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[thirdparty/openssl.git] / crypto / ec / ec_lib.c
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1/*
2 * Copyright 2001-2025 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4 *
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
9 */
10
11/*
12 * EC_GROUP low level APIs are deprecated for public use, but still ok for
13 * internal use.
14 */
15#include "internal/deprecated.h"
16
17#include <string.h>
18#include <openssl/params.h>
19#include <openssl/core_names.h>
20#include <openssl/err.h>
21#include <openssl/opensslv.h>
22#include <openssl/param_build.h>
23#include "crypto/ec.h"
24#include "crypto/bn.h"
25#include "internal/nelem.h"
26#include "ec_local.h"
27
28/* functions for EC_GROUP objects */
29
30EC_GROUP *ossl_ec_group_new_ex(OSSL_LIB_CTX *libctx, const char *propq,
31 const EC_METHOD *meth)
32{
33 EC_GROUP *ret;
34
35 if (meth == NULL) {
36 ERR_raise(ERR_LIB_EC, EC_R_SLOT_FULL);
37 return NULL;
38 }
39 if (meth->group_init == 0) {
40 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
41 return NULL;
42 }
43
44 ret = OPENSSL_zalloc(sizeof(*ret));
45 if (ret == NULL)
46 return NULL;
47
48 ret->libctx = libctx;
49 if (propq != NULL) {
50 ret->propq = OPENSSL_strdup(propq);
51 if (ret->propq == NULL)
52 goto err;
53 }
54 ret->meth = meth;
55 if ((ret->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
56 ret->order = BN_new();
57 if (ret->order == NULL)
58 goto err;
59 ret->cofactor = BN_new();
60 if (ret->cofactor == NULL)
61 goto err;
62 }
63 ret->asn1_flag = OPENSSL_EC_EXPLICIT_CURVE;
64 ret->asn1_form = POINT_CONVERSION_UNCOMPRESSED;
65 if (!meth->group_init(ret))
66 goto err;
67 return ret;
68
69 err:
70 BN_free(ret->order);
71 BN_free(ret->cofactor);
72 OPENSSL_free(ret->propq);
73 OPENSSL_free(ret);
74 return NULL;
75}
76
77#ifndef OPENSSL_NO_DEPRECATED_3_0
78# ifndef FIPS_MODULE
79EC_GROUP *EC_GROUP_new(const EC_METHOD *meth)
80{
81 return ossl_ec_group_new_ex(NULL, NULL, meth);
82}
83# endif
84#endif
85
86void EC_pre_comp_free(EC_GROUP *group)
87{
88 switch (group->pre_comp_type) {
89 case PCT_none:
90 break;
91 case PCT_nistz256:
92#ifdef ECP_NISTZ256_ASM
93 EC_nistz256_pre_comp_free(group->pre_comp.nistz256);
94#endif
95 break;
96#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
97 case PCT_nistp224:
98 EC_nistp224_pre_comp_free(group->pre_comp.nistp224);
99 break;
100 case PCT_nistp256:
101 EC_nistp256_pre_comp_free(group->pre_comp.nistp256);
102 break;
103 case PCT_nistp384:
104 ossl_ec_nistp384_pre_comp_free(group->pre_comp.nistp384);
105 break;
106 case PCT_nistp521:
107 EC_nistp521_pre_comp_free(group->pre_comp.nistp521);
108 break;
109#else
110 case PCT_nistp224:
111 case PCT_nistp256:
112 case PCT_nistp384:
113 case PCT_nistp521:
114 break;
115#endif
116 case PCT_ec:
117 EC_ec_pre_comp_free(group->pre_comp.ec);
118 break;
119 }
120 group->pre_comp.ec = NULL;
121}
122
123void EC_GROUP_free(EC_GROUP *group)
124{
125 if (!group)
126 return;
127
128 if (group->meth->group_finish != 0)
129 group->meth->group_finish(group);
130
131 EC_pre_comp_free(group);
132 BN_MONT_CTX_free(group->mont_data);
133 EC_POINT_free(group->generator);
134 BN_free(group->order);
135 BN_free(group->cofactor);
136 OPENSSL_free(group->seed);
137 OPENSSL_free(group->propq);
138 OPENSSL_free(group);
139}
140
141#ifndef OPENSSL_NO_DEPRECATED_3_0
142void EC_GROUP_clear_free(EC_GROUP *group)
143{
144 if (!group)
145 return;
146
147 if (group->meth->group_clear_finish != 0)
148 group->meth->group_clear_finish(group);
149 else if (group->meth->group_finish != 0)
150 group->meth->group_finish(group);
151
152 EC_pre_comp_free(group);
153 BN_MONT_CTX_free(group->mont_data);
154 EC_POINT_clear_free(group->generator);
155 BN_clear_free(group->order);
156 BN_clear_free(group->cofactor);
157 OPENSSL_clear_free(group->seed, group->seed_len);
158 OPENSSL_clear_free(group, sizeof(*group));
159}
160#endif
161
162int EC_GROUP_copy(EC_GROUP *dest, const EC_GROUP *src)
163{
164 if (dest->meth->group_copy == 0) {
165 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
166 return 0;
167 }
168 if (dest->meth != src->meth) {
169 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
170 return 0;
171 }
172 if (dest == src)
173 return 1;
174
175 dest->libctx = src->libctx;
176 dest->curve_name = src->curve_name;
177
178 /* Copy precomputed */
179 dest->pre_comp_type = src->pre_comp_type;
180 switch (src->pre_comp_type) {
181 case PCT_none:
182 dest->pre_comp.ec = NULL;
183 break;
184 case PCT_nistz256:
185#ifdef ECP_NISTZ256_ASM
186 dest->pre_comp.nistz256 = EC_nistz256_pre_comp_dup(src->pre_comp.nistz256);
187#endif
188 break;
189#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
190 case PCT_nistp224:
191 dest->pre_comp.nistp224 = EC_nistp224_pre_comp_dup(src->pre_comp.nistp224);
192 break;
193 case PCT_nistp256:
194 dest->pre_comp.nistp256 = EC_nistp256_pre_comp_dup(src->pre_comp.nistp256);
195 break;
196 case PCT_nistp384:
197 dest->pre_comp.nistp384 = ossl_ec_nistp384_pre_comp_dup(src->pre_comp.nistp384);
198 break;
199 case PCT_nistp521:
200 dest->pre_comp.nistp521 = EC_nistp521_pre_comp_dup(src->pre_comp.nistp521);
201 break;
202#else
203 case PCT_nistp224:
204 case PCT_nistp256:
205 case PCT_nistp384:
206 case PCT_nistp521:
207 break;
208#endif
209 case PCT_ec:
210 dest->pre_comp.ec = EC_ec_pre_comp_dup(src->pre_comp.ec);
211 break;
212 }
213
214 if (src->mont_data != NULL) {
215 if (dest->mont_data == NULL) {
216 dest->mont_data = BN_MONT_CTX_new();
217 if (dest->mont_data == NULL)
218 return 0;
219 }
220 if (!BN_MONT_CTX_copy(dest->mont_data, src->mont_data))
221 return 0;
222 } else {
223 /* src->generator == NULL */
224 BN_MONT_CTX_free(dest->mont_data);
225 dest->mont_data = NULL;
226 }
227
228 if (src->generator != NULL) {
229 if (dest->generator == NULL) {
230 dest->generator = EC_POINT_new(dest);
231 if (dest->generator == NULL)
232 return 0;
233 }
234 if (!EC_POINT_copy(dest->generator, src->generator))
235 return 0;
236 } else {
237 /* src->generator == NULL */
238 EC_POINT_clear_free(dest->generator);
239 dest->generator = NULL;
240 }
241
242 if ((src->meth->flags & EC_FLAGS_CUSTOM_CURVE) == 0) {
243 if (!BN_copy(dest->order, src->order))
244 return 0;
245 if (!BN_copy(dest->cofactor, src->cofactor))
246 return 0;
247 }
248
249 dest->asn1_flag = src->asn1_flag;
250 dest->asn1_form = src->asn1_form;
251 dest->decoded_from_explicit_params = src->decoded_from_explicit_params;
252
253 if (src->seed) {
254 OPENSSL_free(dest->seed);
255 if ((dest->seed = OPENSSL_malloc(src->seed_len)) == NULL)
256 return 0;
257 if (!memcpy(dest->seed, src->seed, src->seed_len))
258 return 0;
259 dest->seed_len = src->seed_len;
260 } else {
261 OPENSSL_free(dest->seed);
262 dest->seed = NULL;
263 dest->seed_len = 0;
264 }
265
266 return dest->meth->group_copy(dest, src);
267}
268
269EC_GROUP *EC_GROUP_dup(const EC_GROUP *a)
270{
271 EC_GROUP *t = NULL;
272 int ok = 0;
273
274 if (a == NULL)
275 return NULL;
276
277 if ((t = ossl_ec_group_new_ex(a->libctx, a->propq, a->meth)) == NULL)
278 return NULL;
279 if (!EC_GROUP_copy(t, a))
280 goto err;
281
282 ok = 1;
283
284 err:
285 if (!ok) {
286 EC_GROUP_free(t);
287 return NULL;
288 }
289 return t;
290}
291
292#ifndef OPENSSL_NO_DEPRECATED_3_0
293const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group)
294{
295 return group->meth;
296}
297
298int EC_METHOD_get_field_type(const EC_METHOD *meth)
299{
300 return meth->field_type;
301}
302#endif
303
304static int ec_precompute_mont_data(EC_GROUP *);
305
306/*-
307 * Try computing cofactor from the generator order (n) and field cardinality (q).
308 * This works for all curves of cryptographic interest.
309 *
310 * Hasse thm: q + 1 - 2*sqrt(q) <= n*h <= q + 1 + 2*sqrt(q)
311 * h_min = (q + 1 - 2*sqrt(q))/n
312 * h_max = (q + 1 + 2*sqrt(q))/n
313 * h_max - h_min = 4*sqrt(q)/n
314 * So if n > 4*sqrt(q) holds, there is only one possible value for h:
315 * h = \lfloor (h_min + h_max)/2 \rceil = \lfloor (q + 1)/n \rceil
316 *
317 * Otherwise, zero cofactor and return success.
318 */
319static int ec_guess_cofactor(EC_GROUP *group) {
320 int ret = 0;
321 BN_CTX *ctx = NULL;
322 BIGNUM *q = NULL;
323
324 /*-
325 * If the cofactor is too large, we cannot guess it.
326 * The RHS of below is a strict overestimate of lg(4 * sqrt(q))
327 */
328 if (BN_num_bits(group->order) <= (BN_num_bits(group->field) + 1) / 2 + 3) {
329 /* default to 0 */
330 BN_zero(group->cofactor);
331 /* return success */
332 return 1;
333 }
334
335 if ((ctx = BN_CTX_new_ex(group->libctx)) == NULL)
336 return 0;
337
338 BN_CTX_start(ctx);
339 if ((q = BN_CTX_get(ctx)) == NULL)
340 goto err;
341
342 /* set q = 2**m for binary fields; q = p otherwise */
343 if (group->meth->field_type == NID_X9_62_characteristic_two_field) {
344 BN_zero(q);
345 if (!BN_set_bit(q, BN_num_bits(group->field) - 1))
346 goto err;
347 } else {
348 if (!BN_copy(q, group->field))
349 goto err;
350 }
351
352 /* compute h = \lfloor (q + 1)/n \rceil = \lfloor (q + 1 + n/2)/n \rfloor */
353 if (!BN_rshift1(group->cofactor, group->order) /* n/2 */
354 || !BN_add(group->cofactor, group->cofactor, q) /* q + n/2 */
355 /* q + 1 + n/2 */
356 || !BN_add(group->cofactor, group->cofactor, BN_value_one())
357 /* (q + 1 + n/2)/n */
358 || !BN_div(group->cofactor, NULL, group->cofactor, group->order, ctx))
359 goto err;
360 ret = 1;
361 err:
362 BN_CTX_end(ctx);
363 BN_CTX_free(ctx);
364 return ret;
365}
366
367int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
368 const BIGNUM *order, const BIGNUM *cofactor)
369{
370 if (generator == NULL) {
371 ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
372 return 0;
373 }
374
375 /* require group->field >= 1 */
376 if (group->field == NULL || BN_is_zero(group->field)
377 || BN_is_negative(group->field)) {
378 ERR_raise(ERR_LIB_EC, EC_R_INVALID_FIELD);
379 return 0;
380 }
381
382 /*-
383 * - require order >= 1
384 * - enforce upper bound due to Hasse thm: order can be no more than one bit
385 * longer than field cardinality
386 */
387 if (order == NULL || BN_is_zero(order) || BN_is_negative(order)
388 || BN_num_bits(order) > BN_num_bits(group->field) + 1) {
389 ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER);
390 return 0;
391 }
392
393 /*-
394 * Unfortunately the cofactor is an optional field in many standards.
395 * Internally, the lib uses 0 cofactor as a marker for "unknown cofactor".
396 * So accept cofactor == NULL or cofactor >= 0.
397 */
398 if (cofactor != NULL && BN_is_negative(cofactor)) {
399 ERR_raise(ERR_LIB_EC, EC_R_UNKNOWN_COFACTOR);
400 return 0;
401 }
402
403 if (group->generator == NULL) {
404 group->generator = EC_POINT_new(group);
405 if (group->generator == NULL)
406 return 0;
407 }
408 if (!EC_POINT_copy(group->generator, generator))
409 return 0;
410
411 if (!BN_copy(group->order, order))
412 return 0;
413
414 /* Either take the provided positive cofactor, or try to compute it */
415 if (cofactor != NULL && !BN_is_zero(cofactor)) {
416 if (!BN_copy(group->cofactor, cofactor))
417 return 0;
418 } else if (!ec_guess_cofactor(group)) {
419 BN_zero(group->cofactor);
420 return 0;
421 }
422
423 /*
424 * Some groups have an order with
425 * factors of two, which makes the Montgomery setup fail.
426 * |group->mont_data| will be NULL in this case.
427 */
428 if (BN_is_odd(group->order)) {
429 return ec_precompute_mont_data(group);
430 }
431
432 BN_MONT_CTX_free(group->mont_data);
433 group->mont_data = NULL;
434 return 1;
435}
436
437const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group)
438{
439 return group->generator;
440}
441
442BN_MONT_CTX *EC_GROUP_get_mont_data(const EC_GROUP *group)
443{
444 return group->mont_data;
445}
446
447int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx)
448{
449 if (group->order == NULL)
450 return 0;
451 if (!BN_copy(order, group->order))
452 return 0;
453
454 return !BN_is_zero(order);
455}
456
457const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group)
458{
459 return group->order;
460}
461
462int EC_GROUP_order_bits(const EC_GROUP *group)
463{
464 return group->meth->group_order_bits(group);
465}
466
467int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor,
468 BN_CTX *ctx)
469{
470
471 if (group->cofactor == NULL)
472 return 0;
473 if (!BN_copy(cofactor, group->cofactor))
474 return 0;
475
476 return !BN_is_zero(group->cofactor);
477}
478
479const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group)
480{
481 return group->cofactor;
482}
483
484void EC_GROUP_set_curve_name(EC_GROUP *group, int nid)
485{
486 group->curve_name = nid;
487 group->asn1_flag =
488 (nid != NID_undef)
489 ? OPENSSL_EC_NAMED_CURVE
490 : OPENSSL_EC_EXPLICIT_CURVE;
491}
492
493int EC_GROUP_get_curve_name(const EC_GROUP *group)
494{
495 return group->curve_name;
496}
497
498const BIGNUM *EC_GROUP_get0_field(const EC_GROUP *group)
499{
500 return group->field;
501}
502
503int EC_GROUP_get_field_type(const EC_GROUP *group)
504{
505 return group->meth->field_type;
506}
507
508void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag)
509{
510 group->asn1_flag = flag;
511}
512
513int EC_GROUP_get_asn1_flag(const EC_GROUP *group)
514{
515 return group->asn1_flag;
516}
517
518void EC_GROUP_set_point_conversion_form(EC_GROUP *group,
519 point_conversion_form_t form)
520{
521 group->asn1_form = form;
522}
523
524point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP
525 *group)
526{
527 return group->asn1_form;
528}
529
530size_t EC_GROUP_set_seed(EC_GROUP *group, const unsigned char *p, size_t len)
531{
532 OPENSSL_free(group->seed);
533 group->seed = NULL;
534 group->seed_len = 0;
535
536 if (!len || !p)
537 return 1;
538
539 if ((group->seed = OPENSSL_malloc(len)) == NULL)
540 return 0;
541 memcpy(group->seed, p, len);
542 group->seed_len = len;
543
544 return len;
545}
546
547unsigned char *EC_GROUP_get0_seed(const EC_GROUP *group)
548{
549 return group->seed;
550}
551
552size_t EC_GROUP_get_seed_len(const EC_GROUP *group)
553{
554 return group->seed_len;
555}
556
557int EC_GROUP_set_curve(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
558 const BIGNUM *b, BN_CTX *ctx)
559{
560 if (group->meth->group_set_curve == 0) {
561 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
562 return 0;
563 }
564 return group->meth->group_set_curve(group, p, a, b, ctx);
565}
566
567int EC_GROUP_get_curve(const EC_GROUP *group, BIGNUM *p, BIGNUM *a, BIGNUM *b,
568 BN_CTX *ctx)
569{
570 if (group->meth->group_get_curve == NULL) {
571 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
572 return 0;
573 }
574 return group->meth->group_get_curve(group, p, a, b, ctx);
575}
576
577#ifndef OPENSSL_NO_DEPRECATED_3_0
578int EC_GROUP_set_curve_GFp(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
579 const BIGNUM *b, BN_CTX *ctx)
580{
581 return EC_GROUP_set_curve(group, p, a, b, ctx);
582}
583
584int EC_GROUP_get_curve_GFp(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
585 BIGNUM *b, BN_CTX *ctx)
586{
587 return EC_GROUP_get_curve(group, p, a, b, ctx);
588}
589
590# ifndef OPENSSL_NO_EC2M
591int EC_GROUP_set_curve_GF2m(EC_GROUP *group, const BIGNUM *p, const BIGNUM *a,
592 const BIGNUM *b, BN_CTX *ctx)
593{
594 return EC_GROUP_set_curve(group, p, a, b, ctx);
595}
596
597int EC_GROUP_get_curve_GF2m(const EC_GROUP *group, BIGNUM *p, BIGNUM *a,
598 BIGNUM *b, BN_CTX *ctx)
599{
600 return EC_GROUP_get_curve(group, p, a, b, ctx);
601}
602# endif
603#endif
604
605int EC_GROUP_get_degree(const EC_GROUP *group)
606{
607 if (group->meth->group_get_degree == 0) {
608 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
609 return 0;
610 }
611 return group->meth->group_get_degree(group);
612}
613
614int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx)
615{
616 if (group->meth->group_check_discriminant == 0) {
617 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
618 return 0;
619 }
620 return group->meth->group_check_discriminant(group, ctx);
621}
622
623int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx)
624{
625 int r = 0;
626 BIGNUM *a1, *a2, *a3, *b1, *b2, *b3;
627#ifndef FIPS_MODULE
628 BN_CTX *ctx_new = NULL;
629#endif
630
631 /* compare the field types */
632 if (EC_GROUP_get_field_type(a) != EC_GROUP_get_field_type(b))
633 return 1;
634 /* compare the curve name (if present in both) */
635 if (EC_GROUP_get_curve_name(a) && EC_GROUP_get_curve_name(b) &&
636 EC_GROUP_get_curve_name(a) != EC_GROUP_get_curve_name(b))
637 return 1;
638 if (a->meth->flags & EC_FLAGS_CUSTOM_CURVE)
639 return 0;
640
641#ifndef FIPS_MODULE
642 if (ctx == NULL)
643 ctx_new = ctx = BN_CTX_new();
644#endif
645 if (ctx == NULL)
646 return -1;
647
648 BN_CTX_start(ctx);
649 a1 = BN_CTX_get(ctx);
650 a2 = BN_CTX_get(ctx);
651 a3 = BN_CTX_get(ctx);
652 b1 = BN_CTX_get(ctx);
653 b2 = BN_CTX_get(ctx);
654 b3 = BN_CTX_get(ctx);
655 if (b3 == NULL) {
656 BN_CTX_end(ctx);
657#ifndef FIPS_MODULE
658 BN_CTX_free(ctx_new);
659#endif
660 return -1;
661 }
662
663 /*
664 * XXX This approach assumes that the external representation of curves
665 * over the same field type is the same.
666 */
667 if (!a->meth->group_get_curve(a, a1, a2, a3, ctx) ||
668 !b->meth->group_get_curve(b, b1, b2, b3, ctx))
669 r = 1;
670
671 /* return 1 if the curve parameters are different */
672 if (r || BN_cmp(a1, b1) != 0 || BN_cmp(a2, b2) != 0 || BN_cmp(a3, b3) != 0)
673 r = 1;
674
675 /* XXX EC_POINT_cmp() assumes that the methods are equal */
676 /* return 1 if the generators are different */
677 if (r || EC_POINT_cmp(a, EC_GROUP_get0_generator(a),
678 EC_GROUP_get0_generator(b), ctx) != 0)
679 r = 1;
680
681 if (!r) {
682 const BIGNUM *ao, *bo, *ac, *bc;
683 /* compare the orders */
684 ao = EC_GROUP_get0_order(a);
685 bo = EC_GROUP_get0_order(b);
686 if (ao == NULL || bo == NULL) {
687 /* return an error if either order is NULL */
688 r = -1;
689 goto end;
690 }
691 if (BN_cmp(ao, bo) != 0) {
692 /* return 1 if orders are different */
693 r = 1;
694 goto end;
695 }
696 /*
697 * It gets here if the curve parameters and generator matched.
698 * Now check the optional cofactors (if both are present).
699 */
700 ac = EC_GROUP_get0_cofactor(a);
701 bc = EC_GROUP_get0_cofactor(b);
702 /* Returns 1 (mismatch) if both cofactors are specified and different */
703 if (!BN_is_zero(ac) && !BN_is_zero(bc) && BN_cmp(ac, bc) != 0)
704 r = 1;
705 /* Returns 0 if the parameters matched */
706 }
707end:
708 BN_CTX_end(ctx);
709#ifndef FIPS_MODULE
710 BN_CTX_free(ctx_new);
711#endif
712 return r;
713}
714
715/* functions for EC_POINT objects */
716
717EC_POINT *EC_POINT_new(const EC_GROUP *group)
718{
719 EC_POINT *ret;
720
721 if (group == NULL) {
722 ERR_raise(ERR_LIB_EC, ERR_R_PASSED_NULL_PARAMETER);
723 return NULL;
724 }
725 if (group->meth->point_init == NULL) {
726 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
727 return NULL;
728 }
729
730 ret = OPENSSL_zalloc(sizeof(*ret));
731 if (ret == NULL)
732 return NULL;
733
734 ret->meth = group->meth;
735 ret->curve_name = group->curve_name;
736
737 if (!ret->meth->point_init(ret)) {
738 OPENSSL_free(ret);
739 return NULL;
740 }
741
742 return ret;
743}
744
745void EC_POINT_free(EC_POINT *point)
746{
747 if (point == NULL)
748 return;
749
750#ifdef OPENSSL_PEDANTIC_ZEROIZATION
751 EC_POINT_clear_free(point);
752#else
753 if (point->meth->point_finish != 0)
754 point->meth->point_finish(point);
755 OPENSSL_free(point);
756#endif
757}
758
759void EC_POINT_clear_free(EC_POINT *point)
760{
761 if (point == NULL)
762 return;
763
764 if (point->meth->point_clear_finish != 0)
765 point->meth->point_clear_finish(point);
766 else if (point->meth->point_finish != 0)
767 point->meth->point_finish(point);
768 OPENSSL_clear_free(point, sizeof(*point));
769}
770
771int EC_POINT_copy(EC_POINT *dest, const EC_POINT *src)
772{
773 if (dest->meth->point_copy == 0) {
774 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
775 return 0;
776 }
777 if (dest->meth != src->meth
778 || (dest->curve_name != src->curve_name
779 && dest->curve_name != 0
780 && src->curve_name != 0)) {
781 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
782 return 0;
783 }
784 if (dest == src)
785 return 1;
786 return dest->meth->point_copy(dest, src);
787}
788
789EC_POINT *EC_POINT_dup(const EC_POINT *a, const EC_GROUP *group)
790{
791 EC_POINT *t;
792 int r;
793
794 if (a == NULL)
795 return NULL;
796
797 t = EC_POINT_new(group);
798 if (t == NULL)
799 return NULL;
800 r = EC_POINT_copy(t, a);
801 if (!r) {
802 EC_POINT_free(t);
803 return NULL;
804 }
805 return t;
806}
807
808#ifndef OPENSSL_NO_DEPRECATED_3_0
809const EC_METHOD *EC_POINT_method_of(const EC_POINT *point)
810{
811 return point->meth;
812}
813#endif
814
815int EC_POINT_set_to_infinity(const EC_GROUP *group, EC_POINT *point)
816{
817 if (group->meth->point_set_to_infinity == 0) {
818 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
819 return 0;
820 }
821 if (group->meth != point->meth) {
822 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
823 return 0;
824 }
825 return group->meth->point_set_to_infinity(group, point);
826}
827
828#ifndef OPENSSL_NO_DEPRECATED_3_0
829int EC_POINT_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
830 EC_POINT *point, const BIGNUM *x,
831 const BIGNUM *y, const BIGNUM *z,
832 BN_CTX *ctx)
833{
834 if (group->meth->field_type != NID_X9_62_prime_field) {
835 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
836 return 0;
837 }
838 if (!ec_point_is_compat(point, group)) {
839 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
840 return 0;
841 }
842 return ossl_ec_GFp_simple_set_Jprojective_coordinates_GFp(group, point,
843 x, y, z, ctx);
844}
845
846int EC_POINT_get_Jprojective_coordinates_GFp(const EC_GROUP *group,
847 const EC_POINT *point, BIGNUM *x,
848 BIGNUM *y, BIGNUM *z,
849 BN_CTX *ctx)
850{
851 if (group->meth->field_type != NID_X9_62_prime_field) {
852 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
853 return 0;
854 }
855 if (!ec_point_is_compat(point, group)) {
856 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
857 return 0;
858 }
859 return ossl_ec_GFp_simple_get_Jprojective_coordinates_GFp(group, point,
860 x, y, z, ctx);
861}
862#endif
863
864int EC_POINT_set_affine_coordinates(const EC_GROUP *group, EC_POINT *point,
865 const BIGNUM *x, const BIGNUM *y,
866 BN_CTX *ctx)
867{
868 if (group->meth->point_set_affine_coordinates == NULL) {
869 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
870 return 0;
871 }
872 if (!ec_point_is_compat(point, group)) {
873 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
874 return 0;
875 }
876 if (!group->meth->point_set_affine_coordinates(group, point, x, y, ctx))
877 return 0;
878
879 if (EC_POINT_is_on_curve(group, point, ctx) <= 0) {
880 ERR_raise(ERR_LIB_EC, EC_R_POINT_IS_NOT_ON_CURVE);
881 return 0;
882 }
883 return 1;
884}
885
886#ifndef OPENSSL_NO_DEPRECATED_3_0
887int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group,
888 EC_POINT *point, const BIGNUM *x,
889 const BIGNUM *y, BN_CTX *ctx)
890{
891 return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
892}
893
894# ifndef OPENSSL_NO_EC2M
895int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group,
896 EC_POINT *point, const BIGNUM *x,
897 const BIGNUM *y, BN_CTX *ctx)
898{
899 return EC_POINT_set_affine_coordinates(group, point, x, y, ctx);
900}
901# endif
902#endif
903
904int EC_POINT_get_affine_coordinates(const EC_GROUP *group,
905 const EC_POINT *point, BIGNUM *x, BIGNUM *y,
906 BN_CTX *ctx)
907{
908 if (group->meth->point_get_affine_coordinates == NULL) {
909 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
910 return 0;
911 }
912 if (!ec_point_is_compat(point, group)) {
913 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
914 return 0;
915 }
916 if (EC_POINT_is_at_infinity(group, point)) {
917 ERR_raise(ERR_LIB_EC, EC_R_POINT_AT_INFINITY);
918 return 0;
919 }
920 return group->meth->point_get_affine_coordinates(group, point, x, y, ctx);
921}
922
923#ifndef OPENSSL_NO_DEPRECATED_3_0
924int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
925 const EC_POINT *point, BIGNUM *x,
926 BIGNUM *y, BN_CTX *ctx)
927{
928 return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
929}
930
931# ifndef OPENSSL_NO_EC2M
932int EC_POINT_get_affine_coordinates_GF2m(const EC_GROUP *group,
933 const EC_POINT *point, BIGNUM *x,
934 BIGNUM *y, BN_CTX *ctx)
935{
936 return EC_POINT_get_affine_coordinates(group, point, x, y, ctx);
937}
938# endif
939#endif
940
941int EC_POINT_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
942 const EC_POINT *b, BN_CTX *ctx)
943{
944 if (group->meth->add == 0) {
945 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
946 return 0;
947 }
948 if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)
949 || !ec_point_is_compat(b, group)) {
950 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
951 return 0;
952 }
953 return group->meth->add(group, r, a, b, ctx);
954}
955
956int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
957 BN_CTX *ctx)
958{
959 if (group->meth->dbl == 0) {
960 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
961 return 0;
962 }
963 if (!ec_point_is_compat(r, group) || !ec_point_is_compat(a, group)) {
964 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
965 return 0;
966 }
967 return group->meth->dbl(group, r, a, ctx);
968}
969
970int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a, BN_CTX *ctx)
971{
972 if (group->meth->invert == 0) {
973 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
974 return 0;
975 }
976 if (!ec_point_is_compat(a, group)) {
977 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
978 return 0;
979 }
980 return group->meth->invert(group, a, ctx);
981}
982
983int EC_POINT_is_at_infinity(const EC_GROUP *group, const EC_POINT *point)
984{
985 if (group->meth->is_at_infinity == 0) {
986 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
987 return 0;
988 }
989 if (!ec_point_is_compat(point, group)) {
990 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
991 return 0;
992 }
993 return group->meth->is_at_infinity(group, point);
994}
995
996/*
997 * Check whether an EC_POINT is on the curve or not. Note that the return
998 * value for this function should NOT be treated as a boolean. Return values:
999 * 1: The point is on the curve
1000 * 0: The point is not on the curve
1001 * -1: An error occurred
1002 */
1003int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point,
1004 BN_CTX *ctx)
1005{
1006 if (group->meth->is_on_curve == 0) {
1007 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1008 return 0;
1009 }
1010 if (!ec_point_is_compat(point, group)) {
1011 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1012 return 0;
1013 }
1014 return group->meth->is_on_curve(group, point, ctx);
1015}
1016
1017int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b,
1018 BN_CTX *ctx)
1019{
1020 if (group->meth->point_cmp == 0) {
1021 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1022 return -1;
1023 }
1024 if (!ec_point_is_compat(a, group) || !ec_point_is_compat(b, group)) {
1025 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1026 return -1;
1027 }
1028 return group->meth->point_cmp(group, a, b, ctx);
1029}
1030
1031#ifndef OPENSSL_NO_DEPRECATED_3_0
1032int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx)
1033{
1034 if (group->meth->make_affine == 0) {
1035 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1036 return 0;
1037 }
1038 if (!ec_point_is_compat(point, group)) {
1039 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1040 return 0;
1041 }
1042 return group->meth->make_affine(group, point, ctx);
1043}
1044
1045int EC_POINTs_make_affine(const EC_GROUP *group, size_t num,
1046 EC_POINT *points[], BN_CTX *ctx)
1047{
1048 size_t i;
1049
1050 if (group->meth->points_make_affine == 0) {
1051 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1052 return 0;
1053 }
1054 for (i = 0; i < num; i++) {
1055 if (!ec_point_is_compat(points[i], group)) {
1056 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1057 return 0;
1058 }
1059 }
1060 return group->meth->points_make_affine(group, num, points, ctx);
1061}
1062#endif
1063
1064/*
1065 * Functions for point multiplication. If group->meth->mul is 0, we use the
1066 * wNAF-based implementations in ec_mult.c; otherwise we dispatch through
1067 * methods.
1068 */
1069
1070#ifndef OPENSSL_NO_DEPRECATED_3_0
1071int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
1072 size_t num, const EC_POINT *points[],
1073 const BIGNUM *scalars[], BN_CTX *ctx)
1074{
1075 int ret = 0;
1076 size_t i = 0;
1077#ifndef FIPS_MODULE
1078 BN_CTX *new_ctx = NULL;
1079#endif
1080
1081 if (!ec_point_is_compat(r, group)) {
1082 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1083 return 0;
1084 }
1085
1086 if (scalar == NULL && num == 0)
1087 return EC_POINT_set_to_infinity(group, r);
1088
1089 for (i = 0; i < num; i++) {
1090 if (!ec_point_is_compat(points[i], group)) {
1091 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1092 return 0;
1093 }
1094 }
1095
1096#ifndef FIPS_MODULE
1097 if (ctx == NULL)
1098 ctx = new_ctx = BN_CTX_secure_new();
1099#endif
1100 if (ctx == NULL) {
1101 ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
1102 return 0;
1103 }
1104
1105 if (group->meth->mul != NULL)
1106 ret = group->meth->mul(group, r, scalar, num, points, scalars, ctx);
1107 else
1108 /* use default */
1109 ret = ossl_ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
1110
1111#ifndef FIPS_MODULE
1112 BN_CTX_free(new_ctx);
1113#endif
1114 return ret;
1115}
1116#endif
1117
1118int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
1119 const EC_POINT *point, const BIGNUM *p_scalar, BN_CTX *ctx)
1120{
1121 int ret = 0;
1122 size_t num;
1123#ifndef FIPS_MODULE
1124 BN_CTX *new_ctx = NULL;
1125#endif
1126
1127 if (!ec_point_is_compat(r, group)
1128 || (point != NULL && !ec_point_is_compat(point, group))) {
1129 ERR_raise(ERR_LIB_EC, EC_R_INCOMPATIBLE_OBJECTS);
1130 return 0;
1131 }
1132
1133 if (g_scalar == NULL && p_scalar == NULL)
1134 return EC_POINT_set_to_infinity(group, r);
1135
1136#ifndef FIPS_MODULE
1137 if (ctx == NULL)
1138 ctx = new_ctx = BN_CTX_secure_new();
1139#endif
1140 if (ctx == NULL) {
1141 ERR_raise(ERR_LIB_EC, ERR_R_INTERNAL_ERROR);
1142 return 0;
1143 }
1144
1145 num = (point != NULL && p_scalar != NULL) ? 1 : 0;
1146 if (group->meth->mul != NULL)
1147 ret = group->meth->mul(group, r, g_scalar, num, &point, &p_scalar, ctx);
1148 else
1149 /* use default */
1150 ret = ossl_ec_wNAF_mul(group, r, g_scalar, num, &point, &p_scalar, ctx);
1151
1152#ifndef FIPS_MODULE
1153 BN_CTX_free(new_ctx);
1154#endif
1155 return ret;
1156}
1157
1158#ifndef OPENSSL_NO_DEPRECATED_3_0
1159int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
1160{
1161 if (group->meth->mul == 0)
1162 /* use default */
1163 return ossl_ec_wNAF_precompute_mult(group, ctx);
1164
1165 if (group->meth->precompute_mult != 0)
1166 return group->meth->precompute_mult(group, ctx);
1167 else
1168 return 1; /* nothing to do, so report success */
1169}
1170
1171int EC_GROUP_have_precompute_mult(const EC_GROUP *group)
1172{
1173 if (group->meth->mul == 0)
1174 /* use default */
1175 return ossl_ec_wNAF_have_precompute_mult(group);
1176
1177 if (group->meth->have_precompute_mult != 0)
1178 return group->meth->have_precompute_mult(group);
1179 else
1180 return 0; /* cannot tell whether precomputation has
1181 * been performed */
1182}
1183#endif
1184
1185/*
1186 * ec_precompute_mont_data sets |group->mont_data| from |group->order| and
1187 * returns one on success. On error it returns zero.
1188 */
1189static int ec_precompute_mont_data(EC_GROUP *group)
1190{
1191 BN_CTX *ctx = BN_CTX_new_ex(group->libctx);
1192 int ret = 0;
1193
1194 BN_MONT_CTX_free(group->mont_data);
1195 group->mont_data = NULL;
1196
1197 if (ctx == NULL)
1198 goto err;
1199
1200 group->mont_data = BN_MONT_CTX_new();
1201 if (group->mont_data == NULL)
1202 goto err;
1203
1204 if (!BN_MONT_CTX_set(group->mont_data, group->order, ctx)) {
1205 BN_MONT_CTX_free(group->mont_data);
1206 group->mont_data = NULL;
1207 goto err;
1208 }
1209
1210 ret = 1;
1211
1212 err:
1213
1214 BN_CTX_free(ctx);
1215 return ret;
1216}
1217
1218#ifndef FIPS_MODULE
1219int EC_KEY_set_ex_data(EC_KEY *key, int idx, void *arg)
1220{
1221 return CRYPTO_set_ex_data(&key->ex_data, idx, arg);
1222}
1223
1224void *EC_KEY_get_ex_data(const EC_KEY *key, int idx)
1225{
1226 return CRYPTO_get_ex_data(&key->ex_data, idx);
1227}
1228#endif
1229
1230int ossl_ec_group_simple_order_bits(const EC_GROUP *group)
1231{
1232 if (group->order == NULL)
1233 return 0;
1234 return BN_num_bits(group->order);
1235}
1236
1237static int ec_field_inverse_mod_ord(const EC_GROUP *group, BIGNUM *r,
1238 const BIGNUM *x, BN_CTX *ctx)
1239{
1240 BIGNUM *e = NULL;
1241 int ret = 0;
1242#ifndef FIPS_MODULE
1243 BN_CTX *new_ctx = NULL;
1244#endif
1245
1246 if (group->mont_data == NULL)
1247 return 0;
1248
1249#ifndef FIPS_MODULE
1250 if (ctx == NULL)
1251 ctx = new_ctx = BN_CTX_secure_new();
1252#endif
1253 if (ctx == NULL)
1254 return 0;
1255
1256 BN_CTX_start(ctx);
1257 if ((e = BN_CTX_get(ctx)) == NULL)
1258 goto err;
1259
1260 /*-
1261 * We want inverse in constant time, therefore we utilize the fact
1262 * order must be prime and use Fermats Little Theorem instead.
1263 */
1264 if (!BN_set_word(e, 2))
1265 goto err;
1266 if (!BN_sub(e, group->order, e))
1267 goto err;
1268 /*-
1269 * Although the exponent is public we want the result to be
1270 * fixed top.
1271 */
1272 if (!bn_mod_exp_mont_fixed_top(r, x, e, group->order, ctx, group->mont_data))
1273 goto err;
1274
1275 ret = 1;
1276
1277 err:
1278 BN_CTX_end(ctx);
1279#ifndef FIPS_MODULE
1280 BN_CTX_free(new_ctx);
1281#endif
1282 return ret;
1283}
1284
1285/*-
1286 * Default behavior, if group->meth->field_inverse_mod_ord is NULL:
1287 * - When group->order is even, this function returns an error.
1288 * - When group->order is otherwise composite, the correctness
1289 * of the output is not guaranteed.
1290 * - When x is outside the range [1, group->order), the correctness
1291 * of the output is not guaranteed.
1292 * - Otherwise, this function returns the multiplicative inverse in the
1293 * range [1, group->order).
1294 *
1295 * EC_METHODs must implement their own field_inverse_mod_ord for
1296 * other functionality.
1297 */
1298int ossl_ec_group_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
1299 const BIGNUM *x, BN_CTX *ctx)
1300{
1301 if (group->meth->field_inverse_mod_ord != NULL)
1302 return group->meth->field_inverse_mod_ord(group, res, x, ctx);
1303 else
1304 return ec_field_inverse_mod_ord(group, res, x, ctx);
1305}
1306
1307/*-
1308 * Coordinate blinding for EC_POINT.
1309 *
1310 * The underlying EC_METHOD can optionally implement this function:
1311 * underlying implementations should return 0 on errors, or 1 on
1312 * success.
1313 *
1314 * This wrapper returns 1 in case the underlying EC_METHOD does not
1315 * support coordinate blinding.
1316 */
1317int ossl_ec_point_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
1318 BN_CTX *ctx)
1319{
1320 if (group->meth->blind_coordinates == NULL)
1321 return 1; /* ignore if not implemented */
1322
1323 return group->meth->blind_coordinates(group, p, ctx);
1324}
1325
1326int EC_GROUP_get_basis_type(const EC_GROUP *group)
1327{
1328 int i;
1329
1330 if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field)
1331 /* everything else is currently not supported */
1332 return 0;
1333
1334 /* Find the last non-zero element of group->poly[] */
1335 for (i = 0;
1336 i < (int)OSSL_NELEM(group->poly) && group->poly[i] != 0;
1337 i++)
1338 continue;
1339
1340 if (i == 4)
1341 return NID_X9_62_ppBasis;
1342 else if (i == 2)
1343 return NID_X9_62_tpBasis;
1344 else
1345 /* everything else is currently not supported */
1346 return 0;
1347}
1348
1349#ifndef OPENSSL_NO_EC2M
1350int EC_GROUP_get_trinomial_basis(const EC_GROUP *group, unsigned int *k)
1351{
1352 if (group == NULL)
1353 return 0;
1354
1355 if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field
1356 || !((group->poly[0] != 0) && (group->poly[1] != 0)
1357 && (group->poly[2] == 0))) {
1358 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1359 return 0;
1360 }
1361
1362 if (k)
1363 *k = group->poly[1];
1364
1365 return 1;
1366}
1367
1368int EC_GROUP_get_pentanomial_basis(const EC_GROUP *group, unsigned int *k1,
1369 unsigned int *k2, unsigned int *k3)
1370{
1371 if (group == NULL)
1372 return 0;
1373
1374 if (EC_GROUP_get_field_type(group) != NID_X9_62_characteristic_two_field
1375 || !((group->poly[0] != 0) && (group->poly[1] != 0)
1376 && (group->poly[2] != 0) && (group->poly[3] != 0)
1377 && (group->poly[4] == 0))) {
1378 ERR_raise(ERR_LIB_EC, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
1379 return 0;
1380 }
1381
1382 if (k1)
1383 *k1 = group->poly[3];
1384 if (k2)
1385 *k2 = group->poly[2];
1386 if (k3)
1387 *k3 = group->poly[1];
1388
1389 return 1;
1390}
1391#endif
1392
1393#ifndef FIPS_MODULE
1394/*
1395 * Check if the explicit parameters group matches any built-in curves.
1396 *
1397 * We create a copy of the group just built, so that we can remove optional
1398 * fields for the lookup: we do this to avoid the possibility that one of
1399 * the optional parameters is used to force the library into using a less
1400 * performant and less secure EC_METHOD instead of the specialized one.
1401 * In any case, `seed` is not really used in any computation, while a
1402 * cofactor different from the one in the built-in table is just
1403 * mathematically wrong anyway and should not be used.
1404 */
1405static EC_GROUP *ec_group_explicit_to_named(const EC_GROUP *group,
1406 OSSL_LIB_CTX *libctx,
1407 const char *propq,
1408 BN_CTX *ctx)
1409{
1410 EC_GROUP *ret_group = NULL, *dup = NULL;
1411 int curve_name_nid;
1412
1413 const EC_POINT *point = EC_GROUP_get0_generator(group);
1414 const BIGNUM *order = EC_GROUP_get0_order(group);
1415 int no_seed = (EC_GROUP_get0_seed(group) == NULL);
1416
1417 if ((dup = EC_GROUP_dup(group)) == NULL
1418 || EC_GROUP_set_seed(dup, NULL, 0) != 1
1419 || !EC_GROUP_set_generator(dup, point, order, NULL))
1420 goto err;
1421 if ((curve_name_nid = ossl_ec_curve_nid_from_params(dup, ctx)) != NID_undef) {
1422 /*
1423 * The input explicit parameters successfully matched one of the
1424 * built-in curves: often for built-in curves we have specialized
1425 * methods with better performance and hardening.
1426 *
1427 * In this case we replace the `EC_GROUP` created through explicit
1428 * parameters with one created from a named group.
1429 */
1430
1431# ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
1432 /*
1433 * NID_wap_wsg_idm_ecid_wtls12 and NID_secp224r1 are both aliases for
1434 * the same curve, we prefer the SECP nid when matching explicit
1435 * parameters as that is associated with a specialized EC_METHOD.
1436 */
1437 if (curve_name_nid == NID_wap_wsg_idm_ecid_wtls12)
1438 curve_name_nid = NID_secp224r1;
1439# endif /* !def(OPENSSL_NO_EC_NISTP_64_GCC_128) */
1440
1441 ret_group = EC_GROUP_new_by_curve_name_ex(libctx, propq, curve_name_nid);
1442 if (ret_group == NULL)
1443 goto err;
1444
1445 /*
1446 * Set the flag so that EC_GROUPs created from explicit parameters are
1447 * serialized using explicit parameters by default.
1448 */
1449 EC_GROUP_set_asn1_flag(ret_group, OPENSSL_EC_EXPLICIT_CURVE);
1450
1451 /*
1452 * If the input params do not contain the optional seed field we make
1453 * sure it is not added to the returned group.
1454 *
1455 * The seed field is not really used inside libcrypto anyway, and
1456 * adding it to parsed explicit parameter keys would alter their DER
1457 * encoding output (because of the extra field) which could impact
1458 * applications fingerprinting keys by their DER encoding.
1459 */
1460 if (no_seed) {
1461 if (EC_GROUP_set_seed(ret_group, NULL, 0) != 1)
1462 goto err;
1463 }
1464 } else {
1465 ret_group = (EC_GROUP *)group;
1466 }
1467 EC_GROUP_free(dup);
1468 return ret_group;
1469err:
1470 EC_GROUP_free(dup);
1471 EC_GROUP_free(ret_group);
1472 return NULL;
1473}
1474#endif /* FIPS_MODULE */
1475
1476static EC_GROUP *group_new_from_name(const OSSL_PARAM *p,
1477 OSSL_LIB_CTX *libctx, const char *propq)
1478{
1479 int ok = 0, nid;
1480 const char *curve_name = NULL;
1481
1482 switch (p->data_type) {
1483 case OSSL_PARAM_UTF8_STRING:
1484 /* The OSSL_PARAM functions have no support for this */
1485 curve_name = p->data;
1486 ok = (curve_name != NULL);
1487 break;
1488 case OSSL_PARAM_UTF8_PTR:
1489 ok = OSSL_PARAM_get_utf8_ptr(p, &curve_name);
1490 break;
1491 }
1492
1493 if (ok) {
1494 nid = ossl_ec_curve_name2nid(curve_name);
1495 if (nid == NID_undef) {
1496 ERR_raise(ERR_LIB_EC, EC_R_INVALID_CURVE);
1497 return NULL;
1498 } else {
1499 return EC_GROUP_new_by_curve_name_ex(libctx, propq, nid);
1500 }
1501 }
1502 return NULL;
1503}
1504
1505/* These parameters can be set directly into an EC_GROUP */
1506int ossl_ec_group_set_params(EC_GROUP *group, const OSSL_PARAM params[])
1507{
1508 int encoding_flag = -1, format = -1;
1509 const OSSL_PARAM *p;
1510
1511 p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_POINT_CONVERSION_FORMAT);
1512 if (p != NULL) {
1513 if (!ossl_ec_pt_format_param2id(p, &format)) {
1514 ERR_raise(ERR_LIB_EC, EC_R_INVALID_FORM);
1515 return 0;
1516 }
1517 EC_GROUP_set_point_conversion_form(group, format);
1518 }
1519
1520 p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ENCODING);
1521 if (p != NULL) {
1522 if (!ossl_ec_encoding_param2id(p, &encoding_flag)) {
1523 ERR_raise(ERR_LIB_EC, EC_R_INVALID_FORM);
1524 return 0;
1525 }
1526 EC_GROUP_set_asn1_flag(group, encoding_flag);
1527 }
1528 /* Optional seed */
1529 p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_SEED);
1530 if (p != NULL) {
1531 /* The seed is allowed to be NULL */
1532 if (p->data_type != OSSL_PARAM_OCTET_STRING
1533 || !EC_GROUP_set_seed(group, p->data, p->data_size)) {
1534 ERR_raise(ERR_LIB_EC, EC_R_INVALID_SEED);
1535 return 0;
1536 }
1537 }
1538 return 1;
1539}
1540
1541EC_GROUP *EC_GROUP_new_from_params(const OSSL_PARAM params[],
1542 OSSL_LIB_CTX *libctx, const char *propq)
1543{
1544 const OSSL_PARAM *ptmp;
1545 EC_GROUP *group = NULL;
1546
1547#ifndef FIPS_MODULE
1548 const OSSL_PARAM *pa, *pb;
1549 int ok = 0;
1550 EC_GROUP *named_group = NULL;
1551 BIGNUM *p = NULL, *a = NULL, *b = NULL, *order = NULL, *cofactor = NULL;
1552 EC_POINT *point = NULL;
1553 int field_bits = 0;
1554 int is_prime_field = 1;
1555 BN_CTX *bnctx = NULL;
1556 const unsigned char *buf = NULL;
1557 int encoding_flag = -1;
1558#endif
1559
1560 /* This is the simple named group case */
1561 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_GROUP_NAME);
1562 if (ptmp != NULL) {
1563 int decoded = 0;
1564
1565 if ((group = group_new_from_name(ptmp, libctx, propq)) == NULL)
1566 return NULL;
1567 if (!ossl_ec_group_set_params(group, params)) {
1568 EC_GROUP_free(group);
1569 return NULL;
1570 }
1571
1572 ptmp = OSSL_PARAM_locate_const(params,
1573 OSSL_PKEY_PARAM_EC_DECODED_FROM_EXPLICIT_PARAMS);
1574 if (ptmp != NULL && !OSSL_PARAM_get_int(ptmp, &decoded)) {
1575 ERR_raise(ERR_LIB_EC, EC_R_WRONG_CURVE_PARAMETERS);
1576 EC_GROUP_free(group);
1577 return NULL;
1578 }
1579 group->decoded_from_explicit_params = decoded > 0;
1580 return group;
1581 }
1582#ifdef FIPS_MODULE
1583 ERR_raise(ERR_LIB_EC, EC_R_EXPLICIT_PARAMS_NOT_SUPPORTED);
1584 return NULL;
1585#else
1586 /* If it gets here then we are trying explicit parameters */
1587 bnctx = BN_CTX_new_ex(libctx);
1588 if (bnctx == NULL) {
1589 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
1590 return 0;
1591 }
1592 BN_CTX_start(bnctx);
1593
1594 p = BN_CTX_get(bnctx);
1595 a = BN_CTX_get(bnctx);
1596 b = BN_CTX_get(bnctx);
1597 order = BN_CTX_get(bnctx);
1598 if (order == NULL) {
1599 ERR_raise(ERR_LIB_EC, ERR_R_BN_LIB);
1600 goto err;
1601 }
1602
1603 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_FIELD_TYPE);
1604 if (ptmp == NULL || ptmp->data_type != OSSL_PARAM_UTF8_STRING) {
1605 ERR_raise(ERR_LIB_EC, EC_R_INVALID_FIELD);
1606 goto err;
1607 }
1608 if (OPENSSL_strcasecmp(ptmp->data, SN_X9_62_prime_field) == 0) {
1609 is_prime_field = 1;
1610 } else if (OPENSSL_strcasecmp(ptmp->data,
1611 SN_X9_62_characteristic_two_field) == 0) {
1612 is_prime_field = 0;
1613 } else {
1614 /* Invalid field */
1615 ERR_raise(ERR_LIB_EC, EC_R_UNSUPPORTED_FIELD);
1616 goto err;
1617 }
1618
1619 pa = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_A);
1620 if (!OSSL_PARAM_get_BN(pa, &a)) {
1621 ERR_raise(ERR_LIB_EC, EC_R_INVALID_A);
1622 goto err;
1623 }
1624 pb = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_B);
1625 if (!OSSL_PARAM_get_BN(pb, &b)) {
1626 ERR_raise(ERR_LIB_EC, EC_R_INVALID_B);
1627 goto err;
1628 }
1629
1630 /* extract the prime number or irreducible polynomial */
1631 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_P);
1632 if (!OSSL_PARAM_get_BN(ptmp, &p)) {
1633 ERR_raise(ERR_LIB_EC, EC_R_INVALID_P);
1634 goto err;
1635 }
1636
1637 if (is_prime_field) {
1638 if (BN_is_negative(p) || BN_is_zero(p)) {
1639 ERR_raise(ERR_LIB_EC, EC_R_INVALID_P);
1640 goto err;
1641 }
1642 field_bits = BN_num_bits(p);
1643 if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS) {
1644 ERR_raise(ERR_LIB_EC, EC_R_FIELD_TOO_LARGE);
1645 goto err;
1646 }
1647
1648 /* create the EC_GROUP structure */
1649 group = EC_GROUP_new_curve_GFp(p, a, b, bnctx);
1650 } else {
1651# ifdef OPENSSL_NO_EC2M
1652 ERR_raise(ERR_LIB_EC, EC_R_GF2M_NOT_SUPPORTED);
1653 goto err;
1654# else
1655 /* create the EC_GROUP structure */
1656 group = EC_GROUP_new_curve_GF2m(p, a, b, NULL);
1657 if (group != NULL) {
1658 field_bits = EC_GROUP_get_degree(group);
1659 if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS) {
1660 ERR_raise(ERR_LIB_EC, EC_R_FIELD_TOO_LARGE);
1661 goto err;
1662 }
1663 }
1664# endif /* OPENSSL_NO_EC2M */
1665 }
1666
1667 if (group == NULL) {
1668 ERR_raise(ERR_LIB_EC, ERR_R_EC_LIB);
1669 goto err;
1670 }
1671
1672 /* Optional seed */
1673 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_SEED);
1674 if (ptmp != NULL) {
1675 if (ptmp->data_type != OSSL_PARAM_OCTET_STRING) {
1676 ERR_raise(ERR_LIB_EC, EC_R_INVALID_SEED);
1677 goto err;
1678 }
1679 if (!EC_GROUP_set_seed(group, ptmp->data, ptmp->data_size))
1680 goto err;
1681 }
1682
1683 /* generator base point */
1684 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_GENERATOR);
1685 if (ptmp == NULL
1686 || ptmp->data_type != OSSL_PARAM_OCTET_STRING) {
1687 ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1688 goto err;
1689 }
1690 buf = (const unsigned char *)(ptmp->data);
1691 if ((point = EC_POINT_new(group)) == NULL)
1692 goto err;
1693 EC_GROUP_set_point_conversion_form(group,
1694 (point_conversion_form_t)buf[0] & ~0x01);
1695 if (!EC_POINT_oct2point(group, point, buf, ptmp->data_size, bnctx)) {
1696 ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1697 goto err;
1698 }
1699
1700 /* order */
1701 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ORDER);
1702 if (!OSSL_PARAM_get_BN(ptmp, &order)
1703 || (BN_is_negative(order) || BN_is_zero(order))
1704 || (BN_num_bits(order) > (int)field_bits + 1)) { /* Hasse bound */
1705 ERR_raise(ERR_LIB_EC, EC_R_INVALID_GROUP_ORDER);
1706 goto err;
1707 }
1708
1709 /* Optional cofactor */
1710 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_COFACTOR);
1711 if (ptmp != NULL) {
1712 cofactor = BN_CTX_get(bnctx);
1713 if (cofactor == NULL || !OSSL_PARAM_get_BN(ptmp, &cofactor)) {
1714 ERR_raise(ERR_LIB_EC, EC_R_INVALID_COFACTOR);
1715 goto err;
1716 }
1717 }
1718
1719 /* set the generator, order and cofactor (if present) */
1720 if (!EC_GROUP_set_generator(group, point, order, cofactor)) {
1721 ERR_raise(ERR_LIB_EC, EC_R_INVALID_GENERATOR);
1722 goto err;
1723 }
1724
1725 named_group = ec_group_explicit_to_named(group, libctx, propq, bnctx);
1726 if (named_group == NULL) {
1727 ERR_raise(ERR_LIB_EC, EC_R_INVALID_NAMED_GROUP_CONVERSION);
1728 goto err;
1729 }
1730 if (named_group == group) {
1731 /*
1732 * If we did not find a named group then the encoding should be explicit
1733 * if it was specified
1734 */
1735 ptmp = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_ENCODING);
1736 if (ptmp != NULL
1737 && !ossl_ec_encoding_param2id(ptmp, &encoding_flag)) {
1738 ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
1739 goto err;
1740 }
1741 if (encoding_flag == OPENSSL_EC_NAMED_CURVE) {
1742 ERR_raise(ERR_LIB_EC, EC_R_INVALID_ENCODING);
1743 goto err;
1744 }
1745 EC_GROUP_set_asn1_flag(group, OPENSSL_EC_EXPLICIT_CURVE);
1746 } else {
1747 EC_GROUP_free(group);
1748 group = named_group;
1749 }
1750 /* We've imported the group from explicit parameters, set it so. */
1751 group->decoded_from_explicit_params = 1;
1752 ok = 1;
1753 err:
1754 if (!ok) {
1755 EC_GROUP_free(group);
1756 group = NULL;
1757 }
1758 EC_POINT_free(point);
1759 BN_CTX_end(bnctx);
1760 BN_CTX_free(bnctx);
1761
1762 return group;
1763#endif /* FIPS_MODULE */
1764}
1765
1766OSSL_PARAM *EC_GROUP_to_params(const EC_GROUP *group, OSSL_LIB_CTX *libctx,
1767 const char *propq, BN_CTX *bnctx)
1768{
1769 OSSL_PARAM_BLD *tmpl = NULL;
1770 BN_CTX *new_bnctx = NULL;
1771 unsigned char *gen_buf = NULL;
1772 OSSL_PARAM *params = NULL;
1773
1774 if (group == NULL)
1775 goto err;
1776
1777 tmpl = OSSL_PARAM_BLD_new();
1778 if (tmpl == NULL)
1779 goto err;
1780
1781 if (bnctx == NULL)
1782 bnctx = new_bnctx = BN_CTX_new_ex(libctx);
1783 if (bnctx == NULL)
1784 goto err;
1785 BN_CTX_start(bnctx);
1786
1787 if (!ossl_ec_group_todata(
1788 group, tmpl, NULL, libctx, propq, bnctx, &gen_buf))
1789 goto err;
1790
1791 params = OSSL_PARAM_BLD_to_param(tmpl);
1792
1793 err:
1794 OSSL_PARAM_BLD_free(tmpl);
1795 OPENSSL_free(gen_buf);
1796 BN_CTX_end(bnctx);
1797 BN_CTX_free(new_bnctx);
1798 return params;
1799}
Mirror of https://github.com/openssl/openssl.git