68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
/* cookie generation/verification routines.
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* Copyright (C) 1997 Angelos D. Keromytis.
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* Copyright (C) 1998-2002 D. Hugh Redelmeier.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* RCSID $Id$
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*/
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <freeswan.h>
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#include "constants.h"
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#include "defs.h"
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#include "sha1.h"
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#include "rnd.h"
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#include "cookie.h"
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const u_char zero_cookie[COOKIE_SIZE]; /* guaranteed 0 */
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/* Generate a cookie.
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* First argument is true if we're to create an Initiator cookie.
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* Length SHOULD be a multiple of sizeof(u_int32_t).
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*/
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void
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get_cookie(bool initiator, u_int8_t *cookie, int length, const ip_address *addr)
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{
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u_char buffer[SHA1_DIGEST_SIZE];
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SHA1_CTX ctx;
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do {
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if (initiator)
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{
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get_rnd_bytes(cookie, length);
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}
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else /* Responder cookie */
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{
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/* This looks as good as any way */
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size_t addr_length;
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static u_int32_t counter = 0;
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unsigned char addr_buff[
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sizeof(union {struct in_addr A; struct in6_addr B;})];
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addr_length = addrbytesof(addr, addr_buff, sizeof(addr_buff));
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SHA1Init(&ctx);
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SHA1Update(&ctx, addr_buff, addr_length);
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SHA1Update(&ctx, secret_of_the_day, sizeof(secret_of_the_day));
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counter++;
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SHA1Update(&ctx, (const void *) &counter, sizeof(counter));
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SHA1Final(buffer, &ctx);
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memcpy(cookie, buffer, length);
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}
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} while (is_zero_cookie(cookie)); /* probably never loops */
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}
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