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NetBSD/dist/tcpdump/print-esp.c

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/* $NetBSD: print-esp.c,v 1.6 2004/09/27 23:04:24 dyoung Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static const char rcsid[] _U_ =
"@(#) Header: /tcpdump/master/tcpdump/print-esp.c,v 1.44.2.4 2003/11/19 05:36:40 guy Exp (LBL)";
#else
__RCSID("$NetBSD: print-esp.c,v 1.6 2004/09/27 23:04:24 dyoung Exp $");
#endif
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <tcpdump-stdinc.h>
#include <stdlib.h>
#ifdef HAVE_LIBCRYPTO
#ifdef HAVE_OPENSSL_EVP_H
#include <openssl/evp.h>
#endif
#endif
#include <stdio.h>
#include "ip.h"
#include "esp.h"
#ifdef INET6
#include "ip6.h"
#endif
#if defined(__MINGW32__) || defined(__WATCOMC__)
extern char *strsep(char **stringp, const char *delim); /* Missing/strsep.c */
#endif
#include "interface.h"
#include "addrtoname.h"
#include "extract.h"
#ifndef HAVE_SOCKADDR_STORAGE
#ifdef INET6
struct sockaddr_storage {
union {
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} un;
};
#else
#define sockaddr_storage sockaddr
#endif
#endif /* HAVE_SOCKADDR_STORAGE */
#ifdef HAVE_LIBCRYPTO
struct sa_list {
struct sa_list *next;
struct sockaddr_storage daddr;
u_int32_t spi;
const EVP_CIPHER *evp;
int ivlen;
int authlen;
char secret[256]; /* is that big enough for all secrets? */
int secretlen;
};
static struct sa_list *sa_list_head = NULL;
static struct sa_list *sa_default = NULL;
static void esp_print_addsa(struct sa_list *sa, int sa_def)
{
/* copy the "sa" */
struct sa_list *nsa;
nsa = (struct sa_list *)malloc(sizeof(struct sa_list));
if (nsa == NULL)
error("ran out of memory to allocate sa structure");
*nsa = *sa;
if (sa_def)
sa_default = nsa;
nsa->next = sa_list_head;
sa_list_head = nsa;
}
static int hexdigit(char hex)
{
if (hex >= '0' && hex <= '9')
return (hex - '0');
else if (hex >= 'A' && hex <= 'F')
return (hex - 'A' + 10);
else if (hex >= 'a' && hex <= 'f')
return (hex - 'a' + 10);
else {
printf("invalid hex digit %c in espsecret\n", hex);
return 0;
}
}
static int hex2byte(char *hexstring)
{
int byte;
byte = (hexdigit(hexstring[0]) << 4) + hexdigit(hexstring[1]);
return byte;
}
/*
* decode the form: SPINUM@IP <tab> ALGONAME:0xsecret
*
* special form: file /name
* causes us to go read from this file instead.
*
*/
static void esp_print_decode_onesecret(char *line)
{
struct sa_list sa1;
int sa_def;
char *spikey;
char *decode;
spikey = strsep(&line, " \t");
sa_def = 0;
memset(&sa1, 0, sizeof(struct sa_list));
/* if there is only one token, then it is an algo:key token */
if (line == NULL) {
decode = spikey;
spikey = NULL;
/* memset(&sa1.daddr, 0, sizeof(sa1.daddr)); */
/* sa1.spi = 0; */
sa_def = 1;
} else
decode = line;
if (spikey && strcasecmp(spikey, "file") == 0) {
/* open file and read it */
FILE *secretfile;
char fileline[1024];
char *nl;
secretfile = fopen(line, FOPEN_READ_TXT);
if (secretfile == NULL) {
perror(line);
exit(3);
}
while (fgets(fileline, sizeof(fileline)-1, secretfile) != NULL) {
/* remove newline from the line */
nl = strchr(fileline, '\n');
if (nl)
*nl = '\0';
if (fileline[0] == '#') continue;
if (fileline[0] == '\0') continue;
esp_print_decode_onesecret(fileline);
}
fclose(secretfile);
return;
}
if (spikey) {
char *spistr, *foo;
u_int32_t spino;
struct sockaddr_in *sin;
#ifdef INET6
struct sockaddr_in6 *sin6;
#endif
spistr = strsep(&spikey, "@");
spino = strtoul(spistr, &foo, 0);
if (spistr == foo || !spikey) {
printf("print_esp: failed to decode spi# %s\n", foo);
return;
}
sa1.spi = spino;
sin = (struct sockaddr_in *)&sa1.daddr;
#ifdef INET6
sin6 = (struct sockaddr_in6 *)&sa1.daddr;
if (inet_pton(AF_INET6, spikey, &sin6->sin6_addr) == 1) {
#ifdef HAVE_SOCKADDR_SA_LEN
sin6->sin6_len = sizeof(struct sockaddr_in6);
#endif
sin6->sin6_family = AF_INET6;
} else
#endif
if (inet_pton(AF_INET, spikey, &sin->sin_addr) == 1) {
#ifdef HAVE_SOCKADDR_SA_LEN
sin->sin_len = sizeof(struct sockaddr_in);
#endif
sin->sin_family = AF_INET;
} else {
printf("print_esp: can not decode IP# %s\n", spikey);
return;
}
}
if (decode) {
char *colon, *p;
char espsecret_key[256];
int len;
size_t i;
const EVP_CIPHER *evp;
int ivlen = 8;
int authlen = 0;
/* skip any blank spaces */
while (isspace((unsigned char)*decode))
decode++;
colon = strchr(decode, ':');
if (colon == NULL) {
printf("failed to decode espsecret: %s\n", decode);
return;
}
*colon = '\0';
len = colon - decode;
if (strlen(decode) > strlen("-hmac96") &&
!strcmp(decode + strlen(decode) - strlen("-hmac96"),
"-hmac96")) {
p = strstr(decode, "-hmac96");
*p = '\0';
authlen = 12;
}
if (strlen(decode) > strlen("-cbc") &&
!strcmp(decode + strlen(decode) - strlen("-cbc"), "-cbc")) {
p = strstr(decode, "-cbc");
*p = '\0';
}
evp = EVP_get_cipherbyname(decode);
if (!evp) {
printf("failed to find cipher algo %s\n", decode);
sa1.evp = NULL;
sa1.authlen = 0;
sa1.ivlen = 0;
return;
}
sa1.evp = evp;
sa1.authlen = authlen;
sa1.ivlen = ivlen;
colon++;
if (colon[0] == '0' && colon[1] == 'x') {
/* decode some hex! */
colon += 2;
len = strlen(colon) / 2;
if (len > 256) {
printf("secret is too big: %d\n", len);
return;
}
i = 0;
while (colon[0] != '\0' && colon[1]!='\0') {
espsecret_key[i] = hex2byte(colon);
colon += 2;
i++;
}
memcpy(sa1.secret, espsecret_key, i);
sa1.secretlen = i;
} else {
i = strlen(colon);
if (i < sizeof(sa1.secret)) {
memcpy(sa1.secret, colon, i);
sa1.secretlen = i;
} else {
memcpy(sa1.secret, colon, sizeof(sa1.secret));
sa1.secretlen = sizeof(sa1.secret);
}
}
}
esp_print_addsa(&sa1, sa_def);
}
static void esp_print_decodesecret(void)
{
char *line;
char *p;
p = espsecret;
while (espsecret && espsecret[0] != '\0') {
/* pick out the first line or first thing until a comma */
if ((line = strsep(&espsecret, "\n,")) == NULL) {
line = espsecret;
espsecret = NULL;
}
esp_print_decode_onesecret(line);
}
}
static void esp_init(void)
{
OpenSSL_add_all_algorithms();
EVP_add_cipher_alias(SN_des_ede3_cbc, "3des");
}
#endif
int
esp_print(const u_char *bp, const u_char *bp2
#ifndef HAVE_LIBCRYPTO
_U_
#endif
,
int *nhdr
#ifndef HAVE_LIBCRYPTO
_U_
#endif
,
int *padlen
#ifndef HAVE_LIBCRYPTO
_U_
#endif
)
{
register const struct newesp *esp;
register const u_char *ep;
#ifdef HAVE_LIBCRYPTO
struct ip *ip;
struct sa_list *sa = NULL;
int espsecret_keylen;
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
#endif
int advance;
int len;
char *secret;
int ivlen = 0;
u_char *ivoff;
const u_char *p;
EVP_CIPHER_CTX ctx;
int blocksz;
static int initialized = 0;
#endif
esp = (struct newesp *)bp;
#ifdef HAVE_LIBCRYPTO
secret = NULL;
advance = 0;
if (!initialized) {
esp_init();
initialized = 1;
}
#endif
#if 0
/* keep secret out of a register */
p = (u_char *)&secret;
#endif
/* 'ep' points to the end of available data. */
ep = snapend;
if ((u_char *)(esp + 1) >= ep) {
fputs("[|ESP]", stdout);
goto fail;
}
printf("ESP(spi=0x%08x", EXTRACT_32BITS(&esp->esp_spi));
printf(",seq=0x%x", EXTRACT_32BITS(&esp->esp_seq));
printf(")");
#ifndef HAVE_LIBCRYPTO
goto fail;
#else
/* initiailize SAs */
if (sa_list_head == NULL) {
if (!espsecret)
goto fail;
esp_print_decodesecret();
}
if (sa_list_head == NULL)
goto fail;
ip = (struct ip *)bp2;
switch (IP_V(ip)) {
#ifdef INET6
case 6:
ip6 = (struct ip6_hdr *)bp2;
/* we do not attempt to decrypt jumbograms */
if (!EXTRACT_16BITS(&ip6->ip6_plen))
goto fail;
/* if we can't get nexthdr, we do not need to decrypt it */
len = sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen);
/* see if we can find the SA, and if so, decode it */
for (sa = sa_list_head; sa != NULL; sa = sa->next) {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&sa->daddr;
if (sa->spi == ntohl(esp->esp_spi) &&
sin6->sin6_family == AF_INET6 &&
memcmp(&sin6->sin6_addr, &ip6->ip6_dst,
sizeof(struct in6_addr)) == 0) {
break;
}
}
break;
#endif /*INET6*/
case 4:
/* nexthdr & padding are in the last fragment */
if (EXTRACT_16BITS(&ip->ip_off) & IP_MF)
goto fail;
len = EXTRACT_16BITS(&ip->ip_len);
/* see if we can find the SA, and if so, decode it */
for (sa = sa_list_head; sa != NULL; sa = sa->next) {
struct sockaddr_in *sin = (struct sockaddr_in *)&sa->daddr;
if (sa->spi == ntohl(esp->esp_spi) &&
sin->sin_family == AF_INET &&
sin->sin_addr.s_addr == ip->ip_dst.s_addr) {
break;
}
}
break;
default:
goto fail;
}
/* if we didn't find the specific one, then look for
* an unspecified one.
*/
if (sa == NULL)
sa = sa_default;
/* if not found fail */
if (sa == NULL)
goto fail;
/* if we can't get nexthdr, we do not need to decrypt it */
if (ep - bp2 < len)
goto fail;
if (ep - bp2 > len) {
/* FCS included at end of frame (NetBSD 1.6 or later) */
ep = bp2 + len;
}
ivoff = (u_char *)(esp + 1) + 0;
ivlen = sa->ivlen;
secret = sa->secret;
espsecret_keylen = sa->secretlen;
if (sa->evp) {
memset(&ctx, 0, sizeof(ctx));
if (EVP_CipherInit(&ctx, sa->evp, secret, NULL, 0) < 0)
printf("espkey init failed");
blocksz = EVP_CIPHER_CTX_block_size(&ctx);
p = ivoff;
EVP_CipherInit(&ctx, NULL, NULL, p, 0);
EVP_Cipher(&ctx, (void *)(p + ivlen), p + ivlen,
ep - (p + ivlen));
advance = ivoff - (u_char *)esp + ivlen;
} else
advance = sizeof(struct newesp);
ep = ep - sa->authlen;
/* sanity check for pad length */
if (ep - bp < *(ep - 2))
goto fail;
if (padlen)
*padlen = *(ep - 2) + 2;
if (nhdr)
*nhdr = *(ep - 1);
printf(": ");
return advance;
#endif
fail:
return -1;
}
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