/*

 * Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * 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" /* to be able to use EC_KEY and EC_GROUP */

#include <openssl/err.h>

#include "crypto/sm2err.h"

#include "crypto/sm2.h"

#include <openssl/ec.h> /* EC_KEY and EC_GROUP functions */

/*

 * SM2 key generation is implemented within ec_generate_key() in

 * crypto/ec/ec_key.c

 */

int ossl_sm2_key_private_check(const EC_KEY *eckey)

{

    int ret = 0;

    BIGNUM *max = NULL;

    const EC_GROUP *group = NULL;

    const BIGNUM *priv_key = NULL, *order = NULL;

    if (eckey == NULL

            || (group = EC_KEY_get0_group(eckey)) == NULL

            || (priv_key = EC_KEY_get0_private_key(eckey)) == NULL

            || (order = EC_GROUP_get0_order(group)) == NULL) {

        ERR_raise(ERR_LIB_SM2, ERR_R_PASSED_NULL_PARAMETER);

        return 0;

    }

    /* range of SM2 private key is [1, n-1) */

    max = BN_dup(order);

    if (max == NULL || !BN_sub_word(max, 1))

        goto end;

    if (BN_cmp(priv_key, BN_value_one()) < 0

        || BN_cmp(priv_key, max) >= 0) {

        ERR_raise(ERR_LIB_SM2, SM2_R_INVALID_PRIVATE_KEY);

        goto end;

    }

    ret = 1;

 end:

    BN_free(max);

    return ret;

}