xref: /freebsd/crypto/openssl/providers/implementations/signature/sm2_sig.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*
2  * Copyright 2020-2022 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 /*
11  * ECDSA low level APIs are deprecated for public use, but still ok for
12  * internal use - SM2 implemetation uses ECDSA_size() function.
13  */
14 #include "internal/deprecated.h"
15 
16 #include <string.h> /* memcpy */
17 #include <openssl/crypto.h>
18 #include <openssl/core_dispatch.h>
19 #include <openssl/core_names.h>
20 #include <openssl/dsa.h>
21 #include <openssl/params.h>
22 #include <openssl/evp.h>
23 #include <openssl/err.h>
24 #include <openssl/proverr.h>
25 #include "internal/nelem.h"
26 #include "internal/sizes.h"
27 #include "internal/cryptlib.h"
28 #include "internal/sm3.h"
29 #include "prov/implementations.h"
30 #include "prov/providercommon.h"
31 #include "prov/provider_ctx.h"
32 #include "crypto/ec.h"
33 #include "crypto/sm2.h"
34 #include "prov/der_sm2.h"
35 
36 static OSSL_FUNC_signature_newctx_fn sm2sig_newctx;
37 static OSSL_FUNC_signature_sign_init_fn sm2sig_signature_init;
38 static OSSL_FUNC_signature_verify_init_fn sm2sig_signature_init;
39 static OSSL_FUNC_signature_sign_fn sm2sig_sign;
40 static OSSL_FUNC_signature_verify_fn sm2sig_verify;
41 static OSSL_FUNC_signature_digest_sign_init_fn sm2sig_digest_signverify_init;
42 static OSSL_FUNC_signature_digest_sign_update_fn sm2sig_digest_signverify_update;
43 static OSSL_FUNC_signature_digest_sign_final_fn sm2sig_digest_sign_final;
44 static OSSL_FUNC_signature_digest_verify_init_fn sm2sig_digest_signverify_init;
45 static OSSL_FUNC_signature_digest_verify_update_fn sm2sig_digest_signverify_update;
46 static OSSL_FUNC_signature_digest_verify_final_fn sm2sig_digest_verify_final;
47 static OSSL_FUNC_signature_freectx_fn sm2sig_freectx;
48 static OSSL_FUNC_signature_dupctx_fn sm2sig_dupctx;
49 static OSSL_FUNC_signature_get_ctx_params_fn sm2sig_get_ctx_params;
50 static OSSL_FUNC_signature_gettable_ctx_params_fn sm2sig_gettable_ctx_params;
51 static OSSL_FUNC_signature_set_ctx_params_fn sm2sig_set_ctx_params;
52 static OSSL_FUNC_signature_settable_ctx_params_fn sm2sig_settable_ctx_params;
53 static OSSL_FUNC_signature_get_ctx_md_params_fn sm2sig_get_ctx_md_params;
54 static OSSL_FUNC_signature_gettable_ctx_md_params_fn sm2sig_gettable_ctx_md_params;
55 static OSSL_FUNC_signature_set_ctx_md_params_fn sm2sig_set_ctx_md_params;
56 static OSSL_FUNC_signature_settable_ctx_md_params_fn sm2sig_settable_ctx_md_params;
57 
58 /*
59  * What's passed as an actual key is defined by the KEYMGMT interface.
60  * We happen to know that our KEYMGMT simply passes EC structures, so
61  * we use that here too.
62  */
63 typedef struct {
64     OSSL_LIB_CTX *libctx;
65     char *propq;
66     EC_KEY *ec;
67 
68     /*
69      * Flag to termine if the 'z' digest needs to be computed and fed to the
70      * hash function.
71      * This flag should be set on initialization and the compuation should
72      * be performed only once, on first update.
73      */
74     unsigned int flag_compute_z_digest : 1;
75 
76     char mdname[OSSL_MAX_NAME_SIZE];
77 
78     /* The Algorithm Identifier of the combined signature algorithm */
79     unsigned char aid_buf[OSSL_MAX_ALGORITHM_ID_SIZE];
80     unsigned char *aid;
81     size_t  aid_len;
82 
83     /* main digest */
84     EVP_MD *md;
85     EVP_MD_CTX *mdctx;
86     size_t mdsize;
87 
88     /* SM2 ID used for calculating the Z value */
89     unsigned char *id;
90     size_t id_len;
91 } PROV_SM2_CTX;
92 
93 static int sm2sig_set_mdname(PROV_SM2_CTX *psm2ctx, const char *mdname)
94 {
95     if (psm2ctx->md == NULL) /* We need an SM3 md to compare with */
96         psm2ctx->md = EVP_MD_fetch(psm2ctx->libctx, psm2ctx->mdname,
97                                    psm2ctx->propq);
98     if (psm2ctx->md == NULL)
99         return 0;
100 
101     if (mdname == NULL)
102         return 1;
103 
104     if (strlen(mdname) >= sizeof(psm2ctx->mdname)
105         || !EVP_MD_is_a(psm2ctx->md, mdname)) {
106         ERR_raise_data(ERR_LIB_PROV, PROV_R_INVALID_DIGEST, "digest=%s",
107                        mdname);
108         return 0;
109     }
110 
111     OPENSSL_strlcpy(psm2ctx->mdname, mdname, sizeof(psm2ctx->mdname));
112     return 1;
113 }
114 
115 static void *sm2sig_newctx(void *provctx, const char *propq)
116 {
117     PROV_SM2_CTX *ctx = OPENSSL_zalloc(sizeof(PROV_SM2_CTX));
118 
119     if (ctx == NULL)
120         return NULL;
121 
122     ctx->libctx = PROV_LIBCTX_OF(provctx);
123     if (propq != NULL && (ctx->propq = OPENSSL_strdup(propq)) == NULL) {
124         OPENSSL_free(ctx);
125         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
126         return NULL;
127     }
128     ctx->mdsize = SM3_DIGEST_LENGTH;
129     strcpy(ctx->mdname, OSSL_DIGEST_NAME_SM3);
130     return ctx;
131 }
132 
133 static int sm2sig_signature_init(void *vpsm2ctx, void *ec,
134                                  const OSSL_PARAM params[])
135 {
136     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
137 
138     if (!ossl_prov_is_running()
139             || psm2ctx == NULL)
140         return 0;
141 
142     if (ec == NULL && psm2ctx->ec == NULL) {
143         ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
144         return 0;
145     }
146 
147     if (ec != NULL) {
148         if (!EC_KEY_up_ref(ec))
149             return 0;
150         EC_KEY_free(psm2ctx->ec);
151         psm2ctx->ec = ec;
152     }
153 
154     return sm2sig_set_ctx_params(psm2ctx, params);
155 }
156 
157 static int sm2sig_sign(void *vpsm2ctx, unsigned char *sig, size_t *siglen,
158                        size_t sigsize, const unsigned char *tbs, size_t tbslen)
159 {
160     PROV_SM2_CTX *ctx = (PROV_SM2_CTX *)vpsm2ctx;
161     int ret;
162     unsigned int sltmp;
163     /* SM2 uses ECDSA_size as well */
164     size_t ecsize = ECDSA_size(ctx->ec);
165 
166     if (sig == NULL) {
167         *siglen = ecsize;
168         return 1;
169     }
170 
171     if (sigsize < (size_t)ecsize)
172         return 0;
173 
174     if (ctx->mdsize != 0 && tbslen != ctx->mdsize)
175         return 0;
176 
177     ret = ossl_sm2_internal_sign(tbs, tbslen, sig, &sltmp, ctx->ec);
178     if (ret <= 0)
179         return 0;
180 
181     *siglen = sltmp;
182     return 1;
183 }
184 
185 static int sm2sig_verify(void *vpsm2ctx, const unsigned char *sig, size_t siglen,
186                          const unsigned char *tbs, size_t tbslen)
187 {
188     PROV_SM2_CTX *ctx = (PROV_SM2_CTX *)vpsm2ctx;
189 
190     if (ctx->mdsize != 0 && tbslen != ctx->mdsize)
191         return 0;
192 
193     return ossl_sm2_internal_verify(tbs, tbslen, sig, siglen, ctx->ec);
194 }
195 
196 static void free_md(PROV_SM2_CTX *ctx)
197 {
198     EVP_MD_CTX_free(ctx->mdctx);
199     EVP_MD_free(ctx->md);
200     ctx->mdctx = NULL;
201     ctx->md = NULL;
202 }
203 
204 static int sm2sig_digest_signverify_init(void *vpsm2ctx, const char *mdname,
205                                          void *ec, const OSSL_PARAM params[])
206 {
207     PROV_SM2_CTX *ctx = (PROV_SM2_CTX *)vpsm2ctx;
208     int md_nid;
209     WPACKET pkt;
210     int ret = 0;
211 
212     if (!sm2sig_signature_init(vpsm2ctx, ec, params)
213         || !sm2sig_set_mdname(ctx, mdname))
214         return ret;
215 
216     if (ctx->mdctx == NULL) {
217         ctx->mdctx = EVP_MD_CTX_new();
218         if (ctx->mdctx == NULL)
219             goto error;
220     }
221 
222     md_nid = EVP_MD_get_type(ctx->md);
223 
224     /*
225      * We do not care about DER writing errors.
226      * All it really means is that for some reason, there's no
227      * AlgorithmIdentifier to be had, but the operation itself is
228      * still valid, just as long as it's not used to construct
229      * anything that needs an AlgorithmIdentifier.
230      */
231     ctx->aid_len = 0;
232     if (WPACKET_init_der(&pkt, ctx->aid_buf, sizeof(ctx->aid_buf))
233         && ossl_DER_w_algorithmIdentifier_SM2_with_MD(&pkt, -1, ctx->ec, md_nid)
234         && WPACKET_finish(&pkt)) {
235         WPACKET_get_total_written(&pkt, &ctx->aid_len);
236         ctx->aid = WPACKET_get_curr(&pkt);
237     }
238     WPACKET_cleanup(&pkt);
239 
240     if (!EVP_DigestInit_ex2(ctx->mdctx, ctx->md, params))
241         goto error;
242 
243     ctx->flag_compute_z_digest = 1;
244 
245     ret = 1;
246 
247  error:
248     return ret;
249 }
250 
251 static int sm2sig_compute_z_digest(PROV_SM2_CTX *ctx)
252 {
253     uint8_t *z = NULL;
254     int ret = 1;
255 
256     if (ctx->flag_compute_z_digest) {
257         /* Only do this once */
258         ctx->flag_compute_z_digest = 0;
259 
260         if ((z = OPENSSL_zalloc(ctx->mdsize)) == NULL
261             /* get hashed prefix 'z' of tbs message */
262             || !ossl_sm2_compute_z_digest(z, ctx->md, ctx->id, ctx->id_len,
263                                           ctx->ec)
264             || !EVP_DigestUpdate(ctx->mdctx, z, ctx->mdsize))
265             ret = 0;
266         OPENSSL_free(z);
267     }
268 
269     return ret;
270 }
271 
272 int sm2sig_digest_signverify_update(void *vpsm2ctx, const unsigned char *data,
273                                     size_t datalen)
274 {
275     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
276 
277     if (psm2ctx == NULL || psm2ctx->mdctx == NULL)
278         return 0;
279 
280     return sm2sig_compute_z_digest(psm2ctx)
281         && EVP_DigestUpdate(psm2ctx->mdctx, data, datalen);
282 }
283 
284 int sm2sig_digest_sign_final(void *vpsm2ctx, unsigned char *sig, size_t *siglen,
285                              size_t sigsize)
286 {
287     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
288     unsigned char digest[EVP_MAX_MD_SIZE];
289     unsigned int dlen = 0;
290 
291     if (psm2ctx == NULL || psm2ctx->mdctx == NULL)
292         return 0;
293 
294     /*
295      * If sig is NULL then we're just finding out the sig size. Other fields
296      * are ignored. Defer to sm2sig_sign.
297      */
298     if (sig != NULL) {
299         if (!(sm2sig_compute_z_digest(psm2ctx)
300               && EVP_DigestFinal_ex(psm2ctx->mdctx, digest, &dlen)))
301             return 0;
302     }
303 
304     return sm2sig_sign(vpsm2ctx, sig, siglen, sigsize, digest, (size_t)dlen);
305 }
306 
307 
308 int sm2sig_digest_verify_final(void *vpsm2ctx, const unsigned char *sig,
309                                size_t siglen)
310 {
311     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
312     unsigned char digest[EVP_MAX_MD_SIZE];
313     unsigned int dlen = 0;
314 
315     if (psm2ctx == NULL
316         || psm2ctx->mdctx == NULL
317         || EVP_MD_get_size(psm2ctx->md) > (int)sizeof(digest))
318         return 0;
319 
320     if (!(sm2sig_compute_z_digest(psm2ctx)
321           && EVP_DigestFinal_ex(psm2ctx->mdctx, digest, &dlen)))
322         return 0;
323 
324     return sm2sig_verify(vpsm2ctx, sig, siglen, digest, (size_t)dlen);
325 }
326 
327 static void sm2sig_freectx(void *vpsm2ctx)
328 {
329     PROV_SM2_CTX *ctx = (PROV_SM2_CTX *)vpsm2ctx;
330 
331     free_md(ctx);
332     EC_KEY_free(ctx->ec);
333     OPENSSL_free(ctx->id);
334     OPENSSL_free(ctx);
335 }
336 
337 static void *sm2sig_dupctx(void *vpsm2ctx)
338 {
339     PROV_SM2_CTX *srcctx = (PROV_SM2_CTX *)vpsm2ctx;
340     PROV_SM2_CTX *dstctx;
341 
342     dstctx = OPENSSL_zalloc(sizeof(*srcctx));
343     if (dstctx == NULL)
344         return NULL;
345 
346     *dstctx = *srcctx;
347     dstctx->ec = NULL;
348     dstctx->md = NULL;
349     dstctx->mdctx = NULL;
350 
351     if (srcctx->ec != NULL && !EC_KEY_up_ref(srcctx->ec))
352         goto err;
353     dstctx->ec = srcctx->ec;
354 
355     if (srcctx->md != NULL && !EVP_MD_up_ref(srcctx->md))
356         goto err;
357     dstctx->md = srcctx->md;
358 
359     if (srcctx->mdctx != NULL) {
360         dstctx->mdctx = EVP_MD_CTX_new();
361         if (dstctx->mdctx == NULL
362                 || !EVP_MD_CTX_copy_ex(dstctx->mdctx, srcctx->mdctx))
363             goto err;
364     }
365 
366     if (srcctx->id != NULL) {
367         dstctx->id = OPENSSL_malloc(srcctx->id_len);
368         if (dstctx->id == NULL)
369             goto err;
370         dstctx->id_len = srcctx->id_len;
371         memcpy(dstctx->id, srcctx->id, srcctx->id_len);
372     }
373 
374     return dstctx;
375  err:
376     sm2sig_freectx(dstctx);
377     return NULL;
378 }
379 
380 static int sm2sig_get_ctx_params(void *vpsm2ctx, OSSL_PARAM *params)
381 {
382     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
383     OSSL_PARAM *p;
384 
385     if (psm2ctx == NULL)
386         return 0;
387 
388     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_ALGORITHM_ID);
389     if (p != NULL
390         && !OSSL_PARAM_set_octet_string(p, psm2ctx->aid, psm2ctx->aid_len))
391         return 0;
392 
393     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST_SIZE);
394     if (p != NULL && !OSSL_PARAM_set_size_t(p, psm2ctx->mdsize))
395         return 0;
396 
397     p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST);
398     if (p != NULL && !OSSL_PARAM_set_utf8_string(p, psm2ctx->md == NULL
399                                                     ? psm2ctx->mdname
400                                                     : EVP_MD_get0_name(psm2ctx->md)))
401         return 0;
402 
403     return 1;
404 }
405 
406 static const OSSL_PARAM known_gettable_ctx_params[] = {
407     OSSL_PARAM_octet_string(OSSL_SIGNATURE_PARAM_ALGORITHM_ID, NULL, 0),
408     OSSL_PARAM_size_t(OSSL_SIGNATURE_PARAM_DIGEST_SIZE, NULL),
409     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
410     OSSL_PARAM_END
411 };
412 
413 static const OSSL_PARAM *sm2sig_gettable_ctx_params(ossl_unused void *vpsm2ctx,
414                                                     ossl_unused void *provctx)
415 {
416     return known_gettable_ctx_params;
417 }
418 
419 static int sm2sig_set_ctx_params(void *vpsm2ctx, const OSSL_PARAM params[])
420 {
421     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
422     const OSSL_PARAM *p;
423     size_t mdsize;
424 
425     if (psm2ctx == NULL)
426         return 0;
427     if (params == NULL)
428         return 1;
429 
430     p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_DIST_ID);
431     if (p != NULL) {
432         void *tmp_id = NULL;
433         size_t tmp_idlen = 0;
434 
435         /*
436          * If the 'z' digest has already been computed, the ID is set too late
437          */
438         if (!psm2ctx->flag_compute_z_digest)
439             return 0;
440 
441         if (p->data_size != 0
442             && !OSSL_PARAM_get_octet_string(p, &tmp_id, 0, &tmp_idlen))
443             return 0;
444         OPENSSL_free(psm2ctx->id);
445         psm2ctx->id = tmp_id;
446         psm2ctx->id_len = tmp_idlen;
447     }
448 
449     /*
450      * The following code checks that the size is the same as the SM3 digest
451      * size returning an error otherwise.
452      * If there is ever any different digest algorithm allowed with SM2
453      * this needs to be adjusted accordingly.
454      */
455     p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST_SIZE);
456     if (p != NULL && (!OSSL_PARAM_get_size_t(p, &mdsize)
457                       || mdsize != psm2ctx->mdsize))
458         return 0;
459 
460     p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST);
461     if (p != NULL) {
462         char *mdname = NULL;
463 
464         if (!OSSL_PARAM_get_utf8_string(p, &mdname, 0))
465             return 0;
466         if (!sm2sig_set_mdname(psm2ctx, mdname)) {
467             OPENSSL_free(mdname);
468             return 0;
469         }
470         OPENSSL_free(mdname);
471     }
472 
473     return 1;
474 }
475 
476 static const OSSL_PARAM known_settable_ctx_params[] = {
477     OSSL_PARAM_size_t(OSSL_SIGNATURE_PARAM_DIGEST_SIZE, NULL),
478     OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),
479     OSSL_PARAM_octet_string(OSSL_PKEY_PARAM_DIST_ID, NULL, 0),
480     OSSL_PARAM_END
481 };
482 
483 static const OSSL_PARAM *sm2sig_settable_ctx_params(ossl_unused void *vpsm2ctx,
484                                                     ossl_unused void *provctx)
485 {
486     return known_settable_ctx_params;
487 }
488 
489 static int sm2sig_get_ctx_md_params(void *vpsm2ctx, OSSL_PARAM *params)
490 {
491     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
492 
493     if (psm2ctx->mdctx == NULL)
494         return 0;
495 
496     return EVP_MD_CTX_get_params(psm2ctx->mdctx, params);
497 }
498 
499 static const OSSL_PARAM *sm2sig_gettable_ctx_md_params(void *vpsm2ctx)
500 {
501     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
502 
503     if (psm2ctx->md == NULL)
504         return 0;
505 
506     return EVP_MD_gettable_ctx_params(psm2ctx->md);
507 }
508 
509 static int sm2sig_set_ctx_md_params(void *vpsm2ctx, const OSSL_PARAM params[])
510 {
511     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
512 
513     if (psm2ctx->mdctx == NULL)
514         return 0;
515 
516     return EVP_MD_CTX_set_params(psm2ctx->mdctx, params);
517 }
518 
519 static const OSSL_PARAM *sm2sig_settable_ctx_md_params(void *vpsm2ctx)
520 {
521     PROV_SM2_CTX *psm2ctx = (PROV_SM2_CTX *)vpsm2ctx;
522 
523     if (psm2ctx->md == NULL)
524         return 0;
525 
526     return EVP_MD_settable_ctx_params(psm2ctx->md);
527 }
528 
529 const OSSL_DISPATCH ossl_sm2_signature_functions[] = {
530     { OSSL_FUNC_SIGNATURE_NEWCTX, (void (*)(void))sm2sig_newctx },
531     { OSSL_FUNC_SIGNATURE_SIGN_INIT, (void (*)(void))sm2sig_signature_init },
532     { OSSL_FUNC_SIGNATURE_SIGN, (void (*)(void))sm2sig_sign },
533     { OSSL_FUNC_SIGNATURE_VERIFY_INIT, (void (*)(void))sm2sig_signature_init },
534     { OSSL_FUNC_SIGNATURE_VERIFY, (void (*)(void))sm2sig_verify },
535     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT,
536       (void (*)(void))sm2sig_digest_signverify_init },
537     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE,
538       (void (*)(void))sm2sig_digest_signverify_update },
539     { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL,
540       (void (*)(void))sm2sig_digest_sign_final },
541     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT,
542       (void (*)(void))sm2sig_digest_signverify_init },
543     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE,
544       (void (*)(void))sm2sig_digest_signverify_update },
545     { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL,
546       (void (*)(void))sm2sig_digest_verify_final },
547     { OSSL_FUNC_SIGNATURE_FREECTX, (void (*)(void))sm2sig_freectx },
548     { OSSL_FUNC_SIGNATURE_DUPCTX, (void (*)(void))sm2sig_dupctx },
549     { OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS, (void (*)(void))sm2sig_get_ctx_params },
550     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS,
551       (void (*)(void))sm2sig_gettable_ctx_params },
552     { OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS, (void (*)(void))sm2sig_set_ctx_params },
553     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS,
554       (void (*)(void))sm2sig_settable_ctx_params },
555     { OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS,
556       (void (*)(void))sm2sig_get_ctx_md_params },
557     { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS,
558       (void (*)(void))sm2sig_gettable_ctx_md_params },
559     { OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS,
560       (void (*)(void))sm2sig_set_ctx_md_params },
561     { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS,
562       (void (*)(void))sm2sig_settable_ctx_md_params },
563     { 0, NULL }
564 };
565