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-rw-r--r--src/lib/libcrypto/sm2/sm2_crypt.c632
1 files changed, 632 insertions, 0 deletions
diff --git a/src/lib/libcrypto/sm2/sm2_crypt.c b/src/lib/libcrypto/sm2/sm2_crypt.c
new file mode 100644
index 0000000000..2bb3b8ff63
--- /dev/null
+++ b/src/lib/libcrypto/sm2/sm2_crypt.c
@@ -0,0 +1,632 @@
1/* $OpenBSD: sm2_crypt.c,v 1.1.1.1 2021/08/18 16:04:32 tb Exp $ */
2/*
3 * Copyright (c) 2017, 2019 Ribose Inc
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#ifndef OPENSSL_NO_SM2
19
20#include <string.h>
21
22#include <openssl/asn1.h>
23#include <openssl/asn1t.h>
24#include <openssl/bn.h>
25#include <openssl/err.h>
26#include <openssl/evp.h>
27#include <openssl/sm2.h>
28
29#include "sm2_locl.h"
30
31typedef struct SM2_Ciphertext_st SM2_Ciphertext;
32
33SM2_Ciphertext *SM2_Ciphertext_new(void);
34void SM2_Ciphertext_free(SM2_Ciphertext *a);
35SM2_Ciphertext *d2i_SM2_Ciphertext(SM2_Ciphertext **a, const unsigned char **in,
36 long len);
37int i2d_SM2_Ciphertext(SM2_Ciphertext *a, unsigned char **out);
38
39struct SM2_Ciphertext_st {
40 BIGNUM *C1x;
41 BIGNUM *C1y;
42 ASN1_OCTET_STRING *C3;
43 ASN1_OCTET_STRING *C2;
44};
45
46static const ASN1_TEMPLATE SM2_Ciphertext_seq_tt[] = {
47 {
48 .flags = 0,
49 .tag = 0,
50 .offset = offsetof(SM2_Ciphertext, C1x),
51 .field_name = "C1x",
52 .item = &BIGNUM_it,
53 },
54 {
55 .flags = 0,
56 .tag = 0,
57 .offset = offsetof(SM2_Ciphertext, C1y),
58 .field_name = "C1y",
59 .item = &BIGNUM_it,
60 },
61 {
62 .flags = 0,
63 .tag = 0,
64 .offset = offsetof(SM2_Ciphertext, C3),
65 .field_name = "C3",
66 .item = &ASN1_OCTET_STRING_it,
67 },
68 {
69 .flags = 0,
70 .tag = 0,
71 .offset = offsetof(SM2_Ciphertext, C2),
72 .field_name = "C2",
73 .item = &ASN1_OCTET_STRING_it,
74 },
75};
76
77const ASN1_ITEM SM2_Ciphertext_it = {
78 .itype = ASN1_ITYPE_SEQUENCE,
79 .utype = V_ASN1_SEQUENCE,
80 .templates = SM2_Ciphertext_seq_tt,
81 .tcount = sizeof(SM2_Ciphertext_seq_tt) / sizeof(ASN1_TEMPLATE),
82 .funcs = NULL,
83 .size = sizeof(SM2_Ciphertext),
84 .sname = "SM2_Ciphertext",
85};
86
87SM2_Ciphertext *
88d2i_SM2_Ciphertext(SM2_Ciphertext **a, const unsigned char **in, long len)
89{
90 return (SM2_Ciphertext *) ASN1_item_d2i((ASN1_VALUE **)a, in, len,
91 &SM2_Ciphertext_it);
92}
93
94int
95i2d_SM2_Ciphertext(SM2_Ciphertext *a, unsigned char **out)
96{
97 return ASN1_item_i2d((ASN1_VALUE *)a, out, &SM2_Ciphertext_it);
98}
99
100SM2_Ciphertext *
101SM2_Ciphertext_new(void)
102{
103 return (SM2_Ciphertext *)ASN1_item_new(&SM2_Ciphertext_it);
104}
105
106void
107SM2_Ciphertext_free(SM2_Ciphertext *a)
108{
109 ASN1_item_free((ASN1_VALUE *)a, &SM2_Ciphertext_it);
110}
111
112static size_t
113ec_field_size(const EC_GROUP *group)
114{
115 /* Is there some simpler way to do this? */
116 BIGNUM *p;
117 size_t field_size = 0;
118
119 if ((p = BN_new()) == NULL)
120 goto err;
121 if (!EC_GROUP_get_curve(group, p, NULL, NULL, NULL))
122 goto err;
123 field_size = BN_num_bytes(p);
124 err:
125 BN_free(p);
126 return field_size;
127}
128
129int
130SM2_plaintext_size(const EC_KEY *key, const EVP_MD *digest, size_t msg_len,
131 size_t *pl_size)
132{
133 size_t field_size, overhead;
134 int md_size;
135
136 if ((field_size = ec_field_size(EC_KEY_get0_group(key))) == 0) {
137 SM2error(SM2_R_INVALID_FIELD);
138 return 0;
139 }
140
141 if ((md_size = EVP_MD_size(digest)) < 0) {
142 SM2error(SM2_R_INVALID_DIGEST);
143 return 0;
144 }
145
146 overhead = 10 + 2 * field_size + md_size;
147 if (msg_len <= overhead) {
148 SM2error(SM2_R_INVALID_ARGUMENT);
149 return 0;
150 }
151
152 *pl_size = msg_len - overhead;
153 return 1;
154}
155
156int
157SM2_ciphertext_size(const EC_KEY *key, const EVP_MD *digest, size_t msg_len,
158 size_t *c_size)
159{
160 size_t asn_size, field_size;
161 int md_size;
162
163 if ((field_size = ec_field_size(EC_KEY_get0_group(key))) == 0) {
164 SM2error(SM2_R_INVALID_FIELD);
165 return 0;
166 }
167
168 if ((md_size = EVP_MD_size(digest)) < 0) {
169 SM2error(SM2_R_INVALID_DIGEST);
170 return 0;
171 }
172
173 asn_size = 2 * ASN1_object_size(0, field_size + 1, V_ASN1_INTEGER) +
174 ASN1_object_size(0, md_size, V_ASN1_OCTET_STRING) +
175 ASN1_object_size(0, msg_len, V_ASN1_OCTET_STRING);
176
177 *c_size = ASN1_object_size(1, asn_size, V_ASN1_SEQUENCE);
178 return 1;
179}
180
181int
182sm2_kdf(uint8_t *key, size_t key_len, uint8_t *secret, size_t secret_len,
183 const EVP_MD *digest)
184{
185 EVP_MD_CTX *hash;
186 uint8_t *hash_buf = NULL;
187 uint32_t ctr = 1;
188 uint8_t ctr_buf[4] = {0};
189 size_t hadd, hlen;
190 int rc = 0;
191
192 if ((hash = EVP_MD_CTX_new()) == NULL) {
193 SM2error(ERR_R_MALLOC_FAILURE);
194 goto err;
195 }
196
197 if ((hlen = EVP_MD_size(digest)) < 0) {
198 SM2error(SM2_R_INVALID_DIGEST);
199 goto err;
200 }
201 if ((hash_buf = malloc(hlen)) == NULL) {
202 SM2error(ERR_R_MALLOC_FAILURE);
203 goto err;
204 }
205
206 EVP_MD_CTX_init(hash);
207 while ((key_len > 0) && (ctr != 0)) {
208 if (!EVP_DigestInit_ex(hash, digest, NULL)) {
209 SM2error(ERR_R_EVP_LIB);
210 goto err;
211 }
212 if (!EVP_DigestUpdate(hash, secret, secret_len)) {
213 SM2error(ERR_R_EVP_LIB);
214 goto err;
215 }
216
217 /* big-endian counter representation */
218 ctr_buf[0] = (ctr >> 24) & 0xff;
219 ctr_buf[1] = (ctr >> 16) & 0xff;
220 ctr_buf[2] = (ctr >> 8) & 0xff;
221 ctr_buf[3] = ctr & 0xff;
222 ctr++;
223
224 if (!EVP_DigestUpdate(hash, ctr_buf, 4)) {
225 SM2error(ERR_R_EVP_LIB);
226 goto err;
227 }
228 if (!EVP_DigestFinal(hash, hash_buf, NULL)) {
229 SM2error(ERR_R_EVP_LIB);
230 goto err;
231 }
232
233 hadd = key_len > hlen ? hlen : key_len;
234 memcpy(key, hash_buf, hadd);
235 memset(hash_buf, 0, hlen);
236 key_len -= hadd;
237 key += hadd;
238 }
239
240 rc = 1;
241 err:
242 free(hash_buf);
243 EVP_MD_CTX_free(hash);
244 return rc;
245}
246
247int
248SM2_encrypt(const EC_KEY *key, const EVP_MD *digest, const uint8_t *msg,
249 size_t msg_len, uint8_t *ciphertext_buf, size_t *ciphertext_len)
250{
251 SM2_Ciphertext ctext_struct;
252 EVP_MD_CTX *hash = NULL;
253 BN_CTX *ctx = NULL;
254 BIGNUM *order = NULL;
255 BIGNUM *k, *x1, *y1, *x2, *y2;
256 const EC_GROUP *group;
257 const EC_POINT *P;
258 EC_POINT *kG = NULL, *kP = NULL;
259 uint8_t *msg_mask = NULL, *x2y2 = NULL, *C3 = NULL;
260 size_t C3_size, field_size, i, x2size, y2size;
261 int rc = 0;
262 int clen;
263
264 ctext_struct.C2 = NULL;
265 ctext_struct.C3 = NULL;
266
267 if ((hash = EVP_MD_CTX_new()) == NULL) {
268 SM2error(ERR_R_MALLOC_FAILURE);
269 goto err;
270 }
271
272 if ((group = EC_KEY_get0_group(key)) == NULL) {
273 SM2error(SM2_R_INVALID_KEY);
274 goto err;
275 }
276
277 if ((order = BN_new()) == NULL) {
278 SM2error(ERR_R_MALLOC_FAILURE);
279 goto err;
280 }
281
282 if (!EC_GROUP_get_order(group, order, NULL)) {
283 SM2error(SM2_R_INVALID_GROUP_ORDER);
284 goto err;
285 }
286
287 if ((P = EC_KEY_get0_public_key(key)) == NULL) {
288 SM2error(SM2_R_INVALID_KEY);
289 goto err;
290 }
291
292 if ((field_size = ec_field_size(group)) == 0) {
293 SM2error(SM2_R_INVALID_FIELD);
294 goto err;
295 }
296
297 if ((C3_size = EVP_MD_size(digest)) < 0) {
298 SM2error(SM2_R_INVALID_DIGEST);
299 goto err;
300 }
301
302 if ((kG = EC_POINT_new(group)) == NULL) {
303 SM2error(ERR_R_MALLOC_FAILURE);
304 goto err;
305 }
306 if ((kP = EC_POINT_new(group)) == NULL) {
307 SM2error(ERR_R_MALLOC_FAILURE);
308 goto err;
309 }
310
311 if ((ctx = BN_CTX_new()) == NULL) {
312 SM2error(ERR_R_MALLOC_FAILURE);
313 goto err;
314 }
315
316 BN_CTX_start(ctx);
317 if ((k = BN_CTX_get(ctx)) == NULL) {
318 SM2error(ERR_R_BN_LIB);
319 goto err;
320 }
321 if ((x1 = BN_CTX_get(ctx)) == NULL) {
322 SM2error(ERR_R_BN_LIB);
323 goto err;
324 }
325 if ((x2 = BN_CTX_get(ctx)) == NULL) {
326 SM2error(ERR_R_BN_LIB);
327 goto err;
328 }
329 if ((y1 = BN_CTX_get(ctx)) == NULL) {
330 SM2error(ERR_R_BN_LIB);
331 goto err;
332 }
333 if ((y2 = BN_CTX_get(ctx)) == NULL) {
334 SM2error(ERR_R_BN_LIB);
335 goto err;
336 }
337
338 if ((x2y2 = calloc(2, field_size)) == NULL) {
339 SM2error(ERR_R_MALLOC_FAILURE);
340 goto err;
341 }
342
343 if ((C3 = calloc(1, C3_size)) == NULL) {
344 SM2error(ERR_R_MALLOC_FAILURE);
345 goto err;
346 }
347
348 memset(ciphertext_buf, 0, *ciphertext_len);
349
350 if (!BN_rand_range(k, order)) {
351 SM2error(SM2_R_RANDOM_NUMBER_GENERATION_FAILED);
352 goto err;
353 }
354
355 if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)) {
356 SM2error(ERR_R_EC_LIB);
357 goto err;
358 }
359
360 if (!EC_POINT_get_affine_coordinates(group, kG, x1, y1, ctx)) {
361 SM2error(ERR_R_EC_LIB);
362 goto err;
363 }
364
365 if (!EC_POINT_mul(group, kP, NULL, P, k, ctx)) {
366 SM2error(ERR_R_EC_LIB);
367 goto err;
368 }
369
370 if (!EC_POINT_get_affine_coordinates(group, kP, x2, y2, ctx)) {
371 SM2error(ERR_R_EC_LIB);
372 goto err;
373 }
374
375 if ((x2size = BN_num_bytes(x2)) > field_size ||
376 (y2size = BN_num_bytes(y2)) > field_size) {
377 SM2error(SM2_R_BIGNUM_OUT_OF_RANGE);
378 goto err;
379 }
380
381 BN_bn2bin(x2, x2y2 + field_size - x2size);
382 BN_bn2bin(y2, x2y2 + 2 * field_size - y2size);
383
384 if ((msg_mask = calloc(1, msg_len)) == NULL) {
385 SM2error(ERR_R_MALLOC_FAILURE);
386 goto err;
387 }
388
389 if (!sm2_kdf(msg_mask, msg_len, x2y2, 2 * field_size, digest)) {
390 SM2error(SM2_R_KDF_FAILURE);
391 goto err;
392 }
393
394 for (i = 0; i != msg_len; i++)
395 msg_mask[i] ^= msg[i];
396
397 if (!EVP_DigestInit(hash, digest)) {
398 SM2error(ERR_R_EVP_LIB);
399 goto err;
400 }
401
402 if (!EVP_DigestUpdate(hash, x2y2, field_size)) {
403 SM2error(ERR_R_EVP_LIB);
404 goto err;
405 }
406
407 if (!EVP_DigestUpdate(hash, msg, msg_len)) {
408 SM2error(ERR_R_EVP_LIB);
409 goto err;
410 }
411
412 if (!EVP_DigestUpdate(hash, x2y2 + field_size, field_size)) {
413 SM2error(ERR_R_EVP_LIB);
414 goto err;
415 }
416
417 if (!EVP_DigestFinal(hash, C3, NULL)) {
418 SM2error(ERR_R_EVP_LIB);
419 goto err;
420 }
421
422 ctext_struct.C1x = x1;
423 ctext_struct.C1y = y1;
424 if ((ctext_struct.C3 = ASN1_OCTET_STRING_new()) == NULL) {
425 SM2error(ERR_R_MALLOC_FAILURE);
426 goto err;
427 }
428 if ((ctext_struct.C2 = ASN1_OCTET_STRING_new()) == NULL) {
429 SM2error(ERR_R_MALLOC_FAILURE);
430 goto err;
431 }
432 if (!ASN1_OCTET_STRING_set(ctext_struct.C3, C3, C3_size)) {
433 SM2error(ERR_R_INTERNAL_ERROR);
434 goto err;
435 }
436 if (!ASN1_OCTET_STRING_set(ctext_struct.C2, msg_mask, msg_len)) {
437 SM2error(ERR_R_INTERNAL_ERROR);
438 goto err;
439 }
440
441 if ((clen = i2d_SM2_Ciphertext(&ctext_struct, &ciphertext_buf)) < 0) {
442 SM2error(ERR_R_INTERNAL_ERROR);
443 goto err;
444 }
445
446 *ciphertext_len = clen;
447 rc = 1;
448
449 err:
450 ASN1_OCTET_STRING_free(ctext_struct.C2);
451 ASN1_OCTET_STRING_free(ctext_struct.C3);
452 free(msg_mask);
453 free(x2y2);
454 free(C3);
455 EVP_MD_CTX_free(hash);
456 BN_CTX_end(ctx);
457 BN_CTX_free(ctx);
458 EC_POINT_free(kG);
459 EC_POINT_free(kP);
460 BN_free(order);
461 return rc;
462}
463
464int
465SM2_decrypt(const EC_KEY *key, const EVP_MD *digest, const uint8_t *ciphertext,
466 size_t ciphertext_len, uint8_t *ptext_buf, size_t *ptext_len)
467{
468 SM2_Ciphertext *sm2_ctext = NULL;
469 EVP_MD_CTX *hash = NULL;
470 BN_CTX *ctx = NULL;
471 BIGNUM *x2, *y2;
472 const EC_GROUP *group;
473 EC_POINT *C1 = NULL;
474 const uint8_t *C2, *C3;
475 uint8_t *computed_C3 = NULL, *msg_mask = NULL, *x2y2 = NULL;
476 size_t field_size, x2size, y2size;
477 int msg_len = 0, rc = 0;
478 int hash_size, i;
479
480 if ((group = EC_KEY_get0_group(key)) == NULL) {
481 SM2error(SM2_R_INVALID_KEY);
482 goto err;
483 }
484
485 if ((field_size = ec_field_size(group)) == 0) {
486 SM2error(SM2_R_INVALID_FIELD);
487 goto err;
488 }
489
490 if ((hash_size = EVP_MD_size(digest)) < 0) {
491 SM2error(SM2_R_INVALID_DIGEST);
492 goto err;
493 }
494
495 memset(ptext_buf, 0xFF, *ptext_len);
496
497 if ((sm2_ctext = d2i_SM2_Ciphertext(NULL, &ciphertext,
498 ciphertext_len)) == NULL) {
499 SM2error(SM2_R_ASN1_ERROR);
500 goto err;
501 }
502
503 if (sm2_ctext->C3->length != hash_size) {
504 SM2error(SM2_R_INVALID_ENCODING);
505 goto err;
506 }
507
508 C2 = sm2_ctext->C2->data;
509 C3 = sm2_ctext->C3->data;
510 msg_len = sm2_ctext->C2->length;
511
512 if ((ctx = BN_CTX_new()) == NULL) {
513 SM2error(ERR_R_MALLOC_FAILURE);
514 goto err;
515 }
516
517 BN_CTX_start(ctx);
518 if ((x2 = BN_CTX_get(ctx)) == NULL) {
519 SM2error(ERR_R_BN_LIB);
520 goto err;
521 }
522 if ((y2 = BN_CTX_get(ctx)) == NULL) {
523 SM2error(ERR_R_BN_LIB);
524 goto err;
525 }
526
527 if ((msg_mask = calloc(1, msg_len)) == NULL) {
528 SM2error(ERR_R_MALLOC_FAILURE);
529 goto err;
530 }
531 if ((x2y2 = calloc(2, field_size)) == NULL) {
532 SM2error(ERR_R_MALLOC_FAILURE);
533 goto err;
534 }
535 if ((computed_C3 = calloc(1, hash_size)) == NULL) {
536 SM2error(ERR_R_MALLOC_FAILURE);
537 goto err;
538 }
539
540 if ((C1 = EC_POINT_new(group)) == NULL) {
541 SM2error(ERR_R_MALLOC_FAILURE);
542 goto err;
543 }
544
545 if (!EC_POINT_set_affine_coordinates(group, C1, sm2_ctext->C1x,
546 sm2_ctext->C1y, ctx))
547 {
548 SM2error(ERR_R_EC_LIB);
549 goto err;
550 }
551
552 if (!EC_POINT_mul(group, C1, NULL, C1, EC_KEY_get0_private_key(key),
553 ctx)) {
554 SM2error(ERR_R_EC_LIB);
555 goto err;
556 }
557
558 if (!EC_POINT_get_affine_coordinates(group, C1, x2, y2, ctx)) {
559 SM2error(ERR_R_EC_LIB);
560 goto err;
561 }
562
563 if ((x2size = BN_num_bytes(x2)) > field_size ||
564 (y2size = BN_num_bytes(y2)) > field_size) {
565 SM2error(SM2_R_BIGNUM_OUT_OF_RANGE);
566 goto err;
567 }
568
569 BN_bn2bin(x2, x2y2 + field_size - x2size);
570 BN_bn2bin(y2, x2y2 + 2 * field_size - y2size);
571
572 if (!sm2_kdf(msg_mask, msg_len, x2y2, 2 * field_size, digest)) {
573 SM2error(SM2_R_KDF_FAILURE);
574 goto err;
575 }
576
577 for (i = 0; i != msg_len; ++i)
578 ptext_buf[i] = C2[i] ^ msg_mask[i];
579
580 if ((hash = EVP_MD_CTX_new()) == NULL) {
581 SM2error(ERR_R_EVP_LIB);
582 goto err;
583 }
584
585 if (!EVP_DigestInit(hash, digest)) {
586 SM2error(ERR_R_EVP_LIB);
587 goto err;
588 }
589
590 if (!EVP_DigestUpdate(hash, x2y2, field_size)) {
591 SM2error(ERR_R_EVP_LIB);
592 goto err;
593 }
594
595 if (!EVP_DigestUpdate(hash, ptext_buf, msg_len)) {
596 SM2error(ERR_R_EVP_LIB);
597 goto err;
598 }
599
600 if (!EVP_DigestUpdate(hash, x2y2 + field_size, field_size)) {
601 SM2error(ERR_R_EVP_LIB);
602 goto err;
603 }
604
605 if (!EVP_DigestFinal(hash, computed_C3, NULL)) {
606 SM2error(ERR_R_EVP_LIB);
607 goto err;
608 }
609
610 if (memcmp(computed_C3, C3, hash_size) != 0)
611 goto err;
612
613 rc = 1;
614 *ptext_len = msg_len;
615
616 err:
617 if (rc == 0)
618 memset(ptext_buf, 0, *ptext_len);
619
620 free(msg_mask);
621 free(x2y2);
622 free(computed_C3);
623 EC_POINT_free(C1);
624 BN_CTX_end(ctx);
625 BN_CTX_free(ctx);
626 SM2_Ciphertext_free(sm2_ctext);
627 EVP_MD_CTX_free(hash);
628
629 return rc;
630}
631
632#endif /* OPENSSL_NO_SM2 */
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-04-26 13:03:55 +0000