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/* $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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} |