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73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
/*
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* Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include "ec_lcl.h"
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#include <openssl/err.h>
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int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
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{
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int ret = 0;
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const BIGNUM *order;
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BN_CTX *new_ctx = NULL;
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EC_POINT *point = NULL;
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/* Custom curves assumed to be correct */
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if ((group->meth->flags & EC_FLAGS_CUSTOM_CURVE) != 0)
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return 1;
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if (ctx == NULL) {
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL) {
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ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
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goto err;
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}
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}
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/* check the discriminant */
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if (!EC_GROUP_check_discriminant(group, ctx)) {
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ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
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goto err;
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}
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/* check the generator */
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if (group->generator == NULL) {
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ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
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goto err;
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}
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if (EC_POINT_is_on_curve(group, group->generator, ctx) <= 0) {
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ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
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goto err;
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}
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/* check the order of the generator */
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if ((point = EC_POINT_new(group)) == NULL)
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goto err;
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order = EC_GROUP_get0_order(group);
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if (order == NULL)
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goto err;
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if (BN_is_zero(order)) {
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ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
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goto err;
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}
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if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx))
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goto err;
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if (!EC_POINT_is_at_infinity(group, point)) {
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ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
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goto err;
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}
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ret = 1;
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err:
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BN_CTX_free(new_ctx);
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EC_POINT_free(point);
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return ret;
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}
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