xref: /openbsd/lib/libcrypto/ec/ec_key.c (revision 09467b48) 
1 /* $OpenBSD: ec_key.c,v 1.24 2019/01/19 01:12:48 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 *
77 EC_KEY_new(void)
78 {
79 	return EC_KEY_new_method(NULL);
80 }
81 
82 EC_KEY *
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
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 *
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 *
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
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
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 *
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
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
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
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
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, tmp_nid, is_char_two = 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 	tmp_nid = EC_METHOD_get_field_type(EC_GROUP_method_of(key->group));
400 
401 	if (tmp_nid == NID_X9_62_characteristic_two_field)
402 		is_char_two = 1;
403 
404 	if ((tx = BN_CTX_get(ctx)) == NULL)
405 		goto err;
406 	if ((ty = BN_CTX_get(ctx)) == NULL)
407 		goto err;
408 
409 #ifndef OPENSSL_NO_EC2M
410 	if (is_char_two) {
411 		if (!EC_POINT_set_affine_coordinates_GF2m(key->group, point,
412 			x, y, ctx))
413 			goto err;
414 		if (!EC_POINT_get_affine_coordinates_GF2m(key->group, point,
415 			tx, ty, ctx))
416 			goto err;
417 	} else
418 #endif
419 	{
420 		if (!EC_POINT_set_affine_coordinates_GFp(key->group, point,
421 			x, y, ctx))
422 			goto err;
423 		if (!EC_POINT_get_affine_coordinates_GFp(key->group, point,
424 			tx, ty, ctx))
425 			goto err;
426 	}
427 	/*
428 	 * Check if retrieved coordinates match originals: if not values are
429 	 * out of range.
430 	 */
431 	if (BN_cmp(x, tx) || BN_cmp(y, ty)) {
432 		ECerror(EC_R_COORDINATES_OUT_OF_RANGE);
433 		goto err;
434 	}
435 	if (!EC_KEY_set_public_key(key, point))
436 		goto err;
437 
438 	if (EC_KEY_check_key(key) == 0)
439 		goto err;
440 
441 	ok = 1;
442 
443  err:
444 	BN_CTX_free(ctx);
445 	EC_POINT_free(point);
446 	return ok;
447 
448 }
449 
450 const EC_GROUP *
451 EC_KEY_get0_group(const EC_KEY * key)
452 {
453 	return key->group;
454 }
455 
456 int
457 EC_KEY_set_group(EC_KEY * key, const EC_GROUP * group)
458 {
459 	if (key->meth->set_group != NULL &&
460 	    key->meth->set_group(key, group) == 0)
461 		return 0;
462 	EC_GROUP_free(key->group);
463 	key->group = EC_GROUP_dup(group);
464 	return (key->group == NULL) ? 0 : 1;
465 }
466 
467 const BIGNUM *
468 EC_KEY_get0_private_key(const EC_KEY * key)
469 {
470 	return key->priv_key;
471 }
472 
473 int
474 EC_KEY_set_private_key(EC_KEY * key, const BIGNUM * priv_key)
475 {
476 	if (key->meth->set_private != NULL &&
477 	    key->meth->set_private(key, priv_key) == 0)
478 		return 0;
479 	BN_clear_free(key->priv_key);
480 	key->priv_key = BN_dup(priv_key);
481 	return (key->priv_key == NULL) ? 0 : 1;
482 }
483 
484 const EC_POINT *
485 EC_KEY_get0_public_key(const EC_KEY * key)
486 {
487 	return key->pub_key;
488 }
489 
490 int
491 EC_KEY_set_public_key(EC_KEY * key, const EC_POINT * pub_key)
492 {
493 	if (key->meth->set_public != NULL &&
494 	    key->meth->set_public(key, pub_key) == 0)
495 		return 0;
496 	EC_POINT_free(key->pub_key);
497 	key->pub_key = EC_POINT_dup(pub_key, key->group);
498 	return (key->pub_key == NULL) ? 0 : 1;
499 }
500 
501 unsigned int
502 EC_KEY_get_enc_flags(const EC_KEY * key)
503 {
504 	return key->enc_flag;
505 }
506 
507 void
508 EC_KEY_set_enc_flags(EC_KEY * key, unsigned int flags)
509 {
510 	key->enc_flag = flags;
511 }
512 
513 point_conversion_form_t
514 EC_KEY_get_conv_form(const EC_KEY * key)
515 {
516 	return key->conv_form;
517 }
518 
519 void
520 EC_KEY_set_conv_form(EC_KEY * key, point_conversion_form_t cform)
521 {
522 	key->conv_form = cform;
523 	if (key->group != NULL)
524 		EC_GROUP_set_point_conversion_form(key->group, cform);
525 }
526 
527 void *
528 EC_KEY_get_key_method_data(EC_KEY *key,
529     void *(*dup_func) (void *),
530     void (*free_func) (void *),
531     void (*clear_free_func) (void *))
532 {
533 	void *ret;
534 
535 	CRYPTO_r_lock(CRYPTO_LOCK_EC);
536 	ret = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
537 	CRYPTO_r_unlock(CRYPTO_LOCK_EC);
538 
539 	return ret;
540 }
541 
542 void *
543 EC_KEY_insert_key_method_data(EC_KEY * key, void *data,
544     void *(*dup_func) (void *),
545     void (*free_func) (void *),
546     void (*clear_free_func) (void *))
547 {
548 	EC_EXTRA_DATA *ex_data;
549 
550 	CRYPTO_w_lock(CRYPTO_LOCK_EC);
551 	ex_data = EC_EX_DATA_get_data(key->method_data, dup_func, free_func, clear_free_func);
552 	if (ex_data == NULL)
553 		EC_EX_DATA_set_data(&key->method_data, data, dup_func, free_func, clear_free_func);
554 	CRYPTO_w_unlock(CRYPTO_LOCK_EC);
555 
556 	return ex_data;
557 }
558 
559 void
560 EC_KEY_set_asn1_flag(EC_KEY * key, int flag)
561 {
562 	if (key->group != NULL)
563 		EC_GROUP_set_asn1_flag(key->group, flag);
564 }
565 
566 int
567 EC_KEY_precompute_mult(EC_KEY * key, BN_CTX * ctx)
568 {
569 	if (key->group == NULL)
570 		return 0;
571 	return EC_GROUP_precompute_mult(key->group, ctx);
572 }
573 
574 int
575 EC_KEY_get_flags(const EC_KEY * key)
576 {
577 	return key->flags;
578 }
579 
580 void
581 EC_KEY_set_flags(EC_KEY * key, int flags)
582 {
583 	key->flags |= flags;
584 }
585 
586 void
587 EC_KEY_clear_flags(EC_KEY * key, int flags)
588 {
589 	key->flags &= ~flags;
590 }
591