/src/openssl30/crypto/sm2/sm2_sign.c

Source
/*
 * Copyright 2017-2025 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright 2017 Ribose Inc. All Rights Reserved.
 * Ported from Ribose contributions from Botan.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include "internal/deprecated.h"

#include "crypto/sm2.h"
#include "crypto/sm2err.h"
#include "crypto/ec.h" /* ossl_ec_group_do_inverse_ord() */
#include "internal/numbers.h"
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/bn.h>
#include <string.h>

int ossl_sm2_compute_z_digest(uint8_t *out,
    const EVP_MD *digest,
    const uint8_t *id,
    const size_t id_len,
    const EC_KEY *key)
{
    int rc = 0;
    const EC_GROUP *group = EC_KEY_get0_group(key);
    const EC_POINT *pubkey = EC_KEY_get0_public_key(key);
    BN_CTX *ctx = NULL;
    EVP_MD_CTX *hash = NULL;
    BIGNUM *p = NULL;
    BIGNUM *a = NULL;
    BIGNUM *b = NULL;
    BIGNUM *xG = NULL;
    BIGNUM *yG = NULL;
    BIGNUM *xA = NULL;
    BIGNUM *yA = NULL;
    int p_bytes = 0;
    uint8_t *buf = NULL;
    uint16_t entl = 0;
    uint8_t e_byte = 0;

    /* SM2 Signatures require a public key, check for it */
    if (pubkey == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
        goto done;
    }

    hash = EVP_MD_CTX_new();
    ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
    if (hash == NULL || ctx == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    BN_CTX_start(ctx);
    p = BN_CTX_get(ctx);
    a = BN_CTX_get(ctx);
    b = BN_CTX_get(ctx);
    xG = BN_CTX_get(ctx);
    yG = BN_CTX_get(ctx);
    xA = BN_CTX_get(ctx);
    yA = BN_CTX_get(ctx);

    if (yA == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    if (!EVP_DigestInit(hash, digest)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }

    /* Z = h(ENTL || ID || a || b || xG || yG || xA || yA) */

    if (id_len >= (UINT16_MAX / 8)) {
        /* too large */
        ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
        goto done;
    }

    entl = (uint16_t)(8 * id_len);

    e_byte = entl >> 8;
    if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }
    e_byte = entl & 0xFF;
    if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }

    if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }

    if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
        goto done;
    }

    p_bytes = BN_num_bytes(p);
    buf = OPENSSL_zalloc(p_bytes);
    if (buf == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    if (BN_bn2binpad(a, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || BN_bn2binpad(b, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || !EC_POINT_get_affine_coordinates(group,
            EC_GROUP_get0_generator(group),
            xG, yG, ctx)
        || BN_bn2binpad(xG, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || BN_bn2binpad(yG, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || !EC_POINT_get_affine_coordinates(group,
            pubkey,
            xA, yA, ctx)
        || BN_bn2binpad(xA, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || BN_bn2binpad(yA, buf, p_bytes) < 0
        || !EVP_DigestUpdate(hash, buf, p_bytes)
        || !EVP_DigestFinal(hash, out, NULL)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
        goto done;
    }

    rc = 1;

done:
    OPENSSL_free(buf);
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    EVP_MD_CTX_free(hash);
    return rc;
}

static BIGNUM *sm2_compute_msg_hash(const EVP_MD *digest,
    const EC_KEY *key,
    const uint8_t *id,
    const size_t id_len,
    const uint8_t *msg, size_t msg_len)
{
    EVP_MD_CTX *hash = EVP_MD_CTX_new();
    const int md_size = EVP_MD_get_size(digest);
    uint8_t *z = NULL;
    BIGNUM *e = NULL;
    EVP_MD *fetched_digest = NULL;
    OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
    const char *propq = ossl_ec_key_get0_propq(key);

    if (md_size < 0) {
        ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
        goto done;
    }

    z = OPENSSL_zalloc(md_size);
    if (hash == NULL || z == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
    if (fetched_digest == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
        goto done;
    }

    if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
        /* SM2err already called */
        goto done;
    }

    if (!EVP_DigestInit(hash, fetched_digest)
        || !EVP_DigestUpdate(hash, z, md_size)
        || !EVP_DigestUpdate(hash, msg, msg_len)
        /* reuse z buffer to hold H(Z || M) */
        || !EVP_DigestFinal(hash, z, NULL)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }

    e = BN_bin2bn(z, md_size, NULL);
    if (e == NULL)
        ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);

done:
    EVP_MD_free(fetched_digest);
    OPENSSL_free(z);
    EVP_MD_CTX_free(hash);
    return e;
}

static ECDSA_SIG *sm2_sig_gen(const EC_KEY *key, const BIGNUM *e)
{
    const BIGNUM *dA = EC_KEY_get0_private_key(key);
    const EC_GROUP *group = EC_KEY_get0_group(key);
    const BIGNUM *order = EC_GROUP_get0_order(group);
    ECDSA_SIG *sig = NULL;
    EC_POINT *kG = NULL;
    BN_CTX *ctx = NULL;
    BIGNUM *k = NULL;
    BIGNUM *rk = NULL;
    BIGNUM *r = NULL;
    BIGNUM *s = NULL;
    BIGNUM *x1 = NULL;
    BIGNUM *tmp = NULL;
    OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);

    if (dA == NULL) {
        ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_PRIVATE_KEY);
        goto done;
    }
    kG = EC_POINT_new(group);
    ctx = BN_CTX_new_ex(libctx);
    if (kG == NULL || ctx == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    BN_CTX_start(ctx);
    k = BN_CTX_get(ctx);
    rk = BN_CTX_get(ctx);
    x1 = BN_CTX_get(ctx);
    tmp = BN_CTX_get(ctx);
    if (tmp == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    /*
     * These values are returned and so should not be allocated out of the
     * context
     */
    r = BN_new();
    s = BN_new();

    if (r == NULL || s == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    /*
     * A3: Generate a random number k in [1,n-1] using random number generators;
     * A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
     *     as specified in clause 4.2.8 of GM/T 0003.1-2012;
     * A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
     * A6: Compute s=(1/(1+dA)*(k-r*dA)) mod n. If s=0, then go to A3;
     * A7: Convert the type of data (r,s) to be bit strings according to the details
     *     in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
     */
    for (;;) {
        if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
            ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
            goto done;
        }

        if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
            || !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
                ctx)
            || !BN_mod_add(r, e, x1, order, ctx)) {
            ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
            goto done;
        }

        /* try again if r == 0 or r+k == n */
        if (BN_is_zero(r))
            continue;

        if (!BN_add(rk, r, k)) {
            ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
            goto done;
        }

        if (BN_cmp(rk, order) == 0)
            continue;

        if (!BN_add(s, dA, BN_value_one())
            || !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
            || !BN_mod_mul(tmp, dA, r, order, ctx)
            || !BN_sub(tmp, k, tmp)
            || !BN_mod_mul(s, s, tmp, order, ctx)) {
            ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
            goto done;
        }

        /* try again if s == 0 */
        if (BN_is_zero(s))
            continue;

        sig = ECDSA_SIG_new();
        if (sig == NULL) {
            ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
            goto done;
        }

        /* takes ownership of r and s */
        ECDSA_SIG_set0(sig, r, s);
        break;
    }

done:
    if (sig == NULL) {
        BN_free(r);
        BN_free(s);
    }

    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    EC_POINT_free(kG);
    return sig;
}

static int sm2_sig_verify(const EC_KEY *key, const ECDSA_SIG *sig,
    const BIGNUM *e)
{
    int ret = 0;
    const EC_GROUP *group = EC_KEY_get0_group(key);
    const BIGNUM *order = EC_GROUP_get0_order(group);
    BN_CTX *ctx = NULL;
    EC_POINT *pt = NULL;
    BIGNUM *t = NULL;
    BIGNUM *x1 = NULL;
    const BIGNUM *r = NULL;
    const BIGNUM *s = NULL;
    OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);

    ctx = BN_CTX_new_ex(libctx);
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }
    BN_CTX_start(ctx);
    t = BN_CTX_get(ctx);
    x1 = BN_CTX_get(ctx);
    if (x1 == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    pt = EC_POINT_new(group);
    if (pt == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }

    /*
     * B1: verify whether r' in [1,n-1], verification failed if not
     * B2: verify whether s' in [1,n-1], verification failed if not
     * B3: set M'~=ZA || M'
     * B4: calculate e'=Hv(M'~)
     * B5: calculate t = (r' + s') modn, verification failed if t=0
     * B6: calculate the point (x1', y1')=[s']G + [t]PA
     * B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
     */

    ECDSA_SIG_get0(sig, &r, &s);

    if (BN_cmp(r, BN_value_one()) < 0
        || BN_cmp(s, BN_value_one()) < 0
        || BN_cmp(order, r) <= 0
        || BN_cmp(order, s) <= 0) {
        ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
        goto done;
    }

    if (!BN_mod_add(t, r, s, order, ctx)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        goto done;
    }

    if (BN_is_zero(t)) {
        ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
        goto done;
    }

    if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
        || !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
        goto done;
    }

    if (!BN_mod_add(t, e, x1, order, ctx)) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        goto done;
    }

    if (BN_cmp(r, t) == 0)
        ret = 1;

done:
    EC_POINT_free(pt);
    BN_CTX_end(ctx);
    BN_CTX_free(ctx);
    return ret;
}

ECDSA_SIG *ossl_sm2_do_sign(const EC_KEY *key,
    const EVP_MD *digest,
    const uint8_t *id,
    const size_t id_len,
    const uint8_t *msg, size_t msg_len)
{
    BIGNUM *e = NULL;
    ECDSA_SIG *sig = NULL;

    e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
    if (e == NULL) {
        /* SM2err already called */
        goto done;
    }

    sig = sm2_sig_gen(key, e);

done:
    BN_free(e);
    return sig;
}

int ossl_sm2_do_verify(const EC_KEY *key,
    const EVP_MD *digest,
    const ECDSA_SIG *sig,
    const uint8_t *id,
    const size_t id_len,
    const uint8_t *msg, size_t msg_len)
{
    BIGNUM *e = NULL;
    int ret = 0;

    e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
    if (e == NULL) {
        /* SM2err already called */
        goto done;
    }

    ret = sm2_sig_verify(key, sig, e);

done:
    BN_free(e);
    return ret;
}

int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
    unsigned char *sig, unsigned int *siglen,
    EC_KEY *eckey)
{
    BIGNUM *e = NULL;
    ECDSA_SIG *s = NULL;
    int sigleni;
    int ret = -1;

    if (sig == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
        goto done;
    }

    e = BN_bin2bn(dgst, dgstlen, NULL);
    if (e == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        goto done;
    }

    s = sm2_sig_gen(eckey, e);
    if (s == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
        goto done;
    }

    sigleni = i2d_ECDSA_SIG(s, &sig);
    if (sigleni < 0) {
        ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
        goto done;
    }
    *siglen = (unsigned int)sigleni;

    ret = 1;

done:
    ECDSA_SIG_free(s);
    BN_free(e);
    return ret;
}

int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
    const unsigned char *sig, int sig_len,
    EC_KEY *eckey)
{
    ECDSA_SIG *s = NULL;
    BIGNUM *e = NULL;
    const unsigned char *p = sig;
    unsigned char *der = NULL;
    int derlen = -1;
    int ret = -1;

    s = ECDSA_SIG_new();
    if (s == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
        goto done;
    }
    if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
        ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
        goto done;
    }
    /* Ensure signature uses DER and doesn't have trailing garbage */
    derlen = i2d_ECDSA_SIG(s, &der);
    if (derlen != sig_len || memcmp(sig, der, derlen) != 0) {
        ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
        goto done;
    }

    e = BN_bin2bn(dgst, dgstlen, NULL);
    if (e == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        goto done;
    }

    ret = sm2_sig_verify(eckey, s, e);

done:
    OPENSSL_free(der);
    BN_free(e);
    ECDSA_SIG_free(s);
    return ret;
}

Coverage Report

Created: 2026-05-24 07:14

Line	Count	Source
1		/*
2		* Copyright 2017-2025 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright 2017 Ribose Inc. All Rights Reserved.
4		* Ported from Ribose contributions from Botan.
5		*
6		* Licensed under the Apache License 2.0 (the "License"). You may not use
7		* this file except in compliance with the License. You can obtain a copy
8		* in the file LICENSE in the source distribution or at
9		* https://www.openssl.org/source/license.html
10		*/
11
12		#include "internal/deprecated.h"
13
14		#include "crypto/sm2.h"
15		#include "crypto/sm2err.h"
16		#include "crypto/ec.h" /* ossl_ec_group_do_inverse_ord() */
17		#include "internal/numbers.h"
18		#include <openssl/err.h>
19		#include <openssl/evp.h>
20		#include <openssl/err.h>
21		#include <openssl/bn.h>
22		#include <string.h>
23
24		int ossl_sm2_compute_z_digest(uint8_t *out,
25		const EVP_MD *digest,
26		const uint8_t *id,
27		const size_t id_len,
28		const EC_KEY *key)
29	0	{
30	0	int rc = 0;
31	0	const EC_GROUP *group = EC_KEY_get0_group(key);
32	0	const EC_POINT *pubkey = EC_KEY_get0_public_key(key);
33	0	BN_CTX *ctx = NULL;
34	0	EVP_MD_CTX *hash = NULL;
35	0	BIGNUM *p = NULL;
36	0	BIGNUM *a = NULL;
37	0	BIGNUM *b = NULL;
38	0	BIGNUM *xG = NULL;
39	0	BIGNUM *yG = NULL;
40	0	BIGNUM *xA = NULL;
41	0	BIGNUM *yA = NULL;
42	0	int p_bytes = 0;
43	0	uint8_t *buf = NULL;
44	0	uint16_t entl = 0;
45	0	uint8_t e_byte = 0;
46
47		/* SM2 Signatures require a public key, check for it */
48	0	if (pubkey == NULL) {
49	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
50	0	goto done;
51	0	}
52
53	0	hash = EVP_MD_CTX_new();
54	0	ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
55	0	if (hash == NULL \|\| ctx == NULL) {
56	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
57	0	goto done;
58	0	}
59
60	0	BN_CTX_start(ctx);
61	0	p = BN_CTX_get(ctx);
62	0	a = BN_CTX_get(ctx);
63	0	b = BN_CTX_get(ctx);
64	0	xG = BN_CTX_get(ctx);
65	0	yG = BN_CTX_get(ctx);
66	0	xA = BN_CTX_get(ctx);
67	0	yA = BN_CTX_get(ctx);
68
69	0	if (yA == NULL) {
70	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
71	0	goto done;
72	0	}
73
74	0	if (!EVP_DigestInit(hash, digest)) {
75	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
76	0	goto done;
77	0	}
78
79		/* Z = h(ENTL \|\| ID \|\| a \|\| b \|\| xG \|\| yG \|\| xA \|\| yA) */
80
81	0	if (id_len >= (UINT16_MAX / 8)) {
82		/* too large */
83	0	ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
84	0	goto done;
85	0	}
86
87	0	entl = (uint16_t)(8 * id_len);
88
89	0	e_byte = entl >> 8;
90	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
91	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
92	0	goto done;
93	0	}
94	0	e_byte = entl & 0xFF;
95	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
96	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
97	0	goto done;
98	0	}
99
100	0	if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
101	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
102	0	goto done;
103	0	}
104
105	0	if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
106	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
107	0	goto done;
108	0	}
109
110	0	p_bytes = BN_num_bytes(p);
111	0	buf = OPENSSL_zalloc(p_bytes);
112	0	if (buf == NULL) {
113	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
114	0	goto done;
115	0	}
116
117	0	if (BN_bn2binpad(a, buf, p_bytes) < 0
118	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
119	0	\|\| BN_bn2binpad(b, buf, p_bytes) < 0
120	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
121	0	\|\| !EC_POINT_get_affine_coordinates(group,
122	0	EC_GROUP_get0_generator(group),
123	0	xG, yG, ctx)
124	0	\|\| BN_bn2binpad(xG, buf, p_bytes) < 0
125	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
126	0	\|\| BN_bn2binpad(yG, buf, p_bytes) < 0
127	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
128	0	\|\| !EC_POINT_get_affine_coordinates(group,
129	0	pubkey,
130	0	xA, yA, ctx)
131	0	\|\| BN_bn2binpad(xA, buf, p_bytes) < 0
132	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
133	0	\|\| BN_bn2binpad(yA, buf, p_bytes) < 0
134	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
135	0	\|\| !EVP_DigestFinal(hash, out, NULL)) {
136	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
137	0	goto done;
138	0	}
139
140	0	rc = 1;
141
142	0	done:
143	0	OPENSSL_free(buf);
144	0	BN_CTX_end(ctx);
145	0	BN_CTX_free(ctx);
146	0	EVP_MD_CTX_free(hash);
147	0	return rc;
148	0	}
149
150		static BIGNUM sm2_compute_msg_hash(const EVP_MD digest,
151		const EC_KEY *key,
152		const uint8_t *id,
153		const size_t id_len,
154		const uint8_t *msg, size_t msg_len)
155	0	{
156	0	EVP_MD_CTX *hash = EVP_MD_CTX_new();
157	0	const int md_size = EVP_MD_get_size(digest);
158	0	uint8_t *z = NULL;
159	0	BIGNUM *e = NULL;
160	0	EVP_MD *fetched_digest = NULL;
161	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
162	0	const char *propq = ossl_ec_key_get0_propq(key);
163
164	0	if (md_size < 0) {
165	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
166	0	goto done;
167	0	}
168
169	0	z = OPENSSL_zalloc(md_size);
170	0	if (hash == NULL \|\| z == NULL) {
171	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
172	0	goto done;
173	0	}
174
175	0	fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
176	0	if (fetched_digest == NULL) {
177	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
178	0	goto done;
179	0	}
180
181	0	if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
182		/* SM2err already called */
183	0	goto done;
184	0	}
185
186	0	if (!EVP_DigestInit(hash, fetched_digest)
187	0	\|\| !EVP_DigestUpdate(hash, z, md_size)
188	0	\|\| !EVP_DigestUpdate(hash, msg, msg_len)
189		/* reuse z buffer to hold H(Z \|\| M) */
190	0	\|\| !EVP_DigestFinal(hash, z, NULL)) {
191	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
192	0	goto done;
193	0	}
194
195	0	e = BN_bin2bn(z, md_size, NULL);
196	0	if (e == NULL)
197	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
198
199	0	done:
200	0	EVP_MD_free(fetched_digest);
201	0	OPENSSL_free(z);
202	0	EVP_MD_CTX_free(hash);
203	0	return e;
204	0	}
205
206		static ECDSA_SIG sm2_sig_gen(const EC_KEY key, const BIGNUM *e)
207	0	{
208	0	const BIGNUM *dA = EC_KEY_get0_private_key(key);
209	0	const EC_GROUP *group = EC_KEY_get0_group(key);
210	0	const BIGNUM *order = EC_GROUP_get0_order(group);
211	0	ECDSA_SIG *sig = NULL;
212	0	EC_POINT *kG = NULL;
213	0	BN_CTX *ctx = NULL;
214	0	BIGNUM *k = NULL;
215	0	BIGNUM *rk = NULL;
216	0	BIGNUM *r = NULL;
217	0	BIGNUM *s = NULL;
218	0	BIGNUM *x1 = NULL;
219	0	BIGNUM *tmp = NULL;
220	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
221
222	0	if (dA == NULL) {
223	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_PRIVATE_KEY);
224	0	goto done;
225	0	}
226	0	kG = EC_POINT_new(group);
227	0	ctx = BN_CTX_new_ex(libctx);
228	0	if (kG == NULL \|\| ctx == NULL) {
229	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
230	0	goto done;
231	0	}
232
233	0	BN_CTX_start(ctx);
234	0	k = BN_CTX_get(ctx);
235	0	rk = BN_CTX_get(ctx);
236	0	x1 = BN_CTX_get(ctx);
237	0	tmp = BN_CTX_get(ctx);
238	0	if (tmp == NULL) {
239	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
240	0	goto done;
241	0	}
242
243		/*
244		* These values are returned and so should not be allocated out of the
245		* context
246		*/
247	0	r = BN_new();
248	0	s = BN_new();
249
250	0	if (r == NULL \|\| s == NULL) {
251	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
252	0	goto done;
253	0	}
254
255		/*
256		* A3: Generate a random number k in [1,n-1] using random number generators;
257		* A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
258		* as specified in clause 4.2.8 of GM/T 0003.1-2012;
259		* A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
260		* A6: Compute s=(1/(1+dA)(k-rdA)) mod n. If s=0, then go to A3;
261		* A7: Convert the type of data (r,s) to be bit strings according to the details
262		* in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
263		*/
264	0	for (;;) {
265	0	if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
266	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
267	0	goto done;
268	0	}
269
270	0	if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
271	0	\|\| !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
272	0	ctx)
273	0	\|\| !BN_mod_add(r, e, x1, order, ctx)) {
274	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
275	0	goto done;
276	0	}
277
278		/* try again if r == 0 or r+k == n */
279	0	if (BN_is_zero(r))
280	0	continue;
281
282	0	if (!BN_add(rk, r, k)) {
283	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
284	0	goto done;
285	0	}
286
287	0	if (BN_cmp(rk, order) == 0)
288	0	continue;
289
290	0	if (!BN_add(s, dA, BN_value_one())
291	0	\|\| !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
292	0	\|\| !BN_mod_mul(tmp, dA, r, order, ctx)
293	0	\|\| !BN_sub(tmp, k, tmp)
294	0	\|\| !BN_mod_mul(s, s, tmp, order, ctx)) {
295	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
296	0	goto done;
297	0	}
298
299		/* try again if s == 0 */
300	0	if (BN_is_zero(s))
301	0	continue;
302
303	0	sig = ECDSA_SIG_new();
304	0	if (sig == NULL) {
305	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
306	0	goto done;
307	0	}
308
309		/* takes ownership of r and s */
310	0	ECDSA_SIG_set0(sig, r, s);
311	0	break;
312	0	}
313
314	0	done:
315	0	if (sig == NULL) {
316	0	BN_free(r);
317	0	BN_free(s);
318	0	}
319
320	0	BN_CTX_end(ctx);
321	0	BN_CTX_free(ctx);
322	0	EC_POINT_free(kG);
323	0	return sig;
324	0	}
325
326		static int sm2_sig_verify(const EC_KEY key, const ECDSA_SIG sig,
327		const BIGNUM *e)
328	0	{
329	0	int ret = 0;
330	0	const EC_GROUP *group = EC_KEY_get0_group(key);
331	0	const BIGNUM *order = EC_GROUP_get0_order(group);
332	0	BN_CTX *ctx = NULL;
333	0	EC_POINT *pt = NULL;
334	0	BIGNUM *t = NULL;
335	0	BIGNUM *x1 = NULL;
336	0	const BIGNUM *r = NULL;
337	0	const BIGNUM *s = NULL;
338	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
339
340	0	ctx = BN_CTX_new_ex(libctx);
341	0	if (ctx == NULL) {
342	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
343	0	goto done;
344	0	}
345	0	BN_CTX_start(ctx);
346	0	t = BN_CTX_get(ctx);
347	0	x1 = BN_CTX_get(ctx);
348	0	if (x1 == NULL) {
349	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
350	0	goto done;
351	0	}
352
353	0	pt = EC_POINT_new(group);
354	0	if (pt == NULL) {
355	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
356	0	goto done;
357	0	}
358
359		/*
360		* B1: verify whether r' in [1,n-1], verification failed if not
361		* B2: verify whether s' in [1,n-1], verification failed if not
362		* B3: set M'~=ZA \|\| M'
363		* B4: calculate e'=Hv(M'~)
364		* B5: calculate t = (r' + s') modn, verification failed if t=0
365		* B6: calculate the point (x1', y1')=[s']G + [t]PA
366		* B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
367		*/
368
369	0	ECDSA_SIG_get0(sig, &r, &s);
370
371	0	if (BN_cmp(r, BN_value_one()) < 0
372	0	\|\| BN_cmp(s, BN_value_one()) < 0
373	0	\|\| BN_cmp(order, r) <= 0
374	0	\|\| BN_cmp(order, s) <= 0) {
375	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
376	0	goto done;
377	0	}
378
379	0	if (!BN_mod_add(t, r, s, order, ctx)) {
380	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
381	0	goto done;
382	0	}
383
384	0	if (BN_is_zero(t)) {
385	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
386	0	goto done;
387	0	}
388
389	0	if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
390	0	\|\| !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
391	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
392	0	goto done;
393	0	}
394
395	0	if (!BN_mod_add(t, e, x1, order, ctx)) {
396	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
397	0	goto done;
398	0	}
399
400	0	if (BN_cmp(r, t) == 0)
401	0	ret = 1;
402
403	0	done:
404	0	EC_POINT_free(pt);
405	0	BN_CTX_end(ctx);
406	0	BN_CTX_free(ctx);
407	0	return ret;
408	0	}
409
410		ECDSA_SIG ossl_sm2_do_sign(const EC_KEY key,
411		const EVP_MD *digest,
412		const uint8_t *id,
413		const size_t id_len,
414		const uint8_t *msg, size_t msg_len)
415	0	{
416	0	BIGNUM *e = NULL;
417	0	ECDSA_SIG *sig = NULL;
418
419	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
420	0	if (e == NULL) {
421		/* SM2err already called */
422	0	goto done;
423	0	}
424
425	0	sig = sm2_sig_gen(key, e);
426
427	0	done:
428	0	BN_free(e);
429	0	return sig;
430	0	}
431
432		int ossl_sm2_do_verify(const EC_KEY *key,
433		const EVP_MD *digest,
434		const ECDSA_SIG *sig,
435		const uint8_t *id,
436		const size_t id_len,
437		const uint8_t *msg, size_t msg_len)
438	0	{
439	0	BIGNUM *e = NULL;
440	0	int ret = 0;
441
442	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
443	0	if (e == NULL) {
444		/* SM2err already called */
445	0	goto done;
446	0	}
447
448	0	ret = sm2_sig_verify(key, sig, e);
449
450	0	done:
451	0	BN_free(e);
452	0	return ret;
453	0	}
454
455		int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
456		unsigned char sig, unsigned int siglen,
457		EC_KEY *eckey)
458	0	{
459	0	BIGNUM *e = NULL;
460	0	ECDSA_SIG *s = NULL;
461	0	int sigleni;
462	0	int ret = -1;
463
464	0	if (sig == NULL) {
465	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
466	0	goto done;
467	0	}
468
469	0	e = BN_bin2bn(dgst, dgstlen, NULL);
470	0	if (e == NULL) {
471	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
472	0	goto done;
473	0	}
474
475	0	s = sm2_sig_gen(eckey, e);
476	0	if (s == NULL) {
477	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
478	0	goto done;
479	0	}
480
481	0	sigleni = i2d_ECDSA_SIG(s, &sig);
482	0	if (sigleni < 0) {
483	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
484	0	goto done;
485	0	}
486	0	*siglen = (unsigned int)sigleni;
487
488	0	ret = 1;
489
490	0	done:
491	0	ECDSA_SIG_free(s);
492	0	BN_free(e);
493	0	return ret;
494	0	}
495
496		int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
497		const unsigned char *sig, int sig_len,
498		EC_KEY *eckey)
499	0	{
500	0	ECDSA_SIG *s = NULL;
501	0	BIGNUM *e = NULL;
502	0	const unsigned char *p = sig;
503	0	unsigned char *der = NULL;
504	0	int derlen = -1;
505	0	int ret = -1;
506
507	0	s = ECDSA_SIG_new();
508	0	if (s == NULL) {
509	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
510	0	goto done;
511	0	}
512	0	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
513	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
514	0	goto done;
515	0	}
516		/* Ensure signature uses DER and doesn't have trailing garbage */
517	0	derlen = i2d_ECDSA_SIG(s, &der);
518	0	if (derlen != sig_len \|\| memcmp(sig, der, derlen) != 0) {
519	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
520	0	goto done;
521	0	}
522
523	0	e = BN_bin2bn(dgst, dgstlen, NULL);
524	0	if (e == NULL) {
525	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
526	0	goto done;
527	0	}
528
529	0	ret = sm2_sig_verify(eckey, s, e);
530
531	0	done:
532	0	OPENSSL_free(der);
533	0	BN_free(e);
534	0	ECDSA_SIG_free(s);
535	0	return ret;
536	0	}