410 lines
8.8 KiB
C
410 lines
8.8 KiB
C
/* $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $ */
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/*
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* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
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* The Regents of the University of California. 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: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static const char rcsid[] =
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"@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.20 2002/01/21 11:39:59 mcr Exp $ (LBL)";
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#endif
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <string.h>
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#include <sys/param.h>
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#include <sys/time.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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#ifdef HAVE_LIBCRYPTO
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#include <openssl/des.h>
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#include <openssl/blowfish.h>
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#ifdef HAVE_RC5_H
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#include <openssl/rc5.h>
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#endif
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#ifdef HAVE_CAST_H
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#include <openssl/cast.h>
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#endif
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#endif
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#include <stdio.h>
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#include "ip.h"
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#include "esp.h"
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#ifdef INET6
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#include "ip6.h"
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#endif
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#define AVOID_CHURN 1
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#include "interface.h"
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#include "addrtoname.h"
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static struct esp_algorithm *espsecret_xform=NULL; /* cache of decoded alg. */
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static char *espsecret_key=NULL;
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enum cipher { NONE,
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DESCBC,
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BLOWFISH,
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RC5,
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CAST128,
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DES3CBC};
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struct esp_algorithm {
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char *name;
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enum cipher algo;
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int ivlen;
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int authlen;
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int replaysize;
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};
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struct esp_algorithm esp_xforms[]={
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{"none", NONE, 0, 0, 0},
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{"des-cbc", DESCBC, 8, 0, 0},
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{"des-cbc-hmac96", DESCBC, 8, 12, 4},
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{"blowfish-cbc", BLOWFISH,8, 0, 0},
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{"blowfish-cbc-hmac96", BLOWFISH,8, 12, 4},
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{"rc5-cbc", RC5, 8, 0, 0},
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{"rc5-cbc-hmac96", RC5, 8, 12, 4},
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{"cast128-cbc", CAST128, 8, 0, 0},
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{"cast128-cbc-hmac96", CAST128, 8, 12, 4},
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{"3des-cbc-hmac96", DES3CBC, 8, 12, 4},
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};
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static int hexdigit(char hex)
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{
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if(hex >= '0' && hex <= '9') {
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return (hex - '0');
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} else if(hex >= 'A' && hex <= 'F') {
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return (hex - 'A' + 10);
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} else if(hex >= 'a' && hex <= 'f') {
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return (hex - 'a' + 10);
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} else {
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printf("invalid hex digit %c in espsecret\n", hex);
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return 0;
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}
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}
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static int hex2byte(char *hexstring)
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{
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int byte;
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byte = (hexdigit(hexstring[0]) << 4) +
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hexdigit(hexstring[1]);
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return byte;
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}
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void esp_print_decodesecret()
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{
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char *colon;
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int len, i;
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struct esp_algorithm *xf;
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if(espsecret == NULL) {
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/* set to NONE transform */
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espsecret_xform = esp_xforms;
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return;
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}
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if(espsecret_key != NULL) {
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return;
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}
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colon = strchr(espsecret, ':');
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if(colon == NULL) {
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printf("failed to decode espsecret: %s\n",
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espsecret);
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/* set to NONE transform */
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espsecret_xform = esp_xforms;
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}
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len = colon - espsecret;
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xf = esp_xforms;
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while(xf->name && strncasecmp(espsecret, xf->name, len)!=0) {
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xf++;
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}
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if(xf->name == NULL) {
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printf("failed to find cipher algo %s\n",
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espsecret);
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espsecret_xform = esp_xforms;
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return;
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}
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espsecret_xform = xf;
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colon++;
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if(colon[0]=='0' && colon[1]=='x') {
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/* decode some hex! */
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colon+=2;
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len = strlen(colon) / 2;
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espsecret_key = (char *)malloc(len);
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if(espsecret_key == NULL) {
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fprintf(stderr, "%s: ran out of memory (%d) to allocate secret key\n",
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program_name, len);
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exit(2);
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}
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i = 0;
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while(colon[0] != '\0' && colon[1]!='\0') {
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espsecret_key[i]=hex2byte(colon);
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colon+=2;
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i++;
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}
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} else {
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espsecret_key = colon;
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}
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}
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int
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esp_print(register const u_char *bp, register const u_char *bp2,
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int *nhdr, int *padlen)
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{
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register const struct esp *esp;
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register const u_char *ep;
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u_int32_t spi;
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struct ip *ip = NULL;
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#ifdef INET6
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struct ip6_hdr *ip6 = NULL;
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#endif
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int advance;
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int len;
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char *secret;
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int ivlen = 0;
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u_char *ivoff;
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u_char *p;
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esp = (struct esp *)bp;
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spi = (u_int32_t)ntohl(esp->esp_spi);
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secret = NULL;
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#if 0
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/* keep secret out of a register */
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p = (u_char *)&secret;
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#endif
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/* 'ep' points to the end of available data. */
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ep = snapend;
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if ((u_char *)(esp + 1) >= ep - sizeof(struct esp)) {
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fputs("[|ESP]", stdout);
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goto fail;
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}
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printf("ESP(spi=0x%08x", spi);
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printf(",seq=0x%x", (u_int32_t)ntohl(*(u_int32_t *)(esp + 1)));
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printf(")");
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/* if we don't have decryption key, we can't decrypt this packet. */
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if (!espsecret)
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goto fail;
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if(!espsecret_xform) {
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esp_print_decodesecret();
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}
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if(espsecret_xform->algo == NONE) {
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goto fail;
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}
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ip = (struct ip *)bp2;
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switch (IP_V(ip)) {
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#ifdef INET6
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case 6:
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ip6 = (struct ip6_hdr *)bp2;
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ip = NULL;
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/* we do not attempt to decrypt jumbograms */
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if (!ntohs(ip6->ip6_plen))
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goto fail;
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/* if we can't get nexthdr, we do not need to decrypt it */
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len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
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break;
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#endif /*INET6*/
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case 4:
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/* nexthdr & padding are in the last fragment */
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if (ntohs(ip->ip_off) & IP_MF)
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goto fail;
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#ifdef INET6
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ip6 = NULL;
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#endif
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len = ntohs(ip->ip_len);
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break;
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default:
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goto fail;
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}
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/* if we can't get nexthdr, we do not need to decrypt it */
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if (ep - bp2 < len)
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goto fail;
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ivoff = (u_char *)(esp + 1) + espsecret_xform->replaysize;
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ivlen = espsecret_xform->ivlen;
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secret = espsecret_key;
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switch (espsecret_xform->algo) {
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case DESCBC:
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#ifdef HAVE_LIBCRYPTO
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{
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u_char iv[8];
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des_key_schedule schedule;
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switch (ivlen) {
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case 4:
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memcpy(iv, ivoff, 4);
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memcpy(&iv[4], ivoff, 4);
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p = &iv[4];
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*p++ ^= 0xff;
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*p++ ^= 0xff;
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*p++ ^= 0xff;
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*p++ ^= 0xff;
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break;
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case 8:
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memcpy(iv, ivoff, 8);
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break;
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default:
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goto fail;
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}
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des_check_key = 0;
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des_set_key((void *)secret, schedule);
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p = ivoff + ivlen;
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des_cbc_encrypt((void *)p, (void *)p,
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(long)(ep - p), schedule, (void *)iv,
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DES_DECRYPT);
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advance = ivoff - (u_char *)esp + ivlen;
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break;
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}
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#else
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goto fail;
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#endif /*HAVE_LIBCRYPTO*/
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case BLOWFISH:
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#ifdef HAVE_LIBCRYPTO
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{
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BF_KEY schedule;
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BF_set_key(&schedule, strlen(secret), secret);
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p = ivoff + ivlen;
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BF_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
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BF_DECRYPT);
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advance = ivoff - (u_char *)esp + ivlen;
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break;
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}
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#else
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goto fail;
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#endif /*HAVE_LIBCRYPTO*/
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case RC5:
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#if defined(HAVE_LIBCRYPTO) && defined(HAVE_RC5_H)
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{
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RC5_32_KEY schedule;
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RC5_32_set_key(&schedule, strlen(secret), secret,
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RC5_16_ROUNDS);
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p = ivoff + ivlen;
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RC5_32_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
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RC5_DECRYPT);
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advance = ivoff - (u_char *)esp + ivlen;
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break;
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}
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#else
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goto fail;
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#endif /*HAVE_LIBCRYPTO*/
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case CAST128:
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#if defined(HAVE_LIBCRYPTO) && defined(HAVE_CAST_H) && !defined(HAVE_BUGGY_CAST128)
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{
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CAST_KEY schedule;
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CAST_set_key(&schedule, strlen(secret), secret);
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p = ivoff + ivlen;
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CAST_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
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CAST_DECRYPT);
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advance = ivoff - (u_char *)esp + ivlen;
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break;
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}
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#else
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goto fail;
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#endif /*HAVE_LIBCRYPTO*/
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case DES3CBC:
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#if defined(HAVE_LIBCRYPTO)
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{
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des_key_schedule s1, s2, s3;
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des_check_key = 1;
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des_set_odd_parity((void *)secret);
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des_set_odd_parity((void *)secret+8);
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des_set_odd_parity((void *)secret+16);
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if(des_set_key((void *)secret, s1) != 0) {
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printf("failed to schedule key 1\n");
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}
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if(des_set_key((void *)(secret + 8), s2)!=0) {
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printf("failed to schedule key 2\n");
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}
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if(des_set_key((void *)(secret + 16), s3)!=0) {
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printf("failed to schedule key 3\n");
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}
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p = ivoff + ivlen;
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des_ede3_cbc_encrypt((void *)p, (void *)p,
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(long)(ep - p),
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s1, s2, s3,
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(void *)ivoff, DES_DECRYPT);
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advance = ivoff - (u_char *)esp + ivlen;
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break;
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}
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#else
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goto fail;
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#endif /*HAVE_LIBCRYPTO*/
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case NONE:
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default:
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advance = sizeof(struct esp) + espsecret_xform->replaysize;
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break;
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}
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ep = ep - espsecret_xform->authlen;
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/* sanity check for pad length */
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if (ep - bp < *(ep - 2))
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goto fail;
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if (padlen)
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*padlen = *(ep - 2) + 2;
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if (nhdr)
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*nhdr = *(ep - 1);
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printf(": ");
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return advance;
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fail:
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if (nhdr)
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*nhdr = -1;
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return 65536;
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}
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