ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
EC_KEY *eckey)
{
int ok = 0, i;
BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL;
const BIGNUM *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
const BIGNUM *priv_key;
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
ret = ECDSA_SIG_new();
if (ret == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, 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) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_GROUP_get_order(group, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_EC_LIB);
goto err;
}
i = BN_num_bits(order);
/*
* Need to truncate digest if it is too long: first truncate whole bytes.
*/
if (8 * dgst_len > i)
dgst_len = (i + 7) / 8;
if (!BN_bin2bn(dgst, dgst_len, m)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
/* If still too long truncate remaining bits with a shift */
if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
do {
if (in_kinv == NULL || in_r == NULL) {
if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
} else {
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE);
goto err;
}
}
if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add_quick(s, tmp, m, order)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s)) {
/*
* if kinv and r have been supplied by the caller don't to
* generate new kinv and r values
*/
if (in_kinv != NULL && in_r != NULL) {
ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, EC_R_NEED_NEW_SETUP_VALUES);
goto err;
}
} else
/* s != 0 => we have a valid signature */
break;
}
while (1);
ok = 1;
err:
if (!ok) {
ECDSA_SIG_free(ret);
ret = NULL;
}
BN_CTX_free(ctx);
BN_clear_free(m);
BN_clear_free(tmp);
BN_free(order);
BN_clear_free(kinv);
return ret;
}
int ossl_ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp)
{
return ecdsa_sign_setup(eckey, ctx_in, kinvp, rp, NULL, 0);
}
ECDSA_SIG *ECDSA_do_sign_ex(const uint8_t *digest, size_t digest_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
const EC_KEY *eckey) {
int ok = 0;
BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL;
const BIGNUM *ckinv;
BN_CTX *ctx = NULL;
const EC_GROUP *group;
ECDSA_SIG *ret;
const BIGNUM *priv_key;
if (eckey->ecdsa_meth && eckey->ecdsa_meth->sign) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NOT_IMPLEMENTED);
return NULL;
}
group = EC_KEY_get0_group(eckey);
priv_key = EC_KEY_get0_private_key(eckey);
if (group == NULL || priv_key == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_PASSED_NULL_PARAMETER);
return NULL;
}
ret = ECDSA_SIG_new();
if (!ret) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
return NULL;
}
s = ret->s;
if ((ctx = BN_CTX_new()) == NULL ||
(tmp = BN_new()) == NULL ||
(m = BN_new()) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
const BIGNUM *order = EC_GROUP_get0_order(group);
if (!digest_to_bn(m, digest, digest_len, order)) {
goto err;
}
for (;;) {
if (in_kinv == NULL || in_r == NULL) {
if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, digest, digest_len)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_ECDSA_LIB);
goto err;
}
ckinv = kinv;
} else {
ckinv = in_kinv;
if (BN_copy(ret->r, in_r) == NULL) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_MALLOC_FAILURE);
goto err;
}
}
if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_add_quick(s, tmp, m, order)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
OPENSSL_PUT_ERROR(ECDSA, ERR_R_BN_LIB);
goto err;
}
if (BN_is_zero(s)) {
// if kinv and r have been supplied by the caller
// don't to generate new kinv and r values
if (in_kinv != NULL && in_r != NULL) {
OPENSSL_PUT_ERROR(ECDSA, ECDSA_R_NEED_NEW_SETUP_VALUES);
goto err;
}
} else {
// s != 0 => we have a valid signature
break;
}
}
ok = 1;
err:
if (!ok) {
ECDSA_SIG_free(ret);
ret = NULL;
}
BN_CTX_free(ctx);
BN_clear_free(m);
BN_clear_free(tmp);
BN_clear_free(kinv);
return ret;
}
static int ecdsa_sign_setup_no_digest(EC_KEY *eckey,
BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) {
return ecdsa_sign_setup(eckey, ctx_in, kinvp, rp, NULL, 0);
}
int ECDSA_sign_setup(const EC_KEY *eckey, BN_CTX *ctx, BIGNUM **kinv,
BIGNUM **rp) {
return ecdsa_sign_setup(eckey, ctx, kinv, rp, NULL, 0);
}
