66 67#include <sys/socketvar.h> 68 69#include <security/mac/mac_framework.h> 70 71static int ip_dosourceroute = 0; 72SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 73 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 74 75static int ip_acceptsourceroute = 0; 76SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 77 CTLFLAG_RW, &ip_acceptsourceroute, 0, 78 "Enable accepting source routed IP packets"); 79 80int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 81SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 82 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 83 84static void save_rte(struct mbuf *m, u_char *, struct in_addr); 85 86/* 87 * Do option processing on a datagram, possibly discarding it if bad options 88 * are encountered, or forwarding it if source-routed. 89 * 90 * The pass argument is used when operating in the IPSTEALTH mode to tell 91 * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 92 * reason for as many as two passes is that when doing IPSTEALTH, non-routing 93 * options should be processed only if the packet is for us. 94 * 95 * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 96 * processed further. 97 */ 98int 99ip_dooptions(struct mbuf *m, int pass) 100{ 101 INIT_VNET_INET(curvnet); 102 struct ip *ip = mtod(m, struct ip *); 103 u_char *cp; 104 struct in_ifaddr *ia; 105 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 106 struct in_addr *sin, dst; 107 n_time ntime; 108 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 109 110 /* Ignore or reject packets with IP options. */ 111 if (ip_doopts == 0) 112 return 0; 113 else if (ip_doopts == 2) { 114 type = ICMP_UNREACH; 115 code = ICMP_UNREACH_FILTER_PROHIB; 116 goto bad; 117 } 118 119 dst = ip->ip_dst; 120 cp = (u_char *)(ip + 1); 121 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 122 for (; cnt > 0; cnt -= optlen, cp += optlen) { 123 opt = cp[IPOPT_OPTVAL]; 124 if (opt == IPOPT_EOL) 125 break; 126 if (opt == IPOPT_NOP) 127 optlen = 1; 128 else { 129 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 130 code = &cp[IPOPT_OLEN] - (u_char *)ip; 131 goto bad; 132 } 133 optlen = cp[IPOPT_OLEN]; 134 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 135 code = &cp[IPOPT_OLEN] - (u_char *)ip; 136 goto bad; 137 } 138 } 139 switch (opt) { 140 141 default: 142 break; 143 144 /* 145 * Source routing with record. Find interface with current 146 * destination address. If none on this machine then drop if 147 * strictly routed, or do nothing if loosely routed. Record 148 * interface address and bring up next address component. If 149 * strictly routed make sure next address is on directly 150 * accessible net. 151 */ 152 case IPOPT_LSRR: 153 case IPOPT_SSRR: 154#ifdef IPSTEALTH 155 if (V_ipstealth && pass > 0) 156 break; 157#endif 158 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 159 code = &cp[IPOPT_OLEN] - (u_char *)ip; 160 goto bad; 161 } 162 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 163 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 164 goto bad; 165 } 166 ipaddr.sin_addr = ip->ip_dst; 167 ia = (struct in_ifaddr *) 168 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 169 if (ia == NULL) { 170 if (opt == IPOPT_SSRR) { 171 type = ICMP_UNREACH; 172 code = ICMP_UNREACH_SRCFAIL; 173 goto bad; 174 } 175 if (!ip_dosourceroute) 176 goto nosourcerouting; 177 /* 178 * Loose routing, and not at next destination 179 * yet; nothing to do except forward. 180 */ 181 break; 182 } 183 off--; /* 0 origin */ 184 if (off > optlen - (int)sizeof(struct in_addr)) { 185 /* 186 * End of source route. Should be for us. 187 */ 188 if (!ip_acceptsourceroute) 189 goto nosourcerouting; 190 save_rte(m, cp, ip->ip_src); 191 break; 192 } 193#ifdef IPSTEALTH 194 if (V_ipstealth) 195 goto dropit; 196#endif 197 if (!ip_dosourceroute) { 198 if (V_ipforwarding) { 199 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 200 /* 201 * Acting as a router, so generate 202 * ICMP 203 */ 204nosourcerouting: 205 strcpy(buf, inet_ntoa(ip->ip_dst)); 206 log(LOG_WARNING, 207 "attempted source route from %s to %s\n", 208 inet_ntoa(ip->ip_src), buf); 209 type = ICMP_UNREACH; 210 code = ICMP_UNREACH_SRCFAIL; 211 goto bad; 212 } else { 213 /* 214 * Not acting as a router, so 215 * silently drop. 216 */ 217#ifdef IPSTEALTH 218dropit: 219#endif 220 V_ipstat.ips_cantforward++; 221 m_freem(m); 222 return (1); 223 } 224 } 225 226 /* 227 * locate outgoing interface 228 */ 229 (void)memcpy(&ipaddr.sin_addr, cp + off, 230 sizeof(ipaddr.sin_addr)); 231 232 if (opt == IPOPT_SSRR) { 233#define INA struct in_ifaddr * 234#define SA struct sockaddr * 235 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 236 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 237 } else 238/* XXX MRT 0 for routing */ 239 ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m)); 240 if (ia == NULL) { 241 type = ICMP_UNREACH; 242 code = ICMP_UNREACH_SRCFAIL; 243 goto bad; 244 } 245 ip->ip_dst = ipaddr.sin_addr; 246 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 247 sizeof(struct in_addr)); 248 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 249 /* 250 * Let ip_intr's mcast routing check handle mcast pkts 251 */ 252 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 253 break; 254 255 case IPOPT_RR: 256#ifdef IPSTEALTH 257 if (V_ipstealth && pass == 0) 258 break; 259#endif 260 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 261 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 262 goto bad; 263 } 264 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 265 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 266 goto bad; 267 } 268 /* 269 * If no space remains, ignore. 270 */ 271 off--; /* 0 origin */ 272 if (off > optlen - (int)sizeof(struct in_addr)) 273 break; 274 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 275 sizeof(ipaddr.sin_addr)); 276 /* 277 * Locate outgoing interface; if we're the 278 * destination, use the incoming interface (should be 279 * same). 280 */ 281 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 282 (ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m))) == NULL) { 283 type = ICMP_UNREACH; 284 code = ICMP_UNREACH_HOST; 285 goto bad; 286 } 287 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 288 sizeof(struct in_addr)); 289 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 290 break; 291 292 case IPOPT_TS: 293#ifdef IPSTEALTH 294 if (V_ipstealth && pass == 0) 295 break; 296#endif 297 code = cp - (u_char *)ip; 298 if (optlen < 4 || optlen > 40) { 299 code = &cp[IPOPT_OLEN] - (u_char *)ip; 300 goto bad; 301 } 302 if ((off = cp[IPOPT_OFFSET]) < 5) { 303 code = &cp[IPOPT_OLEN] - (u_char *)ip; 304 goto bad; 305 } 306 if (off > optlen - (int)sizeof(int32_t)) { 307 cp[IPOPT_OFFSET + 1] += (1 << 4); 308 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 309 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 310 goto bad; 311 } 312 break; 313 } 314 off--; /* 0 origin */ 315 sin = (struct in_addr *)(cp + off); 316 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 317 318 case IPOPT_TS_TSONLY: 319 break; 320 321 case IPOPT_TS_TSANDADDR: 322 if (off + sizeof(n_time) + 323 sizeof(struct in_addr) > optlen) { 324 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 325 goto bad; 326 } 327 ipaddr.sin_addr = dst; 328 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 329 m->m_pkthdr.rcvif); 330 if (ia == NULL) 331 continue; 332 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 333 sizeof(struct in_addr)); 334 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 335 off += sizeof(struct in_addr); 336 break; 337 338 case IPOPT_TS_PRESPEC: 339 if (off + sizeof(n_time) + 340 sizeof(struct in_addr) > optlen) { 341 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 342 goto bad; 343 } 344 (void)memcpy(&ipaddr.sin_addr, sin, 345 sizeof(struct in_addr)); 346 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 347 continue; 348 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 349 off += sizeof(struct in_addr); 350 break; 351 352 default: 353 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 354 goto bad; 355 } 356 ntime = iptime(); 357 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 358 cp[IPOPT_OFFSET] += sizeof(n_time); 359 } 360 } 361 if (forward && V_ipforwarding) { 362 ip_forward(m, 1); 363 return (1); 364 } 365 return (0); 366bad: 367 icmp_error(m, type, code, 0, 0); 368 V_ipstat.ips_badoptions++; 369 return (1); 370} 371 372/* 373 * Save incoming source route for use in replies, to be picked up later by 374 * ip_srcroute if the receiver is interested. 375 */ 376static void 377save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 378{ 379 unsigned olen; 380 struct ipopt_tag *opts; 381 382 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 383 sizeof(struct ipopt_tag), M_NOWAIT); 384 if (opts == NULL) 385 return; 386 387 olen = option[IPOPT_OLEN]; 388 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 389 m_tag_free((struct m_tag *)opts); 390 return; 391 } 392 bcopy(option, opts->ip_srcrt.srcopt, olen); 393 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 394 opts->ip_srcrt.dst = dst; 395 m_tag_prepend(m, (struct m_tag *)opts); 396} 397 398/* 399 * Retrieve incoming source route for use in replies, in the same form used 400 * by setsockopt. The first hop is placed before the options, will be 401 * removed later. 402 */ 403struct mbuf * 404ip_srcroute(struct mbuf *m0) 405{ 406 struct in_addr *p, *q; 407 struct mbuf *m; 408 struct ipopt_tag *opts; 409 410 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 411 if (opts == NULL) 412 return (NULL); 413 414 if (opts->ip_nhops == 0) 415 return (NULL); 416 m = m_get(M_DONTWAIT, MT_DATA); 417 if (m == NULL) 418 return (NULL); 419 420#define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 421 422 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 423 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 424 sizeof(struct in_addr) + OPTSIZ; 425 426 /* 427 * First, save first hop for return route. 428 */ 429 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 430 *(mtod(m, struct in_addr *)) = *p--; 431 432 /* 433 * Copy option fields and padding (nop) to mbuf. 434 */ 435 opts->ip_srcrt.nop = IPOPT_NOP; 436 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 437 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 438 &(opts->ip_srcrt.nop), OPTSIZ); 439 q = (struct in_addr *)(mtod(m, caddr_t) + 440 sizeof(struct in_addr) + OPTSIZ); 441#undef OPTSIZ 442 /* 443 * Record return path as an IP source route, reversing the path 444 * (pointers are now aligned). 445 */ 446 while (p >= opts->ip_srcrt.route) { 447 *q++ = *p--; 448 } 449 /* 450 * Last hop goes to final destination. 451 */ 452 *q = opts->ip_srcrt.dst; 453 m_tag_delete(m0, (struct m_tag *)opts); 454 return (m); 455} 456 457/* 458 * Strip out IP options, at higher level protocol in the kernel. Second 459 * argument is buffer to which options will be moved, and return value is 460 * their length. 461 * 462 * XXX should be deleted; last arg currently ignored. 463 */ 464void 465ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 466{ 467 int i; 468 struct ip *ip = mtod(m, struct ip *); 469 caddr_t opts; 470 int olen; 471 472 olen = (ip->ip_hl << 2) - sizeof (struct ip); 473 opts = (caddr_t)(ip + 1); 474 i = m->m_len - (sizeof (struct ip) + olen); 475 bcopy(opts + olen, opts, (unsigned)i); 476 m->m_len -= olen; 477 if (m->m_flags & M_PKTHDR) 478 m->m_pkthdr.len -= olen; 479 ip->ip_v = IPVERSION; 480 ip->ip_hl = sizeof(struct ip) >> 2; 481} 482 483/* 484 * Insert IP options into preformed packet. Adjust IP destination as 485 * required for IP source routing, as indicated by a non-zero in_addr at the 486 * start of the options. 487 * 488 * XXX This routine assumes that the packet has no options in place. 489 */ 490struct mbuf * 491ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 492{ 493 struct ipoption *p = mtod(opt, struct ipoption *); 494 struct mbuf *n; 495 struct ip *ip = mtod(m, struct ip *); 496 unsigned optlen; 497 498 optlen = opt->m_len - sizeof(p->ipopt_dst); 499 if (optlen + ip->ip_len > IP_MAXPACKET) { 500 *phlen = 0; 501 return (m); /* XXX should fail */ 502 } 503 if (p->ipopt_dst.s_addr) 504 ip->ip_dst = p->ipopt_dst; 505 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 506 MGETHDR(n, M_DONTWAIT, MT_DATA); 507 if (n == NULL) { 508 *phlen = 0; 509 return (m); 510 } 511 M_MOVE_PKTHDR(n, m); 512 n->m_pkthdr.rcvif = NULL; 513 n->m_pkthdr.len += optlen; 514 m->m_len -= sizeof(struct ip); 515 m->m_data += sizeof(struct ip); 516 n->m_next = m; 517 m = n; 518 m->m_len = optlen + sizeof(struct ip); 519 m->m_data += max_linkhdr; 520 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 521 } else { 522 m->m_data -= optlen; 523 m->m_len += optlen; 524 m->m_pkthdr.len += optlen; 525 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 526 } 527 ip = mtod(m, struct ip *); 528 bcopy(p->ipopt_list, ip + 1, optlen); 529 *phlen = sizeof(struct ip) + optlen; 530 ip->ip_v = IPVERSION; 531 ip->ip_hl = *phlen >> 2; 532 ip->ip_len += optlen; 533 return (m); 534} 535 536/* 537 * Copy options from ip to jp, omitting those not copied during 538 * fragmentation. 539 */ 540int 541ip_optcopy(struct ip *ip, struct ip *jp) 542{ 543 u_char *cp, *dp; 544 int opt, optlen, cnt; 545 546 cp = (u_char *)(ip + 1); 547 dp = (u_char *)(jp + 1); 548 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 549 for (; cnt > 0; cnt -= optlen, cp += optlen) { 550 opt = cp[0]; 551 if (opt == IPOPT_EOL) 552 break; 553 if (opt == IPOPT_NOP) { 554 /* Preserve for IP mcast tunnel's LSRR alignment. */ 555 *dp++ = IPOPT_NOP; 556 optlen = 1; 557 continue; 558 } 559 560 KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 561 ("ip_optcopy: malformed ipv4 option")); 562 optlen = cp[IPOPT_OLEN]; 563 KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 564 ("ip_optcopy: malformed ipv4 option")); 565 566 /* Bogus lengths should have been caught by ip_dooptions. */ 567 if (optlen > cnt) 568 optlen = cnt; 569 if (IPOPT_COPIED(opt)) { 570 bcopy(cp, dp, optlen); 571 dp += optlen; 572 } 573 } 574 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 575 *dp++ = IPOPT_EOL; 576 return (optlen); 577} 578 579/* 580 * Set up IP options in pcb for insertion in output packets. Store in mbuf 581 * with pointer in pcbopt, adding pseudo-option with destination address if 582 * source routed. 583 */ 584int 585ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 586{ 587 int cnt, optlen; 588 u_char *cp; 589 struct mbuf **pcbopt; 590 u_char opt; 591 592 INP_WLOCK_ASSERT(inp); 593 594 pcbopt = &inp->inp_options; 595 596 /* turn off any old options */ 597 if (*pcbopt) 598 (void)m_free(*pcbopt); 599 *pcbopt = 0; 600 if (m == NULL || m->m_len == 0) { 601 /* 602 * Only turning off any previous options. 603 */ 604 if (m != NULL) 605 (void)m_free(m); 606 return (0); 607 } 608 609 if (m->m_len % sizeof(int32_t)) 610 goto bad; 611 /* 612 * IP first-hop destination address will be stored before actual 613 * options; move other options back and clear it when none present. 614 */ 615 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 616 goto bad; 617 cnt = m->m_len; 618 m->m_len += sizeof(struct in_addr); 619 cp = mtod(m, u_char *) + sizeof(struct in_addr); 620 bcopy(mtod(m, void *), cp, (unsigned)cnt); 621 bzero(mtod(m, void *), sizeof(struct in_addr)); 622 623 for (; cnt > 0; cnt -= optlen, cp += optlen) { 624 opt = cp[IPOPT_OPTVAL]; 625 if (opt == IPOPT_EOL) 626 break; 627 if (opt == IPOPT_NOP) 628 optlen = 1; 629 else { 630 if (cnt < IPOPT_OLEN + sizeof(*cp)) 631 goto bad; 632 optlen = cp[IPOPT_OLEN]; 633 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 634 goto bad; 635 } 636 switch (opt) { 637 638 default: 639 break; 640 641 case IPOPT_LSRR: 642 case IPOPT_SSRR: 643 /* 644 * User process specifies route as: 645 * 646 * ->A->B->C->D 647 * 648 * D must be our final destination (but we can't 649 * check that since we may not have connected yet). 650 * A is first hop destination, which doesn't appear 651 * in actual IP option, but is stored before the 652 * options. 653 */ 654 /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 655 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 656 goto bad; 657 m->m_len -= sizeof(struct in_addr); 658 cnt -= sizeof(struct in_addr); 659 optlen -= sizeof(struct in_addr); 660 cp[IPOPT_OLEN] = optlen; 661 /* 662 * Move first hop before start of options. 663 */ 664 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 665 sizeof(struct in_addr)); 666 /* 667 * Then copy rest of options back 668 * to close up the deleted entry. 669 */ 670 bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 671 &cp[IPOPT_OFFSET+1], 672 (unsigned)cnt - (IPOPT_MINOFF - 1)); 673 break; 674 } 675 } 676 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 677 goto bad; 678 *pcbopt = m; 679 return (0); 680 681bad: 682 (void)m_free(m); 683 return (EINVAL); 684}
| 67 68#include <sys/socketvar.h> 69 70#include <security/mac/mac_framework.h> 71 72static int ip_dosourceroute = 0; 73SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW, 74 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets"); 75 76static int ip_acceptsourceroute = 0; 77SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute, 78 CTLFLAG_RW, &ip_acceptsourceroute, 0, 79 "Enable accepting source routed IP packets"); 80 81int ip_doopts = 1; /* 0 = ignore, 1 = process, 2 = reject */ 82SYSCTL_INT(_net_inet_ip, OID_AUTO, process_options, CTLFLAG_RW, 83 &ip_doopts, 0, "Enable IP options processing ([LS]SRR, RR, TS)"); 84 85static void save_rte(struct mbuf *m, u_char *, struct in_addr); 86 87/* 88 * Do option processing on a datagram, possibly discarding it if bad options 89 * are encountered, or forwarding it if source-routed. 90 * 91 * The pass argument is used when operating in the IPSTEALTH mode to tell 92 * what options to process: [LS]SRR (pass 0) or the others (pass 1). The 93 * reason for as many as two passes is that when doing IPSTEALTH, non-routing 94 * options should be processed only if the packet is for us. 95 * 96 * Returns 1 if packet has been forwarded/freed, 0 if the packet should be 97 * processed further. 98 */ 99int 100ip_dooptions(struct mbuf *m, int pass) 101{ 102 INIT_VNET_INET(curvnet); 103 struct ip *ip = mtod(m, struct ip *); 104 u_char *cp; 105 struct in_ifaddr *ia; 106 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; 107 struct in_addr *sin, dst; 108 n_time ntime; 109 struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; 110 111 /* Ignore or reject packets with IP options. */ 112 if (ip_doopts == 0) 113 return 0; 114 else if (ip_doopts == 2) { 115 type = ICMP_UNREACH; 116 code = ICMP_UNREACH_FILTER_PROHIB; 117 goto bad; 118 } 119 120 dst = ip->ip_dst; 121 cp = (u_char *)(ip + 1); 122 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 123 for (; cnt > 0; cnt -= optlen, cp += optlen) { 124 opt = cp[IPOPT_OPTVAL]; 125 if (opt == IPOPT_EOL) 126 break; 127 if (opt == IPOPT_NOP) 128 optlen = 1; 129 else { 130 if (cnt < IPOPT_OLEN + sizeof(*cp)) { 131 code = &cp[IPOPT_OLEN] - (u_char *)ip; 132 goto bad; 133 } 134 optlen = cp[IPOPT_OLEN]; 135 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) { 136 code = &cp[IPOPT_OLEN] - (u_char *)ip; 137 goto bad; 138 } 139 } 140 switch (opt) { 141 142 default: 143 break; 144 145 /* 146 * Source routing with record. Find interface with current 147 * destination address. If none on this machine then drop if 148 * strictly routed, or do nothing if loosely routed. Record 149 * interface address and bring up next address component. If 150 * strictly routed make sure next address is on directly 151 * accessible net. 152 */ 153 case IPOPT_LSRR: 154 case IPOPT_SSRR: 155#ifdef IPSTEALTH 156 if (V_ipstealth && pass > 0) 157 break; 158#endif 159 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 160 code = &cp[IPOPT_OLEN] - (u_char *)ip; 161 goto bad; 162 } 163 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 164 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 165 goto bad; 166 } 167 ipaddr.sin_addr = ip->ip_dst; 168 ia = (struct in_ifaddr *) 169 ifa_ifwithaddr((struct sockaddr *)&ipaddr); 170 if (ia == NULL) { 171 if (opt == IPOPT_SSRR) { 172 type = ICMP_UNREACH; 173 code = ICMP_UNREACH_SRCFAIL; 174 goto bad; 175 } 176 if (!ip_dosourceroute) 177 goto nosourcerouting; 178 /* 179 * Loose routing, and not at next destination 180 * yet; nothing to do except forward. 181 */ 182 break; 183 } 184 off--; /* 0 origin */ 185 if (off > optlen - (int)sizeof(struct in_addr)) { 186 /* 187 * End of source route. Should be for us. 188 */ 189 if (!ip_acceptsourceroute) 190 goto nosourcerouting; 191 save_rte(m, cp, ip->ip_src); 192 break; 193 } 194#ifdef IPSTEALTH 195 if (V_ipstealth) 196 goto dropit; 197#endif 198 if (!ip_dosourceroute) { 199 if (V_ipforwarding) { 200 char buf[16]; /* aaa.bbb.ccc.ddd\0 */ 201 /* 202 * Acting as a router, so generate 203 * ICMP 204 */ 205nosourcerouting: 206 strcpy(buf, inet_ntoa(ip->ip_dst)); 207 log(LOG_WARNING, 208 "attempted source route from %s to %s\n", 209 inet_ntoa(ip->ip_src), buf); 210 type = ICMP_UNREACH; 211 code = ICMP_UNREACH_SRCFAIL; 212 goto bad; 213 } else { 214 /* 215 * Not acting as a router, so 216 * silently drop. 217 */ 218#ifdef IPSTEALTH 219dropit: 220#endif 221 V_ipstat.ips_cantforward++; 222 m_freem(m); 223 return (1); 224 } 225 } 226 227 /* 228 * locate outgoing interface 229 */ 230 (void)memcpy(&ipaddr.sin_addr, cp + off, 231 sizeof(ipaddr.sin_addr)); 232 233 if (opt == IPOPT_SSRR) { 234#define INA struct in_ifaddr * 235#define SA struct sockaddr * 236 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == NULL) 237 ia = (INA)ifa_ifwithnet((SA)&ipaddr); 238 } else 239/* XXX MRT 0 for routing */ 240 ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m)); 241 if (ia == NULL) { 242 type = ICMP_UNREACH; 243 code = ICMP_UNREACH_SRCFAIL; 244 goto bad; 245 } 246 ip->ip_dst = ipaddr.sin_addr; 247 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 248 sizeof(struct in_addr)); 249 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 250 /* 251 * Let ip_intr's mcast routing check handle mcast pkts 252 */ 253 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr)); 254 break; 255 256 case IPOPT_RR: 257#ifdef IPSTEALTH 258 if (V_ipstealth && pass == 0) 259 break; 260#endif 261 if (optlen < IPOPT_OFFSET + sizeof(*cp)) { 262 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 263 goto bad; 264 } 265 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { 266 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 267 goto bad; 268 } 269 /* 270 * If no space remains, ignore. 271 */ 272 off--; /* 0 origin */ 273 if (off > optlen - (int)sizeof(struct in_addr)) 274 break; 275 (void)memcpy(&ipaddr.sin_addr, &ip->ip_dst, 276 sizeof(ipaddr.sin_addr)); 277 /* 278 * Locate outgoing interface; if we're the 279 * destination, use the incoming interface (should be 280 * same). 281 */ 282 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL && 283 (ia = ip_rtaddr(ipaddr.sin_addr, M_GETFIB(m))) == NULL) { 284 type = ICMP_UNREACH; 285 code = ICMP_UNREACH_HOST; 286 goto bad; 287 } 288 (void)memcpy(cp + off, &(IA_SIN(ia)->sin_addr), 289 sizeof(struct in_addr)); 290 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 291 break; 292 293 case IPOPT_TS: 294#ifdef IPSTEALTH 295 if (V_ipstealth && pass == 0) 296 break; 297#endif 298 code = cp - (u_char *)ip; 299 if (optlen < 4 || optlen > 40) { 300 code = &cp[IPOPT_OLEN] - (u_char *)ip; 301 goto bad; 302 } 303 if ((off = cp[IPOPT_OFFSET]) < 5) { 304 code = &cp[IPOPT_OLEN] - (u_char *)ip; 305 goto bad; 306 } 307 if (off > optlen - (int)sizeof(int32_t)) { 308 cp[IPOPT_OFFSET + 1] += (1 << 4); 309 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) { 310 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 311 goto bad; 312 } 313 break; 314 } 315 off--; /* 0 origin */ 316 sin = (struct in_addr *)(cp + off); 317 switch (cp[IPOPT_OFFSET + 1] & 0x0f) { 318 319 case IPOPT_TS_TSONLY: 320 break; 321 322 case IPOPT_TS_TSANDADDR: 323 if (off + sizeof(n_time) + 324 sizeof(struct in_addr) > optlen) { 325 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 326 goto bad; 327 } 328 ipaddr.sin_addr = dst; 329 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, 330 m->m_pkthdr.rcvif); 331 if (ia == NULL) 332 continue; 333 (void)memcpy(sin, &IA_SIN(ia)->sin_addr, 334 sizeof(struct in_addr)); 335 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 336 off += sizeof(struct in_addr); 337 break; 338 339 case IPOPT_TS_PRESPEC: 340 if (off + sizeof(n_time) + 341 sizeof(struct in_addr) > optlen) { 342 code = &cp[IPOPT_OFFSET] - (u_char *)ip; 343 goto bad; 344 } 345 (void)memcpy(&ipaddr.sin_addr, sin, 346 sizeof(struct in_addr)); 347 if (ifa_ifwithaddr((SA)&ipaddr) == NULL) 348 continue; 349 cp[IPOPT_OFFSET] += sizeof(struct in_addr); 350 off += sizeof(struct in_addr); 351 break; 352 353 default: 354 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip; 355 goto bad; 356 } 357 ntime = iptime(); 358 (void)memcpy(cp + off, &ntime, sizeof(n_time)); 359 cp[IPOPT_OFFSET] += sizeof(n_time); 360 } 361 } 362 if (forward && V_ipforwarding) { 363 ip_forward(m, 1); 364 return (1); 365 } 366 return (0); 367bad: 368 icmp_error(m, type, code, 0, 0); 369 V_ipstat.ips_badoptions++; 370 return (1); 371} 372 373/* 374 * Save incoming source route for use in replies, to be picked up later by 375 * ip_srcroute if the receiver is interested. 376 */ 377static void 378save_rte(struct mbuf *m, u_char *option, struct in_addr dst) 379{ 380 unsigned olen; 381 struct ipopt_tag *opts; 382 383 opts = (struct ipopt_tag *)m_tag_get(PACKET_TAG_IPOPTIONS, 384 sizeof(struct ipopt_tag), M_NOWAIT); 385 if (opts == NULL) 386 return; 387 388 olen = option[IPOPT_OLEN]; 389 if (olen > sizeof(opts->ip_srcrt) - (1 + sizeof(dst))) { 390 m_tag_free((struct m_tag *)opts); 391 return; 392 } 393 bcopy(option, opts->ip_srcrt.srcopt, olen); 394 opts->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); 395 opts->ip_srcrt.dst = dst; 396 m_tag_prepend(m, (struct m_tag *)opts); 397} 398 399/* 400 * Retrieve incoming source route for use in replies, in the same form used 401 * by setsockopt. The first hop is placed before the options, will be 402 * removed later. 403 */ 404struct mbuf * 405ip_srcroute(struct mbuf *m0) 406{ 407 struct in_addr *p, *q; 408 struct mbuf *m; 409 struct ipopt_tag *opts; 410 411 opts = (struct ipopt_tag *)m_tag_find(m0, PACKET_TAG_IPOPTIONS, NULL); 412 if (opts == NULL) 413 return (NULL); 414 415 if (opts->ip_nhops == 0) 416 return (NULL); 417 m = m_get(M_DONTWAIT, MT_DATA); 418 if (m == NULL) 419 return (NULL); 420 421#define OPTSIZ (sizeof(opts->ip_srcrt.nop) + sizeof(opts->ip_srcrt.srcopt)) 422 423 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ 424 m->m_len = opts->ip_nhops * sizeof(struct in_addr) + 425 sizeof(struct in_addr) + OPTSIZ; 426 427 /* 428 * First, save first hop for return route. 429 */ 430 p = &(opts->ip_srcrt.route[opts->ip_nhops - 1]); 431 *(mtod(m, struct in_addr *)) = *p--; 432 433 /* 434 * Copy option fields and padding (nop) to mbuf. 435 */ 436 opts->ip_srcrt.nop = IPOPT_NOP; 437 opts->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; 438 (void)memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), 439 &(opts->ip_srcrt.nop), OPTSIZ); 440 q = (struct in_addr *)(mtod(m, caddr_t) + 441 sizeof(struct in_addr) + OPTSIZ); 442#undef OPTSIZ 443 /* 444 * Record return path as an IP source route, reversing the path 445 * (pointers are now aligned). 446 */ 447 while (p >= opts->ip_srcrt.route) { 448 *q++ = *p--; 449 } 450 /* 451 * Last hop goes to final destination. 452 */ 453 *q = opts->ip_srcrt.dst; 454 m_tag_delete(m0, (struct m_tag *)opts); 455 return (m); 456} 457 458/* 459 * Strip out IP options, at higher level protocol in the kernel. Second 460 * argument is buffer to which options will be moved, and return value is 461 * their length. 462 * 463 * XXX should be deleted; last arg currently ignored. 464 */ 465void 466ip_stripoptions(struct mbuf *m, struct mbuf *mopt) 467{ 468 int i; 469 struct ip *ip = mtod(m, struct ip *); 470 caddr_t opts; 471 int olen; 472 473 olen = (ip->ip_hl << 2) - sizeof (struct ip); 474 opts = (caddr_t)(ip + 1); 475 i = m->m_len - (sizeof (struct ip) + olen); 476 bcopy(opts + olen, opts, (unsigned)i); 477 m->m_len -= olen; 478 if (m->m_flags & M_PKTHDR) 479 m->m_pkthdr.len -= olen; 480 ip->ip_v = IPVERSION; 481 ip->ip_hl = sizeof(struct ip) >> 2; 482} 483 484/* 485 * Insert IP options into preformed packet. Adjust IP destination as 486 * required for IP source routing, as indicated by a non-zero in_addr at the 487 * start of the options. 488 * 489 * XXX This routine assumes that the packet has no options in place. 490 */ 491struct mbuf * 492ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen) 493{ 494 struct ipoption *p = mtod(opt, struct ipoption *); 495 struct mbuf *n; 496 struct ip *ip = mtod(m, struct ip *); 497 unsigned optlen; 498 499 optlen = opt->m_len - sizeof(p->ipopt_dst); 500 if (optlen + ip->ip_len > IP_MAXPACKET) { 501 *phlen = 0; 502 return (m); /* XXX should fail */ 503 } 504 if (p->ipopt_dst.s_addr) 505 ip->ip_dst = p->ipopt_dst; 506 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) { 507 MGETHDR(n, M_DONTWAIT, MT_DATA); 508 if (n == NULL) { 509 *phlen = 0; 510 return (m); 511 } 512 M_MOVE_PKTHDR(n, m); 513 n->m_pkthdr.rcvif = NULL; 514 n->m_pkthdr.len += optlen; 515 m->m_len -= sizeof(struct ip); 516 m->m_data += sizeof(struct ip); 517 n->m_next = m; 518 m = n; 519 m->m_len = optlen + sizeof(struct ip); 520 m->m_data += max_linkhdr; 521 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 522 } else { 523 m->m_data -= optlen; 524 m->m_len += optlen; 525 m->m_pkthdr.len += optlen; 526 bcopy(ip, mtod(m, void *), sizeof(struct ip)); 527 } 528 ip = mtod(m, struct ip *); 529 bcopy(p->ipopt_list, ip + 1, optlen); 530 *phlen = sizeof(struct ip) + optlen; 531 ip->ip_v = IPVERSION; 532 ip->ip_hl = *phlen >> 2; 533 ip->ip_len += optlen; 534 return (m); 535} 536 537/* 538 * Copy options from ip to jp, omitting those not copied during 539 * fragmentation. 540 */ 541int 542ip_optcopy(struct ip *ip, struct ip *jp) 543{ 544 u_char *cp, *dp; 545 int opt, optlen, cnt; 546 547 cp = (u_char *)(ip + 1); 548 dp = (u_char *)(jp + 1); 549 cnt = (ip->ip_hl << 2) - sizeof (struct ip); 550 for (; cnt > 0; cnt -= optlen, cp += optlen) { 551 opt = cp[0]; 552 if (opt == IPOPT_EOL) 553 break; 554 if (opt == IPOPT_NOP) { 555 /* Preserve for IP mcast tunnel's LSRR alignment. */ 556 *dp++ = IPOPT_NOP; 557 optlen = 1; 558 continue; 559 } 560 561 KASSERT(cnt >= IPOPT_OLEN + sizeof(*cp), 562 ("ip_optcopy: malformed ipv4 option")); 563 optlen = cp[IPOPT_OLEN]; 564 KASSERT(optlen >= IPOPT_OLEN + sizeof(*cp) && optlen <= cnt, 565 ("ip_optcopy: malformed ipv4 option")); 566 567 /* Bogus lengths should have been caught by ip_dooptions. */ 568 if (optlen > cnt) 569 optlen = cnt; 570 if (IPOPT_COPIED(opt)) { 571 bcopy(cp, dp, optlen); 572 dp += optlen; 573 } 574 } 575 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++) 576 *dp++ = IPOPT_EOL; 577 return (optlen); 578} 579 580/* 581 * Set up IP options in pcb for insertion in output packets. Store in mbuf 582 * with pointer in pcbopt, adding pseudo-option with destination address if 583 * source routed. 584 */ 585int 586ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m) 587{ 588 int cnt, optlen; 589 u_char *cp; 590 struct mbuf **pcbopt; 591 u_char opt; 592 593 INP_WLOCK_ASSERT(inp); 594 595 pcbopt = &inp->inp_options; 596 597 /* turn off any old options */ 598 if (*pcbopt) 599 (void)m_free(*pcbopt); 600 *pcbopt = 0; 601 if (m == NULL || m->m_len == 0) { 602 /* 603 * Only turning off any previous options. 604 */ 605 if (m != NULL) 606 (void)m_free(m); 607 return (0); 608 } 609 610 if (m->m_len % sizeof(int32_t)) 611 goto bad; 612 /* 613 * IP first-hop destination address will be stored before actual 614 * options; move other options back and clear it when none present. 615 */ 616 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN]) 617 goto bad; 618 cnt = m->m_len; 619 m->m_len += sizeof(struct in_addr); 620 cp = mtod(m, u_char *) + sizeof(struct in_addr); 621 bcopy(mtod(m, void *), cp, (unsigned)cnt); 622 bzero(mtod(m, void *), sizeof(struct in_addr)); 623 624 for (; cnt > 0; cnt -= optlen, cp += optlen) { 625 opt = cp[IPOPT_OPTVAL]; 626 if (opt == IPOPT_EOL) 627 break; 628 if (opt == IPOPT_NOP) 629 optlen = 1; 630 else { 631 if (cnt < IPOPT_OLEN + sizeof(*cp)) 632 goto bad; 633 optlen = cp[IPOPT_OLEN]; 634 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) 635 goto bad; 636 } 637 switch (opt) { 638 639 default: 640 break; 641 642 case IPOPT_LSRR: 643 case IPOPT_SSRR: 644 /* 645 * User process specifies route as: 646 * 647 * ->A->B->C->D 648 * 649 * D must be our final destination (but we can't 650 * check that since we may not have connected yet). 651 * A is first hop destination, which doesn't appear 652 * in actual IP option, but is stored before the 653 * options. 654 */ 655 /* XXX-BZ PRIV_NETINET_SETHDROPTS? */ 656 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr)) 657 goto bad; 658 m->m_len -= sizeof(struct in_addr); 659 cnt -= sizeof(struct in_addr); 660 optlen -= sizeof(struct in_addr); 661 cp[IPOPT_OLEN] = optlen; 662 /* 663 * Move first hop before start of options. 664 */ 665 bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t), 666 sizeof(struct in_addr)); 667 /* 668 * Then copy rest of options back 669 * to close up the deleted entry. 670 */ 671 bcopy((&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr)), 672 &cp[IPOPT_OFFSET+1], 673 (unsigned)cnt - (IPOPT_MINOFF - 1)); 674 break; 675 } 676 } 677 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr)) 678 goto bad; 679 *pcbopt = m; 680 return (0); 681 682bad: 683 (void)m_free(m); 684 return (EINVAL); 685}
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