74 lines
2.3 KiB
C
74 lines
2.3 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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* Copyright (C) 2009 Andreas Steffen - Hochschule fuer Technik Rapperswil
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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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#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 <library.h>
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#include <crypto/rngs/rng.h>
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#include "constants.h"
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#include "defs.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 get_cookie(bool initiator, u_int8_t *cookie, int length, ip_address *addr)
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{
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hasher_t *hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
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u_char buffer[HASH_SIZE_SHA1];
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do {
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if (initiator)
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{
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rng_t *rng;
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rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
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rng->get_bytes(rng, length, cookie);
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rng->destroy(rng);
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}
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else /* Responder cookie */
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{
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chunk_t addr_chunk, secret_chunk, counter_chunk;
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size_t addr_len;
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static u_int32_t counter = 0;
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unsigned char addr_buf[
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sizeof(union {struct in_addr A; struct in6_addr B;})];
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addr_len = addrbytesof(addr, addr_buf, sizeof(addr_buf));
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addr_chunk = chunk_create(addr_buf, addr_len);
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secret_chunk = chunk_create(secret_of_the_day, HASH_SIZE_SHA1);
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counter++;
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counter_chunk = chunk_create((void *) &counter, sizeof(counter));
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hasher->get_hash(hasher, addr_chunk, NULL);
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hasher->get_hash(hasher, secret_chunk, NULL);
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hasher->get_hash(hasher, counter_chunk, buffer);
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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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hasher->destroy(hasher);
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}
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