/src/openssl31/crypto/sm2/sm2_sign.c

Source (jump to first uncovered line)
/*
 * Copyright 2017-2024 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();
    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,
                                                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;
    }

    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;

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

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

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

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

    ret = 1;

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

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

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

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

    ret = sm2_sig_verify(eckey, s, e);

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

Coverage Report

Created: 2024-07-27 06:39

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright 2017-2024 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	ctx = BN_CTX_new_ex(ossl_ec_key_get_libctx(key));
54	0	if (hash == NULL \|\| ctx == NULL) {
55	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
56	0	goto done;
57	0	}
58
59	0	p = BN_CTX_get(ctx);
60	0	a = BN_CTX_get(ctx);
61	0	b = BN_CTX_get(ctx);
62	0	xG = BN_CTX_get(ctx);
63	0	yG = BN_CTX_get(ctx);
64	0	xA = BN_CTX_get(ctx);
65	0	yA = BN_CTX_get(ctx);
66
67	0	if (yA == NULL) {
68	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
69	0	goto done;
70	0	}
71
72	0	if (!EVP_DigestInit(hash, digest)) {
73	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
74	0	goto done;
75	0	}
76
77		/* Z = h(ENTL \|\| ID \|\| a \|\| b \|\| xG \|\| yG \|\| xA \|\| yA) */
78
79	0	if (id_len >= (UINT16_MAX / 8)) {
80		/* too large */
81	0	ERR_raise(ERR_LIB_SM2, SM2_R_ID_TOO_LARGE);
82	0	goto done;
83	0	}
84
85	0	entl = (uint16_t)(8 * id_len);
86
87	0	e_byte = entl >> 8;
88	0	if (!EVP_DigestUpdate(hash, &e_byte, 1)) {
89	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
90	0	goto done;
91	0	}
92	0	e_byte = entl & 0xFF;
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
98	0	if (id_len > 0 && !EVP_DigestUpdate(hash, id, id_len)) {
99	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
100	0	goto done;
101	0	}
102
103	0	if (!EC_GROUP_get_curve(group, p, a, b, ctx)) {
104	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
105	0	goto done;
106	0	}
107
108	0	p_bytes = BN_num_bytes(p);
109	0	buf = OPENSSL_zalloc(p_bytes);
110	0	if (buf == NULL) {
111	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
112	0	goto done;
113	0	}
114
115	0	if (BN_bn2binpad(a, buf, p_bytes) < 0
116	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
117	0	\|\| BN_bn2binpad(b, buf, p_bytes) < 0
118	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
119	0	\|\| !EC_POINT_get_affine_coordinates(group,
120	0	EC_GROUP_get0_generator(group),
121	0	xG, yG, ctx)
122	0	\|\| BN_bn2binpad(xG, buf, p_bytes) < 0
123	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
124	0	\|\| BN_bn2binpad(yG, buf, p_bytes) < 0
125	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
126	0	\|\| !EC_POINT_get_affine_coordinates(group,
127	0	pubkey,
128	0	xA, yA, ctx)
129	0	\|\| BN_bn2binpad(xA, buf, p_bytes) < 0
130	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
131	0	\|\| BN_bn2binpad(yA, buf, p_bytes) < 0
132	0	\|\| !EVP_DigestUpdate(hash, buf, p_bytes)
133	0	\|\| !EVP_DigestFinal(hash, out, NULL)) {
134	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
135	0	goto done;
136	0	}
137
138	0	rc = 1;
139
140	0	done:
141	0	OPENSSL_free(buf);
142	0	BN_CTX_free(ctx);
143	0	EVP_MD_CTX_free(hash);
144	0	return rc;
145	0	}
146
147		static BIGNUM sm2_compute_msg_hash(const EVP_MD digest,
148		const EC_KEY *key,
149		const uint8_t *id,
150		const size_t id_len,
151		const uint8_t *msg, size_t msg_len)
152	0	{
153	0	EVP_MD_CTX *hash = EVP_MD_CTX_new();
154	0	const int md_size = EVP_MD_get_size(digest);
155	0	uint8_t *z = NULL;
156	0	BIGNUM *e = NULL;
157	0	EVP_MD *fetched_digest = NULL;
158	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
159	0	const char *propq = ossl_ec_key_get0_propq(key);
160
161	0	if (md_size < 0) {
162	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_DIGEST);
163	0	goto done;
164	0	}
165
166	0	z = OPENSSL_zalloc(md_size);
167	0	if (hash == NULL \|\| z == NULL) {
168	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
169	0	goto done;
170	0	}
171
172	0	fetched_digest = EVP_MD_fetch(libctx, EVP_MD_get0_name(digest), propq);
173	0	if (fetched_digest == NULL) {
174	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
175	0	goto done;
176	0	}
177
178	0	if (!ossl_sm2_compute_z_digest(z, fetched_digest, id, id_len, key)) {
179		/* SM2err already called */
180	0	goto done;
181	0	}
182
183	0	if (!EVP_DigestInit(hash, fetched_digest)
184	0	\|\| !EVP_DigestUpdate(hash, z, md_size)
185	0	\|\| !EVP_DigestUpdate(hash, msg, msg_len)
186		/* reuse z buffer to hold H(Z \|\| M) */
187	0	\|\| !EVP_DigestFinal(hash, z, NULL)) {
188	0	ERR_raise(ERR_LIB_SM2, ERR_R_EVP_LIB);
189	0	goto done;
190	0	}
191
192	0	e = BN_bin2bn(z, md_size, NULL);
193	0	if (e == NULL)
194	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
195
196	0	done:
197	0	EVP_MD_free(fetched_digest);
198	0	OPENSSL_free(z);
199	0	EVP_MD_CTX_free(hash);
200	0	return e;
201	0	}
202
203		static ECDSA_SIG sm2_sig_gen(const EC_KEY key, const BIGNUM *e)
204	0	{
205	0	const BIGNUM *dA = EC_KEY_get0_private_key(key);
206	0	const EC_GROUP *group = EC_KEY_get0_group(key);
207	0	const BIGNUM *order = EC_GROUP_get0_order(group);
208	0	ECDSA_SIG *sig = NULL;
209	0	EC_POINT *kG = NULL;
210	0	BN_CTX *ctx = NULL;
211	0	BIGNUM *k = NULL;
212	0	BIGNUM *rk = NULL;
213	0	BIGNUM *r = NULL;
214	0	BIGNUM *s = NULL;
215	0	BIGNUM *x1 = NULL;
216	0	BIGNUM *tmp = NULL;
217	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
218
219	0	kG = EC_POINT_new(group);
220	0	ctx = BN_CTX_new_ex(libctx);
221	0	if (kG == NULL \|\| ctx == NULL) {
222	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
223	0	goto done;
224	0	}
225
226	0	BN_CTX_start(ctx);
227	0	k = BN_CTX_get(ctx);
228	0	rk = BN_CTX_get(ctx);
229	0	x1 = BN_CTX_get(ctx);
230	0	tmp = BN_CTX_get(ctx);
231	0	if (tmp == NULL) {
232	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
233	0	goto done;
234	0	}
235
236		/*
237		* These values are returned and so should not be allocated out of the
238		* context
239		*/
240	0	r = BN_new();
241	0	s = BN_new();
242
243	0	if (r == NULL \|\| s == NULL) {
244	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
245	0	goto done;
246	0	}
247
248		/*
249		* A3: Generate a random number k in [1,n-1] using random number generators;
250		* A4: Compute (x1,y1)=[k]G, and convert the type of data x1 to be integer
251		* as specified in clause 4.2.8 of GM/T 0003.1-2012;
252		* A5: Compute r=(e+x1) mod n. If r=0 or r+k=n, then go to A3;
253		* A6: Compute s=(1/(1+dA)(k-rdA)) mod n. If s=0, then go to A3;
254		* A7: Convert the type of data (r,s) to be bit strings according to the details
255		* in clause 4.2.2 of GM/T 0003.1-2012. Then the signature of message M is (r,s).
256		*/
257	0	for (;;) {
258	0	if (!BN_priv_rand_range_ex(k, order, 0, ctx)) {
259	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
260	0	goto done;
261	0	}
262
263	0	if (!EC_POINT_mul(group, kG, k, NULL, NULL, ctx)
264	0	\|\| !EC_POINT_get_affine_coordinates(group, kG, x1, NULL,
265	0	ctx)
266	0	\|\| !BN_mod_add(r, e, x1, order, ctx)) {
267	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
268	0	goto done;
269	0	}
270
271		/* try again if r == 0 or r+k == n */
272	0	if (BN_is_zero(r))
273	0	continue;
274
275	0	if (!BN_add(rk, r, k)) {
276	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
277	0	goto done;
278	0	}
279
280	0	if (BN_cmp(rk, order) == 0)
281	0	continue;
282
283	0	if (!BN_add(s, dA, BN_value_one())
284	0	\|\| !ossl_ec_group_do_inverse_ord(group, s, s, ctx)
285	0	\|\| !BN_mod_mul(tmp, dA, r, order, ctx)
286	0	\|\| !BN_sub(tmp, k, tmp)
287	0	\|\| !BN_mod_mul(s, s, tmp, order, ctx)) {
288	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
289	0	goto done;
290	0	}
291
292		/* try again if s == 0 */
293	0	if (BN_is_zero(s))
294	0	continue;
295
296	0	sig = ECDSA_SIG_new();
297	0	if (sig == NULL) {
298	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
299	0	goto done;
300	0	}
301
302		/* takes ownership of r and s */
303	0	ECDSA_SIG_set0(sig, r, s);
304	0	break;
305	0	}
306
307	0	done:
308	0	if (sig == NULL) {
309	0	BN_free(r);
310	0	BN_free(s);
311	0	}
312
313	0	BN_CTX_free(ctx);
314	0	EC_POINT_free(kG);
315	0	return sig;
316	0	}
317
318		static int sm2_sig_verify(const EC_KEY key, const ECDSA_SIG sig,
319		const BIGNUM *e)
320	0	{
321	0	int ret = 0;
322	0	const EC_GROUP *group = EC_KEY_get0_group(key);
323	0	const BIGNUM *order = EC_GROUP_get0_order(group);
324	0	BN_CTX *ctx = NULL;
325	0	EC_POINT *pt = NULL;
326	0	BIGNUM *t = NULL;
327	0	BIGNUM *x1 = NULL;
328	0	const BIGNUM *r = NULL;
329	0	const BIGNUM *s = NULL;
330	0	OSSL_LIB_CTX *libctx = ossl_ec_key_get_libctx(key);
331
332	0	ctx = BN_CTX_new_ex(libctx);
333	0	pt = EC_POINT_new(group);
334	0	if (ctx == NULL \|\| pt == NULL) {
335	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
336	0	goto done;
337	0	}
338
339	0	BN_CTX_start(ctx);
340	0	t = BN_CTX_get(ctx);
341	0	x1 = BN_CTX_get(ctx);
342	0	if (x1 == NULL) {
343	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
344	0	goto done;
345	0	}
346
347		/*
348		* B1: verify whether r' in [1,n-1], verification failed if not
349		* B2: verify whether s' in [1,n-1], verification failed if not
350		* B3: set M'~=ZA \|\| M'
351		* B4: calculate e'=Hv(M'~)
352		* B5: calculate t = (r' + s') modn, verification failed if t=0
353		* B6: calculate the point (x1', y1')=[s']G + [t]PA
354		* B7: calculate R=(e'+x1') modn, verification pass if yes, otherwise failed
355		*/
356
357	0	ECDSA_SIG_get0(sig, &r, &s);
358
359	0	if (BN_cmp(r, BN_value_one()) < 0
360	0	\|\| BN_cmp(s, BN_value_one()) < 0
361	0	\|\| BN_cmp(order, r) <= 0
362	0	\|\| BN_cmp(order, s) <= 0) {
363	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
364	0	goto done;
365	0	}
366
367	0	if (!BN_mod_add(t, r, s, order, ctx)) {
368	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
369	0	goto done;
370	0	}
371
372	0	if (BN_is_zero(t)) {
373	0	ERR_raise(ERR_LIB_SM2, SM2_R_BAD_SIGNATURE);
374	0	goto done;
375	0	}
376
377	0	if (!EC_POINT_mul(group, pt, s, EC_KEY_get0_public_key(key), t, ctx)
378	0	\|\| !EC_POINT_get_affine_coordinates(group, pt, x1, NULL, ctx)) {
379	0	ERR_raise(ERR_LIB_SM2, ERR_R_EC_LIB);
380	0	goto done;
381	0	}
382
383	0	if (!BN_mod_add(t, e, x1, order, ctx)) {
384	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
385	0	goto done;
386	0	}
387
388	0	if (BN_cmp(r, t) == 0)
389	0	ret = 1;
390
391	0	done:
392	0	EC_POINT_free(pt);
393	0	BN_CTX_free(ctx);
394	0	return ret;
395	0	}
396
397		ECDSA_SIG ossl_sm2_do_sign(const EC_KEY key,
398		const EVP_MD *digest,
399		const uint8_t *id,
400		const size_t id_len,
401		const uint8_t *msg, size_t msg_len)
402	0	{
403	0	BIGNUM *e = NULL;
404	0	ECDSA_SIG *sig = NULL;
405
406	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
407	0	if (e == NULL) {
408		/* SM2err already called */
409	0	goto done;
410	0	}
411
412	0	sig = sm2_sig_gen(key, e);
413
414	0	done:
415	0	BN_free(e);
416	0	return sig;
417	0	}
418
419		int ossl_sm2_do_verify(const EC_KEY *key,
420		const EVP_MD *digest,
421		const ECDSA_SIG *sig,
422		const uint8_t *id,
423		const size_t id_len,
424		const uint8_t *msg, size_t msg_len)
425	0	{
426	0	BIGNUM *e = NULL;
427	0	int ret = 0;
428
429	0	e = sm2_compute_msg_hash(digest, key, id, id_len, msg, msg_len);
430	0	if (e == NULL) {
431		/* SM2err already called */
432	0	goto done;
433	0	}
434
435	0	ret = sm2_sig_verify(key, sig, e);
436
437	0	done:
438	0	BN_free(e);
439	0	return ret;
440	0	}
441
442		int ossl_sm2_internal_sign(const unsigned char *dgst, int dgstlen,
443		unsigned char sig, unsigned int siglen,
444		EC_KEY *eckey)
445	0	{
446	0	BIGNUM *e = NULL;
447	0	ECDSA_SIG *s = NULL;
448	0	int sigleni;
449	0	int ret = -1;
450
451	0	if (sig == NULL) {
452	0	ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);
453	0	goto done;
454	0	}
455
456	0	e = BN_bin2bn(dgst, dgstlen, NULL);
457	0	if (e == NULL) {
458	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
459	0	goto done;
460	0	}
461
462	0	s = sm2_sig_gen(eckey, e);
463	0	if (s == NULL) {
464	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
465	0	goto done;
466	0	}
467
468	0	sigleni = i2d_ECDSA_SIG(s, &sig);
469	0	if (sigleni < 0) {
470	0	ERR_raise(ERR_LIB_SM2, ERR_R_INTERNAL_ERROR);
471	0	goto done;
472	0	}
473	0	*siglen = (unsigned int)sigleni;
474
475	0	ret = 1;
476
477	0	done:
478	0	ECDSA_SIG_free(s);
479	0	BN_free(e);
480	0	return ret;
481	0	}
482
483		int ossl_sm2_internal_verify(const unsigned char *dgst, int dgstlen,
484		const unsigned char *sig, int sig_len,
485		EC_KEY *eckey)
486	0	{
487	0	ECDSA_SIG *s = NULL;
488	0	BIGNUM *e = NULL;
489	0	const unsigned char *p = sig;
490	0	unsigned char *der = NULL;
491	0	int derlen = -1;
492	0	int ret = -1;
493
494	0	s = ECDSA_SIG_new();
495	0	if (s == NULL) {
496	0	ERR_raise(ERR_LIB_SM2, ERR_R_MALLOC_FAILURE);
497	0	goto done;
498	0	}
499	0	if (d2i_ECDSA_SIG(&s, &p, sig_len) == NULL) {
500	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
501	0	goto done;
502	0	}
503		/* Ensure signature uses DER and doesn't have trailing garbage */
504	0	derlen = i2d_ECDSA_SIG(s, &der);
505	0	if (derlen != sig_len \|\| memcmp(sig, der, derlen) != 0) {
506	0	ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_ENCODING);
507	0	goto done;
508	0	}
509
510	0	e = BN_bin2bn(dgst, dgstlen, NULL);
511	0	if (e == NULL) {
512	0	ERR_raise(ERR_LIB_SM2, ERR_R_BN_LIB);
513	0	goto done;
514	0	}
515
516	0	ret = sm2_sig_verify(eckey, s, e);
517
518	0	done:
519	0	OPENSSL_free(der);
520	0	BN_free(e);
521	0	ECDSA_SIG_free(s);
522	0	return ret;
523	0	}