1/* $OpenBSD: pf_osfp.c,v 1.14 2008/06/12 18:17:01 henning 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#ifdef __FreeBSD__
21#include <sys/cdefs.h>
22__FBSDID("$FreeBSD: head/sys/contrib/pf/net/pf_osfp.c 223637 2011-06-28 11:57:25Z bz $");
23#endif
24
25#include <sys/param.h>
26#include <sys/socket.h>
27#ifdef _KERNEL
28#include <sys/systm.h>
29#ifndef __FreeBSD__
30#include <sys/pool.h>
31#endif
32#endif /* _KERNEL */
33#include <sys/mbuf.h>
34
35#include <netinet/in.h>
36#include <netinet/in_systm.h>
37#include <netinet/ip.h>
38#include <netinet/tcp.h>
39
40#include <net/if.h>
41#include <net/pfvar.h>
42
43#include <netinet/ip6.h>
44#ifdef _KERNEL
45#include <netinet6/in6_var.h>
46#endif
47
48
49#ifdef _KERNEL
50#ifdef __FreeBSD__
51#define DPFPRINTF(format, x...) \
52 if (V_pf_status.debug >= PF_DEBUG_NOISY) \
53 printf(format , ##x)
54#else
55#define DPFPRINTF(format, x...) \
56 if (pf_status.debug >= PF_DEBUG_NOISY) \
57 printf(format , ##x)
58#endif
59#ifdef __FreeBSD__
60typedef uma_zone_t pool_t;
61#else
62typedef struct pool pool_t;
63#endif
64
65#else
66/* Userland equivalents so we can lend code to tcpdump et al. */
67
68#include <arpa/inet.h>
69#include <errno.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <netdb.h>
74#define pool_t int
75#define pool_get(pool, flags) malloc(*(pool))
76#define pool_put(pool, item) free(item)
77#define pool_init(pool, size, a, ao, f, m, p) (*(pool)) = (size)
78
79#ifdef __FreeBSD__
80#define NTOHS(x) (x) = ntohs((u_int16_t)(x))
81#endif
82
83#ifdef PFDEBUG
84#include <sys/stdarg.h>
85#define DPFPRINTF(format, x...) fprintf(stderr, format , ##x)
86#else
87#define DPFPRINTF(format, x...) ((void)0)
88#endif /* PFDEBUG */
89#endif /* _KERNEL */
90
91
92#ifdef __FreeBSD__
93SLIST_HEAD(pf_osfp_list, pf_os_fingerprint);
94VNET_DEFINE(struct pf_osfp_list, pf_osfp_list);
95#define V_pf_osfp_list VNET(pf_osfp_list)
96VNET_DEFINE(pool_t, pf_osfp_entry_pl);
97#define pf_osfp_entry_pl VNET(pf_osfp_entry_pl)
98VNET_DEFINE(pool_t, pf_osfp_pl);
99#define pf_osfp_pl VNET(pf_osfp_pl)
100#else
101SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
102pool_t pf_osfp_entry_pl;
103pool_t pf_osfp_pl;
104#endif
105
106struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *,
107 struct pf_os_fingerprint *, u_int8_t);
108struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *,
109 struct pf_os_fingerprint *);
110void pf_osfp_insert(struct pf_osfp_list *,
111 struct pf_os_fingerprint *);
112
113
114#ifdef _KERNEL
115/*
116 * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
117 * Returns the list of possible OSes.
118 */
119struct pf_osfp_enlist *
120pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
121 const struct tcphdr *tcp)
122{
123 struct ip *ip;
124 struct ip6_hdr *ip6;
125 char hdr[60];
126
127 if ((pd->af != PF_INET && pd->af != PF_INET6) ||
128 pd->proto != IPPROTO_TCP || (tcp->th_off << 2) < sizeof(*tcp))
129 return (NULL);
130
131 if (pd->af == PF_INET) {
132 ip = mtod(m, struct ip *);
133 ip6 = (struct ip6_hdr *)NULL;
134 } else {
135 ip = (struct ip *)NULL;
136 ip6 = mtod(m, struct ip6_hdr *);
137 }
138 if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
139 pd->af)) return (NULL);
140
141 return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
142}
143#endif /* _KERNEL */
144
145struct pf_osfp_enlist *
146pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6, const struct tcphdr *tcp)
147{
148 struct pf_os_fingerprint fp, *fpresult;
149 int cnt, optlen = 0;
150 const u_int8_t *optp;
151#ifdef _KERNEL
152 char srcname[128];
153#else
154 char srcname[NI_MAXHOST];
155#endif
156
157 if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
158 return (NULL);
159 if (ip) {
160 if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
161 return (NULL);
162 }
163
164 memset(&fp, 0, sizeof(fp));
165
166 if (ip) {
167#ifndef _KERNEL
168 struct sockaddr_in sin;
169#endif
170
171 fp.fp_psize = ntohs(ip->ip_len);
172 fp.fp_ttl = ip->ip_ttl;
173 if (ip->ip_off & htons(IP_DF))
174 fp.fp_flags |= PF_OSFP_DF;
175#ifdef _KERNEL
176 strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
177#else
178 memset(&sin, 0, sizeof(sin));
179 sin.sin_family = AF_INET;
180 sin.sin_len = sizeof(struct sockaddr_in);
181 sin.sin_addr = ip->ip_src;
182 (void)getnameinfo((struct sockaddr *)&sin,
183 sizeof(struct sockaddr_in), srcname, sizeof(srcname),
184 NULL, 0, NI_NUMERICHOST);
185#endif
186 }
187#ifdef INET6
188 else if (ip6) {
189#ifndef _KERNEL
190 struct sockaddr_in6 sin6;
191#endif
192
193 /* jumbo payload? */
194 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
195 fp.fp_ttl = ip6->ip6_hlim;
196 fp.fp_flags |= PF_OSFP_DF;
197 fp.fp_flags |= PF_OSFP_INET6;
198#ifdef _KERNEL
199 strlcpy(srcname, ip6_sprintf((struct in6_addr *)&ip6->ip6_src),
200 sizeof(srcname));
201#else
202 memset(&sin6, 0, sizeof(sin6));
203 sin6.sin6_family = AF_INET6;
204 sin6.sin6_len = sizeof(struct sockaddr_in6);
205 sin6.sin6_addr = ip6->ip6_src;
206 (void)getnameinfo((struct sockaddr *)&sin6,
207 sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
208 NULL, 0, NI_NUMERICHOST);
209#endif
210 }
211#endif
212 else
213 return (NULL);
214 fp.fp_wsize = ntohs(tcp->th_win);
215
216
217 cnt = (tcp->th_off << 2) - sizeof(*tcp);
218 optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
219 for (; cnt > 0; cnt -= optlen, optp += optlen) {
220 if (*optp == TCPOPT_EOL)
221 break;
222
223 fp.fp_optcnt++;
224 if (*optp == TCPOPT_NOP) {
225 fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
226 PF_OSFP_TCPOPT_NOP;
227 optlen = 1;
228 } else {
229 if (cnt < 2)
230 return (NULL);
231 optlen = optp[1];
232 if (optlen > cnt || optlen < 2)
233 return (NULL);
234 switch (*optp) {
235 case TCPOPT_MAXSEG:
236 if (optlen >= TCPOLEN_MAXSEG)
237 memcpy(&fp.fp_mss, &optp[2],
238 sizeof(fp.fp_mss));
239 fp.fp_tcpopts = (fp.fp_tcpopts <<
240 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
241 NTOHS(fp.fp_mss);
242 break;
243 case TCPOPT_WINDOW:
244 if (optlen >= TCPOLEN_WINDOW)
245 memcpy(&fp.fp_wscale, &optp[2],
246 sizeof(fp.fp_wscale));
247 NTOHS(fp.fp_wscale);
248 fp.fp_tcpopts = (fp.fp_tcpopts <<
249 PF_OSFP_TCPOPT_BITS) |
250 PF_OSFP_TCPOPT_WSCALE;
251 break;
252 case TCPOPT_SACK_PERMITTED:
253 fp.fp_tcpopts = (fp.fp_tcpopts <<
254 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
255 break;
256 case TCPOPT_TIMESTAMP:
257 if (optlen >= TCPOLEN_TIMESTAMP) {
258 u_int32_t ts;
259 memcpy(&ts, &optp[2], sizeof(ts));
260 if (ts == 0)
261 fp.fp_flags |= PF_OSFP_TS0;
262
263 }
264 fp.fp_tcpopts = (fp.fp_tcpopts <<
265 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
266 break;
267 default:
268 return (NULL);
269 }
270 }
271 optlen = MAX(optlen, 1); /* paranoia */
272 }
273
274 DPFPRINTF("fingerprinted %s:%d %d:%d:%d:%d:%llx (%d) "
275 "(TS=%s,M=%s%d,W=%s%d)\n",
276 srcname, ntohs(tcp->th_sport),
277 fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
278 fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
279 (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
280 (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
281 (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
282 fp.fp_mss,
283 (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
284 (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
285 fp.fp_wscale);
286
287#ifdef __FreeBSD__
288 if ((fpresult = pf_osfp_find(&V_pf_osfp_list, &fp,
289#else
290 if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
291#endif
292 PF_OSFP_MAXTTL_OFFSET)))
293 return (&fpresult->fp_oses);
294 return (NULL);
295}
296
297/* Match a fingerprint ID against a list of OSes */
298int
299pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
300{
301 struct pf_osfp_entry *entry;
302 int os_class, os_version, os_subtype;
303 int en_class, en_version, en_subtype;
304
305 if (os == PF_OSFP_ANY)
306 return (1);
307 if (list == NULL) {
308 DPFPRINTF("osfp no match against %x\n", os);
309 return (os == PF_OSFP_UNKNOWN);
310 }
311 PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
312 SLIST_FOREACH(entry, list, fp_entry) {
313 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
314 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
315 (os_version == PF_OSFP_ANY || en_version == os_version) &&
316 (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
317 DPFPRINTF("osfp matched %s %s %s %x==%x\n",
318 entry->fp_class_nm, entry->fp_version_nm,
319 entry->fp_subtype_nm, os, entry->fp_os);
320 return (1);
321 }
322 }
323 DPFPRINTF("fingerprint 0x%x didn't match\n", os);
324 return (0);
325}
326
327/* Initialize the OS fingerprint system */
328#ifdef __FreeBSD__
329int
330#else
331void
332#endif
333pf_osfp_initialize(void)
334{
335#if defined(__FreeBSD__) && defined(_KERNEL)
336 int error = ENOMEM;
337
338 do {
339 pf_osfp_entry_pl = pf_osfp_pl = NULL;
340 UMA_CREATE(pf_osfp_entry_pl, struct pf_osfp_entry, "pfospfen");
341 UMA_CREATE(pf_osfp_pl, struct pf_os_fingerprint, "pfosfp");
342 error = 0;
343 } while(0);
344
345 SLIST_INIT(&V_pf_osfp_list);
346#else
347 pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
348 "pfosfpen", &pool_allocator_nointr);
349 pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
350 "pfosfp", &pool_allocator_nointr);
351 SLIST_INIT(&pf_osfp_list);
352#endif
353
354#ifdef __FreeBSD__
355#ifdef _KERNEL
356 return (error);
357#else
358 return (0);
359#endif
360#endif
361}
362
363#if defined(__FreeBSD__) && (_KERNEL)
364void
365pf_osfp_cleanup(void)
366{
367
368 UMA_DESTROY(pf_osfp_entry_pl);
369 UMA_DESTROY(pf_osfp_pl);
370}
371#endif
372
373/* Flush the fingerprint list */
374void
375pf_osfp_flush(void)
376{
377 struct pf_os_fingerprint *fp;
378 struct pf_osfp_entry *entry;
379
380#ifdef __FreeBSD__
381 while ((fp = SLIST_FIRST(&V_pf_osfp_list))) {
382 SLIST_REMOVE_HEAD(&V_pf_osfp_list, fp_next);
383#else
384 while ((fp = SLIST_FIRST(&pf_osfp_list))) {
385 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
386#endif
387 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
388 SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
389 pool_put(&pf_osfp_entry_pl, entry);
390 }
391 pool_put(&pf_osfp_pl, fp);
392 }
393}
394
395
396/* Add a fingerprint */
397int
398pf_osfp_add(struct pf_osfp_ioctl *fpioc)
399{
400 struct pf_os_fingerprint *fp, fpadd;
401 struct pf_osfp_entry *entry;
402
403 memset(&fpadd, 0, sizeof(fpadd));
404 fpadd.fp_tcpopts = fpioc->fp_tcpopts;
405 fpadd.fp_wsize = fpioc->fp_wsize;
406 fpadd.fp_psize = fpioc->fp_psize;
407 fpadd.fp_mss = fpioc->fp_mss;
408 fpadd.fp_flags = fpioc->fp_flags;
409 fpadd.fp_optcnt = fpioc->fp_optcnt;
410 fpadd.fp_wscale = fpioc->fp_wscale;
411 fpadd.fp_ttl = fpioc->fp_ttl;
412
413#if 0 /* XXX RYAN wants to fix logging */
414 DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
415 "(TS=%s,M=%s%d,W=%s%d) %x\n",
416 fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
417 fpioc->fp_os.fp_subtype_nm,
418 (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
419 (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
420 (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
421 (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
422 fpadd.fp_wsize,
423 fpadd.fp_ttl,
424 (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
425 (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
426 (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
427 fpadd.fp_psize,
428 (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
429 (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
430 (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
431 (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
432 fpadd.fp_mss,
433 (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
434 (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
435 fpadd.fp_wscale,
436 fpioc->fp_os.fp_os);
437#endif
438
439#ifdef __FreeBSD__
440 if ((fp = pf_osfp_find_exact(&V_pf_osfp_list, &fpadd))) {
441#else
442 if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
443#endif
444 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
445 if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
446 return (EEXIST);
447 }
448 if ((entry = pool_get(&pf_osfp_entry_pl,
449#ifdef __FreeBSD__
450 PR_NOWAIT)) == NULL)
451#else
452 PR_WAITOK|PR_LIMITFAIL)) == NULL)
453#endif
454 return (ENOMEM);
455 } else {
456 if ((fp = pool_get(&pf_osfp_pl,
457#ifdef __FreeBSD__
458 PR_NOWAIT)) == NULL)
459#else
460 PR_WAITOK|PR_LIMITFAIL)) == NULL)
461#endif
462 return (ENOMEM);
463 memset(fp, 0, sizeof(*fp));
464 fp->fp_tcpopts = fpioc->fp_tcpopts;
465 fp->fp_wsize = fpioc->fp_wsize;
466 fp->fp_psize = fpioc->fp_psize;
467 fp->fp_mss = fpioc->fp_mss;
468 fp->fp_flags = fpioc->fp_flags;
469 fp->fp_optcnt = fpioc->fp_optcnt;
470 fp->fp_wscale = fpioc->fp_wscale;
471 fp->fp_ttl = fpioc->fp_ttl;
472 SLIST_INIT(&fp->fp_oses);
473 if ((entry = pool_get(&pf_osfp_entry_pl,
474#ifdef __FreeBSD__
475 PR_NOWAIT)) == NULL) {
476#else
477 PR_WAITOK|PR_LIMITFAIL)) == NULL) {
478#endif
479 pool_put(&pf_osfp_pl, fp);
480 return (ENOMEM);
481 }
482#ifdef __FreeBSD__
483 pf_osfp_insert(&V_pf_osfp_list, fp);
484#else
485 pf_osfp_insert(&pf_osfp_list, fp);
486#endif
487 }
488 memcpy(entry, &fpioc->fp_os, sizeof(*entry));
489
490 /* Make sure the strings are NUL terminated */
491 entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
492 entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
493 entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
494
495 SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
496
497#ifdef PFDEBUG
498 if ((fp = pf_osfp_validate()))
499 printf("Invalid fingerprint list\n");
500#endif /* PFDEBUG */
501 return (0);
502}
503
504
505/* Find a fingerprint in the list */
506struct pf_os_fingerprint *
507pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
508 u_int8_t ttldiff)
509{
510 struct pf_os_fingerprint *f;
511
512#define MATCH_INT(_MOD, _DC, _field) \
513 if ((f->fp_flags & _DC) == 0) { \
514 if ((f->fp_flags & _MOD) == 0) { \
515 if (f->_field != find->_field) \
516 continue; \
517 } else { \
518 if (f->_field == 0 || find->_field % f->_field) \
519 continue; \
520 } \
521 }
522
523 SLIST_FOREACH(f, list, fp_next) {
524 if (f->fp_tcpopts != find->fp_tcpopts ||
525 f->fp_optcnt != find->fp_optcnt ||
526 f->fp_ttl < find->fp_ttl ||
527 f->fp_ttl - find->fp_ttl > ttldiff ||
528 (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
529 (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
530 continue;
531
532 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
533 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
534 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
535 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
536 if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
537 if (find->fp_mss == 0)
538 continue;
539
540/*
541 * Some "smart" NAT devices and DSL routers will tweak the MSS size and
542 * will set it to whatever is suitable for the link type.
543 */
544#define SMART_MSS 1460
545 if ((find->fp_wsize % find->fp_mss ||
546 find->fp_wsize / find->fp_mss !=
547 f->fp_wsize) &&
548 (find->fp_wsize % SMART_MSS ||
549 find->fp_wsize / SMART_MSS !=
550 f->fp_wsize))
551 continue;
552 } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
553 if (find->fp_mss == 0)
554 continue;
555
556#define MTUOFF (sizeof(struct ip) + sizeof(struct tcphdr))
557#define SMART_MTU (SMART_MSS + MTUOFF)
558 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
559 find->fp_wsize / (find->fp_mss + MTUOFF) !=
560 f->fp_wsize) &&
561 (find->fp_wsize % SMART_MTU ||
562 find->fp_wsize / SMART_MTU !=
563 f->fp_wsize))
564 continue;
565 } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
566 if (f->fp_wsize == 0 || find->fp_wsize %
567 f->fp_wsize)
568 continue;
569 } else {
570 if (f->fp_wsize != find->fp_wsize)
571 continue;
572 }
573 }
574 return (f);
575 }
576
577 return (NULL);
578}
579
580/* Find an exact fingerprint in the list */
581struct pf_os_fingerprint *
582pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
583{
584 struct pf_os_fingerprint *f;
585
586 SLIST_FOREACH(f, list, fp_next) {
587 if (f->fp_tcpopts == find->fp_tcpopts &&
588 f->fp_wsize == find->fp_wsize &&
589 f->fp_psize == find->fp_psize &&
590 f->fp_mss == find->fp_mss &&
591 f->fp_flags == find->fp_flags &&
592 f->fp_optcnt == find->fp_optcnt &&
593 f->fp_wscale == find->fp_wscale &&
594 f->fp_ttl == find->fp_ttl)
595 return (f);
596 }
597
598 return (NULL);
599}
600
601/* Insert a fingerprint into the list */
602void
603pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
604{
605 struct pf_os_fingerprint *f, *prev = NULL;
606
607 /* XXX need to go semi tree based. can key on tcp options */
608
609 SLIST_FOREACH(f, list, fp_next)
610 prev = f;
611 if (prev)
612 SLIST_INSERT_AFTER(prev, ins, fp_next);
613 else
614 SLIST_INSERT_HEAD(list, ins, fp_next);
615}
616
617/* Fill a fingerprint by its number (from an ioctl) */
618int
619pf_osfp_get(struct pf_osfp_ioctl *fpioc)
620{
621 struct pf_os_fingerprint *fp;
622 struct pf_osfp_entry *entry;
623 int num = fpioc->fp_getnum;
624 int i = 0;
625
626
627 memset(fpioc, 0, sizeof(*fpioc));
628#ifdef __FreeBSD__
629 SLIST_FOREACH(fp, &V_pf_osfp_list, fp_next) {
630#else
631 SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
632#endif
633 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
634 if (i++ == num) {
635 fpioc->fp_mss = fp->fp_mss;
636 fpioc->fp_wsize = fp->fp_wsize;
637 fpioc->fp_flags = fp->fp_flags;
638 fpioc->fp_psize = fp->fp_psize;
639 fpioc->fp_ttl = fp->fp_ttl;
640 fpioc->fp_wscale = fp->fp_wscale;
641 fpioc->fp_getnum = num;
642 memcpy(&fpioc->fp_os, entry,
643 sizeof(fpioc->fp_os));
644 return (0);
645 }
646 }
647 }
648
649 return (EBUSY);
650}
651
652
653/* Validate that each signature is reachable */
654struct pf_os_fingerprint *
655pf_osfp_validate(void)
656{
657 struct pf_os_fingerprint *f, *f2, find;
658
659#ifdef __FreeBSD__
660 SLIST_FOREACH(f, &V_pf_osfp_list, fp_next) {
661#else
662 SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
663#endif
664 memcpy(&find, f, sizeof(find));
665
666 /* We do a few MSS/th_win percolations to make things unique */
667 if (find.fp_mss == 0)
668 find.fp_mss = 128;
669 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
670 find.fp_wsize *= find.fp_mss;
671 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
672 find.fp_wsize *= (find.fp_mss + 40);
673 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
674 find.fp_wsize *= 2;
675#ifdef __FreeBSD__
676 if (f != (f2 = pf_osfp_find(&V_pf_osfp_list, &find, 0))) {
677#else
678 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
679#endif
680 if (f2)
681 printf("Found \"%s %s %s\" instead of "
682 "\"%s %s %s\"\n",
683 SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
684 SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
685 SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
686 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
687 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
688 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
689 else
690 printf("Couldn't find \"%s %s %s\"\n",
691 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
692 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
693 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
694 return (f);
695 }
696 }
697 return (NULL);
698}
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#ifdef __FreeBSD__
21#include <sys/cdefs.h>
22__FBSDID("$FreeBSD: head/sys/contrib/pf/net/pf_osfp.c 223637 2011-06-28 11:57:25Z bz $");
23#endif
24
25#include <sys/param.h>
26#include <sys/socket.h>
27#ifdef _KERNEL
28#include <sys/systm.h>
29#ifndef __FreeBSD__
30#include <sys/pool.h>
31#endif
32#endif /* _KERNEL */
33#include <sys/mbuf.h>
34
35#include <netinet/in.h>
36#include <netinet/in_systm.h>
37#include <netinet/ip.h>
38#include <netinet/tcp.h>
39
40#include <net/if.h>
41#include <net/pfvar.h>
42
43#include <netinet/ip6.h>
44#ifdef _KERNEL
45#include <netinet6/in6_var.h>
46#endif
47
48
49#ifdef _KERNEL
50#ifdef __FreeBSD__
51#define DPFPRINTF(format, x...) \
52 if (V_pf_status.debug >= PF_DEBUG_NOISY) \
53 printf(format , ##x)
54#else
55#define DPFPRINTF(format, x...) \
56 if (pf_status.debug >= PF_DEBUG_NOISY) \
57 printf(format , ##x)
58#endif
59#ifdef __FreeBSD__
60typedef uma_zone_t pool_t;
61#else
62typedef struct pool pool_t;
63#endif
64
65#else
66/* Userland equivalents so we can lend code to tcpdump et al. */
67
68#include <arpa/inet.h>
69#include <errno.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <netdb.h>
74#define pool_t int
75#define pool_get(pool, flags) malloc(*(pool))
76#define pool_put(pool, item) free(item)
77#define pool_init(pool, size, a, ao, f, m, p) (*(pool)) = (size)
78
79#ifdef __FreeBSD__
80#define NTOHS(x) (x) = ntohs((u_int16_t)(x))
81#endif
82
83#ifdef PFDEBUG
84#include <sys/stdarg.h>
85#define DPFPRINTF(format, x...) fprintf(stderr, format , ##x)
86#else
87#define DPFPRINTF(format, x...) ((void)0)
88#endif /* PFDEBUG */
89#endif /* _KERNEL */
90
91
92#ifdef __FreeBSD__
93SLIST_HEAD(pf_osfp_list, pf_os_fingerprint);
94VNET_DEFINE(struct pf_osfp_list, pf_osfp_list);
95#define V_pf_osfp_list VNET(pf_osfp_list)
96VNET_DEFINE(pool_t, pf_osfp_entry_pl);
97#define pf_osfp_entry_pl VNET(pf_osfp_entry_pl)
98VNET_DEFINE(pool_t, pf_osfp_pl);
99#define pf_osfp_pl VNET(pf_osfp_pl)
100#else
101SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
102pool_t pf_osfp_entry_pl;
103pool_t pf_osfp_pl;
104#endif
105
106struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *,
107 struct pf_os_fingerprint *, u_int8_t);
108struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *,
109 struct pf_os_fingerprint *);
110void pf_osfp_insert(struct pf_osfp_list *,
111 struct pf_os_fingerprint *);
112
113
114#ifdef _KERNEL
115/*
116 * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
117 * Returns the list of possible OSes.
118 */
119struct pf_osfp_enlist *
120pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
121 const struct tcphdr *tcp)
122{
123 struct ip *ip;
124 struct ip6_hdr *ip6;
125 char hdr[60];
126
127 if ((pd->af != PF_INET && pd->af != PF_INET6) ||
128 pd->proto != IPPROTO_TCP || (tcp->th_off << 2) < sizeof(*tcp))
129 return (NULL);
130
131 if (pd->af == PF_INET) {
132 ip = mtod(m, struct ip *);
133 ip6 = (struct ip6_hdr *)NULL;
134 } else {
135 ip = (struct ip *)NULL;
136 ip6 = mtod(m, struct ip6_hdr *);
137 }
138 if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
139 pd->af)) return (NULL);
140
141 return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
142}
143#endif /* _KERNEL */
144
145struct pf_osfp_enlist *
146pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6, const struct tcphdr *tcp)
147{
148 struct pf_os_fingerprint fp, *fpresult;
149 int cnt, optlen = 0;
150 const u_int8_t *optp;
151#ifdef _KERNEL
152 char srcname[128];
153#else
154 char srcname[NI_MAXHOST];
155#endif
156
157 if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
158 return (NULL);
159 if (ip) {
160 if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
161 return (NULL);
162 }
163
164 memset(&fp, 0, sizeof(fp));
165
166 if (ip) {
167#ifndef _KERNEL
168 struct sockaddr_in sin;
169#endif
170
171 fp.fp_psize = ntohs(ip->ip_len);
172 fp.fp_ttl = ip->ip_ttl;
173 if (ip->ip_off & htons(IP_DF))
174 fp.fp_flags |= PF_OSFP_DF;
175#ifdef _KERNEL
176 strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
177#else
178 memset(&sin, 0, sizeof(sin));
179 sin.sin_family = AF_INET;
180 sin.sin_len = sizeof(struct sockaddr_in);
181 sin.sin_addr = ip->ip_src;
182 (void)getnameinfo((struct sockaddr *)&sin,
183 sizeof(struct sockaddr_in), srcname, sizeof(srcname),
184 NULL, 0, NI_NUMERICHOST);
185#endif
186 }
187#ifdef INET6
188 else if (ip6) {
189#ifndef _KERNEL
190 struct sockaddr_in6 sin6;
191#endif
192
193 /* jumbo payload? */
194 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
195 fp.fp_ttl = ip6->ip6_hlim;
196 fp.fp_flags |= PF_OSFP_DF;
197 fp.fp_flags |= PF_OSFP_INET6;
198#ifdef _KERNEL
199 strlcpy(srcname, ip6_sprintf((struct in6_addr *)&ip6->ip6_src),
200 sizeof(srcname));
201#else
202 memset(&sin6, 0, sizeof(sin6));
203 sin6.sin6_family = AF_INET6;
204 sin6.sin6_len = sizeof(struct sockaddr_in6);
205 sin6.sin6_addr = ip6->ip6_src;
206 (void)getnameinfo((struct sockaddr *)&sin6,
207 sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
208 NULL, 0, NI_NUMERICHOST);
209#endif
210 }
211#endif
212 else
213 return (NULL);
214 fp.fp_wsize = ntohs(tcp->th_win);
215
216
217 cnt = (tcp->th_off << 2) - sizeof(*tcp);
218 optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
219 for (; cnt > 0; cnt -= optlen, optp += optlen) {
220 if (*optp == TCPOPT_EOL)
221 break;
222
223 fp.fp_optcnt++;
224 if (*optp == TCPOPT_NOP) {
225 fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
226 PF_OSFP_TCPOPT_NOP;
227 optlen = 1;
228 } else {
229 if (cnt < 2)
230 return (NULL);
231 optlen = optp[1];
232 if (optlen > cnt || optlen < 2)
233 return (NULL);
234 switch (*optp) {
235 case TCPOPT_MAXSEG:
236 if (optlen >= TCPOLEN_MAXSEG)
237 memcpy(&fp.fp_mss, &optp[2],
238 sizeof(fp.fp_mss));
239 fp.fp_tcpopts = (fp.fp_tcpopts <<
240 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
241 NTOHS(fp.fp_mss);
242 break;
243 case TCPOPT_WINDOW:
244 if (optlen >= TCPOLEN_WINDOW)
245 memcpy(&fp.fp_wscale, &optp[2],
246 sizeof(fp.fp_wscale));
247 NTOHS(fp.fp_wscale);
248 fp.fp_tcpopts = (fp.fp_tcpopts <<
249 PF_OSFP_TCPOPT_BITS) |
250 PF_OSFP_TCPOPT_WSCALE;
251 break;
252 case TCPOPT_SACK_PERMITTED:
253 fp.fp_tcpopts = (fp.fp_tcpopts <<
254 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
255 break;
256 case TCPOPT_TIMESTAMP:
257 if (optlen >= TCPOLEN_TIMESTAMP) {
258 u_int32_t ts;
259 memcpy(&ts, &optp[2], sizeof(ts));
260 if (ts == 0)
261 fp.fp_flags |= PF_OSFP_TS0;
262
263 }
264 fp.fp_tcpopts = (fp.fp_tcpopts <<
265 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
266 break;
267 default:
268 return (NULL);
269 }
270 }
271 optlen = MAX(optlen, 1); /* paranoia */
272 }
273
274 DPFPRINTF("fingerprinted %s:%d %d:%d:%d:%d:%llx (%d) "
275 "(TS=%s,M=%s%d,W=%s%d)\n",
276 srcname, ntohs(tcp->th_sport),
277 fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
278 fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
279 (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
280 (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
281 (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
282 fp.fp_mss,
283 (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
284 (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
285 fp.fp_wscale);
286
287#ifdef __FreeBSD__
288 if ((fpresult = pf_osfp_find(&V_pf_osfp_list, &fp,
289#else
290 if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
291#endif
292 PF_OSFP_MAXTTL_OFFSET)))
293 return (&fpresult->fp_oses);
294 return (NULL);
295}
296
297/* Match a fingerprint ID against a list of OSes */
298int
299pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
300{
301 struct pf_osfp_entry *entry;
302 int os_class, os_version, os_subtype;
303 int en_class, en_version, en_subtype;
304
305 if (os == PF_OSFP_ANY)
306 return (1);
307 if (list == NULL) {
308 DPFPRINTF("osfp no match against %x\n", os);
309 return (os == PF_OSFP_UNKNOWN);
310 }
311 PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
312 SLIST_FOREACH(entry, list, fp_entry) {
313 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
314 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
315 (os_version == PF_OSFP_ANY || en_version == os_version) &&
316 (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
317 DPFPRINTF("osfp matched %s %s %s %x==%x\n",
318 entry->fp_class_nm, entry->fp_version_nm,
319 entry->fp_subtype_nm, os, entry->fp_os);
320 return (1);
321 }
322 }
323 DPFPRINTF("fingerprint 0x%x didn't match\n", os);
324 return (0);
325}
326
327/* Initialize the OS fingerprint system */
328#ifdef __FreeBSD__
329int
330#else
331void
332#endif
333pf_osfp_initialize(void)
334{
335#if defined(__FreeBSD__) && defined(_KERNEL)
336 int error = ENOMEM;
337
338 do {
339 pf_osfp_entry_pl = pf_osfp_pl = NULL;
340 UMA_CREATE(pf_osfp_entry_pl, struct pf_osfp_entry, "pfospfen");
341 UMA_CREATE(pf_osfp_pl, struct pf_os_fingerprint, "pfosfp");
342 error = 0;
343 } while(0);
344
345 SLIST_INIT(&V_pf_osfp_list);
346#else
347 pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
348 "pfosfpen", &pool_allocator_nointr);
349 pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
350 "pfosfp", &pool_allocator_nointr);
351 SLIST_INIT(&pf_osfp_list);
352#endif
353
354#ifdef __FreeBSD__
355#ifdef _KERNEL
356 return (error);
357#else
358 return (0);
359#endif
360#endif
361}
362
363#if defined(__FreeBSD__) && (_KERNEL)
364void
365pf_osfp_cleanup(void)
366{
367
368 UMA_DESTROY(pf_osfp_entry_pl);
369 UMA_DESTROY(pf_osfp_pl);
370}
371#endif
372
373/* Flush the fingerprint list */
374void
375pf_osfp_flush(void)
376{
377 struct pf_os_fingerprint *fp;
378 struct pf_osfp_entry *entry;
379
380#ifdef __FreeBSD__
381 while ((fp = SLIST_FIRST(&V_pf_osfp_list))) {
382 SLIST_REMOVE_HEAD(&V_pf_osfp_list, fp_next);
383#else
384 while ((fp = SLIST_FIRST(&pf_osfp_list))) {
385 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
386#endif
387 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
388 SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
389 pool_put(&pf_osfp_entry_pl, entry);
390 }
391 pool_put(&pf_osfp_pl, fp);
392 }
393}
394
395
396/* Add a fingerprint */
397int
398pf_osfp_add(struct pf_osfp_ioctl *fpioc)
399{
400 struct pf_os_fingerprint *fp, fpadd;
401 struct pf_osfp_entry *entry;
402
403 memset(&fpadd, 0, sizeof(fpadd));
404 fpadd.fp_tcpopts = fpioc->fp_tcpopts;
405 fpadd.fp_wsize = fpioc->fp_wsize;
406 fpadd.fp_psize = fpioc->fp_psize;
407 fpadd.fp_mss = fpioc->fp_mss;
408 fpadd.fp_flags = fpioc->fp_flags;
409 fpadd.fp_optcnt = fpioc->fp_optcnt;
410 fpadd.fp_wscale = fpioc->fp_wscale;
411 fpadd.fp_ttl = fpioc->fp_ttl;
412
413#if 0 /* XXX RYAN wants to fix logging */
414 DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
415 "(TS=%s,M=%s%d,W=%s%d) %x\n",
416 fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
417 fpioc->fp_os.fp_subtype_nm,
418 (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
419 (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
420 (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
421 (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
422 fpadd.fp_wsize,
423 fpadd.fp_ttl,
424 (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
425 (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
426 (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
427 fpadd.fp_psize,
428 (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
429 (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
430 (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
431 (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
432 fpadd.fp_mss,
433 (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
434 (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
435 fpadd.fp_wscale,
436 fpioc->fp_os.fp_os);
437#endif
438
439#ifdef __FreeBSD__
440 if ((fp = pf_osfp_find_exact(&V_pf_osfp_list, &fpadd))) {
441#else
442 if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
443#endif
444 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
445 if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
446 return (EEXIST);
447 }
448 if ((entry = pool_get(&pf_osfp_entry_pl,
449#ifdef __FreeBSD__
450 PR_NOWAIT)) == NULL)
451#else
452 PR_WAITOK|PR_LIMITFAIL)) == NULL)
453#endif
454 return (ENOMEM);
455 } else {
456 if ((fp = pool_get(&pf_osfp_pl,
457#ifdef __FreeBSD__
458 PR_NOWAIT)) == NULL)
459#else
460 PR_WAITOK|PR_LIMITFAIL)) == NULL)
461#endif
462 return (ENOMEM);
463 memset(fp, 0, sizeof(*fp));
464 fp->fp_tcpopts = fpioc->fp_tcpopts;
465 fp->fp_wsize = fpioc->fp_wsize;
466 fp->fp_psize = fpioc->fp_psize;
467 fp->fp_mss = fpioc->fp_mss;
468 fp->fp_flags = fpioc->fp_flags;
469 fp->fp_optcnt = fpioc->fp_optcnt;
470 fp->fp_wscale = fpioc->fp_wscale;
471 fp->fp_ttl = fpioc->fp_ttl;
472 SLIST_INIT(&fp->fp_oses);
473 if ((entry = pool_get(&pf_osfp_entry_pl,
474#ifdef __FreeBSD__
475 PR_NOWAIT)) == NULL) {
476#else
477 PR_WAITOK|PR_LIMITFAIL)) == NULL) {
478#endif
479 pool_put(&pf_osfp_pl, fp);
480 return (ENOMEM);
481 }
482#ifdef __FreeBSD__
483 pf_osfp_insert(&V_pf_osfp_list, fp);
484#else
485 pf_osfp_insert(&pf_osfp_list, fp);
486#endif
487 }
488 memcpy(entry, &fpioc->fp_os, sizeof(*entry));
489
490 /* Make sure the strings are NUL terminated */
491 entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
492 entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
493 entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
494
495 SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
496
497#ifdef PFDEBUG
498 if ((fp = pf_osfp_validate()))
499 printf("Invalid fingerprint list\n");
500#endif /* PFDEBUG */
501 return (0);
502}
503
504
505/* Find a fingerprint in the list */
506struct pf_os_fingerprint *
507pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
508 u_int8_t ttldiff)
509{
510 struct pf_os_fingerprint *f;
511
512#define MATCH_INT(_MOD, _DC, _field) \
513 if ((f->fp_flags & _DC) == 0) { \
514 if ((f->fp_flags & _MOD) == 0) { \
515 if (f->_field != find->_field) \
516 continue; \
517 } else { \
518 if (f->_field == 0 || find->_field % f->_field) \
519 continue; \
520 } \
521 }
522
523 SLIST_FOREACH(f, list, fp_next) {
524 if (f->fp_tcpopts != find->fp_tcpopts ||
525 f->fp_optcnt != find->fp_optcnt ||
526 f->fp_ttl < find->fp_ttl ||
527 f->fp_ttl - find->fp_ttl > ttldiff ||
528 (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
529 (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
530 continue;
531
532 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
533 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
534 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
535 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
536 if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
537 if (find->fp_mss == 0)
538 continue;
539
540/*
541 * Some "smart" NAT devices and DSL routers will tweak the MSS size and
542 * will set it to whatever is suitable for the link type.
543 */
544#define SMART_MSS 1460
545 if ((find->fp_wsize % find->fp_mss ||
546 find->fp_wsize / find->fp_mss !=
547 f->fp_wsize) &&
548 (find->fp_wsize % SMART_MSS ||
549 find->fp_wsize / SMART_MSS !=
550 f->fp_wsize))
551 continue;
552 } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
553 if (find->fp_mss == 0)
554 continue;
555
556#define MTUOFF (sizeof(struct ip) + sizeof(struct tcphdr))
557#define SMART_MTU (SMART_MSS + MTUOFF)
558 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
559 find->fp_wsize / (find->fp_mss + MTUOFF) !=
560 f->fp_wsize) &&
561 (find->fp_wsize % SMART_MTU ||
562 find->fp_wsize / SMART_MTU !=
563 f->fp_wsize))
564 continue;
565 } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
566 if (f->fp_wsize == 0 || find->fp_wsize %
567 f->fp_wsize)
568 continue;
569 } else {
570 if (f->fp_wsize != find->fp_wsize)
571 continue;
572 }
573 }
574 return (f);
575 }
576
577 return (NULL);
578}
579
580/* Find an exact fingerprint in the list */
581struct pf_os_fingerprint *
582pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
583{
584 struct pf_os_fingerprint *f;
585
586 SLIST_FOREACH(f, list, fp_next) {
587 if (f->fp_tcpopts == find->fp_tcpopts &&
588 f->fp_wsize == find->fp_wsize &&
589 f->fp_psize == find->fp_psize &&
590 f->fp_mss == find->fp_mss &&
591 f->fp_flags == find->fp_flags &&
592 f->fp_optcnt == find->fp_optcnt &&
593 f->fp_wscale == find->fp_wscale &&
594 f->fp_ttl == find->fp_ttl)
595 return (f);
596 }
597
598 return (NULL);
599}
600
601/* Insert a fingerprint into the list */
602void
603pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
604{
605 struct pf_os_fingerprint *f, *prev = NULL;
606
607 /* XXX need to go semi tree based. can key on tcp options */
608
609 SLIST_FOREACH(f, list, fp_next)
610 prev = f;
611 if (prev)
612 SLIST_INSERT_AFTER(prev, ins, fp_next);
613 else
614 SLIST_INSERT_HEAD(list, ins, fp_next);
615}
616
617/* Fill a fingerprint by its number (from an ioctl) */
618int
619pf_osfp_get(struct pf_osfp_ioctl *fpioc)
620{
621 struct pf_os_fingerprint *fp;
622 struct pf_osfp_entry *entry;
623 int num = fpioc->fp_getnum;
624 int i = 0;
625
626
627 memset(fpioc, 0, sizeof(*fpioc));
628#ifdef __FreeBSD__
629 SLIST_FOREACH(fp, &V_pf_osfp_list, fp_next) {
630#else
631 SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
632#endif
633 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
634 if (i++ == num) {
635 fpioc->fp_mss = fp->fp_mss;
636 fpioc->fp_wsize = fp->fp_wsize;
637 fpioc->fp_flags = fp->fp_flags;
638 fpioc->fp_psize = fp->fp_psize;
639 fpioc->fp_ttl = fp->fp_ttl;
640 fpioc->fp_wscale = fp->fp_wscale;
641 fpioc->fp_getnum = num;
642 memcpy(&fpioc->fp_os, entry,
643 sizeof(fpioc->fp_os));
644 return (0);
645 }
646 }
647 }
648
649 return (EBUSY);
650}
651
652
653/* Validate that each signature is reachable */
654struct pf_os_fingerprint *
655pf_osfp_validate(void)
656{
657 struct pf_os_fingerprint *f, *f2, find;
658
659#ifdef __FreeBSD__
660 SLIST_FOREACH(f, &V_pf_osfp_list, fp_next) {
661#else
662 SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
663#endif
664 memcpy(&find, f, sizeof(find));
665
666 /* We do a few MSS/th_win percolations to make things unique */
667 if (find.fp_mss == 0)
668 find.fp_mss = 128;
669 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
670 find.fp_wsize *= find.fp_mss;
671 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
672 find.fp_wsize *= (find.fp_mss + 40);
673 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
674 find.fp_wsize *= 2;
675#ifdef __FreeBSD__
676 if (f != (f2 = pf_osfp_find(&V_pf_osfp_list, &find, 0))) {
677#else
678 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
679#endif
680 if (f2)
681 printf("Found \"%s %s %s\" instead of "
682 "\"%s %s %s\"\n",
683 SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
684 SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
685 SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
686 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
687 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
688 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
689 else
690 printf("Couldn't find \"%s %s %s\"\n",
691 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
692 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
693 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
694 return (f);
695 }
696 }
697 return (NULL);
698}