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/*
* Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (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 "ec_lcl.h"
#include <openssl/err.h>
int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
{
int ret = 0;
const BIGNUM *order;
BN_CTX *new_ctx = NULL;
EC_POINT *point = NULL;
/* Custom curves assumed to be correct */
if ((group->meth->flags & EC_FLAGS_CUSTOM_CURVE) != 0)
return 1;
if (ctx == NULL) {
ctx = new_ctx = BN_CTX_new();
if (ctx == NULL) {
ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
goto err;
}
}
/* check the discriminant */
if (!EC_GROUP_check_discriminant(group, ctx)) {
ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
goto err;
}
/* check the generator */
if (group->generator == NULL) {
ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
goto err;
}
if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) {
ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
goto err;
}
/* check the order of the generator */
if ((point = EC_POINT_new(group)) == NULL)
goto err;
order = EC_GROUP_get0_order(group);
if (order == NULL)
goto err;
if (BN_is_zero(order)) {
ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
goto err;
}
if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx))
goto err;
if (!EC_POINT_is_at_infinity(group, point)) {
ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
goto err;
}
ret = 1;
err:
BN_CTX_free(new_ctx);
EC_POINT_free(point);
return ret;
}
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