1 /* $KAME: rtsol.c,v 1.27 2003/10/05 00:09:36 itojun Exp $ */
2
3 /*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (C) 2011 Hiroki Sato
6 * 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. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: stable/10/usr.sbin/rtsold/rtsol.c 307646 2016-10-19 17:31:59Z markj $
33 */
34
35 #include <sys/param.h>
36 #include <sys/socket.h>
37 #include <sys/uio.h>
38 #include <sys/queue.h>
39 #include <sys/wait.h>
40 #include <sys/stat.h>
41
42 #include <net/if.h>
43 #include <net/route.h>
44 #include <net/if_dl.h>
45
46 #define __BSD_VISIBLE 1 /* IN6ADDR_LINKLOCAL_ALLROUTERS_INIT */
47 #include <netinet/in.h>
48 #undef __BSD_VISIBLE
49 #include <netinet/ip6.h>
50 #include <netinet6/ip6_var.h>
51 #include <netinet/icmp6.h>
52
53 #include <arpa/inet.h>
54
55 #include <netdb.h>
56 #include <time.h>
57 #include <fcntl.h>
58 #include <unistd.h>
59 #include <stdio.h>
60 #include <time.h>
61 #include <err.h>
62 #include <errno.h>
63 #include <string.h>
64 #include <stdlib.h>
65 #include <syslog.h>
66 #include "rtsold.h"
67
68 static struct msghdr rcvmhdr;
69 static struct msghdr sndmhdr;
70 static struct iovec rcviov[2];
71 static struct iovec sndiov[2];
72 static struct sockaddr_in6 from;
73 static int rcvcmsglen;
74
75 int rssock;
76 static char rsid[IFNAMSIZ + 1 + sizeof(DNSINFO_ORIGIN_LABEL) + 1 + NI_MAXHOST];
77 struct ifinfo_head_t ifinfo_head =
78 TAILQ_HEAD_INITIALIZER(ifinfo_head);
79
80 static const struct sockaddr_in6 sin6_allrouters = {
81 .sin6_len = sizeof(sin6_allrouters),
82 .sin6_family = AF_INET6,
83 .sin6_addr = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
84 };
85
86 static void call_script(const int, const char *const *,
87 struct script_msg_head_t *);
88 static size_t dname_labeldec(char *, size_t, const char *);
89 static int safefile(const char *);
90 static struct ra_opt *find_raopt(struct rainfo *, int, void *, size_t);
91 static int ra_opt_rdnss_dispatch(struct ifinfo *, struct rainfo *,
92 struct script_msg_head_t *, struct script_msg_head_t *);
93 static char *make_rsid(const char *, const char *, struct rainfo *);
94
95 #define _ARGS_OTHER otherconf_script, ifi->ifname
96 #define _ARGS_RESADD resolvconf_script, "-a", rsid
97 #define _ARGS_RESDEL resolvconf_script, "-d", rsid
98
99 #define CALL_SCRIPT(name, sm_head) \
100 do { \
101 const char *const sarg[] = { _ARGS_##name, NULL }; \
102 call_script(sizeof(sarg), sarg, sm_head); \
103 } while(0)
104
105 #define ELM_MALLOC(p,error_action) \
106 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 switch (ndo->nd_opt_type) {
407 case ND_OPT_RDNSS:
408 rdnss = (struct nd_opt_rdnss *)raoptp;
409
410 /* Optlen sanity check (Section 5.3.1 in RFC 6106) */
411 if (rdnss->nd_opt_rdnss_len < 3) {
412 warnmsg(LOG_INFO, __func__,
413 "too short RDNSS option"
414 "in RA from %s was ignored.",
415 inet_ntop(AF_INET6, &from.sin6_addr,
416 ntopbuf, sizeof(ntopbuf)));
417 break;
418 }
419
420 addr = (struct in6_addr *)(void *)(raoptp + sizeof(*rdnss));
421 while ((char *)addr < (char *)RA_OPT_NEXT_HDR(raoptp)) {
422 if (inet_ntop(AF_INET6, addr, ntopbuf,
423 sizeof(ntopbuf)) == NULL) {
424 warnmsg(LOG_INFO, __func__,
425 "an invalid address in RDNSS option"
426 " in RA from %s was ignored.",
427 inet_ntop(AF_INET6, &from.sin6_addr,
428 ntopbuf, sizeof(ntopbuf)));
429 addr++;
430 continue;
431 }
432 if (IN6_IS_ADDR_LINKLOCAL(addr))
433 /* XXX: % has to be escaped here */
434 l = snprintf(nsbuf, sizeof(nsbuf),
435 "%s%c%s", ntopbuf,
436 SCOPE_DELIMITER,
437 ifi->ifname);
438 else
439 l = snprintf(nsbuf, sizeof(nsbuf),
440 "%s", ntopbuf);
441 if (l < 0 || (size_t)l >= sizeof(nsbuf)) {
442 warnmsg(LOG_ERR, __func__,
443 "address copying error in "
444 "RDNSS option: %d.", l);
445 addr++;
446 continue;
447 }
448 warnmsg(LOG_DEBUG, __func__, "nsbuf = %s",
449 nsbuf);
450
451 newent_rao = 0;
452 rao = find_raopt(rai, ndo->nd_opt_type, nsbuf,
453 strlen(nsbuf));
454 if (rao == NULL) {
455 ELM_MALLOC(rao, break);
456 rao->rao_type = ndo->nd_opt_type;
457 rao->rao_len = strlen(nsbuf);
458 rao->rao_msg = strdup(nsbuf);
459 if (rao->rao_msg == NULL) {
460 warnmsg(LOG_ERR, __func__,
461 "strdup failed: %s",
462 strerror(errno));
463 free(rao);
464 addr++;
465 continue;
466 }
467 newent_rao = 1;
468 }
469 /* Set expiration timer */
470 memset(&rao->rao_expire, 0,
471 sizeof(rao->rao_expire));
472 memset(&lifetime, 0, sizeof(lifetime));
473 lifetime.tv_sec =
474 ntohl(rdnss->nd_opt_rdnss_lifetime);
475 TS_ADD(&now, &lifetime, &rao->rao_expire);
476
477 if (newent_rao)
478 TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
479 rao, rao_next);
480 addr++;
481 }
482 break;
483 case ND_OPT_DNSSL:
484 dnssl = (struct nd_opt_dnssl *)raoptp;
485
486 /* Optlen sanity check (Section 5.3.1 in RFC 6106) */
487 if (dnssl->nd_opt_dnssl_len < 2) {
488 warnmsg(LOG_INFO, __func__,
489 "too short DNSSL option"
490 "in RA from %s was ignored.",
491 inet_ntop(AF_INET6, &from.sin6_addr,
492 ntopbuf, sizeof(ntopbuf)));
493 break;
494 }
495
496 /*
497 * Ensure NUL-termination in DNSSL in case of
498 * malformed field.
499 */
500 p = (char *)RA_OPT_NEXT_HDR(raoptp);
501 *(p - 1) = '\0';
502
503 p = raoptp + sizeof(*dnssl);
504 while (1 < (len = dname_labeldec(dname, sizeof(dname),
505 p))) {
506 /* length == 1 means empty string */
507 warnmsg(LOG_DEBUG, __func__, "dname = %s",
508 dname);
509
510 newent_rao = 0;
511 rao = find_raopt(rai, ndo->nd_opt_type, dname,
512 strlen(dname));
513 if (rao == NULL) {
514 ELM_MALLOC(rao, break);
515 rao->rao_type = ndo->nd_opt_type;
516 rao->rao_len = strlen(dname);
517 rao->rao_msg = strdup(dname);
518 if (rao->rao_msg == NULL) {
519 warnmsg(LOG_ERR, __func__,
520 "strdup failed: %s",
521 strerror(errno));
522 free(rao);
523 addr++;
524 continue;
525 }
526 newent_rao = 1;
527 }
528 /* Set expiration timer */
529 memset(&rao->rao_expire, 0,
530 sizeof(rao->rao_expire));
531 memset(&lifetime, 0, sizeof(lifetime));
532 lifetime.tv_sec =
533 ntohl(dnssl->nd_opt_dnssl_lifetime);
534 TS_ADD(&now, &lifetime, &rao->rao_expire);
535
536 if (newent_rao)
537 TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
538 rao, rao_next);
539 p += len;
540 }
541 break;
542 default:
543 /* nothing to do for other options */
544 break;
545 }
546 raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
547 }
548 if (newent_rai)
549 TAILQ_INSERT_TAIL(&ifi->ifi_rainfo, rai, rai_next);
550
551 ra_opt_handler(ifi);
552 ifi->racnt++;
553
554 switch (ifi->state) {
555 case IFS_IDLE: /* should be ignored */
556 case IFS_DELAY: /* right? */
557 break;
558 case IFS_PROBE:
559 ifi->state = IFS_IDLE;
560 ifi->probes = 0;
561 rtsol_timer_update(ifi);
562 break;
563 }
564 }
565
566 static char resstr_ns_prefix[] = "nameserver ";
567 static char resstr_sh_prefix[] = "search ";
568 static char resstr_nl[] = "\n";
569 static char resstr_sp[] = " ";
570
571 int
ra_opt_handler(struct ifinfo * ifi)572 ra_opt_handler(struct ifinfo *ifi)
573 {
574 struct ra_opt *rao;
575 struct rainfo *rai;
576 struct script_msg *smp1, *smp2, *smp3;
577 struct timespec now;
578 struct script_msg_head_t sm_rdnss_head =
579 TAILQ_HEAD_INITIALIZER(sm_rdnss_head);
580 struct script_msg_head_t sm_dnssl_head =
581 TAILQ_HEAD_INITIALIZER(sm_dnssl_head);
582
583 int dcount, dlen;
584
585 dcount = 0;
586 dlen = strlen(resstr_sh_prefix) + strlen(resstr_nl);
587 clock_gettime(CLOCK_MONOTONIC_FAST, &now);
588
589 /*
590 * All options from multiple RAs with the same or different
591 * source addresses on a single interface will be gathered and
592 * handled, not overridden. [RFC 4861 6.3.4]
593 */
594 TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next) {
595 TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
596 switch (rao->rao_type) {
597 case ND_OPT_RDNSS:
598 if (TS_CMP(&now, &rao->rao_expire, >)) {
599 warnmsg(LOG_INFO, __func__,
600 "expired rdnss entry: %s",
601 (char *)rao->rao_msg);
602 break;
603 }
604 ELM_MALLOC(smp1, continue);
605 ELM_MALLOC(smp2, goto free1);
606 ELM_MALLOC(smp3, goto free2);
607 smp1->sm_msg = resstr_ns_prefix;
608 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp1,
609 sm_next);
610 smp2->sm_msg = rao->rao_msg;
611 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp2,
612 sm_next);
613 smp3->sm_msg = resstr_nl;
614 TAILQ_INSERT_TAIL(&sm_rdnss_head, smp3,
615 sm_next);
616 ifi->ifi_rdnss = IFI_DNSOPT_STATE_RECEIVED;
617
618 break;
619 case ND_OPT_DNSSL:
620 if (TS_CMP(&now, &rao->rao_expire, >)) {
621 warnmsg(LOG_INFO, __func__,
622 "expired dnssl entry: %s",
623 (char *)rao->rao_msg);
624 break;
625 }
626 dcount++;
627 /* Check resolv.conf(5) restrictions. */
628 if (dcount > 6) {
629 warnmsg(LOG_INFO, __func__,
630 "dnssl entry exceeding maximum count (%d>6)"
631 ": %s", dcount, (char *)rao->rao_msg);
632 break;
633 }
634 if (256 < dlen + strlen(rao->rao_msg) +
635 strlen(resstr_sp)) {
636 warnmsg(LOG_INFO, __func__,
637 "dnssl entry exceeding maximum length "
638 "(>256): %s", (char *)rao->rao_msg);
639 break;
640 }
641 ELM_MALLOC(smp1, continue);
642 ELM_MALLOC(smp2, goto free1);
643 if (TAILQ_EMPTY(&sm_dnssl_head)) {
644 ELM_MALLOC(smp3, goto free2);
645 smp3->sm_msg = resstr_sh_prefix;
646 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp3,
647 sm_next);
648 }
649 smp1->sm_msg = rao->rao_msg;
650 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1,
651 sm_next);
652 smp2->sm_msg = resstr_sp;
653 TAILQ_INSERT_TAIL(&sm_dnssl_head, smp2,
654 sm_next);
655 dlen += strlen(rao->rao_msg) +
656 strlen(resstr_sp);
657 break;
658
659 ifi->ifi_dnssl = IFI_DNSOPT_STATE_RECEIVED;
660 default:
661 break;
662 }
663 continue;
664 free2:
665 free(smp2);
666 free1:
667 free(smp1);
668 }
669 /* Call the script for each information source. */
670 if (uflag)
671 ra_opt_rdnss_dispatch(ifi, rai, &sm_rdnss_head,
672 &sm_dnssl_head);
673 }
674 /* Call the script for each interface. */
675 if (!uflag)
676 ra_opt_rdnss_dispatch(ifi, NULL, &sm_rdnss_head,
677 &sm_dnssl_head);
678 return (0);
679 }
680
681 char *
make_rsid(const char * ifname,const char * origin,struct rainfo * rai)682 make_rsid(const char *ifname, const char *origin, struct rainfo *rai)
683 {
684 char hbuf[NI_MAXHOST];
685
686 if (rai == NULL)
687 sprintf(rsid, "%s:%s", ifname, origin);
688 else {
689 if (!IN6_IS_ADDR_LINKLOCAL(&rai->rai_saddr.sin6_addr))
690 return (NULL);
691 if (getnameinfo((struct sockaddr *)&rai->rai_saddr,
692 rai->rai_saddr.sin6_len, hbuf, sizeof(hbuf), NULL, 0,
693 NI_NUMERICHOST) != 0)
694 return (NULL);
695 sprintf(rsid, "%s:%s:[%s]", ifname, origin, hbuf);
696 }
697 warnmsg(LOG_DEBUG, __func__, "rsid = [%s]", rsid);
698 return (rsid);
699 }
700
701 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)702 ra_opt_rdnss_dispatch(struct ifinfo *ifi,
703 struct rainfo *rai,
704 struct script_msg_head_t *sm_rdnss_head,
705 struct script_msg_head_t *sm_dnssl_head)
706 {
707 const char *r;
708 struct script_msg *smp1;
709 int error;
710
711 error = 0;
712 /* Add \n for DNSSL list. */
713 if (!TAILQ_EMPTY(sm_dnssl_head)) {
714 ELM_MALLOC(smp1, goto ra_opt_rdnss_freeit);
715 smp1->sm_msg = resstr_nl;
716 TAILQ_INSERT_TAIL(sm_dnssl_head, smp1, sm_next);
717 }
718 TAILQ_CONCAT(sm_rdnss_head, sm_dnssl_head, sm_next);
719
720 if (rai != NULL && uflag)
721 r = make_rsid(ifi->ifname, DNSINFO_ORIGIN_LABEL, rai);
722 else
723 r = make_rsid(ifi->ifname, DNSINFO_ORIGIN_LABEL, NULL);
724 if (r == NULL) {
725 warnmsg(LOG_ERR, __func__, "make_rsid() failed. "
726 "Script was not invoked.");
727 error = 1;
728 goto ra_opt_rdnss_freeit;
729 }
730 if (!TAILQ_EMPTY(sm_rdnss_head))
731 CALL_SCRIPT(RESADD, sm_rdnss_head);
732 else if (ifi->ifi_rdnss == IFI_DNSOPT_STATE_RECEIVED ||
733 ifi->ifi_dnssl == IFI_DNSOPT_STATE_RECEIVED) {
734 CALL_SCRIPT(RESDEL, NULL);
735 ifi->ifi_rdnss = IFI_DNSOPT_STATE_NOINFO;
736 ifi->ifi_dnssl = IFI_DNSOPT_STATE_NOINFO;
737 }
738
739 ra_opt_rdnss_freeit:
740 /* Clear script message queue. */
741 if (!TAILQ_EMPTY(sm_rdnss_head)) {
742 while ((smp1 = TAILQ_FIRST(sm_rdnss_head)) != NULL) {
743 TAILQ_REMOVE(sm_rdnss_head, smp1, sm_next);
744 free(smp1);
745 }
746 }
747 if (!TAILQ_EMPTY(sm_dnssl_head)) {
748 while ((smp1 = TAILQ_FIRST(sm_dnssl_head)) != NULL) {
749 TAILQ_REMOVE(sm_dnssl_head, smp1, sm_next);
750 free(smp1);
751 }
752 }
753 return (error);
754 }
755
756 static struct ra_opt *
find_raopt(struct rainfo * rai,int type,void * msg,size_t len)757 find_raopt(struct rainfo *rai, int type, void *msg, size_t len)
758 {
759 struct ra_opt *rao;
760
761 TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
762 if (rao->rao_type == type &&
763 rao->rao_len == strlen(msg) &&
764 memcmp(rao->rao_msg, msg, len) == 0)
765 break;
766 }
767
768 return (rao);
769 }
770
771 static void
call_script(const int argc,const char * const argv[],struct script_msg_head_t * sm_head)772 call_script(const int argc, const char *const argv[],
773 struct script_msg_head_t *sm_head)
774 {
775 const char *scriptpath;
776 int fd[2];
777 int error;
778 pid_t pid, wpid;
779
780 if ((scriptpath = argv[0]) == NULL)
781 return;
782
783 fd[0] = fd[1] = -1;
784 if (sm_head != NULL && !TAILQ_EMPTY(sm_head)) {
785 error = pipe(fd);
786 if (error) {
787 warnmsg(LOG_ERR, __func__,
788 "failed to create a pipe: %s", strerror(errno));
789 return;
790 }
791 }
792
793 /* launch the script */
794 pid = fork();
795 if (pid < 0) {
796 warnmsg(LOG_ERR, __func__,
797 "failed to fork: %s", strerror(errno));
798 return;
799 } else if (pid) { /* parent */
800 int wstatus;
801
802 if (fd[0] != -1) { /* Send message to the child if any. */
803 ssize_t len;
804 struct script_msg *smp;
805
806 close(fd[0]);
807 TAILQ_FOREACH(smp, sm_head, sm_next) {
808 len = strlen(smp->sm_msg);
809 warnmsg(LOG_DEBUG, __func__,
810 "write to child = %s(%zd)",
811 smp->sm_msg, len);
812 if (write(fd[1], smp->sm_msg, len) != len) {
813 warnmsg(LOG_ERR, __func__,
814 "write to child failed: %s",
815 strerror(errno));
816 break;
817 }
818 }
819 close(fd[1]);
820 }
821 do {
822 wpid = wait(&wstatus);
823 } while (wpid != pid && wpid > 0);
824
825 if (wpid < 0)
826 warnmsg(LOG_ERR, __func__,
827 "wait: %s", strerror(errno));
828 else
829 warnmsg(LOG_DEBUG, __func__,
830 "script \"%s\" terminated", scriptpath);
831 } else { /* child */
832 int nullfd;
833 char **_argv;
834
835 if (safefile(scriptpath)) {
836 warnmsg(LOG_ERR, __func__,
837 "script \"%s\" cannot be executed safely",
838 scriptpath);
839 exit(1);
840 }
841 nullfd = open("/dev/null", O_RDWR);
842 if (nullfd < 0) {
843 warnmsg(LOG_ERR, __func__,
844 "open /dev/null: %s", strerror(errno));
845 exit(1);
846 }
847 if (fd[0] != -1) { /* Receive message from STDIN if any. */
848 close(fd[1]);
849 if (fd[0] != STDIN_FILENO) {
850 /* Connect a pipe read-end to child's STDIN. */
851 if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) {
852 warnmsg(LOG_ERR, __func__,
853 "dup2 STDIN: %s", strerror(errno));
854 exit(1);
855 }
856 close(fd[0]);
857 }
858 } else
859 dup2(nullfd, STDIN_FILENO);
860
861 dup2(nullfd, STDOUT_FILENO);
862 dup2(nullfd, STDERR_FILENO);
863 if (nullfd > STDERR_FILENO)
864 close(nullfd);
865
866 _argv = malloc(sizeof(*_argv) * argc);
867 if (_argv == NULL) {
868 warnmsg(LOG_ERR, __func__,
869 "malloc: %s", strerror(errno));
870 exit(1);
871 }
872 memcpy(_argv, argv, (size_t)argc);
873 execv(scriptpath, (char *const *)_argv);
874 warnmsg(LOG_ERR, __func__, "child: exec failed: %s",
875 strerror(errno));
876 exit(1);
877 }
878
879 return;
880 }
881
882 static int
safefile(const char * path)883 safefile(const char *path)
884 {
885 struct stat s;
886 uid_t myuid;
887
888 /* no setuid */
889 if (getuid() != geteuid()) {
890 warnmsg(LOG_NOTICE, __func__,
891 "setuid'ed execution not allowed\n");
892 return (-1);
893 }
894
895 if (lstat(path, &s) != 0) {
896 warnmsg(LOG_NOTICE, __func__, "lstat failed: %s",
897 strerror(errno));
898 return (-1);
899 }
900
901 /* the file must be owned by the running uid */
902 myuid = getuid();
903 if (s.st_uid != myuid) {
904 warnmsg(LOG_NOTICE, __func__,
905 "%s has invalid owner uid\n", path);
906 return (-1);
907 }
908
909 switch (s.st_mode & S_IFMT) {
910 case S_IFREG:
911 break;
912 default:
913 warnmsg(LOG_NOTICE, __func__,
914 "%s is an invalid file type 0x%o\n",
915 path, (s.st_mode & S_IFMT));
916 return (-1);
917 }
918
919 return (0);
920 }
921
922 /* Decode domain name label encoding in RFC 1035 Section 3.1 */
923 static size_t
dname_labeldec(char * dst,size_t dlen,const char * src)924 dname_labeldec(char *dst, size_t dlen, const char *src)
925 {
926 size_t len;
927 const char *src_origin;
928 const char *src_last;
929 const char *dst_origin;
930
931 src_origin = src;
932 src_last = strchr(src, '\0');
933 dst_origin = dst;
934 memset(dst, '\0', dlen);
935 while (src && (len = (uint8_t)(*src++) & 0x3f) &&
936 (src + len) <= src_last &&
937 (dst - dst_origin < (ssize_t)dlen)) {
938 if (dst != dst_origin)
939 *dst++ = '.';
940 warnmsg(LOG_DEBUG, __func__, "labellen = %zd", len);
941 memcpy(dst, src, len);
942 src += len;
943 dst += len;
944 }
945 *dst = '\0';
946
947 /*
948 * XXX validate that domain name only contains valid characters
949 * for two reasons: 1) correctness, 2) we do not want to pass
950 * possible malicious, unescaped characters like `` to a script
951 * or program that could be exploited that way.
952 */
953
954 return (src - src_origin);
955 }
956