122 lines
4 KiB
C
122 lines
4 KiB
C
/* crypto/ec/ec_check.c */
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/* ====================================================================
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* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* openssl-core@openssl.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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* ====================================================================
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*
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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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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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BIGNUM *order;
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BN_CTX *new_ctx = NULL;
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EC_POINT *point = NULL;
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if (ctx == NULL)
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{
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ctx = new_ctx = BN_CTX_new();
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if (ctx == NULL)
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{
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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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BN_CTX_start(ctx);
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if ((order = BN_CTX_get(ctx)) == NULL) goto err;
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/* check the discriminant */
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if (!EC_GROUP_check_discriminant(group, ctx))
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{
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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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{
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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))
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{
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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) goto err;
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if (!EC_GROUP_get_order(group, order, ctx)) goto err;
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if (BN_is_zero(order))
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{
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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)) goto err;
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if (!EC_POINT_is_at_infinity(group, point))
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{
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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_end(ctx);
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if (new_ctx != NULL)
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BN_CTX_free(new_ctx);
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if (point)
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EC_POINT_free(point);
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return ret;
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}
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