The Tcpdump Group git mirrors - tcpdump/blob - print-esp.c

   1 /*      $NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $        */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that: (1) source code distributions
   9  * retain the above copyright notice and this paragraph in its entirety, (2)
  10  * distributions including binary code include the above copyright notice and
  11  * this paragraph in its entirety in the documentation or other materials
  12  * provided with the distribution, and (3) all advertising materials mentioning
  13  * features or use of this software display the following acknowledgement:
  14  * ``This product includes software developed by the University of California,
  15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  16  * the University nor the names of its contributors may be used to endorse
  17  * or promote products derived from this software without specific prior
  18  * written permission.
  19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  22  */
  23
  24 #ifndef lint
  25 static const char rcsid[] =
  26     "@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.6 2000-01-15 02:33:06 mcr Exp $ (LBL)";
  27 #endif
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <string.h>
  34 #include <sys/param.h>
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #include <sys/socket.h>
  38
  39 #include <net/route.h>
  40 #include <net/if.h>
  41
  42 #include <netinet/in.h>
  43 #include <netinet/if_ether.h>
  44 #include <netinet/in_systm.h>
  45 #include <netinet/ip.h>
  46 #include <netinet/ip_icmp.h>
  47 #include <netinet/ip_var.h>
  48 #include <netinet/udp.h>
  49 #include <netinet/udp_var.h>
  50 #include <netinet/tcp.h>
  51
  52 #ifdef HAVE_LIBCRYPTO
  53 #include <des.h>
  54 #include <blowfish.h>
  55 #ifdef HAVE_RC5_H
  56 #include <rc5.h>
  57 #endif
  58 #ifdef HAVE_CAST_H
  59 #include <cast.h>
  60 #endif
  61 #endif
  62
  63 #include <stdio.h>
  64
  65 #ifdef INET6
  66 #include <netinet/ip6.h>
  67 #endif
  68
  69 /* there's no standard definition so we are on our own */
  70 struct esp {
  71         u_int32_t       esp_spi;        /* ESP */
  72         /*variable size, 32bit bound*/  /* Initialization Vector */
  73         /*variable size*/               /* Payload data */
  74         /*variable size*/               /* padding */
  75         /*8bit*/                        /* pad size */
  76         /*8bit*/                        /* next header */
  77         /*8bit*/                        /* next header */
  78         /*variable size, 32bit bound*/  /* Authentication data (new IPsec) */
  79 };
  80
  81 struct newesp {
  82         u_int32_t       esp_spi;        /* ESP */
  83         u_int32_t       esp_seq;        /* Sequence number */
  84         /*variable size*/               /* (IV and) Payload data */
  85         /*variable size*/               /* padding */
  86         /*8bit*/                        /* pad size */
  87         /*8bit*/                        /* next header */
  88         /*8bit*/                        /* next header */
  89         /*variable size, 32bit bound*/  /* Authentication data */
  90 };
  91
  92 #include "interface.h"
  93 #include "addrtoname.h"
  94
  95 int
  96 esp_print(register const u_char *bp, register const u_char *bp2, int *nhdr)
  97 {
  98         register const struct esp *esp;
  99         register const u_char *ep;
 100         u_int32_t spi;
 101         enum { NONE, DESCBC, BLOWFISH, RC5, CAST128, DES3CBC } algo = NONE;
 102         struct ip *ip = NULL;
 103 #ifdef INET6
 104         struct ip6_hdr *ip6 = NULL;
 105 #endif
 106         int advance;
 107         int len;
 108         char *secret = NULL;
 109         int ivlen = 0;
 110         u_char *ivoff;
 111
 112         esp = (struct esp *)bp;
 113         spi = (u_int32_t)ntohl(esp->esp_spi);
 114
 115         /* 'ep' points to the end of avaible data. */
 116         ep = snapend;
 117
 118         if ((u_char *)(esp + 1) >= ep - sizeof(struct esp)) {
 119                 fputs("[|ESP]", stdout);
 120                 goto fail;
 121         }
 122         printf("ESP(spi=%u", spi);
 123         printf(",seq=0x%x", (u_int32_t)ntohl(*(u_int32_t *)(esp + 1)));
 124         printf(")");
 125
 126         /* if we don't have decryption key, we can't decrypt this packet. */
 127         if (!espsecret)
 128                 goto fail;
 129
 130         if (strncmp(espsecret, "des-cbc:", 8) == 0
 131          && strlen(espsecret + 8) == 8) {
 132                 algo = DESCBC;
 133                 ivlen = 8;
 134                 secret = espsecret + 8;
 135         } else if (strncmp(espsecret, "blowfish-cbc:", 13) == 0) {
 136                 algo = BLOWFISH;
 137                 ivlen = 8;
 138                 secret = espsecret + 13;
 139         } else if (strncmp(espsecret, "rc5-cbc:", 8) == 0) {
 140                 algo = RC5;
 141                 ivlen = 8;
 142                 secret = espsecret + 8;
 143         } else if (strncmp(espsecret, "cast128-cbc:", 12) == 0) {
 144                 algo = CAST128;
 145                 ivlen = 8;
 146                 secret = espsecret + 12;
 147         } else if (strncmp(espsecret, "3des-cbc:", 9) == 0
 148                 && strlen(espsecret + 9) == 24) {
 149                 algo = DES3CBC;
 150                 ivlen = 8;
 151                 secret = espsecret + 9;
 152         } else if (strncmp(espsecret, "none:", 5) == 0) {
 153                 algo = NONE;
 154                 ivlen = 0;
 155                 secret = espsecret + 5;
 156         } else if (strlen(espsecret) == 8) {
 157                 algo = DESCBC;
 158                 ivlen = 8;
 159                 secret = espsecret;
 160         } else {
 161                 algo = NONE;
 162                 ivlen = 0;
 163                 secret = espsecret;
 164         }
 165
 166         ip = (struct ip *)bp2;
 167         switch (ip->ip_v) {
 168 #ifdef INET6
 169         case 6:
 170                 ip6 = (struct ip6_hdr *)bp2;
 171                 ip = NULL;
 172                 /* we do not attempt to decrypt jumbograms */
 173                 if (!ntohs(ip6->ip6_plen))
 174                         goto fail;
 175                 /* if we can't get nexthdr, we do not need to decrypt it */
 176                 len = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 177                 break;
 178 #endif /*INET6*/
 179         case 4:
 180 #ifdef INET6
 181                 ip6 = NULL;
 182 #endif
 183                 len = ntohs(ip->ip_len);
 184                 break;
 185         default:
 186                 goto fail;
 187         }
 188
 189         /* if we can't get nexthdr, we do not need to decrypt it */
 190         if (ep - bp2 < len)
 191                 goto fail;
 192
 193         if (Rflag)
 194                 ivoff = (u_char *)(esp + 1) + sizeof(u_int32_t);
 195         else
 196                 ivoff = (u_char *)(esp + 1);
 197
 198         switch (algo) {
 199         case DESCBC:
 200 #ifdef HAVE_LIBCRYPTO
 201             {
 202                 u_char iv[8];
 203                 des_key_schedule schedule;
 204                 u_char *p;
 205
 206                 switch (ivlen) {
 207                 case 4:
 208                         memcpy(iv, ivoff, 4);
 209                         memcpy(&iv[4], ivoff, 4);
 210                         p = &iv[4];
 211                         *p++ ^= 0xff;
 212                         *p++ ^= 0xff;
 213                         *p++ ^= 0xff;
 214                         *p++ ^= 0xff;
 215                         break;
 216                 case 8:
 217                         memcpy(iv, ivoff, 8);
 218                         break;
 219                 default:
 220                         goto fail;
 221                 }
 222
 223                 des_check_key = 0;
 224                 des_set_key((void *)secret, schedule);
 225
 226                 p = ivoff + ivlen;
 227                 des_cbc_encrypt((void *)p, (void *)p,
 228                         (long)(ep - p), schedule, (void *)iv,
 229                         DES_DECRYPT);
 230                 advance = ivoff - (u_char *)esp + ivlen;
 231                 break;
 232             }
 233 #else
 234                 goto fail;
 235 #endif /*HAVE_LIBCRYPTO*/
 236
 237         case BLOWFISH:
 238 #ifdef HAVE_LIBCRYPTO
 239             {
 240                 BF_KEY schedule;
 241                 u_char *p;
 242
 243                 BF_set_key(&schedule, strlen(secret), secret);
 244
 245                 p = ivoff + ivlen;
 246                 BF_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 247                         BF_DECRYPT);
 248                 advance = ivoff - (u_char *)esp + ivlen;
 249                 break;
 250             }
 251 #else
 252                 goto fail;
 253 #endif /*HAVE_LIBCRYPTO*/
 254
 255         case RC5:
 256 #if defined(HAVE_LIBCRYPTO) && defined(HAVE_RC5_H)
 257             {
 258                 RC5_32_KEY schedule;
 259                 u_char *p;
 260
 261                 RC5_32_set_key(&schedule, strlen(secret), secret,
 262                         RC5_16_ROUNDS);
 263
 264                 p = ivoff + ivlen;
 265                 RC5_32_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 266                         RC5_DECRYPT);
 267                 advance = ivoff - (u_char *)esp + ivlen;
 268                 break;
 269             }
 270 #else
 271                 goto fail;
 272 #endif /*HAVE_LIBCRYPTO*/
 273
 274         case CAST128:
 275 #if defined(HAVE_LIBCRYPTO) && defined(HAVE_CAST_H) && !defined(HAVE_BUGGY_CAST128)
 276             {
 277                 CAST_KEY schedule;
 278                 u_char *p;
 279
 280                 CAST_set_key(&schedule, strlen(secret), secret);
 281
 282                 p = ivoff + ivlen;
 283                 CAST_cbc_encrypt(p, p, (long)(ep - p), &schedule, ivoff,
 284                         CAST_DECRYPT);
 285                 advance = ivoff - (u_char *)esp + ivlen;
 286                 break;
 287             }
 288 #else
 289                 goto fail;
 290 #endif /*HAVE_LIBCRYPTO*/
 291
 292         case DES3CBC:
 293 #if defined(HAVE_LIBCRYPTO)
 294             {
 295                 des_key_schedule s1, s2, s3;
 296                 u_char *p;
 297
 298                 des_check_key = 0;
 299                 des_set_key((void *)secret, s1);
 300                 des_set_key((void *)(secret + 8), s2);
 301                 des_set_key((void *)(secret + 16), s3);
 302
 303                 p = ivoff + ivlen;
 304                 des_ede3_cbc_encrypt((void *)p, (void *)p,
 305                         (long)(ep - p), s1, s2, s3, (void *)ivoff, DES_DECRYPT);
 306                 advance = ivoff - (u_char *)esp + ivlen;
 307                 break;
 308             }
 309 #else
 310                 goto fail;
 311 #endif /*HAVE_LIBCRYPTO*/
 312
 313         case NONE:
 314         default:
 315                 if (Rflag)
 316                         advance = sizeof(struct esp) + sizeof(u_int32_t);
 317                 else
 318                         advance = sizeof(struct esp);
 319                 break;
 320         }
 321
 322         /* sanity check for pad length */
 323         if (ep - bp < *(ep - 2))
 324                 goto fail;
 325
 326         if (nhdr)
 327                 *nhdr = *(ep - 1);
 328
 329         printf(": ");
 330         return advance;
 331
 332 fail:
 333         if (nhdr)
 334                 *nhdr = -1;
 335         return 65536;
 336 }