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262 lines (210 loc) · 6.15 KB
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/*
* Copyright (c) 2003 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <sys/param.h>
#include <sys/types.h>
#include "config.h"
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <sys/stat.h>
#include <sys/tree.h>
#include <sys/wait.h>
#include <sys/queue.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <dnet.h>
#include <ctype.h>
#include <assert.h>
#undef timeout_pending
#undef timeout_initialized
#include <event.h>
#include "honeyd.h"
#include "template.h"
#include "osfp.h"
#include "hooks.h"
struct pf_osfp_enlist;
int pfctl_file_fingerprints(int, int, const char *);
void pf_osfp_initialize(void);
int pf_osfp_match(struct pf_osfp_enlist *, pf_osfp_t);
struct pf_osfp_enlist *pf_osfp_fingerprint_hdr(const struct ip_hdr *, const struct tcp_hdr *);
void honeyd_osfp_input(struct tuple *, u_char *, u_int, void *);
static struct osfp *honeyd_osfp_cache(const struct ip_hdr *);
SPLAY_HEAD(osfptree, osfp) osfp_buckets[OSFP_HASHSIZE];
int
osfp_compare(struct osfp *a, struct osfp *b)
{
if (a->src < b->src)
return (-1);
else if (a->src > b->src)
return (1);
return (0);
}
SPLAY_PROTOTYPE(osfptree, osfp, node, osfp_compare);
SPLAY_GENERATE(osfptree, osfp, node, osfp_compare);
int
honeyd_osfp_init(const char *filename)
{
int i;
pf_osfp_initialize();
if (pfctl_file_fingerprints(0, 0, filename) != 0)
return (-1);
/* Add a hooks entry so that we get TCP input packets */
hooks_add_packet_hook(IP_PROTO_TCP, HD_INCOMING,
honeyd_osfp_input, NULL);
/* Initialize hash buckets */
for (i = 0; i < OSFP_HASHSIZE; i++)
SPLAY_INIT(&osfp_buckets[i]);
return (0);
}
static struct osfptree *
honeyd_osfp_hash(const struct ip_hdr *ip)
{
struct osfptree *root;
int i;
u_char *bin;
u_char h = 0;
bin = (u_char *)&ip->ip_src;
for (i = 0; i < sizeof(ip->ip_src); i++)
h ^= *bin++;
root = &osfp_buckets[h & (OSFP_HASHSIZE - 1)];
return (root);
}
void
honeyd_osfp_timeout(int fd, short what, void *arg)
{
struct osfp *entry = arg;
struct osfptree *root;
struct ip_hdr ip;
struct addr src;
addr_pack(&src, ADDR_TYPE_IP, IP_ADDR_BITS, &entry->src, IP_ADDR_LEN);
syslog(LOG_DEBUG, "Expiring OS fingerprint for %s", addr_ntoa(&src));
ip.ip_src = entry->src;
root = honeyd_osfp_hash(&ip);
SPLAY_REMOVE(osfptree, root, entry);
free(entry);
}
static void
honeyd_osfp_cache_insert(const struct ip_hdr *ip, struct pf_osfp_enlist *list)
{
struct timeval tv;
struct osfptree *root;
struct osfp *entry;
/* Create a new entry unless we have it cached already */
if ((entry = honeyd_osfp_cache(ip)) == NULL) {
if ((entry = calloc(1, sizeof(struct osfp))) == NULL) {
warn("%s: calloc", __func__);
return;
}
entry->src = ip->ip_src;
entry->timeout = evtimer_new(libevent_base, honeyd_osfp_timeout, entry);
root = honeyd_osfp_hash(ip);
SPLAY_INSERT(osfptree, root, entry);
}
entry->list = list;
timerclear(&tv);
tv.tv_sec = OSFP_TIMEOUT;
evtimer_add(entry->timeout, &tv);
}
static struct osfp *
honeyd_osfp_cache(const struct ip_hdr *ip)
{
struct timeval tv;
struct osfptree *root;
struct osfp tmp, *entry;
root = honeyd_osfp_hash(ip);
tmp.src = ip->ip_src;
entry = SPLAY_FIND(osfptree, root, &tmp);
if (entry == NULL)
return (NULL);
assert(entry->src == ip->ip_src);
/* Update timeout */
timerclear(&tv);
tv.tv_sec = OSFP_TIMEOUT;
evtimer_add(entry->timeout, &tv);
return (entry);
}
int
honeyd_osfp_match(const struct ip_hdr *ip, pf_osfp_t fp)
{
struct pf_osfp_enlist *list;
const struct tcp_hdr *tcp;
tcp = (const struct tcp_hdr *)((u_char *)ip + (ip->ip_hl << 2));
list = pf_osfp_fingerprint_hdr(ip, tcp);
if (list == NULL) {
struct osfp *entry = honeyd_osfp_cache(ip);
if (entry != NULL)
list = entry->list;
}
return (pf_osfp_match(list, fp));
}
void
honeyd_osfp_input(struct tuple *conhdr, u_char *pkt, u_int plen, void *arg)
{
const struct ip_hdr *ip = (struct ip_hdr *)pkt;
const struct tcp_hdr *tcp;
struct pf_osfp_enlist *list;
u_short iphlen = ip->ip_hl << 2;
/* Sanity check */
if (iphlen + sizeof(struct tcp_hdr) > plen)
return;
tcp = (const struct tcp_hdr *)(pkt + iphlen);
/* Only intercept syn packets */
if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
return;
list = pf_osfp_fingerprint_hdr(ip, tcp);
if (list == NULL)
return;
honeyd_osfp_cache_insert(ip, list);
}
char *
honeyd_osfp_name(struct ip_hdr *ip)
{
static char name[128];
struct osfp *cache;
struct pf_osfp_enlist *list;
struct pf_osfp_entry *entry;
cache = honeyd_osfp_cache(ip);
if (cache == NULL)
return (NULL);
list = cache->list;
entry = SLIST_FIRST(list);
snprintf(name, sizeof(name), "%s %s %s",
entry->fp_class_nm,
entry->fp_version_nm,
entry->fp_subtype_nm);
return (name);
}