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/*
* filesnarf.c
*
* Sniff files from NFS traffic.
*
* Copyright (c) 2000 Dug Song <dugsong@monkey.org>
*
* $Id: filesnarf.c,v 1.13 2001/03/15 08:33:03 dugsong Exp $
*/
#include "config.h"
#include <sys/types.h>
#include <rpc/rpc.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <regex.h>
#include <err.h>
#include <libnet.h>
#include <nids.h>
#include <pcap.h>
#include "decode.h"
#include "pcaputil.h"
#include "nfs_prot.h"
#include "rpc.h"
#include "version.h"
struct myreadargs {
char *filename;
u_int offset;
};
struct fh_map {
u_char fh[NFS3_FHSIZE];
char *filename;
};
#define FH_MAP_SIZE 128
struct fh_map fh_maps[FH_MAP_SIZE];
int fh_map_next = 0;
int fh_map_hint = 0;
int Opt_invert = 0;
regex_t *pregex = NULL;
static void
usage(void)
{
fprintf(stderr, "Version: " VERSION "\n"
"Usage: filesnarf [-i interface | -p pcapfile] [[-v] pattern [expression]]\n");
exit(1);
}
/* XXX - for nfs_prot_xdr.c */
bool_t
xdr_u_int64_t(XDR *xdrs, u_int64_t *nump)
{
int i = 1;
u_char *p = (u_char *)nump;
if (*(char *)&i == 1) { /* endian haack. */
if (xdr_u_long(xdrs, (u_long *)(p + 4)))
return (xdr_u_long(xdrs, (u_long *)p));
}
else {
if (xdr_u_long(xdrs, (u_long *)p))
return (xdr_u_long(xdrs, (u_long *)(p + 4)));
}
return (FALSE);
}
bool_t
xdr_int64_t(XDR *xdrs, int64_t *nump)
{
return (xdr_u_int64_t(xdrs, (u_int64_t *)nump));
}
static void
fh_map_init(void)
{
memset(&fh_maps, 0, sizeof(fh_maps));
}
static void
fh_map_add(char *filename, u_char *fh, int len)
{
struct fh_map *fm;
fm = &fh_maps[fh_map_next];
if (++fh_map_next > FH_MAP_SIZE)
fh_map_next = 0;
memcpy(fm->fh, fh, len);
if ((fm->filename = strdup(filename)) == NULL)
err(1, "fh_map_add: malloc");
}
static char *
fh_map_find(u_char *fh, int len)
{
struct fh_map *fm;
int i;
i = fh_map_hint;
do {
fm = &fh_maps[i];
if (memcmp(fm->fh, fh, len) == 0) {
fh_map_hint = i;
return (fm->filename);
}
if (++i > FH_MAP_SIZE)
i = 0;
} while (i != fh_map_hint);
return (NULL);
}
static int
regex_match(char *string)
{
return (pregex == NULL ||
((regexec(pregex, string, 0, NULL, 0) == 0) ^ Opt_invert));
}
static void
nfs_save(struct tuple4 *addr, struct myreadargs *ma, u_char *buf, int len)
{
int fd;
warnx("%s.%d > %s.%d: %s (%d@%d)",
libnet_addr2name4(addr->daddr, LIBNET_DONT_RESOLVE), addr->dest,
libnet_addr2name4(addr->saddr, LIBNET_DONT_RESOLVE), addr->source,
ma->filename, len, ma->offset);
if ((fd = open(ma->filename, O_WRONLY|O_CREAT, 0644)) >= 0) {
if (lseek(fd, ma->offset, SEEK_SET) == ma->offset)
write(fd, buf, len);
}
close(fd);
}
static void
nfs2_call(u_int32_t xid, u_int32_t proc, u_char *buf, int len)
{
XDR xdrs;
struct diropargs dargs;
struct readargs rargs;
struct myreadargs *ma;
char *fname;
switch (proc) {
case NFSPROC_LOOKUP:
memset(&dargs, 0, sizeof(dargs));
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
if (xdr_diropargs(&xdrs, &dargs)) {
if (regex_match(dargs.name)) {
xid_map_enter(xid, NFS_PROGRAM, NFS_VERSION,
proc, (void *)dargs.name);
}
}
xdr_destroy(&xdrs);
break;
case NFSPROC_READ:
memset(&rargs, 0, sizeof(rargs));
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
if (xdr_readargs(&xdrs, &rargs)) {
fname = fh_map_find(rargs.file.data, NFS_FHSIZE);
if (fname != NULL) {
ma = (struct myreadargs *) malloc(sizeof(*ma));
if (ma != NULL) {
ma->filename = fname;
ma->offset = rargs.offset;
xid_map_enter(xid, NFS_PROGRAM,
NFS_VERSION,
NFSPROC_READ,
(void *)ma);
}
}
}
xdr_destroy(&xdrs);
break;
}
}
static void
nfs2_reply(struct xid_map *xm, struct tuple4 *addr, u_char *buf, int len)
{
XDR xdrs;
struct diropres dres;
struct readres rres;
switch (xm->proc) {
case NFSPROC_LOOKUP:
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
memset(&dres, 0, sizeof(dres));
if (xdr_diropres(&xdrs, &dres)) {
if (dres.status == NFS_OK)
fh_map_add((char *)xm->data,
dres.diropres_u.diropres.file.data,
NFS_FHSIZE);
}
xdr_destroy(&xdrs);
break;
case NFSPROC_READ:
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
memset(&rres, 0, sizeof(rres));
if (xdr_readres(&xdrs, &rres)) {
if (rres.status == NFS_OK) {
nfs_save(addr, (struct myreadargs *)xm->data,
rres.readres_u.reply.data.data_val,
rres.readres_u.reply.data.data_len);
}
}
xdr_destroy(&xdrs);
break;
}
}
static void
nfs3_call(u_int32_t xid, u_int32_t proc, u_char *buf, int len)
{
XDR xdrs;
struct LOOKUP3args largs;
struct READ3args rargs;
struct myreadargs *ma;
char *fname;
switch (proc) {
case NFSPROC3_LOOKUP:
memset(&largs, 0, sizeof(largs));
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
if (xdr_LOOKUP3args(&xdrs, &largs)) {
if (regex_match(largs.what.name)) {
xid_map_enter(xid, NFS_PROGRAM, NFS_V3,
proc, (void *)largs.what.name);
}
}
xdr_destroy(&xdrs);
break;
case NFSPROC3_READ:
memset(&rargs, 0, sizeof(rargs));
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
if (xdr_READ3args(&xdrs, &rargs)) {
fname = fh_map_find(rargs.file.data.data_val,
rargs.file.data.data_len);
if (fname != NULL) {
ma = (struct myreadargs *) malloc(sizeof(*ma));
if (ma != NULL) {
ma->filename = fname;
ma->offset = rargs.offset;
xid_map_enter(xid, NFS_PROGRAM, NFS_V3,
NFSPROC_READ,
(void *)ma);
}
}
}
xdr_destroy(&xdrs);
break;
}
}
static void
nfs3_reply(struct xid_map *xm, struct tuple4 *addr, u_char *buf, int len)
{
XDR xdrs;
struct LOOKUP3res lres;
struct READ3res rres;
switch (xm->proc) {
case NFSPROC3_LOOKUP:
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
memset(&lres, 0, sizeof(lres));
if (xdr_LOOKUP3res(&xdrs, &lres)) {
if (lres.status == NFS3_OK) {
fh_map_add((char *)xm->data,
lres.LOOKUP3res_u.resok.object.data.data_val,
lres.LOOKUP3res_u.resok.object.data.data_len);
}
}
xdr_destroy(&xdrs);
break;
case NFSPROC3_READ:
xdrmem_create(&xdrs, buf, len, XDR_DECODE);
memset(&rres, 0, sizeof(rres));
if (xdr_READ3res(&xdrs, &rres)) {
if (rres.status == NFS3_OK) {
nfs_save(addr, (struct myreadargs *)xm->data,
rres.READ3res_u.resok.data.data_val,
rres.READ3res_u.resok.data.data_len);
}
}
xdr_destroy(&xdrs);
break;
}
}
static void
decode_nfs(struct tuple4 *addr, u_char *buf, int len)
{
struct rpc_msg msg;
struct xid_map *xm;
int hdrlen;
memset(&msg, 0, sizeof(msg));
if ((hdrlen = rpc_decode(buf, len, &msg)) == 0)
return;
buf += hdrlen;
len -= hdrlen;
if (msg.rm_direction == CALL && msg.rm_call.cb_prog == NFS_PROGRAM) {
if (msg.rm_call.cb_vers == NFS_VERSION)
nfs2_call(msg.rm_xid, msg.rm_call.cb_proc, buf, len);
else if (msg.rm_call.cb_vers == NFS_V3)
nfs3_call(msg.rm_xid, msg.rm_call.cb_proc, buf, len);
}
else if ((xm = xid_map_find(msg.rm_xid)) != NULL &&
msg.rm_direction == REPLY &&
msg.rm_reply.rp_stat == MSG_ACCEPTED &&
msg.acpted_rply.ar_stat == SUCCESS) {
if (xm->vers == NFS_VERSION)
nfs2_reply(xm, addr, buf, len);
else if (xm->vers == NFS_V3)
nfs3_reply(xm, addr, buf, len);
free(xm->data);
memset(xm, 0, sizeof(*xm));
}
}
static void
decode_udp_nfs(struct libnet_ipv4_hdr *ip)
{
static struct tuple4 addr;
struct libnet_udp_hdr *udp;
u_char *buf;
int len, ip_hl = ip->ip_hl * 4;
len = ntohs(ip->ip_len) - ip_hl;
if (ip->ip_p != IPPROTO_UDP || len < sizeof(*udp))
return;
buf = (u_char *)ip + ip_hl;
udp = (struct libnet_udp_hdr *)buf;
if (ntohs(udp->uh_sport) != 2049 && ntohs(udp->uh_dport) != 2049)
return;
if (len != ntohs(udp->uh_ulen))
return;
buf += sizeof(*udp);
len -= sizeof(*udp);
addr.saddr = ip->ip_dst.s_addr;
addr.daddr = ip->ip_src.s_addr;
addr.source = ntohs(udp->uh_dport);
addr.dest = ntohs(udp->uh_sport);
decode_nfs(&addr, buf, len);
}
static int
decode_tcp_nfs_half(struct tuple4 *addr, struct half_stream *hs)
{
u_char *p, *buf;
int i, len, discard;
u_int32_t fraghdr;
buf = hs->data;
len = hs->count - hs->offset;
discard = 0;
for (p = buf; p + 4 < buf + len; ) {
fraghdr = pntohl(p);
p += 4 + FRAGLEN(fraghdr);
if (p > buf + len)
return (0);
if (LASTFRAG(fraghdr)) {
i = p - buf;
decode_nfs(addr, buf, i);
buf += i;
len -= i;
discard += i;
}
}
return (discard);
}
static void
decode_tcp_nfs(struct tcp_stream *ts, void **darth)
{
int len = 0;
if (ts->addr.dest != 2049 && ts->addr.source != 2049)
return;
switch (ts->nids_state) {
case NIDS_JUST_EST:
ts->server.collect = 1;
ts->client.collect = 1;
break;
case NIDS_DATA:
if (ts->server.count_new > 0) {
len = decode_tcp_nfs_half(&ts->addr, &ts->server);
}
else if (ts->client.count_new > 0) {
len = decode_tcp_nfs_half(&ts->addr, &ts->client);
}
nids_discard(ts, len);
break;
default:
if (ts->server.count > 0) {
decode_tcp_nfs_half(&ts->addr, &ts->server);
}
else if (ts->client.count > 0) {
decode_tcp_nfs_half(&ts->addr, &ts->client);
}
break;
}
}
static void
null_syslog(int type, int errnum, struct ip *iph, void *data)
{
}
int
main(int argc, char *argv[])
{
extern char *optarg;
extern int optind;
int c;
while ((c = getopt(argc, argv, "i:p:vh?V")) != -1) {
switch (c) {
case 'i':
nids_params.device = optarg;
break;
case 'p':
nids_params.filename = optarg;
break;
case 'v':
Opt_invert = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc > 0 && strlen(argv[0])) {
if ((pregex = (regex_t *) malloc(sizeof(*pregex))) == NULL)
err(1, "malloc");
if (regcomp(pregex, argv[0], REG_EXTENDED|REG_NOSUB) != 0)
errx(1, "invalid regular expression");
}
if (argc > 1)
nids_params.pcap_filter = copy_argv(argv + 1);
nids_params.scan_num_hosts = 0;
nids_params.syslog = null_syslog;
fh_map_init();
if (!nids_init())
errx(1, "nids_init: %s", nids_errbuf);
nids_register_ip(decode_udp_nfs);
nids_register_tcp(decode_tcp_nfs);
if (nids_params.pcap_filter != NULL) {
if (nids_params.filename == NULL) {
warnx("listening on %s [%s]", nids_params.device,
nids_params.pcap_filter);
}
else {
warnx("using %s [%s]", nids_params.filename,
nids_params.pcap_filter);
}
}
else {
if (nids_params.filename == NULL) {
warnx("listening on %s", nids_params.device);
}
else {
warnx("using %s", nids_params.filename);
}
}
nids_run();
/* NOTREACHED */
exit(0);
}
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