#include "ecs_locl.h"
#include <openssl/err.h>
#include <openssl/obj_mac.h>
#include <openssl/bn.h>
static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen,
const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey);
static ECDSA_METHOD openssl_ecdsa_meth = {
"OpenSSL ECDSA method",
ecdsa_do_sign,
ecdsa_sign_setup,
ecdsa_do_verify,
#if 0
NULL,
NULL,
#endif
0,
NULL
};
const ECDSA_METHOD *ECDSA_OpenSSL(void)
{
return &openssl_ecdsa_meth;
}
static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp)
{
BN_CTX *ctx = NULL;
BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
EC_POINT *tmp_point=NULL;
const EC_GROUP *group;
int ret = 0;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (ctx_in == NULL)
{
if ((ctx = BN_CTX_new()) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_MALLOC_FAILURE);
return 0;
}
}
else
ctx = ctx_in;
k = BN_new();
r = BN_new();
order = BN_new();
X = BN_new();
if (!k || !r || !order || !X)
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
goto err;
}
if ((tmp_point = EC_POINT_new(group)) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
do
{
do
if (!BN_rand_range(k, order))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
goto err;
}
while (BN_is_zero(k));
if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
{
if (!EC_POINT_get_affine_coordinates_GFp(group,
tmp_point, X, NULL, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
goto err;
}
}
else
{
if (!EC_POINT_get_affine_coordinates_GF2m(group,
tmp_point, X, NULL, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,ERR_R_EC_LIB);
goto err;
}
}
if (!BN_nnmod(r, X, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
}
while (BN_is_zero(r));
if (!BN_mod_inverse(k, k, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
goto err;
}
if (*rp != NULL)
BN_clear_free(*rp);
if (*kinvp != NULL)
BN_clear_free(*kinvp);
*rp = r;
*kinvp = k;
ret = 1;
err:
if (!ret)
{
if (k != NULL) BN_clear_free(k);
if (r != NULL) BN_clear_free(r);
}
if (ctx_in == NULL)
BN_CTX_free(ctx);
if (order != NULL)
BN_free(order);
if (tmp_point != NULL)
EC_POINT_free(tmp_point);
if (X)
BN_clear_free(X);
return(ret);
}
static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r, EC_KEY *eckey)
{
int ok = 0;
BIGNUM *kinv=NULL, *s, *m=NULL,*tmp=NULL,*order=NULL;
const BIGNUM *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
ECDSA_DATA *ecdsa;
const BIGNUM *priv_key;
ecdsa = ecdsa_check(eckey);
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL || ecdsa == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
ret = ECDSA_SIG_new();
if (!ret)
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
return NULL;
}
s = ret->s;
if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
(tmp = BN_new()) == NULL || (m = BN_new()) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB);
goto err;
}
if (8 * dgst_len > BN_num_bits(order))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,
ECDSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
goto err;
}
if (!BN_bin2bn(dgst, dgst_len, m))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
goto err;
}
do
{
if (in_kinv == NULL || in_r == NULL)
{
if (!ECDSA_sign_setup(eckey, ctx, &kinv, &ret->r))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
}
else
{
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
}
if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add_quick(s, tmp, m, order))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s))
{
if (in_kinv != NULL && in_r != NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ECDSA_R_NEED_NEW_SETUP_VALUES);
goto err;
}
}
else
break;
}
while (1);
ok = 1;
err:
if (!ok)
{
ECDSA_SIG_free(ret);
ret = NULL;
}
if (ctx)
BN_CTX_free(ctx);
if (m)
BN_clear_free(m);
if (tmp)
BN_clear_free(tmp);
if (order)
BN_free(order);
if (kinv)
BN_clear_free(kinv);
return ret;
}
static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey)
{
int ret = -1;
BN_CTX *ctx;
BIGNUM *order, *u1, *u2, *m, *X;
EC_POINT *point = NULL;
const EC_GROUP *group;
const EC_POINT *pub_key;
if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
(pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS);
return -1;
}
ctx = BN_CTX_new();
if (!ctx)
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
return -1;
}
BN_CTX_start(ctx);
order = BN_CTX_get(ctx);
u1 = BN_CTX_get(ctx);
u2 = BN_CTX_get(ctx);
m = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
if (!X)
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
goto err;
}
if (8 * dgst_len > BN_num_bits(order))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY,
ECDSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
ret = 0;
goto err;
}
if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0)
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_BAD_SIGNATURE);
ret = 0;
goto err;
}
if (!BN_mod_inverse(u2, sig->s, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
if (!BN_bin2bn(dgst, dgst_len, m))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(u1, m, u2, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(u2, sig->r, u2, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
if ((point = EC_POINT_new(group)) == NULL)
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
goto err;
}
if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) == NID_X9_62_prime_field)
{
if (!EC_POINT_get_affine_coordinates_GFp(group,
point, X, NULL, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
goto err;
}
}
else
{
if (!EC_POINT_get_affine_coordinates_GF2m(group,
point, X, NULL, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
goto err;
}
}
if (!BN_nnmod(u1, X, order, ctx))
{
ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
goto err;
}
ret = (BN_ucmp(u1, sig->r) == 0);
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
if (point)
EC_POINT_free(point);
return ret;
}