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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgment: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD: src/sbin/routed/input.c,v 1.7.2.1 2001/08/01 09:01:45 obrien Exp $ 34 * $DragonFly: src/sbin/routed/input.c,v 1.4 2004/12/18 21:43:40 swildner Exp $ 35 */ 36 37 #include "defs.h" 38 39 #if !defined(sgi) && !defined(__NetBSD__) 40 static char sccsid[] __attribute__((unused)) = "@(#)input.c 8.1 (Berkeley) 6/5/93"; 41 #elif defined(__NetBSD__) 42 #include <sys/cdefs.h> 43 __RCSID("$NetBSD$"); 44 #endif 45 #ident "$FreeBSD: src/sbin/routed/input.c,v 1.7.2.1 2001/08/01 09:01:45 obrien Exp $" 46 47 static void input(struct sockaddr_in *, struct interface *, struct interface *, 48 struct rip *, int); 49 static void input_route(naddr, naddr, struct rt_spare *, struct netinfo *); 50 static int ck_passwd(struct interface *, struct rip *, void *, 51 naddr, struct msg_limit *); 52 53 54 /* process RIP input 55 */ 56 void 57 read_rip(int sock, 58 struct interface *sifp) 59 { 60 struct sockaddr_in from; 61 struct interface *aifp; 62 int fromlen, cc; 63 #ifdef USE_PASSIFNAME 64 static struct msg_limit bad_name; 65 struct { 66 char ifname[IFNAMSIZ]; 67 union pkt_buf pbuf; 68 } inbuf; 69 #else 70 struct { 71 union pkt_buf pbuf; 72 } inbuf; 73 #endif 74 75 76 for (;;) { 77 fromlen = sizeof(from); 78 cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 79 (struct sockaddr*)&from, &fromlen); 80 if (cc <= 0) { 81 if (cc < 0 && errno != EWOULDBLOCK) 82 LOGERR("recvfrom(rip)"); 83 break; 84 } 85 if (fromlen != sizeof(struct sockaddr_in)) 86 logbad(1,"impossible recvfrom(rip) fromlen=%d", 87 fromlen); 88 89 /* aifp is the "authenticated" interface via which the packet 90 * arrived. In fact, it is only the interface on which 91 * the packet should have arrived based on is source 92 * address. 93 * sifp is interface associated with the socket through which 94 * the packet was received. 95 */ 96 #ifdef USE_PASSIFNAME 97 if ((cc -= sizeof(inbuf.ifname)) < 0) 98 logbad(0,"missing USE_PASSIFNAME; only %d bytes", 99 cc+sizeof(inbuf.ifname)); 100 101 /* check the remote interfaces first */ 102 for (aifp = remote_if; aifp; aifp = aifp->int_rlink) { 103 if (aifp->int_addr == from.sin_addr.s_addr) 104 break; 105 } 106 if (aifp == 0) { 107 aifp = ifwithname(inbuf.ifname, 0); 108 if (aifp == 0) { 109 msglim(&bad_name, from.sin_addr.s_addr, 110 "impossible interface name %.*s", 111 IFNAMSIZ, inbuf.ifname); 112 } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 113 && aifp->int_dstaddr!=from.sin_addr.s_addr) 114 || (!(aifp->int_if_flags & IFF_POINTOPOINT) 115 && !on_net(from.sin_addr.s_addr, 116 aifp->int_net, 117 aifp->int_mask))) { 118 /* If it came via the wrong interface, do not 119 * trust it. 120 */ 121 aifp = 0; 122 } 123 } 124 #else 125 aifp = iflookup(from.sin_addr.s_addr); 126 #endif 127 if (sifp == 0) 128 sifp = aifp; 129 130 input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 131 } 132 } 133 134 135 /* Process a RIP packet 136 */ 137 static void 138 input(struct sockaddr_in *from, /* received from this IP address */ 139 struct interface *sifp, /* interface of incoming socket */ 140 struct interface *aifp, /* "authenticated" interface */ 141 struct rip *rip, 142 int cc) 143 { 144 # define FROM_NADDR from->sin_addr.s_addr 145 static struct msg_limit use_auth, bad_len, bad_mask; 146 static struct msg_limit unk_router, bad_router, bad_nhop; 147 148 struct rt_entry *rt; 149 struct rt_spare new; 150 struct netinfo *n, *lim; 151 struct interface *ifp1; 152 naddr gate, mask, v1_mask, dst, ddst_h = 0; 153 struct auth *ap; 154 struct tgate *tg = 0; 155 struct tgate_net *tn; 156 int i, j; 157 158 /* Notice when we hear from a remote gateway 159 */ 160 if (aifp != 0 161 && (aifp->int_state & IS_REMOTE)) 162 aifp->int_act_time = now.tv_sec; 163 164 trace_rip("Recv", "from", from, sifp, rip, cc); 165 166 if (rip->rip_vers == 0) { 167 msglim(&bad_router, FROM_NADDR, 168 "RIP version 0, cmd %d, packet received from %s", 169 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 170 return; 171 } else if (rip->rip_vers > RIPv2) { 172 rip->rip_vers = RIPv2; 173 } 174 if (cc > (int)OVER_MAXPACKETSIZE) { 175 msglim(&bad_router, FROM_NADDR, 176 "packet at least %d bytes too long received from %s", 177 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 178 return; 179 } 180 181 n = rip->rip_nets; 182 lim = (struct netinfo *)((char*)rip + cc); 183 184 /* Notice authentication. 185 * As required by section 4.2 in RFC 1723, discard authenticated 186 * RIPv2 messages, but only if configured for that silliness. 187 * 188 * RIPv2 authentication is lame. Why authenticate queries? 189 * Why should a RIPv2 implementation with authentication disabled 190 * not be able to listen to RIPv2 packets with authentication, while 191 * RIPv1 systems will listen? Crazy! 192 */ 193 if (!auth_ok 194 && rip->rip_vers == RIPv2 195 && n < lim && n->n_family == RIP_AF_AUTH) { 196 msglim(&use_auth, FROM_NADDR, 197 "RIPv2 message with authentication from %s discarded", 198 naddr_ntoa(FROM_NADDR)); 199 return; 200 } 201 202 switch (rip->rip_cmd) { 203 case RIPCMD_REQUEST: 204 /* For mere requests, be a little sloppy about the source 205 */ 206 if (aifp == 0) 207 aifp = sifp; 208 209 /* Are we talking to ourself or a remote gateway? 210 */ 211 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 212 if (ifp1) { 213 if (ifp1->int_state & IS_REMOTE) { 214 /* remote gateway */ 215 aifp = ifp1; 216 if (check_remote(aifp)) { 217 aifp->int_act_time = now.tv_sec; 218 if_ok(aifp, "remote "); 219 } 220 } else if (from->sin_port == htons(RIP_PORT)) { 221 trace_pkt(" discard our own RIP request"); 222 return; 223 } 224 } 225 226 /* did the request come from a router? 227 */ 228 if (from->sin_port == htons(RIP_PORT)) { 229 /* yes, ignore the request if RIP is off so that 230 * the router does not depend on us. 231 */ 232 if (rip_sock < 0 233 || (aifp != 0 234 && IS_RIP_OUT_OFF(aifp->int_state))) { 235 trace_pkt(" discard request while RIP off"); 236 return; 237 } 238 } 239 240 /* According to RFC 1723, we should ignore unauthenticated 241 * queries. That is too silly to bother with. Sheesh! 242 * Are forwarding tables supposed to be secret, when 243 * a bad guy can infer them with test traffic? When RIP 244 * is still the most common router-discovery protocol 245 * and so hosts need to send queries that will be answered? 246 * What about `rtquery`? 247 * Maybe on firewalls you'd care, but not enough to 248 * give up the diagnostic facilities of remote probing. 249 */ 250 251 if (n >= lim) { 252 msglim(&bad_len, FROM_NADDR, "empty request from %s", 253 naddr_ntoa(FROM_NADDR)); 254 return; 255 } 256 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 257 msglim(&bad_len, FROM_NADDR, 258 "request of bad length (%d) from %s", 259 cc, naddr_ntoa(FROM_NADDR)); 260 } 261 262 if (rip->rip_vers == RIPv2 263 && (aifp == 0 || (aifp->int_state & IS_NO_RIPV1_OUT))) { 264 v12buf.buf->rip_vers = RIPv2; 265 /* If we have a secret but it is a cleartext secret, 266 * do not disclose our secret unless the other guy 267 * already knows it. 268 */ 269 ap = find_auth(aifp); 270 if (ap != 0 && ap->type == RIP_AUTH_PW 271 && n->n_family == RIP_AF_AUTH 272 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 273 ap = 0; 274 } else { 275 v12buf.buf->rip_vers = RIPv1; 276 ap = 0; 277 } 278 clr_ws_buf(&v12buf, ap); 279 280 do { 281 n->n_metric = ntohl(n->n_metric); 282 283 /* A single entry with family RIP_AF_UNSPEC and 284 * metric HOPCNT_INFINITY means "all routes". 285 * We respond to routers only if we are acting 286 * as a supplier, or to anyone other than a router 287 * (i.e. a query). 288 */ 289 if (n->n_family == RIP_AF_UNSPEC 290 && n->n_metric == HOPCNT_INFINITY) { 291 /* Answer a query from a utility program 292 * with all we know. 293 */ 294 if (from->sin_port != htons(RIP_PORT)) { 295 supply(from, aifp, OUT_QUERY, 0, 296 rip->rip_vers, ap != 0); 297 return; 298 } 299 300 /* A router trying to prime its tables. 301 * Filter the answer in the about same way 302 * broadcasts are filtered. 303 * 304 * Only answer a router if we are a supplier 305 * to keep an unwary host that is just starting 306 * from picking us as a router. 307 */ 308 if (aifp == 0) { 309 trace_pkt("ignore distant router"); 310 return; 311 } 312 if (!supplier 313 || IS_RIP_OFF(aifp->int_state)) { 314 trace_pkt("ignore; not supplying"); 315 return; 316 } 317 318 /* Do not answer a RIPv1 router if 319 * we are sending RIPv2. But do offer 320 * poor man's router discovery. 321 */ 322 if ((aifp->int_state & IS_NO_RIPV1_OUT) 323 && rip->rip_vers == RIPv1) { 324 if (!(aifp->int_state & IS_PM_RDISC)) { 325 trace_pkt("ignore; sending RIPv2"); 326 return; 327 } 328 329 v12buf.n->n_family = RIP_AF_INET; 330 v12buf.n->n_dst = RIP_DEFAULT; 331 i = aifp->int_d_metric; 332 if (0 != (rt = rtget(RIP_DEFAULT, 0))) 333 i = MIN(i, (rt->rt_metric 334 +aifp->int_metric+1)); 335 v12buf.n->n_metric = htonl(i); 336 v12buf.n++; 337 break; 338 } 339 340 /* Respond with RIPv1 instead of RIPv2 if 341 * that is what we are broadcasting on the 342 * interface to keep the remote router from 343 * getting the wrong initial idea of the 344 * routes we send. 345 */ 346 supply(from, aifp, OUT_UNICAST, 0, 347 (aifp->int_state & IS_NO_RIPV1_OUT) 348 ? RIPv2 : RIPv1, 349 ap != 0); 350 return; 351 } 352 353 /* Ignore authentication */ 354 if (n->n_family == RIP_AF_AUTH) 355 continue; 356 357 if (n->n_family != RIP_AF_INET) { 358 msglim(&bad_router, FROM_NADDR, 359 "request from %s for unsupported" 360 " (af %d) %s", 361 naddr_ntoa(FROM_NADDR), 362 ntohs(n->n_family), 363 naddr_ntoa(n->n_dst)); 364 return; 365 } 366 367 /* We are being asked about a specific destination. 368 */ 369 dst = n->n_dst; 370 if (!check_dst(dst)) { 371 msglim(&bad_router, FROM_NADDR, 372 "bad queried destination %s from %s", 373 naddr_ntoa(dst), 374 naddr_ntoa(FROM_NADDR)); 375 return; 376 } 377 378 /* decide what mask was intended */ 379 if (rip->rip_vers == RIPv1 380 || 0 == (mask = ntohl(n->n_mask)) 381 || 0 != (ntohl(dst) & ~mask)) 382 mask = ripv1_mask_host(dst, aifp); 383 384 /* try to find the answer */ 385 rt = rtget(dst, mask); 386 if (!rt && dst != RIP_DEFAULT) 387 rt = rtfind(n->n_dst); 388 389 if (v12buf.buf->rip_vers != RIPv1) 390 v12buf.n->n_mask = mask; 391 if (rt == 0) { 392 /* we do not have the answer */ 393 v12buf.n->n_metric = HOPCNT_INFINITY; 394 } else { 395 /* we have the answer, so compute the 396 * right metric and next hop. 397 */ 398 v12buf.n->n_family = RIP_AF_INET; 399 v12buf.n->n_dst = dst; 400 v12buf.n->n_metric = (rt->rt_metric+1 401 + ((aifp!=0) 402 ? aifp->int_metric 403 : 1)); 404 if (v12buf.n->n_metric > HOPCNT_INFINITY) 405 v12buf.n->n_metric = HOPCNT_INFINITY; 406 if (v12buf.buf->rip_vers != RIPv1) { 407 v12buf.n->n_tag = rt->rt_tag; 408 v12buf.n->n_mask = mask; 409 if (aifp != 0 410 && on_net(rt->rt_gate, 411 aifp->int_net, 412 aifp->int_mask) 413 && rt->rt_gate != aifp->int_addr) 414 v12buf.n->n_nhop = rt->rt_gate; 415 } 416 } 417 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 418 419 /* Stop paying attention if we fill the output buffer. 420 */ 421 if (++v12buf.n >= v12buf.lim) 422 break; 423 } while (++n < lim); 424 425 /* Send the answer about specific routes. 426 */ 427 if (ap != 0 && ap->type == RIP_AUTH_MD5) 428 end_md5_auth(&v12buf, ap); 429 430 if (from->sin_port != htons(RIP_PORT)) { 431 /* query */ 432 output(OUT_QUERY, from, aifp, 433 v12buf.buf, 434 ((char *)v12buf.n - (char*)v12buf.buf)); 435 } else if (supplier) { 436 output(OUT_UNICAST, from, aifp, 437 v12buf.buf, 438 ((char *)v12buf.n - (char*)v12buf.buf)); 439 } else { 440 /* Only answer a router if we are a supplier 441 * to keep an unwary host that is just starting 442 * from picking us an a router. 443 */ 444 ; 445 } 446 return; 447 448 case RIPCMD_TRACEON: 449 case RIPCMD_TRACEOFF: 450 /* Notice that trace messages are turned off for all possible 451 * abuse if _PATH_TRACE is undefined in pathnames.h. 452 * Notice also that because of the way the trace file is 453 * handled in trace.c, no abuse is plausible even if 454 * _PATH_TRACE_ is defined. 455 * 456 * First verify message came from a privileged port. */ 457 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 458 msglog("trace command from untrusted port on %s", 459 naddr_ntoa(FROM_NADDR)); 460 return; 461 } 462 if (aifp == 0) { 463 msglog("trace command from unknown router %s", 464 naddr_ntoa(FROM_NADDR)); 465 return; 466 } 467 if (rip->rip_cmd == RIPCMD_TRACEON) { 468 rip->rip_tracefile[cc-4] = '\0'; 469 set_tracefile((char*)rip->rip_tracefile, 470 "trace command: %s\n", 0); 471 } else { 472 trace_off("tracing turned off by %s", 473 naddr_ntoa(FROM_NADDR)); 474 } 475 return; 476 477 case RIPCMD_RESPONSE: 478 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 479 msglim(&bad_len, FROM_NADDR, 480 "response of bad length (%d) from %s", 481 cc, naddr_ntoa(FROM_NADDR)); 482 } 483 484 /* verify message came from a router */ 485 if (from->sin_port != ntohs(RIP_PORT)) { 486 msglim(&bad_router, FROM_NADDR, 487 " discard RIP response from unknown port" 488 " %d on host %s", ntohs(from->sin_port), 489 naddr_ntoa(FROM_NADDR)); 490 return; 491 } 492 493 if (rip_sock < 0) { 494 trace_pkt(" discard response while RIP off"); 495 return; 496 } 497 498 /* Are we talking to ourself or a remote gateway? 499 */ 500 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 501 if (ifp1) { 502 if (ifp1->int_state & IS_REMOTE) { 503 /* remote gateway */ 504 aifp = ifp1; 505 if (check_remote(aifp)) { 506 aifp->int_act_time = now.tv_sec; 507 if_ok(aifp, "remote "); 508 } 509 } else { 510 trace_pkt(" discard our own RIP response"); 511 return; 512 } 513 } 514 515 /* Accept routing packets from routers directly connected 516 * via broadcast or point-to-point networks, and from 517 * those listed in /etc/gateways. 518 */ 519 if (aifp == 0) { 520 msglim(&unk_router, FROM_NADDR, 521 " discard response from %s" 522 " via unexpected interface", 523 naddr_ntoa(FROM_NADDR)); 524 return; 525 } 526 if (IS_RIP_IN_OFF(aifp->int_state)) { 527 trace_pkt(" discard RIPv%d response" 528 " via disabled interface %s", 529 rip->rip_vers, aifp->int_name); 530 return; 531 } 532 533 if (n >= lim) { 534 msglim(&bad_len, FROM_NADDR, "empty response from %s", 535 naddr_ntoa(FROM_NADDR)); 536 return; 537 } 538 539 if (((aifp->int_state & IS_NO_RIPV1_IN) 540 && rip->rip_vers == RIPv1) 541 || ((aifp->int_state & IS_NO_RIPV2_IN) 542 && rip->rip_vers != RIPv1)) { 543 trace_pkt(" discard RIPv%d response", 544 rip->rip_vers); 545 return; 546 } 547 548 /* Ignore routes via dead interface. 549 */ 550 if (aifp->int_state & IS_BROKE) { 551 trace_pkt("discard response via broken interface %s", 552 aifp->int_name); 553 return; 554 } 555 556 /* If the interface cares, ignore bad routers. 557 * Trace but do not log this problem, because where it 558 * happens, it happens frequently. 559 */ 560 if (aifp->int_state & IS_DISTRUST) { 561 tg = tgates; 562 while (tg->tgate_addr != FROM_NADDR) { 563 tg = tg->tgate_next; 564 if (tg == 0) { 565 trace_pkt(" discard RIP response" 566 " from untrusted router %s", 567 naddr_ntoa(FROM_NADDR)); 568 return; 569 } 570 } 571 } 572 573 /* Authenticate the packet if we have a secret. 574 * If we do not have any secrets, ignore the error in 575 * RFC 1723 and accept it regardless. 576 */ 577 if (aifp->int_auth[0].type != RIP_AUTH_NONE 578 && rip->rip_vers != RIPv1 579 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 580 return; 581 582 do { 583 if (n->n_family == RIP_AF_AUTH) 584 continue; 585 586 n->n_metric = ntohl(n->n_metric); 587 dst = n->n_dst; 588 if (n->n_family != RIP_AF_INET 589 && (n->n_family != RIP_AF_UNSPEC 590 || dst != RIP_DEFAULT)) { 591 msglim(&bad_router, FROM_NADDR, 592 "route from %s to unsupported" 593 " address family=%d destination=%s", 594 naddr_ntoa(FROM_NADDR), 595 n->n_family, 596 naddr_ntoa(dst)); 597 continue; 598 } 599 if (!check_dst(dst)) { 600 msglim(&bad_router, FROM_NADDR, 601 "bad destination %s from %s", 602 naddr_ntoa(dst), 603 naddr_ntoa(FROM_NADDR)); 604 return; 605 } 606 if (n->n_metric == 0 607 || n->n_metric > HOPCNT_INFINITY) { 608 msglim(&bad_router, FROM_NADDR, 609 "bad metric %d from %s" 610 " for destination %s", 611 n->n_metric, 612 naddr_ntoa(FROM_NADDR), 613 naddr_ntoa(dst)); 614 return; 615 } 616 617 /* Notice the next-hop. 618 */ 619 gate = FROM_NADDR; 620 if (n->n_nhop != 0) { 621 if (rip->rip_vers == RIPv1) { 622 n->n_nhop = 0; 623 } else { 624 /* Use it only if it is valid. */ 625 if (on_net(n->n_nhop, 626 aifp->int_net, aifp->int_mask) 627 && check_dst(n->n_nhop)) { 628 gate = n->n_nhop; 629 } else { 630 msglim(&bad_nhop, FROM_NADDR, 631 "router %s to %s" 632 " has bad next hop %s", 633 naddr_ntoa(FROM_NADDR), 634 naddr_ntoa(dst), 635 naddr_ntoa(n->n_nhop)); 636 n->n_nhop = 0; 637 } 638 } 639 } 640 641 if (rip->rip_vers == RIPv1 642 || 0 == (mask = ntohl(n->n_mask))) { 643 mask = ripv1_mask_host(dst,aifp); 644 } else if ((ntohl(dst) & ~mask) != 0) { 645 msglim(&bad_mask, FROM_NADDR, 646 "router %s sent bad netmask" 647 " %#lx with %s", 648 naddr_ntoa(FROM_NADDR), 649 (u_long)mask, 650 naddr_ntoa(dst)); 651 continue; 652 } 653 if (rip->rip_vers == RIPv1) 654 n->n_tag = 0; 655 656 /* Adjust metric according to incoming interface.. 657 */ 658 n->n_metric += aifp->int_metric; 659 if (n->n_metric > HOPCNT_INFINITY) 660 n->n_metric = HOPCNT_INFINITY; 661 662 /* Should we trust this route from this router? */ 663 if (tg && (tn = tg->tgate_nets)->mask != 0) { 664 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 665 if (on_net(dst, tn->net, tn->mask) 666 && tn->mask <= mask) 667 break; 668 } 669 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 670 trace_pkt(" ignored unauthorized %s", 671 addrname(dst,mask,0)); 672 continue; 673 } 674 } 675 676 /* Recognize and ignore a default route we faked 677 * which is being sent back to us by a machine with 678 * broken split-horizon. 679 * Be a little more paranoid than that, and reject 680 * default routes with the same metric we advertised. 681 */ 682 if (aifp->int_d_metric != 0 683 && dst == RIP_DEFAULT 684 && (int)n->n_metric >= aifp->int_d_metric) 685 continue; 686 687 /* We can receive aggregated RIPv2 routes that must 688 * be broken down before they are transmitted by 689 * RIPv1 via an interface on a subnet. 690 * We might also receive the same routes aggregated 691 * via other RIPv2 interfaces. 692 * This could cause duplicate routes to be sent on 693 * the RIPv1 interfaces. "Longest matching variable 694 * length netmasks" lets RIPv2 listeners understand, 695 * but breaking down the aggregated routes for RIPv1 696 * listeners can produce duplicate routes. 697 * 698 * Breaking down aggregated routes here bloats 699 * the daemon table, but does not hurt the kernel 700 * table, since routes are always aggregated for 701 * the kernel. 702 * 703 * Notice that this does not break down network 704 * routes corresponding to subnets. This is part 705 * of the defense against RS_NET_SYN. 706 */ 707 if (have_ripv1_out 708 && (((rt = rtget(dst,mask)) == 0 709 || !(rt->rt_state & RS_NET_SYN))) 710 && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 711 ddst_h = v1_mask & -v1_mask; 712 i = (v1_mask & ~mask)/ddst_h; 713 if (i >= 511) { 714 /* Punt if we would have to generate 715 * an unreasonable number of routes. 716 */ 717 if (TRACECONTENTS) 718 trace_misc("accept %s-->%s as 1" 719 " instead of %d routes", 720 addrname(dst,mask,0), 721 naddr_ntoa(FROM_NADDR), 722 i+1); 723 i = 0; 724 } else { 725 mask = v1_mask; 726 } 727 } else { 728 i = 0; 729 } 730 731 new.rts_gate = gate; 732 new.rts_router = FROM_NADDR; 733 new.rts_metric = n->n_metric; 734 new.rts_tag = n->n_tag; 735 new.rts_time = now.tv_sec; 736 new.rts_ifp = aifp; 737 new.rts_de_ag = i; 738 j = 0; 739 for (;;) { 740 input_route(dst, mask, &new, n); 741 if (++j > i) 742 break; 743 dst = htonl(ntohl(dst) + ddst_h); 744 } 745 } while (++n < lim); 746 break; 747 } 748 #undef FROM_NADDR 749 } 750 751 752 /* Process a single input route. 753 */ 754 static void 755 input_route(naddr dst, /* network order */ 756 naddr mask, 757 struct rt_spare *new, 758 struct netinfo *n) 759 { 760 int i; 761 struct rt_entry *rt; 762 struct rt_spare *rts, *rts0; 763 struct interface *ifp1; 764 765 766 /* See if the other guy is telling us to send our packets to him. 767 * Sometimes network routes arrive over a point-to-point link for 768 * the network containing the address(es) of the link. 769 * 770 * If our interface is broken, switch to using the other guy. 771 */ 772 ifp1 = ifwithaddr(dst, 1, 1); 773 if (ifp1 != 0 774 && (!(ifp1->int_state & IS_BROKE) 775 || (ifp1->int_state & IS_PASSIVE))) 776 return; 777 778 /* Look for the route in our table. 779 */ 780 rt = rtget(dst, mask); 781 782 /* Consider adding the route if we do not already have it. 783 */ 784 if (rt == 0) { 785 /* Ignore unknown routes being poisoned. 786 */ 787 if (new->rts_metric == HOPCNT_INFINITY) 788 return; 789 790 /* Ignore the route if it points to us */ 791 if (n->n_nhop != 0 792 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 793 return; 794 795 /* If something has not gone crazy and tried to fill 796 * our memory, accept the new route. 797 */ 798 if (total_routes < MAX_ROUTES) 799 rtadd(dst, mask, 0, new); 800 return; 801 } 802 803 /* We already know about the route. Consider this update. 804 * 805 * If (rt->rt_state & RS_NET_SYN), then this route 806 * is the same as a network route we have inferred 807 * for subnets we know, in order to tell RIPv1 routers 808 * about the subnets. 809 * 810 * It is impossible to tell if the route is coming 811 * from a distant RIPv2 router with the standard 812 * netmask because that router knows about the entire 813 * network, or if it is a round-about echo of a 814 * synthetic, RIPv1 network route of our own. 815 * The worst is that both kinds of routes might be 816 * received, and the bad one might have the smaller 817 * metric. Partly solve this problem by never 818 * aggregating into such a route. Also keep it 819 * around as long as the interface exists. 820 */ 821 822 rts0 = rt->rt_spares; 823 for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 824 if (rts->rts_router == new->rts_router) 825 break; 826 /* Note the worst slot to reuse, 827 * other than the current slot. 828 */ 829 if (rts0 == rt->rt_spares 830 || BETTER_LINK(rt, rts0, rts)) 831 rts0 = rts; 832 } 833 if (i != 0) { 834 /* Found a route from the router already in the table. 835 */ 836 837 /* If the new route is a route broken down from an 838 * aggregated route, and if the previous route is either 839 * not a broken down route or was broken down from a finer 840 * netmask, and if the previous route is current, 841 * then forget this one. 842 */ 843 if (new->rts_de_ag > rts->rts_de_ag 844 && now_stale <= rts->rts_time) 845 return; 846 847 /* Keep poisoned routes around only long enough to pass 848 * the poison on. Use a new timestamp for good routes. 849 */ 850 if (rts->rts_metric == HOPCNT_INFINITY 851 && new->rts_metric == HOPCNT_INFINITY) 852 new->rts_time = rts->rts_time; 853 854 /* If this is an update for the router we currently prefer, 855 * then note it. 856 */ 857 if (i == NUM_SPARES) { 858 rtchange(rt, rt->rt_state, new, 0); 859 /* If the route got worse, check for something better. 860 */ 861 if (new->rts_metric > rts->rts_metric) 862 rtswitch(rt, 0); 863 return; 864 } 865 866 /* This is an update for a spare route. 867 * Finished if the route is unchanged. 868 */ 869 if (rts->rts_gate == new->rts_gate 870 && rts->rts_metric == new->rts_metric 871 && rts->rts_tag == new->rts_tag) { 872 trace_upslot(rt, rts, new); 873 *rts = *new; 874 return; 875 } 876 /* Forget it if it has gone bad. 877 */ 878 if (new->rts_metric == HOPCNT_INFINITY) { 879 rts_delete(rt, rts); 880 return; 881 } 882 883 } else { 884 /* The update is for a route we know about, 885 * but not from a familiar router. 886 * 887 * Ignore the route if it points to us. 888 */ 889 if (n->n_nhop != 0 890 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 891 return; 892 893 /* the loop above set rts0=worst spare */ 894 rts = rts0; 895 896 /* Save the route as a spare only if it has 897 * a better metric than our worst spare. 898 * This also ignores poisoned routes (those 899 * received with metric HOPCNT_INFINITY). 900 */ 901 if (new->rts_metric >= rts->rts_metric) 902 return; 903 } 904 905 trace_upslot(rt, rts, new); 906 *rts = *new; 907 908 /* try to switch to a better route */ 909 rtswitch(rt, rts); 910 } 911 912 913 static int /* 0 if bad */ 914 ck_passwd(struct interface *aifp, 915 struct rip *rip, 916 void *lim, 917 naddr from, 918 struct msg_limit *use_authp) 919 { 920 # define NA (rip->rip_auths) 921 struct netauth *na2; 922 struct auth *ap; 923 MD5_CTX md5_ctx; 924 u_char hash[RIP_AUTH_PW_LEN]; 925 int i, len; 926 927 928 if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 929 msglim(use_authp, from, "missing password from %s", 930 naddr_ntoa(from)); 931 return 0; 932 } 933 934 /* accept any current (+/- 24 hours) password 935 */ 936 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 937 if (ap->type != NA->a_type 938 || (u_long)ap->start > (u_long)clk.tv_sec+DAY 939 || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 940 continue; 941 942 if (NA->a_type == RIP_AUTH_PW) { 943 if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 944 return 1; 945 946 } else { 947 /* accept MD5 secret with the right key ID 948 */ 949 if (NA->au.a_md5.md5_keyid != ap->keyid) 950 continue; 951 952 len = ntohs(NA->au.a_md5.md5_pkt_len); 953 if ((len-sizeof(*rip)) % sizeof(*NA) != 0 954 || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 955 msglim(use_authp, from, 956 "wrong MD5 RIPv2 packet length of %d" 957 " instead of %d from %s", 958 len, (int)((char *)lim-(char *)rip 959 -sizeof(*NA)), 960 naddr_ntoa(from)); 961 return 0; 962 } 963 na2 = (struct netauth *)((char *)rip+len); 964 965 /* Given a good hash value, these are not security 966 * problems so be generous and accept the routes, 967 * after complaining. 968 */ 969 if (TRACEPACKETS) { 970 if (NA->au.a_md5.md5_auth_len 971 != RIP_AUTH_MD5_LEN) 972 msglim(use_authp, from, 973 "unknown MD5 RIPv2 auth len %#x" 974 " instead of %#x from %s", 975 NA->au.a_md5.md5_auth_len, 976 RIP_AUTH_MD5_LEN, 977 naddr_ntoa(from)); 978 if (na2->a_family != RIP_AF_AUTH) 979 msglim(use_authp, from, 980 "unknown MD5 RIPv2 family %#x" 981 " instead of %#x from %s", 982 na2->a_family, RIP_AF_AUTH, 983 naddr_ntoa(from)); 984 if (na2->a_type != ntohs(1)) 985 msglim(use_authp, from, 986 "MD5 RIPv2 hash has %#x" 987 " instead of %#x from %s", 988 na2->a_type, ntohs(1), 989 naddr_ntoa(from)); 990 } 991 992 MD5Init(&md5_ctx); 993 MD5Update(&md5_ctx, (u_char *)rip, len); 994 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); 995 MD5Final(hash, &md5_ctx); 996 if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 997 return 1; 998 } 999 } 1000 1001 msglim(use_authp, from, "bad password from %s", 1002 naddr_ntoa(from)); 1003 return 0; 1004 #undef NA 1005 } 1006