/src/openssl/crypto/sm2/sm2_sign.c

Source
/*
 * Copyright 2017-2026 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/bn.h>
#include <string.h>

/*
 * [SM2 Signature Scheme]
 * (https://datatracker.ietf.org/doc/html/rfc8998#section-3.2.1)
 *
 * If either a client or a server needs to verify the peer's SM2 certificate
 * contained in the Certificate message, then the following ASCII string value
 * MUST be used as the SM2 identifier according to [GMT.0009-2012]:
 *
 * 1234567812345678
 */
static const uint8_t default_sm2_id[] = {
    0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
    0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38
};

int ossl_sm2_compute_z_digest(uint8_t *out,
    const EVP_MD *digest,
    const uint8_t *id,
    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();
    if (hash == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }
    ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        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_BN_LIB);
        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 == NULL) {
        id = default_sm2_id;
        id_len = sizeof(default_sm2_id);
    }

    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)
        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;
    }
    if (hash == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
        goto done;
    }

    z = OPENSSL_zalloc(md_size);
    if (z == NULL)
        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);
    if (kG == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
        goto done;
    }
    ctx = BN_CTX_new_ex(libctx);
    if (ctx == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
        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_BN_LIB);
        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_BN_LIB);
        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_ECDSA_LIB);
            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_BN_LIB);
        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_BN_LIB);
        goto done;
    }

    pt = EC_POINT_new(group);
    if (pt == NULL) {
        ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
        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_ECDSA_LIB);
        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: 2026-05-20 07:05

Line	Count	Source
1		/*
2		* Copyright 2017-2026 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/bn.h>
21		#include <string.h>
22
23		/*
24		* [SM2 Signature Scheme]
25		* (https://datatracker.ietf.org/doc/html/rfc8998#section-3.2.1)
26		*
27		* If either a client or a server needs to verify the peer's SM2 certificate
28		* contained in the Certificate message, then the following ASCII string value
29		* MUST be used as the SM2 identifier according to [GMT.0009-2012]:
30		*
31		* 1234567812345678
32		*/
33		static const uint8_t default_sm2_id[] = {
34		0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
35		0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38
36		};
37
38		int ossl_sm2_compute_z_digest(uint8_t *out,
39		const EVP_MD *digest,
40		const uint8_t *id,
41		size_t id_len,
42		const EC_KEY *key)
43	0	{
44	0	int rc = 0;
45	0	const EC_GROUP *group = EC_KEY_get0_group(key);
46	0	const EC_POINT *pubkey = EC_KEY_get0_public_key(key);
47	0	BN_CTX *ctx = NULL;
48	0	EVP_MD_CTX *hash = NULL;
49	0	BIGNUM *p = NULL;
50	0	BIGNUM *a = NULL;
51	0	BIGNUM *b = NULL;
52	0	BIGNUM *xG = NULL;
53	0	BIGNUM *yG = NULL;
54	0	BIGNUM *xA = NULL;
55	0	BIGNUM *yA = NULL;
56	0	int p_bytes = 0;
57	0	uint8_t *buf = NULL;
58	0	uint16_t entl = 0;
59	0	uint8_t e_byte = 0;
60
61		/* SM2 Signatures require a public key, check for it */
62	0	if (pubkey == NULL) {
63	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
64	0	goto done;
65	0	}
66
67	0	hash = EVP_MD_CTX_new();
68	0	if (hash == NULL) {
69	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
70	0	goto done;
71	0	}
72	0	ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
73	0	if (ctx == NULL) {
74	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
75	0	goto done;
76	0	}
77
78	0	BN_CTX_start(ctx);
79	0	p = BN_CTX_get(ctx);
80	0	a = BN_CTX_get(ctx);
81	0	b = BN_CTX_get(ctx);
82	0	xG = BN_CTX_get(ctx);
83	0	yG = BN_CTX_get(ctx);
84	0	xA = BN_CTX_get(ctx);
85	0	yA = BN_CTX_get(ctx);
86
87	0	if (yA == NULL) {
88	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
89	0	goto done;
90	0	}
91
92	0	if (!EVP_DigestInit(hash, digest)) {
93	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
94	0	goto done;
95	0	}
96
97		/* Z = h(ENTL \|\| ID \|\| a \|\| b \|\| xG \|\| yG \|\| xA \|\| yA) */
98
99	0	if (id == NULL) {
100	0	id = default_sm2_id;
101	0	id_len = sizeof(default_sm2_id);
102	0	}
103
104	0	if (id_len >= (UINT16_MAX / 8)) {
105		/* too large */
106	0	ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
107	0	goto done;
108	0	}
109
110	0	entl = (uint16_t)(8 * id_len);
111
112	0	e_byte = entl >> 8;
113	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
114	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
115	0	goto done;
116	0	}
117	0	e_byte = entl & 0xFF;
118	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
119	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
120	0	goto done;
121	0	}
122
123	0	if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
124	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
125	0	goto done;
126	0	}
127
128	0	if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
129	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
130	0	goto done;
131	0	}
132
133	0	p_bytes = BN_num_bytes(p);
134	0	buf = OPENSSL_zalloc(p_bytes);
135	0	if (buf == NULL)
136	0	goto done;
137
138	0	if (BN_bn2binpad(a, buf, p_bytes) < 0
139	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
140	0	\|\| BN_bn2binpad(b, buf, p_bytes) < 0
141	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
142	0	\|\| !EC_POINT_get_affine_coordinates(group,
143	0	EC_GROUP_get0_generator(group),
144	0	xG, yG, ctx)
145	0	\|\| BN_bn2binpad(xG, buf, p_bytes) < 0
146	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
147	0	\|\| BN_bn2binpad(yG, buf, p_bytes) < 0
148	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
149	0	\|\| !EC_POINT_get_affine_coordinates(group,
150	0	pubkey,
151	0	xA, yA, ctx)
152	0	\|\| BN_bn2binpad(xA, buf, p_bytes) < 0
153	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
154	0	\|\| BN_bn2binpad(yA, buf, p_bytes) < 0
155	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
156	0	\|\| !EVP_DigestFinal(hash, out, NULL)) {
157	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
158	0	goto done;
159	0	}
160
161	0	rc = 1;
162
163	0	done:
164	0	OPENSSL_free(buf);
165	0	BN_CTX_end(ctx);
166	0	BN_CTX_free(ctx);
167	0	EVP_MD_CTX_free(hash);
168	0	return rc;
169	0	}
170
171		static BIGNUM sm2_compute_msg_hash(const EVP_MD digest,
172		const EC_KEY *key,
173		const uint8_t *id,
174		const size_t id_len,
175		const uint8_t *msg, size_t msg_len)
176	0	{
177	0	EVP_MD_CTX *hash = EVP_MD_CTX_new();
178	0	const int md_size = EVP_MD_get_size(digest);
179	0	uint8_t *z = NULL;
180	0	BIGNUM *e = NULL;
181	0	EVP_MD *fetched_digest = NULL;
182	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
183	0	const char *propq = ossl_ec_key_get0_propq(key);
184
185	0	if (md_size <= 0) {
186	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
187	0	goto done;
188	0	}
189	0	if (hash == NULL) {
190	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
191	0	goto done;
192	0	}
193
194	0	z = OPENSSL_zalloc(md_size);
195	0	if (z == NULL)
196	0	goto done;
197
198	0	fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
199	0	if (fetched_digest == NULL) {
200	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
201	0	goto done;
202	0	}
203
204	0	if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
205		/* SM2err already called */
206	0	goto done;
207	0	}
208
209	0	if (!EVP_DigestInit(hash, fetched_digest)
210	0	\|\| !EVP_DigestUpdate(hash, z, md_size)
211	0	\|\| !EVP_DigestUpdate(hash, msg, msg_len)
212		/* reuse z buffer to hold H(Z \|\| M) */
213	0	\|\| !EVP_DigestFinal(hash, z, NULL)) {
214	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
215	0	goto done;
216	0	}
217
218	0	e = BN_bin2bn(z, md_size, NULL);
219	0	if (e == NULL)
220	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
221
222	0	done:
223	0	EVP_MD_free(fetched_digest);
224	0	OPENSSL_free(z);
225	0	EVP_MD_CTX_free(hash);
226	0	return e;
227	0	}
228
229		static ECDSA_SIG sm2_sig_gen(const EC_KEY key, const BIGNUM *e)
230	0	{
231	0	const BIGNUM *dA = EC_KEY_get0_private_key(key);
232	0	const EC_GROUP *group = EC_KEY_get0_group(key);
233	0	const BIGNUM *order = EC_GROUP_get0_order(group);
234	0	ECDSA_SIG *sig = NULL;
235	0	EC_POINT *kG = NULL;
236	0	BN_CTX *ctx = NULL;
237	0	BIGNUM *k = NULL;
238	0	BIGNUM *rk = NULL;
239	0	BIGNUM *r = NULL;
240	0	BIGNUM *s = NULL;
241	0	BIGNUM *x1 = NULL;
242	0	BIGNUM *tmp = NULL;
243	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
244
245	0	if (dA == NULL) {
246	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_PRIVATE_KEY);
247	0	goto done;
248	0	}
249	0	kG = EC_POINT_new(group);
250	0	if (kG == NULL) {
251	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
252	0	goto done;
253	0	}
254	0	ctx = BN_CTX_new_ex(libctx);
255	0	if (ctx == NULL) {
256	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
257	0	goto done;
258	0	}
259
260	0	BN_CTX_start(ctx);
261	0	k = BN_CTX_get(ctx);
262	0	rk = BN_CTX_get(ctx);
263	0	x1 = BN_CTX_get(ctx);
264	0	tmp = BN_CTX_get(ctx);
265	0	if (tmp == NULL) {
266	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
267	0	goto done;
268	0	}
269
270		/*
271		* These values are returned and so should not be allocated out of the
272		* context
273		*/
274	0	r = BN_new();
275	0	s = BN_new();
276
277	0	if (r == NULL \|\| s == NULL) {
278	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
279	0	goto done;
280	0	}
281
282		/*
283		* A3: Generate a random number k in [1,n-1] using random number generators;
284		* A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
285		* as specified in clause 4.2.8 of GM/T 0003.1-2012;
286		* A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
287		* A6: Compute s=(1/(1+dA)(k-rdA)) mod n. If s=0, then go to A3;
288		* A7: Convert the type of data (r,s) to be bit strings according to the details
289		* in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
290		*/
291	0	for (;;) {
292	0	if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
293	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
294	0	goto done;
295	0	}
296
297	0	if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
298	0	\|\| !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
299	0	ctx)
300	0	\|\| !BN_mod_add(r, e, x1, order, ctx)) {
301	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
302	0	goto done;
303	0	}
304
305		/* try again if r == 0 or r+k == n */
306	0	if (BN_is_zero(r))
307	0	continue;
308
309	0	if (!BN_add(rk, r, k)) {
310	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
311	0	goto done;
312	0	}
313
314	0	if (BN_cmp(rk, order) == 0)
315	0	continue;
316
317	0	if (!BN_add(s, dA, BN_value_one())
318	0	\|\| !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
319	0	\|\| !BN_mod_mul(tmp, dA, r, order, ctx)
320	0	\|\| !BN_sub(tmp, k, tmp)
321	0	\|\| !BN_mod_mul(s, s, tmp, order, ctx)) {
322	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
323	0	goto done;
324	0	}
325
326		/* try again if s == 0 */
327	0	if (BN_is_zero(s))
328	0	continue;
329
330	0	sig = ECDSA_SIG_new();
331	0	if (sig == NULL) {
332	0	ERR_raise(ERR_LIB_SM2, ERR_R_ECDSA_LIB);
333	0	goto done;
334	0	}
335
336		/* takes ownership of r and s */
337	0	ECDSA_SIG_set0(sig, r, s);
338	0	break;
339	0	}
340
341	0	done:
342	0	if (sig == NULL) {
343	0	BN_free(r);
344	0	BN_free(s);
345	0	}
346
347	0	BN_CTX_end(ctx);
348	0	BN_CTX_free(ctx);
349	0	EC_POINT_free(kG);
350	0	return sig;
351	0	}
352
353		static int sm2_sig_verify(const EC_KEY key, const ECDSA_SIG sig,
354		const BIGNUM *e)
355	0	{
356	0	int ret = 0;
357	0	const EC_GROUP *group = EC_KEY_get0_group(key);
358	0	const BIGNUM *order = EC_GROUP_get0_order(group);
359	0	BN_CTX *ctx = NULL;
360	0	EC_POINT *pt = NULL;
361	0	BIGNUM *t = NULL;
362	0	BIGNUM *x1 = NULL;
363	0	const BIGNUM *r = NULL;
364	0	const BIGNUM *s = NULL;
365	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
366
367	0	ctx = BN_CTX_new_ex(libctx);
368	0	if (ctx == NULL) {
369	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
370	0	goto done;
371	0	}
372	0	BN_CTX_start(ctx);
373	0	t = BN_CTX_get(ctx);
374	0	x1 = BN_CTX_get(ctx);
375	0	if (x1 == NULL) {
376	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
377	0	goto done;
378	0	}
379
380	0	pt = EC_POINT_new(group);
381	0	if (pt == NULL) {
382	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
383	0	goto done;
384	0	}
385
386		/*
387		* B1: verify whether r' in [1,n-1], verification failed if not
388		* B2: verify whether s' in [1,n-1], verification failed if not
389		* B3: set M'~=ZA \|\| M'
390		* B4: calculate e'=Hv(M'~)
391		* B5: calculate t = (r' + s') modn, verification failed if t=0
392		* B6: calculate the point (x1', y1')=[s']G + [t]PA
393		* B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
394		*/
395
396	0	ECDSA_SIG_get0(sig, &r, &s);
397
398	0	if (BN_cmp(r, BN_value_one()) < 0
399	0	\|\| BN_cmp(s, BN_value_one()) < 0
400	0	\|\| BN_cmp(order, r) <= 0
401	0	\|\| BN_cmp(order, s) <= 0) {
402	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
403	0	goto done;
404	0	}
405
406	0	if (!BN_mod_add(t, r, s, order, ctx)) {
407	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
408	0	goto done;
409	0	}
410
411	0	if (BN_is_zero(t)) {
412	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
413	0	goto done;
414	0	}
415
416	0	if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
417	0	\|\| !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
418	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
419	0	goto done;
420	0	}
421
422	0	if (!BN_mod_add(t, e, x1, order, ctx)) {
423	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
424	0	goto done;
425	0	}
426
427	0	if (BN_cmp(r, t) == 0)
428	0	ret = 1;
429
430	0	done:
431	0	EC_POINT_free(pt);
432	0	BN_CTX_end(ctx);
433	0	BN_CTX_free(ctx);
434	0	return ret;
435	0	}
436
437		ECDSA_SIG ossl_sm2_do_sign(const EC_KEY key,
438		const EVP_MD *digest,
439		const uint8_t *id,
440		const size_t id_len,
441		const uint8_t *msg, size_t msg_len)
442	0	{
443	0	BIGNUM *e = NULL;
444	0	ECDSA_SIG *sig = NULL;
445
446	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
447	0	if (e == NULL) {
448		/* SM2err already called */
449	0	goto done;
450	0	}
451
452	0	sig = sm2_sig_gen(key, e);
453
454	0	done:
455	0	BN_free(e);
456	0	return sig;
457	0	}
458
459		int ossl_sm2_do_verify(const EC_KEY *key,
460		const EVP_MD *digest,
461		const ECDSA_SIG *sig,
462		const uint8_t *id,
463		const size_t id_len,
464		const uint8_t *msg, size_t msg_len)
465	0	{
466	0	BIGNUM *e = NULL;
467	0	int ret = 0;
468
469	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
470	0	if (e == NULL) {
471		/* SM2err already called */
472	0	goto done;
473	0	}
474
475	0	ret = sm2_sig_verify(key, sig, e);
476
477	0	done:
478	0	BN_free(e);
479	0	return ret;
480	0	}
481
482		int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
483		unsigned char sig, unsigned int siglen,
484		EC_KEY *eckey)
485	0	{
486	0	BIGNUM *e = NULL;
487	0	ECDSA_SIG *s = NULL;
488	0	int sigleni;
489	0	int ret = -1;
490
491	0	if (sig == NULL) {
492	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
493	0	goto done;
494	0	}
495
496	0	e = BN_bin2bn(dgst, dgstlen, NULL);
497	0	if (e == NULL) {
498	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
499	0	goto done;
500	0	}
501
502	0	s = sm2_sig_gen(eckey, e);
503	0	if (s == NULL) {
504	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
505	0	goto done;
506	0	}
507
508	0	sigleni = i2d_ECDSA_SIG(s, &sig);
509	0	if (sigleni < 0) {
510	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
511	0	goto done;
512	0	}
513	0	*siglen = (unsigned int)sigleni;
514
515	0	ret = 1;
516
517	0	done:
518	0	ECDSA_SIG_free(s);
519	0	BN_free(e);
520	0	return ret;
521	0	}
522
523		int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
524		const unsigned char *sig, int sig_len,
525		EC_KEY *eckey)
526	0	{
527	0	ECDSA_SIG *s = NULL;
528	0	BIGNUM *e = NULL;
529	0	const unsigned char *p = sig;
530	0	unsigned char *der = NULL;
531	0	int derlen = -1;
532	0	int ret = -1;
533
534	0	s = ECDSA_SIG_new();
535	0	if (s == NULL) {
536	0	ERR_raise(ERR_LIB_SM2, ERR_R_ECDSA_LIB);
537	0	goto done;
538	0	}
539	0	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
540	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
541	0	goto done;
542	0	}
543		/* Ensure signature uses DER and doesn't have trailing garbage */
544	0	derlen = i2d_ECDSA_SIG(s, &der);
545	0	if (derlen != sig_len \|\| memcmp(sig, der, derlen) != 0) {
546	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
547	0	goto done;
548	0	}
549
550	0	e = BN_bin2bn(dgst, dgstlen, NULL);
551	0	if (e == NULL) {
552	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
553	0	goto done;
554	0	}
555
556	0	ret = sm2_sig_verify(eckey, s, e);
557
558	0	done:
559	0	OPENSSL_free(der);
560	0	BN_free(e);
561	0	ECDSA_SIG_free(s);
562	0	return ret;
563	0	}