Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.sbin/tcpdump/../../sys/net/pf_osfp.c	Lines:	0	210	0.0 %
Date:	2017-11-13	Branches:	0	193	0.0 %


/*	$OpenBSD: pf_osfp.c,v 1.40 2017/04/23 11:37:11 sthen Exp $ */

/*
 * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include <sys/param.h>
#include <sys/socket.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/pool.h>
#endif /* _KERNEL */
#include <sys/queue.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>

#ifdef INET6
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#endif /* INET6 */

#include <net/pfvar.h>
#include <net/pfvar_priv.h>

#ifdef _KERNEL
typedef struct pool pool_t;

#else	/* !_KERNEL */
/* Userland equivalents so we can lend code to tcpdump et al. */

#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#define pool_t			int
#define pool_get(pool, flags)	malloc(*(pool))
#define pool_put(pool, item)	free(item)
#define pool_init(pool, size, a, ao, f, m, p)	(*(pool)) = (size)

#ifdef PFDEBUG
#include <sys/stdarg.h>	/* for DPFPRINTF() */
#endif /* PFDEBUG */

#endif /* _KERNEL */

SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
pool_t pf_osfp_entry_pl;
pool_t pf_osfp_pl;

struct pf_os_fingerprint	*pf_osfp_find(struct pf_osfp_list *,
				    struct pf_os_fingerprint *, u_int8_t);
struct pf_os_fingerprint	*pf_osfp_find_exact(struct pf_osfp_list *,
				    struct pf_os_fingerprint *);
void				 pf_osfp_insert(struct pf_osfp_list *,
				    struct pf_os_fingerprint *);


#ifdef _KERNEL
/*
 * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
 * Returns the list of possible OSes.
 */
struct pf_osfp_enlist *
pf_osfp_fingerprint(struct pf_pdesc *pd)
{
	struct tcphdr	*th = &pd->hdr.tcp;
	struct ip	*ip = NULL;
	struct ip6_hdr	*ip6 = NULL;
	char		 hdr[60];

	if (pd->proto != IPPROTO_TCP)
		return (NULL);

	switch (pd->af) {
	case AF_INET:
		ip = mtod(pd->m, struct ip *);
		break;
	case AF_INET6:
		ip6 = mtod(pd->m, struct ip6_hdr *);
		break;
	}
	if (!pf_pull_hdr(pd->m, pd->off, hdr, th->th_off << 2, NULL, NULL,
	    pd->af))
		return (NULL);

	return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
}
#endif /* _KERNEL */

struct pf_osfp_enlist *
pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6,
    const struct tcphdr *tcp)
{
	struct pf_os_fingerprint fp, *fpresult;
	int cnt, optlen = 0;
	const u_int8_t *optp;
#ifdef _KERNEL
	char srcname[128];
#else	/* !_KERNEL */
	char srcname[NI_MAXHOST];
#endif	/* _KERNEL */

	if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
		return (NULL);
	if (ip) {
		if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
			return (NULL);
	}

	memset(&fp, 0, sizeof(fp));

	if (ip) {
#ifndef _KERNEL
		struct sockaddr_in sin;
#endif	/* _KERNEL */

		fp.fp_psize = ntohs(ip->ip_len);
		fp.fp_ttl = ip->ip_ttl;
		if (ip->ip_off & htons(IP_DF))
			fp.fp_flags |= PF_OSFP_DF;
#ifdef _KERNEL
		inet_ntop(AF_INET, &ip->ip_src, srcname, sizeof(srcname));
#else	/* !_KERNEL */
		memset(&sin, 0, sizeof(sin));
		sin.sin_family = AF_INET;
		sin.sin_len = sizeof(struct sockaddr_in);
		sin.sin_addr = ip->ip_src;
		(void)getnameinfo((struct sockaddr *)&sin,
		    sizeof(struct sockaddr_in), srcname, sizeof(srcname),
		    NULL, 0, NI_NUMERICHOST);
#endif	/* _KERNEL */
	}
#ifdef INET6
	else if (ip6) {
#ifndef _KERNEL
		struct sockaddr_in6 sin6;
#endif	/* !_KERNEL */

		/* jumbo payload? */
		fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
		fp.fp_ttl = ip6->ip6_hlim;
		fp.fp_flags |= PF_OSFP_DF;
		fp.fp_flags |= PF_OSFP_INET6;
#ifdef _KERNEL
		inet_ntop(AF_INET6, &ip6->ip6_src, srcname, sizeof(srcname));
#else	/* !_KERNEL */
		memset(&sin6, 0, sizeof(sin6));
		sin6.sin6_family = AF_INET6;
		sin6.sin6_len = sizeof(struct sockaddr_in6);
		sin6.sin6_addr = ip6->ip6_src;
		(void)getnameinfo((struct sockaddr *)&sin6,
		    sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
		    NULL, 0, NI_NUMERICHOST);
#endif	/* !_KERNEL */
	}
#endif	/* INET6 */
	else
		return (NULL);
	fp.fp_wsize = ntohs(tcp->th_win);


	cnt = (tcp->th_off << 2) - sizeof(*tcp);
	optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
	for (; cnt > 0; cnt -= optlen, optp += optlen) {
		if (*optp == TCPOPT_EOL)
			break;

		fp.fp_optcnt++;
		if (*optp == TCPOPT_NOP) {
			fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
			    PF_OSFP_TCPOPT_NOP;
			optlen = 1;
		} else {
			if (cnt < 2)
				return (NULL);
			optlen = optp[1];
			if (optlen > cnt || optlen < 2)
				return (NULL);
			switch (*optp) {
			case TCPOPT_MAXSEG:
				if (optlen >= TCPOLEN_MAXSEG)
					memcpy(&fp.fp_mss, &optp[2],
					    sizeof(fp.fp_mss));
				fp.fp_tcpopts = (fp.fp_tcpopts <<
				    PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
				fp.fp_mss = ntohs(fp.fp_mss);
				break;
			case TCPOPT_WINDOW:
				if (optlen >= TCPOLEN_WINDOW)
					memcpy(&fp.fp_wscale, &optp[2],
					    sizeof(fp.fp_wscale));
				fp.fp_tcpopts = (fp.fp_tcpopts <<
				    PF_OSFP_TCPOPT_BITS) |
				    PF_OSFP_TCPOPT_WSCALE;
				break;
			case TCPOPT_SACK_PERMITTED:
				fp.fp_tcpopts = (fp.fp_tcpopts <<
				    PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
				break;
			case TCPOPT_TIMESTAMP:
				if (optlen >= TCPOLEN_TIMESTAMP) {
					u_int32_t ts;
					memcpy(&ts, &optp[2], sizeof(ts));
					if (ts == 0)
						fp.fp_flags |= PF_OSFP_TS0;

				}
				fp.fp_tcpopts = (fp.fp_tcpopts <<
				    PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
				break;
			default:
				return (NULL);
			}
		}
		optlen = MAX(optlen, 1);	/* paranoia */
	}

	DPFPRINTF(LOG_INFO,
	    "fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
	    "(TS=%s,M=%s%d,W=%s%d)",
	    srcname, ntohs(tcp->th_sport),
	    fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
	    fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
	    (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
	    (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
	    (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
	    fp.fp_mss,
	    (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
	    (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
	    fp.fp_wscale);

	if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
	    PF_OSFP_MAXTTL_OFFSET)))
		return (&fpresult->fp_oses);
	return (NULL);
}

/* Match a fingerprint ID against a list of OSes */
int
pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
{
	struct pf_osfp_entry *entry;
	int os_class, os_version, os_subtype;
	int en_class, en_version, en_subtype;

	if (os == PF_OSFP_ANY)
		return (1);
	if (list == NULL) {
		DPFPRINTF(LOG_INFO, "osfp no match against %x", os);
		return (os == PF_OSFP_UNKNOWN);
	}
	PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
	SLIST_FOREACH(entry, list, fp_entry) {
		PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
		if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
		    (os_version == PF_OSFP_ANY || en_version == os_version) &&
		    (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
			DPFPRINTF(LOG_INFO,
			    "osfp matched %s %s %s  %x==%x",
			    entry->fp_class_nm, entry->fp_version_nm,
			    entry->fp_subtype_nm, os, entry->fp_os);
			return (1);
		}
	}
	DPFPRINTF(LOG_INFO, "fingerprint 0x%x didn't match", os);
	return (0);
}

/* Initialize the OS fingerprint system */
void
pf_osfp_initialize(void)
{
	pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0,
	    IPL_NONE, PR_WAITOK, "pfosfpen", NULL);
	pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0,
	    IPL_NONE, PR_WAITOK, "pfosfp", NULL);
	SLIST_INIT(&pf_osfp_list);
}

/* Flush the fingerprint list */
void
pf_osfp_flush(void)
{
	struct pf_os_fingerprint *fp;
	struct pf_osfp_entry *entry;

	while ((fp = SLIST_FIRST(&pf_osfp_list))) {
		SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
		while ((entry = SLIST_FIRST(&fp->fp_oses))) {
			SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
			pool_put(&pf_osfp_entry_pl, entry);
		}
		pool_put(&pf_osfp_pl, fp);
	}
}


/* Add a fingerprint */
int
pf_osfp_add(struct pf_osfp_ioctl *fpioc)
{
	struct pf_os_fingerprint *fp, fpadd;
	struct pf_osfp_entry *entry;

	memset(&fpadd, 0, sizeof(fpadd));
	fpadd.fp_tcpopts = fpioc->fp_tcpopts;
	fpadd.fp_wsize = fpioc->fp_wsize;
	fpadd.fp_psize = fpioc->fp_psize;
	fpadd.fp_mss = fpioc->fp_mss;
	fpadd.fp_flags = fpioc->fp_flags;
	fpadd.fp_optcnt = fpioc->fp_optcnt;
	fpadd.fp_wscale = fpioc->fp_wscale;
	fpadd.fp_ttl = fpioc->fp_ttl;

	DPFPRINTF(LOG_DEBUG,
	    "adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
	    "(TS=%s,M=%s%d,W=%s%d) %x",
	    fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
	    fpioc->fp_os.fp_subtype_nm,
	    (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
	    (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
	    (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
	    (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
	    fpadd.fp_wsize,
	    fpadd.fp_ttl,
	    (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
	    (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
	    (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
	    fpadd.fp_psize,
	    (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
	    (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
	    (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
	    (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
	    fpadd.fp_mss,
	    (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
	    (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
	    fpadd.fp_wscale,
	    fpioc->fp_os.fp_os);

	if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
		 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
			if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
				return (EEXIST);
		}
		if ((entry = pool_get(&pf_osfp_entry_pl,
		    PR_WAITOK|PR_LIMITFAIL)) == NULL)
			return (ENOMEM);
	} else {
		if ((fp = pool_get(&pf_osfp_pl,
		    PR_WAITOK|PR_ZERO|PR_LIMITFAIL)) == NULL)
			return (ENOMEM);
		fp->fp_tcpopts = fpioc->fp_tcpopts;
		fp->fp_wsize = fpioc->fp_wsize;
		fp->fp_psize = fpioc->fp_psize;
		fp->fp_mss = fpioc->fp_mss;
		fp->fp_flags = fpioc->fp_flags;
		fp->fp_optcnt = fpioc->fp_optcnt;
		fp->fp_wscale = fpioc->fp_wscale;
		fp->fp_ttl = fpioc->fp_ttl;
		SLIST_INIT(&fp->fp_oses);
		if ((entry = pool_get(&pf_osfp_entry_pl,
		    PR_WAITOK|PR_LIMITFAIL)) == NULL) {
			pool_put(&pf_osfp_pl, fp);
			return (ENOMEM);
		}
		pf_osfp_insert(&pf_osfp_list, fp);
	}
	memcpy(entry, &fpioc->fp_os, sizeof(*entry));

	/* Make sure the strings are NUL terminated */
	entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
	entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
	entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';

	SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);

#ifdef PFDEBUG
	if ((fp = pf_osfp_validate()))
		DPFPRINTF(LOG_NOTICE,
		    "Invalid fingerprint list");
#endif /* PFDEBUG */
	return (0);
}


/* Find a fingerprint in the list */
struct pf_os_fingerprint *
pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
    u_int8_t ttldiff)
{
	struct pf_os_fingerprint *f;

#define MATCH_INT(_MOD, _DC, _field)					\
	if ((f->fp_flags & _DC) == 0) {					\
		if ((f->fp_flags & _MOD) == 0) {			\
			if (f->_field != find->_field)			\
				continue;				\
		} else {						\
			if (f->_field == 0 || find->_field % f->_field)	\
				continue;				\
		}							\
	}

	SLIST_FOREACH(f, list, fp_next) {
		if (f->fp_tcpopts != find->fp_tcpopts ||
		    f->fp_optcnt != find->fp_optcnt ||
		    f->fp_ttl < find->fp_ttl ||
		    f->fp_ttl - find->fp_ttl > ttldiff ||
		    (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
		    (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
			continue;

		MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
		MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
		MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
		if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
			if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
				if (find->fp_mss == 0)
					continue;

/* Some "smart" NAT devices and DSL routers will tweak the MSS size and
 * will set it to whatever is suitable for the link type.
 */
#define SMART_MSS	1460
				if ((find->fp_wsize % find->fp_mss ||
				    find->fp_wsize / find->fp_mss !=
				    f->fp_wsize) &&
				    (find->fp_wsize % SMART_MSS ||
				    find->fp_wsize / SMART_MSS !=
				    f->fp_wsize))
					continue;
			} else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
				if (find->fp_mss == 0)
					continue;

#define MTUOFF	(sizeof(struct ip) + sizeof(struct tcphdr))
#define SMART_MTU	(SMART_MSS + MTUOFF)
				if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
				    find->fp_wsize / (find->fp_mss + MTUOFF) !=
				    f->fp_wsize) &&
				    (find->fp_wsize % SMART_MTU ||
				    find->fp_wsize / SMART_MTU !=
				    f->fp_wsize))
					continue;
			} else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
				if (f->fp_wsize == 0 || find->fp_wsize %
				    f->fp_wsize)
					continue;
			} else {
				if (f->fp_wsize != find->fp_wsize)
					continue;
			}
		}
		return (f);
	}

	return (NULL);
}

/* Find an exact fingerprint in the list */
struct pf_os_fingerprint *
pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
{
	struct pf_os_fingerprint *f;

	SLIST_FOREACH(f, list, fp_next) {
		if (f->fp_tcpopts == find->fp_tcpopts &&
		    f->fp_wsize == find->fp_wsize &&
		    f->fp_psize == find->fp_psize &&
		    f->fp_mss == find->fp_mss &&
		    f->fp_flags == find->fp_flags &&
		    f->fp_optcnt == find->fp_optcnt &&
		    f->fp_wscale == find->fp_wscale &&
		    f->fp_ttl == find->fp_ttl)
			return (f);
	}

	return (NULL);
}

/* Insert a fingerprint into the list */
void
pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
{
	struct pf_os_fingerprint *f, *prev = NULL;

	/* XXX need to go semi tree based.  can key on tcp options */

	SLIST_FOREACH(f, list, fp_next)
		prev = f;
	if (prev)
		SLIST_INSERT_AFTER(prev, ins, fp_next);
	else
		SLIST_INSERT_HEAD(list, ins, fp_next);
}

/* Fill a fingerprint by its number (from an ioctl) */
int
pf_osfp_get(struct pf_osfp_ioctl *fpioc)
{
	struct pf_os_fingerprint *fp;
	struct pf_osfp_entry *entry;
	int num = fpioc->fp_getnum;
	int i = 0;


	memset(fpioc, 0, sizeof(*fpioc));
	SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
		SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
			if (i++ == num) {
				fpioc->fp_mss = fp->fp_mss;
				fpioc->fp_wsize = fp->fp_wsize;
				fpioc->fp_flags = fp->fp_flags;
				fpioc->fp_psize = fp->fp_psize;
				fpioc->fp_ttl = fp->fp_ttl;
				fpioc->fp_wscale = fp->fp_wscale;
				fpioc->fp_getnum = num;
				memcpy(&fpioc->fp_os, entry,
				    sizeof(fpioc->fp_os));
				return (0);
			}
		}
	}

	return (EBUSY);
}


/* Validate that each signature is reachable */
struct pf_os_fingerprint *
pf_osfp_validate(void)
{
	struct pf_os_fingerprint *f, *f2, find;

	SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
		memcpy(&find, f, sizeof(find));

		/* We do a few MSS/th_win percolations to make things unique */
		if (find.fp_mss == 0)
			find.fp_mss = 128;
		if (f->fp_flags & PF_OSFP_WSIZE_MSS)
			find.fp_wsize *= find.fp_mss;
		else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
			find.fp_wsize *= (find.fp_mss + 40);
		else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
			find.fp_wsize *= 2;
		if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
			if (f2)
				DPFPRINTF(LOG_NOTICE,
				    "Found \"%s %s %s\" instead of "
				    "\"%s %s %s\"\n",
				    SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
				    SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
				    SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
				    SLIST_FIRST(&f->fp_oses)->fp_class_nm,
				    SLIST_FIRST(&f->fp_oses)->fp_version_nm,
				    SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
			else
				DPFPRINTF(LOG_NOTICE,
				    "Couldn't find \"%s %s %s\"\n",
				    SLIST_FIRST(&f->fp_oses)->fp_class_nm,
				    SLIST_FIRST(&f->fp_oses)->fp_version_nm,
				    SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
			return (f);
		}
	}
	return (NULL);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: pf_osfp.c,v 1.40 2017/04/23 11:37:11 sthen Exp $ */
2
3			/*
4			* Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
5			*
6			* Permission to use, copy, modify, and distribute this software for any
7			* purpose with or without fee is hereby granted, provided that the above
8			* copyright notice and this permission notice appear in all copies.
9			*
10			* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11			* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12			* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13			* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14			* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15			* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16			* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17			*
18			*/
19
20			#include <sys/param.h>
21			#include <sys/socket.h>
22			#ifdef _KERNEL
23			#include <sys/systm.h>
24			#include <sys/pool.h>
25			#endif /* _KERNEL */
26			#include <sys/queue.h>
27			#include <sys/mbuf.h>
28			#include <sys/syslog.h>
29
30			#include <net/if.h>
31
32			#include <netinet/in.h>
33			#include <netinet/ip.h>
34			#include <netinet/ip_icmp.h>
35			#include <netinet/tcp.h>
36			#include <netinet/udp.h>
37
38			#ifdef INET6
39			#include <netinet/ip6.h>
40			#include <netinet/icmp6.h>
41			#endif /* INET6 */
42
43			#include <net/pfvar.h>
44			#include <net/pfvar_priv.h>
45
46			#ifdef _KERNEL
47			typedef struct pool pool_t;
48
49			#else /* !_KERNEL */
50			/* Userland equivalents so we can lend code to tcpdump et al. */
51
52			#include <arpa/inet.h>
53			#include <errno.h>
54			#include <stdio.h>
55			#include <stdlib.h>
56			#include <string.h>
57			#include <netdb.h>
58			#define pool_t int
59			#define pool_get(pool, flags) malloc(*(pool))
60			#define pool_put(pool, item) free(item)
61			#define pool_init(pool, size, a, ao, f, m, p) (*(pool)) = (size)
62
63			#ifdef PFDEBUG
64			#include <sys/stdarg.h> /* for DPFPRINTF() */
65			#endif /* PFDEBUG */
66
67			#endif /* _KERNEL */
68
69			SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
70			pool_t pf_osfp_entry_pl;
71			pool_t pf_osfp_pl;
72
73			struct pf_os_fingerprint pf_osfp_find(struct pf_osfp_list ,
74			struct pf_os_fingerprint *, u_int8_t);
75			struct pf_os_fingerprint pf_osfp_find_exact(struct pf_osfp_list ,
76			struct pf_os_fingerprint *);
77			void pf_osfp_insert(struct pf_osfp_list *,
78			struct pf_os_fingerprint *);
79
80
81			#ifdef _KERNEL
82			/*
83			* Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
84			* Returns the list of possible OSes.
85			*/
86			struct pf_osfp_enlist *
87			pf_osfp_fingerprint(struct pf_pdesc *pd)
88			{
89			struct tcphdr *th = &pd->hdr.tcp;
90			struct ip *ip = NULL;
91			struct ip6_hdr *ip6 = NULL;
92			char hdr[60];
93
94			if (pd->proto != IPPROTO_TCP)
95			return (NULL);
96
97			switch (pd->af) {
98			case AF_INET:
99			ip = mtod(pd->m, struct ip *);
100			break;
101			case AF_INET6:
102			ip6 = mtod(pd->m, struct ip6_hdr *);
103			break;
104			}
105			if (!pf_pull_hdr(pd->m, pd->off, hdr, th->th_off << 2, NULL, NULL,
106			pd->af))
107			return (NULL);
108
109			return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
110			}
111			#endif /* _KERNEL */
112
113			struct pf_osfp_enlist *
114			pf_osfp_fingerprint_hdr(const struct ip ip, const struct ip6_hdr ip6,
115			const struct tcphdr *tcp)
116			{
117			struct pf_os_fingerprint fp, *fpresult;
118			int cnt, optlen = 0;
119			const u_int8_t *optp;
120			#ifdef _KERNEL
121			char srcname[128];
122			#else /* !_KERNEL */
123			char srcname[NI_MAXHOST];
124			#endif /* _KERNEL */
125
126			if ((tcp->th_flags & (TH_SYN\|TH_ACK)) != TH_SYN)
127			return (NULL);
128			if (ip) {
129			if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
130			return (NULL);
131			}
132
133			memset(&fp, 0, sizeof(fp));
134
135			if (ip) {
136			#ifndef _KERNEL
137			struct sockaddr_in sin;
138			#endif /* _KERNEL */
139
140			fp.fp_psize = ntohs(ip->ip_len);
141			fp.fp_ttl = ip->ip_ttl;
142			if (ip->ip_off & htons(IP_DF))
143			fp.fp_flags \|= PF_OSFP_DF;
144			#ifdef _KERNEL
145			inet_ntop(AF_INET, &ip->ip_src, srcname, sizeof(srcname));
146			#else /* !_KERNEL */
147			memset(&sin, 0, sizeof(sin));
148			sin.sin_family = AF_INET;
149			sin.sin_len = sizeof(struct sockaddr_in);
150			sin.sin_addr = ip->ip_src;
151			(void)getnameinfo((struct sockaddr *)&sin,
152			sizeof(struct sockaddr_in), srcname, sizeof(srcname),
153			NULL, 0, NI_NUMERICHOST);
154			#endif /* _KERNEL */
155			}
156			#ifdef INET6
157			else if (ip6) {
158			#ifndef _KERNEL
159			struct sockaddr_in6 sin6;
160			#endif /* !_KERNEL */
161
162			/* jumbo payload? */
163			fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
164			fp.fp_ttl = ip6->ip6_hlim;
165			fp.fp_flags \|= PF_OSFP_DF;
166			fp.fp_flags \|= PF_OSFP_INET6;
167			#ifdef _KERNEL
168			inet_ntop(AF_INET6, &ip6->ip6_src, srcname, sizeof(srcname));
169			#else /* !_KERNEL */
170			memset(&sin6, 0, sizeof(sin6));
171			sin6.sin6_family = AF_INET6;
172			sin6.sin6_len = sizeof(struct sockaddr_in6);
173			sin6.sin6_addr = ip6->ip6_src;
174			(void)getnameinfo((struct sockaddr *)&sin6,
175			sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
176			NULL, 0, NI_NUMERICHOST);
177			#endif /* !_KERNEL */
178			}
179			#endif /* INET6 */
180			else
181			return (NULL);
182			fp.fp_wsize = ntohs(tcp->th_win);
183
184
185			cnt = (tcp->th_off << 2) - sizeof(*tcp);
186			optp = (const u_int8_t )((const char )tcp + sizeof(*tcp));
187			for (; cnt > 0; cnt -= optlen, optp += optlen) {
188			if (*optp == TCPOPT_EOL)
189			break;
190
191			fp.fp_optcnt++;
192			if (*optp == TCPOPT_NOP) {
193			fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) \|
194			PF_OSFP_TCPOPT_NOP;
195			optlen = 1;
196			} else {
197			if (cnt < 2)
198			return (NULL);
199			optlen = optp[1];
200			if (optlen > cnt \|\| optlen < 2)
201			return (NULL);
202			switch (*optp) {
203			case TCPOPT_MAXSEG:
204			if (optlen >= TCPOLEN_MAXSEG)
205			memcpy(&fp.fp_mss, &optp[2],
206			sizeof(fp.fp_mss));
207			fp.fp_tcpopts = (fp.fp_tcpopts <<
208			PF_OSFP_TCPOPT_BITS) \| PF_OSFP_TCPOPT_MSS;
209			fp.fp_mss = ntohs(fp.fp_mss);
210			break;
211			case TCPOPT_WINDOW:
212			if (optlen >= TCPOLEN_WINDOW)
213			memcpy(&fp.fp_wscale, &optp[2],
214			sizeof(fp.fp_wscale));
215			fp.fp_tcpopts = (fp.fp_tcpopts <<
216			PF_OSFP_TCPOPT_BITS) \|
217			PF_OSFP_TCPOPT_WSCALE;
218			break;
219			case TCPOPT_SACK_PERMITTED:
220			fp.fp_tcpopts = (fp.fp_tcpopts <<
221			PF_OSFP_TCPOPT_BITS) \| PF_OSFP_TCPOPT_SACK;
222			break;
223			case TCPOPT_TIMESTAMP:
224			if (optlen >= TCPOLEN_TIMESTAMP) {
225			u_int32_t ts;
226			memcpy(&ts, &optp[2], sizeof(ts));
227			if (ts == 0)
228			fp.fp_flags \|= PF_OSFP_TS0;
229
230			}
231			fp.fp_tcpopts = (fp.fp_tcpopts <<
232			PF_OSFP_TCPOPT_BITS) \| PF_OSFP_TCPOPT_TS;
233			break;
234			default:
235			return (NULL);
236			}
237			}
238			optlen = MAX(optlen, 1); /* paranoia */
239			}
240
241			DPFPRINTF(LOG_INFO,
242			"fingerprinted %s:%d %d:%d:%d:%d:%llx (%d) "
243			"(TS=%s,M=%s%d,W=%s%d)",
244			srcname, ntohs(tcp->th_sport),
245			fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
246			fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
247			(fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
248			(fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
249			(fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
250			fp.fp_mss,
251			(fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
252			(fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
253			fp.fp_wscale);
254
255			if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
256			PF_OSFP_MAXTTL_OFFSET)))
257			return (&fpresult->fp_oses);
258			return (NULL);
259			}
260
261			/* Match a fingerprint ID against a list of OSes */
262			int
263			pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
264			{
265			struct pf_osfp_entry *entry;
266			int os_class, os_version, os_subtype;
267			int en_class, en_version, en_subtype;
268
269			if (os == PF_OSFP_ANY)
270			return (1);
271			if (list == NULL) {
272			DPFPRINTF(LOG_INFO, "osfp no match against %x", os);
273			return (os == PF_OSFP_UNKNOWN);
274			}
275			PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
276			SLIST_FOREACH(entry, list, fp_entry) {
277			PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
278			if ((os_class == PF_OSFP_ANY \|\| en_class == os_class) &&
279			(os_version == PF_OSFP_ANY \|\| en_version == os_version) &&
280			(os_subtype == PF_OSFP_ANY \|\| en_subtype == os_subtype)) {
281			DPFPRINTF(LOG_INFO,
282			"osfp matched %s %s %s %x==%x",
283			entry->fp_class_nm, entry->fp_version_nm,
284			entry->fp_subtype_nm, os, entry->fp_os);
285			return (1);
286			}
287			}
288			DPFPRINTF(LOG_INFO, "fingerprint 0x%x didn't match", os);
289			return (0);
290			}
291
292			/* Initialize the OS fingerprint system */
293			void
294			pf_osfp_initialize(void)
295			{
296			pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0,
297			IPL_NONE, PR_WAITOK, "pfosfpen", NULL);
298			pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0,
299			IPL_NONE, PR_WAITOK, "pfosfp", NULL);
300			SLIST_INIT(&pf_osfp_list);
301			}
302
303			/* Flush the fingerprint list */
304			void
305			pf_osfp_flush(void)
306			{
307			struct pf_os_fingerprint *fp;
308			struct pf_osfp_entry *entry;
309
310			while ((fp = SLIST_FIRST(&pf_osfp_list))) {
311			SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
312			while ((entry = SLIST_FIRST(&fp->fp_oses))) {
313			SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
314			pool_put(&pf_osfp_entry_pl, entry);
315			}
316			pool_put(&pf_osfp_pl, fp);
317			}
318			}
319
320
321			/* Add a fingerprint */
322			int
323			pf_osfp_add(struct pf_osfp_ioctl *fpioc)
324			{
325			struct pf_os_fingerprint *fp, fpadd;
326			struct pf_osfp_entry *entry;
327
328			memset(&fpadd, 0, sizeof(fpadd));
329			fpadd.fp_tcpopts = fpioc->fp_tcpopts;
330			fpadd.fp_wsize = fpioc->fp_wsize;
331			fpadd.fp_psize = fpioc->fp_psize;
332			fpadd.fp_mss = fpioc->fp_mss;
333			fpadd.fp_flags = fpioc->fp_flags;
334			fpadd.fp_optcnt = fpioc->fp_optcnt;
335			fpadd.fp_wscale = fpioc->fp_wscale;
336			fpadd.fp_ttl = fpioc->fp_ttl;
337
338			DPFPRINTF(LOG_DEBUG,
339			"adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
340			"(TS=%s,M=%s%d,W=%s%d) %x",
341			fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
342			fpioc->fp_os.fp_subtype_nm,
343			(fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
344			(fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
345			(fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
346			(fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
347			fpadd.fp_wsize,
348			fpadd.fp_ttl,
349			(fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
350			(fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
351			(fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
352			fpadd.fp_psize,
353			(long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
354			(fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
355			(fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
356			(fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
357			fpadd.fp_mss,
358			(fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
359			(fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
360			fpadd.fp_wscale,
361			fpioc->fp_os.fp_os);
362
363			if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
364			SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
365			if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
366			return (EEXIST);
367			}
368			if ((entry = pool_get(&pf_osfp_entry_pl,
369			PR_WAITOK\|PR_LIMITFAIL)) == NULL)
370			return (ENOMEM);
371			} else {
372			if ((fp = pool_get(&pf_osfp_pl,
373			PR_WAITOK\|PR_ZERO\|PR_LIMITFAIL)) == NULL)
374			return (ENOMEM);
375			fp->fp_tcpopts = fpioc->fp_tcpopts;
376			fp->fp_wsize = fpioc->fp_wsize;
377			fp->fp_psize = fpioc->fp_psize;
378			fp->fp_mss = fpioc->fp_mss;
379			fp->fp_flags = fpioc->fp_flags;
380			fp->fp_optcnt = fpioc->fp_optcnt;
381			fp->fp_wscale = fpioc->fp_wscale;
382			fp->fp_ttl = fpioc->fp_ttl;
383			SLIST_INIT(&fp->fp_oses);
384			if ((entry = pool_get(&pf_osfp_entry_pl,
385			PR_WAITOK\|PR_LIMITFAIL)) == NULL) {
386			pool_put(&pf_osfp_pl, fp);
387			return (ENOMEM);
388			}
389			pf_osfp_insert(&pf_osfp_list, fp);
390			}
391			memcpy(entry, &fpioc->fp_os, sizeof(*entry));
392
393			/* Make sure the strings are NUL terminated */
394			entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
395			entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
396			entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
397
398			SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
399
400			#ifdef PFDEBUG
401			if ((fp = pf_osfp_validate()))
402			DPFPRINTF(LOG_NOTICE,
403			"Invalid fingerprint list");
404			#endif /* PFDEBUG */
405			return (0);
406			}
407
408
409			/* Find a fingerprint in the list */
410			struct pf_os_fingerprint *
411			pf_osfp_find(struct pf_osfp_list list, struct pf_os_fingerprint find,
412			u_int8_t ttldiff)
413			{
414			struct pf_os_fingerprint *f;
415
416			#define MATCH_INT(_MOD, _DC, _field) \
417			if ((f->fp_flags & _DC) == 0) { \
418			if ((f->fp_flags & _MOD) == 0) { \
419			if (f->_field != find->_field) \
420			continue; \
421			} else { \
422			if (f->_field == 0 \|\| find->_field % f->_field) \
423			continue; \
424			} \
425			}
426
427			SLIST_FOREACH(f, list, fp_next) {
428			if (f->fp_tcpopts != find->fp_tcpopts \|\|
429			f->fp_optcnt != find->fp_optcnt \|\|
430			f->fp_ttl < find->fp_ttl \|\|
431			f->fp_ttl - find->fp_ttl > ttldiff \|\|
432			(f->fp_flags & (PF_OSFP_DF\|PF_OSFP_TS0)) !=
433			(find->fp_flags & (PF_OSFP_DF\|PF_OSFP_TS0)))
434			continue;
435
436			MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
437			MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
438			MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
439			if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
440			if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
441			if (find->fp_mss == 0)
442			continue;
443
444			/* Some "smart" NAT devices and DSL routers will tweak the MSS size and
445			* will set it to whatever is suitable for the link type.
446			*/
447			#define SMART_MSS 1460
448			if ((find->fp_wsize % find->fp_mss \|\|
449			find->fp_wsize / find->fp_mss !=
450			f->fp_wsize) &&
451			(find->fp_wsize % SMART_MSS \|\|
452			find->fp_wsize / SMART_MSS !=
453			f->fp_wsize))
454			continue;
455			} else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
456			if (find->fp_mss == 0)
457			continue;
458
459			#define MTUOFF (sizeof(struct ip) + sizeof(struct tcphdr))
460			#define SMART_MTU (SMART_MSS + MTUOFF)
461			if ((find->fp_wsize % (find->fp_mss + MTUOFF) \|\|
462			find->fp_wsize / (find->fp_mss + MTUOFF) !=
463			f->fp_wsize) &&
464			(find->fp_wsize % SMART_MTU \|\|
465			find->fp_wsize / SMART_MTU !=
466			f->fp_wsize))
467			continue;
468			} else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
469			if (f->fp_wsize == 0 \|\| find->fp_wsize %
470			f->fp_wsize)
471			continue;
472			} else {
473			if (f->fp_wsize != find->fp_wsize)
474			continue;
475			}
476			}
477			return (f);
478			}
479
480			return (NULL);
481			}
482
483			/* Find an exact fingerprint in the list */
484			struct pf_os_fingerprint *
485			pf_osfp_find_exact(struct pf_osfp_list list, struct pf_os_fingerprint find)
486			{
487			struct pf_os_fingerprint *f;
488
489			SLIST_FOREACH(f, list, fp_next) {
490			if (f->fp_tcpopts == find->fp_tcpopts &&
491			f->fp_wsize == find->fp_wsize &&
492			f->fp_psize == find->fp_psize &&
493			f->fp_mss == find->fp_mss &&
494			f->fp_flags == find->fp_flags &&
495			f->fp_optcnt == find->fp_optcnt &&
496			f->fp_wscale == find->fp_wscale &&
497			f->fp_ttl == find->fp_ttl)
498			return (f);
499			}
500
501			return (NULL);
502			}
503
504			/* Insert a fingerprint into the list */
505			void
506			pf_osfp_insert(struct pf_osfp_list list, struct pf_os_fingerprint ins)
507			{
508			struct pf_os_fingerprint f, prev = NULL;
509
510			/* XXX need to go semi tree based. can key on tcp options */
511
512			SLIST_FOREACH(f, list, fp_next)
513			prev = f;
514			if (prev)
515			SLIST_INSERT_AFTER(prev, ins, fp_next);
516			else
517			SLIST_INSERT_HEAD(list, ins, fp_next);
518			}
519
520			/* Fill a fingerprint by its number (from an ioctl) */
521			int
522			pf_osfp_get(struct pf_osfp_ioctl *fpioc)
523			{
524			struct pf_os_fingerprint *fp;
525			struct pf_osfp_entry *entry;
526			int num = fpioc->fp_getnum;
527			int i = 0;
528
529
530			memset(fpioc, 0, sizeof(*fpioc));
531			SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
532			SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
533			if (i++ == num) {
534			fpioc->fp_mss = fp->fp_mss;
535			fpioc->fp_wsize = fp->fp_wsize;
536			fpioc->fp_flags = fp->fp_flags;
537			fpioc->fp_psize = fp->fp_psize;
538			fpioc->fp_ttl = fp->fp_ttl;
539			fpioc->fp_wscale = fp->fp_wscale;
540			fpioc->fp_getnum = num;
541			memcpy(&fpioc->fp_os, entry,
542			sizeof(fpioc->fp_os));
543			return (0);
544			}
545			}
546			}
547
548			return (EBUSY);
549			}
550
551
552			/* Validate that each signature is reachable */
553			struct pf_os_fingerprint *
554			pf_osfp_validate(void)
555			{
556			struct pf_os_fingerprint f, f2, find;
557
558			SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
559			memcpy(&find, f, sizeof(find));
560
561			/* We do a few MSS/th_win percolations to make things unique */
562			if (find.fp_mss == 0)
563			find.fp_mss = 128;
564			if (f->fp_flags & PF_OSFP_WSIZE_MSS)
565			find.fp_wsize *= find.fp_mss;
566			else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
567			find.fp_wsize *= (find.fp_mss + 40);
568			else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
569			find.fp_wsize *= 2;
570			if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
571			if (f2)
572			DPFPRINTF(LOG_NOTICE,
573			"Found \"%s %s %s\" instead of "
574			"\"%s %s %s\"\n",
575			SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
576			SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
577			SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
578			SLIST_FIRST(&f->fp_oses)->fp_class_nm,
579			SLIST_FIRST(&f->fp_oses)->fp_version_nm,
580			SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
581			else
582			DPFPRINTF(LOG_NOTICE,
583			"Couldn't find \"%s %s %s\"\n",
584			SLIST_FIRST(&f->fp_oses)->fp_class_nm,
585			SLIST_FIRST(&f->fp_oses)->fp_version_nm,
586			SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
587			return (f);
588			}
589			}
590			return (NULL);
591			}