/src/openssl/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>

/*
 * [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;
    }

    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_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_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:
    BN_CTX_end(ctx);
    EC_POINT_free(pt);
    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: 2026-02-22 06:11

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