1/*
2 * Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include "internal/cryptlib.h"
11#include <openssl/asn1t.h>
12#include <openssl/ec.h>
13#include <openssl/evp.h>
14#include "crypto/evp.h"
15#include "crypto/sm2.h"
16#include "crypto/sm2err.h"
17
18/* EC pkey context structure */
19
20typedef struct {
21 /* Key and paramgen group */
22 EC_GROUP *gen_group;
23 /* message digest */
24 const EVP_MD *md;
25 /* Distinguishing Identifier, ISO/IEC 15946-3 */
26 uint8_t *id;
27 size_t id_len;
28 /* id_set indicates if the 'id' field is set (1) or not (0) */
29 int id_set;
30} SM2_PKEY_CTX;
31
32static int pkey_sm2_init(EVP_PKEY_CTX *ctx)
33{
34 SM2_PKEY_CTX *smctx;
35
36 if ((smctx = OPENSSL_zalloc(sizeof(*smctx))) == NULL) {
37 SM2err(SM2_F_PKEY_SM2_INIT, ERR_R_MALLOC_FAILURE);
38 return 0;
39 }
40
41 ctx->data = smctx;
42 return 1;
43}
44
45static void pkey_sm2_cleanup(EVP_PKEY_CTX *ctx)
46{
47 SM2_PKEY_CTX *smctx = ctx->data;
48
49 if (smctx != NULL) {
50 EC_GROUP_free(smctx->gen_group);
51 OPENSSL_free(smctx->id);
52 OPENSSL_free(smctx);
53 ctx->data = NULL;
54 }
55}
56
57static int pkey_sm2_copy(EVP_PKEY_CTX *dst, const EVP_PKEY_CTX *src)
58{
59 SM2_PKEY_CTX *dctx, *sctx;
60
61 if (!pkey_sm2_init(dst))
62 return 0;
63 sctx = src->data;
64 dctx = dst->data;
65 if (sctx->gen_group != NULL) {
66 dctx->gen_group = EC_GROUP_dup(sctx->gen_group);
67 if (dctx->gen_group == NULL) {
68 pkey_sm2_cleanup(dst);
69 return 0;
70 }
71 }
72 if (sctx->id != NULL) {
73 dctx->id = OPENSSL_malloc(sctx->id_len);
74 if (dctx->id == NULL) {
75 SM2err(SM2_F_PKEY_SM2_COPY, ERR_R_MALLOC_FAILURE);
76 pkey_sm2_cleanup(dst);
77 return 0;
78 }
79 memcpy(dctx->id, sctx->id, sctx->id_len);
80 }
81 dctx->id_len = sctx->id_len;
82 dctx->id_set = sctx->id_set;
83 dctx->md = sctx->md;
84
85 return 1;
86}
87
88static int pkey_sm2_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,
89 const unsigned char *tbs, size_t tbslen)
90{
91 int ret;
92 unsigned int sltmp;
93 EC_KEY *ec = ctx->pkey->pkey.ec;
94 const int sig_sz = ECDSA_size(ctx->pkey->pkey.ec);
95
96 if (sig_sz <= 0) {
97 return 0;
98 }
99
100 if (sig == NULL) {
101 *siglen = (size_t)sig_sz;
102 return 1;
103 }
104
105 if (*siglen < (size_t)sig_sz) {
106 SM2err(SM2_F_PKEY_SM2_SIGN, SM2_R_BUFFER_TOO_SMALL);
107 return 0;
108 }
109
110 ret = sm2_sign(tbs, tbslen, sig, &sltmp, ec);
111
112 if (ret <= 0)
113 return ret;
114 *siglen = (size_t)sltmp;
115 return 1;
116}
117
118static int pkey_sm2_verify(EVP_PKEY_CTX *ctx,
119 const unsigned char *sig, size_t siglen,
120 const unsigned char *tbs, size_t tbslen)
121{
122 EC_KEY *ec = ctx->pkey->pkey.ec;
123
124 return sm2_verify(tbs, tbslen, sig, siglen, ec);
125}
126
127static int pkey_sm2_encrypt(EVP_PKEY_CTX *ctx,
128 unsigned char *out, size_t *outlen,
129 const unsigned char *in, size_t inlen)
130{
131 EC_KEY *ec = ctx->pkey->pkey.ec;
132 SM2_PKEY_CTX *dctx = ctx->data;
133 const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;
134
135 if (out == NULL) {
136 if (!sm2_ciphertext_size(ec, md, inlen, outlen))
137 return -1;
138 else
139 return 1;
140 }
141
142 return sm2_encrypt(ec, md, in, inlen, out, outlen);
143}
144
145static int pkey_sm2_decrypt(EVP_PKEY_CTX *ctx,
146 unsigned char *out, size_t *outlen,
147 const unsigned char *in, size_t inlen)
148{
149 EC_KEY *ec = ctx->pkey->pkey.ec;
150 SM2_PKEY_CTX *dctx = ctx->data;
151 const EVP_MD *md = (dctx->md == NULL) ? EVP_sm3() : dctx->md;
152
153 if (out == NULL) {
154 if (!sm2_plaintext_size(ec, md, inlen, outlen))
155 return -1;
156 else
157 return 1;
158 }
159
160 return sm2_decrypt(ec, md, in, inlen, out, outlen);
161}
162
163static int pkey_sm2_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)
164{
165 SM2_PKEY_CTX *smctx = ctx->data;
166 EC_GROUP *group;
167 uint8_t *tmp_id;
168
169 switch (type) {
170 case EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID:
171 group = EC_GROUP_new_by_curve_name(p1);
172 if (group == NULL) {
173 SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_INVALID_CURVE);
174 return 0;
175 }
176 EC_GROUP_free(smctx->gen_group);
177 smctx->gen_group = group;
178 return 1;
179
180 case EVP_PKEY_CTRL_EC_PARAM_ENC:
181 if (smctx->gen_group == NULL) {
182 SM2err(SM2_F_PKEY_SM2_CTRL, SM2_R_NO_PARAMETERS_SET);
183 return 0;
184 }
185 EC_GROUP_set_asn1_flag(smctx->gen_group, p1);
186 return 1;
187
188 case EVP_PKEY_CTRL_MD:
189 smctx->md = p2;
190 return 1;
191
192 case EVP_PKEY_CTRL_GET_MD:
193 *(const EVP_MD **)p2 = smctx->md;
194 return 1;
195
196 case EVP_PKEY_CTRL_SET1_ID:
197 if (p1 > 0) {
198 tmp_id = OPENSSL_malloc(p1);
199 if (tmp_id == NULL) {
200 SM2err(SM2_F_PKEY_SM2_CTRL, ERR_R_MALLOC_FAILURE);
201 return 0;
202 }
203 memcpy(tmp_id, p2, p1);
204 OPENSSL_free(smctx->id);
205 smctx->id = tmp_id;
206 } else {
207 /* set null-ID */
208 OPENSSL_free(smctx->id);
209 smctx->id = NULL;
210 }
211 smctx->id_len = (size_t)p1;
212 smctx->id_set = 1;
213 return 1;
214
215 case EVP_PKEY_CTRL_GET1_ID:
216 memcpy(p2, smctx->id, smctx->id_len);
217 return 1;
218
219 case EVP_PKEY_CTRL_GET1_ID_LEN:
220 *(size_t *)p2 = smctx->id_len;
221 return 1;
222
223 case EVP_PKEY_CTRL_DIGESTINIT:
224 /* nothing to be inited, this is to suppress the error... */
225 return 1;
226
227 default:
228 return -2;
229 }
230}
231
232static int pkey_sm2_ctrl_str(EVP_PKEY_CTX *ctx,
233 const char *type, const char *value)
234{
235 uint8_t *hex_id;
236 long hex_len = 0;
237 int ret = 0;
238
239 if (strcmp(type, "ec_paramgen_curve") == 0) {
240 int nid = NID_undef;
241
242 if (((nid = EC_curve_nist2nid(value)) == NID_undef)
243 && ((nid = OBJ_sn2nid(value)) == NID_undef)
244 && ((nid = OBJ_ln2nid(value)) == NID_undef)) {
245 SM2err(SM2_F_PKEY_SM2_CTRL_STR, SM2_R_INVALID_CURVE);
246 return 0;
247 }
248 return EVP_PKEY_CTX_set_ec_paramgen_curve_nid(ctx, nid);
249 } else if (strcmp(type, "ec_param_enc") == 0) {
250 int param_enc;
251
252 if (strcmp(value, "explicit") == 0)
253 param_enc = 0;
254 else if (strcmp(value, "named_curve") == 0)
255 param_enc = OPENSSL_EC_NAMED_CURVE;
256 else
257 return -2;
258 return EVP_PKEY_CTX_set_ec_param_enc(ctx, param_enc);
259 } else if (strcmp(type, "sm2_id") == 0) {
260 return pkey_sm2_ctrl(ctx, EVP_PKEY_CTRL_SET1_ID,
261 (int)strlen(value), (void *)value);
262 } else if (strcmp(type, "sm2_hex_id") == 0) {
263 /*
264 * TODO(3.0): reconsider the name "sm2_hex_id", OR change
265 * OSSL_PARAM_construct_from_text() / OSSL_PARAM_allocate_from_text()
266 * to handle infix "_hex_"
267 */
268 hex_id = OPENSSL_hexstr2buf((const char *)value, &hex_len);
269 if (hex_id == NULL) {
270 SM2err(SM2_F_PKEY_SM2_CTRL_STR, ERR_R_PASSED_INVALID_ARGUMENT);
271 return 0;
272 }
273 ret = pkey_sm2_ctrl(ctx, EVP_PKEY_CTRL_SET1_ID, (int)hex_len,
274 (void *)hex_id);
275 OPENSSL_free(hex_id);
276 return ret;
277 }
278
279 return -2;
280}
281
282static int pkey_sm2_digest_custom(EVP_PKEY_CTX *ctx, EVP_MD_CTX *mctx)
283{
284 uint8_t z[EVP_MAX_MD_SIZE];
285 SM2_PKEY_CTX *smctx = ctx->data;
286 EC_KEY *ec = ctx->pkey->pkey.ec;
287 const EVP_MD *md = EVP_MD_CTX_md(mctx);
288 int mdlen = EVP_MD_size(md);
289
290 if (!smctx->id_set) {
291 /*
292 * An ID value must be set. The specifications are not clear whether a
293 * NULL is allowed. We only allow it if set explicitly for maximum
294 * flexibility.
295 */
296 SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_ID_NOT_SET);
297 return 0;
298 }
299
300 if (mdlen < 0) {
301 SM2err(SM2_F_PKEY_SM2_DIGEST_CUSTOM, SM2_R_INVALID_DIGEST);
302 return 0;
303 }
304
305 /* get hashed prefix 'z' of tbs message */
306 if (!sm2_compute_z_digest(z, md, smctx->id, smctx->id_len, ec))
307 return 0;
308
309 return EVP_DigestUpdate(mctx, z, (size_t)mdlen);
310}
311
312static const EVP_PKEY_METHOD sm2_pkey_meth = {
313 EVP_PKEY_SM2,
314 0,
315 pkey_sm2_init,
316 pkey_sm2_copy,
317 pkey_sm2_cleanup,
318
319 0,
320 0,
321
322 0,
323 0,
324
325 0,
326 pkey_sm2_sign,
327
328 0,
329 pkey_sm2_verify,
330
331 0, 0,
332
333 0, 0, 0, 0,
334
335 0,
336 pkey_sm2_encrypt,
337
338 0,
339 pkey_sm2_decrypt,
340
341 0,
342 0,
343 pkey_sm2_ctrl,
344 pkey_sm2_ctrl_str,
345
346 0, 0,
347
348 0, 0, 0,
349
350 pkey_sm2_digest_custom
351};
352
353const EVP_PKEY_METHOD *sm2_pkey_method(void)
354{
355 return &sm2_pkey_meth;
356}
357