1 /* $KAME: rtsol.c,v 1.27 2003/10/05 00:09:36 itojun Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * Copyright (C) 2011 Hiroki Sato
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the project nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $FreeBSD$
35 */
36
37 #include <sys/param.h>
38 #include <sys/socket.h>
39 #include <sys/uio.h>
40 #include <sys/queue.h>
41 #include <sys/wait.h>
42 #include <sys/stat.h>
43
44 #include <net/if.h>
45 #include <net/route.h>
46 #include <net/if_dl.h>
47
48 #define __BSD_VISIBLE 1 /* IN6ADDR_LINKLOCAL_ALLROUTERS_INIT */
49 #include <netinet/in.h>
50 #undef __BSD_VISIBLE
51 #include <netinet/ip6.h>
52 #include <netinet6/ip6_var.h>
53 #include <netinet/icmp6.h>
54
55 #include <arpa/inet.h>
56
57 #include <netdb.h>
58 #include <time.h>
59 #include <fcntl.h>
60 #include <unistd.h>
61 #include <stdio.h>
62 #include <time.h>
63 #include <err.h>
64 #include <errno.h>
65 #include <string.h>
66 #include <stdlib.h>
67 #include <syslog.h>
68 #include "rtsold.h"
69
70 static struct msghdr rcvmhdr;
71 static struct msghdr sndmhdr;
72 static struct iovec rcviov[2];
73 static struct iovec sndiov[2];
74 static struct sockaddr_in6 from;
75 static int rcvcmsglen;
76
77 int rssock;
78 static char rsid[IFNAMSIZ + 1 + sizeof(DNSINFO_ORIGIN_LABEL) + 1 + NI_MAXHOST];
79 struct ifinfo_head_t ifinfo_head =
80 TAILQ_HEAD_INITIALIZER(ifinfo_head);
81
82 static const struct sockaddr_in6 sin6_allrouters = {
83 .sin6_len = sizeof(sin6_allrouters),
84 .sin6_family = AF_INET6,
85 .sin6_addr = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
86 };
87
88 static void call_script(const int, const char *const *,
89 struct script_msg_head_t *);
90 static size_t dname_labeldec(char *, size_t, const char *);
91 static int safefile(const char *);
92 static struct ra_opt *find_raopt(struct rainfo *, int, void *, size_t);
93 static int ra_opt_rdnss_dispatch(struct ifinfo *, struct rainfo *,
94 struct script_msg_head_t *, struct script_msg_head_t *);
95 static char *make_rsid(const char *, const char *, struct rainfo *);
96
97 #define _ARGS_OTHER otherconf_script, ifi->ifname
98 #define _ARGS_RESADD resolvconf_script, "-a", rsid
99 #define _ARGS_RESDEL resolvconf_script, "-d", rsid
100
101 #define CALL_SCRIPT(name, sm_head) do { \
102 const char *const sarg[] = { _ARGS_##name, NULL }; \
103 call_script(sizeof(sarg), sarg, sm_head); \
104 } while (0)
105
106 #define ELM_MALLOC(p, error_action) do { \
107 p = malloc(sizeof(*p)); \
108 if (p == NULL) { \
109 warnmsg(LOG_ERR, __func__, "malloc failed: %s", \
110 strerror(errno)); \
111 error_action; \
112 } \
113 memset(p, 0, sizeof(*p)); \
114 } while (0)
115
116 int
sockopen(void)117 sockopen(void)
118 {
119 static u_char *rcvcmsgbuf = NULL, *sndcmsgbuf = NULL;
120 int sndcmsglen, on;
121 static u_char answer[1500];
122 struct icmp6_filter filt;
123
124 sndcmsglen = rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
125 CMSG_SPACE(sizeof(int));
126 if (rcvcmsgbuf == NULL && (rcvcmsgbuf = malloc(rcvcmsglen)) == NULL) {
127 warnmsg(LOG_ERR, __func__,
128 "malloc for receive msghdr failed");
129 return (-1);
130 }
131 if (sndcmsgbuf == NULL && (sndcmsgbuf = malloc(sndcmsglen)) == NULL) {
132 warnmsg(LOG_ERR, __func__,
133 "malloc for send msghdr failed");
134 return (-1);
135 }
136 if ((rssock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
137 warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
138 return (-1);
139 }
140
141 /* specify to tell receiving interface */
142 on = 1;
143 if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
144 sizeof(on)) < 0) {
145 warnmsg(LOG_ERR, __func__, "IPV6_RECVPKTINFO: %s",
146 strerror(errno));
147 exit(1);
148 }
149
150 /* specify to tell value of hoplimit field of received IP6 hdr */
151 on = 1;
152 if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
153 sizeof(on)) < 0) {
154 warnmsg(LOG_ERR, __func__, "IPV6_RECVHOPLIMIT: %s",
155 strerror(errno));
156 exit(1);
157 }
158
159 /* specfiy to accept only router advertisements on the socket */
160 ICMP6_FILTER_SETBLOCKALL(&filt);
161 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
162 if (setsockopt(rssock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
163 sizeof(filt)) == -1) {
164 warnmsg(LOG_ERR, __func__, "setsockopt(ICMP6_FILTER): %s",
165 strerror(errno));
166 return(-1);
167 }
168
169 /* initialize msghdr for receiving packets */
170 rcviov[0].iov_base = (caddr_t)answer;
171 rcviov[0].iov_len = sizeof(answer);
172 rcvmhdr.msg_name = (caddr_t)&from;
173 rcvmhdr.msg_iov = rcviov;
174 rcvmhdr.msg_iovlen = 1;
175 rcvmhdr.msg_control = (caddr_t) rcvcmsgbuf;
176
177 /* initialize msghdr for sending packets */
178 sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
179 sndmhdr.msg_iov = sndiov;
180 sndmhdr.msg_iovlen = 1;
181 sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
182 sndmhdr.msg_controllen = sndcmsglen;
183
184 return (rssock);
185 }
186
187 void
sendpacket(struct ifinfo * ifi)188 sendpacket(struct ifinfo *ifi)
189 {
190 struct in6_pktinfo *pi;
191 struct cmsghdr *cm;
192 int hoplimit = 255;
193 ssize_t i;
194 struct sockaddr_in6 dst;
195
196 dst = sin6_allrouters;
197 dst.sin6_scope_id = ifi->linkid;
198
199 sndmhdr.msg_name = (caddr_t)&dst;
200 sndmhdr.msg_iov[0].iov_base = (caddr_t)ifi->rs_data;
201 sndmhdr.msg_iov[0].iov_len = ifi->rs_datalen;
202
203 cm = CMSG_FIRSTHDR(&sndmhdr);
204 /* specify the outgoing interface */
205 cm->cmsg_level = IPPROTO_IPV6;
206 cm->cmsg_type = IPV6_PKTINFO;
207 cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
208 pi = (struct in6_pktinfo *)(void *)CMSG_DATA(cm);
209 memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr)); /*XXX*/
210 pi->ipi6_ifindex = ifi->sdl->sdl_index;
211
212 /* specify the hop limit of the packet */
213 cm = CMSG_NXTHDR(&sndmhdr, cm);
214 cm->cmsg_level = IPPROTO_IPV6;
215 cm->cmsg_type = IPV6_HOPLIMIT;
216 cm->cmsg_len = CMSG_LEN(sizeof(int));
217 memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
218
219 warnmsg(LOG_DEBUG, __func__,
220 "send RS on %s, whose state is %d",
221 ifi->ifname, ifi->state);
222 i = sendmsg(rssock, &sndmhdr, 0);
223 if (i < 0 || (size_t)i != ifi->rs_datalen) {
224 /*
225 * ENETDOWN is not so serious, especially when using several
226 * network cards on a mobile node. We ignore it.
227 */
228 if (errno != ENETDOWN || dflag > 0)
229 warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
230 ifi->ifname, strerror(errno));
231 }
232
233 /* update counter */
234 ifi->probes++;
235 }
236
237 void
rtsol_input(int s)238 rtsol_input(int s)
239 {
240 char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
241 int l, ifindex = 0, *hlimp = NULL;
242 ssize_t msglen;
243 struct in6_pktinfo *pi = NULL;
244 struct ifinfo *ifi = NULL;
245 struct ra_opt *rao = NULL;
246 struct icmp6_hdr *icp;
247 struct nd_router_advert *nd_ra;
248 struct cmsghdr *cm;
249 struct rainfo *rai;
250 char *raoptp;
251 char *p;
252 struct in6_addr *addr;
253 struct nd_opt_hdr *ndo;
254 struct nd_opt_rdnss *rdnss;
255 struct nd_opt_dnssl *dnssl;
256 size_t len;
257 char nsbuf[INET6_ADDRSTRLEN + 1 + IFNAMSIZ + 1];
258 char dname[NI_MAXHOST];
259 struct timespec now;
260 struct timespec lifetime;
261 int newent_rai;
262 int newent_rao;
263
264 /* get message. namelen and controllen must always be initialized. */
265 rcvmhdr.msg_namelen = sizeof(from);
266 rcvmhdr.msg_controllen = rcvcmsglen;
267 if ((msglen = recvmsg(s, &rcvmhdr, 0)) < 0) {
268 warnmsg(LOG_ERR, __func__, "recvmsg: %s", strerror(errno));
269 return;
270 }
271
272 /* extract optional information via Advanced API */
273 for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&rcvmhdr); cm;
274 cm = (struct cmsghdr *)CMSG_NXTHDR(&rcvmhdr, cm)) {
275 if (cm->cmsg_level == IPPROTO_IPV6 &&
276 cm->cmsg_type == IPV6_PKTINFO &&
277 cm->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) {
278 pi = (struct in6_pktinfo *)(void *)(CMSG_DATA(cm));
279 ifindex = pi->ipi6_ifindex;
280 }
281 if (cm->cmsg_level == IPPROTO_IPV6 &&
282 cm->cmsg_type == IPV6_HOPLIMIT &&
283 cm->cmsg_len == CMSG_LEN(sizeof(int)))
284 hlimp = (int *)(void *)CMSG_DATA(cm);
285 }
286
287 if (ifindex == 0) {
288 warnmsg(LOG_ERR, __func__,
289 "failed to get receiving interface");
290 return;
291 }
292 if (hlimp == NULL) {
293 warnmsg(LOG_ERR, __func__,
294 "failed to get receiving hop limit");
295 return;
296 }
297
298 if ((size_t)msglen < sizeof(struct nd_router_advert)) {
299 warnmsg(LOG_INFO, __func__,
300 "packet size(%zd) is too short", msglen);
301 return;
302 }
303
304 icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;
305
306 if (icp->icmp6_type != ND_ROUTER_ADVERT) {
307 /*
308 * this should not happen because we configured a filter
309 * that only passes RAs on the receiving socket.
310 */
311 warnmsg(LOG_ERR, __func__,
312 "invalid icmp type(%d) from %s on %s", icp->icmp6_type,
313 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
314 sizeof(ntopbuf)),
315 if_indextoname(pi->ipi6_ifindex, ifnamebuf));
316 return;
317 }
318
319 if (icp->icmp6_code != 0) {
320 warnmsg(LOG_INFO, __func__,
321 "invalid icmp code(%d) from %s on %s", icp->icmp6_code,
322 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
323 sizeof(ntopbuf)),
324 if_indextoname(pi->ipi6_ifindex, ifnamebuf));
325 return;
326 }
327
328 if (*hlimp != 255) {
329 warnmsg(LOG_INFO, __func__,
330 "invalid RA with hop limit(%d) from %s on %s",
331 *hlimp,
332 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
333 sizeof(ntopbuf)),
334 if_indextoname(pi->ipi6_ifindex, ifnamebuf));
335 return;
336 }
337
338 if (pi && !IN6_IS_ADDR_LINKLOCAL(&from.sin6_addr)) {
339 warnmsg(LOG_INFO, __func__,
340 "invalid RA with non link-local source from %s on %s",
341 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
342 sizeof(ntopbuf)),
343 if_indextoname(pi->ipi6_ifindex, ifnamebuf));
344 return;
345 }
346
347 /* xxx: more validation? */
348
349 if ((ifi = find_ifinfo(pi->ipi6_ifindex)) == NULL) {
350 warnmsg(LOG_DEBUG, __func__,
351 "received RA from %s on an unexpected IF(%s)",
352 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
353 sizeof(ntopbuf)),
354 if_indextoname(pi->ipi6_ifindex, ifnamebuf));
355 return;
356 }
357
358 warnmsg(LOG_DEBUG, __func__,
359 "received RA from %s on %s, state is %d",
360 inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf, sizeof(ntopbuf)),
361 ifi->ifname, ifi->state);
362
363 nd_ra = (struct nd_router_advert *)icp;
364
365 /*
366 * Process the "O bit."
367 * If the value of OtherConfigFlag changes from FALSE to TRUE, the
368 * host should invoke the stateful autoconfiguration protocol,
369 * requesting information.
370 * [RFC 2462 Section 5.5.3]
371 */
372 if (((nd_ra->nd_ra_flags_reserved) & ND_RA_FLAG_OTHER) &&
373 !ifi->otherconfig) {
374 warnmsg(LOG_DEBUG, __func__,
375 "OtherConfigFlag on %s is turned on", ifi->ifname);
376 ifi->otherconfig = 1;
377 CALL_SCRIPT(OTHER, NULL);
378 }
379 clock_gettime(CLOCK_MONOTONIC_FAST, &now);
380 newent_rai = 0;
381 rai = find_rainfo(ifi, &from);
382 if (rai == NULL) {
383 ELM_MALLOC(rai, exit(1));
384 rai->rai_ifinfo = ifi;
385 TAILQ_INIT(&rai->rai_ra_opt);
386 rai->rai_saddr.sin6_family = AF_INET6;
387 rai->rai_saddr.sin6_len = sizeof(rai->rai_saddr);
388 memcpy(&rai->rai_saddr.sin6_addr, &from.sin6_addr,
389 sizeof(rai->rai_saddr.sin6_addr));
390 newent_rai = 1;
391 }
392
393 #define RA_OPT_NEXT_HDR(x) (struct nd_opt_hdr *)((char *)(x) + \
394 (((struct nd_opt_hdr *)(x))->nd_opt_len * 8))
395 /* Process RA options. */
396 warnmsg(LOG_DEBUG, __func__, "Processing RA");
397 raoptp = (char *)icp + sizeof(struct nd_router_advert);
398 while (raoptp < (char *)icp + msglen) {
399 ndo = (struct nd_opt_hdr *)raoptp;
400 warnmsg(LOG_DEBUG, __func__, "ndo = %p", raoptp);
401 warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_type = %d",
402 ndo->nd_opt_type);
403 warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_len = %d",
404 ndo->nd_opt_len);
405
406 if (ndo->nd_opt_len == 0) {
407 warnmsg(LOG_INFO, __func__, "invalid option length 0.");
408 break;
409 }
410 if ((char *)RA_OPT_NEXT_HDR(raoptp) > (char *)icp + msglen) {
411 warnmsg(LOG_INFO, __func__, "option length overflow.");
412 break;
413 }
414
415 switch (ndo->nd_opt_type) {
416 case ND_OPT_RDNSS:
417 rdnss = (struct nd_opt_rdnss *)raoptp;
418
419 /* Optlen sanity check (Section 5.3.1 in RFC 6106) */
420 if (rdnss->nd_opt_rdnss_len < 3) {
421 warnmsg(LOG_INFO, __func__,
422 "too short RDNSS option"
423 "in RA from %s was ignored.",
424 inet_ntop(AF_INET6, &from.sin6_addr,
425 ntopbuf, sizeof(ntopbuf)));
426 break;
427 }
428
429 addr = (struct in6_addr *)(void *)(raoptp + sizeof(*rdnss));
430 while ((char *)addr < (char *)RA_OPT_NEXT_HDR(raoptp)) {
431 if (inet_ntop(AF_INET6, addr, ntopbuf,
432 sizeof(ntopbuf)) == NULL) {
433 warnmsg(LOG_INFO, __func__,
434 "an invalid address in RDNSS option"
435 " in RA from %s was ignored.",
436 inet_ntop(AF_INET6, &from.sin6_addr,
437 ntopbuf, sizeof(ntopbuf)));
438 addr++;
439 continue;
440 }
441 if (IN6_IS_ADDR_LINKLOCAL(addr))
442 /* XXX: % has to be escaped here */
443 l = snprintf(nsbuf, sizeof(nsbuf),
444 "%s%c%s", ntopbuf,
445 SCOPE_DELIMITER,
446 ifi->ifname);
447 else
448 l = snprintf(nsbuf, sizeof(nsbuf),
449 "%s", ntopbuf);
450 if (l < 0 || (size_t)l >= sizeof(nsbuf)) {
451 warnmsg(LOG_ERR, __func__,
452 "address copying error in "
453 "RDNSS option: %d.", l);
454 addr++;
455 continue;
456 }
457 warnmsg(LOG_DEBUG, __func__, "nsbuf = %s",
458 nsbuf);
459
460 newent_rao = 0;
461 rao = find_raopt(rai, ndo->nd_opt_type, nsbuf,
462 strlen(nsbuf));
463 if (rao == NULL) {
464 ELM_MALLOC(rao, break);
465 rao->rao_type = ndo->nd_opt_type;
466 rao->rao_len = strlen(nsbuf);
467 rao->rao_msg = strdup(nsbuf);
468 if (rao->rao_msg == NULL) {
469 warnmsg(LOG_ERR, __func__,
470 "strdup failed: %s",
471 strerror(errno));
472 free(rao);
473 addr++;
474 continue;
475 }
476 newent_rao = 1;
477 }
478 /* Set expiration timer */
479 memset(&rao->rao_expire, 0,
480 sizeof(rao->rao_expire));
481 memset(&lifetime, 0, sizeof(lifetime));
482 lifetime.tv_sec =
483 ntohl(rdnss->nd_opt_rdnss_lifetime);
484 TS_ADD(&now, &lifetime, &rao->rao_expire);
485
486 if (newent_rao)
487 TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
488 rao, rao_next);
489 addr++;
490 }
491 break;
492 case ND_OPT_DNSSL:
493 dnssl = (struct nd_opt_dnssl *)raoptp;
494
495 /* Optlen sanity check (Section 5.3.1 in RFC 6106) */
496 if (dnssl->nd_opt_dnssl_len < 2) {
497 warnmsg(LOG_INFO, __func__,
498 "too short DNSSL option"
499 "in RA from %s was ignored.",
500 inet_ntop(AF_INET6, &from.sin6_addr,
501 ntopbuf, sizeof(ntopbuf)));
502 break;
503 }
504
505 /*
506 * Ensure NUL-termination in DNSSL in case of
507 * malformed field.
508 */
509 p = (char *)RA_OPT_NEXT_HDR(raoptp);
510 *(p - 1) = '\0';
511
512 p = raoptp + sizeof(*dnssl);
513 while (1 < (len = dname_labeldec(dname, sizeof(dname),
514 p))) {
515 /* length == 1 means empty string */
516 warnmsg(LOG_DEBUG, __func__, "dname = %s",
517 dname);
518
519 newent_rao = 0;
520 rao = find_raopt(rai, ndo->nd_opt_type, dname,
521 strlen(dname));
522 if (rao == NULL) {
523 ELM_MALLOC(rao, break);
524 rao->rao_type = ndo->nd_opt_type;
525 rao->rao_len = strlen(dname);
526 rao->rao_msg = strdup(dname);
527 if (rao->rao_msg == NULL) {
528 warnmsg(LOG_ERR, __func__,
529 "strdup failed: %s",
530 strerror(errno));
531 free(rao);
532 addr++;
533 continue;
534 }
535 newent_rao = 1;
536 }
537 /* Set expiration timer */
538 memset(&rao->rao_expire, 0,
539 sizeof(rao->rao_expire));
540 memset(&lifetime, 0, sizeof(lifetime));
541 lifetime.tv_sec =
542 ntohl(dnssl->nd_opt_dnssl_lifetime);
543 TS_ADD(&now, &lifetime, &rao->rao_expire);
544
545 if (newent_rao)
546 TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
547 rao, rao_next);
548 p += len;
549 }
550 break;
551 default:
552 /* nothing to do for other options */
553 break;
554 }
555 raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
556 }
557 if (newent_rai)
558 TAILQ_INSERT_TAIL(&ifi->ifi_rainfo, rai, rai_next);
559
560 ra_opt_handler(ifi);
561 ifi->racnt++;
562
563 switch (ifi->state) {
564 case IFS_IDLE: /* should be ignored */
565 case IFS_DELAY: /* right? */
566 break;
567 case IFS_PROBE:
568 ifi->state = IFS_IDLE;
569 ifi->probes = 0;
570 rtsol_timer_update(ifi);
571 break;
572 }
573 }
574
575 static char resstr_ns_prefix[] = "nameserver ";
576 static char resstr_sh_prefix[] = "search ";
577 static char resstr_nl[] = "\n";
578 static char resstr_sp[] = " ";
579
580 int
ra_opt_handler(struct ifinfo * ifi)581 ra_opt_handler(struct ifinfo *ifi)
582 {
583 struct ra_opt *rao;
584 struct rainfo *rai;
585 struct script_msg *smp1, *smp2, *smp3;
586 struct timespec now;
587 struct script_msg_head_t sm_rdnss_head =
588 TAILQ_HEAD_INITIALIZER(sm_rdnss_head);
589 struct script_msg_head_t sm_dnssl_head =
590 TAILQ_HEAD_INITIALIZER(sm_dnssl_head);
591
592 int dcount, dlen;
593
594 dcount = 0;
595 dlen = strlen(resstr_sh_prefix) + strlen(resstr_nl);
596 clock_gettime(CLOCK_MONOTONIC_FAST, &now);
597
598 /*
599 * All options from multiple RAs with the same or different
600 * source addresses on a single interface will be gathered and
601 * handled, not overridden. [RFC 4861 6.3.4]
602 */
603 TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next) {
604 TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
605 switch (rao->rao_type) {
606 case ND_OPT_RDNSS:
607 if (TS_CMP(&now, &rao->rao_expire, >)) {
608 warnmsg(LOG_INFO, __func__,
609 "expired rdnss entry: %s",
610 (char *)rao->rao_msg);
611 break;
612 }
613 ELM_MALLOC(smp1, continue);
614 ELM_MALLOC(smp2, goto free1);
615 ELM_MALLOC(smp3, goto free2);
616 smp1->sm_msg = resstr_ns_prefix;
617 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp1,
618 sm_next);
619 smp2->sm_msg = rao->rao_msg;
620 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp2,
621 sm_next);
622 smp3->sm_msg = resstr_nl;
623 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp3,
624 sm_next);
625 ifi->ifi_rdnss = IFI_DNSOPT_STATE_RECEIVED;
626 break;
627 case ND_OPT_DNSSL:
628 if (TS_CMP(&now, &rao->rao_expire, >)) {
629 warnmsg(LOG_INFO, __func__,
630 "expired dnssl entry: %s",
631 (char *)rao->rao_msg);
632 break;
633 }
634 dcount++;
635 /* Check resolv.conf(5) restrictions. */
636 if (dcount > 6) {
637 warnmsg(LOG_INFO, __func__,
638 "dnssl entry exceeding maximum count (%d>6)"
639 ": %s", dcount, (char *)rao->rao_msg);
640 break;
641 }
642 if (256 < dlen + strlen(rao->rao_msg) +
643 strlen(resstr_sp)) {
644 warnmsg(LOG_INFO, __func__,
645 "dnssl entry exceeding maximum length "
646 "(>256): %s", (char *)rao->rao_msg);
647 break;
648 }
649 ELM_MALLOC(smp1, continue);
650 ELM_MALLOC(smp2, goto free1);
651 if (TAILQ_EMPTY(&sm_dnssl_head)) {
652 ELM_MALLOC(smp3, goto free2);
653 smp3->sm_msg = resstr_sh_prefix;
654 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp3,
655 sm_next);
656 }
657 smp1->sm_msg = rao->rao_msg;
658 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1,
659 sm_next);
660 smp2->sm_msg = resstr_sp;
661 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp2,
662 sm_next);
663 dlen += strlen(rao->rao_msg) +
664 strlen(resstr_sp);
665 ifi->ifi_dnssl = IFI_DNSOPT_STATE_RECEIVED;
666 break;
667 }
668 continue;
669 free2:
670 free(smp2);
671 free1:
672 free(smp1);
673 }
674 /* Call the script for each information source. */
675 if (uflag)
676 ra_opt_rdnss_dispatch(ifi, rai, &sm_rdnss_head,
677 &sm_dnssl_head);
678 }
679 /* Call the script for each interface. */
680 if (!uflag)
681 ra_opt_rdnss_dispatch(ifi, NULL, &sm_rdnss_head,
682 &sm_dnssl_head);
683 return (0);
684 }
685
686 char *
make_rsid(const char * ifname,const char * origin,struct rainfo * rai)687 make_rsid(const char *ifname, const char *origin, struct rainfo *rai)
688 {
689 char hbuf[NI_MAXHOST];
690
691 if (rai == NULL)
692 sprintf(rsid, "%s:%s", ifname, origin);
693 else {
694 if (!IN6_IS_ADDR_LINKLOCAL(&rai->rai_saddr.sin6_addr))
695 return (NULL);
696 if (getnameinfo((struct sockaddr *)&rai->rai_saddr,
697 rai->rai_saddr.sin6_len, hbuf, sizeof(hbuf), NULL, 0,
698 NI_NUMERICHOST) != 0)
699 return (NULL);
700 sprintf(rsid, "%s:%s:[%s]", ifname, origin, hbuf);
701 }
702 warnmsg(LOG_DEBUG, __func__, "rsid = [%s]", rsid);
703 return (rsid);
704 }
705
706 int
ra_opt_rdnss_dispatch(struct ifinfo * ifi,struct rainfo * rai,struct script_msg_head_t * sm_rdnss_head,struct script_msg_head_t * sm_dnssl_head)707 ra_opt_rdnss_dispatch(struct ifinfo *ifi, struct rainfo *rai,
708 struct script_msg_head_t *sm_rdnss_head,
709 struct script_msg_head_t *sm_dnssl_head)
710 {
711 struct script_msg *smp1;
712 const char *r;
713 int error;
714
715 error = 0;
716 /* Add \n for DNSSL list. */
717 if (!TAILQ_EMPTY(sm_dnssl_head)) {
718 ELM_MALLOC(smp1, goto ra_opt_rdnss_freeit);
719 smp1->sm_msg = resstr_nl;
720 TAILQ_INSERT_TAIL(sm_dnssl_head, smp1, sm_next);
721 }
722 TAILQ_CONCAT(sm_rdnss_head, sm_dnssl_head, sm_next);
723
724 r = make_rsid(ifi->ifname, DNSINFO_ORIGIN_LABEL, uflag ? rai : NULL);
725 if (r == NULL) {
726 warnmsg(LOG_ERR, __func__, "make_rsid() failed. "
727 "Script was not invoked.");
728 error = 1;
729 goto ra_opt_rdnss_freeit;
730 }
731 if (!TAILQ_EMPTY(sm_rdnss_head))
732 CALL_SCRIPT(RESADD, sm_rdnss_head);
733 else if (ifi->ifi_rdnss == IFI_DNSOPT_STATE_RECEIVED ||
734 ifi->ifi_dnssl == IFI_DNSOPT_STATE_RECEIVED) {
735 CALL_SCRIPT(RESDEL, NULL);
736 ifi->ifi_rdnss = IFI_DNSOPT_STATE_NOINFO;
737 ifi->ifi_dnssl = IFI_DNSOPT_STATE_NOINFO;
738 }
739
740 ra_opt_rdnss_freeit:
741 /* Clear script message queue. */
742 if (!TAILQ_EMPTY(sm_rdnss_head)) {
743 while ((smp1 = TAILQ_FIRST(sm_rdnss_head)) != NULL) {
744 TAILQ_REMOVE(sm_rdnss_head, smp1, sm_next);
745 free(smp1);
746 }
747 }
748 if (!TAILQ_EMPTY(sm_dnssl_head)) {
749 while ((smp1 = TAILQ_FIRST(sm_dnssl_head)) != NULL) {
750 TAILQ_REMOVE(sm_dnssl_head, smp1, sm_next);
751 free(smp1);
752 }
753 }
754 return (error);
755 }
756
757 static struct ra_opt *
find_raopt(struct rainfo * rai,int type,void * msg,size_t len)758 find_raopt(struct rainfo *rai, int type, void *msg, size_t len)
759 {
760 struct ra_opt *rao;
761
762 TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
763 if (rao->rao_type == type &&
764 rao->rao_len == strlen(msg) &&
765 memcmp(rao->rao_msg, msg, len) == 0)
766 break;
767 }
768
769 return (rao);
770 }
771
772 static void
call_script(const int argc,const char * const argv[],struct script_msg_head_t * sm_head)773 call_script(const int argc, const char *const argv[],
774 struct script_msg_head_t *sm_head)
775 {
776 const char *scriptpath;
777 int fd[2];
778 int error;
779 pid_t pid, wpid;
780
781 if ((scriptpath = argv[0]) == NULL)
782 return;
783
784 fd[0] = fd[1] = -1;
785 if (sm_head != NULL && !TAILQ_EMPTY(sm_head)) {
786 error = pipe(fd);
787 if (error) {
788 warnmsg(LOG_ERR, __func__,
789 "failed to create a pipe: %s", strerror(errno));
790 return;
791 }
792 }
793
794 /* launch the script */
795 pid = fork();
796 if (pid < 0) {
797 warnmsg(LOG_ERR, __func__,
798 "failed to fork: %s", strerror(errno));
799 return;
800 } else if (pid) { /* parent */
801 int wstatus;
802
803 if (fd[0] != -1) { /* Send message to the child if any. */
804 ssize_t len;
805 struct script_msg *smp;
806
807 close(fd[0]);
808 TAILQ_FOREACH(smp, sm_head, sm_next) {
809 len = strlen(smp->sm_msg);
810 warnmsg(LOG_DEBUG, __func__,
811 "write to child = %s(%zd)",
812 smp->sm_msg, len);
813 if (write(fd[1], smp->sm_msg, len) != len) {
814 warnmsg(LOG_ERR, __func__,
815 "write to child failed: %s",
816 strerror(errno));
817 break;
818 }
819 }
820 close(fd[1]);
821 }
822 do {
823 wpid = wait(&wstatus);
824 } while (wpid != pid && wpid > 0);
825
826 if (wpid < 0)
827 warnmsg(LOG_ERR, __func__,
828 "wait: %s", strerror(errno));
829 else
830 warnmsg(LOG_DEBUG, __func__,
831 "script \"%s\" terminated", scriptpath);
832 } else { /* child */
833 int nullfd;
834 char **_argv;
835
836 if (safefile(scriptpath)) {
837 warnmsg(LOG_ERR, __func__,
838 "script \"%s\" cannot be executed safely",
839 scriptpath);
840 exit(1);
841 }
842 nullfd = open("/dev/null", O_RDWR);
843 if (nullfd < 0) {
844 warnmsg(LOG_ERR, __func__,
845 "open /dev/null: %s", strerror(errno));
846 exit(1);
847 }
848 if (fd[0] != -1) { /* Receive message from STDIN if any. */
849 close(fd[1]);
850 if (fd[0] != STDIN_FILENO) {
851 /* Connect a pipe read-end to child's STDIN. */
852 if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) {
853 warnmsg(LOG_ERR, __func__,
854 "dup2 STDIN: %s", strerror(errno));
855 exit(1);
856 }
857 close(fd[0]);
858 }
859 } else
860 dup2(nullfd, STDIN_FILENO);
861
862 dup2(nullfd, STDOUT_FILENO);
863 dup2(nullfd, STDERR_FILENO);
864 if (nullfd > STDERR_FILENO)
865 close(nullfd);
866
867 _argv = malloc(sizeof(*_argv) * argc);
868 if (_argv == NULL) {
869 warnmsg(LOG_ERR, __func__,
870 "malloc: %s", strerror(errno));
871 exit(1);
872 }
873 memcpy(_argv, argv, (size_t)argc);
874 execv(scriptpath, (char *const *)_argv);
875 warnmsg(LOG_ERR, __func__, "child: exec failed: %s",
876 strerror(errno));
877 exit(1);
878 }
879
880 return;
881 }
882
883 static int
safefile(const char * path)884 safefile(const char *path)
885 {
886 struct stat s;
887 uid_t myuid;
888
889 /* no setuid */
890 if (getuid() != geteuid()) {
891 warnmsg(LOG_NOTICE, __func__,
892 "setuid'ed execution not allowed\n");
893 return (-1);
894 }
895
896 if (lstat(path, &s) != 0) {
897 warnmsg(LOG_NOTICE, __func__, "lstat failed: %s",
898 strerror(errno));
899 return (-1);
900 }
901
902 /* the file must be owned by the running uid */
903 myuid = getuid();
904 if (s.st_uid != myuid) {
905 warnmsg(LOG_NOTICE, __func__,
906 "%s has invalid owner uid\n", path);
907 return (-1);
908 }
909
910 switch (s.st_mode & S_IFMT) {
911 case S_IFREG:
912 break;
913 default:
914 warnmsg(LOG_NOTICE, __func__,
915 "%s is an invalid file type 0x%o\n",
916 path, (s.st_mode & S_IFMT));
917 return (-1);
918 }
919
920 return (0);
921 }
922
923 /* Decode domain name label encoding in RFC 1035 Section 3.1 */
924 static size_t
dname_labeldec(char * dst,size_t dlen,const char * src)925 dname_labeldec(char *dst, size_t dlen, const char *src)
926 {
927 size_t len;
928 const char *src_origin;
929 const char *src_last;
930 const char *dst_origin;
931
932 src_origin = src;
933 src_last = strchr(src, '\0');
934 dst_origin = dst;
935 memset(dst, '\0', dlen);
936 while ((len = (*src++) & 0x3f) &&
937 src + len <= src_last &&
938 len + 1 + (dst == dst_origin ? 0 : 1) <= dlen) {
939 if (dst != dst_origin) {
940 *dst++ = '.';
941 dlen--;
942 }
943 warnmsg(LOG_DEBUG, __func__, "labellen = %zd", len);
944 memcpy(dst, src, len);
945 src += len;
946 dst += len;
947 dlen -= len;
948 }
949 *dst = '\0';
950
951 /*
952 * XXX validate that domain name only contains valid characters
953 * for two reasons: 1) correctness, 2) we do not want to pass
954 * possible malicious, unescaped characters like `` to a script
955 * or program that could be exploited that way.
956 */
957
958 return (src - src_origin);
959 }
960