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("$FreeBSD$"); 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} 699