1 /* 2 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 * 5 * Copyright (c) 1983, 1988, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgment: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD: src/sbin/routed/input.c,v 1.9 2001/06/06 20:52:30 phk Exp $ 37 */ 38 39 #include "defs.h" 40 #include <md5.h> 41 42 /* 43 * The size of the control buffer passed to recvmsg() used to receive 44 * ancillary data. 45 */ 46 #define CONTROL_BUFSIZE 1024 47 48 static void input(struct sockaddr_in *, struct interface *, struct rip *, int); 49 static boolean_t ck_passwd(struct interface *, struct rip *, uint8_t *, 50 in_addr_t, struct msg_limit *); 51 52 53 /* 54 * Find the interface which received the given message. 55 */ 56 struct interface * 57 receiving_interface(struct msghdr *msg, boolean_t findremote) 58 { 59 struct interface *ifp, *ifp1, *ifp2; 60 struct sockaddr_in *from; 61 void *opt; 62 uint_t ifindex; 63 64 from = (struct sockaddr_in *)msg->msg_name; 65 66 /* First see if this packet came from a remote gateway. */ 67 if (findremote && ((ifp = findremoteif(from->sin_addr.s_addr)) != NULL)) 68 return (ifp); 69 70 /* 71 * It did not come from a remote gateway. Determine which 72 * physical interface this packet was received on by 73 * processing the message's ancillary data to find the 74 * IP_RECVIF option we requested. 75 */ 76 if ((opt = find_ancillary(msg, IP_RECVIF)) == NULL) { 77 msglog("unable to retrieve IP_RECVIF"); 78 } else { 79 ifindex = *(uint_t *)opt; 80 if ((ifp = ifwithindex(ifindex, _B_TRUE)) != NULL) { 81 /* Find the best match of the aliases */ 82 ifp2 = NULL; 83 for (ifp1 = ifp; ifp1 != NULL; 84 ifp1 = ifp1->int_ilist.hl_next) { 85 if (ifp1->int_addr == from->sin_addr.s_addr) 86 return (ifp1); 87 if ((ifp2 == NULL || 88 (ifp2->int_state & IS_ALIAS)) && 89 on_net(from->sin_addr.s_addr, ifp1->int_net, 90 ifp1->int_mask)) { 91 ifp2 = ifp1; 92 } 93 } 94 if (ifp2 != NULL) 95 ifp = ifp2; 96 return (ifp); 97 } 98 } 99 100 /* 101 * As a last resort (for some reason, ip didn't give us the 102 * IP_RECVIF index we requested), try to deduce the receiving 103 * interface based on the source address of the packet. 104 */ 105 return (iflookup(from->sin_addr.s_addr)); 106 } 107 108 /* 109 * Process RIP input on rip_sock. Returns 0 for success, -1 for failure. 110 */ 111 int 112 read_rip() 113 { 114 struct sockaddr_in from; 115 struct interface *ifp; 116 int cc; 117 union pkt_buf inbuf; 118 struct msghdr msg; 119 struct iovec iov; 120 uint8_t ancillary_data[CONTROL_BUFSIZE]; 121 122 iov.iov_base = &inbuf; 123 iov.iov_len = sizeof (inbuf); 124 msg.msg_iov = &iov; 125 msg.msg_iovlen = 1; 126 msg.msg_name = &from; 127 msg.msg_control = &ancillary_data; 128 129 for (;;) { 130 msg.msg_namelen = sizeof (from); 131 msg.msg_controllen = sizeof (ancillary_data); 132 cc = recvmsg(rip_sock, &msg, 0); 133 if (cc == 0) 134 return (-1); 135 if (cc < 0) { 136 if (errno == EWOULDBLOCK || errno == EINTR) 137 return (0); 138 LOGERR("recvmsg(rip_sock)"); 139 return (-1); 140 } 141 142 /* 143 * ifp is the interface via which the packet arrived. 144 */ 145 ifp = receiving_interface(&msg, _B_TRUE); 146 147 input(&from, ifp, &inbuf.rip, cc); 148 } 149 } 150 151 152 /* Process a RIP packet */ 153 static void 154 input(struct sockaddr_in *from, /* received from this IP address */ 155 struct interface *ifp, /* interface of incoming socket */ 156 struct rip *rip, 157 int cc) 158 { 159 #define FROM_NADDR from->sin_addr.s_addr 160 static struct msg_limit use_auth, bad_len, bad_mask; 161 static struct msg_limit unk_router, bad_router, bad_nhop; 162 163 struct rt_entry *rt; 164 struct rt_spare new; 165 struct netinfo *n, *lim; 166 struct interface *ifp1; 167 in_addr_t gate, mask, v1_mask, dst, ddst_h = 0; 168 struct auth *ap; 169 struct tgate *tg = NULL; 170 struct tgate_net *tn; 171 int i, j; 172 boolean_t poll_answer = _B_FALSE; /* Set to _B_TRUE if RIPCMD_POLL */ 173 uint16_t rt_state = 0; /* Extra route state to pass to input_route() */ 174 uint8_t metric; 175 176 (void) memset(&new, 0, sizeof (new)); 177 /* Notice when we hear from a remote gateway */ 178 if (ifp != NULL && (ifp->int_state & IS_REMOTE)) 179 ifp->int_act_time = now.tv_sec; 180 181 trace_rip("Recv", "from", from, ifp, rip, cc); 182 183 if (ifp != NULL && (ifp->int_if_flags & IFF_NORTEXCH)) { 184 trace_misc("discard RIP packet received over %s (IFF_NORTEXCH)", 185 ifp->int_name); 186 return; 187 } 188 189 gate = ntohl(FROM_NADDR); 190 if (IN_CLASSD(gate) || (gate >> IN_CLASSA_NSHIFT) == 0) { 191 msglim(&bad_router, FROM_NADDR, "source address %s unusable", 192 naddr_ntoa(FROM_NADDR)); 193 return; 194 } 195 196 if (rip->rip_vers == 0) { 197 msglim(&bad_router, FROM_NADDR, 198 "RIP version 0, cmd %d, packet received from %s", 199 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 200 return; 201 } 202 203 if (rip->rip_vers > RIPv2) { 204 msglim(&bad_router, FROM_NADDR, 205 "Treating RIP version %d packet received from %s as " 206 "version %d", rip->rip_vers, naddr_ntoa(FROM_NADDR), 207 RIPv2); 208 rip->rip_vers = RIPv2; 209 } 210 211 if (cc > (int)OVER_MAXPACKETSIZE) { 212 msglim(&bad_router, FROM_NADDR, 213 "packet at least %d bytes too long received from %s", 214 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 215 } 216 217 n = rip->rip_nets; 218 lim = n + (cc - 4) / sizeof (struct netinfo); 219 220 /* 221 * Notice authentication. 222 * As required by section 5.2 of RFC 2453, discard authenticated 223 * RIPv2 messages, but only if configured for that silliness. 224 * 225 * RIPv2 authentication is lame. Why authenticate queries? 226 * Why should a RIPv2 implementation with authentication disabled 227 * not be able to listen to RIPv2 packets with authentication, while 228 * RIPv1 systems will listen? Crazy! 229 */ 230 if (!auth_ok && rip->rip_vers == RIPv2 && n < lim && 231 n->n_family == RIP_AF_AUTH) { 232 msglim(&use_auth, FROM_NADDR, 233 "RIPv2 message with authentication from %s discarded", 234 naddr_ntoa(FROM_NADDR)); 235 return; 236 } 237 238 switch (rip->rip_cmd) { 239 case RIPCMD_POLL: 240 /* 241 * Similar to RIPCMD_REQUEST, this command is used to 242 * request either a full-table or a set of entries. Both 243 * silent processes and routers can respond to this 244 * command. 245 */ 246 poll_answer = _B_TRUE; 247 /* FALLTHRU */ 248 case RIPCMD_REQUEST: 249 /* Are we talking to ourself or a remote gateway? */ 250 ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); 251 if (ifp1 != NULL) { 252 if (ifp1->int_state & IS_REMOTE) { 253 /* remote gateway */ 254 ifp = ifp1; 255 if (check_remote(ifp)) { 256 ifp->int_act_time = now.tv_sec; 257 if_ok(ifp, "remote ", _B_FALSE); 258 } 259 } else if (from->sin_port == htons(RIP_PORT)) { 260 trace_pkt(" discard our own RIP request"); 261 return; 262 } 263 } 264 265 /* did the request come from a router? */ 266 if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { 267 /* 268 * yes, ignore the request if RIP is off so that 269 * the router does not depend on us. 270 */ 271 if (ripout_interfaces == 0 || 272 (ifp != NULL && (IS_RIP_OUT_OFF(ifp->int_state) || 273 !IS_IFF_ROUTING(ifp->int_if_flags)))) { 274 trace_pkt(" discard request while RIP off"); 275 return; 276 } 277 } 278 279 /* 280 * According to RFC 2453 section 5.2, we should ignore 281 * unauthenticated queries when authentication is 282 * configured. That is too silly to bother with. Sheesh! 283 * Are forwarding tables supposed to be secret even though 284 * a bad guy can infer them with test traffic? RIP is 285 * still the most common router-discovery protocol, so 286 * hosts need to send queries that will be answered. What 287 * about `rtquery`? Maybe on firewalls you'd care, but not 288 * enough to give up the diagnostic facilities of remote 289 * probing. 290 */ 291 292 if (n >= lim) { 293 msglim(&bad_len, FROM_NADDR, "empty request from %s", 294 naddr_ntoa(FROM_NADDR)); 295 return; 296 } 297 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 298 msglim(&bad_len, FROM_NADDR, 299 "request of bad length (%d) from %s", 300 cc, naddr_ntoa(FROM_NADDR)); 301 } 302 303 if (rip->rip_vers == RIPv2 && (ifp == NULL || 304 (ifp->int_state & IS_NO_RIPV1_OUT))) { 305 v12buf.buf->rip_vers = RIPv2; 306 /* 307 * If we have a secret but it is a cleartext secret, 308 * do not disclose our secret unless the other guy 309 * already knows it. 310 */ 311 ap = find_auth(ifp); 312 if (ap != NULL && 313 (ulong_t)ap->end < (ulong_t)clk.tv_sec) { 314 /* 315 * Don't authenticate incoming packets 316 * using an expired key. 317 */ 318 msglim(&use_auth, FROM_NADDR, 319 "%s attempting to authenticate using " 320 "an expired password.", 321 naddr_ntoa(FROM_NADDR)); 322 ap = NULL; 323 } 324 if (ap != NULL && ap->type == RIP_AUTH_PW && 325 (n->n_family != RIP_AF_AUTH || 326 !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, 327 &use_auth))) 328 ap = NULL; 329 } else { 330 v12buf.buf->rip_vers = RIPv1; 331 ap = NULL; 332 } 333 clr_ws_buf(&v12buf, ap); 334 335 do { 336 n->n_metric = ntohl(n->n_metric); 337 338 /* 339 * A single entry with family RIP_AF_UNSPEC and 340 * metric HOPCNT_INFINITY means "all routes". 341 * We respond to routers only if we are acting 342 * as a supplier, or to anyone other than a router 343 * (i.e. a query). 344 */ 345 if (n->n_family == RIP_AF_UNSPEC && 346 n->n_metric == HOPCNT_INFINITY) { 347 /* 348 * Answer a full-table query from a utility 349 * program with all we know. 350 */ 351 if (poll_answer || 352 (from->sin_port != htons(RIP_PORT))) { 353 supply(from, ifp, OUT_QUERY, 0, 354 rip->rip_vers, ap != NULL); 355 return; 356 } 357 358 /* 359 * A router is trying to prime its tables. 360 * Filter the answer in the same way 361 * broadcasts are filtered. 362 * 363 * Only answer a router if we are a supplier 364 * to keep an unwary host that is just starting 365 * from picking us as a router. 366 */ 367 if (ifp == NULL) { 368 trace_pkt("ignore distant router"); 369 return; 370 } 371 if (IS_RIP_OFF(ifp->int_state) || 372 !should_supply(ifp)) { 373 trace_pkt("ignore; not supplying"); 374 return; 375 } 376 377 /* 378 * Do not answer a RIPv1 router if 379 * we are sending RIPv2. But do offer 380 * poor man's router discovery. 381 */ 382 if ((ifp->int_state & IS_NO_RIPV1_OUT) && 383 rip->rip_vers == RIPv1) { 384 if (!(ifp->int_state & IS_PM_RDISC)) { 385 trace_pkt("ignore; sending " 386 "RIPv2"); 387 return; 388 } 389 390 v12buf.n->n_family = RIP_AF_INET; 391 v12buf.n->n_dst = RIP_DEFAULT; 392 metric = ifp->int_d_metric; 393 if (NULL != 394 (rt = rtget(RIP_DEFAULT, 0))) 395 metric = MIN(metric, 396 (rt->rt_metric + 1)); 397 v12buf.n->n_metric = htonl(metric); 398 v12buf.n++; 399 break; 400 } 401 402 /* 403 * Respond with RIPv1 instead of RIPv2 if 404 * that is what we are broadcasting on the 405 * interface to keep the remote router from 406 * getting the wrong initial idea of the 407 * routes we send. 408 */ 409 supply(from, ifp, OUT_UNICAST, 0, 410 (ifp->int_state & IS_NO_RIPV1_OUT) 411 ? RIPv2 : RIPv1, 412 ap != NULL); 413 return; 414 } 415 416 /* Ignore authentication */ 417 if (n->n_family == RIP_AF_AUTH) 418 continue; 419 420 if (n->n_family != RIP_AF_INET) { 421 msglim(&bad_router, FROM_NADDR, 422 "request from %s for unsupported" 423 " (af %d) %s", 424 naddr_ntoa(FROM_NADDR), 425 ntohs(n->n_family), 426 naddr_ntoa(n->n_dst)); 427 return; 428 } 429 430 /* We are being asked about a specific destination. */ 431 v12buf.n->n_dst = dst = n->n_dst; 432 v12buf.n->n_family = RIP_AF_INET; 433 if (!check_dst(dst)) { 434 msglim(&bad_router, FROM_NADDR, 435 "bad queried destination %s from %s", 436 naddr_ntoa(dst), 437 naddr_ntoa(FROM_NADDR)); 438 v12buf.n->n_metric = HOPCNT_INFINITY; 439 goto rte_done; 440 } 441 442 /* decide what mask was intended */ 443 if (rip->rip_vers == RIPv1 || 444 0 == (mask = ntohl(n->n_mask)) || 445 0 != (ntohl(dst) & ~mask)) 446 mask = ripv1_mask_host(dst, ifp); 447 448 /* 449 * Try to find the answer. If we don't have an 450 * explicit route for the destination, use the best 451 * route to the destination. 452 */ 453 rt = rtget(dst, mask); 454 if (rt == NULL && dst != RIP_DEFAULT) 455 rt = rtfind(n->n_dst); 456 457 if (v12buf.buf->rip_vers != RIPv1) 458 v12buf.n->n_mask = htonl(mask); 459 if (rt == NULL) { 460 /* we do not have the answer */ 461 v12buf.n->n_metric = HOPCNT_INFINITY; 462 goto rte_done; 463 } 464 465 /* 466 * we have the answer, so compute the right metric 467 * and next hop. 468 */ 469 v12buf.n->n_metric = rt->rt_metric + 1; 470 if (v12buf.n->n_metric > HOPCNT_INFINITY) 471 v12buf.n->n_metric = HOPCNT_INFINITY; 472 if (v12buf.buf->rip_vers != RIPv1) { 473 v12buf.n->n_tag = rt->rt_tag; 474 if (ifp != NULL && 475 on_net(rt->rt_gate, ifp->int_net, 476 ifp->int_mask) && 477 rt->rt_gate != ifp->int_addr) 478 v12buf.n->n_nhop = rt->rt_gate; 479 } 480 rte_done: 481 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 482 483 /* 484 * Stop paying attention if we fill the output buffer. 485 */ 486 if (++v12buf.n >= v12buf.lim) 487 break; 488 } while (++n < lim); 489 490 /* 491 * If our response is authenticated with md5, complete the 492 * md5 computation. 493 */ 494 if (ap != NULL && ap->type == RIP_AUTH_MD5) 495 end_md5_auth(&v12buf, ap); 496 497 /* 498 * Diagnostic programs make specific requests 499 * from ports other than 520. Log other types 500 * of specific requests as suspicious. 501 */ 502 if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { 503 writelog(LOG_WARNING, 504 "Received suspicious request from %s port %d", 505 naddr_ntoa(FROM_NADDR), RIP_PORT); 506 } 507 if (poll_answer || (from->sin_port != htons(RIP_PORT))) { 508 /* query */ 509 (void) output(OUT_QUERY, from, ifp, v12buf.buf, 510 ((char *)v12buf.n - (char *)v12buf.buf)); 511 } else { 512 (void) output(OUT_UNICAST, from, ifp, 513 v12buf.buf, ((char *)v12buf.n - 514 (char *)v12buf.buf)); 515 } 516 return; 517 518 case RIPCMD_TRACEON: 519 case RIPCMD_TRACEOFF: 520 /* 521 * Notice that trace messages are turned off for all possible 522 * abuse if PATH_TRACE is undefined in pathnames.h. 523 * Notice also that because of the way the trace file is 524 * handled in trace.c, no abuse is plausible even if 525 * PATH_TRACE is defined. 526 * 527 * First verify message came from a privileged port. 528 */ 529 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 530 trace_pkt("trace command from untrusted port %d on %s", 531 ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); 532 return; 533 } 534 if (ifp == NULL || !remote_address_ok(ifp, FROM_NADDR)) { 535 /* 536 * Use a message here to warn about strange 537 * messages from remote systems. 538 */ 539 msglim(&bad_router, FROM_NADDR, 540 "trace command from non-local host %s", 541 naddr_ntoa(FROM_NADDR)); 542 return; 543 } 544 if (ifp->int_state & IS_DISTRUST) { 545 tg = tgates; 546 while (tg->tgate_addr != FROM_NADDR) { 547 tg = tg->tgate_next; 548 if (tg == NULL) { 549 trace_pkt("trace command from " 550 "untrusted host %s", 551 naddr_ntoa(FROM_NADDR)); 552 return; 553 } 554 } 555 } 556 if (ifp->int_auth[0].type != RIP_AUTH_NONE) { 557 /* 558 * Technically, it would be fairly easy to add 559 * standard authentication to the existing 560 * trace commands -- just bracket the payload 561 * with the authentication information. 562 * However, the tracing message behavior 563 * itself is marginal enough that we don't 564 * actually care. Just discard if 565 * authentication is needed. 566 */ 567 trace_pkt("trace command unauthenticated from %s", 568 naddr_ntoa(FROM_NADDR)); 569 return; 570 } 571 if (rip->rip_cmd == RIPCMD_TRACEON) { 572 rip->rip_tracefile[cc-4] = '\0'; 573 set_tracefile(rip->rip_tracefile, 574 "trace command: %s\n", 0); 575 } else { 576 trace_off("tracing turned off by %s", 577 naddr_ntoa(FROM_NADDR)); 578 } 579 return; 580 581 case RIPCMD_RESPONSE: 582 if (ifp != NULL && (ifp->int_if_flags & IFF_NOXMIT)) { 583 trace_misc("discard RIP response received over %s " 584 "(IFF_NOXMIT)", ifp->int_name); 585 return; 586 } 587 588 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 589 msglim(&bad_len, FROM_NADDR, 590 "response of bad length (%d) from %s", 591 cc, naddr_ntoa(FROM_NADDR)); 592 } 593 594 if ((gate >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || 595 IN_LINKLOCAL(gate)) { 596 msglim(&bad_router, FROM_NADDR, 597 "discard RIP response from bad source address %s", 598 naddr_ntoa(FROM_NADDR)); 599 return; 600 } 601 602 /* verify message came from a router */ 603 if (from->sin_port != htons(RIP_PORT)) { 604 msglim(&bad_router, FROM_NADDR, 605 " discard RIP response from unknown port" 606 " %d on host %s", ntohs(from->sin_port), 607 naddr_ntoa(FROM_NADDR)); 608 return; 609 } 610 611 if (!rip_enabled) { 612 trace_pkt(" discard response while RIP off"); 613 return; 614 } 615 616 /* Are we talking to ourself or a remote gateway? */ 617 ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); 618 if (ifp1 != NULL) { 619 if (ifp1->int_state & IS_REMOTE) { 620 /* remote gateway */ 621 ifp = ifp1; 622 if (check_remote(ifp)) { 623 ifp->int_act_time = now.tv_sec; 624 if_ok(ifp, "remote ", _B_FALSE); 625 } 626 } else { 627 trace_pkt(" discard our own RIP response"); 628 return; 629 } 630 } else { 631 /* 632 * If it's not a remote gateway, then the 633 * remote address *must* be directly 634 * connected. Make sure that it is. 635 */ 636 if (ifp != NULL && 637 !remote_address_ok(ifp, FROM_NADDR)) { 638 msglim(&bad_router, FROM_NADDR, 639 "discard RIP response; source %s not on " 640 "interface %s", naddr_ntoa(FROM_NADDR), 641 ifp->int_name); 642 return; 643 } 644 } 645 646 /* 647 * Accept routing packets from routers directly connected 648 * via broadcast or point-to-point networks, and from 649 * those listed in /etc/gateways. 650 */ 651 if (ifp == NULL) { 652 msglim(&unk_router, FROM_NADDR, 653 " discard response from %s" 654 " via unexpected interface", 655 naddr_ntoa(FROM_NADDR)); 656 return; 657 } 658 659 if (IS_RIP_IN_OFF(ifp->int_state)) { 660 trace_pkt(" discard RIPv%d response" 661 " via disabled interface %s", 662 rip->rip_vers, ifp->int_name); 663 return; 664 } 665 666 if (n >= lim) { 667 msglim(&bad_len, FROM_NADDR, "empty response from %s", 668 naddr_ntoa(FROM_NADDR)); 669 return; 670 } 671 672 if (((ifp->int_state & IS_NO_RIPV1_IN) && 673 rip->rip_vers == RIPv1) || 674 ((ifp->int_state & IS_NO_RIPV2_IN) && 675 rip->rip_vers != RIPv1)) { 676 trace_pkt(" discard RIPv%d response", 677 rip->rip_vers); 678 return; 679 } 680 681 /* 682 * Continue to listen to routes via broken interfaces 683 * which might be declared IS_BROKE because of 684 * device-driver idiosyncracies, but might otherwise 685 * be perfectly healthy. 686 */ 687 if (ifp->int_state & IS_BROKE) { 688 trace_pkt("response via broken interface %s", 689 ifp->int_name); 690 } 691 692 /* 693 * If the interface cares, ignore bad routers. 694 * Trace but do not log this problem, because where it 695 * happens, it happens frequently. 696 */ 697 if (ifp->int_state & IS_DISTRUST) { 698 tg = tgates; 699 while (tg->tgate_addr != FROM_NADDR) { 700 tg = tg->tgate_next; 701 if (tg == NULL) { 702 trace_pkt(" discard RIP response" 703 " from untrusted router %s", 704 naddr_ntoa(FROM_NADDR)); 705 return; 706 } 707 } 708 } 709 710 /* 711 * Authenticate the packet if we have a secret. 712 * If we do not have any secrets, ignore the error in 713 * RFC 1723 and accept it regardless. 714 */ 715 if (ifp->int_auth[0].type != RIP_AUTH_NONE && 716 rip->rip_vers != RIPv1 && 717 !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, &use_auth)) 718 return; 719 720 /* 721 * Do this only if we're supplying routes to *nobody*. 722 */ 723 if (!should_supply(NULL) && save_space) { 724 /* 725 * "-S" option. Instead of entering all routes, 726 * only enter a default route for the sender of 727 * this RESPONSE message 728 */ 729 730 /* Should we trust this route from this router? */ 731 if (tg != NULL && tg->tgate_nets->mask != 0) { 732 trace_pkt(" ignored unauthorized %s", 733 addrname(RIP_DEFAULT, 0, 0)); 734 break; 735 } 736 737 new.rts_gate = FROM_NADDR; 738 new.rts_router = FROM_NADDR; 739 new.rts_metric = HOPCNT_INFINITY-1; 740 new.rts_tag = n->n_tag; 741 new.rts_time = now.tv_sec; 742 new.rts_ifp = ifp; 743 new.rts_de_ag = 0; 744 new.rts_origin = RO_RIP; 745 /* 746 * Add the newly generated default route, but don't 747 * propagate the madness. Treat it the same way as 748 * default routes learned from Router Discovery. 749 */ 750 input_route(RIP_DEFAULT, 0, &new, n, RS_NOPROPAGATE); 751 return; 752 } 753 754 if (!IS_IFF_ROUTING(ifp->int_if_flags)) { 755 /* 756 * We don't want to propagate routes which would 757 * result in a black-hole. 758 */ 759 rt_state = RS_NOPROPAGATE; 760 } 761 762 do { 763 if (n->n_family == RIP_AF_AUTH) 764 continue; 765 766 n->n_metric = ntohl(n->n_metric); 767 dst = n->n_dst; 768 if (n->n_family != RIP_AF_INET && 769 (n->n_family != RIP_AF_UNSPEC || 770 dst != RIP_DEFAULT)) { 771 msglim(&bad_router, FROM_NADDR, 772 "route from %s to unsupported" 773 " address family=%d destination=%s", 774 naddr_ntoa(FROM_NADDR), n->n_family, 775 naddr_ntoa(dst)); 776 continue; 777 } 778 if (!check_dst(dst)) { 779 msglim(&bad_router, FROM_NADDR, 780 "bad destination %s from %s", 781 naddr_ntoa(dst), 782 naddr_ntoa(FROM_NADDR)); 783 continue; 784 } 785 if (n->n_metric == 0 || n->n_metric > HOPCNT_INFINITY) { 786 msglim(&bad_router, FROM_NADDR, 787 "bad metric %d from %s" 788 " for destination %s", 789 n->n_metric, naddr_ntoa(FROM_NADDR), 790 naddr_ntoa(dst)); 791 continue; 792 } 793 794 /* 795 * Notice the next-hop. 796 */ 797 gate = FROM_NADDR; 798 if (n->n_nhop != 0) { 799 if (rip->rip_vers == RIPv1) { 800 n->n_nhop = 0; 801 } else { 802 /* Use it only if it is valid. */ 803 if (on_net(n->n_nhop, 804 ifp->int_net, ifp->int_mask) && 805 check_dst(n->n_nhop)) { 806 gate = n->n_nhop; 807 } else { 808 msglim(&bad_nhop, 809 FROM_NADDR, 810 "router %s to %s" 811 " has bad next hop %s", 812 naddr_ntoa(FROM_NADDR), 813 naddr_ntoa(dst), 814 naddr_ntoa(n->n_nhop)); 815 n->n_nhop = 0; 816 } 817 } 818 } 819 820 if (rip->rip_vers == RIPv1 || 821 0 == (mask = ntohl(n->n_mask))) { 822 mask = ripv1_mask_host(dst, ifp); 823 } else if ((ntohl(dst) & ~mask) != 0) { 824 msglim(&bad_mask, FROM_NADDR, 825 "router %s sent bad netmask %s with %s", 826 naddr_ntoa(FROM_NADDR), 827 naddr_ntoa(htonl(mask)), 828 naddr_ntoa(dst)); 829 continue; 830 } 831 832 if (mask == HOST_MASK && 833 (ifp->int_state & IS_NO_HOST)) { 834 trace_pkt(" ignored host route %s", 835 addrname(dst, mask, 0)); 836 continue; 837 } 838 839 if (rip->rip_vers == RIPv1) 840 n->n_tag = 0; 841 842 /* 843 * Adjust metric according to incoming interface cost. 844 * We intentionally don't drop incoming routes with 845 * metric 15 on the floor even though they will 846 * not be advertised to other routers. We can use 847 * such routes locally, resulting in a network with 848 * a maximum width of 15 hops rather than 14. 849 */ 850 n->n_metric += ifp->int_metric; 851 if (n->n_metric > HOPCNT_INFINITY) 852 n->n_metric = HOPCNT_INFINITY; 853 854 /* 855 * Should we trust this route from this router? 856 */ 857 if (tg != NULL && (tn = tg->tgate_nets)->mask != 0) { 858 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 859 if (on_net(dst, tn->net, tn->mask) && 860 tn->mask <= mask) 861 break; 862 } 863 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 864 trace_pkt(" ignored unauthorized %s", 865 addrname(dst, mask, 0)); 866 continue; 867 } 868 } 869 870 /* 871 * Recognize and ignore a default route we faked 872 * which is being sent back to us by a machine with 873 * broken split-horizon. Be a little more paranoid 874 * than that, and reject default routes with the 875 * same metric we advertised. 876 */ 877 if (ifp->int_d_metric != 0 && dst == RIP_DEFAULT && 878 n->n_metric >= ifp->int_d_metric) 879 continue; 880 881 /* 882 * We can receive aggregated RIPv2 routes that must 883 * be broken down before they are transmitted by 884 * RIPv1 via an interface on a subnet. We might 885 * also receive the same routes aggregated via 886 * other RIPv2 interfaces. This could cause 887 * duplicate routes to be sent on the RIPv1 888 * interfaces. "Longest matching variable length 889 * netmasks" lets RIPv2 listeners understand, but 890 * breaking down the aggregated routes for RIPv1 891 * listeners can produce duplicate routes. 892 * 893 * Breaking down aggregated routes here bloats the 894 * daemon table, but does not hurt the kernel 895 * table, since routes are always aggregated for 896 * the kernel. 897 * 898 * Notice that this does not break down network 899 * routes corresponding to subnets. This is part of 900 * the defense against RS_NET_SYN. 901 */ 902 if (have_ripv1_out && 903 (((rt = rtget(dst, mask)) == NULL || 904 !(rt->rt_state & RS_NET_SYN))) && 905 (v1_mask = ripv1_mask_net(dst, 0)) > mask) { 906 /* Get least significant set bit */ 907 ddst_h = v1_mask & -v1_mask; 908 i = (v1_mask & ~mask)/ddst_h; 909 /* 910 * If you're going to make 512 or more 911 * routes, then that's just too many. The 912 * reason here is that breaking an old 913 * class B into /24 allocations is common 914 * enough that allowing for the creation of 915 * at least 256 deaggregated routes is 916 * good. The next power of 2 is 512. 917 */ 918 if (i >= 511) { 919 /* 920 * Punt if we would have to 921 * generate an unreasonable number 922 * of routes. 923 */ 924 if (TRACECONTENTS) 925 trace_misc("accept %s-->%s as 1" 926 " instead of %d routes", 927 addrname(dst, mask, 0), 928 naddr_ntoa(FROM_NADDR), 929 i + 1); 930 i = 0; 931 } else { 932 mask = v1_mask; 933 } 934 } else { 935 i = 0; 936 } 937 938 new.rts_gate = gate; 939 new.rts_router = FROM_NADDR; 940 new.rts_metric = n->n_metric; 941 new.rts_tag = n->n_tag; 942 new.rts_time = now.tv_sec; 943 new.rts_ifp = ifp; 944 new.rts_de_ag = i; 945 new.rts_origin = RO_RIP; 946 j = 0; 947 for (;;) { 948 input_route(dst, mask, &new, n, rt_state); 949 if (++j > i) 950 break; 951 dst = htonl(ntohl(dst) + ddst_h); 952 } 953 } while (++n < lim); 954 return; 955 case RIPCMD_POLLENTRY: 956 /* 957 * With this command one can request a single entry. 958 * Both silent processes and routers can respond to this 959 * command 960 */ 961 962 if (n >= lim) { 963 msglim(&bad_len, FROM_NADDR, "empty request from %s", 964 naddr_ntoa(FROM_NADDR)); 965 return; 966 } 967 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 968 msglim(&bad_len, FROM_NADDR, 969 "request of bad length (%d) from %s", 970 cc, naddr_ntoa(FROM_NADDR)); 971 } 972 973 if (rip->rip_vers == RIPv2 && (ifp == NULL || 974 (ifp->int_state & IS_NO_RIPV1_OUT))) { 975 v12buf.buf->rip_vers = RIPv2; 976 } else { 977 v12buf.buf->rip_vers = RIPv1; 978 } 979 /* Dont bother with md5 authentication with POLLENTRY */ 980 ap = NULL; 981 clr_ws_buf(&v12buf, ap); 982 983 n->n_metric = ntohl(n->n_metric); 984 985 if (n->n_family != RIP_AF_INET) { 986 msglim(&bad_router, FROM_NADDR, 987 "POLLENTRY request from %s for unsupported" 988 " (af %d) %s", 989 naddr_ntoa(FROM_NADDR), 990 ntohs(n->n_family), 991 naddr_ntoa(n->n_dst)); 992 return; 993 } 994 995 /* We are being asked about a specific destination. */ 996 v12buf.n->n_dst = dst = n->n_dst; 997 v12buf.n->n_family = RIP_AF_INET; 998 if (!check_dst(dst)) { 999 msglim(&bad_router, FROM_NADDR, 1000 "bad queried destination %s from %s", 1001 naddr_ntoa(dst), 1002 naddr_ntoa(FROM_NADDR)); 1003 v12buf.n->n_metric = HOPCNT_INFINITY; 1004 goto pollentry_done; 1005 } 1006 1007 /* decide what mask was intended */ 1008 if (rip->rip_vers == RIPv1 || 1009 0 == (mask = ntohl(n->n_mask)) || 1010 0 != (ntohl(dst) & ~mask)) 1011 mask = ripv1_mask_host(dst, ifp); 1012 1013 /* try to find the answer */ 1014 rt = rtget(dst, mask); 1015 if (rt == NULL && dst != RIP_DEFAULT) 1016 rt = rtfind(n->n_dst); 1017 1018 if (v12buf.buf->rip_vers != RIPv1) 1019 v12buf.n->n_mask = htonl(mask); 1020 if (rt == NULL) { 1021 /* we do not have the answer */ 1022 v12buf.n->n_metric = HOPCNT_INFINITY; 1023 goto pollentry_done; 1024 } 1025 1026 1027 /* 1028 * we have the answer, so compute the right metric and next 1029 * hop. 1030 */ 1031 v12buf.n->n_metric = rt->rt_metric + 1; 1032 if (v12buf.n->n_metric > HOPCNT_INFINITY) 1033 v12buf.n->n_metric = HOPCNT_INFINITY; 1034 if (v12buf.buf->rip_vers != RIPv1) { 1035 v12buf.n->n_tag = rt->rt_tag; 1036 if (ifp != NULL && 1037 on_net(rt->rt_gate, ifp->int_net, ifp->int_mask) && 1038 rt->rt_gate != ifp->int_addr) 1039 v12buf.n->n_nhop = rt->rt_gate; 1040 } 1041 pollentry_done: 1042 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 1043 1044 /* 1045 * Send the answer about specific routes. 1046 */ 1047 (void) output(OUT_QUERY, from, ifp, v12buf.buf, 1048 ((char *)v12buf.n - (char *)v12buf.buf)); 1049 break; 1050 } 1051 #undef FROM_NADDR 1052 } 1053 1054 1055 /* 1056 * Process a single input route. 1057 */ 1058 void 1059 input_route(in_addr_t dst, /* network order */ 1060 in_addr_t mask, 1061 struct rt_spare *new, 1062 struct netinfo *n, 1063 uint16_t rt_state) 1064 { 1065 int i; 1066 struct rt_entry *rt; 1067 struct rt_spare *rts, *rts0; 1068 struct interface *ifp1; 1069 struct rt_spare *ptr; 1070 size_t ptrsize; 1071 1072 /* 1073 * See if we can already get there by a working interface. Ignore 1074 * if so. 1075 */ 1076 ifp1 = ifwithaddr(dst, _B_TRUE, _B_FALSE); 1077 if (ifp1 != NULL && (ifp1->int_state & IS_PASSIVE)) 1078 return; 1079 1080 /* 1081 * Look for the route in our table. 1082 */ 1083 rt = rtget(dst, mask); 1084 1085 /* Consider adding the route if we do not already have it. */ 1086 if (rt == NULL) { 1087 /* Ignore unknown routes being poisoned. */ 1088 if (new->rts_metric == HOPCNT_INFINITY) 1089 return; 1090 1091 /* Ignore the route if it points to us */ 1092 if (n != NULL && n->n_nhop != 0 && 1093 NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) 1094 return; 1095 1096 /* 1097 * If something has not gone crazy and tried to fill 1098 * our memory, accept the new route. 1099 */ 1100 rtadd(dst, mask, rt_state, new); 1101 return; 1102 } 1103 1104 /* 1105 * We already know about the route. Consider this update. 1106 * 1107 * If (rt->rt_state & RS_NET_SYN), then this route 1108 * is the same as a network route we have inferred 1109 * for subnets we know, in order to tell RIPv1 routers 1110 * about the subnets. 1111 * 1112 * It is impossible to tell if the route is coming 1113 * from a distant RIPv2 router with the standard 1114 * netmask because that router knows about the entire 1115 * network, or if it is a round-about echo of a 1116 * synthetic, RIPv1 network route of our own. 1117 * The worst is that both kinds of routes might be 1118 * received, and the bad one might have the smaller 1119 * metric. Partly solve this problem by never 1120 * aggregating into such a route. Also keep it 1121 * around as long as the interface exists. 1122 */ 1123 1124 rts0 = rt->rt_spares; 1125 for (rts = rts0, i = rt->rt_num_spares; i != 0; i--, rts++) { 1126 if (rts->rts_router == new->rts_router) 1127 break; 1128 /* 1129 * Note the worst slot to reuse, 1130 * other than the current slot. 1131 */ 1132 if (BETTER_LINK(rt, rts0, rts)) 1133 rts0 = rts; 1134 } 1135 if (i != 0) { 1136 /* 1137 * Found a route from the router already in the table. 1138 */ 1139 1140 /* 1141 * If the new route is a route broken down from an 1142 * aggregated route, and if the previous route is either 1143 * not a broken down route or was broken down from a finer 1144 * netmask, and if the previous route is current, 1145 * then forget this one. 1146 */ 1147 if (new->rts_de_ag > rts->rts_de_ag && 1148 now_stale <= rts->rts_time) 1149 return; 1150 1151 /* 1152 * Keep poisoned routes around only long enough to pass 1153 * the poison on. Use a new timestamp for good routes. 1154 */ 1155 if (rts->rts_metric == HOPCNT_INFINITY && 1156 new->rts_metric == HOPCNT_INFINITY) 1157 new->rts_time = rts->rts_time; 1158 1159 /* 1160 * If this is an update for the router we currently prefer, 1161 * then note it. 1162 */ 1163 if (i == rt->rt_num_spares) { 1164 uint8_t old_metric = rts->rts_metric; 1165 1166 rtchange(rt, rt->rt_state | rt_state, new, 0); 1167 /* 1168 * If the route got worse, check for something better. 1169 */ 1170 if (new->rts_metric != old_metric) 1171 rtswitch(rt, 0); 1172 return; 1173 } 1174 1175 /* 1176 * This is an update for a spare route. 1177 * Finished if the route is unchanged. 1178 */ 1179 if (rts->rts_gate == new->rts_gate && 1180 rts->rts_metric == new->rts_metric && 1181 rts->rts_tag == new->rts_tag) { 1182 if ((rt->rt_dst == RIP_DEFAULT) && 1183 (rts->rts_ifp != new->rts_ifp)) 1184 trace_misc("input_route update for spare"); 1185 trace_upslot(rt, rts, new); 1186 *rts = *new; 1187 return; 1188 } 1189 1190 /* 1191 * Forget it if it has gone bad. 1192 */ 1193 if (new->rts_metric == HOPCNT_INFINITY) { 1194 rts_delete(rt, rts); 1195 return; 1196 } 1197 1198 } else { 1199 /* 1200 * The update is for a route we know about, 1201 * but not from a familiar router. 1202 * 1203 * Ignore the route if it points to us. 1204 */ 1205 if (n != NULL && n->n_nhop != 0 && 1206 NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) 1207 return; 1208 1209 /* the loop above set rts0=worst spare */ 1210 if (rts0->rts_metric < HOPCNT_INFINITY) { 1211 ptrsize = (rt->rt_num_spares + SPARE_INC) * 1212 sizeof (struct rt_spare); 1213 ptr = realloc(rt->rt_spares, ptrsize); 1214 if (ptr != NULL) { 1215 1216 rt->rt_spares = ptr; 1217 rts0 = &rt->rt_spares[rt->rt_num_spares]; 1218 (void) memset(rts0, 0, 1219 SPARE_INC * sizeof (struct rt_spare)); 1220 rt->rt_num_spares += SPARE_INC; 1221 for (rts = rts0, i = SPARE_INC; 1222 i != 0; i--, rts++) 1223 rts->rts_metric = HOPCNT_INFINITY; 1224 } 1225 } 1226 rts = rts0; 1227 1228 /* 1229 * Save the route as a spare only if it has 1230 * a better metric than our worst spare. 1231 * This also ignores poisoned routes (those 1232 * received with metric HOPCNT_INFINITY). 1233 */ 1234 if (new->rts_metric >= rts->rts_metric) 1235 return; 1236 } 1237 trace_upslot(rt, rts, new); 1238 *rts = *new; 1239 1240 /* try to switch to a better route */ 1241 rtswitch(rt, rts); 1242 } 1243 1244 /* 1245 * Recorded information about peer's MD5 sequence numbers. This is 1246 * used to validate that received sequence numbers are in 1247 * non-decreasing order as per the RFC. 1248 */ 1249 struct peer_hash { 1250 struct peer_hash *ph_next; 1251 in_addr_t ph_addr; 1252 time_t ph_heard; 1253 uint32_t ph_seqno; 1254 }; 1255 1256 static struct peer_hash **peer_hashes; 1257 static int ph_index; 1258 static int ph_num_peers; 1259 1260 /* 1261 * Get a peer_hash structure from the hash of known peers. Create a 1262 * new one if not found. Returns NULL on unrecoverable allocation 1263 * failure. 1264 */ 1265 static struct peer_hash * 1266 get_peer_info(in_addr_t from) 1267 { 1268 struct peer_hash *php; 1269 struct peer_hash *pnhp; 1270 struct peer_hash **ph_pp; 1271 struct peer_hash **ph2_pp; 1272 struct peer_hash **ph3_pp; 1273 int i; 1274 static uint_t failed_count; 1275 1276 if (peer_hashes == NULL) { 1277 peer_hashes = calloc(hash_table_sizes[0], 1278 sizeof (peer_hashes[0])); 1279 if (peer_hashes == NULL) { 1280 if (++failed_count % 100 == 1) 1281 msglog("no memory for peer hash"); 1282 return (NULL); 1283 } 1284 } 1285 /* Search for peer in existing hash table */ 1286 ph_pp = peer_hashes + (from % hash_table_sizes[ph_index]); 1287 for (php = ph_pp[0]; php != NULL; php = php->ph_next) { 1288 if (php->ph_addr == from) 1289 return (php); 1290 } 1291 /* 1292 * Not found; we need to add this peer to the table. If there 1293 * are already too many peers, then try to expand the table 1294 * first. It's not a big deal if we can't expand the table 1295 * right now due to memory constraints. We'll try again 1296 * later. 1297 */ 1298 if (ph_num_peers >= hash_table_sizes[ph_index] * 5 && 1299 hash_table_sizes[ph_index + 1] != 0 && 1300 (ph_pp = calloc(hash_table_sizes[ph_index + 1], 1301 sizeof (peer_hashes[0]))) != NULL) { 1302 ph2_pp = peer_hashes; 1303 for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { 1304 for (php = ph2_pp[i]; php != NULL; php = pnhp) { 1305 pnhp = php->ph_next; 1306 ph3_pp = ph_pp + (php->ph_addr % 1307 hash_table_sizes[ph_index + 1]); 1308 php->ph_next = ph3_pp[0]; 1309 ph3_pp[0] = php; 1310 } 1311 } 1312 ph_index++; 1313 free(peer_hashes); 1314 peer_hashes = ph_pp; 1315 ph_pp += from % hash_table_sizes[ph_index]; 1316 } 1317 php = calloc(sizeof (*php), 1); 1318 if (php == NULL) { 1319 if (++failed_count % 100 == 1) 1320 msglog("no memory for peer hash entry"); 1321 } else { 1322 php->ph_addr = from; 1323 php->ph_heard = now.tv_sec; 1324 php->ph_next = ph_pp[0]; 1325 ph_pp[0] = php; 1326 ph_num_peers++; 1327 } 1328 return (php); 1329 } 1330 1331 /* 1332 * Age out entries in the peer table. This is called every time we do 1333 * a normal 30 second broadcast. 1334 */ 1335 void 1336 age_peer_info(void) 1337 { 1338 struct peer_hash *php; 1339 struct peer_hash *next_ph; 1340 struct peer_hash *prev_ph; 1341 struct peer_hash **ph_pp; 1342 int i; 1343 1344 /* 1345 * Scan through the list and remove peers that should not 1346 * still have valid authenticated entries in the routing 1347 * table. 1348 */ 1349 if ((ph_pp = peer_hashes) == NULL || ph_num_peers == 0) 1350 return; 1351 for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { 1352 prev_ph = NULL; 1353 for (php = ph_pp[i]; php != NULL; php = next_ph) { 1354 next_ph = php->ph_next; 1355 if (php->ph_heard <= now_expire) { 1356 if (prev_ph == NULL) 1357 ph_pp[i] = next_ph; 1358 else 1359 prev_ph->ph_next = next_ph; 1360 free(php); 1361 if (--ph_num_peers == 0) 1362 return; 1363 } else { 1364 prev_ph = php; 1365 } 1366 } 1367 } 1368 } 1369 1370 static boolean_t /* _B_FALSE if bad, _B_TRUE if good */ 1371 ck_passwd(struct interface *aifp, 1372 struct rip *rip, 1373 uint8_t *lim, 1374 in_addr_t from, 1375 struct msg_limit *use_authp) 1376 { 1377 #define NA (rip->rip_auths) 1378 struct netauth *na2; 1379 struct auth *ap; 1380 MD5_CTX md5_ctx; 1381 uchar_t hash[RIP_AUTH_PW_LEN]; 1382 int i, len; 1383 struct peer_hash *php; 1384 uint32_t seqno; 1385 1386 if ((uint8_t *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 1387 msglim(use_authp, from, "missing auth data from %s", 1388 naddr_ntoa(from)); 1389 return (_B_FALSE); 1390 } 1391 1392 /* 1393 * Validate sequence number on RIPv2 responses using keyed MD5 1394 * authentication per RFC 2082 section 3.2.2. Note that if we 1395 * can't locate the peer information (due to transient 1396 * allocation problems), then we don't do the test. Also note 1397 * that we assume that all sequence numbers 0x80000000 or more 1398 * away are "less than." 1399 * 1400 * We intentionally violate RFC 2082 with respect to one case: 1401 * restablishing contact. The RFC says that you should 1402 * continue to ignore old sequence numbers in this case but 1403 * make a special allowance for 0. This is extremely foolish. 1404 * The problem is that if the router has crashed, it's 1405 * entirely possible that either we'll miss sequence zero (or 1406 * that it might not even send it!) or that the peer doesn't 1407 * remember what it last used for a sequence number. In 1408 * either case, we'll create a failure state that persists 1409 * until the sequence number happens to advance past the last 1410 * one we saw. This is bad because it means that we may have 1411 * to wait until the router has been up for at least as long 1412 * as it was last time before we even pay attention to it. 1413 * Meanwhile, other routers may listen to it if they hadn't 1414 * seen it before (i.e., if they crashed in the meantime). 1415 * This means -- perversely -- that stable systems that stay 1416 * "up" for a long time pay a penalty for doing so. 1417 */ 1418 if (rip->rip_cmd == RIPCMD_RESPONSE && NA->a_type == RIP_AUTH_MD5 && 1419 (php = get_peer_info(from)) != NULL) { 1420 /* 1421 * If the entry that we find has been updated 1422 * recently enough that the routes are known 1423 * to still be good, but the sequence number 1424 * looks bad, then discard the packet. 1425 */ 1426 seqno = ntohl(NA->au.a_md5.md5_seqno); 1427 if (php->ph_heard > now_expire && php->ph_seqno != 0 && 1428 (seqno == 0 || ((seqno - php->ph_seqno) & 0x80000000ul))) { 1429 msglim(use_authp, from, 1430 "discarding sequence %x (older than %x)", 1431 (unsigned)seqno, (unsigned)php->ph_seqno); 1432 return (_B_FALSE); 1433 } 1434 php->ph_heard = now.tv_sec; 1435 php->ph_seqno = seqno; 1436 } 1437 1438 /* 1439 * accept any current (+/- 24 hours) password 1440 */ 1441 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 1442 if (ap->type != NA->a_type || 1443 (ulong_t)ap->start > (ulong_t)clk.tv_sec+DAY || 1444 (ulong_t)ap->end+DAY < (ulong_t)clk.tv_sec) 1445 continue; 1446 1447 if (NA->a_type == RIP_AUTH_PW) { 1448 if (0 == memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 1449 return (_B_TRUE); 1450 1451 } else { 1452 /* 1453 * accept MD5 secret with the right key ID 1454 */ 1455 if (NA->au.a_md5.md5_keyid != ap->keyid) 1456 continue; 1457 1458 len = ntohs(NA->au.a_md5.md5_pkt_len); 1459 if ((len - sizeof (*rip)) % sizeof (*NA) != 0 || 1460 len > (lim - (uint8_t *)rip - sizeof (*NA))) { 1461 msglim(use_authp, from, 1462 "wrong MD5 RIPv2 packet length of %d" 1463 " instead of %d from %s", 1464 len, lim - (uint8_t *)rip - sizeof (*NA), 1465 naddr_ntoa(from)); 1466 return (_B_FALSE); 1467 } 1468 na2 = (struct netauth *)(rip->rip_nets + 1469 (len - 4) / sizeof (struct netinfo)); 1470 1471 /* 1472 * Given a good hash value, these are not security 1473 * problems so be generous and accept the routes, 1474 * after complaining. 1475 */ 1476 if (TRACEPACKETS) { 1477 if (NA->au.a_md5.md5_auth_len != 1478 RIP_AUTH_MD5_LEN) 1479 msglim(use_authp, from, 1480 "unknown MD5 RIPv2 auth len %#x" 1481 " instead of %#x from %s", 1482 NA->au.a_md5.md5_auth_len, 1483 RIP_AUTH_MD5_LEN, 1484 naddr_ntoa(from)); 1485 if (na2->a_family != RIP_AF_AUTH) 1486 msglim(use_authp, from, 1487 "unknown MD5 RIPv2 family %#x" 1488 " instead of %#x from %s", 1489 na2->a_family, RIP_AF_AUTH, 1490 naddr_ntoa(from)); 1491 if (na2->a_type != RIP_AUTH_TRAILER) 1492 msglim(use_authp, from, 1493 "MD5 RIPv2 hash has %#x" 1494 " instead of %#x from %s", 1495 ntohs(na2->a_type), 1496 ntohs(RIP_AUTH_TRAILER), 1497 naddr_ntoa(from)); 1498 } 1499 1500 MD5Init(&md5_ctx); 1501 /* 1502 * len+4 to include auth trailer's family/type in 1503 * MD5 sum 1504 */ 1505 MD5Update(&md5_ctx, (uchar_t *)rip, len + 4); 1506 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); 1507 MD5Final(hash, &md5_ctx); 1508 if (0 == memcmp(hash, na2->au.au_pw, sizeof (hash))) 1509 return (_B_TRUE); 1510 } 1511 } 1512 1513 msglim(use_authp, from, "bad auth data from %s", 1514 naddr_ntoa(from)); 1515 return (_B_FALSE); 1516 #undef NA 1517 } 1518