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

Source (jump to first uncovered line)
/*
 * Copyright 2017-2023 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);
    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;

    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;
    }

    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,
                                                EC_KEY_get0_public_key(key),
                                                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;
    }

    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);

    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_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);
    pt = EC_POINT_new(group);
    if (ctx == NULL || pt == 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;
    }

    /*
     * 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_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;

    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 != NULL ? &sig : NULL);
    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: 2023-06-08 06:41

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2017-2023 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	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	0	hash = EVP_MD_CTX_new();
47	0	ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
48	0	if (hash == NULL \|\| ctx == NULL) {
49	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
50	0	goto done;
51	0	}
52
53	0	p = BN_CTX_get(ctx);
54	0	a = BN_CTX_get(ctx);
55	0	b = BN_CTX_get(ctx);
56	0	xG = BN_CTX_get(ctx);
57	0	yG = BN_CTX_get(ctx);
58	0	xA = BN_CTX_get(ctx);
59	0	yA = BN_CTX_get(ctx);
60
61	0	if (yA == NULL) {
62	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
63	0	goto done;
64	0	}
65
66	0	if (!EVP_DigestInit(hash, digest)) {
67	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
68	0	goto done;
69	0	}
70
71		/* Z = h(ENTL \|\| ID \|\| a \|\| b \|\| xG \|\| yG \|\| xA \|\| yA) */
72
73	0	if (id_len >= (UINT16_MAX / 8)) {
74		/* too large */
75	0	ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
76	0	goto done;
77	0	}
78
79	0	entl = (uint16_t)(8 * id_len);
80
81	0	e_byte = entl >> 8;
82	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
83	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
84	0	goto done;
85	0	}
86	0	e_byte = entl & 0xFF;
87	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
88	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
89	0	goto done;
90	0	}
91
92	0	if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
93	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
94	0	goto done;
95	0	}
96
97	0	if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
98	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
99	0	goto done;
100	0	}
101
102	0	p_bytes = BN_num_bytes(p);
103	0	buf = OPENSSL_zalloc(p_bytes);
104	0	if (buf == NULL) {
105	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
106	0	goto done;
107	0	}
108
109	0	if (BN_bn2binpad(a, buf, p_bytes) < 0
110	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
111	0	\|\| BN_bn2binpad(b, buf, p_bytes) < 0
112	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
113	0	\|\| !EC_POINT_get_affine_coordinates(group,
114	0	EC_GROUP_get0_generator(group),
115	0	xG, yG, ctx)
116	0	\|\| BN_bn2binpad(xG, buf, p_bytes) < 0
117	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
118	0	\|\| BN_bn2binpad(yG, buf, p_bytes) < 0
119	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
120	0	\|\| !EC_POINT_get_affine_coordinates(group,
121	0	EC_KEY_get0_public_key(key),
122	0	xA, yA, ctx)
123	0	\|\| BN_bn2binpad(xA, buf, p_bytes) < 0
124	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
125	0	\|\| BN_bn2binpad(yA, buf, p_bytes) < 0
126	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
127	0	\|\| !EVP_DigestFinal(hash, out, NULL)) {
128	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
129	0	goto done;
130	0	}
131
132	0	rc = 1;
133
134	0	done:
135	0	OPENSSL_free(buf);
136	0	BN_CTX_free(ctx);
137	0	EVP_MD_CTX_free(hash);
138	0	return rc;
139	0	}
140
141		static BIGNUM sm2_compute_msg_hash(const EVP_MD digest,
142		const EC_KEY *key,
143		const uint8_t *id,
144		const size_t id_len,
145		const uint8_t *msg, size_t msg_len)
146	0	{
147	0	EVP_MD_CTX *hash = EVP_MD_CTX_new();
148	0	const int md_size = EVP_MD_get_size(digest);
149	0	uint8_t *z = NULL;
150	0	BIGNUM *e = NULL;
151	0	EVP_MD *fetched_digest = NULL;
152	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
153	0	const char *propq = ossl_ec_key_get0_propq(key);
154
155	0	if (md_size < 0) {
156	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
157	0	goto done;
158	0	}
159
160	0	z = OPENSSL_zalloc(md_size);
161	0	if (hash == NULL \|\| z == NULL) {
162	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
163	0	goto done;
164	0	}
165
166	0	fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
167	0	if (fetched_digest == NULL) {
168	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
169	0	goto done;
170	0	}
171
172	0	if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
173		/* SM2err already called */
174	0	goto done;
175	0	}
176
177	0	if (!EVP_DigestInit(hash, fetched_digest)
178	0	\|\| !EVP_DigestUpdate(hash, z, md_size)
179	0	\|\| !EVP_DigestUpdate(hash, msg, msg_len)
180		/* reuse z buffer to hold H(Z \|\| M) */
181	0	\|\| !EVP_DigestFinal(hash, z, NULL)) {
182	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
183	0	goto done;
184	0	}
185
186	0	e = BN_bin2bn(z, md_size, NULL);
187	0	if (e == NULL)
188	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
189
190	0	done:
191	0	EVP_MD_free(fetched_digest);
192	0	OPENSSL_free(z);
193	0	EVP_MD_CTX_free(hash);
194	0	return e;
195	0	}
196
197		static ECDSA_SIG sm2_sig_gen(const EC_KEY key, const BIGNUM *e)
198	0	{
199	0	const BIGNUM *dA = EC_KEY_get0_private_key(key);
200	0	const EC_GROUP *group = EC_KEY_get0_group(key);
201	0	const BIGNUM *order = EC_GROUP_get0_order(group);
202	0	ECDSA_SIG *sig = NULL;
203	0	EC_POINT *kG = NULL;
204	0	BN_CTX *ctx = NULL;
205	0	BIGNUM *k = NULL;
206	0	BIGNUM *rk = NULL;
207	0	BIGNUM *r = NULL;
208	0	BIGNUM *s = NULL;
209	0	BIGNUM *x1 = NULL;
210	0	BIGNUM *tmp = NULL;
211	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
212
213	0	kG = EC_POINT_new(group);
214	0	ctx = BN_CTX_new_ex(libctx);
215	0	if (kG == NULL \|\| ctx == NULL) {
216	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
217	0	goto done;
218	0	}
219
220	0	BN_CTX_start(ctx);
221	0	k = BN_CTX_get(ctx);
222	0	rk = BN_CTX_get(ctx);
223	0	x1 = BN_CTX_get(ctx);
224	0	tmp = BN_CTX_get(ctx);
225	0	if (tmp == NULL) {
226	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
227	0	goto done;
228	0	}
229
230		/*
231		* These values are returned and so should not be allocated out of the
232		* context
233		*/
234	0	r = BN_new();
235	0	s = BN_new();
236
237	0	if (r == NULL \|\| s == NULL) {
238	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
239	0	goto done;
240	0	}
241
242		/*
243		* A3: Generate a random number k in [1,n-1] using random number generators;
244		* A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
245		* as specified in clause 4.2.8 of GM/T 0003.1-2012;
246		* A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
247		* A6: Compute s=(1/(1+dA)(k-rdA)) mod n. If s=0, then go to A3;
248		* A7: Convert the type of data (r,s) to be bit strings according to the details
249		* in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
250		*/
251	0	for (;;) {
252	0	if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
253	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
254	0	goto done;
255	0	}
256
257	0	if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
258	0	\|\| !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
259	0	ctx)
260	0	\|\| !BN_mod_add(r, e, x1, order, ctx)) {
261	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
262	0	goto done;
263	0	}
264
265		/* try again if r == 0 or r+k == n */
266	0	if (BN_is_zero(r))
267	0	continue;
268
269	0	if (!BN_add(rk, r, k)) {
270	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
271	0	goto done;
272	0	}
273
274	0	if (BN_cmp(rk, order) == 0)
275	0	continue;
276
277	0	if (!BN_add(s, dA, BN_value_one())
278	0	\|\| !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
279	0	\|\| !BN_mod_mul(tmp, dA, r, order, ctx)
280	0	\|\| !BN_sub(tmp, k, tmp)
281	0	\|\| !BN_mod_mul(s, s, tmp, order, ctx)) {
282	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
283	0	goto done;
284	0	}
285
286		/* try again if s == 0 */
287	0	if (BN_is_zero(s))
288	0	continue;
289
290	0	sig = ECDSA_SIG_new();
291	0	if (sig == NULL) {
292	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
293	0	goto done;
294	0	}
295
296		/* takes ownership of r and s */
297	0	ECDSA_SIG_set0(sig, r, s);
298	0	break;
299	0	}
300
301	0	done:
302	0	if (sig == NULL) {
303	0	BN_free(r);
304	0	BN_free(s);
305	0	}
306
307	0	BN_CTX_free(ctx);
308	0	EC_POINT_free(kG);
309	0	return sig;
310	0	}
311
312		static int sm2_sig_verify(const EC_KEY key, const ECDSA_SIG sig,
313		const BIGNUM *e)
314	0	{
315	0	int ret = 0;
316	0	const EC_GROUP *group = EC_KEY_get0_group(key);
317	0	const BIGNUM *order = EC_GROUP_get0_order(group);
318	0	BN_CTX *ctx = NULL;
319	0	EC_POINT *pt = NULL;
320	0	BIGNUM *t = NULL;
321	0	BIGNUM *x1 = NULL;
322	0	const BIGNUM *r = NULL;
323	0	const BIGNUM *s = NULL;
324	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
325
326	0	ctx = BN_CTX_new_ex(libctx);
327	0	pt = EC_POINT_new(group);
328	0	if (ctx == NULL \|\| pt == NULL) {
329	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
330	0	goto done;
331	0	}
332
333	0	BN_CTX_start(ctx);
334	0	t = BN_CTX_get(ctx);
335	0	x1 = BN_CTX_get(ctx);
336	0	if (x1 == NULL) {
337	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
338	0	goto done;
339	0	}
340
341		/*
342		* B1: verify whether r' in [1,n-1], verification failed if not
343		* B2: verify whether s' in [1,n-1], verification failed if not
344		* B3: set M'~=ZA \|\| M'
345		* B4: calculate e'=Hv(M'~)
346		* B5: calculate t = (r' + s') modn, verification failed if t=0
347		* B6: calculate the point (x1', y1')=[s']G + [t]PA
348		* B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
349		*/
350
351	0	ECDSA_SIG_get0(sig, &r, &s);
352
353	0	if (BN_cmp(r, BN_value_one()) < 0
354	0	\|\| BN_cmp(s, BN_value_one()) < 0
355	0	\|\| BN_cmp(order, r) <= 0
356	0	\|\| BN_cmp(order, s) <= 0) {
357	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
358	0	goto done;
359	0	}
360
361	0	if (!BN_mod_add(t, r, s, order, ctx)) {
362	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
363	0	goto done;
364	0	}
365
366	0	if (BN_is_zero(t)) {
367	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
368	0	goto done;
369	0	}
370
371	0	if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
372	0	\|\| !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
373	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
374	0	goto done;
375	0	}
376
377	0	if (!BN_mod_add(t, e, x1, order, ctx)) {
378	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
379	0	goto done;
380	0	}
381
382	0	if (BN_cmp(r, t) == 0)
383	0	ret = 1;
384
385	0	done:
386	0	EC_POINT_free(pt);
387	0	BN_CTX_free(ctx);
388	0	return ret;
389	0	}
390
391		ECDSA_SIG ossl_sm2_do_sign(const EC_KEY key,
392		const EVP_MD *digest,
393		const uint8_t *id,
394		const size_t id_len,
395		const uint8_t *msg, size_t msg_len)
396	0	{
397	0	BIGNUM *e = NULL;
398	0	ECDSA_SIG *sig = NULL;
399
400	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
401	0	if (e == NULL) {
402		/* SM2err already called */
403	0	goto done;
404	0	}
405
406	0	sig = sm2_sig_gen(key, e);
407
408	0	done:
409	0	BN_free(e);
410	0	return sig;
411	0	}
412
413		int ossl_sm2_do_verify(const EC_KEY *key,
414		const EVP_MD *digest,
415		const ECDSA_SIG *sig,
416		const uint8_t *id,
417		const size_t id_len,
418		const uint8_t *msg, size_t msg_len)
419	0	{
420	0	BIGNUM *e = NULL;
421	0	int ret = 0;
422
423	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
424	0	if (e == NULL) {
425		/* SM2err already called */
426	0	goto done;
427	0	}
428
429	0	ret = sm2_sig_verify(key, sig, e);
430
431	0	done:
432	0	BN_free(e);
433	0	return ret;
434	0	}
435
436		int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
437		unsigned char sig, unsigned int siglen,
438		EC_KEY *eckey)
439	0	{
440	0	BIGNUM *e = NULL;
441	0	ECDSA_SIG *s = NULL;
442	0	int sigleni;
443	0	int ret = -1;
444
445	0	e = BN_bin2bn(dgst, dgstlen, NULL);
446	0	if (e == NULL) {
447	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
448	0	goto done;
449	0	}
450
451	0	s = sm2_sig_gen(eckey, e);
452	0	if (s == NULL) {
453	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
454	0	goto done;
455	0	}
456
457	0	sigleni = i2d_ECDSA_SIG(s, sig != NULL ? &sig : NULL);
458	0	if (sigleni < 0) {
459	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
460	0	goto done;
461	0	}
462	0	*siglen = (unsigned int)sigleni;
463
464	0	ret = 1;
465
466	0	done:
467	0	ECDSA_SIG_free(s);
468	0	BN_free(e);
469	0	return ret;
470	0	}
471
472		int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
473		const unsigned char *sig, int sig_len,
474		EC_KEY *eckey)
475	0	{
476	0	ECDSA_SIG *s = NULL;
477	0	BIGNUM *e = NULL;
478	0	const unsigned char *p = sig;
479	0	unsigned char *der = NULL;
480	0	int derlen = -1;
481	0	int ret = -1;
482
483	0	s = ECDSA_SIG_new();
484	0	if (s == NULL) {
485	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
486	0	goto done;
487	0	}
488	0	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
489	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
490	0	goto done;
491	0	}
492		/* Ensure signature uses DER and doesn't have trailing garbage */
493	0	derlen = i2d_ECDSA_SIG(s, &der);
494	0	if (derlen != sig_len \|\| memcmp(sig, der, derlen) != 0) {
495	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
496	0	goto done;
497	0	}
498
499	0	e = BN_bin2bn(dgst, dgstlen, NULL);
500	0	if (e == NULL) {
501	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
502	0	goto done;
503	0	}
504
505	0	ret = sm2_sig_verify(eckey, s, e);
506
507	0	done:
508	0	OPENSSL_free(der);
509	0	BN_free(e);
510	0	ECDSA_SIG_free(s);
511	0	return ret;
512	0	}