1/* 2 * Copyright (c) 1983, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32#include "defs.h" 33 34#ifdef __NetBSD__ 35__RCSID("$NetBSD$"); 36#elif defined(__FreeBSD__) 37__RCSID("$FreeBSD$"); 38#else 39__RCSID("$Revision: 2.26 $"); 40#ident "$Revision: 2.26 $" 41#endif 42 43static void input(struct sockaddr_in *, struct interface *, struct interface *, 44 struct rip *, int); 45static void input_route(naddr, naddr, struct rt_spare *, struct netinfo *); 46static int ck_passwd(struct interface *, struct rip *, void *, 47 naddr, struct msg_limit *); 48 49 50/* process RIP input 51 */ 52void 53read_rip(int sock, 54 struct interface *sifp) 55{ 56 struct sockaddr_in from; 57 struct interface *aifp; 58 socklen_t fromlen; 59 int cc; 60#ifdef USE_PASSIFNAME 61 static struct msg_limit bad_name; 62 struct { 63 char ifname[IFNAMSIZ]; 64 union pkt_buf pbuf; 65 } inbuf; 66#else 67 struct { 68 union pkt_buf pbuf; 69 } inbuf; 70#endif 71 72 73 for (;;) { 74 fromlen = sizeof(from); 75 cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 76 (struct sockaddr*)&from, &fromlen); 77 if (cc <= 0) { 78 if (cc < 0 && errno != EWOULDBLOCK) 79 LOGERR("recvfrom(rip)"); 80 break; 81 } 82 if (fromlen != sizeof(struct sockaddr_in)) 83 logbad(1,"impossible recvfrom(rip) fromlen=%d", 84 (int)fromlen); 85 86 /* aifp is the "authenticated" interface via which the packet 87 * arrived. In fact, it is only the interface on which 88 * the packet should have arrived based on is source 89 * address. 90 * sifp is interface associated with the socket through which 91 * the packet was received. 92 */ 93#ifdef USE_PASSIFNAME 94 if ((cc -= sizeof(inbuf.ifname)) < 0) 95 logbad(0,"missing USE_PASSIFNAME; only %d bytes", 96 cc+sizeof(inbuf.ifname)); 97 98 /* check the remote interfaces first */ 99 LIST_FOREACH(aifp, &remote_if, remote_list) { 100 if (aifp->int_addr == from.sin_addr.s_addr) 101 break; 102 } 103 if (aifp == 0) { 104 aifp = ifwithname(inbuf.ifname, 0); 105 if (aifp == 0) { 106 msglim(&bad_name, from.sin_addr.s_addr, 107 "impossible interface name %.*s", 108 IFNAMSIZ, inbuf.ifname); 109 } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 110 && aifp->int_dstaddr!=from.sin_addr.s_addr) 111 || (!(aifp->int_if_flags & IFF_POINTOPOINT) 112 && !on_net(from.sin_addr.s_addr, 113 aifp->int_net, 114 aifp->int_mask))) { 115 /* If it came via the wrong interface, do not 116 * trust it. 117 */ 118 aifp = 0; 119 } 120 } 121#else 122 aifp = iflookup(from.sin_addr.s_addr); 123#endif 124 if (sifp == 0) 125 sifp = aifp; 126 127 input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 128 } 129} 130 131 132/* Process a RIP packet 133 */ 134static void 135input(struct sockaddr_in *from, /* received from this IP address */ 136 struct interface *sifp, /* interface of incoming socket */ 137 struct interface *aifp, /* "authenticated" interface */ 138 struct rip *rip, 139 int cc) 140{ 141# define FROM_NADDR from->sin_addr.s_addr 142 static struct msg_limit use_auth, bad_len, bad_mask; 143 static struct msg_limit unk_router, bad_router, bad_nhop; 144 145 struct rt_entry *rt; 146 struct rt_spare new; 147 struct netinfo *n, *lim; 148 struct interface *ifp1; 149 naddr gate, mask, v1_mask, dst, ddst_h = 0; 150 struct auth *ap; 151 struct tgate *tg = 0; 152 struct tgate_net *tn; 153 int i, j; 154 155 /* Notice when we hear from a remote gateway 156 */ 157 if (aifp != 0 158 && (aifp->int_state & IS_REMOTE)) 159 aifp->int_act_time = now.tv_sec; 160 161 trace_rip("Recv", "from", from, sifp, rip, cc); 162 163 if (sifp == 0) { 164 trace_pkt(" discard a request from an indirect router" 165 " (possibly an attack)"); 166 return; 167 } 168 169 if (rip->rip_vers == 0) { 170 msglim(&bad_router, FROM_NADDR, 171 "RIP version 0, cmd %d, packet received from %s", 172 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 173 return; 174 } else if (rip->rip_vers > RIPv2) { 175 rip->rip_vers = RIPv2; 176 } 177 if (cc > (int)OVER_MAXPACKETSIZE) { 178 msglim(&bad_router, FROM_NADDR, 179 "packet at least %d bytes too long received from %s", 180 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 181 return; 182 } 183 184 n = rip->rip_nets; 185 lim = (struct netinfo *)((char*)rip + cc); 186 187 /* Notice authentication. 188 * As required by section 4.2 in RFC 1723, discard authenticated 189 * RIPv2 messages, but only if configured for that silliness. 190 * 191 * RIPv2 authentication is lame. Why authenticate queries? 192 * Why should a RIPv2 implementation with authentication disabled 193 * not be able to listen to RIPv2 packets with authentication, while 194 * RIPv1 systems will listen? Crazy! 195 */ 196 if (!auth_ok 197 && rip->rip_vers == RIPv2 198 && n < lim && n->n_family == RIP_AF_AUTH) { 199 msglim(&use_auth, FROM_NADDR, 200 "RIPv2 message with authentication from %s discarded", 201 naddr_ntoa(FROM_NADDR)); 202 return; 203 } 204 205 switch (rip->rip_cmd) { 206 case RIPCMD_REQUEST: 207 /* For mere requests, be a little sloppy about the source 208 */ 209 if (aifp == 0) 210 aifp = sifp; 211 212 /* Are we talking to ourself or a remote gateway? 213 */ 214 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 215 if (ifp1) { 216 if (ifp1->int_state & IS_REMOTE) { 217 /* remote gateway */ 218 aifp = ifp1; 219 if (check_remote(aifp)) { 220 aifp->int_act_time = now.tv_sec; 221 (void)if_ok(aifp, "remote "); 222 } 223 } else if (from->sin_port == htons(RIP_PORT)) { 224 trace_pkt(" discard our own RIP request"); 225 return; 226 } 227 } 228 229 /* did the request come from a router? 230 */ 231 if (from->sin_port == htons(RIP_PORT)) { 232 /* yes, ignore the request if RIP is off so that 233 * the router does not depend on us. 234 */ 235 if (rip_sock < 0 236 || (aifp != 0 237 && IS_RIP_OUT_OFF(aifp->int_state))) { 238 trace_pkt(" discard request while RIP off"); 239 return; 240 } 241 } 242 243 /* According to RFC 1723, we should ignore unauthenticated 244 * queries. That is too silly to bother with. Sheesh! 245 * Are forwarding tables supposed to be secret, when 246 * a bad guy can infer them with test traffic? When RIP 247 * is still the most common router-discovery protocol 248 * and so hosts need to send queries that will be answered? 249 * What about `rtquery`? 250 * Maybe on firewalls you'd care, but not enough to 251 * give up the diagnostic facilities of remote probing. 252 */ 253 254 if (n >= lim) { 255 msglim(&bad_len, FROM_NADDR, "empty request from %s", 256 naddr_ntoa(FROM_NADDR)); 257 return; 258 } 259 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 260 msglim(&bad_len, FROM_NADDR, 261 "request of bad length (%d) from %s", 262 cc, naddr_ntoa(FROM_NADDR)); 263 } 264 265 if (rip->rip_vers == RIPv2 266 && (aifp == 0 || (aifp->int_state & IS_NO_RIPV1_OUT))) { 267 v12buf.buf->rip_vers = RIPv2; 268 /* If we have a secret but it is a cleartext secret, 269 * do not disclose our secret unless the other guy 270 * already knows it. 271 */ 272 ap = find_auth(aifp); 273 if (ap != 0 && ap->type == RIP_AUTH_PW 274 && n->n_family == RIP_AF_AUTH 275 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 276 ap = 0; 277 } else { 278 v12buf.buf->rip_vers = RIPv1; 279 ap = 0; 280 } 281 clr_ws_buf(&v12buf, ap); 282 283 do { 284 n->n_metric = ntohl(n->n_metric); 285 286 /* A single entry with family RIP_AF_UNSPEC and 287 * metric HOPCNT_INFINITY means "all routes". 288 * We respond to routers only if we are acting 289 * as a supplier, or to anyone other than a router 290 * (i.e. a query). 291 */ 292 if (n->n_family == RIP_AF_UNSPEC 293 && n->n_metric == HOPCNT_INFINITY) { 294 /* Answer a query from a utility program 295 * with all we know. 296 */ 297 if (aifp == NULL) { 298 trace_pkt("ignore remote query"); 299 return; 300 } 301 if (from->sin_port != htons(RIP_PORT)) { 302 supply(from, aifp, OUT_QUERY, 0, 303 rip->rip_vers, ap != 0); 304 return; 305 } 306 307 /* A router trying to prime its tables. 308 * Filter the answer in the about same way 309 * broadcasts are filtered. 310 * 311 * Only answer a router if we are a supplier 312 * to keep an unwary host that is just starting 313 * from picking us as a router. 314 */ 315 if (aifp == 0) { 316 trace_pkt("ignore distant router"); 317 return; 318 } 319 if (!supplier 320 || IS_RIP_OFF(aifp->int_state)) { 321 trace_pkt("ignore; not supplying"); 322 return; 323 } 324 325 /* Do not answer a RIPv1 router if 326 * we are sending RIPv2. But do offer 327 * poor man's router discovery. 328 */ 329 if ((aifp->int_state & IS_NO_RIPV1_OUT) 330 && rip->rip_vers == RIPv1) { 331 if (!(aifp->int_state & IS_PM_RDISC)) { 332 trace_pkt("ignore; sending RIPv2"); 333 return; 334 } 335 336 v12buf.n->n_family = RIP_AF_INET; 337 v12buf.n->n_dst = RIP_DEFAULT; 338 i = aifp->int_d_metric; 339 if (0 != (rt = rtget(RIP_DEFAULT, 0))) { 340 j = (rt->rt_metric 341 +aifp->int_metric 342 +aifp->int_adj_outmetric 343 +1); 344 if (i > j) 345 i = j; 346 } 347 v12buf.n->n_metric = htonl(i); 348 v12buf.n++; 349 break; 350 } 351 352 /* Respond with RIPv1 instead of RIPv2 if 353 * that is what we are broadcasting on the 354 * interface to keep the remote router from 355 * getting the wrong initial idea of the 356 * routes we send. 357 */ 358 supply(from, aifp, OUT_UNICAST, 0, 359 (aifp->int_state & IS_NO_RIPV1_OUT) 360 ? RIPv2 : RIPv1, 361 ap != 0); 362 return; 363 } 364 365 /* Ignore authentication */ 366 if (n->n_family == RIP_AF_AUTH) 367 continue; 368 369 if (n->n_family != RIP_AF_INET) { 370 msglim(&bad_router, FROM_NADDR, 371 "request from %s for unsupported" 372 " (af %d) %s", 373 naddr_ntoa(FROM_NADDR), 374 ntohs(n->n_family), 375 naddr_ntoa(n->n_dst)); 376 return; 377 } 378 379 /* We are being asked about a specific destination. 380 */ 381 dst = n->n_dst; 382 if (!check_dst(dst)) { 383 msglim(&bad_router, FROM_NADDR, 384 "bad queried destination %s from %s", 385 naddr_ntoa(dst), 386 naddr_ntoa(FROM_NADDR)); 387 return; 388 } 389 390 /* decide what mask was intended */ 391 if (rip->rip_vers == RIPv1 392 || 0 == (mask = ntohl(n->n_mask)) 393 || 0 != (ntohl(dst) & ~mask)) 394 mask = ripv1_mask_host(dst, aifp); 395 396 /* try to find the answer */ 397 rt = rtget(dst, mask); 398 if (!rt && dst != RIP_DEFAULT) 399 rt = rtfind(n->n_dst); 400 401 if (v12buf.buf->rip_vers != RIPv1) 402 v12buf.n->n_mask = mask; 403 if (rt == 0) { 404 /* we do not have the answer */ 405 v12buf.n->n_metric = HOPCNT_INFINITY; 406 } else { 407 /* we have the answer, so compute the 408 * right metric and next hop. 409 */ 410 v12buf.n->n_family = RIP_AF_INET; 411 v12buf.n->n_dst = dst; 412 j = rt->rt_metric+1; 413 if (!aifp) 414 ++j; 415 else 416 j += (aifp->int_metric 417 + aifp->int_adj_outmetric); 418 if (j < HOPCNT_INFINITY) 419 v12buf.n->n_metric = j; 420 else 421 v12buf.n->n_metric = HOPCNT_INFINITY; 422 if (v12buf.buf->rip_vers != RIPv1) { 423 v12buf.n->n_tag = rt->rt_tag; 424 v12buf.n->n_mask = mask; 425 if (aifp != 0 426 && on_net(rt->rt_gate, 427 aifp->int_net, 428 aifp->int_mask) 429 && rt->rt_gate != aifp->int_addr) 430 v12buf.n->n_nhop = rt->rt_gate; 431 } 432 } 433 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 434 435 /* Stop paying attention if we fill the output buffer. 436 */ 437 if (++v12buf.n >= v12buf.lim) 438 break; 439 } while (++n < lim); 440 441 /* Send the answer about specific routes. 442 */ 443 if (ap != 0 && ap->type == RIP_AUTH_MD5) 444 end_md5_auth(&v12buf, ap); 445 446 if (from->sin_port != htons(RIP_PORT)) { 447 /* query */ 448 (void)output(OUT_QUERY, from, aifp, 449 v12buf.buf, 450 ((char *)v12buf.n - (char*)v12buf.buf)); 451 } else if (supplier) { 452 (void)output(OUT_UNICAST, from, aifp, 453 v12buf.buf, 454 ((char *)v12buf.n - (char*)v12buf.buf)); 455 } else { 456 /* Only answer a router if we are a supplier 457 * to keep an unwary host that is just starting 458 * from picking us an a router. 459 */ 460 ; 461 } 462 return; 463 464 case RIPCMD_TRACEON: 465 case RIPCMD_TRACEOFF: 466 /* Notice that trace messages are turned off for all possible 467 * abuse if _PATH_TRACE is undefined in pathnames.h. 468 * Notice also that because of the way the trace file is 469 * handled in trace.c, no abuse is plausible even if 470 * _PATH_TRACE_ is defined. 471 * 472 * First verify message came from a privileged port. */ 473 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 474 msglog("trace command from untrusted port on %s", 475 naddr_ntoa(FROM_NADDR)); 476 return; 477 } 478 if (aifp == 0) { 479 msglog("trace command from unknown router %s", 480 naddr_ntoa(FROM_NADDR)); 481 return; 482 } 483 if (rip->rip_cmd == RIPCMD_TRACEON) { 484 rip->rip_tracefile[cc-4] = '\0'; 485 set_tracefile((char*)rip->rip_tracefile, 486 "trace command: %s\n", 0); 487 } else { 488 trace_off("tracing turned off by %s", 489 naddr_ntoa(FROM_NADDR)); 490 } 491 return; 492 493 case RIPCMD_RESPONSE: 494 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 495 msglim(&bad_len, FROM_NADDR, 496 "response of bad length (%d) from %s", 497 cc, naddr_ntoa(FROM_NADDR)); 498 } 499 500 /* verify message came from a router */ 501 if (from->sin_port != ntohs(RIP_PORT)) { 502 msglim(&bad_router, FROM_NADDR, 503 " discard RIP response from unknown port" 504 " %d on %s", 505 ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); 506 return; 507 } 508 509 if (rip_sock < 0) { 510 trace_pkt(" discard response while RIP off"); 511 return; 512 } 513 514 /* Are we talking to ourself or a remote gateway? 515 */ 516 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 517 if (ifp1) { 518 if (ifp1->int_state & IS_REMOTE) { 519 /* remote gateway */ 520 aifp = ifp1; 521 if (check_remote(aifp)) { 522 aifp->int_act_time = now.tv_sec; 523 (void)if_ok(aifp, "remote "); 524 } 525 } else { 526 trace_pkt(" discard our own RIP response"); 527 return; 528 } 529 } 530 531 /* Accept routing packets from routers directly connected 532 * via broadcast or point-to-point networks, and from 533 * those listed in /etc/gateways. 534 */ 535 if (aifp == 0) { 536 msglim(&unk_router, FROM_NADDR, 537 " discard response from %s" 538 " via unexpected interface", 539 naddr_ntoa(FROM_NADDR)); 540 return; 541 } 542 if (IS_RIP_IN_OFF(aifp->int_state)) { 543 trace_pkt(" discard RIPv%d response" 544 " via disabled interface %s", 545 rip->rip_vers, aifp->int_name); 546 return; 547 } 548 549 if (n >= lim) { 550 msglim(&bad_len, FROM_NADDR, "empty response from %s", 551 naddr_ntoa(FROM_NADDR)); 552 return; 553 } 554 555 if (((aifp->int_state & IS_NO_RIPV1_IN) 556 && rip->rip_vers == RIPv1) 557 || ((aifp->int_state & IS_NO_RIPV2_IN) 558 && rip->rip_vers != RIPv1)) { 559 trace_pkt(" discard RIPv%d response", 560 rip->rip_vers); 561 return; 562 } 563 564 /* Ignore routes via dead interface. 565 */ 566 if (aifp->int_state & IS_BROKE) { 567 trace_pkt("discard response via broken interface %s", 568 aifp->int_name); 569 return; 570 } 571 572 /* If the interface cares, ignore bad routers. 573 * Trace but do not log this problem, because where it 574 * happens, it happens frequently. 575 */ 576 if (aifp->int_state & IS_DISTRUST) { 577 tg = tgates; 578 while (tg->tgate_addr != FROM_NADDR) { 579 tg = tg->tgate_next; 580 if (tg == 0) { 581 trace_pkt(" discard RIP response" 582 " from untrusted router %s", 583 naddr_ntoa(FROM_NADDR)); 584 return; 585 } 586 } 587 } 588 589 /* Authenticate the packet if we have a secret. 590 * If we do not have any secrets, ignore the error in 591 * RFC 1723 and accept it regardless. 592 */ 593 if (aifp->int_auth[0].type != RIP_AUTH_NONE 594 && rip->rip_vers != RIPv1 595 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 596 return; 597 598 do { 599 if (n->n_family == RIP_AF_AUTH) 600 continue; 601 602 n->n_metric = ntohl(n->n_metric); 603 dst = n->n_dst; 604 if (n->n_family != RIP_AF_INET 605 && (n->n_family != RIP_AF_UNSPEC 606 || dst != RIP_DEFAULT)) { 607 msglim(&bad_router, FROM_NADDR, 608 "route from %s to unsupported" 609 " address family=%d destination=%s", 610 naddr_ntoa(FROM_NADDR), 611 n->n_family, 612 naddr_ntoa(dst)); 613 continue; 614 } 615 if (!check_dst(dst)) { 616 msglim(&bad_router, FROM_NADDR, 617 "bad destination %s from %s", 618 naddr_ntoa(dst), 619 naddr_ntoa(FROM_NADDR)); 620 return; 621 } 622 if (n->n_metric == 0 623 || n->n_metric > HOPCNT_INFINITY) { 624 msglim(&bad_router, FROM_NADDR, 625 "bad metric %d from %s" 626 " for destination %s", 627 n->n_metric, 628 naddr_ntoa(FROM_NADDR), 629 naddr_ntoa(dst)); 630 return; 631 } 632 633 /* Notice the next-hop. 634 */ 635 gate = FROM_NADDR; 636 if (n->n_nhop != 0) { 637 if (rip->rip_vers == RIPv1) { 638 n->n_nhop = 0; 639 } else { 640 /* Use it only if it is valid. */ 641 if (on_net(n->n_nhop, 642 aifp->int_net, aifp->int_mask) 643 && check_dst(n->n_nhop)) { 644 gate = n->n_nhop; 645 } else { 646 msglim(&bad_nhop, FROM_NADDR, 647 "router %s to %s" 648 " has bad next hop %s", 649 naddr_ntoa(FROM_NADDR), 650 naddr_ntoa(dst), 651 naddr_ntoa(n->n_nhop)); 652 n->n_nhop = 0; 653 } 654 } 655 } 656 657 if (rip->rip_vers == RIPv1 658 || 0 == (mask = ntohl(n->n_mask))) { 659 mask = ripv1_mask_host(dst,aifp); 660 } else if ((ntohl(dst) & ~mask) != 0) { 661 msglim(&bad_mask, FROM_NADDR, 662 "router %s sent bad netmask" 663 " %#lx with %s", 664 naddr_ntoa(FROM_NADDR), 665 (u_long)mask, 666 naddr_ntoa(dst)); 667 continue; 668 } 669 if (rip->rip_vers == RIPv1) 670 n->n_tag = 0; 671 672 /* Adjust metric according to incoming interface.. 673 */ 674 n->n_metric += (aifp->int_metric 675 + aifp->int_adj_inmetric); 676 if (n->n_metric > HOPCNT_INFINITY) 677 n->n_metric = HOPCNT_INFINITY; 678 679 /* Should we trust this route from this router? */ 680 if (tg && (tn = tg->tgate_nets)->mask != 0) { 681 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 682 if (on_net(dst, tn->net, tn->mask) 683 && tn->mask <= mask) 684 break; 685 } 686 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 687 trace_pkt(" ignored unauthorized %s", 688 addrname(dst,mask,0)); 689 continue; 690 } 691 } 692 693 /* Recognize and ignore a default route we faked 694 * which is being sent back to us by a machine with 695 * broken split-horizon. 696 * Be a little more paranoid than that, and reject 697 * default routes with the same metric we advertised. 698 */ 699 if (aifp->int_d_metric != 0 700 && dst == RIP_DEFAULT 701 && (int)n->n_metric >= aifp->int_d_metric) 702 continue; 703 704 /* We can receive aggregated RIPv2 routes that must 705 * be broken down before they are transmitted by 706 * RIPv1 via an interface on a subnet. 707 * We might also receive the same routes aggregated 708 * via other RIPv2 interfaces. 709 * This could cause duplicate routes to be sent on 710 * the RIPv1 interfaces. "Longest matching variable 711 * length netmasks" lets RIPv2 listeners understand, 712 * but breaking down the aggregated routes for RIPv1 713 * listeners can produce duplicate routes. 714 * 715 * Breaking down aggregated routes here bloats 716 * the daemon table, but does not hurt the kernel 717 * table, since routes are always aggregated for 718 * the kernel. 719 * 720 * Notice that this does not break down network 721 * routes corresponding to subnets. This is part 722 * of the defense against RS_NET_SYN. 723 */ 724 if (have_ripv1_out 725 && (((rt = rtget(dst,mask)) == 0 726 || !(rt->rt_state & RS_NET_SYN))) 727 && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 728 ddst_h = v1_mask & -v1_mask; 729 i = (v1_mask & ~mask)/ddst_h; 730 if (i >= 511) { 731 /* Punt if we would have to generate 732 * an unreasonable number of routes. 733 */ 734 if (TRACECONTENTS) 735 trace_misc("accept %s-->%s as 1" 736 " instead of %d routes", 737 addrname(dst,mask,0), 738 naddr_ntoa(FROM_NADDR), 739 i+1); 740 i = 0; 741 } else { 742 mask = v1_mask; 743 } 744 } else { 745 i = 0; 746 } 747 748 new.rts_gate = gate; 749 new.rts_router = FROM_NADDR; 750 new.rts_metric = n->n_metric; 751 new.rts_tag = n->n_tag; 752 new.rts_time = now.tv_sec; 753 new.rts_ifp = aifp; 754 new.rts_de_ag = i; 755 j = 0; 756 for (;;) { 757 input_route(dst, mask, &new, n); 758 if (++j > i) 759 break; 760 dst = htonl(ntohl(dst) + ddst_h); 761 } 762 } while (++n < lim); 763 break; 764 } 765#undef FROM_NADDR 766} 767 768 769/* Process a single input route. 770 */ 771static void 772input_route(naddr dst, /* network order */ 773 naddr mask, 774 struct rt_spare *new, 775 struct netinfo *n) 776{ 777 int i; 778 struct rt_entry *rt; 779 struct rt_spare *rts, *rts0; 780 struct interface *ifp1; 781 782 783 /* See if the other guy is telling us to send our packets to him. 784 * Sometimes network routes arrive over a point-to-point link for 785 * the network containing the address(es) of the link. 786 * 787 * If our interface is broken, switch to using the other guy. 788 */ 789 ifp1 = ifwithaddr(dst, 1, 1); 790 if (ifp1 != 0 791 && (!(ifp1->int_state & IS_BROKE) 792 || (ifp1->int_state & IS_PASSIVE))) 793 return; 794 795 /* Look for the route in our table. 796 */ 797 rt = rtget(dst, mask); 798 799 /* Consider adding the route if we do not already have it. 800 */ 801 if (rt == 0) { 802 /* Ignore unknown routes being poisoned. 803 */ 804 if (new->rts_metric == HOPCNT_INFINITY) 805 return; 806 807 /* Ignore the route if it points to us */ 808 if (n->n_nhop != 0 809 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 810 return; 811 812 /* If something has not gone crazy and tried to fill 813 * our memory, accept the new route. 814 */ 815 if (total_routes < MAX_ROUTES) 816 rtadd(dst, mask, 0, new); 817 return; 818 } 819 820 /* We already know about the route. Consider this update. 821 * 822 * If (rt->rt_state & RS_NET_SYN), then this route 823 * is the same as a network route we have inferred 824 * for subnets we know, in order to tell RIPv1 routers 825 * about the subnets. 826 * 827 * It is impossible to tell if the route is coming 828 * from a distant RIPv2 router with the standard 829 * netmask because that router knows about the entire 830 * network, or if it is a round-about echo of a 831 * synthetic, RIPv1 network route of our own. 832 * The worst is that both kinds of routes might be 833 * received, and the bad one might have the smaller 834 * metric. Partly solve this problem by never 835 * aggregating into such a route. Also keep it 836 * around as long as the interface exists. 837 */ 838 839 rts0 = rt->rt_spares; 840 for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 841 if (rts->rts_router == new->rts_router) 842 break; 843 /* Note the worst slot to reuse, 844 * other than the current slot. 845 */ 846 if (rts0 == rt->rt_spares 847 || BETTER_LINK(rt, rts0, rts)) 848 rts0 = rts; 849 } 850 if (i != 0) { 851 /* Found a route from the router already in the table. 852 */ 853 854 /* If the new route is a route broken down from an 855 * aggregated route, and if the previous route is either 856 * not a broken down route or was broken down from a finer 857 * netmask, and if the previous route is current, 858 * then forget this one. 859 */ 860 if (new->rts_de_ag > rts->rts_de_ag 861 && now_stale <= rts->rts_time) 862 return; 863 864 /* Keep poisoned routes around only long enough to pass 865 * the poison on. Use a new timestamp for good routes. 866 */ 867 if (rts->rts_metric == HOPCNT_INFINITY 868 && new->rts_metric == HOPCNT_INFINITY) 869 new->rts_time = rts->rts_time; 870 871 /* If this is an update for the router we currently prefer, 872 * then note it. 873 */ 874 if (i == NUM_SPARES) { 875 rtchange(rt, rt->rt_state, new, 0); 876 /* If the route got worse, check for something better. 877 */ 878 if (new->rts_metric > rts->rts_metric) 879 rtswitch(rt, 0); 880 return; 881 } 882 883 /* This is an update for a spare route. 884 * Finished if the route is unchanged. 885 */ 886 if (rts->rts_gate == new->rts_gate 887 && rts->rts_metric == new->rts_metric 888 && rts->rts_tag == new->rts_tag) { 889 trace_upslot(rt, rts, new); 890 *rts = *new; 891 return; 892 } 893 /* Forget it if it has gone bad. 894 */ 895 if (new->rts_metric == HOPCNT_INFINITY) { 896 rts_delete(rt, rts); 897 return; 898 } 899 900 } else { 901 /* The update is for a route we know about, 902 * but not from a familiar router. 903 * 904 * Ignore the route if it points to us. 905 */ 906 if (n->n_nhop != 0 907 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 908 return; 909 910 /* the loop above set rts0=worst spare */ 911 rts = rts0; 912 913 /* Save the route as a spare only if it has 914 * a better metric than our worst spare. 915 * This also ignores poisoned routes (those 916 * received with metric HOPCNT_INFINITY). 917 */ 918 if (new->rts_metric >= rts->rts_metric) 919 return; 920 } 921 922 trace_upslot(rt, rts, new); 923 *rts = *new; 924 925 /* try to switch to a better route */ 926 rtswitch(rt, rts); 927} 928 929 930static int /* 0 if bad */ 931ck_passwd(struct interface *aifp, 932 struct rip *rip, 933 void *lim, 934 naddr from, 935 struct msg_limit *use_authp) 936{ 937# define NA (rip->rip_auths) 938 struct netauth *na2; 939 struct auth *ap; 940 MD5_CTX md5_ctx; 941 u_char hash[RIP_AUTH_PW_LEN]; 942 int i, len; 943 944 assert(aifp != NULL); 945 if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 946 msglim(use_authp, from, "missing password from %s", 947 naddr_ntoa(from)); 948 return 0; 949 } 950 951 /* accept any current (+/- 24 hours) password 952 */ 953 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 954 if (ap->type != NA->a_type 955 || (u_long)ap->start > (u_long)clk.tv_sec+DAY 956 || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 957 continue; 958 959 if (NA->a_type == RIP_AUTH_PW) { 960 if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 961 return 1; 962 963 } else { 964 /* accept MD5 secret with the right key ID 965 */ 966 if (NA->au.a_md5.md5_keyid != ap->keyid) 967 continue; 968 969 len = ntohs(NA->au.a_md5.md5_pkt_len); 970 if ((len-sizeof(*rip)) % sizeof(*NA) != 0 971 || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 972 msglim(use_authp, from, 973 "wrong MD5 RIPv2 packet length of %d" 974 " instead of %d from %s", 975 len, (int)((char *)lim-(char *)rip 976 -sizeof(*NA)), 977 naddr_ntoa(from)); 978 return 0; 979 } 980 na2 = (struct netauth *)((char *)rip+len); 981 982 /* Given a good hash value, these are not security 983 * problems so be generous and accept the routes, 984 * after complaining. 985 */ 986 if (TRACEPACKETS) { 987 if (NA->au.a_md5.md5_auth_len 988 != RIP_AUTH_MD5_HASH_LEN) 989 msglim(use_authp, from, 990 "unknown MD5 RIPv2 auth len %#x" 991 " instead of %#x from %s", 992 NA->au.a_md5.md5_auth_len, 993 (unsigned)RIP_AUTH_MD5_HASH_LEN, 994 naddr_ntoa(from)); 995 if (na2->a_family != RIP_AF_AUTH) 996 msglim(use_authp, from, 997 "unknown MD5 RIPv2 family %#x" 998 " instead of %#x from %s", 999 na2->a_family, RIP_AF_AUTH, 1000 naddr_ntoa(from)); 1001 if (na2->a_type != ntohs(1)) 1002 msglim(use_authp, from, 1003 "MD5 RIPv2 hash has %#x" 1004 " instead of %#x from %s", 1005 na2->a_type, ntohs(1), 1006 naddr_ntoa(from)); 1007 } 1008 1009 MD5Init(&md5_ctx); 1010 MD5Update(&md5_ctx, (u_char *)rip, 1011 len + RIP_AUTH_MD5_HASH_XTRA); 1012 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN); 1013 MD5Final(hash, &md5_ctx); 1014 if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 1015 return 1; 1016 } 1017 } 1018 1019 msglim(use_authp, from, "bad password from %s", 1020 naddr_ntoa(from)); 1021 return 0; 1022#undef NA 1023} 1024