1 /* $OpenBSD: cookie.c,v 1.9 2001/06/29 18:52:16 ho Exp $ */ 2 /* $EOM: cookie.c,v 1.21 1999/08/05 15:00:04 niklas Exp $ */ 3 4 /* 5 * Copyright (c) 1998, 1999 Niklas Hallqvist. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Ericsson Radio Systems. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * This code was written under funding by Ericsson Radio Systems. 35 */ 36 37 #include <sys/types.h> 38 #include <sys/socket.h> 39 #include <sha1.h> 40 #include <stdlib.h> 41 #include <string.h> 42 43 #include "sysdep.h" 44 45 #include "cookie.h" 46 #include "exchange.h" 47 #include "hash.h" 48 #include "transport.h" 49 #include "util.h" 50 51 #define COOKIE_SECRET_SIZE 16 52 53 /* 54 * Generate an anti-clogging token (a protection against an attacker forcing 55 * us to keep state for a flood of connection requests) a.k.a. a cookie 56 * at BUF, LEN bytes long. The cookie will be generated by hashing of 57 * information found, among otherplaces, in transport T and exchange 58 * EXCHANGE. 59 */ 60 void 61 cookie_gen (struct transport *t, struct exchange *exchange, u_int8_t *buf, 62 size_t len) 63 { 64 struct hash* hash = hash_get (HASH_SHA1); 65 struct sockaddr *name; 66 u_int8_t tmpsecret[COOKIE_SECRET_SIZE]; 67 68 hash->Init (hash->ctx); 69 (*t->vtbl->get_dst) (t, &name); 70 hash->Update (hash->ctx, (u_int8_t *)name, name->sa_len); 71 (*t->vtbl->get_src) (t, &name); 72 hash->Update (hash->ctx, (u_int8_t *)name, name->sa_len); 73 if (exchange->initiator == 0) 74 hash->Update (hash->ctx, exchange->cookies + ISAKMP_HDR_ICOOKIE_OFF, 75 ISAKMP_HDR_ICOOKIE_LEN); 76 getrandom (tmpsecret, COOKIE_SECRET_SIZE); 77 hash->Update (hash->ctx, tmpsecret, COOKIE_SECRET_SIZE); 78 hash->Final (hash->digest, hash->ctx); 79 memcpy (buf, hash->digest, len); 80 } 81