512 lines
11 KiB
C
512 lines
11 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[] _U_ =
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"@(#) $Header: /tcpdump/master/tcpdump/print-esp.c,v 1.55.2.1 2005/04/21 06:44:57 guy 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 <tcpdump-stdinc.h>
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#include <stdlib.h>
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#ifdef HAVE_LIBCRYPTO
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#ifdef HAVE_OPENSSL_EVP_H
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#include <openssl/evp.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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#include "netdissect.h"
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#include "addrtoname.h"
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#include "extract.h"
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#ifndef HAVE_SOCKADDR_STORAGE
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#ifdef INET6
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struct sockaddr_storage {
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union {
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struct sockaddr_in sin;
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struct sockaddr_in6 sin6;
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} un;
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};
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#else
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#define sockaddr_storage sockaddr
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#endif
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#endif /* HAVE_SOCKADDR_STORAGE */
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#ifdef HAVE_LIBCRYPTO
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struct sa_list {
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struct sa_list *next;
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struct sockaddr_storage daddr;
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u_int32_t spi;
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const EVP_CIPHER *evp;
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int ivlen;
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int authlen;
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u_char secret[256]; /* is that big enough for all secrets? */
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int secretlen;
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};
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static void esp_print_addsa(netdissect_options *ndo,
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struct sa_list *sa, int sa_def)
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{
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/* copy the "sa" */
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struct sa_list *nsa;
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nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
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if (nsa == NULL)
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(*ndo->ndo_error)(ndo, "ran out of memory to allocate sa structure");
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*nsa = *sa;
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if (sa_def)
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ndo->ndo_sa_default = nsa;
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nsa->next = ndo->ndo_sa_list_head;
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ndo->ndo_sa_list_head = nsa;
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}
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static u_int hexdigit(netdissect_options *ndo, 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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(*ndo->ndo_error)(ndo, "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 u_int hex2byte(netdissect_options *ndo, char *hexstring)
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{
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u_int byte;
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byte = (hexdigit(ndo, hexstring[0]) << 4) + hexdigit(ndo, hexstring[1]);
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return byte;
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}
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/*
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* decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
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*
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* special form: file /name
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* causes us to go read from this file instead.
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*
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*/
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static void esp_print_decode_onesecret(netdissect_options *ndo, char *line)
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{
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struct sa_list sa1;
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int sa_def;
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char *spikey;
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char *decode;
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spikey = strsep(&line, " \t");
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sa_def = 0;
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memset(&sa1, 0, sizeof(struct sa_list));
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/* if there is only one token, then it is an algo:key token */
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if (line == NULL) {
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decode = spikey;
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spikey = NULL;
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/* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
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/* sa1.spi = 0; */
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sa_def = 1;
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} else
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decode = line;
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if (spikey && strcasecmp(spikey, "file") == 0) {
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/* open file and read it */
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FILE *secretfile;
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char fileline[1024];
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char *nl;
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secretfile = fopen(line, FOPEN_READ_TXT);
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if (secretfile == NULL) {
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perror(line);
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exit(3);
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}
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while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
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/* remove newline from the line */
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nl = strchr(fileline, '\n');
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if (nl)
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*nl = '\0';
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if (fileline[0] == '#') continue;
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if (fileline[0] == '\0') continue;
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esp_print_decode_onesecret(ndo, fileline);
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}
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fclose(secretfile);
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return;
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}
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if (spikey) {
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char *spistr, *foo;
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u_int32_t spino;
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struct sockaddr_in *sin;
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#ifdef INET6
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struct sockaddr_in6 *sin6;
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#endif
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spistr = strsep(&spikey, "@");
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spino = strtoul(spistr, &foo, 0);
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if (spistr == foo || !spikey) {
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(*ndo->ndo_warning)(ndo, "print_esp: failed to decode spi# %s\n", foo);
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return;
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}
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sa1.spi = spino;
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sin = (struct sockaddr_in *)&sa1.daddr;
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#ifdef INET6
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sin6 = (struct sockaddr_in6 *)&sa1.daddr;
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if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) {
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#ifdef HAVE_SOCKADDR_SA_LEN
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sin6->sin6_len = sizeof(struct sockaddr_in6);
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#endif
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sin6->sin6_family = AF_INET6;
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} else
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#endif
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if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) {
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#ifdef HAVE_SOCKADDR_SA_LEN
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sin->sin_len = sizeof(struct sockaddr_in);
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#endif
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sin->sin_family = AF_INET;
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} else {
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(*ndo->ndo_warning)(ndo, "print_esp: can not decode IP# %s\n", spikey);
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return;
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}
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}
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if (decode) {
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char *colon, *p;
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u_char espsecret_key[256];
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int len;
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size_t i;
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const EVP_CIPHER *evp;
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int authlen = 0;
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/* skip any blank spaces */
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while (isspace((unsigned char)*decode))
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decode++;
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colon = strchr(decode, ':');
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if (colon == NULL) {
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(*ndo->ndo_warning)(ndo, "failed to decode espsecret: %s\n", decode);
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return;
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}
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*colon = '\0';
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len = colon - decode;
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if (strlen(decode) > strlen("-hmac96") &&
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!strcmp(decode + strlen(decode) - strlen("-hmac96"),
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"-hmac96")) {
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p = strstr(decode, "-hmac96");
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*p = '\0';
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authlen = 12;
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}
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if (strlen(decode) > strlen("-cbc") &&
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!strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
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p = strstr(decode, "-cbc");
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*p = '\0';
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}
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evp = EVP_get_cipherbyname(decode);
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if (!evp) {
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(*ndo->ndo_warning)(ndo, "failed to find cipher algo %s\n", decode);
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sa1.evp = NULL;
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sa1.authlen = 0;
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sa1.ivlen = 0;
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return;
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}
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sa1.evp = evp;
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sa1.authlen = authlen;
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sa1.ivlen = EVP_CIPHER_iv_length(evp);
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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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if (len > 256) {
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(*ndo->ndo_warning)(ndo, "secret is too big: %d\n", len);
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return;
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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(ndo, colon);
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colon += 2;
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i++;
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}
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memcpy(sa1.secret, espsecret_key, i);
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sa1.secretlen = i;
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} else {
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i = strlen(colon);
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if (i < sizeof(sa1.secret)) {
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memcpy(sa1.secret, colon, i);
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sa1.secretlen = i;
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} else {
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memcpy(sa1.secret, colon, sizeof(sa1.secret));
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sa1.secretlen = sizeof(sa1.secret);
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}
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}
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}
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esp_print_addsa(ndo, &sa1, sa_def);
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}
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static void esp_print_decodesecret(netdissect_options *ndo)
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{
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char *line;
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char *p;
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p = ndo->ndo_espsecret;
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while (ndo->ndo_espsecret && ndo->ndo_espsecret[0] != '\0') {
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/* pick out the first line or first thing until a comma */
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if ((line = strsep(&ndo->ndo_espsecret, "\n,")) == NULL) {
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line = ndo->ndo_espsecret;
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ndo->ndo_espsecret = NULL;
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}
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esp_print_decode_onesecret(ndo, line);
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}
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}
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static void esp_init(netdissect_options *ndo _U_)
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{
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OpenSSL_add_all_algorithms();
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EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
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}
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#endif
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int
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esp_print(netdissect_options *ndo,
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const u_char *bp, const int length, const u_char *bp2
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#ifndef HAVE_LIBCRYPTO
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_U_
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#endif
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,
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int *nhdr
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#ifndef HAVE_LIBCRYPTO
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_U_
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#endif
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,
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int *padlen
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#ifndef HAVE_LIBCRYPTO
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_U_
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#endif
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)
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{
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register const struct newesp *esp;
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register const u_char *ep;
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#ifdef HAVE_LIBCRYPTO
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struct ip *ip;
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struct sa_list *sa = NULL;
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int espsecret_keylen;
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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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u_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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EVP_CIPHER_CTX ctx;
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int blocksz;
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static int initialized = 0;
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#endif
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esp = (struct newesp *)bp;
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#ifdef HAVE_LIBCRYPTO
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secret = NULL;
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advance = 0;
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if (!initialized) {
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esp_init(ndo);
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initialized = 1;
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}
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#endif
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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 = ndo->ndo_snapend;
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if ((u_char *)(esp + 1) >= ep) {
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fputs("[|ESP]", stdout);
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goto fail;
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}
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(*ndo->ndo_printf)(ndo, "ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
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(*ndo->ndo_printf)(ndo, ",seq=0x%x)", EXTRACT_32BITS(&esp->esp_seq));
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(*ndo->ndo_printf)(ndo, ", length %u", length);
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#ifndef HAVE_LIBCRYPTO
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goto fail;
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#else
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/* initiailize SAs */
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if (ndo->ndo_sa_list_head == NULL) {
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if (!ndo->ndo_espsecret)
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goto fail;
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esp_print_decodesecret(ndo);
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}
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if (ndo->ndo_sa_list_head == NULL)
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goto fail;
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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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/* we do not attempt to decrypt jumbograms */
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if (!EXTRACT_16BITS(&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) + EXTRACT_16BITS(&ip6->ip6_plen);
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/* see if we can find the SA, and if so, decode it */
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for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
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struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr;
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if (sa->spi == ntohl(esp->esp_spi) &&
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sin6->sin6_family == AF_INET6 &&
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memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
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sizeof(struct in6_addr)) == 0) {
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break;
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}
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}
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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 (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
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goto fail;
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len = EXTRACT_16BITS(&ip->ip_len);
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/* see if we can find the SA, and if so, decode it */
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for (sa = ndo->ndo_sa_list_head; sa != NULL; sa = sa->next) {
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struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr;
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if (sa->spi == ntohl(esp->esp_spi) &&
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sin->sin_family == AF_INET &&
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sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
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break;
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}
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}
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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 didn't find the specific one, then look for
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* an unspecified one.
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*/
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if (sa == NULL)
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sa = ndo->ndo_sa_default;
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/* if not found fail */
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if (sa == NULL)
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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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if (ep - bp2 < len)
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goto fail;
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if (ep - bp2 > len) {
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/* FCS included at end of frame (NetBSD 1.6 or later) */
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ep = bp2 + len;
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}
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ivoff = (u_char *)(esp + 1) + 0;
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ivlen = sa->ivlen;
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secret = sa->secret;
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espsecret_keylen = sa->secretlen;
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ep = ep - sa->authlen;
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if (sa->evp) {
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memset(&ctx, 0, sizeof(ctx));
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if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
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(*ndo->ndo_warning)(ndo, "espkey init failed");
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blocksz = EVP_CIPHER_CTX_block_size(&ctx);
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p = ivoff;
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EVP_CipherInit(&ctx, NULL, NULL, p, 0);
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EVP_Cipher(&ctx, p + ivlen, p + ivlen, ep - (p + ivlen));
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advance = ivoff - (u_char *)esp + ivlen;
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} else
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advance = sizeof(struct newesp);
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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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(ndo->ndo_printf)(ndo, ": ");
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return advance;
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#endif
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fail:
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return -1;
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}
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/*
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* Local Variables:
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* c-style: whitesmith
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* c-basic-offset: 8
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* End:
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*/
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