1 /* $NetBSD: pf_osfp.c,v 1.13 2017/01/16 15:46:19 christos Exp $ */
2 /* $OpenBSD: pf_osfp.c,v 1.12 2006/12/13 18:14:10 itojun Exp $ */
3
4 /*
5 * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 *
19 */
20
21 #include <sys/cdefs.h>
22 __KERNEL_RCSID(0, "$NetBSD: pf_osfp.c,v 1.13 2017/01/16 15:46:19 christos Exp $");
23
24 #ifdef _KERNEL_OPT
25 #include "opt_inet.h"
26 #endif
27
28 #include <sys/param.h>
29 #include <sys/socket.h>
30 #ifdef _KERNEL
31 # include <sys/systm.h>
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 # define DPFPRINTF(format, x...) \
51 if (pf_status.debug >= PF_DEBUG_NOISY) \
52 printf(format , ##x)
53 typedef struct pool pool_t;
54
55 #else
56 /* Userland equivalents so we can lend code to tcpdump et al. */
57
58 # include <arpa/inet.h>
59 # include <errno.h>
60 # include <stdio.h>
61 # include <stdlib.h>
62 # include <string.h>
63 # include <netdb.h>
64 # define pool_t int
65 # define pool_get(pool, flags) malloc(*(pool))
66 # define pool_put(pool, item) free(item)
67 # define pool_init(pool, size, a, ao, f, m, p) (*(pool)) = (size)
68
69 # ifdef PFDEBUG
70 # include <sys/stdarg.h>
71 # define DPFPRINTF(format, x...) fprintf(stderr, format , ##x)
72 # else
73 # define DPFPRINTF(format, x...) ((void)0)
74 # endif /* PFDEBUG */
75 #endif /* _KERNEL */
76
77
78 SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
79 pool_t pf_osfp_entry_pl;
80 pool_t pf_osfp_pl;
81
82 struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *,
83 struct pf_os_fingerprint *, u_int8_t);
84 struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *,
85 struct pf_os_fingerprint *);
86 void pf_osfp_insert(struct pf_osfp_list *,
87 struct pf_os_fingerprint *);
88
89
90 #ifdef _KERNEL
91 /*
92 * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
93 * Returns the list of possible OSes.
94 */
95 struct pf_osfp_enlist *
pf_osfp_fingerprint(struct pf_pdesc * pd,struct mbuf * m,int off,const struct tcphdr * tcp)96 pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
97 const struct tcphdr *tcp)
98 {
99 struct ip *ip;
100 struct ip6_hdr *ip6;
101 char hdr[60];
102
103 if ((pd->af != PF_INET && pd->af != PF_INET6) ||
104 pd->proto != IPPROTO_TCP || (tcp->th_off << 2) < sizeof(*tcp))
105 return (NULL);
106
107 if (pd->af == PF_INET) {
108 ip = mtod(m, struct ip *);
109 ip6 = (struct ip6_hdr *)NULL;
110 } else {
111 ip = (struct ip *)NULL;
112 ip6 = mtod(m, struct ip6_hdr *);
113 }
114 if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
115 pd->af)) return (NULL);
116
117 return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
118 }
119 #endif /* _KERNEL */
120
121 struct pf_osfp_enlist *
pf_osfp_fingerprint_hdr(const struct ip * ip,const struct ip6_hdr * ip6,const struct tcphdr * tcp)122 pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6, const struct tcphdr *tcp)
123 {
124 struct pf_os_fingerprint fp, *fpresult;
125 int cnt, optlen = 0;
126 const u_int8_t *optp;
127 #ifdef _KERNEL
128 char srcname[128];
129 #else
130 char srcname[NI_MAXHOST];
131 #endif
132
133 if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
134 return (NULL);
135 if (ip) {
136 if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
137 return (NULL);
138 }
139
140 memset(&fp, 0, sizeof(fp));
141
142 if (ip) {
143 #ifndef _KERNEL
144 struct sockaddr_in sin;
145 #endif
146
147 fp.fp_psize = ntohs(ip->ip_len);
148 fp.fp_ttl = ip->ip_ttl;
149 if (ip->ip_off & htons(IP_DF))
150 fp.fp_flags |= PF_OSFP_DF;
151 #ifdef _KERNEL
152 strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
153 #else
154 memset(&sin, 0, sizeof(sin));
155 sin.sin_family = AF_INET;
156 sin.sin_len = sizeof(struct sockaddr_in);
157 sin.sin_addr = ip->ip_src;
158 (void)getnameinfo((struct sockaddr *)&sin,
159 sizeof(struct sockaddr_in), srcname, sizeof(srcname),
160 NULL, 0, NI_NUMERICHOST);
161 #endif
162 }
163 #ifdef INET6
164 else if (ip6) {
165 #ifndef _KERNEL
166 struct sockaddr_in6 sin6;
167 #endif
168
169 /* jumbo payload? */
170 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
171 fp.fp_ttl = ip6->ip6_hlim;
172 fp.fp_flags |= PF_OSFP_DF;
173 fp.fp_flags |= PF_OSFP_INET6;
174 #ifdef _KERNEL
175 in6_print(srcname, sizeof(srcname),
176 (const struct in6_addr *)&ip6->ip6_src);
177 #else
178 memset(&sin6, 0, sizeof(sin6));
179 sin6.sin6_family = AF_INET6;
180 sin6.sin6_len = sizeof(struct sockaddr_in6);
181 sin6.sin6_addr = ip6->ip6_src;
182 (void)getnameinfo((struct sockaddr *)&sin6,
183 sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
184 NULL, 0, NI_NUMERICHOST);
185 #endif
186 }
187 #endif
188 else
189 return (NULL);
190 fp.fp_wsize = ntohs(tcp->th_win);
191
192
193 cnt = (tcp->th_off << 2) - sizeof(*tcp);
194 optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
195 for (; cnt > 0; cnt -= optlen, optp += optlen) {
196 if (*optp == TCPOPT_EOL)
197 break;
198
199 fp.fp_optcnt++;
200 if (*optp == TCPOPT_NOP) {
201 fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
202 PF_OSFP_TCPOPT_NOP;
203 optlen = 1;
204 } else {
205 if (cnt < 2)
206 return (NULL);
207 optlen = optp[1];
208 if (optlen > cnt || optlen < 2)
209 return (NULL);
210 switch (*optp) {
211 case TCPOPT_MAXSEG:
212 if (optlen >= TCPOLEN_MAXSEG)
213 memcpy(&fp.fp_mss, &optp[2],
214 sizeof(fp.fp_mss));
215 fp.fp_tcpopts = (fp.fp_tcpopts <<
216 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
217 NTOHS(fp.fp_mss);
218 break;
219 case TCPOPT_WINDOW:
220 if (optlen >= TCPOLEN_WINDOW)
221 memcpy(&fp.fp_wscale, &optp[2],
222 sizeof(fp.fp_wscale));
223 NTOHS(fp.fp_wscale);
224 fp.fp_tcpopts = (fp.fp_tcpopts <<
225 PF_OSFP_TCPOPT_BITS) |
226 PF_OSFP_TCPOPT_WSCALE;
227 break;
228 case TCPOPT_SACK_PERMITTED:
229 fp.fp_tcpopts = (fp.fp_tcpopts <<
230 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
231 break;
232 case TCPOPT_TIMESTAMP:
233 if (optlen >= TCPOLEN_TIMESTAMP) {
234 u_int32_t ts;
235 memcpy(&ts, &optp[2], sizeof(ts));
236 if (ts == 0)
237 fp.fp_flags |= PF_OSFP_TS0;
238
239 }
240 fp.fp_tcpopts = (fp.fp_tcpopts <<
241 PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
242 break;
243 default:
244 return (NULL);
245 }
246 }
247 optlen = MAX(optlen, 1); /* paranoia */
248 }
249
250 DPFPRINTF("fingerprinted %s:%d %d:%d:%d:%d:%llx (%d) "
251 "(TS=%s,M=%s%d,W=%s%d)\n",
252 srcname, ntohs(tcp->th_sport),
253 fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
254 fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
255 (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
256 (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
257 (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
258 fp.fp_mss,
259 (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
260 (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
261 fp.fp_wscale);
262
263 if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
264 PF_OSFP_MAXTTL_OFFSET)))
265 return (&fpresult->fp_oses);
266 return (NULL);
267 }
268
269 /* Match a fingerprint ID against a list of OSes */
270 int
pf_osfp_match(struct pf_osfp_enlist * list,pf_osfp_t os)271 pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
272 {
273 struct pf_osfp_entry *entry;
274 int os_class, os_version, os_subtype;
275 int en_class, en_version, en_subtype;
276
277 if (os == PF_OSFP_ANY)
278 return (1);
279 if (list == NULL) {
280 DPFPRINTF("osfp no match against %x\n", os);
281 return (os == PF_OSFP_UNKNOWN);
282 }
283 PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
284 SLIST_FOREACH(entry, list, fp_entry) {
285 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
286 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
287 (os_version == PF_OSFP_ANY || en_version == os_version) &&
288 (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
289 DPFPRINTF("osfp matched %s %s %s %x==%x\n",
290 entry->fp_class_nm, entry->fp_version_nm,
291 entry->fp_subtype_nm, os, entry->fp_os);
292 return (1);
293 }
294 }
295 DPFPRINTF("fingerprint 0x%x didn't match\n", os);
296 return (0);
297 }
298
299 /* Initialize the OS fingerprint system */
300 void
pf_osfp_initialize(void)301 pf_osfp_initialize(void)
302 {
303 #ifdef __NetBSD__
304 pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
305 "pfosfpen", &pool_allocator_nointr, IPL_NONE);
306 pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
307 "pfosfp", &pool_allocator_nointr, IPL_NONE);
308 #else
309 pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
310 "pfosfpen", &pool_allocator_nointr);
311 pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
312 "pfosfp", &pool_allocator_nointr);
313 #endif /* !__NetBSD__ */
314 SLIST_INIT(&pf_osfp_list);
315 }
316
317 #ifdef _MODULE
318 void
pf_osfp_destroy(void)319 pf_osfp_destroy(void)
320 {
321 pf_osfp_flush();
322
323 pool_destroy(&pf_osfp_pl);
324 pool_destroy(&pf_osfp_entry_pl);
325 }
326 #endif /* _MODULE */
327
328 /* Flush the fingerprint list */
329 void
pf_osfp_flush(void)330 pf_osfp_flush(void)
331 {
332 struct pf_os_fingerprint *fp;
333 struct pf_osfp_entry *entry;
334
335 while ((fp = SLIST_FIRST(&pf_osfp_list))) {
336 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
337 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
338 SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
339 pool_put(&pf_osfp_entry_pl, entry);
340 }
341 pool_put(&pf_osfp_pl, fp);
342 }
343 }
344
345
346 /* Add a fingerprint */
347 int
pf_osfp_add(struct pf_osfp_ioctl * fpioc)348 pf_osfp_add(struct pf_osfp_ioctl *fpioc)
349 {
350 struct pf_os_fingerprint *fp, fpadd;
351 struct pf_osfp_entry *entry;
352
353 memset(&fpadd, 0, sizeof(fpadd));
354 fpadd.fp_tcpopts = fpioc->fp_tcpopts;
355 fpadd.fp_wsize = fpioc->fp_wsize;
356 fpadd.fp_psize = fpioc->fp_psize;
357 fpadd.fp_mss = fpioc->fp_mss;
358 fpadd.fp_flags = fpioc->fp_flags;
359 fpadd.fp_optcnt = fpioc->fp_optcnt;
360 fpadd.fp_wscale = fpioc->fp_wscale;
361 fpadd.fp_ttl = fpioc->fp_ttl;
362
363 DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
364 "(TS=%s,M=%s%d,W=%s%d) %x\n",
365 fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
366 fpioc->fp_os.fp_subtype_nm,
367 (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
368 (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
369 (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
370 (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
371 fpadd.fp_wsize,
372 fpadd.fp_ttl,
373 (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
374 (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
375 (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
376 fpadd.fp_psize,
377 (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
378 (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
379 (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
380 (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
381 fpadd.fp_mss,
382 (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
383 (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
384 fpadd.fp_wscale,
385 fpioc->fp_os.fp_os);
386
387
388 if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
389 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
390 if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
391 return (EEXIST);
392 }
393 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL)
394 return (ENOMEM);
395 } else {
396 if ((fp = pool_get(&pf_osfp_pl, PR_NOWAIT)) == NULL)
397 return (ENOMEM);
398 memset(fp, 0, sizeof(*fp));
399 fp->fp_tcpopts = fpioc->fp_tcpopts;
400 fp->fp_wsize = fpioc->fp_wsize;
401 fp->fp_psize = fpioc->fp_psize;
402 fp->fp_mss = fpioc->fp_mss;
403 fp->fp_flags = fpioc->fp_flags;
404 fp->fp_optcnt = fpioc->fp_optcnt;
405 fp->fp_wscale = fpioc->fp_wscale;
406 fp->fp_ttl = fpioc->fp_ttl;
407 SLIST_INIT(&fp->fp_oses);
408 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL) {
409 pool_put(&pf_osfp_pl, fp);
410 return (ENOMEM);
411 }
412 pf_osfp_insert(&pf_osfp_list, fp);
413 }
414 memcpy(entry, &fpioc->fp_os, sizeof(*entry));
415
416 /* Make sure the strings are NUL terminated */
417 entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
418 entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
419 entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
420
421 SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
422
423 #ifdef PFDEBUG
424 if ((fp = pf_osfp_validate()))
425 printf("Invalid fingerprint list\n");
426 #endif /* PFDEBUG */
427 return (0);
428 }
429
430
431 /* Find a fingerprint in the list */
432 struct pf_os_fingerprint *
pf_osfp_find(struct pf_osfp_list * list,struct pf_os_fingerprint * find,u_int8_t ttldiff)433 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
434 u_int8_t ttldiff)
435 {
436 struct pf_os_fingerprint *f;
437
438 #define MATCH_INT(_MOD, _DC, _field) \
439 if ((f->fp_flags & _DC) == 0) { \
440 if ((f->fp_flags & _MOD) == 0) { \
441 if (f->_field != find->_field) \
442 continue; \
443 } else { \
444 if (f->_field == 0 || find->_field % f->_field) \
445 continue; \
446 } \
447 }
448
449 SLIST_FOREACH(f, list, fp_next) {
450 if (f->fp_tcpopts != find->fp_tcpopts ||
451 f->fp_optcnt != find->fp_optcnt ||
452 f->fp_ttl < find->fp_ttl ||
453 f->fp_ttl - find->fp_ttl > ttldiff ||
454 (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
455 (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
456 continue;
457
458 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
459 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
460 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
461 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
462 if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
463 if (find->fp_mss == 0)
464 continue;
465
466 /* Some "smart" NAT devices and DSL routers will tweak the MSS size and
467 * will set it to whatever is suitable for the link type.
468 */
469 #define SMART_MSS 1460
470 if ((find->fp_wsize % find->fp_mss ||
471 find->fp_wsize / find->fp_mss !=
472 f->fp_wsize) &&
473 (find->fp_wsize % SMART_MSS ||
474 find->fp_wsize / SMART_MSS !=
475 f->fp_wsize))
476 continue;
477 } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
478 if (find->fp_mss == 0)
479 continue;
480
481 #define MTUOFF (sizeof(struct ip) + sizeof(struct tcphdr))
482 #define SMART_MTU (SMART_MSS + MTUOFF)
483 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
484 find->fp_wsize / (find->fp_mss + MTUOFF) !=
485 f->fp_wsize) &&
486 (find->fp_wsize % SMART_MTU ||
487 find->fp_wsize / SMART_MTU !=
488 f->fp_wsize))
489 continue;
490 } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
491 if (f->fp_wsize == 0 || find->fp_wsize %
492 f->fp_wsize)
493 continue;
494 } else {
495 if (f->fp_wsize != find->fp_wsize)
496 continue;
497 }
498 }
499 return (f);
500 }
501
502 return (NULL);
503 }
504
505 /* Find an exact fingerprint in the list */
506 struct pf_os_fingerprint *
pf_osfp_find_exact(struct pf_osfp_list * list,struct pf_os_fingerprint * find)507 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
508 {
509 struct pf_os_fingerprint *f;
510
511 SLIST_FOREACH(f, list, fp_next) {
512 if (f->fp_tcpopts == find->fp_tcpopts &&
513 f->fp_wsize == find->fp_wsize &&
514 f->fp_psize == find->fp_psize &&
515 f->fp_mss == find->fp_mss &&
516 f->fp_flags == find->fp_flags &&
517 f->fp_optcnt == find->fp_optcnt &&
518 f->fp_wscale == find->fp_wscale &&
519 f->fp_ttl == find->fp_ttl)
520 return (f);
521 }
522
523 return (NULL);
524 }
525
526 /* Insert a fingerprint into the list */
527 void
pf_osfp_insert(struct pf_osfp_list * list,struct pf_os_fingerprint * ins)528 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
529 {
530 struct pf_os_fingerprint *f, *prev = NULL;
531
532 /* XXX need to go semi tree based. can key on tcp options */
533
534 SLIST_FOREACH(f, list, fp_next)
535 prev = f;
536 if (prev)
537 SLIST_INSERT_AFTER(prev, ins, fp_next);
538 else
539 SLIST_INSERT_HEAD(list, ins, fp_next);
540 }
541
542 /* Fill a fingerprint by its number (from an ioctl) */
543 int
pf_osfp_get(struct pf_osfp_ioctl * fpioc)544 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
545 {
546 struct pf_os_fingerprint *fp;
547 struct pf_osfp_entry *entry;
548 int num = fpioc->fp_getnum;
549 int i = 0;
550
551
552 memset(fpioc, 0, sizeof(*fpioc));
553 SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
554 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
555 if (i++ == num) {
556 fpioc->fp_mss = fp->fp_mss;
557 fpioc->fp_wsize = fp->fp_wsize;
558 fpioc->fp_flags = fp->fp_flags;
559 fpioc->fp_psize = fp->fp_psize;
560 fpioc->fp_ttl = fp->fp_ttl;
561 fpioc->fp_wscale = fp->fp_wscale;
562 fpioc->fp_getnum = num;
563 memcpy(&fpioc->fp_os, entry,
564 sizeof(fpioc->fp_os));
565 return (0);
566 }
567 }
568 }
569
570 return (EBUSY);
571 }
572
573
574 /* Validate that each signature is reachable */
575 struct pf_os_fingerprint *
pf_osfp_validate(void)576 pf_osfp_validate(void)
577 {
578 struct pf_os_fingerprint *f, *f2, find;
579
580 SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
581 memcpy(&find, f, sizeof(find));
582
583 /* We do a few MSS/th_win percolations to make things unique */
584 if (find.fp_mss == 0)
585 find.fp_mss = 128;
586 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
587 find.fp_wsize *= find.fp_mss;
588 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
589 find.fp_wsize *= (find.fp_mss + 40);
590 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
591 find.fp_wsize *= 2;
592 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
593 if (f2)
594 printf("Found \"%s %s %s\" instead of "
595 "\"%s %s %s\"\n",
596 SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
597 SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
598 SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
599 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
600 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
601 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
602 else
603 printf("Couldn't find \"%s %s %s\"\n",
604 SLIST_FIRST(&f->fp_oses)->fp_class_nm,
605 SLIST_FIRST(&f->fp_oses)->fp_version_nm,
606 SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
607 return (f);
608 }
609 }
610 return (NULL);
611 }
612