h"
61 
62 /* Convert little-endian byte array into bignum */
63 BIGNUM *
64 GOST_le2bn(const unsigned char *buf, size_t len, BIGNUM *bn)
65 {
66 	unsigned char temp[64];
67 	int i;
68 
69 	if (len > 64)
70 		return NULL;
71 
72 	for (i = 0; i < len; i++) {
73 		temp[len - 1 - i] = buf[i];
74 	}
75 
76 	return BN_bin2bn(temp, len, bn);
77 }
78 
79 int
80 GOST_bn2le(BIGNUM *bn, unsigned char *buf, int len)
81 {
82 	unsigned char temp[64];
83 	int i, bytes;
84 
85 	bytes = BN_num_bytes(bn);
86 	if (len > 64 || bytes > len)
87 		return 0;
88 
89 	BN_bn2bin(bn, temp);
90 
91 	for (i = 0; i < bytes; i++) {
92 		buf[bytes - 1 - i] = temp[i];
93 	}
94 
95 	memset(buf + bytes, 0, len - bytes);
96 
97 	return 1;
98 }
99 
100 int
101 gost2001_compute_public(GOST_KEY *ec)
102 {
103 	const EC_GROUP *group = GOST_KEY_get0_group(ec);
104 	EC_POINT *pub_key = NULL;
105 	const BIGNUM *priv_key = NULL;
106 	BN_CTX *ctx = NULL;
107 	int ok = 0;
108 
109 	if (group == NULL) {
110 		GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,
111 		    GOST_R_KEY_IS_NOT_INITIALIZED);
112 		return 0;
113 	}
114 	ctx = BN_CTX_new();
115 	if (ctx == NULL) {
116 		GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,
117 		    ERR_R_MALLOC_FAILURE);
118 		return 0;
119 	}
120 	BN_CTX_start(ctx);
121 	if ((priv_key = GOST_KEY_get0_private_key(ec)) == NULL)
122 		goto err;
123 
124 	pub_key = EC_POINT_new(group);
125 	if (pub_key == NULL)
126 		goto err;
127 	if (EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx) == 0)
128 		goto err;
129 	if (GOST_KEY_set_public_key(ec, pub_key) == 0)
130 		goto err;
131 	ok = 1;
132 
133 	if (ok == 0) {
134 err:
135 		GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC, ERR_R_EC_LIB);
136 	}
137 	EC_POINT_free(pub_key);
138 	if (ctx != NULL) {
139 		BN_CTX_end(ctx);
140 		BN_CTX_free(ctx);
141 	}
142 	return ok;
143 }
144 
145 ECDSA_SIG *
146 gost2001_do_sign(BIGNUM *md, GOST_KEY *eckey)
147 {
148 	ECDSA_SIG *newsig = NULL;
149 	BIGNUM *order = NULL;
150 	const EC_GROUP *group;
151 	const BIGNUM *priv_key;
152 	BIGNUM *r = NULL, *s = NULL, *X = NULL, *tmp = NULL, *tmp2 = NULL, *k =
153 	    NULL, *e = NULL;
154 	EC_POINT *C = NULL;
155 	BN_CTX *ctx = BN_CTX_new();
156 	int ok = 0;
157 
158 	if (ctx == NULL) {
159 		GOSTerr(GOST_F_GOST2001_DO_SIGN, ERR_R_MALLOC_FAILURE);
160 		return NULL;
161 	}
162 	BN_CTX_start(ctx);
163 	newsig = ECDSA_SIG_new();
164 	if (newsig == NULL) {
165 		GOSTerr(GOST_F_GOST2001_DO_SIGN, ERR_R_MALLOC_FAILURE);
166 		goto err;
167 	}
168 	s = newsig->s;
169 	r = newsig->r;
170 	group = GOST_KEY_get0_group(eckey);
171 	if ((order = BN_CTX_get(ctx)) == NULL)
172 		goto err;
173 	if (EC_GROUP_get_order(group, order, ctx) == 0)
174 		goto err;
175 	priv_key = GOST_KEY_get0_private_key(eckey);
176 	if ((e = BN_CTX_get(ctx)) == NULL)
177 		goto err;
178 	if (BN_mod(e, md, order, ctx) == 0)
179 		goto err;
180 	if (BN_is_zero(e))
181 		BN_one(e);
182 	if ((k = BN_CTX_get(ctx)) == NULL)
183 		goto err;
184 	if ((X = BN_CTX_get(ctx)) == NULL)
185 		goto err;
186 	if ((C = EC_POINT_new(group)) == NULL)
187 		goto err;
188 	do {
189 		do {
190 			if (!BN_rand_range(k, order)) {
191 				GOSTerr(GOST_F_GOST2001_DO_SIGN,
192 					GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
193 				goto err;
194 			}
195 			/*
196 			 * We do not want timing information to leak the length
197 			 * of k, so we compute G*k using an equivalent scalar
198 			 * of fixed bit-length.
199 			 */
200 			if (BN_add(k, k, order) == 0)
201 				goto err;
202 			if (BN_num_bits(k) <= BN_num_bits(order))
203 				if (BN_add(k, k, order) == 0)
204 					goto err;
205 
206 			if (EC_POINT_mul(group, C, k, NULL, NULL, ctx) == 0) {
207 				GOSTerr(GOST_F_GOST2001_DO_SIGN, ERR_R_EC_LIB);
208 				goto err;
209 			}
210 			if (EC_POINT_get_affine_coordinates_GFp(group, C, X,
211 			    NULL, ctx) == 0) {
212 				GOSTerr(GOST_F_GOST2001_DO_SIGN, ERR_R_EC_LIB);
213 				goto err;
214 			}
215 			if (BN_nnmod(r, X, order, ctx) == 0)
216 				goto err;
217 		} while (BN_is_zero(r));
218 		/* s = (r*priv_key+k*e) mod order */
219 		if (tmp == NULL) {
220 			if ((tmp = BN_CTX_get(ctx)) == NULL)
221 				goto err;
222 		}
223 		if (BN_mod_mul(tmp, priv_key, r, order, ctx) == 0)
224 			goto err;
225 		if (tmp2 == NULL) {
226 			if ((tmp2 = BN_CTX_get(ctx)) == NULL)
227 				goto err;
228 		}
229 		if (BN_mod_mul(tmp2, k, e, order, ctx) == 0)
230 			goto err;
231 		if (BN_mod_add(s, tmp, tmp2, order, ctx) == 0)
232 			goto err;
233 	} while (BN_is_zero(s));
234 	ok = 1;
235 
236 err:
237 	EC_POINT_free(C);
238 	if (ctx != NULL) {
239 		BN_CTX_end(ctx);
240 		BN_CTX_free(ctx);
241 	}
242 	if (ok == 0) {
243 		ECDSA_SIG_free(newsig);
244 		newsig = NULL;
245 	}
246 	return newsig;
247 }
248 
249 int
250 gost2001_do_verify(BIGNUM *md, ECDSA_SIG *sig, GOST_KEY *ec)
251 {
252 	BN_CTX *ctx = BN_CTX_new();
253 	const EC_GROUP *group = GOST_KEY_get0_group(ec);
254 	BIGNUM *order;
255 	BIGNUM *e = NULL, *R = NULL, *v = NULL, *z1 = NULL, *z2 = NULL;
256 	BIGNUM *X = NULL, *tmp = NULL;
257 	EC_POINT *C = NULL;
258 	const EC_POINT *pub_key = NULL;
259 	int ok = 0;
260 
261 	if (ctx == NULL)
262 		goto err;
263 	BN_CTX_start(ctx);
264 	if ((order = BN_CTX_get(ctx)) == NULL)
265 		goto err;
266 	if ((e = BN_CTX_get(ctx)) == NULL)
267 		goto err;
268 	if ((z1 = BN_CTX_get(ctx)) == NULL)
269 		goto err;
270 	if ((z2 = BN_CTX_get(ctx)) == NULL)
271 		goto err;
272 	if ((tmp = BN_CTX_get(ctx)) == NULL)
273 		goto err;
274 	if ((X = BN_CTX_get(ctx)) == NULL)
275 		goto err;
276 	if ((R = BN_CTX_get(ctx)) == NULL)
277 		goto err;
278 	if ((v = BN_CTX_get(ctx)) == NULL)
279 		goto err;
280 
281 	if (EC_GROUP_get_order(group, order, ctx) == 0)
282 		goto err;
283 	pub_key = GOST_KEY_get0_public_key(ec);
284 	if (BN_is_zero(sig->s) || BN_is_zero(sig->r) ||
285 	    BN_cmp(sig->s, order) >= 1 || BN_cmp(sig->r, order) >= 1) {
286 		GOSTerr(GOST_F_GOST2001_DO_VERIFY,
287 		    GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
288 		goto err;
289 	}
290 
291 	if (BN_mod(e, md, order, ctx) == 0)
292 		goto err;
293 	if (BN_is_zero(e))
294 		BN_one(e);
295 	if ((v = BN_mod_inverse(v, e, order, ctx)) == NULL)
296 		goto err;
297 	if (BN_mod_mul(z1, sig->s, v, order, ctx) == 0)
298 		goto err;
299 	if (BN_sub(tmp, order, sig->r) == 0)
300 		goto err;
301 	if (BN_mod_mul(z2, tmp, v, order, ctx) == 0)
302 		goto err;
303 	if ((C = EC_POINT_new(group)) == NULL)
304 		goto err;
305 	if (EC_POINT_mul(group, C, z1, pub_key, z2, ctx) == 0) {
306 		GOSTerr(GOST_F_GOST2001_DO_VERIFY, ERR_R_EC_LIB);
307 		goto err;
308 	}
309 	if (EC_POINT_get_affine_coordinates_GFp(group, C, X, NULL, ctx) == 0) {
310 		GOSTerr(GOST_F_GOST2001_DO_VERIFY, ERR_R_EC_LIB);
311 		goto err;
312 	}
313 	if (BN_mod(R, X, order, ctx) == 0)
314 		goto err;
315 	if (BN_cmp(R, sig->r) != 0) {
316 		GOSTerr(GOST_F_GOST2001_DO_VERIFY, GOST_R_SIGNATURE_MISMATCH);
317 	} else {
318 		ok = 1;
319 	}
320 err:
321 	EC_POINT_free(C);
322 	if (ctx != NULL) {
323 		BN_CTX_end(ctx);
324 		BN_CTX_free(ctx);
325 	}
326 	return ok;
327 }
328 
329 /* Implementation of CryptoPro VKO 34.10-2001 algorithm */
330 int
331 VKO_compute_key(BIGNUM *X, BIGNUM *Y, const GOST_KEY *pkey, GOST_KEY *priv_key,
332     const BIGNUM *ukm)
333 {
334 	BIGNUM *p = NULL, *order = NULL;
335 	const BIGNUM *key = GOST_KEY_get0_private_key(priv_key);
336 	const EC_GROUP *group = GOST_KEY_get0_group(priv_key);
337 	const EC_POINT *pub_key = GOST_KEY_get0_public_key(pkey);
338 	EC_POINT *pnt;
339 	BN_CTX *ctx = NULL;
340 	int ok = 0;
341 
342 	pnt = EC_POINT_new(group);
343 	if (pnt == NULL)
344 		goto err;
345 	ctx = BN_CTX_new();
346 	if (ctx == NULL)
347 		goto err;
348 	BN_CTX_start(ctx);
349 	if ((p = BN_CTX_get(ctx)) == NULL)
350 		goto err;
351 	if ((order = BN_CTX_get(ctx)) == NULL)
352 		goto err;
353 	if (EC_GROUP_get_order(group, order, ctx) == 0)
354 		goto err;
355 	if (BN_mod_mul(p, key, ukm, order, ctx) == 0)
356 		goto err;
357 	if (EC_POINT_mul(group, pnt, NULL, pub_key, p, ctx) == 0)
358 		goto err;
359 	if (EC_POINT_get_affine_coordinates_GFp(group, pnt, X, Y, ctx) == 0)
360 		goto err;
361 	ok = 1;
362 
363 err:
364 	if (ctx != NULL) {
365 		BN_CTX_end(ctx);
366 		BN_CTX_free(ctx);
367 	}
368 	EC_POINT_free(pnt);
369 	return ok;
370 }
371 
372 int
373 gost2001_keygen(GOST_KEY *ec)
374 {
375 	BIGNUM *order = BN_new(), *d = BN_new();
376 	const EC_GROUP *group = GOST_KEY_get0_group(ec);
377 	int rc = 0;
378 
379 	if (order == NULL || d == NULL)
380 		goto err;
381 	if (EC_GROUP_get_order(group, order, NULL) == 0)
382 		goto err;
383 
384 	do {
385 		if (BN_rand_range(d, order) == 0) {
386 			GOSTerr(GOST_F_GOST2001_KEYGEN,
387 				GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
388 			goto err;
389 		}
390 	} while (BN_is_zero(d));
391 
392 	if (GOST_KEY_set_private_key(ec, d) == 0)
393 		goto err;
394 	rc = gost2001_compute_public(ec);
395 
396 err:
397 	BN_free(d);
398 	BN_free(order);
399 	return rc;
400 }
401 #endif
402