1 /* $OpenBSD: ec_key.c,v 1.26 2021/04/20 17:23:37 tb Exp $ */
2 /*
3 * Written by Nils Larsch for the OpenSSL project.
4 */
5 /* ====================================================================
6 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24 *
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@openssl.org.
29 *
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
33 *
34 * 6. Redistributions of any form whatsoever must retain the following
35 * acknowledgment:
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
52 *
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
56 *
57 */
58 /* ====================================================================
59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60 * Portions originally developed by SUN MICROSYSTEMS, INC., and
61 * contributed to the OpenSSL project.
62 */
63
64 #include <string.h>
65
66 #include <openssl/opensslconf.h>
67
68 #ifndef OPENSSL_NO_ENGINE
69 #include <openssl/engine.h>
70 #endif
71 #include <openssl/err.h>
72
73 #include "bn_lcl.h"
74 #include "ec_lcl.h"
75
76 EC_KEY *
EC_KEY_new(void)77 EC_KEY_new(void)
78 {
79 return EC_KEY_new_method(NULL);
80 }
81
82 EC_KEY *
EC_KEY_new_by_curve_name(int nid)83 EC_KEY_new_by_curve_name(int nid)
84 {
85 EC_KEY *ret = EC_KEY_new();
86 if (ret == NULL)
87 return NULL;
88 ret->group = EC_GROUP_new_by_curve_name(nid);
89 if (ret->group == NULL) {
90 EC_KEY_free(ret);
91 return NULL;
92 }
93 if (ret->meth->set_group != NULL &&
94 ret->meth->set_group(ret, ret->group) == 0) {
95 EC_KEY_free(ret);
96 return NULL;
97 }
98 return ret;
99 }
100
101 void
EC_KEY_free(EC_KEY * r)102 EC_KEY_free(EC_KEY * r)
103 {
104 int i;
105
106 if (r == NULL)
107 return;
108
109 i = CRYPTO_add(&r->references, -1, CRYPTO_LOCK_EC);
110 if (i > 0)
111 return;
112
113 if (r->meth != NULL && r->meth->finish != NULL)
114 r->meth->finish(r);
115
116 #ifndef OPENSSL_NO_ENGINE
117 ENGINE_finish(r->engine);
118 #endif
119 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_EC_KEY, r, &r->ex_data);
120
121 EC_GROUP_free(r->group);
122 EC_POINT_free(r->pub_key);
123 BN_clear_free(r->priv_key);
124
125 EC_EX_DATA_free_all_data(&r->method_data);
126
127 freezero(r, sizeof(EC_KEY));
128 }
129
130 EC_KEY *
EC_KEY_copy(EC_KEY * dest,const EC_KEY * src)131 EC_KEY_copy(EC_KEY * dest, const EC_KEY * src)
132 {
133 EC_EXTRA_DATA *d;
134
135 if (dest == NULL || src == NULL) {
136 ECerror(ERR_R_PASSED_NULL_PARAMETER);
137 return NULL;
138 }
139 if (src->meth != dest->meth) {
140 if (dest->meth != NULL && dest->meth->finish != NULL)
141 dest->meth->finish(dest);
142 #ifndef OPENSSL_NO_ENGINE
143 if (ENGINE_finish(dest->engine) == 0)
144 return 0;
145 dest->engine = NULL;
146 #endif
147 }
148 /* copy the parameters */
149 if (src->group) {
150 const EC_METHOD *meth = EC_GROUP_method_of(src->group);
151 /* clear the old group */
152 EC_GROUP_free(dest->group);
153 dest->group = EC_GROUP_new(meth);
154 if (dest->group == NULL)
155 return NULL;
156 if (!EC_GROUP_copy(dest->group, src->group))
157 return NULL;
158 }
159 /* copy the public key */
160 if (src->pub_key && src->group) {
161 EC_POINT_free(dest->pub_key);
162 dest->pub_key = EC_POINT_new(src->group);
163 if (dest->pub_key == NULL)
164 return NULL;
165 if (!EC_POINT_copy(dest->pub_key, src->pub_key))
166 return NULL;
167 }
168 /* copy the private key */
169 if (src->priv_key) {
170 if (dest->priv_key == NULL) {
171 dest->priv_key = BN_new();
172 if (dest->priv_key == NULL)
173 return NULL;
174 }
175 if (!BN_copy(dest->priv_key, src->priv_key))
176 return NULL;
177 }
178 /* copy method/extra data */
179 EC_EX_DATA_free_all_data(&dest->method_data);
180
181 for (d = src->method_data; d != NULL; d = d->next) {
182 void *t = d->dup_func(d->data);
183
184 if (t == NULL)
185 return 0;
186 if (!EC_EX_DATA_set_data(&dest->method_data, t, d->dup_func,
187 d->free_func, d->clear_free_func))
188 return 0;
189 }
190
191 /* copy the rest */
192 dest->enc_flag = src->enc_flag;
193 dest->conv_form = src->conv_form;
194 dest->version = src->version;
195 dest->flags = src->flags;
196
197 if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_EC_KEY, &dest->ex_data,
198 &((EC_KEY *)src)->ex_data)) /* XXX const */
199 return NULL;
200
201 if (src->meth != dest->meth) {
202 #ifndef OPENSSL_NO_ENGINE
203 if (src->engine != NULL && ENGINE_init(src->engine) == 0)
204 return 0;
205 dest->engine = src->engine;
206 #endif
207 dest->meth = src->meth;
208 }
209
210 if (src->meth != NULL && src->meth->copy != NULL &&
211 src->meth->copy(dest, src) == 0)
212 return 0;
213
214 return dest;
215 }
216
217 EC_KEY *
EC_KEY_dup(const EC_KEY * ec_key)218 EC_KEY_dup(const EC_KEY * ec_key)
219 {
220 EC_KEY *ret;
221
222 if ((ret = EC_KEY_new_method(ec_key->engine)) == NULL)
223 return NULL;
224 if (EC_KEY_copy(ret, ec_key) == NULL) {
225 EC_KEY_free(ret);
226 return NULL;
227 }
228 return ret;
229 }
230
231 int
EC_KEY_up_ref(EC_KEY * r)232 EC_KEY_up_ref(EC_KEY * r)
233 {
234 int i = CRYPTO_add(&r->references, 1, CRYPTO_LOCK_EC);
235 return ((i > 1) ? 1 : 0);
236 }
237
238 int
EC_KEY_set_ex_data(EC_KEY * r,int idx,void * arg)239 EC_KEY_set_ex_data(EC_KEY *r, int idx, void *arg)
240 {
241 return CRYPTO_set_ex_data(&r->ex_data, idx, arg);
242 }
243
244 void *
EC_KEY_get_ex_data(const EC_KEY * r,int idx)245 EC_KEY_get_ex_data(const EC_KEY *r, int idx)
246 {
247 return CRYPTO_get_ex_data(&r->ex_data, idx);
248 }
249
250 int
EC_KEY_generate_key(EC_KEY * eckey)251 EC_KEY_generate_key(EC_KEY *eckey)
252 {
253 if (eckey->meth->keygen != NULL)
254 return eckey->meth->keygen(eckey);
255 ECerror(EC_R_NOT_IMPLEMENTED);
256 return 0;
257 }
258
259 int
ossl_ec_key_gen(EC_KEY * eckey)260 ossl_ec_key_gen(EC_KEY *eckey)
261 {
262 int ok = 0;
263 BN_CTX *ctx = NULL;
264 BIGNUM *priv_key = NULL, *order = NULL;
265 EC_POINT *pub_key = NULL;
266
267 if (!eckey || !eckey->group) {
268 ECerror(ERR_R_PASSED_NULL_PARAMETER);
269 return 0;
270 }
271
272 if ((order = BN_new()) == NULL)
273 goto err;
274 if ((ctx = BN_CTX_new()) == NULL)
275 goto err;
276
277 if ((priv_key = eckey->priv_key) == NULL) {
278 if ((priv_key = BN_new()) == NULL)
279 goto err;
280 }
281
282 if (!EC_GROUP_get_order(eckey->group, order, ctx))
283 goto err;
284
285 if (!bn_rand_interval(priv_key, BN_value_one(), order))
286 goto err;
287
288 if ((pub_key = eckey->pub_key) == NULL) {
289 if ((pub_key = EC_POINT_new(eckey->group)) == NULL)
290 goto err;
291 }
292
293 if (!EC_POINT_mul(eckey->group, pub_key, priv_key, NULL, NULL, ctx))
294 goto err;
295
296 eckey->priv_key = priv_key;
297 eckey->pub_key = pub_key;
298
299 ok = 1;
300
301 err:
302 BN_free(order);
303 if (eckey->pub_key == NULL)
304 EC_POINT_free(pub_key);
305 if (eckey->priv_key == NULL)
306 BN_free(priv_key);
307 BN_CTX_free(ctx);
308 return (ok);
309 }
310
311 int
EC_KEY_check_key(const EC_KEY * eckey)312 EC_KEY_check_key(const EC_KEY * eckey)
313 {
314 int ok = 0;
315 BN_CTX *ctx = NULL;
316 const BIGNUM *order = NULL;
317 EC_POINT *point = NULL;
318
319 if (!eckey || !eckey->group || !eckey->pub_key) {
320 ECerror(ERR_R_PASSED_NULL_PARAMETER);
321 return 0;
322 }
323 if (EC_POINT_is_at_infinity(eckey->group, eckey->pub_key) > 0) {
324 ECerror(EC_R_POINT_AT_INFINITY);
325 goto err;
326 }
327 if ((ctx = BN_CTX_new()) == NULL)
328 goto err;
329 if ((point = EC_POINT_new(eckey->group)) == NULL)
330 goto err;
331
332 /* testing whether the pub_key is on the elliptic curve */
333 if (EC_POINT_is_on_curve(eckey->group, eckey->pub_key, ctx) <= 0) {
334 ECerror(EC_R_POINT_IS_NOT_ON_CURVE);
335 goto err;
336 }
337 /* testing whether pub_key * order is the point at infinity */
338 order = &eckey->group->order;
339 if (BN_is_zero(order)) {
340 ECerror(EC_R_INVALID_GROUP_ORDER);
341 goto err;
342 }
343 if (!EC_POINT_mul(eckey->group, point, NULL, eckey->pub_key, order, ctx)) {
344 ECerror(ERR_R_EC_LIB);
345 goto err;
346 }
347 if (EC_POINT_is_at_infinity(eckey->group, point) <= 0) {
348 ECerror(EC_R_WRONG_ORDER);
349 goto err;
350 }
351 /*
352 * in case the priv_key is present : check if generator * priv_key ==
353 * pub_key
354 */
355 if (eckey->priv_key) {
356 if (BN_cmp(eckey->priv_key, order) >= 0) {
357 ECerror(EC_R_WRONG_ORDER);
358 goto err;
359 }
360 if (!EC_POINT_mul(eckey->group, point, eckey->priv_key,
361 NULL, NULL, ctx)) {
362 ECerror(ERR_R_EC_LIB);
363 goto err;
364 }
365 if (EC_POINT_cmp(eckey->group, point, eckey->pub_key,
366 ctx) != 0) {
367 ECerror(EC_R_INVALID_PRIVATE_KEY);
368 goto err;
369 }
370 }
371 ok = 1;
372 err:
373 BN_CTX_free(ctx);
374 EC_POINT_free(point);
375 return (ok);
376 }
377
378 int
EC_KEY_set_public_key_affine_coordinates(EC_KEY * key,BIGNUM * x,BIGNUM * y)379 EC_KEY_set_public_key_affine_coordinates(EC_KEY * key, BIGNUM * x, BIGNUM * y)
380 {
381 BN_CTX *ctx = NULL;
382 BIGNUM *tx, *ty;
383 EC_POINT *point = NULL;
384 int ok = 0;
385
386 if (!key || !key->group || !x || !y) {
387 ECerror(ERR_R_PASSED_NULL_PARAMETER);
388 return 0;
389 }
390 ctx = BN_CTX_new();
391 if (!ctx)
392 goto err;
393
394 point = EC_POINT_new(key->group);
395
396 if (!point)
397 goto err;
398
399 if ((tx = BN_CTX_get(ctx)) == NULL)
400 goto err;
401 if ((ty = BN_CTX_get(ctx)) == NULL)
402 goto err;
403
404 if (!EC_POINT_set_affine_coordinates(key->group, point, x, y, ctx))
405 goto err;
406 if (!EC_POINT_get_affine_coordinates(key->group, point, tx, ty, ctx))
407 goto err;
408 /*
409 * Check if retrieved coordinates match originals: if not values are
410 * out of range.
411 */
412 if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
413 ECerror(EC_R_COORDINATES_OUT_OF_RANGE);
414 goto err;
415 }
416 if (!EC_KEY_set_public_key(key, point))
417 goto err;
418
419 if (EC_KEY_check_key(key) == 0)
420 goto err;
421
422 ok = 1;
423
424 err:
425 BN_CTX_free(ctx);
426 EC_POINT_free(point);
427 return ok;
428
429 }
430
431 const EC_GROUP *
EC_KEY_get0_group(const EC_KEY * key)432 EC_KEY_get0_group(const EC_KEY * key)
433 {
434 return key->group;
435 }
436
437 int
EC_KEY_set_group(EC_KEY * key,const EC_GROUP * group)438 EC_KEY_set_group(EC_KEY * key, const EC_GROUP * group)
439 {
440 if (key->meth->set_group != NULL &&
441 key->meth->set_group(key, group) == 0)
442 return 0;
443 EC_GROUP_free(key->group);
444 key->group = EC_GROUP_dup(group);
445 return (key->group == NULL) ? 0 : 1;
446 }
447
448 const BIGNUM *
EC_KEY_get0_private_key(const EC_KEY * key)449 EC_KEY_get0_private_key(const EC_KEY * key)
450 {
451 return key->priv_key;
452 }
453
454 int
EC_KEY_set_private_key(EC_KEY * key,const BIGNUM * priv_key)455 EC_KEY_set_private_key(EC_KEY * key, const BIGNUM * priv_key)
456 {
457 if (key->meth->set_private != NULL &&
458 key->meth->set_private(key, priv_key) == 0)
459 return 0;
460 BN_clear_free(key->priv_key);
461 key->priv_key = BN_dup(priv_key);
462 return (key->priv_key == NULL) ? 0 : 1;
463 }
464
465 const EC_POINT *
EC_KEY_get0_public_key(const EC_KEY * key)466 EC_KEY_get0_public_key(const EC_KEY * key)
467 {
468 return key->pub_key;
469 }
470
471 int
EC_KEY_set_public_key(EC_KEY * key,const EC_POINT * pub_key)472 EC_KEY_set_public_key(EC_KEY * key, const EC_POINT * pub_key)
473 {
474 if (key->meth->set_public != NULL &&
475 key->meth->set_public(key, pub_key) == 0)
476 return 0;
477 EC_POINT_free(key->pub_key);
478 key->pub_key = EC_POINT_dup(pub_key, key->group);
479 return (key->pub_key == NULL) ? 0 : 1;
480 }
481
482 unsigned int
EC_KEY_get_enc_flags(const EC_KEY * key)483 EC_KEY_get_enc_flags(const EC_KEY * key)
484 {
485 return key->enc_flag;
486 }
487
488 void
EC_KEY_set_enc_flags(EC_KEY * key,unsigned int flags)489 EC_KEY_set_enc_flags(EC_KEY * key, unsigned int flags)
490 {
491 key->enc_flag = flags;
492 }
493
494 point_conversion_form_t
EC_KEY_get_conv_form(const EC_KEY * key)495 EC_KEY_get_conv_form(const EC_KEY * key)
496 {
497 return key->conv_form;
498 }
499
500 void
EC_KEY_set_conv_form(EC_KEY * key,point_conversion_form_t cform)501 EC_KEY_set_conv_form(EC_KEY * key, point_conversion_form_t cform)
502 {
503 key->conv_form = cform;
504 if (key->group != NULL)
505 EC_GROUP_set_point_conversion_form(key->group, cform);
506 }
507
508 void *
EC_KEY_get_key_method_data(EC_KEY * key,void * (* dup_func)(void *),void (* free_func)(void *),void (* clear_free_func)(void *))509 EC_KEY_get_key_method_data(EC_KEY *key,
510 void *(*dup_func) (void *),
511 void (*free_func) (void *),
512 void (*clear_free_func) (void *))
513 {
514 void *ret;
515
516 CRYPTO_r_lock(CRYPTO_LOCK_EC);
517 ret = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
518 CRYPTO_r_unlock(CRYPTO_LOCK_EC);
519
520 return ret;
521 }
522
523 void *
EC_KEY_insert_key_method_data(EC_KEY * key,void * data,void * (* dup_func)(void *),void (* free_func)(void *),void (* clear_free_func)(void *))524 EC_KEY_insert_key_method_data(EC_KEY * key, void *data,
525 void *(*dup_func) (void *),
526 void (*free_func) (void *),
527 void (*clear_free_func) (void *))
528 {
529 EC_EXTRA_DATA *ex_data;
530
531 CRYPTO_w_lock(CRYPTO_LOCK_EC);
532 ex_data = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
533 if (ex_data == NULL)
534 EC_EX_DATA_set_data(&key->method_data, data, dup_func, free_func, clear_free_func);
535 CRYPTO_w_unlock(CRYPTO_LOCK_EC);
536
537 return ex_data;
538 }
539
540 void
EC_KEY_set_asn1_flag(EC_KEY * key,int flag)541 EC_KEY_set_asn1_flag(EC_KEY * key, int flag)
542 {
543 if (key->group != NULL)
544 EC_GROUP_set_asn1_flag(key->group, flag);
545 }
546
547 int
EC_KEY_precompute_mult(EC_KEY * key,BN_CTX * ctx)548 EC_KEY_precompute_mult(EC_KEY * key, BN_CTX * ctx)
549 {
550 if (key->group == NULL)
551 return 0;
552 return EC_GROUP_precompute_mult(key->group, ctx);
553 }
554
555 int
EC_KEY_get_flags(const EC_KEY * key)556 EC_KEY_get_flags(const EC_KEY * key)
557 {
558 return key->flags;
559 }
560
561 void
EC_KEY_set_flags(EC_KEY * key,int flags)562 EC_KEY_set_flags(EC_KEY * key, int flags)
563 {
564 key->flags |= flags;
565 }
566
567 void
EC_KEY_clear_flags(EC_KEY * key,int flags)568 EC_KEY_clear_flags(EC_KEY * key, int flags)
569 {
570 key->flags &= ~flags;
571 }
572