rtsol.c revision 222861 
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: head/usr.sbin/rtsold/rtsol.c 222861 2011-06-08 16:03:29Z hrs $
33 */
34
35#include <sys/param.h>
36#include <sys/socket.h>
37#include <sys/uio.h>
38#include <sys/time.h>
39#include <sys/queue.h>
40#include <sys/wait.h>
41#include <sys/stat.h>
42
43#include <net/if.h>
44#include <net/route.h>
45#include <net/if_dl.h>
46
47#define	__BSD_VISIBLE	1	/* IN6ADDR_LINKLOCAL_ALLROUTERS_INIT */
48#include <netinet/in.h>
49#undef 	__BSD_VISIBLE
50#include <netinet/ip6.h>
51#include <netinet6/ip6_var.h>
52#include <netinet/icmp6.h>
53
54#include <arpa/inet.h>
55
56#include <netdb.h>
57#include <time.h>
58#include <fcntl.h>
59#include <unistd.h>
60#include <stdio.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
68static struct msghdr rcvmhdr;
69static struct msghdr sndmhdr;
70static struct iovec rcviov[2];
71static struct iovec sndiov[2];
72static struct sockaddr_in6 from;
73static int rcvcmsglen;
74
75int rssock;
76struct ifinfo_head_t ifinfo_head =
77	TAILQ_HEAD_INITIALIZER(ifinfo_head);
78
79static const struct sockaddr_in6 sin6_allrouters = {
80	.sin6_len =	sizeof(sin6_allrouters),
81	.sin6_family =	AF_INET6,
82	.sin6_addr =	IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
83};
84
85static void call_script(const int, const char *const *, void *);
86static size_t dname_labeldec(char *, size_t, const char *);
87static int safefile(const char *);
88static struct ra_opt *find_raopt(struct rainfo *, int, void *, size_t);
89
90#define	_ARGS_OTHER	otherconf_script, ifi->ifname
91#define	_ARGS_RESADD	resolvconf_script, "-a", ifi->ifname
92#define	_ARGS_RESDEL	resolvconf_script, "-d", ifi->ifname
93
94#define	CALL_SCRIPT(name, sm_head)					\
95	do {								\
96		const char *const sarg[] = { _ARGS_##name, NULL };	\
97		call_script(sizeof(sarg), sarg, sm_head);		\
98	} while(0)
99
100#define	ELM_MALLOC(p,error_action)					\
101	do {								\
102		p = malloc(sizeof(*p));					\
103		if (p == NULL) {					\
104			warnmsg(LOG_ERR, __func__, "malloc failed: %s", \
105				strerror(errno));			\
106			error_action;					\
107		}							\
108		memset(p, 0, sizeof(*p));				\
109	} while(0)
110
111int
112sockopen(void)
113{
114	static u_char *rcvcmsgbuf = NULL, *sndcmsgbuf = NULL;
115	int sndcmsglen, on;
116	static u_char answer[1500];
117	struct icmp6_filter filt;
118
119	sndcmsglen = rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
120	    CMSG_SPACE(sizeof(int));
121	if (rcvcmsgbuf == NULL && (rcvcmsgbuf = malloc(rcvcmsglen)) == NULL) {
122		warnmsg(LOG_ERR, __func__,
123		    "malloc for receive msghdr failed");
124		return (-1);
125	}
126	if (sndcmsgbuf == NULL && (sndcmsgbuf = malloc(sndcmsglen)) == NULL) {
127		warnmsg(LOG_ERR, __func__,
128		    "malloc for send msghdr failed");
129		return (-1);
130	}
131	if ((rssock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
132		warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
133		return (-1);
134	}
135
136	/* specify to tell receiving interface */
137	on = 1;
138	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
139	    sizeof(on)) < 0) {
140		warnmsg(LOG_ERR, __func__, "IPV6_RECVPKTINFO: %s",
141		    strerror(errno));
142		exit(1);
143	}
144
145	/* specify to tell value of hoplimit field of received IP6 hdr */
146	on = 1;
147	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
148	    sizeof(on)) < 0) {
149		warnmsg(LOG_ERR, __func__, "IPV6_RECVHOPLIMIT: %s",
150		    strerror(errno));
151		exit(1);
152	}
153
154	/* specfiy to accept only router advertisements on the socket */
155	ICMP6_FILTER_SETBLOCKALL(&filt);
156	ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
157	if (setsockopt(rssock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
158	    sizeof(filt)) == -1) {
159		warnmsg(LOG_ERR, __func__, "setsockopt(ICMP6_FILTER): %s",
160		    strerror(errno));
161		return(-1);
162	}
163
164	/* initialize msghdr for receiving packets */
165	rcviov[0].iov_base = (caddr_t)answer;
166	rcviov[0].iov_len = sizeof(answer);
167	rcvmhdr.msg_name = (caddr_t)&from;
168	rcvmhdr.msg_iov = rcviov;
169	rcvmhdr.msg_iovlen = 1;
170	rcvmhdr.msg_control = (caddr_t) rcvcmsgbuf;
171
172	/* initialize msghdr for sending packets */
173	sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
174	sndmhdr.msg_iov = sndiov;
175	sndmhdr.msg_iovlen = 1;
176	sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
177	sndmhdr.msg_controllen = sndcmsglen;
178
179	return (rssock);
180}
181
182void
183sendpacket(struct ifinfo *ifi)
184{
185	struct in6_pktinfo *pi;
186	struct cmsghdr *cm;
187	int hoplimit = 255;
188	ssize_t i;
189	struct sockaddr_in6 dst;
190
191	dst = sin6_allrouters;
192	dst.sin6_scope_id = ifi->linkid;
193
194	sndmhdr.msg_name = (caddr_t)&dst;
195	sndmhdr.msg_iov[0].iov_base = (caddr_t)ifi->rs_data;
196	sndmhdr.msg_iov[0].iov_len = ifi->rs_datalen;
197
198	cm = CMSG_FIRSTHDR(&sndmhdr);
199	/* specify the outgoing interface */
200	cm->cmsg_level = IPPROTO_IPV6;
201	cm->cmsg_type = IPV6_PKTINFO;
202	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
203	pi = (struct in6_pktinfo *)CMSG_DATA(cm);
204	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
205	pi->ipi6_ifindex = ifi->sdl->sdl_index;
206
207	/* specify the hop limit of the packet */
208	cm = CMSG_NXTHDR(&sndmhdr, cm);
209	cm->cmsg_level = IPPROTO_IPV6;
210	cm->cmsg_type = IPV6_HOPLIMIT;
211	cm->cmsg_len = CMSG_LEN(sizeof(int));
212	memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
213
214	warnmsg(LOG_DEBUG, __func__,
215	    "send RS on %s, whose state is %d",
216	    ifi->ifname, ifi->state);
217	i = sendmsg(rssock, &sndmhdr, 0);
218	if (i < 0 || (size_t)i != ifi->rs_datalen) {
219		/*
220		 * ENETDOWN is not so serious, especially when using several
221		 * network cards on a mobile node. We ignore it.
222		 */
223		if (errno != ENETDOWN || dflag > 0)
224			warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
225			    ifi->ifname, strerror(errno));
226	}
227
228	/* update counter */
229	ifi->probes++;
230}
231
232void
233rtsol_input(int s)
234{
235	u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
236	int l, ifindex = 0, *hlimp = NULL;
237	ssize_t msglen;
238	struct in6_pktinfo *pi = NULL;
239	struct ifinfo *ifi = NULL;
240	struct ra_opt *rao = NULL;
241	struct icmp6_hdr *icp;
242	struct nd_router_advert *nd_ra;
243	struct cmsghdr *cm;
244	struct rainfo *rai;
245	char *raoptp;
246	char *p;
247	struct in6_addr *addr;
248	struct nd_opt_hdr *ndo;
249	struct nd_opt_rdnss *rdnss;
250	struct nd_opt_dnssl *dnssl;
251	size_t len;
252	char nsbuf[INET6_ADDRSTRLEN + 1 + IFNAMSIZ + 1];
253	char dname[NI_MAXHOST];
254	struct timeval now;
255	struct timeval lifetime;
256	int newent_rai;
257	int newent_rao;
258
259	/* get message.  namelen and controllen must always be initialized. */
260	rcvmhdr.msg_namelen = sizeof(from);
261	rcvmhdr.msg_controllen = rcvcmsglen;
262	if ((msglen = recvmsg(s, &rcvmhdr, 0)) < 0) {
263		warnmsg(LOG_ERR, __func__, "recvmsg: %s", strerror(errno));
264		return;
265	}
266
267	/* extract optional information via Advanced API */
268	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&rcvmhdr); cm;
269	    cm = (struct cmsghdr *)CMSG_NXTHDR(&rcvmhdr, cm)) {
270		if (cm->cmsg_level == IPPROTO_IPV6 &&
271		    cm->cmsg_type == IPV6_PKTINFO &&
272		    cm->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) {
273			pi = (struct in6_pktinfo *)(CMSG_DATA(cm));
274			ifindex = pi->ipi6_ifindex;
275		}
276		if (cm->cmsg_level == IPPROTO_IPV6 &&
277		    cm->cmsg_type == IPV6_HOPLIMIT &&
278		    cm->cmsg_len == CMSG_LEN(sizeof(int)))
279			hlimp = (int *)CMSG_DATA(cm);
280	}
281
282	if (ifindex == 0) {
283		warnmsg(LOG_ERR, __func__,
284		    "failed to get receiving interface");
285		return;
286	}
287	if (hlimp == NULL) {
288		warnmsg(LOG_ERR, __func__,
289		    "failed to get receiving hop limit");
290		return;
291	}
292
293	if ((size_t)msglen < sizeof(struct nd_router_advert)) {
294		warnmsg(LOG_INFO, __func__,
295		    "packet size(%zd) is too short", msglen);
296		return;
297	}
298
299	icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;
300
301	if (icp->icmp6_type != ND_ROUTER_ADVERT) {
302		/*
303		 * this should not happen because we configured a filter
304		 * that only passes RAs on the receiving socket.
305		 */
306		warnmsg(LOG_ERR, __func__,
307		    "invalid icmp type(%d) from %s on %s", icp->icmp6_type,
308		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
309		    INET6_ADDRSTRLEN),
310		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
311		return;
312	}
313
314	if (icp->icmp6_code != 0) {
315		warnmsg(LOG_INFO, __func__,
316		    "invalid icmp code(%d) from %s on %s", icp->icmp6_code,
317		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
318		    INET6_ADDRSTRLEN),
319		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
320		return;
321	}
322
323	if (*hlimp != 255) {
324		warnmsg(LOG_INFO, __func__,
325		    "invalid RA with hop limit(%d) from %s on %s",
326		    *hlimp,
327		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
328		    INET6_ADDRSTRLEN),
329		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
330		return;
331	}
332
333	if (pi && !IN6_IS_ADDR_LINKLOCAL(&from.sin6_addr)) {
334		warnmsg(LOG_INFO, __func__,
335		    "invalid RA with non link-local source from %s on %s",
336		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
337		    INET6_ADDRSTRLEN),
338		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
339		return;
340	}
341
342	/* xxx: more validation? */
343
344	if ((ifi = find_ifinfo(pi->ipi6_ifindex)) == NULL) {
345		warnmsg(LOG_INFO, __func__,
346		    "received RA from %s on an unexpected IF(%s)",
347		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
348		    INET6_ADDRSTRLEN),
349		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
350		return;
351	}
352
353	warnmsg(LOG_DEBUG, __func__,
354	    "received RA from %s on %s, state is %d",
355	    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf, INET6_ADDRSTRLEN),
356	    ifi->ifname, ifi->state);
357
358	nd_ra = (struct nd_router_advert *)icp;
359
360	/*
361	 * Process the "O bit."
362	 * If the value of OtherConfigFlag changes from FALSE to TRUE, the
363	 * host should invoke the stateful autoconfiguration protocol,
364	 * requesting information.
365	 * [RFC 2462 Section 5.5.3]
366	 */
367	if (((nd_ra->nd_ra_flags_reserved) & ND_RA_FLAG_OTHER) &&
368	    !ifi->otherconfig) {
369		warnmsg(LOG_DEBUG, __func__,
370		    "OtherConfigFlag on %s is turned on", ifi->ifname);
371		ifi->otherconfig = 1;
372		CALL_SCRIPT(OTHER, NULL);
373	}
374	gettimeofday(&now, NULL);
375	newent_rai = 0;
376	rai = find_rainfo(ifi, &from);
377	if (rai == NULL) {
378		ELM_MALLOC(rai, exit(1));
379		rai->rai_ifinfo = ifi;
380		TAILQ_INIT(&rai->rai_ra_opt);
381		memcpy(&rai->rai_saddr.sin6_addr, &from.sin6_addr,
382		    sizeof(rai->rai_saddr.sin6_addr));
383		newent_rai = 1;
384	}
385
386#define	RA_OPT_NEXT_HDR(x)	(struct nd_opt_hdr *)((char *)x + \
387				(((struct nd_opt_hdr *)x)->nd_opt_len * 8))
388	/* Process RA options. */
389	warnmsg(LOG_DEBUG, __func__, "Processing RA");
390	raoptp = (char *)icp + sizeof(struct nd_router_advert);
391	while (raoptp < (char *)icp + msglen) {
392		ndo = (struct nd_opt_hdr *)raoptp;
393		warnmsg(LOG_DEBUG, __func__, "ndo = %p", raoptp);
394		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_type = %d",
395		    ndo->nd_opt_type);
396		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_len = %d",
397		    ndo->nd_opt_len);
398
399		switch (ndo->nd_opt_type) {
400		case ND_OPT_RDNSS:
401			rdnss = (struct nd_opt_rdnss *)raoptp;
402
403			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
404			if (rdnss->nd_opt_rdnss_len < 3) {
405				warnmsg(LOG_INFO, __func__,
406		    			"too short RDNSS option"
407					"in RA from %s was ignored.",
408					inet_ntop(AF_INET6, &from.sin6_addr,
409						  ntopbuf, INET6_ADDRSTRLEN));
410				break;
411			}
412
413			addr = (struct in6_addr *)(raoptp + sizeof(*rdnss));
414			while ((char *)addr < (char *)RA_OPT_NEXT_HDR(raoptp)) {
415				if (inet_ntop(AF_INET6, addr, ntopbuf,
416				    INET6_ADDRSTRLEN) == NULL) {
417					warnmsg(LOG_INFO, __func__,
418		    			    "an invalid address in RDNSS option"
419					    " in RA from %s was ignored.",
420					    inet_ntop(AF_INET6, &from.sin6_addr,
421					    ntopbuf, INET6_ADDRSTRLEN));
422					addr++;
423					continue;
424				}
425				if (IN6_IS_ADDR_LINKLOCAL(addr))
426					/* XXX: % has to be escaped here */
427					l = snprintf(nsbuf, sizeof(nsbuf),
428					    "%s%c%s", ntopbuf,
429					    SCOPE_DELIMITER,
430					    ifi->ifname);
431				else
432					l = snprintf(nsbuf, sizeof(nsbuf),
433					    "%s", ntopbuf);
434				if (l < 0 || (size_t)l >= sizeof(nsbuf)) {
435					warnmsg(LOG_ERR, __func__,
436					    "address copying error in "
437					    "RDNSS option: %d.", l);
438					addr++;
439					continue;
440				}
441				warnmsg(LOG_DEBUG, __func__, "nsbuf = %s",
442				    nsbuf);
443
444				newent_rao = 0;
445				rao = find_raopt(rai, ndo->nd_opt_type, nsbuf,
446				    strlen(nsbuf));
447				if (rao == NULL) {
448					ELM_MALLOC(rao, break);
449					rao->rao_type = ndo->nd_opt_type;
450					rao->rao_len = strlen(nsbuf);
451					rao->rao_msg = strdup(nsbuf);
452					if (rao->rao_msg == NULL) {
453						warnmsg(LOG_ERR, __func__,
454						    "strdup failed: %s",
455						    strerror(errno));
456						free(rao);
457						addr++;
458						continue;
459					}
460					newent_rao = 1;
461				}
462				/* Set expiration timer */
463				memset(&rao->rao_expire, 0,
464				    sizeof(rao->rao_expire));
465				memset(&lifetime, 0, sizeof(lifetime));
466				lifetime.tv_sec =
467				    ntohl(rdnss->nd_opt_rdnss_lifetime);
468				timeradd(&now, &lifetime, &rao->rao_expire);
469
470				if (newent_rao)
471					TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
472					    rao, rao_next);
473				addr++;
474			}
475			break;
476		case ND_OPT_DNSSL:
477			dnssl = (struct nd_opt_dnssl *)raoptp;
478
479			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
480			if (dnssl->nd_opt_dnssl_len < 2) {
481				warnmsg(LOG_INFO, __func__,
482		    			"too short DNSSL option"
483					"in RA from %s was ignored.",
484					inet_ntop(AF_INET6, &from.sin6_addr,
485						  ntopbuf, INET6_ADDRSTRLEN));
486				break;
487			}
488
489			/*
490			 * Ensure NUL-termination in DNSSL in case of
491			 * malformed field.
492			 */
493			p = (char *)RA_OPT_NEXT_HDR(raoptp);
494			*(p - 1) = '\0';
495
496			p = raoptp + sizeof(*dnssl);
497			while (1 < (len = dname_labeldec(dname, sizeof(dname),
498			    p))) {
499				/* length == 1 means empty string */
500				warnmsg(LOG_DEBUG, __func__, "dname = %s",
501				    dname);
502
503				newent_rao = 0;
504				rao = find_raopt(rai, ndo->nd_opt_type, dname,
505				    strlen(dname));
506				if (rao == NULL) {
507					ELM_MALLOC(rao, break);
508					rao->rao_type = ndo->nd_opt_type;
509					rao->rao_len = strlen(dname);
510					rao->rao_msg = strdup(dname);
511					if (rao->rao_msg == NULL) {
512						warnmsg(LOG_ERR, __func__,
513						    "strdup failed: %s",
514						    strerror(errno));
515						free(rao);
516						addr++;
517						continue;
518					}
519					newent_rao = 1;
520				}
521				/* Set expiration timer */
522				memset(&rao->rao_expire, 0,
523				    sizeof(rao->rao_expire));
524				memset(&lifetime, 0, sizeof(lifetime));
525				lifetime.tv_sec =
526				    ntohl(dnssl->nd_opt_dnssl_lifetime);
527				timeradd(&now, &lifetime, &rao->rao_expire);
528
529				if (newent_rao)
530					TAILQ_INSERT_TAIL(&rai->rai_ra_opt,
531					    rao, rao_next);
532				p += len;
533			}
534			break;
535		default:
536			/* nothing to do for other options */
537			break;
538		}
539		raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
540	}
541	if (newent_rai)
542		TAILQ_INSERT_TAIL(&ifi->ifi_rainfo, rai, rai_next);
543
544	ra_opt_handler(ifi);
545	ifi->racnt++;
546
547	switch (ifi->state) {
548	case IFS_IDLE:		/* should be ignored */
549	case IFS_DELAY:		/* right? */
550		break;
551	case IFS_PROBE:
552		ifi->state = IFS_IDLE;
553		ifi->probes = 0;
554		rtsol_timer_update(ifi);
555		break;
556	}
557}
558
559static char resstr_ns_prefix[] = "nameserver ";
560static char resstr_sh_prefix[] = "search ";
561static char resstr_nl[] = "\n";
562static char resstr_sp[] = " ";
563
564int
565ra_opt_handler(struct ifinfo *ifi)
566{
567	struct ra_opt *rao;
568	struct rainfo *rai;
569	struct script_msg *smp1, *smp2, *smp3;
570	struct timeval now;
571	TAILQ_HEAD(, script_msg) sm_rdnss_head =
572		TAILQ_HEAD_INITIALIZER(sm_rdnss_head);
573	TAILQ_HEAD(, script_msg) sm_dnssl_head =
574		TAILQ_HEAD_INITIALIZER(sm_dnssl_head);
575	int dcount, dlen;
576
577	dcount = 0;
578	dlen = strlen(resstr_sh_prefix) + strlen(resstr_nl);
579	gettimeofday(&now, NULL);
580
581	/*
582	 * All options from multiple RAs with the same or different
583	 * source addresses on a single interface will be gathered and
584	 * handled, not overridden.  [RFC 4861 6.3.4]
585	 */
586	TAILQ_FOREACH(rai, &ifi->ifi_rainfo, rai_next) {
587		TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
588			switch (rao->rao_type) {
589			case ND_OPT_RDNSS:
590				if (timercmp(&now, &rao->rao_expire, >)) {
591					warnmsg(LOG_INFO, __func__,
592					    "expired rdnss entry: %s",
593					    (char *)rao->rao_msg);
594					break;
595				}
596				ELM_MALLOC(smp1, continue);
597				ELM_MALLOC(smp2, goto free1);
598				ELM_MALLOC(smp3, goto free2);
599				smp1->sm_msg = resstr_ns_prefix;
600				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp1,
601				    sm_next);
602				smp2->sm_msg = rao->rao_msg;
603				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp2,
604				    sm_next);
605				smp3->sm_msg = resstr_nl;
606				TAILQ_INSERT_TAIL(&sm_rdnss_head, smp3,
607				    sm_next);
608				ifi->ifi_rdnss = IFI_DNSOPT_STATE_RECEIVED;
609
610				break;
611			case ND_OPT_DNSSL:
612				if (timercmp(&now, &rao->rao_expire, >)) {
613					warnmsg(LOG_INFO, __func__,
614					    "expired dnssl entry: %s",
615					    (char *)rao->rao_msg);
616					break;
617				}
618				dcount++;
619				/* Check resolv.conf(5) restrictions. */
620				if (dcount > 6) {
621					warnmsg(LOG_INFO, __func__,
622					    "dnssl entry exceeding maximum count (%d>6)"
623					    ": %s", dcount, (char *)rao->rao_msg);
624					break;
625				}
626				if (256 < dlen + strlen(rao->rao_msg) +
627				    strlen(resstr_sp)) {
628					warnmsg(LOG_INFO, __func__,
629					    "dnssl entry exceeding maximum length "
630					    "(>256): %s", (char *)rao->rao_msg);
631					break;
632				}
633				ELM_MALLOC(smp1, continue);
634				ELM_MALLOC(smp2, goto free1);
635				if (TAILQ_EMPTY(&sm_dnssl_head)) {
636					ELM_MALLOC(smp3, goto free2);
637					smp3->sm_msg = resstr_sh_prefix;
638					TAILQ_INSERT_TAIL(&sm_dnssl_head, smp3,
639					    sm_next);
640				}
641				smp1->sm_msg = rao->rao_msg;
642				TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1,
643				    sm_next);
644				smp2->sm_msg = resstr_sp;
645				TAILQ_INSERT_TAIL(&sm_dnssl_head, smp2,
646				    sm_next);
647				dlen += strlen(rao->rao_msg) +
648				    strlen(resstr_sp);
649				break;
650
651				ifi->ifi_dnssl = IFI_DNSOPT_STATE_RECEIVED;
652			default:
653				break;
654			}
655			continue;
656free2:
657			free(smp2);
658free1:
659			free(smp1);
660		}
661	}
662	/* Add \n for DNSSL list. */
663	if (!TAILQ_EMPTY(&sm_dnssl_head)) {
664		ELM_MALLOC(smp1, goto ra_opt_handler_freeit);
665		smp1->sm_msg = resstr_nl;
666		TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1, sm_next);
667	}
668	TAILQ_CONCAT(&sm_rdnss_head, &sm_dnssl_head, sm_next);
669
670	if (!TAILQ_EMPTY(&sm_rdnss_head))
671		CALL_SCRIPT(RESADD, &sm_rdnss_head);
672	else if (ifi->ifi_rdnss == IFI_DNSOPT_STATE_RECEIVED ||
673	    ifi->ifi_dnssl == IFI_DNSOPT_STATE_RECEIVED) {
674		CALL_SCRIPT(RESDEL, NULL);
675		ifi->ifi_rdnss = IFI_DNSOPT_STATE_NOINFO;
676		ifi->ifi_dnssl = IFI_DNSOPT_STATE_NOINFO;
677	}
678
679ra_opt_handler_freeit:
680	/* Clear script message queue. */
681	if (!TAILQ_EMPTY(&sm_rdnss_head)) {
682		while ((smp1 = TAILQ_FIRST(&sm_rdnss_head)) != NULL) {
683			TAILQ_REMOVE(&sm_rdnss_head, smp1, sm_next);
684			free(smp1);
685		}
686	}
687	if (!TAILQ_EMPTY(&sm_dnssl_head)) {
688		while ((smp1 = TAILQ_FIRST(&sm_dnssl_head)) != NULL) {
689			TAILQ_REMOVE(&sm_dnssl_head, smp1, sm_next);
690			free(smp1);
691		}
692	}
693	return (0);
694}
695
696static struct ra_opt *
697find_raopt(struct rainfo *rai, int type, void *msg, size_t len)
698{
699	struct ra_opt *rao;
700
701	TAILQ_FOREACH(rao, &rai->rai_ra_opt, rao_next) {
702		if (rao->rao_type == type &&
703		    rao->rao_len == strlen(msg) &&
704		    memcmp(rao->rao_msg, msg, len) == 0)
705			break;
706	}
707
708	return (rao);
709}
710
711static void
712call_script(const int argc, const char *const argv[], void *head)
713{
714	const char *scriptpath;
715	int fd[2];
716	int error;
717	pid_t pid, wpid;
718	TAILQ_HEAD(, script_msg) *sm_head;
719
720	if ((scriptpath = argv[0]) == NULL)
721		return;
722
723	fd[0] = fd[1] = -1;
724	sm_head = head;
725	if (sm_head != NULL && !TAILQ_EMPTY(sm_head)) {
726		error = pipe(fd);
727		if (error) {
728			warnmsg(LOG_ERR, __func__,
729			    "failed to create a pipe: %s", strerror(errno));
730			return;
731		}
732	}
733
734	/* launch the script */
735	pid = fork();
736	if (pid < 0) {
737		warnmsg(LOG_ERR, __func__,
738		    "failed to fork: %s", strerror(errno));
739		return;
740	} else if (pid) {	/* parent */
741		int wstatus;
742
743		if (fd[0] != -1) {	/* Send message to the child if any. */
744			ssize_t len;
745			struct script_msg *smp;
746
747			close(fd[0]);
748			TAILQ_FOREACH(smp, sm_head, sm_next) {
749				len = strlen(smp->sm_msg);
750				warnmsg(LOG_DEBUG, __func__,
751				    "write to child = %s(%zd)",
752				    smp->sm_msg, len);
753				if (write(fd[1], smp->sm_msg, len) != len) {
754					warnmsg(LOG_ERR, __func__,
755					    "write to child failed: %s",
756					    strerror(errno));
757					break;
758				}
759			}
760			close(fd[1]);
761		}
762		do {
763			wpid = wait(&wstatus);
764		} while (wpid != pid && wpid > 0);
765
766		if (wpid < 0)
767			warnmsg(LOG_ERR, __func__,
768			    "wait: %s", strerror(errno));
769		else
770			warnmsg(LOG_DEBUG, __func__,
771			    "script \"%s\" terminated", scriptpath);
772	} else {		/* child */
773		int nullfd;
774		char **_argv;
775
776		if (safefile(scriptpath)) {
777			warnmsg(LOG_ERR, __func__,
778			    "script \"%s\" cannot be executed safely",
779			    scriptpath);
780			exit(1);
781		}
782		nullfd = open("/dev/null", O_RDWR);
783		if (nullfd < 0) {
784			warnmsg(LOG_ERR, __func__,
785			    "open /dev/null: %s", strerror(errno));
786			exit(1);
787		}
788		if (fd[0] != -1) {	/* Receive message from STDIN if any. */
789			close(fd[1]);
790			if (fd[0] != STDIN_FILENO) {
791				/* Connect a pipe read-end to child's STDIN. */
792				if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) {
793					warnmsg(LOG_ERR, __func__,
794					    "dup2 STDIN: %s", strerror(errno));
795					exit(1);
796				}
797				close(fd[0]);
798			}
799		} else
800			dup2(nullfd, STDIN_FILENO);
801
802		dup2(nullfd, STDOUT_FILENO);
803		dup2(nullfd, STDERR_FILENO);
804		if (nullfd > STDERR_FILENO)
805			close(nullfd);
806
807		_argv = malloc(sizeof(*_argv) * argc);
808		if (_argv == NULL) {
809			warnmsg(LOG_ERR, __func__,
810				"malloc: %s", strerror(errno));
811			exit(1);
812		}
813		memcpy(_argv, argv, (size_t)argc);
814		execv(scriptpath, (char *const *)_argv);
815		warnmsg(LOG_ERR, __func__, "child: exec failed: %s",
816		    strerror(errno));
817		exit(1);
818	}
819
820	return;
821}
822
823static int
824safefile(const char *path)
825{
826	struct stat s;
827	uid_t myuid;
828
829	/* no setuid */
830	if (getuid() != geteuid()) {
831		warnmsg(LOG_NOTICE, __func__,
832		    "setuid'ed execution not allowed\n");
833		return (-1);
834	}
835
836	if (lstat(path, &s) != 0) {
837		warnmsg(LOG_NOTICE, __func__, "lstat failed: %s",
838		    strerror(errno));
839		return (-1);
840	}
841
842	/* the file must be owned by the running uid */
843	myuid = getuid();
844	if (s.st_uid != myuid) {
845		warnmsg(LOG_NOTICE, __func__,
846		    "%s has invalid owner uid\n", path);
847		return (-1);
848	}
849
850	switch (s.st_mode & S_IFMT) {
851	case S_IFREG:
852		break;
853	default:
854		warnmsg(LOG_NOTICE, __func__,
855		    "%s is an invalid file type 0x%o\n",
856		    path, (s.st_mode & S_IFMT));
857		return (-1);
858	}
859
860	return (0);
861}
862
863/* Decode domain name label encoding in RFC 1035 Section 3.1 */
864static size_t
865dname_labeldec(char *dst, size_t dlen, const char *src)
866{
867	size_t len;
868	const char *src_origin;
869	const char *src_last;
870	const char *dst_origin;
871
872	src_origin = src;
873	src_last = strchr(src, '\0');
874	dst_origin = dst;
875	memset(dst, '\0', dlen);
876	while (src && (len = (uint8_t)(*src++) & 0x3f) &&
877	    (src + len) <= src_last) {
878		if (dst != dst_origin)
879			*dst++ = '.';
880		warnmsg(LOG_DEBUG, __func__, "labellen = %zd", len);
881		memcpy(dst, src, len);
882		src += len;
883		dst += len;
884	}
885	*dst = '\0';
886
887	/*
888	 * XXX validate that domain name only contains valid characters
889	 * for two reasons: 1) correctness, 2) we do not want to pass
890	 * possible malicious, unescaped characters like `` to a script
891	 * or program that could be exploited that way.
892	 */
893
894	return (src - src_origin);
895}
896