/src/openssl35/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/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();
    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_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: 2026-05-24 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/bn.h>
21		#include <string.h>
22
23		int ossl_sm2_compute_z_digest(uint8_t *out,
24		const EVP_MD *digest,
25		const uint8_t *id,
26		const size_t id_len,
27		const EC_KEY *key)
28	0	{
29	0	int rc = 0;
30	0	const EC_GROUP *group = EC_KEY_get0_group(key);
31	0	const EC_POINT *pubkey = EC_KEY_get0_public_key(key);
32	0	BN_CTX *ctx = NULL;
33	0	EVP_MD_CTX *hash = NULL;
34	0	BIGNUM *p = NULL;
35	0	BIGNUM *a = NULL;
36	0	BIGNUM *b = NULL;
37	0	BIGNUM *xG = NULL;
38	0	BIGNUM *yG = NULL;
39	0	BIGNUM *xA = NULL;
40	0	BIGNUM *yA = NULL;
41	0	int p_bytes = 0;
42	0	uint8_t *buf = NULL;
43	0	uint16_t entl = 0;
44	0	uint8_t e_byte = 0;
45
46		/* SM2 Signatures require a public key, check for it */
47	0	if (pubkey == NULL) {
48	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
49	0	goto done;
50	0	}
51
52	0	hash = EVP_MD_CTX_new();
53	0	if (hash == NULL) {
54	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
55	0	goto done;
56	0	}
57	0	ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
58	0	if (ctx == NULL) {
59	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
60	0	goto done;
61	0	}
62
63	0	BN_CTX_start(ctx);
64	0	p = BN_CTX_get(ctx);
65	0	a = BN_CTX_get(ctx);
66	0	b = BN_CTX_get(ctx);
67	0	xG = BN_CTX_get(ctx);
68	0	yG = BN_CTX_get(ctx);
69	0	xA = BN_CTX_get(ctx);
70	0	yA = BN_CTX_get(ctx);
71
72	0	if (yA == NULL) {
73	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
74	0	goto done;
75	0	}
76
77	0	if (!EVP_DigestInit(hash, digest)) {
78	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
79	0	goto done;
80	0	}
81
82		/* Z = h(ENTL \|\| ID \|\| a \|\| b \|\| xG \|\| yG \|\| xA \|\| yA) */
83
84	0	if (id_len >= (UINT16_MAX / 8)) {
85		/* too large */
86	0	ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
87	0	goto done;
88	0	}
89
90	0	entl = (uint16_t)(8 * id_len);
91
92	0	e_byte = entl >> 8;
93	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
94	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
95	0	goto done;
96	0	}
97	0	e_byte = entl & 0xFF;
98	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
99	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
100	0	goto done;
101	0	}
102
103	0	if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
104	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
105	0	goto done;
106	0	}
107
108	0	if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
109	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
110	0	goto done;
111	0	}
112
113	0	p_bytes = BN_num_bytes(p);
114	0	buf = OPENSSL_zalloc(p_bytes);
115	0	if (buf == NULL)
116	0	goto done;
117
118	0	if (BN_bn2binpad(a, buf, p_bytes) < 0
119	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
120	0	\|\| BN_bn2binpad(b, buf, p_bytes) < 0
121	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
122	0	\|\| !EC_POINT_get_affine_coordinates(group,
123	0	EC_GROUP_get0_generator(group),
124	0	xG, yG, ctx)
125	0	\|\| BN_bn2binpad(xG, buf, p_bytes) < 0
126	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
127	0	\|\| BN_bn2binpad(yG, buf, p_bytes) < 0
128	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
129	0	\|\| !EC_POINT_get_affine_coordinates(group,
130	0	pubkey,
131	0	xA, yA, ctx)
132	0	\|\| BN_bn2binpad(xA, buf, p_bytes) < 0
133	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
134	0	\|\| BN_bn2binpad(yA, buf, p_bytes) < 0
135	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
136	0	\|\| !EVP_DigestFinal(hash, out, NULL)) {
137	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
138	0	goto done;
139	0	}
140
141	0	rc = 1;
142
143	0	done:
144	0	OPENSSL_free(buf);
145	0	BN_CTX_end(ctx);
146	0	BN_CTX_free(ctx);
147	0	EVP_MD_CTX_free(hash);
148	0	return rc;
149	0	}
150
151		static BIGNUM sm2_compute_msg_hash(const EVP_MD digest,
152		const EC_KEY *key,
153		const uint8_t *id,
154		const size_t id_len,
155		const uint8_t *msg, size_t msg_len)
156	0	{
157	0	EVP_MD_CTX *hash = EVP_MD_CTX_new();
158	0	const int md_size = EVP_MD_get_size(digest);
159	0	uint8_t *z = NULL;
160	0	BIGNUM *e = NULL;
161	0	EVP_MD *fetched_digest = NULL;
162	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
163	0	const char *propq = ossl_ec_key_get0_propq(key);
164
165	0	if (md_size <= 0) {
166	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
167	0	goto done;
168	0	}
169	0	if (hash == NULL) {
170	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
171	0	goto done;
172	0	}
173
174	0	z = OPENSSL_zalloc(md_size);
175	0	if (z == NULL)
176	0	goto done;
177
178	0	fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
179	0	if (fetched_digest == NULL) {
180	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
181	0	goto done;
182	0	}
183
184	0	if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
185		/* SM2err already called */
186	0	goto done;
187	0	}
188
189	0	if (!EVP_DigestInit(hash, fetched_digest)
190	0	\|\| !EVP_DigestUpdate(hash, z, md_size)
191	0	\|\| !EVP_DigestUpdate(hash, msg, msg_len)
192		/* reuse z buffer to hold H(Z \|\| M) */
193	0	\|\| !EVP_DigestFinal(hash, z, NULL)) {
194	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
195	0	goto done;
196	0	}
197
198	0	e = BN_bin2bn(z, md_size, NULL);
199	0	if (e == NULL)
200	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
201
202	0	done:
203	0	EVP_MD_free(fetched_digest);
204	0	OPENSSL_free(z);
205	0	EVP_MD_CTX_free(hash);
206	0	return e;
207	0	}
208
209		static ECDSA_SIG sm2_sig_gen(const EC_KEY key, const BIGNUM *e)
210	0	{
211	0	const BIGNUM *dA = EC_KEY_get0_private_key(key);
212	0	const EC_GROUP *group = EC_KEY_get0_group(key);
213	0	const BIGNUM *order = EC_GROUP_get0_order(group);
214	0	ECDSA_SIG *sig = NULL;
215	0	EC_POINT *kG = NULL;
216	0	BN_CTX *ctx = NULL;
217	0	BIGNUM *k = NULL;
218	0	BIGNUM *rk = NULL;
219	0	BIGNUM *r = NULL;
220	0	BIGNUM *s = NULL;
221	0	BIGNUM *x1 = NULL;
222	0	BIGNUM *tmp = NULL;
223	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
224
225	0	if (dA == NULL) {
226	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_PRIVATE_KEY);
227	0	goto done;
228	0	}
229	0	kG = EC_POINT_new(group);
230	0	if (kG == NULL) {
231	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
232	0	goto done;
233	0	}
234	0	ctx = BN_CTX_new_ex(libctx);
235	0	if (ctx == NULL) {
236	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
237	0	goto done;
238	0	}
239
240	0	BN_CTX_start(ctx);
241	0	k = BN_CTX_get(ctx);
242	0	rk = BN_CTX_get(ctx);
243	0	x1 = BN_CTX_get(ctx);
244	0	tmp = BN_CTX_get(ctx);
245	0	if (tmp == NULL) {
246	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
247	0	goto done;
248	0	}
249
250		/*
251		* These values are returned and so should not be allocated out of the
252		* context
253		*/
254	0	r = BN_new();
255	0	s = BN_new();
256
257	0	if (r == NULL \|\| s == NULL) {
258	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
259	0	goto done;
260	0	}
261
262		/*
263		* A3: Generate a random number k in [1,n-1] using random number generators;
264		* A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
265		* as specified in clause 4.2.8 of GM/T 0003.1-2012;
266		* A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
267		* A6: Compute s=(1/(1+dA)(k-rdA)) mod n. If s=0, then go to A3;
268		* A7: Convert the type of data (r,s) to be bit strings according to the details
269		* in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
270		*/
271	0	for (;;) {
272	0	if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
273	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
274	0	goto done;
275	0	}
276
277	0	if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
278	0	\|\| !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
279	0	ctx)
280	0	\|\| !BN_mod_add(r, e, x1, order, ctx)) {
281	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
282	0	goto done;
283	0	}
284
285		/* try again if r == 0 or r+k == n */
286	0	if (BN_is_zero(r))
287	0	continue;
288
289	0	if (!BN_add(rk, r, k)) {
290	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
291	0	goto done;
292	0	}
293
294	0	if (BN_cmp(rk, order) == 0)
295	0	continue;
296
297	0	if (!BN_add(s, dA, BN_value_one())
298	0	\|\| !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
299	0	\|\| !BN_mod_mul(tmp, dA, r, order, ctx)
300	0	\|\| !BN_sub(tmp, k, tmp)
301	0	\|\| !BN_mod_mul(s, s, tmp, order, ctx)) {
302	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
303	0	goto done;
304	0	}
305
306		/* try again if s == 0 */
307	0	if (BN_is_zero(s))
308	0	continue;
309
310	0	sig = ECDSA_SIG_new();
311	0	if (sig == NULL) {
312	0	ERR_raise(ERR_LIB_SM2, ERR_R_ECDSA_LIB);
313	0	goto done;
314	0	}
315
316		/* takes ownership of r and s */
317	0	ECDSA_SIG_set0(sig, r, s);
318	0	break;
319	0	}
320
321	0	done:
322	0	if (sig == NULL) {
323	0	BN_free(r);
324	0	BN_free(s);
325	0	}
326
327	0	BN_CTX_end(ctx);
328	0	BN_CTX_free(ctx);
329	0	EC_POINT_free(kG);
330	0	return sig;
331	0	}
332
333		static int sm2_sig_verify(const EC_KEY key, const ECDSA_SIG sig,
334		const BIGNUM *e)
335	0	{
336	0	int ret = 0;
337	0	const EC_GROUP *group = EC_KEY_get0_group(key);
338	0	const BIGNUM *order = EC_GROUP_get0_order(group);
339	0	BN_CTX *ctx = NULL;
340	0	EC_POINT *pt = NULL;
341	0	BIGNUM *t = NULL;
342	0	BIGNUM *x1 = NULL;
343	0	const BIGNUM *r = NULL;
344	0	const BIGNUM *s = NULL;
345	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
346
347	0	ctx = BN_CTX_new_ex(libctx);
348	0	if (ctx == NULL) {
349	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
350	0	goto done;
351	0	}
352	0	BN_CTX_start(ctx);
353	0	t = BN_CTX_get(ctx);
354	0	x1 = BN_CTX_get(ctx);
355	0	if (x1 == NULL) {
356	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
357	0	goto done;
358	0	}
359
360	0	pt = EC_POINT_new(group);
361	0	if (pt == NULL) {
362	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
363	0	goto done;
364	0	}
365
366		/*
367		* B1: verify whether r' in [1,n-1], verification failed if not
368		* B2: verify whether s' in [1,n-1], verification failed if not
369		* B3: set M'~=ZA \|\| M'
370		* B4: calculate e'=Hv(M'~)
371		* B5: calculate t = (r' + s') modn, verification failed if t=0
372		* B6: calculate the point (x1', y1')=[s']G + [t]PA
373		* B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
374		*/
375
376	0	ECDSA_SIG_get0(sig, &r, &s);
377
378	0	if (BN_cmp(r, BN_value_one()) < 0
379	0	\|\| BN_cmp(s, BN_value_one()) < 0
380	0	\|\| BN_cmp(order, r) <= 0
381	0	\|\| BN_cmp(order, s) <= 0) {
382	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
383	0	goto done;
384	0	}
385
386	0	if (!BN_mod_add(t, r, s, order, ctx)) {
387	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
388	0	goto done;
389	0	}
390
391	0	if (BN_is_zero(t)) {
392	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
393	0	goto done;
394	0	}
395
396	0	if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
397	0	\|\| !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
398	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
399	0	goto done;
400	0	}
401
402	0	if (!BN_mod_add(t, e, x1, order, ctx)) {
403	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
404	0	goto done;
405	0	}
406
407	0	if (BN_cmp(r, t) == 0)
408	0	ret = 1;
409
410	0	done:
411	0	EC_POINT_free(pt);
412	0	BN_CTX_end(ctx);
413	0	BN_CTX_free(ctx);
414	0	return ret;
415	0	}
416
417		ECDSA_SIG ossl_sm2_do_sign(const EC_KEY key,
418		const EVP_MD *digest,
419		const uint8_t *id,
420		const size_t id_len,
421		const uint8_t *msg, size_t msg_len)
422	0	{
423	0	BIGNUM *e = NULL;
424	0	ECDSA_SIG *sig = NULL;
425
426	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
427	0	if (e == NULL) {
428		/* SM2err already called */
429	0	goto done;
430	0	}
431
432	0	sig = sm2_sig_gen(key, e);
433
434	0	done:
435	0	BN_free(e);
436	0	return sig;
437	0	}
438
439		int ossl_sm2_do_verify(const EC_KEY *key,
440		const EVP_MD *digest,
441		const ECDSA_SIG *sig,
442		const uint8_t *id,
443		const size_t id_len,
444		const uint8_t *msg, size_t msg_len)
445	0	{
446	0	BIGNUM *e = NULL;
447	0	int ret = 0;
448
449	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
450	0	if (e == NULL) {
451		/* SM2err already called */
452	0	goto done;
453	0	}
454
455	0	ret = sm2_sig_verify(key, sig, e);
456
457	0	done:
458	0	BN_free(e);
459	0	return ret;
460	0	}
461
462		int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
463		unsigned char sig, unsigned int siglen,
464		EC_KEY *eckey)
465	0	{
466	0	BIGNUM *e = NULL;
467	0	ECDSA_SIG *s = NULL;
468	0	int sigleni;
469	0	int ret = -1;
470
471	0	if (sig == NULL) {
472	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
473	0	goto done;
474	0	}
475
476	0	e = BN_bin2bn(dgst, dgstlen, NULL);
477	0	if (e == NULL) {
478	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
479	0	goto done;
480	0	}
481
482	0	s = sm2_sig_gen(eckey, e);
483	0	if (s == NULL) {
484	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
485	0	goto done;
486	0	}
487
488	0	sigleni = i2d_ECDSA_SIG(s, &sig);
489	0	if (sigleni < 0) {
490	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
491	0	goto done;
492	0	}
493	0	*siglen = (unsigned int)sigleni;
494
495	0	ret = 1;
496
497	0	done:
498	0	ECDSA_SIG_free(s);
499	0	BN_free(e);
500	0	return ret;
501	0	}
502
503		int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
504		const unsigned char *sig, int sig_len,
505		EC_KEY *eckey)
506	0	{
507	0	ECDSA_SIG *s = NULL;
508	0	BIGNUM *e = NULL;
509	0	const unsigned char *p = sig;
510	0	unsigned char *der = NULL;
511	0	int derlen = -1;
512	0	int ret = -1;
513
514	0	s = ECDSA_SIG_new();
515	0	if (s == NULL) {
516	0	ERR_raise(ERR_LIB_SM2, ERR_R_ECDSA_LIB);
517	0	goto done;
518	0	}
519	0	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
520	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
521	0	goto done;
522	0	}
523		/* Ensure signature uses DER and doesn't have trailing garbage */
524	0	derlen = i2d_ECDSA_SIG(s, &der);
525	0	if (derlen != sig_len \|\| memcmp(sig, der, derlen) != 0) {
526	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
527	0	goto done;
528	0	}
529
530	0	e = BN_bin2bn(dgst, dgstlen, NULL);
531	0	if (e == NULL) {
532	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
533	0	goto done;
534	0	}
535
536	0	ret = sm2_sig_verify(eckey, s, e);
537
538	0	done:
539	0	OPENSSL_free(der);
540	0	BN_free(e);
541	0	ECDSA_SIG_free(s);
542	0	return ret;
543	0	}