74 lines
2.7 KiB
C
74 lines
2.7 KiB
C
/* $OpenBSD: cookie.c,v 1.17 2017/02/03 08:23:46 guenther Exp $ */
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/* $EOM: cookie.c,v 1.21 1999/08/05 15:00:04 niklas Exp $ */
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/*
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* Copyright (c) 1998, 1999 Niklas Hallqvist. 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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* 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* This code was written under funding by Ericsson Radio Systems.
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*/
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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 <stdlib.h>
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#include <string.h>
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#include "cookie.h"
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#include "exchange.h"
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#include "hash.h"
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#include "transport.h"
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#include "util.h"
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#define COOKIE_SECRET_SIZE 16
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/*
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* Generate an anti-clogging token (a protection against an attacker forcing
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* us to keep state for a flood of connection requests) a.k.a. a cookie
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* at BUF, LEN bytes long. The cookie will be generated by hashing of
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* information found, among otherplaces, in transport T and exchange
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* EXCHANGE.
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*/
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void
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cookie_gen(struct transport *t, struct exchange *exchange, u_int8_t *buf,
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size_t len)
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{
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struct hash *hash = hash_get(HASH_SHA1);
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u_int8_t tmpsecret[COOKIE_SECRET_SIZE];
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struct sockaddr *name;
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hash->Init(hash->ctx);
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(*t->vtbl->get_dst)(t, &name);
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hash->Update(hash->ctx, (u_int8_t *)name, SA_LEN(name));
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(*t->vtbl->get_src)(t, &name);
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hash->Update(hash->ctx, (u_int8_t *)name, SA_LEN(name));
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if (exchange->initiator == 0)
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hash->Update(hash->ctx, exchange->cookies +
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ISAKMP_HDR_ICOOKIE_OFF, ISAKMP_HDR_ICOOKIE_LEN);
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arc4random_buf(tmpsecret, COOKIE_SECRET_SIZE);
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hash->Update(hash->ctx, tmpsecret, COOKIE_SECRET_SIZE);
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hash->Final(hash->digest, hash->ctx);
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memcpy(buf, hash->digest, len);
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}
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