1 /* 2 * Copyright 2006 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 #pragma ident "%Z%%M% %I% %E% SMI" 40 41 #include "defs.h" 42 #include <md5.h> 43 44 /* 45 * The size of the control buffer passed to recvmsg() used to receive 46 * ancillary data. 47 */ 48 #define CONTROL_BUFSIZE 1024 49 50 static void input(struct sockaddr_in *, struct interface *, struct rip *, int); 51 static boolean_t ck_passwd(struct interface *, struct rip *, uint8_t *, 52 in_addr_t, struct msg_limit *); 53 54 55 /* 56 * Find the interface which received the given message. 57 */ 58 struct interface * 59 receiving_interface(struct msghdr *msg, boolean_t findremote) 60 { 61 struct interface *ifp, *ifp1, *ifp2; 62 struct sockaddr_in *from; 63 void *opt; 64 uint_t ifindex; 65 66 from = (struct sockaddr_in *)msg->msg_name; 67 68 /* First see if this packet came from a remote gateway. */ 69 if (findremote && ((ifp = findremoteif(from->sin_addr.s_addr)) != NULL)) 70 return (ifp); 71 72 /* 73 * It did not come from a remote gateway. Determine which 74 * physical interface this packet was received on by 75 * processing the message's ancillary data to find the 76 * IP_RECVIF option we requested. 77 */ 78 if ((opt = find_ancillary(msg, IP_RECVIF)) == NULL) { 79 msglog("unable to retrieve IP_RECVIF"); 80 } else { 81 ifindex = *(uint_t *)opt; 82 if ((ifp = ifwithindex(ifindex, _B_TRUE)) != NULL) { 83 /* Find the best match of the aliases */ 84 ifp2 = NULL; 85 for (ifp1 = ifp; ifp1 != NULL; 86 ifp1 = ifp1->int_ilist.hl_next) { 87 if (ifp1->int_addr == from->sin_addr.s_addr) 88 return (ifp1); 89 if ((ifp2 == NULL || 90 (ifp2->int_state & IS_ALIAS)) && 91 on_net(from->sin_addr.s_addr, ifp1->int_net, 92 ifp1->int_mask)) 93 ifp2 = ifp1; 94 } 95 if (ifp2 != NULL) 96 ifp = ifp2; 97 return (ifp); 98 } 99 } 100 101 /* 102 * As a last resort (for some reason, ip didn't give us the 103 * IP_RECVIF index we requested), try to deduce the receiving 104 * interface based on the source address of the packet. 105 */ 106 ifp = iflookup(from->sin_addr.s_addr); 107 if (ifp != NULL && ifp->int_phys != NULL) { 108 ifp = ifwithname(ifp->int_phys->phyi_name); 109 } 110 return (ifp); 111 } 112 113 /* 114 * Process RIP input on rip_sock. Returns 0 for success, -1 for failure. 115 */ 116 int 117 read_rip() 118 { 119 struct sockaddr_in from; 120 struct interface *ifp; 121 int cc; 122 union pkt_buf inbuf; 123 struct msghdr msg; 124 struct iovec iov; 125 uint8_t ancillary_data[CONTROL_BUFSIZE]; 126 127 iov.iov_base = &inbuf; 128 iov.iov_len = sizeof (inbuf); 129 msg.msg_iov = &iov; 130 msg.msg_iovlen = 1; 131 msg.msg_name = &from; 132 msg.msg_control = &ancillary_data; 133 134 for (;;) { 135 msg.msg_namelen = sizeof (from); 136 msg.msg_controllen = sizeof (ancillary_data); 137 cc = recvmsg(rip_sock, &msg, 0); 138 if (cc == 0) 139 return (-1); 140 if (cc < 0) { 141 if (errno == EWOULDBLOCK || errno == EINTR) 142 return (0); 143 LOGERR("recvmsg(rip_sock)"); 144 return (-1); 145 } 146 147 /* 148 * ifp is the interface via which the packet arrived. 149 */ 150 ifp = receiving_interface(&msg, _B_TRUE); 151 152 input(&from, ifp, &inbuf.rip, cc); 153 } 154 } 155 156 157 /* Process a RIP packet */ 158 static void 159 input(struct sockaddr_in *from, /* received from this IP address */ 160 struct interface *ifp, /* interface of incoming socket */ 161 struct rip *rip, 162 int cc) 163 { 164 #define FROM_NADDR from->sin_addr.s_addr 165 static struct msg_limit use_auth, bad_len, bad_mask; 166 static struct msg_limit unk_router, bad_router, bad_nhop; 167 168 struct rt_entry *rt; 169 struct rt_spare new; 170 struct netinfo *n, *lim; 171 struct interface *ifp1; 172 in_addr_t gate, mask, v1_mask, dst, ddst_h = 0; 173 struct auth *ap; 174 struct tgate *tg = NULL; 175 struct tgate_net *tn; 176 int i, j; 177 boolean_t poll_answer = _B_FALSE; /* Set to _B_TRUE if RIPCMD_POLL */ 178 uint16_t rt_state = 0; /* Extra route state to pass to input_route() */ 179 uint8_t metric; 180 181 (void) memset(&new, 0, sizeof (new)); 182 /* Notice when we hear from a remote gateway */ 183 if (ifp != NULL && (ifp->int_state & IS_REMOTE)) 184 ifp->int_act_time = now.tv_sec; 185 186 trace_rip("Recv", "from", from, ifp, rip, cc); 187 188 if (ifp != NULL && (ifp->int_if_flags & IFF_NORTEXCH)) { 189 trace_misc("discard RIP packet received over %s (IFF_NORTEXCH)", 190 ifp->int_name); 191 return; 192 } 193 194 gate = ntohl(FROM_NADDR); 195 if (IN_EXPERIMENTAL(gate) || (gate >> IN_CLASSA_NSHIFT) == 0) { 196 msglim(&bad_router, FROM_NADDR, "source address %s unusable", 197 naddr_ntoa(FROM_NADDR)); 198 return; 199 } 200 201 if (rip->rip_vers == 0) { 202 msglim(&bad_router, FROM_NADDR, 203 "RIP version 0, cmd %d, packet received from %s", 204 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 205 return; 206 } 207 208 if (rip->rip_vers > RIPv2) { 209 msglim(&bad_router, FROM_NADDR, 210 "Treating RIP version %d packet received from %s as " 211 "version %d", rip->rip_vers, naddr_ntoa(FROM_NADDR), 212 RIPv2); 213 rip->rip_vers = RIPv2; 214 } 215 216 if (cc > (int)OVER_MAXPACKETSIZE) { 217 msglim(&bad_router, FROM_NADDR, 218 "packet at least %d bytes too long received from %s", 219 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 220 } 221 222 n = rip->rip_nets; 223 lim = n + (cc - 4) / sizeof (struct netinfo); 224 225 /* 226 * Notice authentication. 227 * As required by section 5.2 of RFC 2453, discard authenticated 228 * RIPv2 messages, but only if configured for that silliness. 229 * 230 * RIPv2 authentication is lame. Why authenticate queries? 231 * Why should a RIPv2 implementation with authentication disabled 232 * not be able to listen to RIPv2 packets with authentication, while 233 * RIPv1 systems will listen? Crazy! 234 */ 235 if (!auth_ok && rip->rip_vers == RIPv2 && n < lim && 236 n->n_family == RIP_AF_AUTH) { 237 msglim(&use_auth, FROM_NADDR, 238 "RIPv2 message with authentication from %s discarded", 239 naddr_ntoa(FROM_NADDR)); 240 return; 241 } 242 243 switch (rip->rip_cmd) { 244 case RIPCMD_POLL: 245 /* 246 * Similar to RIPCMD_REQUEST, this command is used to 247 * request either a full-table or a set of entries. Both 248 * silent processes and routers can respond to this 249 * command. 250 */ 251 poll_answer = _B_TRUE; 252 /* FALLTHRU */ 253 case RIPCMD_REQUEST: 254 /* Are we talking to ourself or a remote gateway? */ 255 ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); 256 if (ifp1 != NULL) { 257 if (ifp1->int_state & IS_REMOTE) { 258 /* remote gateway */ 259 ifp = ifp1; 260 if (check_remote(ifp)) { 261 ifp->int_act_time = now.tv_sec; 262 if_ok(ifp, "remote ", _B_FALSE); 263 } 264 } else if (from->sin_port == htons(RIP_PORT)) { 265 trace_pkt(" discard our own RIP request"); 266 return; 267 } 268 } 269 270 /* did the request come from a router? */ 271 if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { 272 /* 273 * yes, ignore the request if RIP is off so that 274 * the router does not depend on us. 275 */ 276 if (ripout_interfaces == 0 || 277 (ifp != NULL && (IS_RIP_OUT_OFF(ifp->int_state) || 278 !IS_IFF_ROUTING(ifp->int_if_flags)))) { 279 trace_pkt(" discard request while RIP off"); 280 return; 281 } 282 } 283 284 /* 285 * According to RFC 2453 section 5.2, we should ignore 286 * unauthenticated queries when authentication is 287 * configured. That is too silly to bother with. Sheesh! 288 * Are forwarding tables supposed to be secret even though 289 * a bad guy can infer them with test traffic? RIP is 290 * still the most common router-discovery protocol, so 291 * hosts need to send queries that will be answered. What 292 * about `rtquery`? Maybe on firewalls you'd care, but not 293 * enough to give up the diagnostic facilities of remote 294 * probing. 295 */ 296 297 if (n >= lim) { 298 msglim(&bad_len, FROM_NADDR, "empty request from %s", 299 naddr_ntoa(FROM_NADDR)); 300 return; 301 } 302 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 303 msglim(&bad_len, FROM_NADDR, 304 "request of bad length (%d) from %s", 305 cc, naddr_ntoa(FROM_NADDR)); 306 } 307 308 if (rip->rip_vers == RIPv2 && (ifp == NULL || 309 (ifp->int_state & IS_NO_RIPV1_OUT))) { 310 v12buf.buf->rip_vers = RIPv2; 311 /* 312 * If we have a secret but it is a cleartext secret, 313 * do not disclose our secret unless the other guy 314 * already knows it. 315 */ 316 ap = find_auth(ifp); 317 if (ap != NULL && 318 (ulong_t)ap->end < (ulong_t)clk.tv_sec) { 319 /* 320 * Don't authenticate incoming packets 321 * using an expired key. 322 */ 323 msglim(&use_auth, FROM_NADDR, 324 "%s attempting to authenticate using " 325 "an expired password.", 326 naddr_ntoa(FROM_NADDR)); 327 ap = NULL; 328 } 329 if (ap != NULL && ap->type == RIP_AUTH_PW && 330 (n->n_family != RIP_AF_AUTH || 331 !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, 332 &use_auth))) 333 ap = NULL; 334 } else { 335 v12buf.buf->rip_vers = RIPv1; 336 ap = NULL; 337 } 338 clr_ws_buf(&v12buf, ap); 339 340 do { 341 n->n_metric = ntohl(n->n_metric); 342 343 /* 344 * A single entry with family RIP_AF_UNSPEC and 345 * metric HOPCNT_INFINITY means "all routes". 346 * We respond to routers only if we are acting 347 * as a supplier, or to anyone other than a router 348 * (i.e. a query). 349 */ 350 if (n->n_family == RIP_AF_UNSPEC && 351 n->n_metric == HOPCNT_INFINITY) { 352 /* 353 * Answer a full-table query from a utility 354 * program with all we know. 355 */ 356 if (poll_answer || 357 (from->sin_port != htons(RIP_PORT))) { 358 supply(from, ifp, OUT_QUERY, 0, 359 rip->rip_vers, ap != NULL); 360 return; 361 } 362 363 /* 364 * A router is trying to prime its tables. 365 * Filter the answer in the same way 366 * broadcasts are filtered. 367 * 368 * Only answer a router if we are a supplier 369 * to keep an unwary host that is just starting 370 * from picking us as a router. 371 */ 372 if (ifp == NULL) { 373 trace_pkt("ignore distant router"); 374 return; 375 } 376 if (IS_RIP_OFF(ifp->int_state) || 377 !should_supply(ifp)) { 378 trace_pkt("ignore; not supplying"); 379 return; 380 } 381 382 /* 383 * Do not answer a RIPv1 router if 384 * we are sending RIPv2. But do offer 385 * poor man's router discovery. 386 */ 387 if ((ifp->int_state & IS_NO_RIPV1_OUT) && 388 rip->rip_vers == RIPv1) { 389 if (!(ifp->int_state & IS_PM_RDISC)) { 390 trace_pkt("ignore; sending RIPv2"); 391 return; 392 } 393 394 v12buf.n->n_family = RIP_AF_INET; 395 v12buf.n->n_dst = RIP_DEFAULT; 396 metric = ifp->int_d_metric; 397 if (NULL != 398 (rt = rtget(RIP_DEFAULT, 0))) 399 metric = MIN(metric, 400 (rt->rt_metric + 1)); 401 v12buf.n->n_metric = htonl(metric); 402 v12buf.n++; 403 break; 404 } 405 406 /* 407 * Respond with RIPv1 instead of RIPv2 if 408 * that is what we are broadcasting on the 409 * interface to keep the remote router from 410 * getting the wrong initial idea of the 411 * routes we send. 412 */ 413 supply(from, ifp, OUT_UNICAST, 0, 414 (ifp->int_state & IS_NO_RIPV1_OUT) 415 ? RIPv2 : RIPv1, 416 ap != NULL); 417 return; 418 } 419 420 /* Ignore authentication */ 421 if (n->n_family == RIP_AF_AUTH) 422 continue; 423 424 if (n->n_family != RIP_AF_INET) { 425 msglim(&bad_router, FROM_NADDR, 426 "request from %s for unsupported" 427 " (af %d) %s", 428 naddr_ntoa(FROM_NADDR), 429 ntohs(n->n_family), 430 naddr_ntoa(n->n_dst)); 431 return; 432 } 433 434 /* We are being asked about a specific destination. */ 435 v12buf.n->n_dst = dst = n->n_dst; 436 v12buf.n->n_family = RIP_AF_INET; 437 if (!check_dst(dst)) { 438 msglim(&bad_router, FROM_NADDR, 439 "bad queried destination %s from %s", 440 naddr_ntoa(dst), 441 naddr_ntoa(FROM_NADDR)); 442 v12buf.n->n_metric = HOPCNT_INFINITY; 443 goto rte_done; 444 } 445 446 /* decide what mask was intended */ 447 if (rip->rip_vers == RIPv1 || 448 0 == (mask = ntohl(n->n_mask)) || 449 0 != (ntohl(dst) & ~mask)) 450 mask = ripv1_mask_host(dst, ifp); 451 452 /* 453 * Try to find the answer. If we don't have an 454 * explicit route for the destination, use the best 455 * route to the destination. 456 */ 457 rt = rtget(dst, mask); 458 if (rt == NULL && dst != RIP_DEFAULT) 459 rt = rtfind(n->n_dst); 460 461 if (v12buf.buf->rip_vers != RIPv1) 462 v12buf.n->n_mask = htonl(mask); 463 if (rt == NULL) { 464 /* we do not have the answer */ 465 v12buf.n->n_metric = HOPCNT_INFINITY; 466 goto rte_done; 467 } 468 469 /* 470 * we have the answer, so compute the right metric 471 * and next hop. 472 */ 473 v12buf.n->n_metric = rt->rt_metric + 1; 474 if (v12buf.n->n_metric > HOPCNT_INFINITY) 475 v12buf.n->n_metric = HOPCNT_INFINITY; 476 if (v12buf.buf->rip_vers != RIPv1) { 477 v12buf.n->n_tag = rt->rt_tag; 478 if (ifp != NULL && 479 on_net(rt->rt_gate, ifp->int_net, 480 ifp->int_mask) && 481 rt->rt_gate != ifp->int_addr) 482 v12buf.n->n_nhop = rt->rt_gate; 483 } 484 rte_done: 485 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 486 487 /* 488 * Stop paying attention if we fill the output buffer. 489 */ 490 if (++v12buf.n >= v12buf.lim) 491 break; 492 } while (++n < lim); 493 494 /* 495 * If our response is authenticated with md5, complete the 496 * md5 computation. 497 */ 498 if (ap != NULL && ap->type == RIP_AUTH_MD5) 499 end_md5_auth(&v12buf, ap); 500 501 /* 502 * Diagnostic programs make specific requests 503 * from ports other than 520. Log other types 504 * of specific requests as suspicious. 505 */ 506 if (!poll_answer && (from->sin_port == htons(RIP_PORT))) { 507 writelog(LOG_WARNING, 508 "Received suspicious request from %s port %d", 509 naddr_ntoa(FROM_NADDR), RIP_PORT); 510 } 511 if (poll_answer || (from->sin_port != htons(RIP_PORT))) { 512 /* query */ 513 (void) output(OUT_QUERY, from, ifp, v12buf.buf, 514 ((char *)v12buf.n - (char *)v12buf.buf)); 515 } else { 516 (void) output(OUT_UNICAST, from, ifp, 517 v12buf.buf, ((char *)v12buf.n - 518 (char *)v12buf.buf)); 519 } 520 return; 521 522 case RIPCMD_TRACEON: 523 case RIPCMD_TRACEOFF: 524 /* 525 * Notice that trace messages are turned off for all possible 526 * abuse if PATH_TRACE is undefined in pathnames.h. 527 * Notice also that because of the way the trace file is 528 * handled in trace.c, no abuse is plausible even if 529 * PATH_TRACE is defined. 530 * 531 * First verify message came from a privileged port. 532 */ 533 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 534 trace_pkt("trace command from untrusted port %d on %s", 535 ntohs(from->sin_port), naddr_ntoa(FROM_NADDR)); 536 return; 537 } 538 if (ifp == NULL || !remote_address_ok(ifp, FROM_NADDR)) { 539 /* 540 * Use a message here to warn about strange 541 * messages from remote systems. 542 */ 543 msglim(&bad_router, FROM_NADDR, 544 "trace command from non-local host %s", 545 naddr_ntoa(FROM_NADDR)); 546 return; 547 } 548 if (ifp->int_state & IS_DISTRUST) { 549 tg = tgates; 550 while (tg->tgate_addr != FROM_NADDR) { 551 tg = tg->tgate_next; 552 if (tg == NULL) { 553 trace_pkt("trace command from " 554 "untrusted host %s", 555 naddr_ntoa(FROM_NADDR)); 556 return; 557 } 558 } 559 } 560 if (ifp->int_auth[0].type != RIP_AUTH_NONE) { 561 /* 562 * Technically, it would be fairly easy to add 563 * standard authentication to the existing 564 * trace commands -- just bracket the payload 565 * with the authentication information. 566 * However, the tracing message behavior 567 * itself is marginal enough that we don't 568 * actually care. Just discard if 569 * authentication is needed. 570 */ 571 trace_pkt("trace command unauthenticated from %s", 572 naddr_ntoa(FROM_NADDR)); 573 return; 574 } 575 if (rip->rip_cmd == RIPCMD_TRACEON) { 576 rip->rip_tracefile[cc-4] = '\0'; 577 set_tracefile(rip->rip_tracefile, 578 "trace command: %s\n", 0); 579 } else { 580 trace_off("tracing turned off by %s", 581 naddr_ntoa(FROM_NADDR)); 582 } 583 return; 584 585 case RIPCMD_RESPONSE: 586 if (ifp != NULL && (ifp->int_if_flags & IFF_NOXMIT)) { 587 trace_misc("discard RIP response received over %s " 588 "(IFF_NOXMIT)", ifp->int_name); 589 return; 590 } 591 592 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 593 msglim(&bad_len, FROM_NADDR, 594 "response of bad length (%d) from %s", 595 cc, naddr_ntoa(FROM_NADDR)); 596 } 597 598 if ((ntohl(FROM_NADDR) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) { 599 msglim(&bad_router, FROM_NADDR, 600 "discard RIP response from bad source address %s", 601 naddr_ntoa(FROM_NADDR)); 602 return; 603 } 604 605 /* verify message came from a router */ 606 if (from->sin_port != htons(RIP_PORT)) { 607 msglim(&bad_router, FROM_NADDR, 608 " discard RIP response from unknown port" 609 " %d on host %s", ntohs(from->sin_port), 610 naddr_ntoa(FROM_NADDR)); 611 return; 612 } 613 614 if (!rip_enabled) { 615 trace_pkt(" discard response while RIP off"); 616 return; 617 } 618 619 /* Are we talking to ourself or a remote gateway? */ 620 ifp1 = ifwithaddr(FROM_NADDR, _B_FALSE, _B_TRUE); 621 if (ifp1 != NULL) { 622 if (ifp1->int_state & IS_REMOTE) { 623 /* remote gateway */ 624 ifp = ifp1; 625 if (check_remote(ifp)) { 626 ifp->int_act_time = now.tv_sec; 627 if_ok(ifp, "remote ", _B_FALSE); 628 } 629 } else { 630 trace_pkt(" discard our own RIP response"); 631 return; 632 } 633 } else { 634 /* 635 * If it's not a remote gateway, then the 636 * remote address *must* be directly 637 * connected. Make sure that it is. 638 */ 639 if (ifp != NULL && 640 !remote_address_ok(ifp, FROM_NADDR)) { 641 msglim(&bad_router, FROM_NADDR, 642 "discard RIP response; source %s not on " 643 "interface %s", naddr_ntoa(FROM_NADDR), 644 ifp->int_name); 645 return; 646 } 647 } 648 649 /* 650 * Accept routing packets from routers directly connected 651 * via broadcast or point-to-point networks, and from 652 * those listed in /etc/gateways. 653 */ 654 if (ifp == NULL) { 655 msglim(&unk_router, FROM_NADDR, 656 " discard response from %s" 657 " via unexpected interface", 658 naddr_ntoa(FROM_NADDR)); 659 return; 660 } 661 662 if (IS_RIP_IN_OFF(ifp->int_state)) { 663 trace_pkt(" discard RIPv%d response" 664 " via disabled interface %s", 665 rip->rip_vers, ifp->int_name); 666 return; 667 } 668 669 if (n >= lim) { 670 msglim(&bad_len, FROM_NADDR, "empty response from %s", 671 naddr_ntoa(FROM_NADDR)); 672 return; 673 } 674 675 if (((ifp->int_state & IS_NO_RIPV1_IN) && 676 rip->rip_vers == RIPv1) || 677 ((ifp->int_state & IS_NO_RIPV2_IN) && 678 rip->rip_vers != RIPv1)) { 679 trace_pkt(" discard RIPv%d response", 680 rip->rip_vers); 681 return; 682 } 683 684 /* 685 * Continue to listen to routes via broken interfaces 686 * which might be declared IS_BROKE because of 687 * device-driver idiosyncracies, but might otherwise 688 * be perfectly healthy. 689 */ 690 if (ifp->int_state & IS_BROKE) { 691 trace_pkt("response via broken interface %s", 692 ifp->int_name); 693 } 694 695 /* 696 * If the interface cares, ignore bad routers. 697 * Trace but do not log this problem, because where it 698 * happens, it happens frequently. 699 */ 700 if (ifp->int_state & IS_DISTRUST) { 701 tg = tgates; 702 while (tg->tgate_addr != FROM_NADDR) { 703 tg = tg->tgate_next; 704 if (tg == NULL) { 705 trace_pkt(" discard RIP response" 706 " from untrusted router %s", 707 naddr_ntoa(FROM_NADDR)); 708 return; 709 } 710 } 711 } 712 713 /* 714 * Authenticate the packet if we have a secret. 715 * If we do not have any secrets, ignore the error in 716 * RFC 1723 and accept it regardless. 717 */ 718 if (ifp->int_auth[0].type != RIP_AUTH_NONE && 719 rip->rip_vers != RIPv1 && 720 !ck_passwd(ifp, rip, (uint8_t *)lim, FROM_NADDR, &use_auth)) 721 return; 722 723 /* 724 * Do this only if we're supplying routes to *nobody*. 725 */ 726 if (!should_supply(NULL) && save_space) { 727 /* 728 * "-S" option. Instead of entering all routes, 729 * only enter a default route for the sender of 730 * this RESPONSE message 731 */ 732 733 /* Should we trust this route from this router? */ 734 if (tg != NULL && tg->tgate_nets->mask != 0) { 735 trace_pkt(" ignored unauthorized %s", 736 addrname(RIP_DEFAULT, 0, 0)); 737 break; 738 } 739 740 new.rts_gate = FROM_NADDR; 741 new.rts_router = FROM_NADDR; 742 new.rts_metric = HOPCNT_INFINITY-1; 743 new.rts_tag = n->n_tag; 744 new.rts_time = now.tv_sec; 745 new.rts_ifp = ifp; 746 new.rts_de_ag = 0; 747 new.rts_origin = RO_RIP; 748 /* 749 * Add the newly generated default route, but don't 750 * propagate the madness. Treat it the same way as 751 * default routes learned from Router Discovery. 752 */ 753 input_route(RIP_DEFAULT, 0, &new, n, RS_NOPROPAGATE); 754 return; 755 } 756 757 if (!IS_IFF_ROUTING(ifp->int_if_flags)) { 758 /* 759 * We don't want to propagate routes which would 760 * result in a black-hole. 761 */ 762 rt_state = RS_NOPROPAGATE; 763 } 764 765 do { 766 if (n->n_family == RIP_AF_AUTH) 767 continue; 768 769 n->n_metric = ntohl(n->n_metric); 770 dst = n->n_dst; 771 if (n->n_family != RIP_AF_INET && 772 (n->n_family != RIP_AF_UNSPEC || 773 dst != RIP_DEFAULT)) { 774 msglim(&bad_router, FROM_NADDR, 775 "route from %s to unsupported" 776 " address family=%d destination=%s", 777 naddr_ntoa(FROM_NADDR), n->n_family, 778 naddr_ntoa(dst)); 779 continue; 780 } 781 if (!check_dst(dst)) { 782 msglim(&bad_router, FROM_NADDR, 783 "bad destination %s from %s", 784 naddr_ntoa(dst), 785 naddr_ntoa(FROM_NADDR)); 786 continue; 787 } 788 if (n->n_metric == 0 || n->n_metric > HOPCNT_INFINITY) { 789 msglim(&bad_router, FROM_NADDR, 790 "bad metric %d from %s" 791 " for destination %s", 792 n->n_metric, naddr_ntoa(FROM_NADDR), 793 naddr_ntoa(dst)); 794 continue; 795 } 796 797 /* 798 * Notice the next-hop. 799 */ 800 gate = FROM_NADDR; 801 if (n->n_nhop != 0) { 802 if (rip->rip_vers == RIPv1) { 803 n->n_nhop = 0; 804 } else { 805 /* Use it only if it is valid. */ 806 if (on_net(n->n_nhop, 807 ifp->int_net, ifp->int_mask) && 808 check_dst(n->n_nhop)) { 809 gate = n->n_nhop; 810 } else { 811 msglim(&bad_nhop, 812 FROM_NADDR, 813 "router %s to %s" 814 " has bad next hop %s", 815 naddr_ntoa(FROM_NADDR), 816 naddr_ntoa(dst), 817 naddr_ntoa(n->n_nhop)); 818 n->n_nhop = 0; 819 } 820 } 821 } 822 823 if (rip->rip_vers == RIPv1 || 824 0 == (mask = ntohl(n->n_mask))) { 825 mask = ripv1_mask_host(dst, ifp); 826 } else if ((ntohl(dst) & ~mask) != 0) { 827 msglim(&bad_mask, FROM_NADDR, 828 "router %s sent bad netmask %s with %s", 829 naddr_ntoa(FROM_NADDR), 830 naddr_ntoa(htonl(mask)), 831 naddr_ntoa(dst)); 832 continue; 833 } 834 835 if (mask == HOST_MASK && 836 (ifp->int_state & IS_NO_HOST)) { 837 trace_pkt(" ignored host route %s", 838 addrname(dst, mask, 0)); 839 continue; 840 } 841 842 if (rip->rip_vers == RIPv1) 843 n->n_tag = 0; 844 845 /* 846 * Adjust metric according to incoming interface cost. 847 * We intentionally don't drop incoming routes with 848 * metric 15 on the floor even though they will 849 * not be advertised to other routers. We can use 850 * such routes locally, resulting in a network with 851 * a maximum width of 15 hops rather than 14. 852 */ 853 n->n_metric += ifp->int_metric; 854 if (n->n_metric > HOPCNT_INFINITY) 855 n->n_metric = HOPCNT_INFINITY; 856 857 /* 858 * Should we trust this route from this router? 859 */ 860 if (tg != NULL && (tn = tg->tgate_nets)->mask != 0) { 861 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 862 if (on_net(dst, tn->net, tn->mask) && 863 tn->mask <= mask) 864 break; 865 } 866 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 867 trace_pkt(" ignored unauthorized %s", 868 addrname(dst, mask, 0)); 869 continue; 870 } 871 } 872 873 /* 874 * Recognize and ignore a default route we faked 875 * which is being sent back to us by a machine with 876 * broken split-horizon. Be a little more paranoid 877 * than that, and reject default routes with the 878 * same metric we advertised. 879 */ 880 if (ifp->int_d_metric != 0 && dst == RIP_DEFAULT && 881 n->n_metric >= ifp->int_d_metric) 882 continue; 883 884 /* 885 * We can receive aggregated RIPv2 routes that must 886 * be broken down before they are transmitted by 887 * RIPv1 via an interface on a subnet. We might 888 * also receive the same routes aggregated via 889 * other RIPv2 interfaces. This could cause 890 * duplicate routes to be sent on the RIPv1 891 * interfaces. "Longest matching variable length 892 * netmasks" lets RIPv2 listeners understand, but 893 * breaking down the aggregated routes for RIPv1 894 * listeners can produce duplicate routes. 895 * 896 * Breaking down aggregated routes here bloats the 897 * daemon table, but does not hurt the kernel 898 * table, since routes are always aggregated for 899 * the kernel. 900 * 901 * Notice that this does not break down network 902 * routes corresponding to subnets. This is part of 903 * the defense against RS_NET_SYN. 904 */ 905 if (have_ripv1_out && 906 (((rt = rtget(dst, mask)) == NULL || 907 !(rt->rt_state & RS_NET_SYN))) && 908 (v1_mask = ripv1_mask_net(dst, 0)) > mask) { 909 /* Get least significant set bit */ 910 ddst_h = v1_mask & -v1_mask; 911 i = (v1_mask & ~mask)/ddst_h; 912 /* 913 * If you're going to make 512 or more 914 * routes, then that's just too many. The 915 * reason here is that breaking an old 916 * class B into /24 allocations is common 917 * enough that allowing for the creation of 918 * at least 256 deaggregated routes is 919 * good. The next power of 2 is 512. 920 */ 921 if (i >= 511) { 922 /* 923 * Punt if we would have to 924 * generate an unreasonable number 925 * of routes. 926 */ 927 if (TRACECONTENTS) 928 trace_misc("accept %s-->%s as 1" 929 " instead of %d routes", 930 addrname(dst, mask, 0), 931 naddr_ntoa(FROM_NADDR), 932 i + 1); 933 i = 0; 934 } else { 935 mask = v1_mask; 936 } 937 } else { 938 i = 0; 939 } 940 941 new.rts_gate = gate; 942 new.rts_router = FROM_NADDR; 943 new.rts_metric = n->n_metric; 944 new.rts_tag = n->n_tag; 945 new.rts_time = now.tv_sec; 946 new.rts_ifp = ifp; 947 new.rts_de_ag = i; 948 new.rts_origin = RO_RIP; 949 j = 0; 950 for (;;) { 951 input_route(dst, mask, &new, n, rt_state); 952 if (++j > i) 953 break; 954 dst = htonl(ntohl(dst) + ddst_h); 955 } 956 } while (++n < lim); 957 return; 958 case RIPCMD_POLLENTRY: 959 /* 960 * With this command one can request a single entry. 961 * Both silent processes and routers can respond to this 962 * command 963 */ 964 965 if (n >= lim) { 966 msglim(&bad_len, FROM_NADDR, "empty request from %s", 967 naddr_ntoa(FROM_NADDR)); 968 return; 969 } 970 if (cc%sizeof (*n) != sizeof (struct rip)%sizeof (*n)) { 971 msglim(&bad_len, FROM_NADDR, 972 "request of bad length (%d) from %s", 973 cc, naddr_ntoa(FROM_NADDR)); 974 } 975 976 if (rip->rip_vers == RIPv2 && (ifp == NULL || 977 (ifp->int_state & IS_NO_RIPV1_OUT))) { 978 v12buf.buf->rip_vers = RIPv2; 979 } else { 980 v12buf.buf->rip_vers = RIPv1; 981 } 982 /* Dont bother with md5 authentication with POLLENTRY */ 983 ap = NULL; 984 clr_ws_buf(&v12buf, ap); 985 986 n->n_metric = ntohl(n->n_metric); 987 988 if (n->n_family != RIP_AF_INET) { 989 msglim(&bad_router, FROM_NADDR, 990 "POLLENTRY request from %s for unsupported" 991 " (af %d) %s", 992 naddr_ntoa(FROM_NADDR), 993 ntohs(n->n_family), 994 naddr_ntoa(n->n_dst)); 995 return; 996 } 997 998 /* We are being asked about a specific destination. */ 999 v12buf.n->n_dst = dst = n->n_dst; 1000 v12buf.n->n_family = RIP_AF_INET; 1001 if (!check_dst(dst)) { 1002 msglim(&bad_router, FROM_NADDR, 1003 "bad queried destination %s from %s", 1004 naddr_ntoa(dst), 1005 naddr_ntoa(FROM_NADDR)); 1006 v12buf.n->n_metric = HOPCNT_INFINITY; 1007 goto pollentry_done; 1008 } 1009 1010 /* decide what mask was intended */ 1011 if (rip->rip_vers == RIPv1 || 1012 0 == (mask = ntohl(n->n_mask)) || 1013 0 != (ntohl(dst) & ~mask)) 1014 mask = ripv1_mask_host(dst, ifp); 1015 1016 /* try to find the answer */ 1017 rt = rtget(dst, mask); 1018 if (rt == NULL && dst != RIP_DEFAULT) 1019 rt = rtfind(n->n_dst); 1020 1021 if (v12buf.buf->rip_vers != RIPv1) 1022 v12buf.n->n_mask = htonl(mask); 1023 if (rt == NULL) { 1024 /* we do not have the answer */ 1025 v12buf.n->n_metric = HOPCNT_INFINITY; 1026 goto pollentry_done; 1027 } 1028 1029 1030 /* 1031 * we have the answer, so compute the right metric and next 1032 * hop. 1033 */ 1034 v12buf.n->n_metric = rt->rt_metric + 1; 1035 if (v12buf.n->n_metric > HOPCNT_INFINITY) 1036 v12buf.n->n_metric = HOPCNT_INFINITY; 1037 if (v12buf.buf->rip_vers != RIPv1) { 1038 v12buf.n->n_tag = rt->rt_tag; 1039 if (ifp != NULL && 1040 on_net(rt->rt_gate, ifp->int_net, ifp->int_mask) && 1041 rt->rt_gate != ifp->int_addr) 1042 v12buf.n->n_nhop = rt->rt_gate; 1043 } 1044 pollentry_done: 1045 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 1046 1047 /* 1048 * Send the answer about specific routes. 1049 */ 1050 (void) output(OUT_QUERY, from, ifp, v12buf.buf, 1051 ((char *)v12buf.n - (char *)v12buf.buf)); 1052 break; 1053 } 1054 #undef FROM_NADDR 1055 } 1056 1057 1058 /* 1059 * Process a single input route. 1060 */ 1061 void 1062 input_route(in_addr_t dst, /* network order */ 1063 in_addr_t mask, 1064 struct rt_spare *new, 1065 struct netinfo *n, 1066 uint16_t rt_state) 1067 { 1068 int i; 1069 struct rt_entry *rt; 1070 struct rt_spare *rts, *rts0; 1071 struct interface *ifp1; 1072 struct rt_spare *ptr; 1073 size_t ptrsize; 1074 1075 /* 1076 * See if we can already get there by a working interface. Ignore 1077 * if so. 1078 */ 1079 ifp1 = ifwithaddr(dst, _B_TRUE, _B_FALSE); 1080 if (ifp1 != NULL && (ifp1->int_state & IS_PASSIVE)) 1081 return; 1082 1083 /* 1084 * Look for the route in our table. 1085 */ 1086 rt = rtget(dst, mask); 1087 1088 /* Consider adding the route if we do not already have it. */ 1089 if (rt == NULL) { 1090 /* Ignore unknown routes being poisoned. */ 1091 if (new->rts_metric == HOPCNT_INFINITY) 1092 return; 1093 1094 /* Ignore the route if it points to us */ 1095 if (n != NULL && n->n_nhop != 0 && 1096 NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) 1097 return; 1098 1099 /* 1100 * If something has not gone crazy and tried to fill 1101 * our memory, accept the new route. 1102 */ 1103 rtadd(dst, mask, rt_state, new); 1104 return; 1105 } 1106 1107 /* 1108 * We already know about the route. Consider this update. 1109 * 1110 * If (rt->rt_state & RS_NET_SYN), then this route 1111 * is the same as a network route we have inferred 1112 * for subnets we know, in order to tell RIPv1 routers 1113 * about the subnets. 1114 * 1115 * It is impossible to tell if the route is coming 1116 * from a distant RIPv2 router with the standard 1117 * netmask because that router knows about the entire 1118 * network, or if it is a round-about echo of a 1119 * synthetic, RIPv1 network route of our own. 1120 * The worst is that both kinds of routes might be 1121 * received, and the bad one might have the smaller 1122 * metric. Partly solve this problem by never 1123 * aggregating into such a route. Also keep it 1124 * around as long as the interface exists. 1125 */ 1126 1127 rts0 = rt->rt_spares; 1128 for (rts = rts0, i = rt->rt_num_spares; i != 0; i--, rts++) { 1129 if (rts->rts_router == new->rts_router) 1130 break; 1131 /* 1132 * Note the worst slot to reuse, 1133 * other than the current slot. 1134 */ 1135 if (BETTER_LINK(rt, rts0, rts)) 1136 rts0 = rts; 1137 } 1138 if (i != 0) { 1139 /* 1140 * Found a route from the router already in the table. 1141 */ 1142 1143 /* 1144 * If the new route is a route broken down from an 1145 * aggregated route, and if the previous route is either 1146 * not a broken down route or was broken down from a finer 1147 * netmask, and if the previous route is current, 1148 * then forget this one. 1149 */ 1150 if (new->rts_de_ag > rts->rts_de_ag && 1151 now_stale <= rts->rts_time) 1152 return; 1153 1154 /* 1155 * Keep poisoned routes around only long enough to pass 1156 * the poison on. Use a new timestamp for good routes. 1157 */ 1158 if (rts->rts_metric == HOPCNT_INFINITY && 1159 new->rts_metric == HOPCNT_INFINITY) 1160 new->rts_time = rts->rts_time; 1161 1162 /* 1163 * If this is an update for the router we currently prefer, 1164 * then note it. 1165 */ 1166 if (i == rt->rt_num_spares) { 1167 rtchange(rt, rt->rt_state | rt_state, new, 0); 1168 /* 1169 * If the route got worse, check for something better. 1170 */ 1171 if (new->rts_metric != rts->rts_metric) 1172 rtswitch(rt, 0); 1173 return; 1174 } 1175 1176 /* 1177 * This is an update for a spare route. 1178 * Finished if the route is unchanged. 1179 */ 1180 if (rts->rts_gate == new->rts_gate && 1181 rts->rts_metric == new->rts_metric && 1182 rts->rts_tag == new->rts_tag) { 1183 if ((rt->rt_dst == RIP_DEFAULT) && 1184 (rts->rts_ifp != new->rts_ifp)) 1185 trace_misc("input_route update for spare"); 1186 trace_upslot(rt, rts, new); 1187 *rts = *new; 1188 return; 1189 } 1190 1191 /* 1192 * Forget it if it has gone bad. 1193 */ 1194 if (new->rts_metric == HOPCNT_INFINITY) { 1195 rts_delete(rt, rts); 1196 return; 1197 } 1198 1199 } else { 1200 /* 1201 * The update is for a route we know about, 1202 * but not from a familiar router. 1203 * 1204 * Ignore the route if it points to us. 1205 */ 1206 if (n != NULL && n->n_nhop != 0 && 1207 NULL != ifwithaddr(n->n_nhop, _B_TRUE, _B_FALSE)) 1208 return; 1209 1210 /* the loop above set rts0=worst spare */ 1211 if (rts0->rts_metric < HOPCNT_INFINITY) { 1212 ptrsize = (rt->rt_num_spares + SPARE_INC) * 1213 sizeof (struct rt_spare); 1214 ptr = realloc(rt->rt_spares, ptrsize); 1215 if (ptr != NULL) { 1216 1217 rt->rt_spares = ptr; 1218 rts0 = &rt->rt_spares[rt->rt_num_spares]; 1219 (void) memset(rts0, 0, 1220 SPARE_INC * sizeof (struct rt_spare)); 1221 rt->rt_num_spares += SPARE_INC; 1222 for (rts = rts0, i = SPARE_INC; 1223 i != 0; i--, rts++) 1224 rts->rts_metric = HOPCNT_INFINITY; 1225 } 1226 } 1227 rts = rts0; 1228 1229 /* 1230 * Save the route as a spare only if it has 1231 * a better metric than our worst spare. 1232 * This also ignores poisoned routes (those 1233 * received with metric HOPCNT_INFINITY). 1234 */ 1235 if (new->rts_metric >= rts->rts_metric) 1236 return; 1237 } 1238 trace_upslot(rt, rts, new); 1239 *rts = *new; 1240 1241 /* try to switch to a better route */ 1242 rtswitch(rt, rts); 1243 } 1244 1245 /* 1246 * Recorded information about peer's MD5 sequence numbers. This is 1247 * used to validate that received sequence numbers are in 1248 * non-decreasing order as per the RFC. 1249 */ 1250 struct peer_hash { 1251 struct peer_hash *ph_next; 1252 in_addr_t ph_addr; 1253 time_t ph_heard; 1254 uint32_t ph_seqno; 1255 }; 1256 1257 static struct peer_hash **peer_hashes; 1258 static int ph_index; 1259 static int ph_num_peers; 1260 1261 /* 1262 * Get a peer_hash structure from the hash of known peers. Create a 1263 * new one if not found. Returns NULL on unrecoverable allocation 1264 * failure. 1265 */ 1266 static struct peer_hash * 1267 get_peer_info(in_addr_t from) 1268 { 1269 struct peer_hash *php; 1270 struct peer_hash *pnhp; 1271 struct peer_hash **ph_pp; 1272 struct peer_hash **ph2_pp; 1273 struct peer_hash **ph3_pp; 1274 int i; 1275 static uint_t failed_count; 1276 1277 if (peer_hashes == NULL) { 1278 peer_hashes = calloc(hash_table_sizes[0], 1279 sizeof (peer_hashes[0])); 1280 if (peer_hashes == NULL) { 1281 if (++failed_count % 100 == 1) 1282 msglog("no memory for peer hash"); 1283 return (NULL); 1284 } 1285 } 1286 /* Search for peer in existing hash table */ 1287 ph_pp = peer_hashes + (from % hash_table_sizes[ph_index]); 1288 for (php = ph_pp[0]; php != NULL; php = php->ph_next) { 1289 if (php->ph_addr == from) 1290 return (php); 1291 } 1292 /* 1293 * Not found; we need to add this peer to the table. If there 1294 * are already too many peers, then try to expand the table 1295 * first. It's not a big deal if we can't expand the table 1296 * right now due to memory constraints. We'll try again 1297 * later. 1298 */ 1299 if (ph_num_peers >= hash_table_sizes[ph_index] * 5 && 1300 hash_table_sizes[ph_index + 1] != 0 && 1301 (ph_pp = calloc(hash_table_sizes[ph_index + 1], 1302 sizeof (peer_hashes[0]))) != NULL) { 1303 ph2_pp = peer_hashes; 1304 for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { 1305 for (php = ph2_pp[i]; php != NULL; php = pnhp) { 1306 pnhp = php->ph_next; 1307 ph3_pp = ph_pp + (php->ph_addr % 1308 hash_table_sizes[ph_index + 1]); 1309 php->ph_next = ph3_pp[0]; 1310 ph3_pp[0] = php; 1311 } 1312 } 1313 ph_index++; 1314 free(peer_hashes); 1315 peer_hashes = ph_pp; 1316 ph_pp += from % hash_table_sizes[ph_index]; 1317 } 1318 php = calloc(sizeof (*php), 1); 1319 if (php == NULL) { 1320 if (++failed_count % 100 == 1) 1321 msglog("no memory for peer hash entry"); 1322 } else { 1323 php->ph_addr = from; 1324 php->ph_heard = now.tv_sec; 1325 php->ph_next = ph_pp[0]; 1326 ph_pp[0] = php; 1327 ph_num_peers++; 1328 } 1329 return (php); 1330 } 1331 1332 /* 1333 * Age out entries in the peer table. This is called every time we do 1334 * a normal 30 second broadcast. 1335 */ 1336 void 1337 age_peer_info(void) 1338 { 1339 struct peer_hash *php; 1340 struct peer_hash *next_ph; 1341 struct peer_hash *prev_ph; 1342 struct peer_hash **ph_pp; 1343 int i; 1344 1345 /* 1346 * Scan through the list and remove peers that should not 1347 * still have valid authenticated entries in the routing 1348 * table. 1349 */ 1350 if ((ph_pp = peer_hashes) == NULL || ph_num_peers == 0) 1351 return; 1352 for (i = hash_table_sizes[ph_index] - 1; i >= 0; i--) { 1353 prev_ph = NULL; 1354 for (php = ph_pp[i]; php != NULL; php = next_ph) { 1355 next_ph = php->ph_next; 1356 if (php->ph_heard <= now_expire) { 1357 if (prev_ph == NULL) 1358 ph_pp[i] = next_ph; 1359 else 1360 prev_ph->ph_next = next_ph; 1361 free(php); 1362 if (--ph_num_peers == 0) 1363 return; 1364 } else { 1365 prev_ph = php; 1366 } 1367 } 1368 } 1369 } 1370 1371 static boolean_t /* _B_FALSE if bad, _B_TRUE if good */ 1372 ck_passwd(struct interface *aifp, 1373 struct rip *rip, 1374 uint8_t *lim, 1375 in_addr_t from, 1376 struct msg_limit *use_authp) 1377 { 1378 #define NA (rip->rip_auths) 1379 struct netauth *na2; 1380 struct auth *ap; 1381 MD5_CTX md5_ctx; 1382 uchar_t hash[RIP_AUTH_PW_LEN]; 1383 int i, len; 1384 struct peer_hash *php; 1385 uint32_t seqno; 1386 1387 if ((uint8_t *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 1388 msglim(use_authp, from, "missing auth data from %s", 1389 naddr_ntoa(from)); 1390 return (_B_FALSE); 1391 } 1392 1393 /* 1394 * Validate sequence number on RIPv2 responses using keyed MD5 1395 * authentication per RFC 2082 section 3.2.2. Note that if we 1396 * can't locate the peer information (due to transient 1397 * allocation problems), then we don't do the test. Also note 1398 * that we assume that all sequence numbers 0x80000000 or more 1399 * away are "less than." 1400 * 1401 * We intentionally violate RFC 2082 with respect to one case: 1402 * restablishing contact. The RFC says that you should 1403 * continue to ignore old sequence numbers in this case but 1404 * make a special allowance for 0. This is extremely foolish. 1405 * The problem is that if the router has crashed, it's 1406 * entirely possible that either we'll miss sequence zero (or 1407 * that it might not even send it!) or that the peer doesn't 1408 * remember what it last used for a sequence number. In 1409 * either case, we'll create a failure state that persists 1410 * until the sequence number happens to advance past the last 1411 * one we saw. This is bad because it means that we may have 1412 * to wait until the router has been up for at least as long 1413 * as it was last time before we even pay attention to it. 1414 * Meanwhile, other routers may listen to it if they hadn't 1415 * seen it before (i.e., if they crashed in the meantime). 1416 * This means -- perversely -- that stable systems that stay 1417 * "up" for a long time pay a penalty for doing so. 1418 */ 1419 if (rip->rip_cmd == RIPCMD_RESPONSE && NA->a_type == RIP_AUTH_MD5 && 1420 (php = get_peer_info(from)) != NULL) { 1421 /* 1422 * If the entry that we find has been updated 1423 * recently enough that the routes are known 1424 * to still be good, but the sequence number 1425 * looks bad, then discard the packet. 1426 */ 1427 seqno = ntohl(NA->au.a_md5.md5_seqno); 1428 if (php->ph_heard > now_expire && php->ph_seqno != 0 && 1429 (seqno == 0 || ((seqno - php->ph_seqno) & 0x80000000ul))) { 1430 msglim(use_authp, from, 1431 "discarding sequence %x (older than %x)", 1432 (unsigned)seqno, (unsigned)php->ph_seqno); 1433 return (_B_FALSE); 1434 } 1435 php->ph_heard = now.tv_sec; 1436 php->ph_seqno = seqno; 1437 } 1438 1439 /* 1440 * accept any current (+/- 24 hours) password 1441 */ 1442 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 1443 if (ap->type != NA->a_type || 1444 (ulong_t)ap->start > (ulong_t)clk.tv_sec+DAY || 1445 (ulong_t)ap->end+DAY < (ulong_t)clk.tv_sec) 1446 continue; 1447 1448 if (NA->a_type == RIP_AUTH_PW) { 1449 if (0 == memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 1450 return (_B_TRUE); 1451 1452 } else { 1453 /* 1454 * accept MD5 secret with the right key ID 1455 */ 1456 if (NA->au.a_md5.md5_keyid != ap->keyid) 1457 continue; 1458 1459 len = ntohs(NA->au.a_md5.md5_pkt_len); 1460 if ((len - sizeof (*rip)) % sizeof (*NA) != 0 || 1461 len > (lim - (uint8_t *)rip - sizeof (*NA))) { 1462 msglim(use_authp, from, 1463 "wrong MD5 RIPv2 packet length of %d" 1464 " instead of %d from %s", 1465 len, lim - (uint8_t *)rip - sizeof (*NA), 1466 naddr_ntoa(from)); 1467 return (_B_FALSE); 1468 } 1469 na2 = (struct netauth *)(rip->rip_nets + 1470 (len - 4) / sizeof (struct netinfo)); 1471 1472 /* 1473 * Given a good hash value, these are not security 1474 * problems so be generous and accept the routes, 1475 * after complaining. 1476 */ 1477 if (TRACEPACKETS) { 1478 if (NA->au.a_md5.md5_auth_len != 1479 RIP_AUTH_MD5_LEN) 1480 msglim(use_authp, from, 1481 "unknown MD5 RIPv2 auth len %#x" 1482 " instead of %#x from %s", 1483 NA->au.a_md5.md5_auth_len, 1484 RIP_AUTH_MD5_LEN, 1485 naddr_ntoa(from)); 1486 if (na2->a_family != RIP_AF_AUTH) 1487 msglim(use_authp, from, 1488 "unknown MD5 RIPv2 family %#x" 1489 " instead of %#x from %s", 1490 na2->a_family, RIP_AF_AUTH, 1491 naddr_ntoa(from)); 1492 if (na2->a_type != RIP_AUTH_TRAILER) 1493 msglim(use_authp, from, 1494 "MD5 RIPv2 hash has %#x" 1495 " instead of %#x from %s", 1496 ntohs(na2->a_type), 1497 ntohs(RIP_AUTH_TRAILER), 1498 naddr_ntoa(from)); 1499 } 1500 1501 MD5Init(&md5_ctx); 1502 /* 1503 * len+4 to include auth trailer's family/type in 1504 * MD5 sum 1505 */ 1506 MD5Update(&md5_ctx, (uchar_t *)rip, len + 4); 1507 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); 1508 MD5Final(hash, &md5_ctx); 1509 if (0 == memcmp(hash, na2->au.au_pw, sizeof (hash))) 1510 return (_B_TRUE); 1511 } 1512 } 1513 1514 msglim(use_authp, from, "bad auth data from %s", 1515 naddr_ntoa(from)); 1516 return (_B_FALSE); 1517 #undef NA 1518 } 1519