1 /* $NetBSD: input.c,v 1.31 2009/10/26 02:53:15 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgment: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include "defs.h" 37 38 #ifdef __NetBSD__ 39 __RCSID("$NetBSD: input.c,v 1.31 2009/10/26 02:53:15 christos Exp $"); 40 #elif defined(__FreeBSD__) 41 __RCSID("$FreeBSD$"); 42 #else 43 __RCSID("Revision: 2.26 "); 44 #ident "Revision: 2.26 " 45 #endif 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 socklen_t fromlen; 63 int cc; 64 #ifdef USE_PASSIFNAME 65 static struct msg_limit bad_name; 66 struct { 67 char ifname[IFNAMSIZ]; 68 union pkt_buf pbuf; 69 } inbuf; 70 #else 71 struct { 72 union pkt_buf pbuf; 73 } inbuf; 74 #endif 75 76 77 for (;;) { 78 fromlen = sizeof(from); 79 cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 80 (struct sockaddr*)&from, &fromlen); 81 if (cc <= 0) { 82 if (cc < 0 && errno != EWOULDBLOCK) 83 LOGERR("recvfrom(rip)"); 84 break; 85 } 86 if (fromlen != sizeof(struct sockaddr_in)) 87 logbad(1,"impossible recvfrom(rip) fromlen=%d", 88 fromlen); 89 90 /* aifp is the "authenticated" interface via which the packet 91 * arrived. In fact, it is only the interface on which 92 * the packet should have arrived based on is source 93 * address. 94 * sifp is interface associated with the socket through which 95 * the packet was received. 96 */ 97 #ifdef USE_PASSIFNAME 98 if ((cc -= sizeof(inbuf.ifname)) < 0) 99 logbad(0,"missing USE_PASSIFNAME; only %d bytes", 100 cc+sizeof(inbuf.ifname)); 101 102 /* check the remote interfaces first */ 103 for (aifp = remote_if; aifp; aifp = aifp->int_rlink) { 104 if (aifp->int_addr == from.sin_addr.s_addr) 105 break; 106 } 107 if (aifp == 0) { 108 aifp = ifwithname(inbuf.ifname, 0); 109 if (aifp == 0) { 110 msglim(&bad_name, from.sin_addr.s_addr, 111 "impossible interface name %.*s", 112 IFNAMSIZ, inbuf.ifname); 113 } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 114 && aifp->int_dstaddr!=from.sin_addr.s_addr) 115 || (!(aifp->int_if_flags & IFF_POINTOPOINT) 116 && !on_net(from.sin_addr.s_addr, 117 aifp->int_net, 118 aifp->int_mask))) { 119 /* If it came via the wrong interface, do not 120 * trust it. 121 */ 122 aifp = 0; 123 } 124 } 125 #else 126 aifp = iflookup(from.sin_addr.s_addr); 127 #endif 128 if (sifp == 0) 129 sifp = aifp; 130 131 input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 132 } 133 } 134 135 136 /* Process a RIP packet 137 */ 138 static void 139 input(struct sockaddr_in *from, /* received from this IP address */ 140 struct interface *sifp, /* interface of incoming socket */ 141 struct interface *aifp, /* "authenticated" interface */ 142 struct rip *rip, 143 int cc) 144 { 145 # define FROM_NADDR from->sin_addr.s_addr 146 static struct msg_limit use_auth, bad_len, bad_mask; 147 static struct msg_limit unk_router, bad_router, bad_nhop; 148 149 struct rt_entry *rt; 150 struct rt_spare new; 151 struct netinfo *n, *lim; 152 struct interface *ifp1; 153 naddr gate, mask, v1_mask, dst, ddst_h = 0; 154 struct auth *ap; 155 struct tgate *tg = 0; 156 struct tgate_net *tn; 157 int i, j; 158 159 /* Notice when we hear from a remote gateway 160 */ 161 if (aifp != 0 162 && (aifp->int_state & IS_REMOTE)) 163 aifp->int_act_time = now.tv_sec; 164 165 trace_rip("Recv", "from", from, sifp, rip, cc); 166 167 if (rip->rip_vers == 0) { 168 msglim(&bad_router, FROM_NADDR, 169 "RIP version 0, cmd %d, packet received from %s", 170 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 171 return; 172 } else if (rip->rip_vers > RIPv2) { 173 rip->rip_vers = RIPv2; 174 } 175 if (cc > (int)OVER_MAXPACKETSIZE) { 176 msglim(&bad_router, FROM_NADDR, 177 "packet at least %d bytes too long received from %s", 178 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 179 return; 180 } 181 182 n = rip->rip_nets; 183 lim = (struct netinfo *)((char*)rip + cc); 184 185 /* Notice authentication. 186 * As required by section 4.2 in RFC 1723, discard authenticated 187 * RIPv2 messages, but only if configured for that silliness. 188 * 189 * RIPv2 authentication is lame. Why authenticate queries? 190 * Why should a RIPv2 implementation with authentication disabled 191 * not be able to listen to RIPv2 packets with authentication, while 192 * RIPv1 systems will listen? Crazy! 193 */ 194 if (!auth_ok 195 && rip->rip_vers == RIPv2 196 && n < lim && n->n_family == RIP_AF_AUTH) { 197 msglim(&use_auth, FROM_NADDR, 198 "RIPv2 message with authentication from %s discarded", 199 naddr_ntoa(FROM_NADDR)); 200 return; 201 } 202 203 switch (rip->rip_cmd) { 204 case RIPCMD_REQUEST: 205 /* For mere requests, be a little sloppy about the source 206 */ 207 if (aifp == 0) 208 aifp = sifp; 209 210 /* Are we talking to ourself or a remote gateway? 211 */ 212 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 213 if (ifp1) { 214 if (ifp1->int_state & IS_REMOTE) { 215 /* remote gateway */ 216 aifp = ifp1; 217 if (check_remote(aifp)) { 218 aifp->int_act_time = now.tv_sec; 219 (void)if_ok(aifp, "remote "); 220 } 221 } else if (from->sin_port == htons(RIP_PORT)) { 222 trace_pkt(" discard our own RIP request"); 223 return; 224 } 225 } 226 227 /* did the request come from a router? 228 */ 229 if (from->sin_port == htons(RIP_PORT)) { 230 /* yes, ignore the request if RIP is off so that 231 * the router does not depend on us. 232 */ 233 if (rip_sock < 0 234 || (aifp != 0 235 && IS_RIP_OUT_OFF(aifp->int_state))) { 236 trace_pkt(" discard request while RIP off"); 237 return; 238 } 239 } 240 241 /* According to RFC 1723, we should ignore unauthenticated 242 * queries. That is too silly to bother with. Sheesh! 243 * Are forwarding tables supposed to be secret, when 244 * a bad guy can infer them with test traffic? When RIP 245 * is still the most common router-discovery protocol 246 * and so hosts need to send queries that will be answered? 247 * What about `rtquery`? 248 * Maybe on firewalls you'd care, but not enough to 249 * give up the diagnostic facilities of remote probing. 250 */ 251 252 if (n >= lim) { 253 msglim(&bad_len, FROM_NADDR, "empty request from %s", 254 naddr_ntoa(FROM_NADDR)); 255 return; 256 } 257 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 258 msglim(&bad_len, FROM_NADDR, 259 "request of bad length (%d) from %s", 260 cc, naddr_ntoa(FROM_NADDR)); 261 } 262 263 if (rip->rip_vers == RIPv2 264 && (aifp == 0 || (aifp->int_state & IS_NO_RIPV1_OUT))) { 265 v12buf.buf->rip_vers = RIPv2; 266 /* If we have a secret but it is a cleartext secret, 267 * do not disclose our secret unless the other guy 268 * already knows it. 269 */ 270 ap = find_auth(aifp); 271 if (ap != 0 && ap->type == RIP_AUTH_PW 272 && n->n_family == RIP_AF_AUTH 273 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 274 ap = 0; 275 } else { 276 v12buf.buf->rip_vers = RIPv1; 277 ap = 0; 278 } 279 clr_ws_buf(&v12buf, ap); 280 281 do { 282 n->n_metric = ntohl(n->n_metric); 283 284 /* A single entry with family RIP_AF_UNSPEC and 285 * metric HOPCNT_INFINITY means "all routes". 286 * We respond to routers only if we are acting 287 * as a supplier, or to anyone other than a router 288 * (i.e. a query). 289 */ 290 if (n->n_family == RIP_AF_UNSPEC 291 && n->n_metric == HOPCNT_INFINITY) { 292 /* Answer a query from a utility program 293 * with all we know. 294 */ 295 if (from->sin_port != htons(RIP_PORT)) { 296 supply(from, aifp, OUT_QUERY, 0, 297 rip->rip_vers, ap != 0); 298 return; 299 } 300 301 /* A router trying to prime its tables. 302 * Filter the answer in the about same way 303 * broadcasts are filtered. 304 * 305 * Only answer a router if we are a supplier 306 * to keep an unwary host that is just starting 307 * from picking us as a router. 308 */ 309 if (aifp == 0) { 310 trace_pkt("ignore distant router"); 311 return; 312 } 313 if (!supplier 314 || IS_RIP_OFF(aifp->int_state)) { 315 trace_pkt("ignore; not supplying"); 316 return; 317 } 318 319 /* Do not answer a RIPv1 router if 320 * we are sending RIPv2. But do offer 321 * poor man's router discovery. 322 */ 323 if ((aifp->int_state & IS_NO_RIPV1_OUT) 324 && rip->rip_vers == RIPv1) { 325 if (!(aifp->int_state & IS_PM_RDISC)) { 326 trace_pkt("ignore; sending RIPv2"); 327 return; 328 } 329 330 v12buf.n->n_family = RIP_AF_INET; 331 v12buf.n->n_dst = RIP_DEFAULT; 332 i = aifp->int_d_metric; 333 if (0 != (rt = rtget(RIP_DEFAULT, 0))) { 334 j = (rt->rt_metric 335 +aifp->int_metric 336 +aifp->int_adj_outmetric 337 +1); 338 if (i > j) 339 i = j; 340 } 341 v12buf.n->n_metric = htonl(i); 342 v12buf.n++; 343 break; 344 } 345 346 /* Respond with RIPv1 instead of RIPv2 if 347 * that is what we are broadcasting on the 348 * interface to keep the remote router from 349 * getting the wrong initial idea of the 350 * routes we send. 351 */ 352 supply(from, aifp, OUT_UNICAST, 0, 353 (aifp->int_state & IS_NO_RIPV1_OUT) 354 ? RIPv2 : RIPv1, 355 ap != 0); 356 return; 357 } 358 359 /* Ignore authentication */ 360 if (n->n_family == RIP_AF_AUTH) 361 continue; 362 363 if (n->n_family != RIP_AF_INET) { 364 msglim(&bad_router, FROM_NADDR, 365 "request from %s for unsupported" 366 " (af %d) %s", 367 naddr_ntoa(FROM_NADDR), 368 ntohs(n->n_family), 369 naddr_ntoa(n->n_dst)); 370 return; 371 } 372 373 /* We are being asked about a specific destination. 374 */ 375 dst = n->n_dst; 376 if (!check_dst(dst)) { 377 msglim(&bad_router, FROM_NADDR, 378 "bad queried destination %s from %s", 379 naddr_ntoa(dst), 380 naddr_ntoa(FROM_NADDR)); 381 return; 382 } 383 384 /* decide what mask was intended */ 385 if (rip->rip_vers == RIPv1 386 || 0 == (mask = ntohl(n->n_mask)) 387 || 0 != (ntohl(dst) & ~mask)) 388 mask = ripv1_mask_host(dst, aifp); 389 390 /* try to find the answer */ 391 rt = rtget(dst, mask); 392 if (!rt && dst != RIP_DEFAULT) 393 rt = rtfind(n->n_dst); 394 395 if (v12buf.buf->rip_vers != RIPv1) 396 v12buf.n->n_mask = mask; 397 if (rt == 0) { 398 /* we do not have the answer */ 399 v12buf.n->n_metric = HOPCNT_INFINITY; 400 } else { 401 /* we have the answer, so compute the 402 * right metric and next hop. 403 */ 404 v12buf.n->n_family = RIP_AF_INET; 405 v12buf.n->n_dst = dst; 406 j = rt->rt_metric+1; 407 if (!aifp) 408 ++j; 409 else 410 j += (aifp->int_metric 411 + aifp->int_adj_outmetric); 412 if (j < HOPCNT_INFINITY) 413 v12buf.n->n_metric = j; 414 else 415 v12buf.n->n_metric = HOPCNT_INFINITY; 416 if (v12buf.buf->rip_vers != RIPv1) { 417 v12buf.n->n_tag = rt->rt_tag; 418 v12buf.n->n_mask = mask; 419 if (aifp != 0 420 && on_net(rt->rt_gate, 421 aifp->int_net, 422 aifp->int_mask) 423 && rt->rt_gate != aifp->int_addr) 424 v12buf.n->n_nhop = rt->rt_gate; 425 } 426 } 427 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 428 429 /* Stop paying attention if we fill the output buffer. 430 */ 431 if (++v12buf.n >= v12buf.lim) 432 break; 433 } while (++n < lim); 434 435 /* Send the answer about specific routes. 436 */ 437 if (ap != 0 && ap->type == RIP_AUTH_MD5) 438 end_md5_auth(&v12buf, ap); 439 440 if (from->sin_port != htons(RIP_PORT)) { 441 /* query */ 442 (void)output(OUT_QUERY, from, aifp, 443 v12buf.buf, 444 ((char *)v12buf.n - (char*)v12buf.buf)); 445 } else if (supplier) { 446 (void)output(OUT_UNICAST, from, aifp, 447 v12buf.buf, 448 ((char *)v12buf.n - (char*)v12buf.buf)); 449 } else { 450 /* Only answer a router if we are a supplier 451 * to keep an unwary host that is just starting 452 * from picking us an a router. 453 */ 454 ; 455 } 456 return; 457 458 case RIPCMD_TRACEON: 459 case RIPCMD_TRACEOFF: 460 /* Notice that trace messages are turned off for all possible 461 * abuse if _PATH_TRACE is undefined in pathnames.h. 462 * Notice also that because of the way the trace file is 463 * handled in trace.c, no abuse is plausible even if 464 * _PATH_TRACE_ is defined. 465 * 466 * First verify message came from a privileged port. */ 467 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 468 msglog("trace command from untrusted port on %s", 469 naddr_ntoa(FROM_NADDR)); 470 return; 471 } 472 if (aifp == 0) { 473 msglog("trace command from unknown router %s", 474 naddr_ntoa(FROM_NADDR)); 475 return; 476 } 477 if (rip->rip_cmd == RIPCMD_TRACEON) { 478 rip->rip_tracefile[cc-4] = '\0'; 479 #ifndef __NetBSD__ 480 set_tracefile((char*)rip->rip_tracefile, 481 "trace command: %s\n", 0); 482 #else 483 msglog("RIP_TRACEON for `%s' from %s ignored", 484 (char *) rip->rip_tracefile, 485 naddr_ntoa(FROM_NADDR)); 486 #endif 487 } else { 488 #ifndef __NetBSD__ 489 trace_off("tracing turned off by %s", 490 naddr_ntoa(FROM_NADDR)); 491 #else 492 msglog("RIP_TRACEOFF from %s ignored", 493 naddr_ntoa(FROM_NADDR)); 494 #endif 495 } 496 return; 497 498 case RIPCMD_RESPONSE: 499 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 500 msglim(&bad_len, FROM_NADDR, 501 "response of bad length (%d) from %s", 502 cc, naddr_ntoa(FROM_NADDR)); 503 } 504 505 /* verify message came from a router */ 506 if (from->sin_port != ntohs(RIP_PORT)) { 507 msglim(&bad_router, FROM_NADDR, 508 " discard RIP response from unknown port" 509 " %d on %s", 510 ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); 511 return; 512 } 513 514 if (rip_sock < 0) { 515 trace_pkt(" discard response while RIP off"); 516 return; 517 } 518 519 /* Are we talking to ourself or a remote gateway? 520 */ 521 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 522 if (ifp1) { 523 if (ifp1->int_state & IS_REMOTE) { 524 /* remote gateway */ 525 aifp = ifp1; 526 if (check_remote(aifp)) { 527 aifp->int_act_time = now.tv_sec; 528 (void)if_ok(aifp, "remote "); 529 } 530 } else { 531 trace_pkt(" discard our own RIP response"); 532 return; 533 } 534 } 535 536 /* Accept routing packets from routers directly connected 537 * via broadcast or point-to-point networks, and from 538 * those listed in /etc/gateways. 539 */ 540 if (aifp == 0) { 541 msglim(&unk_router, FROM_NADDR, 542 " discard response from %s" 543 " via unexpected interface", 544 naddr_ntoa(FROM_NADDR)); 545 return; 546 } 547 if (IS_RIP_IN_OFF(aifp->int_state)) { 548 trace_pkt(" discard RIPv%d response" 549 " via disabled interface %s", 550 rip->rip_vers, aifp->int_name); 551 return; 552 } 553 554 if (n >= lim) { 555 msglim(&bad_len, FROM_NADDR, "empty response from %s", 556 naddr_ntoa(FROM_NADDR)); 557 return; 558 } 559 560 if (((aifp->int_state & IS_NO_RIPV1_IN) 561 && rip->rip_vers == RIPv1) 562 || ((aifp->int_state & IS_NO_RIPV2_IN) 563 && rip->rip_vers != RIPv1)) { 564 trace_pkt(" discard RIPv%d response", 565 rip->rip_vers); 566 return; 567 } 568 569 /* Ignore routes via dead interface. 570 */ 571 if (aifp->int_state & IS_BROKE) { 572 trace_pkt("discard response via broken interface %s", 573 aifp->int_name); 574 return; 575 } 576 577 /* If the interface cares, ignore bad routers. 578 * Trace but do not log this problem, because where it 579 * happens, it happens frequently. 580 */ 581 if (aifp->int_state & IS_DISTRUST) { 582 tg = tgates; 583 while (tg->tgate_addr != FROM_NADDR) { 584 tg = tg->tgate_next; 585 if (tg == 0) { 586 trace_pkt(" discard RIP response" 587 " from untrusted router %s", 588 naddr_ntoa(FROM_NADDR)); 589 return; 590 } 591 } 592 } 593 594 /* Authenticate the packet if we have a secret. 595 * If we do not have any secrets, ignore the error in 596 * RFC 1723 and accept it regardless. 597 */ 598 if (aifp->int_auth[0].type != RIP_AUTH_NONE 599 && rip->rip_vers != RIPv1 600 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 601 return; 602 603 do { 604 if (n->n_family == RIP_AF_AUTH) 605 continue; 606 607 n->n_metric = ntohl(n->n_metric); 608 dst = n->n_dst; 609 if (n->n_family != RIP_AF_INET 610 && (n->n_family != RIP_AF_UNSPEC 611 || dst != RIP_DEFAULT)) { 612 msglim(&bad_router, FROM_NADDR, 613 "route from %s to unsupported" 614 " address family=%d destination=%s", 615 naddr_ntoa(FROM_NADDR), 616 n->n_family, 617 naddr_ntoa(dst)); 618 continue; 619 } 620 if (!check_dst(dst)) { 621 msglim(&bad_router, FROM_NADDR, 622 "bad destination %s from %s", 623 naddr_ntoa(dst), 624 naddr_ntoa(FROM_NADDR)); 625 return; 626 } 627 if (n->n_metric == 0 628 || n->n_metric > HOPCNT_INFINITY) { 629 msglim(&bad_router, FROM_NADDR, 630 "bad metric %d from %s" 631 " for destination %s", 632 n->n_metric, 633 naddr_ntoa(FROM_NADDR), 634 naddr_ntoa(dst)); 635 return; 636 } 637 638 /* Notice the next-hop. 639 */ 640 gate = FROM_NADDR; 641 if (n->n_nhop != 0) { 642 if (rip->rip_vers == RIPv1) { 643 n->n_nhop = 0; 644 } else { 645 /* Use it only if it is valid. */ 646 if (on_net(n->n_nhop, 647 aifp->int_net, aifp->int_mask) 648 && check_dst(n->n_nhop)) { 649 gate = n->n_nhop; 650 } else { 651 msglim(&bad_nhop, FROM_NADDR, 652 "router %s to %s" 653 " has bad next hop %s", 654 naddr_ntoa(FROM_NADDR), 655 naddr_ntoa(dst), 656 naddr_ntoa(n->n_nhop)); 657 n->n_nhop = 0; 658 } 659 } 660 } 661 662 if (rip->rip_vers == RIPv1 663 || 0 == (mask = ntohl(n->n_mask))) { 664 mask = ripv1_mask_host(dst,aifp); 665 } else if ((ntohl(dst) & ~mask) != 0) { 666 msglim(&bad_mask, FROM_NADDR, 667 "router %s sent bad netmask" 668 " %#lx with %s", 669 naddr_ntoa(FROM_NADDR), 670 (u_long)mask, 671 naddr_ntoa(dst)); 672 continue; 673 } 674 if (rip->rip_vers == RIPv1) 675 n->n_tag = 0; 676 677 /* Adjust metric according to incoming interface.. 678 */ 679 n->n_metric += (aifp->int_metric 680 + aifp->int_adj_inmetric); 681 if (n->n_metric > HOPCNT_INFINITY) 682 n->n_metric = HOPCNT_INFINITY; 683 684 /* Should we trust this route from this router? */ 685 if (tg && (tn = tg->tgate_nets)->mask != 0) { 686 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 687 if (on_net(dst, tn->net, tn->mask) 688 && tn->mask <= mask) 689 break; 690 } 691 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 692 trace_pkt(" ignored unauthorized %s", 693 addrname(dst,mask,0)); 694 continue; 695 } 696 } 697 698 /* Recognize and ignore a default route we faked 699 * which is being sent back to us by a machine with 700 * broken split-horizon. 701 * Be a little more paranoid than that, and reject 702 * default routes with the same metric we advertised. 703 */ 704 if (aifp->int_d_metric != 0 705 && dst == RIP_DEFAULT 706 && (int)n->n_metric >= aifp->int_d_metric) 707 continue; 708 709 /* We can receive aggregated RIPv2 routes that must 710 * be broken down before they are transmitted by 711 * RIPv1 via an interface on a subnet. 712 * We might also receive the same routes aggregated 713 * via other RIPv2 interfaces. 714 * This could cause duplicate routes to be sent on 715 * the RIPv1 interfaces. "Longest matching variable 716 * length netmasks" lets RIPv2 listeners understand, 717 * but breaking down the aggregated routes for RIPv1 718 * listeners can produce duplicate routes. 719 * 720 * Breaking down aggregated routes here bloats 721 * the daemon table, but does not hurt the kernel 722 * table, since routes are always aggregated for 723 * the kernel. 724 * 725 * Notice that this does not break down network 726 * routes corresponding to subnets. This is part 727 * of the defense against RS_NET_SYN. 728 */ 729 if (have_ripv1_out 730 && (((rt = rtget(dst,mask)) == 0 731 || !(rt->rt_state & RS_NET_SYN))) 732 && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 733 ddst_h = v1_mask & -v1_mask; 734 i = (v1_mask & ~mask)/ddst_h; 735 if (i >= 511) { 736 /* Punt if we would have to generate 737 * an unreasonable number of routes. 738 */ 739 if (TRACECONTENTS) 740 trace_misc("accept %s-->%s as 1" 741 " instead of %d routes", 742 addrname(dst,mask,0), 743 naddr_ntoa(FROM_NADDR), 744 i+1); 745 i = 0; 746 } else { 747 mask = v1_mask; 748 } 749 } else { 750 i = 0; 751 } 752 753 new.rts_gate = gate; 754 new.rts_router = FROM_NADDR; 755 new.rts_metric = n->n_metric; 756 new.rts_tag = n->n_tag; 757 new.rts_time = now.tv_sec; 758 new.rts_ifp = aifp; 759 new.rts_de_ag = i; 760 j = 0; 761 for (;;) { 762 input_route(dst, mask, &new, n); 763 if (++j > i) 764 break; 765 dst = ntohl(dst) + ddst_h; 766 dst = htonl(dst); 767 } 768 } while (++n < lim); 769 break; 770 } 771 #undef FROM_NADDR 772 } 773 774 775 /* Process a single input route. 776 */ 777 static void 778 input_route(naddr dst, /* network order */ 779 naddr mask, 780 struct rt_spare *new, 781 struct netinfo *n) 782 { 783 int i; 784 struct rt_entry *rt; 785 struct rt_spare *rts, *rts0; 786 struct interface *ifp1; 787 788 789 /* See if the other guy is telling us to send our packets to him. 790 * Sometimes network routes arrive over a point-to-point link for 791 * the network containing the address(es) of the link. 792 * 793 * If our interface is broken, switch to using the other guy. 794 */ 795 ifp1 = ifwithaddr(dst, 1, 1); 796 if (ifp1 != 0 797 && (!(ifp1->int_state & IS_BROKE) 798 || (ifp1->int_state & IS_PASSIVE))) 799 return; 800 801 /* Look for the route in our table. 802 */ 803 rt = rtget(dst, mask); 804 805 /* Consider adding the route if we do not already have it. 806 */ 807 if (rt == 0) { 808 /* Ignore unknown routes being poisoned. 809 */ 810 if (new->rts_metric == HOPCNT_INFINITY) 811 return; 812 813 /* Ignore the route if it points to us */ 814 if (n->n_nhop != 0 815 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 816 return; 817 818 /* If something has not gone crazy and tried to fill 819 * our memory, accept the new route. 820 */ 821 if (total_routes < MAX_ROUTES) 822 rtadd(dst, mask, 0, new); 823 return; 824 } 825 826 /* We already know about the route. Consider this update. 827 * 828 * If (rt->rt_state & RS_NET_SYN), then this route 829 * is the same as a network route we have inferred 830 * for subnets we know, in order to tell RIPv1 routers 831 * about the subnets. 832 * 833 * It is impossible to tell if the route is coming 834 * from a distant RIPv2 router with the standard 835 * netmask because that router knows about the entire 836 * network, or if it is a round-about echo of a 837 * synthetic, RIPv1 network route of our own. 838 * The worst is that both kinds of routes might be 839 * received, and the bad one might have the smaller 840 * metric. Partly solve this problem by never 841 * aggregating into such a route. Also keep it 842 * around as long as the interface exists. 843 */ 844 845 rts0 = rt->rt_spares; 846 for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 847 if (rts->rts_router == new->rts_router) 848 break; 849 /* Note the worst slot to reuse, 850 * other than the current slot. 851 */ 852 if (rts0 == rt->rt_spares 853 || BETTER_LINK(rt, rts0, rts)) 854 rts0 = rts; 855 } 856 if (i != 0) { 857 /* Found a route from the router already in the table. 858 */ 859 860 /* If the new route is a route broken down from an 861 * aggregated route, and if the previous route is either 862 * not a broken down route or was broken down from a finer 863 * netmask, and if the previous route is current, 864 * then forget this one. 865 */ 866 if (new->rts_de_ag > rts->rts_de_ag 867 && now_stale <= rts->rts_time) 868 return; 869 870 /* Keep poisoned routes around only long enough to pass 871 * the poison on. Use a new timestamp for good routes. 872 */ 873 if (rts->rts_metric == HOPCNT_INFINITY 874 && new->rts_metric == HOPCNT_INFINITY) 875 new->rts_time = rts->rts_time; 876 877 /* If this is an update for the router we currently prefer, 878 * then note it. 879 */ 880 if (i == NUM_SPARES) { 881 rtchange(rt, rt->rt_state, new, 0); 882 /* If the route got worse, check for something better. 883 */ 884 if (new->rts_metric > rts->rts_metric) 885 rtswitch(rt, 0); 886 return; 887 } 888 889 /* This is an update for a spare route. 890 * Finished if the route is unchanged. 891 */ 892 if (rts->rts_gate == new->rts_gate 893 && rts->rts_metric == new->rts_metric 894 && rts->rts_tag == new->rts_tag) { 895 trace_upslot(rt, rts, new); 896 *rts = *new; 897 return; 898 } 899 /* Forget it if it has gone bad. 900 */ 901 if (new->rts_metric == HOPCNT_INFINITY) { 902 rts_delete(rt, rts); 903 return; 904 } 905 906 } else { 907 /* The update is for a route we know about, 908 * but not from a familiar router. 909 * 910 * Ignore the route if it points to us. 911 */ 912 if (n->n_nhop != 0 913 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 914 return; 915 916 /* the loop above set rts0=worst spare */ 917 rts = rts0; 918 919 /* Save the route as a spare only if it has 920 * a better metric than our worst spare. 921 * This also ignores poisoned routes (those 922 * received with metric HOPCNT_INFINITY). 923 */ 924 if (new->rts_metric >= rts->rts_metric) 925 return; 926 } 927 928 trace_upslot(rt, rts, new); 929 *rts = *new; 930 931 /* try to switch to a better route */ 932 rtswitch(rt, rts); 933 } 934 935 936 static int /* 0 if bad */ 937 ck_passwd(struct interface *aifp, 938 struct rip *rip, 939 void *lim, 940 naddr from, 941 struct msg_limit *use_authp) 942 { 943 # define NA (rip->rip_auths) 944 struct netauth *na2; 945 struct auth *ap; 946 MD5_CTX md5_ctx; 947 u_char hash[RIP_AUTH_PW_LEN]; 948 int i, len; 949 950 951 if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 952 msglim(use_authp, from, "missing password from %s", 953 naddr_ntoa(from)); 954 return 0; 955 } 956 957 /* accept any current (+/- 24 hours) password 958 */ 959 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 960 if (ap->type != NA->a_type 961 || (u_long)ap->start > (u_long)clk.tv_sec+DAY 962 || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 963 continue; 964 965 if (NA->a_type == RIP_AUTH_PW) { 966 if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 967 return 1; 968 969 } else { 970 /* accept MD5 secret with the right key ID 971 */ 972 if (NA->au.a_md5.md5_keyid != ap->keyid) 973 continue; 974 975 len = ntohs(NA->au.a_md5.md5_pkt_len); 976 if ((len-sizeof(*rip)) % sizeof(*NA) != 0 977 || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 978 msglim(use_authp, from, 979 "wrong MD5 RIPv2 packet length of %d" 980 " instead of %d from %s", 981 len, (int)((char *)lim-(char *)rip 982 -sizeof(*NA)), 983 naddr_ntoa(from)); 984 return 0; 985 } 986 na2 = (struct netauth *)((char *)rip+len); 987 988 /* Given a good hash value, these are not security 989 * problems so be generous and accept the routes, 990 * after complaining. 991 */ 992 if (TRACEPACKETS) { 993 if (NA->au.a_md5.md5_auth_len 994 != RIP_AUTH_MD5_HASH_LEN) 995 msglim(use_authp, from, 996 "unknown MD5 RIPv2 auth len %#x" 997 " instead of %#lx from %s", 998 NA->au.a_md5.md5_auth_len, 999 (unsigned long) RIP_AUTH_MD5_HASH_LEN, 1000 naddr_ntoa(from)); 1001 if (na2->a_family != RIP_AF_AUTH) 1002 msglim(use_authp, from, 1003 "unknown MD5 RIPv2 family %#x" 1004 " instead of %#x from %s", 1005 na2->a_family, RIP_AF_AUTH, 1006 naddr_ntoa(from)); 1007 if (na2->a_type != ntohs(1)) 1008 msglim(use_authp, from, 1009 "MD5 RIPv2 hash has %#x" 1010 " instead of %#x from %s", 1011 na2->a_type, ntohs(1), 1012 naddr_ntoa(from)); 1013 } 1014 1015 MD5Init(&md5_ctx); 1016 MD5Update(&md5_ctx, (u_char *)rip, 1017 len + RIP_AUTH_MD5_HASH_XTRA); 1018 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_KEY_LEN); 1019 MD5Final(hash, &md5_ctx); 1020 if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 1021 return 1; 1022 } 1023 } 1024 1025 msglim(use_authp, from, "bad password from %s", 1026 naddr_ntoa(from)); 1027 return 0; 1028 #undef NA 1029 } 1030
Indexes created Sat Sep 20 22:09:52 GMT 2025