121 lines
4.3 KiB
C
121 lines
4.3 KiB
C
/* crypto/dh/dh_check.c */
|
|
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
|
|
* All rights reserved.
|
|
*
|
|
* This package is an SSL implementation written
|
|
* by Eric Young (eay@cryptsoft.com).
|
|
* The implementation was written so as to conform with Netscapes SSL.
|
|
*
|
|
* This library is free for commercial and non-commercial use as long as
|
|
* the following conditions are aheared to. The following conditions
|
|
* apply to all code found in this distribution, be it the RC4, RSA,
|
|
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
|
|
* included with this distribution is covered by the same copyright terms
|
|
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
|
|
*
|
|
* Copyright remains Eric Young's, and as such any Copyright notices in
|
|
* the code are not to be removed.
|
|
* If this package is used in a product, Eric Young should be given attribution
|
|
* as the author of the parts of the library used.
|
|
* This can be in the form of a textual message at program startup or
|
|
* in documentation (online or textual) provided with the package.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* "This product includes cryptographic software written by
|
|
* Eric Young (eay@cryptsoft.com)"
|
|
* The word 'cryptographic' can be left out if the rouines from the library
|
|
* being used are not cryptographic related :-).
|
|
* 4. If you include any Windows specific code (or a derivative thereof) from
|
|
* the apps directory (application code) you must include an acknowledgement:
|
|
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* The licence and distribution terms for any publically available version or
|
|
* derivative of this code cannot be changed. i.e. this code cannot simply be
|
|
* copied and put under another distribution licence
|
|
* [including the GNU Public Licence.]
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include "cryptlib.h"
|
|
#include <openssl/bn.h>
|
|
#include <openssl/dh.h>
|
|
|
|
/* Check that p is a safe prime and
|
|
* if g is 2, 3 or 5, check that is is a suitable generator
|
|
* where
|
|
* for 2, p mod 24 == 11
|
|
* for 3, p mod 12 == 5
|
|
* for 5, p mod 10 == 3 or 7
|
|
* should hold.
|
|
*/
|
|
|
|
int DH_check(DH *dh, int *ret)
|
|
{
|
|
int ok=0;
|
|
BN_CTX *ctx=NULL;
|
|
BN_ULONG l;
|
|
BIGNUM *q=NULL;
|
|
|
|
*ret=0;
|
|
ctx=BN_CTX_new();
|
|
if (ctx == NULL) goto err;
|
|
q=BN_new();
|
|
if (q == NULL) goto err;
|
|
|
|
if (BN_is_word(dh->g,DH_GENERATOR_2))
|
|
{
|
|
l=BN_mod_word(dh->p,24);
|
|
if (l != 11) *ret|=DH_NOT_SUITABLE_GENERATOR;
|
|
}
|
|
#if 0
|
|
else if (BN_is_word(dh->g,DH_GENERATOR_3))
|
|
{
|
|
l=BN_mod_word(dh->p,12);
|
|
if (l != 5) *ret|=DH_NOT_SUITABLE_GENERATOR;
|
|
}
|
|
#endif
|
|
else if (BN_is_word(dh->g,DH_GENERATOR_5))
|
|
{
|
|
l=BN_mod_word(dh->p,10);
|
|
if ((l != 3) && (l != 7))
|
|
*ret|=DH_NOT_SUITABLE_GENERATOR;
|
|
}
|
|
else
|
|
*ret|=DH_UNABLE_TO_CHECK_GENERATOR;
|
|
|
|
if (!BN_is_prime(dh->p,BN_prime_checks,NULL,ctx,NULL))
|
|
*ret|=DH_CHECK_P_NOT_PRIME;
|
|
else
|
|
{
|
|
if (!BN_rshift1(q,dh->p)) goto err;
|
|
if (!BN_is_prime(q,BN_prime_checks,NULL,ctx,NULL))
|
|
*ret|=DH_CHECK_P_NOT_SAFE_PRIME;
|
|
}
|
|
ok=1;
|
|
err:
|
|
if (ctx != NULL) BN_CTX_free(ctx);
|
|
if (q != NULL) BN_free(q);
|
|
return(ok);
|
|
}
|