usr.sbin/rtsold/rtsol.c

   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
 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
 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
 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
 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 *
 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
 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 *
 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
 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
 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
 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 }