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1 | /* dnsmasq is Copyright (c) 2000-2014 Simon Kelley | |
2 | ||
3 | This program is free software; you can redistribute it and/or modify | |
4 | it under the terms of the GNU General Public License as published by | |
5 | the Free Software Foundation; version 2 dated June, 1991, or | |
6 | (at your option) version 3 dated 29 June, 2007. | |
7 | ||
8 | This program is distributed in the hope that it will be useful, | |
9 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | GNU General Public License for more details. | |
12 | ||
13 | You should have received a copy of the GNU General Public License | |
14 | along with this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | ||
17 | #include "dnsmasq.h" | |
18 | ||
19 | static struct frec *lookup_frec(unsigned short id, void *hash); | |
20 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
21 | union mysockaddr *addr, | |
22 | void *hash); | |
23 | static unsigned short get_id(void); | |
24 | static void free_frec(struct frec *f); | |
25 | static struct randfd *allocate_rfd(int family); | |
26 | ||
27 | #ifdef HAVE_DNSSEC | |
28 | static int tcp_key_recurse(time_t now, int status, struct dns_header *header, size_t n, | |
29 | int class, char *name, char *keyname, struct server *server, int *keycount); | |
30 | static int do_check_sign(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class); | |
31 | static int send_check_sign(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname); | |
32 | #endif | |
33 | ||
34 | ||
35 | /* Send a UDP packet with its source address set as "source" | |
36 | unless nowild is true, when we just send it with the kernel default */ | |
37 | int send_from(int fd, int nowild, char *packet, size_t len, | |
38 | union mysockaddr *to, struct all_addr *source, | |
39 | unsigned int iface) | |
40 | { | |
41 | struct msghdr msg; | |
42 | struct iovec iov[1]; | |
43 | union { | |
44 | struct cmsghdr align; /* this ensures alignment */ | |
45 | #if defined(HAVE_LINUX_NETWORK) | |
46 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
47 | #elif defined(IP_SENDSRCADDR) | |
48 | char control[CMSG_SPACE(sizeof(struct in_addr))]; | |
49 | #endif | |
50 | #ifdef HAVE_IPV6 | |
51 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
52 | #endif | |
53 | } control_u; | |
54 | ||
55 | iov[0].iov_base = packet; | |
56 | iov[0].iov_len = len; | |
57 | ||
58 | msg.msg_control = NULL; | |
59 | msg.msg_controllen = 0; | |
60 | msg.msg_flags = 0; | |
61 | msg.msg_name = to; | |
62 | msg.msg_namelen = sa_len(to); | |
63 | msg.msg_iov = iov; | |
64 | msg.msg_iovlen = 1; | |
65 | ||
66 | if (!nowild) | |
67 | { | |
68 | struct cmsghdr *cmptr; | |
69 | msg.msg_control = &control_u; | |
70 | msg.msg_controllen = sizeof(control_u); | |
71 | cmptr = CMSG_FIRSTHDR(&msg); | |
72 | ||
73 | if (to->sa.sa_family == AF_INET) | |
74 | { | |
75 | #if defined(HAVE_LINUX_NETWORK) | |
76 | struct in_pktinfo p; | |
77 | p.ipi_ifindex = 0; | |
78 | p.ipi_spec_dst = source->addr.addr4; | |
79 | memcpy(CMSG_DATA(cmptr), &p, sizeof(p)); | |
80 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
81 | cmptr->cmsg_level = IPPROTO_IP; | |
82 | cmptr->cmsg_type = IP_PKTINFO; | |
83 | #elif defined(IP_SENDSRCADDR) | |
84 | memcpy(CMSG_DATA(cmptr), &(source->addr.addr4), sizeof(source->addr.addr4)); | |
85 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); | |
86 | cmptr->cmsg_level = IPPROTO_IP; | |
87 | cmptr->cmsg_type = IP_SENDSRCADDR; | |
88 | #endif | |
89 | } | |
90 | else | |
91 | #ifdef HAVE_IPV6 | |
92 | { | |
93 | struct in6_pktinfo p; | |
94 | p.ipi6_ifindex = iface; /* Need iface for IPv6 to handle link-local addrs */ | |
95 | p.ipi6_addr = source->addr.addr6; | |
96 | memcpy(CMSG_DATA(cmptr), &p, sizeof(p)); | |
97 | msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); | |
98 | cmptr->cmsg_type = daemon->v6pktinfo; | |
99 | cmptr->cmsg_level = IPPROTO_IPV6; | |
100 | } | |
101 | #else | |
102 | (void)iface; /* eliminate warning */ | |
103 | #endif | |
104 | } | |
105 | ||
106 | while (sendmsg(fd, &msg, 0) == -1) | |
107 | { | |
108 | if (retry_send()) | |
109 | continue; | |
110 | ||
111 | /* If interface is still in DAD, EINVAL results - ignore that. */ | |
112 | if (errno == EINVAL) | |
113 | break; | |
114 | ||
115 | my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno)); | |
116 | return 0; | |
117 | } | |
118 | ||
119 | return 1; | |
120 | } | |
121 | ||
122 | static unsigned int search_servers(time_t now, struct all_addr **addrpp, | |
123 | unsigned int qtype, char *qdomain, int *type, char **domain, int *norebind) | |
124 | ||
125 | { | |
126 | /* If the query ends in the domain in one of our servers, set | |
127 | domain to point to that name. We find the largest match to allow both | |
128 | domain.org and sub.domain.org to exist. */ | |
129 | ||
130 | unsigned int namelen = strlen(qdomain); | |
131 | unsigned int matchlen = 0; | |
132 | struct server *serv; | |
133 | unsigned int flags = 0; | |
134 | ||
135 | for (serv = daemon->servers; serv; serv=serv->next) | |
136 | /* domain matches take priority over NODOTS matches */ | |
137 | if ((serv->flags & SERV_FOR_NODOTS) && *type != SERV_HAS_DOMAIN && !strchr(qdomain, '.') && namelen != 0) | |
138 | { | |
139 | unsigned int sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
140 | *type = SERV_FOR_NODOTS; | |
141 | if (serv->flags & SERV_NO_ADDR) | |
142 | flags = F_NXDOMAIN; | |
143 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
144 | { | |
145 | if (sflag & qtype) | |
146 | { | |
147 | flags = sflag; | |
148 | if (serv->addr.sa.sa_family == AF_INET) | |
149 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
150 | #ifdef HAVE_IPV6 | |
151 | else | |
152 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
153 | #endif | |
154 | } | |
155 | else if (!flags || (flags & F_NXDOMAIN)) | |
156 | flags = F_NOERR; | |
157 | } | |
158 | } | |
159 | else if (serv->flags & SERV_HAS_DOMAIN) | |
160 | { | |
161 | unsigned int domainlen = strlen(serv->domain); | |
162 | char *matchstart = qdomain + namelen - domainlen; | |
163 | if (namelen >= domainlen && | |
164 | hostname_isequal(matchstart, serv->domain) && | |
165 | (domainlen == 0 || namelen == domainlen || *(matchstart-1) == '.' )) | |
166 | { | |
167 | if (serv->flags & SERV_NO_REBIND) | |
168 | *norebind = 1; | |
169 | else | |
170 | { | |
171 | unsigned int sflag = serv->addr.sa.sa_family == AF_INET ? F_IPV4 : F_IPV6; | |
172 | /* implement priority rules for --address and --server for same domain. | |
173 | --address wins if the address is for the correct AF | |
174 | --server wins otherwise. */ | |
175 | if (domainlen != 0 && domainlen == matchlen) | |
176 | { | |
177 | if ((serv->flags & SERV_LITERAL_ADDRESS)) | |
178 | { | |
179 | if (!(sflag & qtype) && flags == 0) | |
180 | continue; | |
181 | } | |
182 | else | |
183 | { | |
184 | if (flags & (F_IPV4 | F_IPV6)) | |
185 | continue; | |
186 | } | |
187 | } | |
188 | ||
189 | if (domainlen >= matchlen) | |
190 | { | |
191 | *type = serv->flags & (SERV_HAS_DOMAIN | SERV_USE_RESOLV | SERV_NO_REBIND); | |
192 | *domain = serv->domain; | |
193 | matchlen = domainlen; | |
194 | if (serv->flags & SERV_NO_ADDR) | |
195 | flags = F_NXDOMAIN; | |
196 | else if (serv->flags & SERV_LITERAL_ADDRESS) | |
197 | { | |
198 | if (sflag & qtype) | |
199 | { | |
200 | flags = sflag; | |
201 | if (serv->addr.sa.sa_family == AF_INET) | |
202 | *addrpp = (struct all_addr *)&serv->addr.in.sin_addr; | |
203 | #ifdef HAVE_IPV6 | |
204 | else | |
205 | *addrpp = (struct all_addr *)&serv->addr.in6.sin6_addr; | |
206 | #endif | |
207 | } | |
208 | else if (!flags || (flags & F_NXDOMAIN)) | |
209 | flags = F_NOERR; | |
210 | } | |
211 | else | |
212 | flags = 0; | |
213 | } | |
214 | } | |
215 | } | |
216 | } | |
217 | ||
218 | if (flags == 0 && !(qtype & F_QUERY) && | |
219 | option_bool(OPT_NODOTS_LOCAL) && !strchr(qdomain, '.') && namelen != 0) | |
220 | /* don't forward A or AAAA queries for simple names, except the empty name */ | |
221 | flags = F_NOERR; | |
222 | ||
223 | if (flags == F_NXDOMAIN && check_for_local_domain(qdomain, now)) | |
224 | flags = F_NOERR; | |
225 | ||
226 | if (flags) | |
227 | { | |
228 | int logflags = 0; | |
229 | ||
230 | if (flags == F_NXDOMAIN || flags == F_NOERR) | |
231 | logflags = F_NEG | qtype; | |
232 | ||
233 | log_query(logflags | flags | F_CONFIG | F_FORWARD, qdomain, *addrpp, NULL); | |
234 | } | |
235 | else if ((*type) & SERV_USE_RESOLV) | |
236 | { | |
237 | *type = 0; /* use normal servers for this domain */ | |
238 | *domain = NULL; | |
239 | } | |
240 | return flags; | |
241 | } | |
242 | ||
243 | static int forward_query(int udpfd, union mysockaddr *udpaddr, | |
244 | struct all_addr *dst_addr, unsigned int dst_iface, | |
245 | struct dns_header *header, size_t plen, time_t now, | |
246 | struct frec *forward, int ad_reqd, int do_bit) | |
247 | { | |
248 | char *domain = NULL; | |
249 | int type = 0, norebind = 0; | |
250 | struct all_addr *addrp = NULL; | |
251 | unsigned int flags = 0; | |
252 | struct server *start = NULL; | |
253 | #ifdef HAVE_DNSSEC | |
254 | void *hash = hash_questions(header, plen, daemon->namebuff); | |
255 | #else | |
256 | unsigned int crc = questions_crc(header, plen, daemon->namebuff); | |
257 | void *hash = &crc; | |
258 | #endif | |
259 | unsigned int gotname = extract_request(header, plen, daemon->namebuff, NULL); | |
260 | ||
261 | (void)do_bit; | |
262 | ||
263 | /* may be no servers available. */ | |
264 | if (!daemon->servers) | |
265 | forward = NULL; | |
266 | else if (forward || (hash && (forward = lookup_frec_by_sender(ntohs(header->id), udpaddr, hash)))) | |
267 | { | |
268 | #ifdef HAVE_DNSSEC | |
269 | /* If we've already got an answer to this query, but we're awaiting keys for validation, | |
270 | there's no point retrying the query, retry the key query instead...... */ | |
271 | if (forward->blocking_query) | |
272 | { | |
273 | int fd; | |
274 | ||
275 | while (forward->blocking_query) | |
276 | forward = forward->blocking_query; | |
277 | ||
278 | blockdata_retrieve(forward->stash, forward->stash_len, (void *)header); | |
279 | plen = forward->stash_len; | |
280 | ||
281 | if (forward->sentto->addr.sa.sa_family == AF_INET) | |
282 | log_query(F_DNSSEC | F_IPV4, "retry", (struct all_addr *)&forward->sentto->addr.in.sin_addr, "dnssec"); | |
283 | #ifdef HAVE_IPV6 | |
284 | else | |
285 | log_query(F_DNSSEC | F_IPV6, "retry", (struct all_addr *)&forward->sentto->addr.in6.sin6_addr, "dnssec"); | |
286 | #endif | |
287 | ||
288 | if (forward->sentto->sfd) | |
289 | fd = forward->sentto->sfd->fd; | |
290 | else | |
291 | { | |
292 | #ifdef HAVE_IPV6 | |
293 | if (forward->sentto->addr.sa.sa_family == AF_INET6) | |
294 | fd = forward->rfd6->fd; | |
295 | else | |
296 | #endif | |
297 | fd = forward->rfd4->fd; | |
298 | } | |
299 | ||
300 | while (sendto(fd, (char *)header, plen, 0, | |
301 | &forward->sentto->addr.sa, | |
302 | sa_len(&forward->sentto->addr)) == -1 && retry_send()); | |
303 | ||
304 | return 1; | |
305 | } | |
306 | #endif | |
307 | ||
308 | /* retry on existing query, send to all available servers */ | |
309 | domain = forward->sentto->domain; | |
310 | forward->sentto->failed_queries++; | |
311 | if (!option_bool(OPT_ORDER)) | |
312 | { | |
313 | forward->forwardall = 1; | |
314 | daemon->last_server = NULL; | |
315 | } | |
316 | type = forward->sentto->flags & SERV_TYPE; | |
317 | if (!(start = forward->sentto->next)) | |
318 | start = daemon->servers; /* at end of list, recycle */ | |
319 | header->id = htons(forward->new_id); | |
320 | } | |
321 | else | |
322 | { | |
323 | if (gotname) | |
324 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind); | |
325 | ||
326 | if (!flags && !(forward = get_new_frec(now, NULL, 0))) | |
327 | /* table full - server failure. */ | |
328 | flags = F_NEG; | |
329 | ||
330 | if (forward) | |
331 | { | |
332 | forward->source = *udpaddr; | |
333 | forward->dest = *dst_addr; | |
334 | forward->iface = dst_iface; | |
335 | forward->orig_id = ntohs(header->id); | |
336 | forward->new_id = get_id(); | |
337 | forward->fd = udpfd; | |
338 | memcpy(forward->hash, hash, HASH_SIZE); | |
339 | forward->forwardall = 0; | |
340 | forward->flags = 0; | |
341 | if (norebind) | |
342 | forward->flags |= FREC_NOREBIND; | |
343 | if (header->hb4 & HB4_CD) | |
344 | forward->flags |= FREC_CHECKING_DISABLED; | |
345 | if (ad_reqd) | |
346 | forward->flags |= FREC_AD_QUESTION; | |
347 | #ifdef HAVE_DNSSEC | |
348 | forward->work_counter = DNSSEC_WORK; | |
349 | if (do_bit) | |
350 | forward->flags |= FREC_DO_QUESTION; | |
351 | #endif | |
352 | ||
353 | header->id = htons(forward->new_id); | |
354 | ||
355 | /* In strict_order mode, always try servers in the order | |
356 | specified in resolv.conf, if a domain is given | |
357 | always try all the available servers, | |
358 | otherwise, use the one last known to work. */ | |
359 | ||
360 | if (type == 0) | |
361 | { | |
362 | if (option_bool(OPT_ORDER)) | |
363 | start = daemon->servers; | |
364 | else if (!(start = daemon->last_server) || | |
365 | daemon->forwardcount++ > FORWARD_TEST || | |
366 | difftime(now, daemon->forwardtime) > FORWARD_TIME) | |
367 | { | |
368 | start = daemon->servers; | |
369 | forward->forwardall = 1; | |
370 | daemon->forwardcount = 0; | |
371 | daemon->forwardtime = now; | |
372 | } | |
373 | } | |
374 | else | |
375 | { | |
376 | start = daemon->servers; | |
377 | if (!option_bool(OPT_ORDER)) | |
378 | forward->forwardall = 1; | |
379 | } | |
380 | } | |
381 | } | |
382 | ||
383 | /* check for send errors here (no route to host) | |
384 | if we fail to send to all nameservers, send back an error | |
385 | packet straight away (helps modem users when offline) */ | |
386 | ||
387 | if (!flags && forward) | |
388 | { | |
389 | struct server *firstsentto = start; | |
390 | int forwarded = 0; | |
391 | ||
392 | if (option_bool(OPT_ADD_MAC)) | |
393 | plen = add_mac(header, plen, ((char *) header) + daemon->packet_buff_sz, &forward->source); | |
394 | ||
395 | if (option_bool(OPT_CLIENT_SUBNET)) | |
396 | { | |
397 | size_t new = add_source_addr(header, plen, ((char *) header) + daemon->packet_buff_sz, &forward->source); | |
398 | if (new != plen) | |
399 | { | |
400 | plen = new; | |
401 | forward->flags |= FREC_HAS_SUBNET; | |
402 | } | |
403 | } | |
404 | ||
405 | #ifdef HAVE_DNSSEC | |
406 | if (option_bool(OPT_DNSSEC_VALID)) | |
407 | { | |
408 | size_t new_plen = add_do_bit(header, plen, ((char *) header) + daemon->packet_buff_sz); | |
409 | ||
410 | /* For debugging, set Checking Disabled, otherwise, have the upstream check too, | |
411 | this allows it to select auth servers when one is returning bad data. */ | |
412 | if (option_bool(OPT_DNSSEC_DEBUG)) | |
413 | header->hb4 |= HB4_CD; | |
414 | ||
415 | if (new_plen != plen) | |
416 | forward->flags |= FREC_ADDED_PHEADER; | |
417 | ||
418 | plen = new_plen; | |
419 | } | |
420 | #endif | |
421 | ||
422 | while (1) | |
423 | { | |
424 | /* only send to servers dealing with our domain. | |
425 | domain may be NULL, in which case server->domain | |
426 | must be NULL also. */ | |
427 | ||
428 | if (type == (start->flags & SERV_TYPE) && | |
429 | (type != SERV_HAS_DOMAIN || hostname_isequal(domain, start->domain)) && | |
430 | !(start->flags & SERV_LITERAL_ADDRESS)) | |
431 | { | |
432 | int fd; | |
433 | ||
434 | /* find server socket to use, may need to get random one. */ | |
435 | if (start->sfd) | |
436 | fd = start->sfd->fd; | |
437 | else | |
438 | { | |
439 | #ifdef HAVE_IPV6 | |
440 | if (start->addr.sa.sa_family == AF_INET6) | |
441 | { | |
442 | if (!forward->rfd6 && | |
443 | !(forward->rfd6 = allocate_rfd(AF_INET6))) | |
444 | break; | |
445 | daemon->rfd_save = forward->rfd6; | |
446 | fd = forward->rfd6->fd; | |
447 | } | |
448 | else | |
449 | #endif | |
450 | { | |
451 | if (!forward->rfd4 && | |
452 | !(forward->rfd4 = allocate_rfd(AF_INET))) | |
453 | break; | |
454 | daemon->rfd_save = forward->rfd4; | |
455 | fd = forward->rfd4->fd; | |
456 | } | |
457 | ||
458 | #ifdef HAVE_CONNTRACK | |
459 | /* Copy connection mark of incoming query to outgoing connection. */ | |
460 | if (option_bool(OPT_CONNTRACK)) | |
461 | { | |
462 | unsigned int mark; | |
463 | if (get_incoming_mark(&forward->source, &forward->dest, 0, &mark)) | |
464 | setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int)); | |
465 | } | |
466 | #endif | |
467 | } | |
468 | ||
469 | if (sendto(fd, (char *)header, plen, 0, | |
470 | &start->addr.sa, | |
471 | sa_len(&start->addr)) == -1) | |
472 | { | |
473 | if (retry_send()) | |
474 | continue; | |
475 | } | |
476 | else | |
477 | { | |
478 | /* Keep info in case we want to re-send this packet */ | |
479 | daemon->srv_save = start; | |
480 | daemon->packet_len = plen; | |
481 | ||
482 | if (!gotname) | |
483 | strcpy(daemon->namebuff, "query"); | |
484 | if (start->addr.sa.sa_family == AF_INET) | |
485 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, | |
486 | (struct all_addr *)&start->addr.in.sin_addr, NULL); | |
487 | #ifdef HAVE_IPV6 | |
488 | else | |
489 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, | |
490 | (struct all_addr *)&start->addr.in6.sin6_addr, NULL); | |
491 | #endif | |
492 | start->queries++; | |
493 | forwarded = 1; | |
494 | forward->sentto = start; | |
495 | if (!forward->forwardall) | |
496 | break; | |
497 | forward->forwardall++; | |
498 | } | |
499 | } | |
500 | ||
501 | if (!(start = start->next)) | |
502 | start = daemon->servers; | |
503 | ||
504 | if (start == firstsentto) | |
505 | break; | |
506 | } | |
507 | ||
508 | if (forwarded) | |
509 | return 1; | |
510 | ||
511 | /* could not send on, prepare to return */ | |
512 | header->id = htons(forward->orig_id); | |
513 | free_frec(forward); /* cancel */ | |
514 | } | |
515 | ||
516 | /* could not send on, return empty answer or address if known for whole domain */ | |
517 | if (udpfd != -1) | |
518 | { | |
519 | plen = setup_reply(header, plen, addrp, flags, daemon->local_ttl); | |
520 | send_from(udpfd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), (char *)header, plen, udpaddr, dst_addr, dst_iface); | |
521 | } | |
522 | ||
523 | return 0; | |
524 | } | |
525 | ||
526 | static size_t process_reply(struct dns_header *header, time_t now, struct server *server, size_t n, int check_rebind, | |
527 | int no_cache, int cache_secure, int ad_reqd, int do_bit, int added_pheader, int check_subnet, union mysockaddr *query_source) | |
528 | { | |
529 | unsigned char *pheader, *sizep; | |
530 | char **sets = 0; | |
531 | int munged = 0, is_sign; | |
532 | size_t plen; | |
533 | ||
534 | (void)ad_reqd; | |
535 | (void) do_bit; | |
536 | ||
537 | #ifdef HAVE_IPSET | |
538 | if (daemon->ipsets && extract_request(header, n, daemon->namebuff, NULL)) | |
539 | { | |
540 | /* Similar algorithm to search_servers. */ | |
541 | struct ipsets *ipset_pos; | |
542 | unsigned int namelen = strlen(daemon->namebuff); | |
543 | unsigned int matchlen = 0; | |
544 | for (ipset_pos = daemon->ipsets; ipset_pos; ipset_pos = ipset_pos->next) | |
545 | { | |
546 | unsigned int domainlen = strlen(ipset_pos->domain); | |
547 | char *matchstart = daemon->namebuff + namelen - domainlen; | |
548 | if (namelen >= domainlen && hostname_isequal(matchstart, ipset_pos->domain) && | |
549 | (domainlen == 0 || namelen == domainlen || *(matchstart - 1) == '.' ) && | |
550 | domainlen >= matchlen) | |
551 | { | |
552 | matchlen = domainlen; | |
553 | sets = ipset_pos->sets; | |
554 | } | |
555 | } | |
556 | } | |
557 | #endif | |
558 | ||
559 | /* If upstream is advertising a larger UDP packet size | |
560 | than we allow, trim it so that we don't get overlarge | |
561 | requests for the client. We can't do this for signed packets. */ | |
562 | ||
563 | if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign))) | |
564 | { | |
565 | unsigned short udpsz; | |
566 | unsigned char *psave = sizep; | |
567 | ||
568 | GETSHORT(udpsz, sizep); | |
569 | ||
570 | if (!is_sign && udpsz > daemon->edns_pktsz) | |
571 | PUTSHORT(daemon->edns_pktsz, psave); | |
572 | ||
573 | if (check_subnet && !check_source(header, plen, pheader, query_source)) | |
574 | { | |
575 | my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch")); | |
576 | return 0; | |
577 | } | |
578 | ||
579 | if (added_pheader) | |
580 | { | |
581 | pheader = 0; | |
582 | header->arcount = htons(0); | |
583 | } | |
584 | } | |
585 | ||
586 | /* RFC 4035 sect 4.6 para 3 */ | |
587 | if (!is_sign && !option_bool(OPT_DNSSEC_PROXY)) | |
588 | header->hb4 &= ~HB4_AD; | |
589 | ||
590 | if (OPCODE(header) != QUERY || (RCODE(header) != NOERROR && RCODE(header) != NXDOMAIN)) | |
591 | return n; | |
592 | ||
593 | /* Complain loudly if the upstream server is non-recursive. */ | |
594 | if (!(header->hb4 & HB4_RA) && RCODE(header) == NOERROR && ntohs(header->ancount) == 0 && | |
595 | server && !(server->flags & SERV_WARNED_RECURSIVE)) | |
596 | { | |
597 | prettyprint_addr(&server->addr, daemon->namebuff); | |
598 | my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff); | |
599 | if (!option_bool(OPT_LOG)) | |
600 | server->flags |= SERV_WARNED_RECURSIVE; | |
601 | } | |
602 | ||
603 | if (daemon->bogus_addr && RCODE(header) != NXDOMAIN && | |
604 | check_for_bogus_wildcard(header, n, daemon->namebuff, daemon->bogus_addr, now)) | |
605 | { | |
606 | munged = 1; | |
607 | SET_RCODE(header, NXDOMAIN); | |
608 | header->hb3 &= ~HB3_AA; | |
609 | cache_secure = 0; | |
610 | } | |
611 | else | |
612 | { | |
613 | int doctored = 0; | |
614 | ||
615 | if (RCODE(header) == NXDOMAIN && | |
616 | extract_request(header, n, daemon->namebuff, NULL) && | |
617 | check_for_local_domain(daemon->namebuff, now)) | |
618 | { | |
619 | /* if we forwarded a query for a locally known name (because it was for | |
620 | an unknown type) and the answer is NXDOMAIN, convert that to NODATA, | |
621 | since we know that the domain exists, even if upstream doesn't */ | |
622 | munged = 1; | |
623 | header->hb3 |= HB3_AA; | |
624 | SET_RCODE(header, NOERROR); | |
625 | cache_secure = 0; | |
626 | } | |
627 | ||
628 | if (extract_addresses(header, n, daemon->namebuff, now, sets, is_sign, check_rebind, no_cache, cache_secure, &doctored)) | |
629 | { | |
630 | my_syslog(LOG_WARNING, _("possible DNS-rebind attack detected: %s"), daemon->namebuff); | |
631 | munged = 1; | |
632 | cache_secure = 0; | |
633 | } | |
634 | ||
635 | if (doctored) | |
636 | cache_secure = 0; | |
637 | } | |
638 | ||
639 | #ifdef HAVE_DNSSEC | |
640 | if (no_cache && !(header->hb4 & HB4_CD)) | |
641 | { | |
642 | if (!option_bool(OPT_DNSSEC_DEBUG)) | |
643 | { | |
644 | /* Bogus reply, turn into SERVFAIL */ | |
645 | SET_RCODE(header, SERVFAIL); | |
646 | munged = 1; | |
647 | } | |
648 | } | |
649 | ||
650 | if (option_bool(OPT_DNSSEC_VALID)) | |
651 | header->hb4 &= ~HB4_AD; | |
652 | ||
653 | if (!(header->hb4 & HB4_CD) && ad_reqd && cache_secure) | |
654 | header->hb4 |= HB4_AD; | |
655 | ||
656 | /* If the requestor didn't set the DO bit, don't return DNSSEC info. */ | |
657 | if (!do_bit) | |
658 | n = filter_rrsigs(header, n); | |
659 | #endif | |
660 | ||
661 | /* do this after extract_addresses. Ensure NODATA reply and remove | |
662 | nameserver info. */ | |
663 | ||
664 | if (munged) | |
665 | { | |
666 | header->ancount = htons(0); | |
667 | header->nscount = htons(0); | |
668 | header->arcount = htons(0); | |
669 | } | |
670 | ||
671 | /* the bogus-nxdomain stuff, doctor and NXDOMAIN->NODATA munging can all elide | |
672 | sections of the packet. Find the new length here and put back pseudoheader | |
673 | if it was removed. */ | |
674 | return resize_packet(header, n, pheader, plen); | |
675 | } | |
676 | ||
677 | /* sets new last_server */ | |
678 | void reply_query(int fd, int family, time_t now) | |
679 | { | |
680 | /* packet from peer server, extract data for cache, and send to | |
681 | original requester */ | |
682 | struct dns_header *header; | |
683 | union mysockaddr serveraddr; | |
684 | struct frec *forward; | |
685 | socklen_t addrlen = sizeof(serveraddr); | |
686 | ssize_t n = recvfrom(fd, daemon->packet, daemon->packet_buff_sz, 0, &serveraddr.sa, &addrlen); | |
687 | size_t nn; | |
688 | struct server *server; | |
689 | void *hash; | |
690 | #ifndef HAVE_DNSSEC | |
691 | unsigned int crc; | |
692 | #endif | |
693 | ||
694 | /* packet buffer overwritten */ | |
695 | daemon->srv_save = NULL; | |
696 | ||
697 | /* Determine the address of the server replying so that we can mark that as good */ | |
698 | serveraddr.sa.sa_family = family; | |
699 | #ifdef HAVE_IPV6 | |
700 | if (serveraddr.sa.sa_family == AF_INET6) | |
701 | serveraddr.in6.sin6_flowinfo = 0; | |
702 | #endif | |
703 | ||
704 | header = (struct dns_header *)daemon->packet; | |
705 | ||
706 | if (n < (int)sizeof(struct dns_header) || !(header->hb3 & HB3_QR)) | |
707 | return; | |
708 | ||
709 | /* spoof check: answer must come from known server, */ | |
710 | for (server = daemon->servers; server; server = server->next) | |
711 | if (!(server->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR)) && | |
712 | sockaddr_isequal(&server->addr, &serveraddr)) | |
713 | break; | |
714 | ||
715 | if (!server) | |
716 | return; | |
717 | ||
718 | #ifdef HAVE_DNSSEC | |
719 | hash = hash_questions(header, n, daemon->namebuff); | |
720 | #else | |
721 | hash = &crc; | |
722 | crc = questions_crc(header, n, daemon->namebuff); | |
723 | #endif | |
724 | ||
725 | if (!(forward = lookup_frec(ntohs(header->id), hash))) | |
726 | return; | |
727 | ||
728 | if ((RCODE(header) == SERVFAIL || RCODE(header) == REFUSED) && | |
729 | !option_bool(OPT_ORDER) && | |
730 | forward->forwardall == 0) | |
731 | /* for broken servers, attempt to send to another one. */ | |
732 | { | |
733 | unsigned char *pheader; | |
734 | size_t plen; | |
735 | int is_sign; | |
736 | ||
737 | /* recreate query from reply */ | |
738 | pheader = find_pseudoheader(header, (size_t)n, &plen, NULL, &is_sign); | |
739 | if (!is_sign) | |
740 | { | |
741 | header->ancount = htons(0); | |
742 | header->nscount = htons(0); | |
743 | header->arcount = htons(0); | |
744 | if ((nn = resize_packet(header, (size_t)n, pheader, plen))) | |
745 | { | |
746 | header->hb3 &= ~(HB3_QR | HB3_TC); | |
747 | forward_query(-1, NULL, NULL, 0, header, nn, now, forward, 0, 0); | |
748 | return; | |
749 | } | |
750 | } | |
751 | } | |
752 | ||
753 | server = forward->sentto; | |
754 | ||
755 | if ((forward->sentto->flags & SERV_TYPE) == 0) | |
756 | { | |
757 | if (RCODE(header) == REFUSED) | |
758 | server = NULL; | |
759 | else | |
760 | { | |
761 | struct server *last_server; | |
762 | ||
763 | /* find good server by address if possible, otherwise assume the last one we sent to */ | |
764 | for (last_server = daemon->servers; last_server; last_server = last_server->next) | |
765 | if (!(last_server->flags & (SERV_LITERAL_ADDRESS | SERV_HAS_DOMAIN | SERV_FOR_NODOTS | SERV_NO_ADDR)) && | |
766 | sockaddr_isequal(&last_server->addr, &serveraddr)) | |
767 | { | |
768 | server = last_server; | |
769 | break; | |
770 | } | |
771 | } | |
772 | if (!option_bool(OPT_ALL_SERVERS)) | |
773 | daemon->last_server = server; | |
774 | } | |
775 | ||
776 | /* If the answer is an error, keep the forward record in place in case | |
777 | we get a good reply from another server. Kill it when we've | |
778 | had replies from all to avoid filling the forwarding table when | |
779 | everything is broken */ | |
780 | if (forward->forwardall == 0 || --forward->forwardall == 1 || RCODE(header) != SERVFAIL) | |
781 | { | |
782 | int check_rebind = 0, no_cache_dnssec = 0, cache_secure = 0; | |
783 | ||
784 | if (option_bool(OPT_NO_REBIND)) | |
785 | check_rebind = !(forward->flags & FREC_NOREBIND); | |
786 | ||
787 | /* Don't cache replies where DNSSEC validation was turned off, either | |
788 | the upstream server told us so, or the original query specified it. */ | |
789 | if ((header->hb4 & HB4_CD) || (forward->flags & FREC_CHECKING_DISABLED)) | |
790 | no_cache_dnssec = 1; | |
791 | ||
792 | #ifdef HAVE_DNSSEC | |
793 | if (server && option_bool(OPT_DNSSEC_VALID) && !(forward->flags & FREC_CHECKING_DISABLED)) | |
794 | { | |
795 | int status; | |
796 | ||
797 | /* We've had a reply already, which we're validating. Ignore this duplicate */ | |
798 | if (forward->blocking_query) | |
799 | return; | |
800 | ||
801 | if (header->hb3 & HB3_TC) | |
802 | { | |
803 | /* Truncated answer can't be validated. | |
804 | If this is an answer to a DNSSEC-generated query, we still | |
805 | need to get the client to retry over TCP, so return | |
806 | an answer with the TC bit set, even if the actual answer fits. | |
807 | */ | |
808 | status = STAT_TRUNCATED; | |
809 | } | |
810 | else if (forward->flags & FREC_DNSKEY_QUERY) | |
811 | status = dnssec_validate_by_ds(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
812 | else if (forward->flags & FREC_DS_QUERY) | |
813 | { | |
814 | status = dnssec_validate_ds(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
815 | if (status == STAT_NO_DS) | |
816 | status = STAT_INSECURE; | |
817 | } | |
818 | else if (forward->flags & FREC_CHECK_NOSIGN) | |
819 | status = do_check_sign(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
820 | else | |
821 | { | |
822 | status = dnssec_validate_reply(now, header, n, daemon->namebuff, daemon->keyname, &forward->class, NULL); | |
823 | if (status == STAT_NO_SIG) | |
824 | { | |
825 | if (option_bool(OPT_DNSSEC_NO_SIGN)) | |
826 | status = send_check_sign(now, header, n, daemon->namebuff, daemon->keyname); | |
827 | else | |
828 | status = STAT_INSECURE; | |
829 | } | |
830 | } | |
831 | /* Can't validate, as we're missing key data. Put this | |
832 | answer aside, whilst we get that. */ | |
833 | if (status == STAT_NEED_DS || status == STAT_NEED_DS_NEG || status == STAT_NEED_KEY) | |
834 | { | |
835 | struct frec *new, *orig; | |
836 | ||
837 | /* Free any saved query */ | |
838 | if (forward->stash) | |
839 | blockdata_free(forward->stash); | |
840 | ||
841 | /* Now save reply pending receipt of key data */ | |
842 | if (!(forward->stash = blockdata_alloc((char *)header, n))) | |
843 | return; | |
844 | forward->stash_len = n; | |
845 | ||
846 | anotherkey: | |
847 | /* Find the original query that started it all.... */ | |
848 | for (orig = forward; orig->dependent; orig = orig->dependent); | |
849 | ||
850 | if (--orig->work_counter == 0 || !(new = get_new_frec(now, NULL, 1))) | |
851 | status = STAT_INSECURE; | |
852 | else | |
853 | { | |
854 | int fd; | |
855 | struct frec *next = new->next; | |
856 | *new = *forward; /* copy everything, then overwrite */ | |
857 | new->next = next; | |
858 | new->blocking_query = NULL; | |
859 | new->sentto = server; | |
860 | new->rfd4 = NULL; | |
861 | #ifdef HAVE_IPV6 | |
862 | new->rfd6 = NULL; | |
863 | #endif | |
864 | new->flags &= ~(FREC_DNSKEY_QUERY | FREC_DS_QUERY | FREC_CHECK_NOSIGN); | |
865 | ||
866 | new->dependent = forward; /* to find query awaiting new one. */ | |
867 | forward->blocking_query = new; /* for garbage cleaning */ | |
868 | /* validate routines leave name of required record in daemon->keyname */ | |
869 | if (status == STAT_NEED_KEY) | |
870 | { | |
871 | new->flags |= FREC_DNSKEY_QUERY; | |
872 | nn = dnssec_generate_query(header, ((char *) header) + daemon->packet_buff_sz, | |
873 | daemon->keyname, forward->class, T_DNSKEY, &server->addr); | |
874 | } | |
875 | else | |
876 | { | |
877 | if (status == STAT_NEED_DS_NEG) | |
878 | new->flags |= FREC_CHECK_NOSIGN; | |
879 | else | |
880 | new->flags |= FREC_DS_QUERY; | |
881 | nn = dnssec_generate_query(header,((char *) header) + daemon->packet_buff_sz, | |
882 | daemon->keyname, forward->class, T_DS, &server->addr); | |
883 | } | |
884 | if ((hash = hash_questions(header, nn, daemon->namebuff))) | |
885 | memcpy(new->hash, hash, HASH_SIZE); | |
886 | new->new_id = get_id(); | |
887 | header->id = htons(new->new_id); | |
888 | /* Save query for retransmission */ | |
889 | new->stash = blockdata_alloc((char *)header, nn); | |
890 | new->stash_len = nn; | |
891 | ||
892 | /* Don't resend this. */ | |
893 | daemon->srv_save = NULL; | |
894 | ||
895 | if (server->sfd) | |
896 | fd = server->sfd->fd; | |
897 | else | |
898 | { | |
899 | fd = -1; | |
900 | #ifdef HAVE_IPV6 | |
901 | if (server->addr.sa.sa_family == AF_INET6) | |
902 | { | |
903 | if (new->rfd6 || (new->rfd6 = allocate_rfd(AF_INET6))) | |
904 | fd = new->rfd6->fd; | |
905 | } | |
906 | else | |
907 | #endif | |
908 | { | |
909 | if (new->rfd4 || (new->rfd4 = allocate_rfd(AF_INET))) | |
910 | fd = new->rfd4->fd; | |
911 | } | |
912 | } | |
913 | ||
914 | if (fd != -1) | |
915 | { | |
916 | while (sendto(fd, (char *)header, nn, 0, &server->addr.sa, sa_len(&server->addr)) == -1 && retry_send()); | |
917 | server->queries++; | |
918 | } | |
919 | ||
920 | return; | |
921 | } | |
922 | } | |
923 | ||
924 | /* Ok, we reached far enough up the chain-of-trust that we can validate something. | |
925 | Now wind back down, pulling back answers which wouldn't previously validate | |
926 | and validate them with the new data. Note that if an answer needs multiple | |
927 | keys to validate, we may find another key is needed, in which case we set off | |
928 | down another branch of the tree. Once we get to the original answer | |
929 | (FREC_DNSSEC_QUERY not set) and it validates, return it to the original requestor. */ | |
930 | while (forward->dependent) | |
931 | { | |
932 | struct frec *prev = forward->dependent; | |
933 | free_frec(forward); | |
934 | forward = prev; | |
935 | forward->blocking_query = NULL; /* already gone */ | |
936 | blockdata_retrieve(forward->stash, forward->stash_len, (void *)header); | |
937 | n = forward->stash_len; | |
938 | ||
939 | if (status == STAT_SECURE) | |
940 | { | |
941 | if (forward->flags & FREC_DNSKEY_QUERY) | |
942 | status = dnssec_validate_by_ds(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
943 | else if (forward->flags & FREC_DS_QUERY) | |
944 | { | |
945 | status = dnssec_validate_ds(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
946 | if (status == STAT_NO_DS) | |
947 | status = STAT_INSECURE; | |
948 | } | |
949 | else if (forward->flags & FREC_CHECK_NOSIGN) | |
950 | status = do_check_sign(now, header, n, daemon->namebuff, daemon->keyname, forward->class); | |
951 | else | |
952 | { | |
953 | status = dnssec_validate_reply(now, header, n, daemon->namebuff, daemon->keyname, &forward->class, NULL); | |
954 | if (status == STAT_NO_SIG) | |
955 | { | |
956 | if (option_bool(OPT_DNSSEC_NO_SIGN)) | |
957 | status = send_check_sign(now, header, n, daemon->namebuff, daemon->keyname); | |
958 | else | |
959 | status = STAT_INSECURE; | |
960 | } | |
961 | } | |
962 | ||
963 | if (status == STAT_NEED_DS || status == STAT_NEED_DS_NEG || status == STAT_NEED_KEY) | |
964 | goto anotherkey; | |
965 | } | |
966 | } | |
967 | ||
968 | if (status == STAT_TRUNCATED) | |
969 | header->hb3 |= HB3_TC; | |
970 | else | |
971 | { | |
972 | char *result; | |
973 | ||
974 | if (forward->work_counter == 0) | |
975 | result = "ABANDONED"; | |
976 | else | |
977 | result = (status == STAT_SECURE ? "SECURE" : (status == STAT_INSECURE ? "INSECURE" : "BOGUS")); | |
978 | ||
979 | log_query(F_KEYTAG | F_SECSTAT, "result", NULL, result); | |
980 | } | |
981 | ||
982 | no_cache_dnssec = 0; | |
983 | ||
984 | if (status == STAT_SECURE) | |
985 | cache_secure = 1; | |
986 | else if (status == STAT_BOGUS) | |
987 | no_cache_dnssec = 1; | |
988 | } | |
989 | #endif | |
990 | ||
991 | /* restore CD bit to the value in the query */ | |
992 | if (forward->flags & FREC_CHECKING_DISABLED) | |
993 | header->hb4 |= HB4_CD; | |
994 | else | |
995 | header->hb4 &= ~HB4_CD; | |
996 | ||
997 | if ((nn = process_reply(header, now, server, (size_t)n, check_rebind, no_cache_dnssec, cache_secure, | |
998 | forward->flags & FREC_AD_QUESTION, forward->flags & FREC_DO_QUESTION, | |
999 | forward->flags & FREC_ADDED_PHEADER, forward->flags & FREC_HAS_SUBNET, &forward->source))) | |
1000 | { | |
1001 | header->id = htons(forward->orig_id); | |
1002 | header->hb4 |= HB4_RA; /* recursion if available */ | |
1003 | send_from(forward->fd, option_bool(OPT_NOWILD) || option_bool (OPT_CLEVERBIND), daemon->packet, nn, | |
1004 | &forward->source, &forward->dest, forward->iface); | |
1005 | } | |
1006 | free_frec(forward); /* cancel */ | |
1007 | } | |
1008 | } | |
1009 | ||
1010 | ||
1011 | void receive_query(struct listener *listen, time_t now) | |
1012 | { | |
1013 | struct dns_header *header = (struct dns_header *)daemon->packet; | |
1014 | union mysockaddr source_addr; | |
1015 | unsigned short type; | |
1016 | struct all_addr dst_addr; | |
1017 | struct in_addr netmask, dst_addr_4; | |
1018 | size_t m; | |
1019 | ssize_t n; | |
1020 | int if_index = 0, auth_dns = 0; | |
1021 | #ifdef HAVE_AUTH | |
1022 | int local_auth = 0; | |
1023 | #endif | |
1024 | struct iovec iov[1]; | |
1025 | struct msghdr msg; | |
1026 | struct cmsghdr *cmptr; | |
1027 | union { | |
1028 | struct cmsghdr align; /* this ensures alignment */ | |
1029 | #ifdef HAVE_IPV6 | |
1030 | char control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; | |
1031 | #endif | |
1032 | #if defined(HAVE_LINUX_NETWORK) | |
1033 | char control[CMSG_SPACE(sizeof(struct in_pktinfo))]; | |
1034 | #elif defined(IP_RECVDSTADDR) && defined(HAVE_SOLARIS_NETWORK) | |
1035 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
1036 | CMSG_SPACE(sizeof(unsigned int))]; | |
1037 | #elif defined(IP_RECVDSTADDR) | |
1038 | char control[CMSG_SPACE(sizeof(struct in_addr)) + | |
1039 | CMSG_SPACE(sizeof(struct sockaddr_dl))]; | |
1040 | #endif | |
1041 | } control_u; | |
1042 | #ifdef HAVE_IPV6 | |
1043 | /* Can always get recvd interface for IPv6 */ | |
1044 | int check_dst = !option_bool(OPT_NOWILD) || listen->family == AF_INET6; | |
1045 | #else | |
1046 | int check_dst = !option_bool(OPT_NOWILD); | |
1047 | #endif | |
1048 | ||
1049 | /* packet buffer overwritten */ | |
1050 | daemon->srv_save = NULL; | |
1051 | ||
1052 | dst_addr_4.s_addr = 0; | |
1053 | netmask.s_addr = 0; | |
1054 | ||
1055 | if (option_bool(OPT_NOWILD) && listen->iface) | |
1056 | { | |
1057 | auth_dns = listen->iface->dns_auth; | |
1058 | ||
1059 | if (listen->family == AF_INET) | |
1060 | { | |
1061 | dst_addr_4 = listen->iface->addr.in.sin_addr; | |
1062 | netmask = listen->iface->netmask; | |
1063 | } | |
1064 | } | |
1065 | ||
1066 | iov[0].iov_base = daemon->packet; | |
1067 | iov[0].iov_len = daemon->edns_pktsz; | |
1068 | ||
1069 | msg.msg_control = control_u.control; | |
1070 | msg.msg_controllen = sizeof(control_u); | |
1071 | msg.msg_flags = 0; | |
1072 | msg.msg_name = &source_addr; | |
1073 | msg.msg_namelen = sizeof(source_addr); | |
1074 | msg.msg_iov = iov; | |
1075 | msg.msg_iovlen = 1; | |
1076 | ||
1077 | if ((n = recvmsg(listen->fd, &msg, 0)) == -1) | |
1078 | return; | |
1079 | ||
1080 | if (n < (int)sizeof(struct dns_header) || | |
1081 | (msg.msg_flags & MSG_TRUNC) || | |
1082 | (header->hb3 & HB3_QR)) | |
1083 | return; | |
1084 | ||
1085 | source_addr.sa.sa_family = listen->family; | |
1086 | ||
1087 | if (listen->family == AF_INET) | |
1088 | { | |
1089 | /* Source-port == 0 is an error, we can't send back to that. | |
1090 | http://www.ietf.org/mail-archive/web/dnsop/current/msg11441.html */ | |
1091 | if (source_addr.in.sin_port == 0) | |
1092 | return; | |
1093 | } | |
1094 | #ifdef HAVE_IPV6 | |
1095 | else | |
1096 | { | |
1097 | /* Source-port == 0 is an error, we can't send back to that. */ | |
1098 | if (source_addr.in6.sin6_port == 0) | |
1099 | return; | |
1100 | source_addr.in6.sin6_flowinfo = 0; | |
1101 | } | |
1102 | #endif | |
1103 | ||
1104 | /* We can be configured to only accept queries from at-most-one-hop-away addresses. */ | |
1105 | if (option_bool(OPT_LOCAL_SERVICE)) | |
1106 | { | |
1107 | struct addrlist *addr; | |
1108 | #ifdef HAVE_IPV6 | |
1109 | if (listen->family == AF_INET6) | |
1110 | { | |
1111 | for (addr = daemon->interface_addrs; addr; addr = addr->next) | |
1112 | if ((addr->flags & ADDRLIST_IPV6) && | |
1113 | is_same_net6(&addr->addr.addr.addr6, &source_addr.in6.sin6_addr, addr->prefixlen)) | |
1114 | break; | |
1115 | } | |
1116 | else | |
1117 | #endif | |
1118 | { | |
1119 | struct in_addr netmask; | |
1120 | for (addr = daemon->interface_addrs; addr; addr = addr->next) | |
1121 | { | |
1122 | netmask.s_addr = 0xffffffff << (32 - addr->prefixlen); | |
1123 | if (!(addr->flags & ADDRLIST_IPV6) && | |
1124 | is_same_net(addr->addr.addr.addr4, source_addr.in.sin_addr, netmask)) | |
1125 | break; | |
1126 | } | |
1127 | } | |
1128 | if (!addr) | |
1129 | { | |
1130 | static int warned = 0; | |
1131 | if (!warned) | |
1132 | { | |
1133 | my_syslog(LOG_WARNING, _("Ignoring query from non-local network")); | |
1134 | warned = 1; | |
1135 | } | |
1136 | return; | |
1137 | } | |
1138 | } | |
1139 | ||
1140 | if (check_dst) | |
1141 | { | |
1142 | struct ifreq ifr; | |
1143 | ||
1144 | if (msg.msg_controllen < sizeof(struct cmsghdr)) | |
1145 | return; | |
1146 | ||
1147 | #if defined(HAVE_LINUX_NETWORK) | |
1148 | if (listen->family == AF_INET) | |
1149 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
1150 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO) | |
1151 | { | |
1152 | union { | |
1153 | unsigned char *c; | |
1154 | struct in_pktinfo *p; | |
1155 | } p; | |
1156 | p.c = CMSG_DATA(cmptr); | |
1157 | dst_addr_4 = dst_addr.addr.addr4 = p.p->ipi_spec_dst; | |
1158 | if_index = p.p->ipi_ifindex; | |
1159 | } | |
1160 | #elif defined(IP_RECVDSTADDR) && defined(IP_RECVIF) | |
1161 | if (listen->family == AF_INET) | |
1162 | { | |
1163 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
1164 | { | |
1165 | union { | |
1166 | unsigned char *c; | |
1167 | unsigned int *i; | |
1168 | struct in_addr *a; | |
1169 | #ifndef HAVE_SOLARIS_NETWORK | |
1170 | struct sockaddr_dl *s; | |
1171 | #endif | |
1172 | } p; | |
1173 | p.c = CMSG_DATA(cmptr); | |
1174 | if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVDSTADDR) | |
1175 | dst_addr_4 = dst_addr.addr.addr4 = *(p.a); | |
1176 | else if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF) | |
1177 | #ifdef HAVE_SOLARIS_NETWORK | |
1178 | if_index = *(p.i); | |
1179 | #else | |
1180 | if_index = p.s->sdl_index; | |
1181 | #endif | |
1182 | } | |
1183 | } | |
1184 | #endif | |
1185 | ||
1186 | #ifdef HAVE_IPV6 | |
1187 | if (listen->family == AF_INET6) | |
1188 | { | |
1189 | for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr)) | |
1190 | if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo) | |
1191 | { | |
1192 | union { | |
1193 | unsigned char *c; | |
1194 | struct in6_pktinfo *p; | |
1195 | } p; | |
1196 | p.c = CMSG_DATA(cmptr); | |
1197 | ||
1198 | dst_addr.addr.addr6 = p.p->ipi6_addr; | |
1199 | if_index = p.p->ipi6_ifindex; | |
1200 | } | |
1201 | } | |
1202 | #endif | |
1203 | ||
1204 | /* enforce available interface configuration */ | |
1205 | ||
1206 | if (!indextoname(listen->fd, if_index, ifr.ifr_name)) | |
1207 | return; | |
1208 | ||
1209 | if (!iface_check(listen->family, &dst_addr, ifr.ifr_name, &auth_dns)) | |
1210 | { | |
1211 | if (!option_bool(OPT_CLEVERBIND)) | |
1212 | enumerate_interfaces(0); | |
1213 | if (!loopback_exception(listen->fd, listen->family, &dst_addr, ifr.ifr_name) && | |
1214 | !label_exception(if_index, listen->family, &dst_addr)) | |
1215 | return; | |
1216 | } | |
1217 | ||
1218 | if (listen->family == AF_INET && option_bool(OPT_LOCALISE)) | |
1219 | { | |
1220 | struct irec *iface; | |
1221 | ||
1222 | /* get the netmask of the interface whch has the address we were sent to. | |
1223 | This is no neccessarily the interface we arrived on. */ | |
1224 | ||
1225 | for (iface = daemon->interfaces; iface; iface = iface->next) | |
1226 | if (iface->addr.sa.sa_family == AF_INET && | |
1227 | iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr) | |
1228 | break; | |
1229 | ||
1230 | /* interface may be new */ | |
1231 | if (!iface && !option_bool(OPT_CLEVERBIND)) | |
1232 | enumerate_interfaces(0); | |
1233 | ||
1234 | for (iface = daemon->interfaces; iface; iface = iface->next) | |
1235 | if (iface->addr.sa.sa_family == AF_INET && | |
1236 | iface->addr.in.sin_addr.s_addr == dst_addr_4.s_addr) | |
1237 | break; | |
1238 | ||
1239 | /* If we failed, abandon localisation */ | |
1240 | if (iface) | |
1241 | netmask = iface->netmask; | |
1242 | else | |
1243 | dst_addr_4.s_addr = 0; | |
1244 | } | |
1245 | } | |
1246 | ||
1247 | if (extract_request(header, (size_t)n, daemon->namebuff, &type)) | |
1248 | { | |
1249 | #ifdef HAVE_AUTH | |
1250 | struct auth_zone *zone; | |
1251 | #endif | |
1252 | char *types = querystr(auth_dns ? "auth" : "query", type); | |
1253 | ||
1254 | if (listen->family == AF_INET) | |
1255 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, | |
1256 | (struct all_addr *)&source_addr.in.sin_addr, types); | |
1257 | #ifdef HAVE_IPV6 | |
1258 | else | |
1259 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, | |
1260 | (struct all_addr *)&source_addr.in6.sin6_addr, types); | |
1261 | #endif | |
1262 | ||
1263 | #ifdef HAVE_AUTH | |
1264 | /* find queries for zones we're authoritative for, and answer them directly */ | |
1265 | if (!auth_dns) | |
1266 | for (zone = daemon->auth_zones; zone; zone = zone->next) | |
1267 | if (in_zone(zone, daemon->namebuff, NULL)) | |
1268 | { | |
1269 | auth_dns = 1; | |
1270 | local_auth = 1; | |
1271 | break; | |
1272 | } | |
1273 | #endif | |
1274 | } | |
1275 | ||
1276 | #ifdef HAVE_AUTH | |
1277 | if (auth_dns) | |
1278 | { | |
1279 | m = answer_auth(header, ((char *) header) + daemon->packet_buff_sz, (size_t)n, now, &source_addr, local_auth); | |
1280 | if (m >= 1) | |
1281 | { | |
1282 | send_from(listen->fd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), | |
1283 | (char *)header, m, &source_addr, &dst_addr, if_index); | |
1284 | daemon->auth_answer++; | |
1285 | } | |
1286 | } | |
1287 | else | |
1288 | #endif | |
1289 | { | |
1290 | int ad_reqd, do_bit; | |
1291 | m = answer_request(header, ((char *) header) + daemon->packet_buff_sz, (size_t)n, | |
1292 | dst_addr_4, netmask, now, &ad_reqd, &do_bit); | |
1293 | ||
1294 | if (m >= 1) | |
1295 | { | |
1296 | send_from(listen->fd, option_bool(OPT_NOWILD) || option_bool(OPT_CLEVERBIND), | |
1297 | (char *)header, m, &source_addr, &dst_addr, if_index); | |
1298 | daemon->local_answer++; | |
1299 | } | |
1300 | else if (forward_query(listen->fd, &source_addr, &dst_addr, if_index, | |
1301 | header, (size_t)n, now, NULL, ad_reqd, do_bit)) | |
1302 | daemon->queries_forwarded++; | |
1303 | else | |
1304 | daemon->local_answer++; | |
1305 | } | |
1306 | } | |
1307 | ||
1308 | #ifdef HAVE_DNSSEC | |
1309 | ||
1310 | /* UDP: we've got an unsigned answer, return STAT_INSECURE if we can prove there's no DS | |
1311 | and therefore the answer shouldn't be signed, or STAT_BOGUS if it should be, or | |
1312 | STAT_NEED_DS_NEG and keyname if we need to do the query. */ | |
1313 | static int send_check_sign(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname) | |
1314 | { | |
1315 | struct crec *crecp; | |
1316 | char *name_start = name; | |
1317 | int status = dnssec_chase_cname(now, header, plen, name, keyname); | |
1318 | ||
1319 | if (status != STAT_INSECURE) | |
1320 | return status; | |
1321 | ||
1322 | while (1) | |
1323 | { | |
1324 | crecp = cache_find_by_name(NULL, name_start, now, F_DS); | |
1325 | ||
1326 | if (crecp && (crecp->flags & F_DNSSECOK)) | |
1327 | return (crecp->flags & F_NEG) ? STAT_INSECURE : STAT_BOGUS; | |
1328 | ||
1329 | if (crecp && (crecp->flags & F_NEG) && (name_start = strchr(name_start, '.'))) | |
1330 | { | |
1331 | name_start++; /* chop a label off and try again */ | |
1332 | continue; | |
1333 | } | |
1334 | ||
1335 | /* Reached the root */ | |
1336 | if (!name_start) | |
1337 | return STAT_BOGUS; | |
1338 | ||
1339 | strcpy(keyname, name_start); | |
1340 | return STAT_NEED_DS_NEG; | |
1341 | } | |
1342 | } | |
1343 | ||
1344 | /* Got answer to DS query from send_check_sign, check for proven non-existence, or make the next DS query to try. */ | |
1345 | static int do_check_sign(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class) | |
1346 | ||
1347 | { | |
1348 | char *name_start; | |
1349 | unsigned char *p; | |
1350 | int status = dnssec_validate_ds(now, header, plen, name, keyname, class); | |
1351 | ||
1352 | if (status != STAT_INSECURE) | |
1353 | { | |
1354 | if (status == STAT_NO_DS) | |
1355 | status = STAT_INSECURE; | |
1356 | return status; | |
1357 | } | |
1358 | ||
1359 | p = (unsigned char *)(header+1); | |
1360 | ||
1361 | if (extract_name(header, plen, &p, name, 1, 4) && | |
1362 | (name_start = strchr(name, '.'))) | |
1363 | { | |
1364 | name_start++; /* chop a label off and try again */ | |
1365 | strcpy(keyname, name_start); | |
1366 | return STAT_NEED_DS_NEG; | |
1367 | } | |
1368 | ||
1369 | return STAT_BOGUS; | |
1370 | } | |
1371 | ||
1372 | /* Move toward the root, until we find a signed non-existance of a DS, in which case | |
1373 | an unsigned answer is OK, or we find a signed DS, in which case there should be | |
1374 | a signature, and the answer is BOGUS */ | |
1375 | static int tcp_check_for_unsigned_zone(time_t now, struct dns_header *header, size_t plen, int class, char *name, | |
1376 | char *keyname, struct server *server, int *keycount) | |
1377 | { | |
1378 | size_t m; | |
1379 | unsigned char *packet, *payload; | |
1380 | u16 *length; | |
1381 | unsigned char *p = (unsigned char *)(header+1); | |
1382 | int status; | |
1383 | char *name_start = name; | |
1384 | ||
1385 | /* Get first insecure entry in CNAME chain */ | |
1386 | status = tcp_key_recurse(now, STAT_CHASE_CNAME, header, plen, class, name, keyname, server, keycount); | |
1387 | if (status == STAT_BOGUS) | |
1388 | return STAT_BOGUS; | |
1389 | ||
1390 | if (!(packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ + sizeof(u16)))) | |
1391 | return STAT_BOGUS; | |
1392 | ||
1393 | payload = &packet[2]; | |
1394 | header = (struct dns_header *)payload; | |
1395 | length = (u16 *)packet; | |
1396 | ||
1397 | while (1) | |
1398 | { | |
1399 | unsigned char *newhash, hash[HASH_SIZE]; | |
1400 | unsigned char c1, c2; | |
1401 | struct crec *crecp = cache_find_by_name(NULL, name_start, now, F_DS); | |
1402 | ||
1403 | if (--(*keycount) == 0) | |
1404 | { | |
1405 | free(packet); | |
1406 | return STAT_BOGUS; | |
1407 | } | |
1408 | ||
1409 | if (crecp && (crecp->flags & F_DNSSECOK)) | |
1410 | { | |
1411 | free(packet); | |
1412 | return (crecp->flags & F_NEG) ? STAT_INSECURE : STAT_BOGUS; | |
1413 | } | |
1414 | ||
1415 | /* If we have cached insecurely that a DS doesn't exist, | |
1416 | ise that is a hit for where to start looking for the secure one */ | |
1417 | if (crecp && (crecp->flags & F_NEG) && (name_start = strchr(name_start, '.'))) | |
1418 | { | |
1419 | name_start++; /* chop a label off and try again */ | |
1420 | continue; | |
1421 | } | |
1422 | ||
1423 | /* reached the root */ | |
1424 | if (!name_start) | |
1425 | { | |
1426 | free(packet); | |
1427 | return STAT_BOGUS; | |
1428 | } | |
1429 | ||
1430 | m = dnssec_generate_query(header, ((char *) header) + 65536, name_start, class, T_DS, &server->addr); | |
1431 | ||
1432 | /* We rely on the question section coming back unchanged, ensure it is with the hash. */ | |
1433 | if ((newhash = hash_questions(header, (unsigned int)m, name))) | |
1434 | { | |
1435 | memcpy(hash, newhash, HASH_SIZE); | |
1436 | ||
1437 | *length = htons(m); | |
1438 | ||
1439 | if (read_write(server->tcpfd, packet, m + sizeof(u16), 0) && | |
1440 | read_write(server->tcpfd, &c1, 1, 1) && | |
1441 | read_write(server->tcpfd, &c2, 1, 1) && | |
1442 | read_write(server->tcpfd, payload, (c1 << 8) | c2, 1)) | |
1443 | { | |
1444 | m = (c1 << 8) | c2; | |
1445 | ||
1446 | newhash = hash_questions(header, (unsigned int)m, name); | |
1447 | if (newhash && memcmp(hash, newhash, HASH_SIZE) == 0) | |
1448 | { | |
1449 | /* Note this trashes all three name workspaces */ | |
1450 | status = tcp_key_recurse(now, STAT_NEED_DS_NEG, header, m, class, name, keyname, server, keycount); | |
1451 | ||
1452 | /* We've found a DS which proves the bit of the DNS where the | |
1453 | original query is, is unsigned, so the answer is OK, | |
1454 | if unvalidated. */ | |
1455 | if (status == STAT_NO_DS) | |
1456 | { | |
1457 | free(packet); | |
1458 | return STAT_INSECURE; | |
1459 | } | |
1460 | ||
1461 | /* No DS, not got to DNSSEC-land yet, go up. */ | |
1462 | if (status == STAT_INSECURE) | |
1463 | { | |
1464 | p = (unsigned char *)(header+1); | |
1465 | ||
1466 | if (extract_name(header, plen, &p, name, 1, 4) && | |
1467 | (name_start = strchr(name, '.'))) | |
1468 | { | |
1469 | name_start++; /* chop a label off and try again */ | |
1470 | continue; | |
1471 | } | |
1472 | } | |
1473 | } | |
1474 | } | |
1475 | } | |
1476 | ||
1477 | free(packet); | |
1478 | ||
1479 | return STAT_BOGUS; | |
1480 | } | |
1481 | } | |
1482 | ||
1483 | static int tcp_key_recurse(time_t now, int status, struct dns_header *header, size_t n, | |
1484 | int class, char *name, char *keyname, struct server *server, int *keycount) | |
1485 | { | |
1486 | /* Recurse up the key heirarchy */ | |
1487 | int new_status; | |
1488 | ||
1489 | /* limit the amount of work we do, to avoid cycling forever on loops in the DNS */ | |
1490 | if (--(*keycount) == 0) | |
1491 | return STAT_INSECURE; | |
1492 | ||
1493 | if (status == STAT_NEED_KEY) | |
1494 | new_status = dnssec_validate_by_ds(now, header, n, name, keyname, class); | |
1495 | else if (status == STAT_NEED_DS || status == STAT_NEED_DS_NEG) | |
1496 | { | |
1497 | new_status = dnssec_validate_ds(now, header, n, name, keyname, class); | |
1498 | if (status == STAT_NEED_DS && new_status == STAT_NO_DS) | |
1499 | new_status = STAT_INSECURE; | |
1500 | } | |
1501 | else if (status == STAT_CHASE_CNAME) | |
1502 | new_status = dnssec_chase_cname(now, header, n, name, keyname); | |
1503 | else | |
1504 | { | |
1505 | new_status = dnssec_validate_reply(now, header, n, name, keyname, &class, NULL); | |
1506 | ||
1507 | if (new_status == STAT_NO_SIG) | |
1508 | { | |
1509 | if (option_bool(OPT_DNSSEC_NO_SIGN)) | |
1510 | new_status = tcp_check_for_unsigned_zone(now, header, n, class, name, keyname, server, keycount); | |
1511 | else | |
1512 | new_status = STAT_INSECURE; | |
1513 | } | |
1514 | } | |
1515 | ||
1516 | /* Can't validate because we need a key/DS whose name now in keyname. | |
1517 | Make query for same, and recurse to validate */ | |
1518 | if (new_status == STAT_NEED_DS || new_status == STAT_NEED_KEY) | |
1519 | { | |
1520 | size_t m; | |
1521 | unsigned char *packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ + sizeof(u16)); | |
1522 | unsigned char *payload = &packet[2]; | |
1523 | struct dns_header *new_header = (struct dns_header *)payload; | |
1524 | u16 *length = (u16 *)packet; | |
1525 | unsigned char c1, c2; | |
1526 | ||
1527 | if (!packet) | |
1528 | return STAT_INSECURE; | |
1529 | ||
1530 | another_tcp_key: | |
1531 | m = dnssec_generate_query(new_header, ((char *) new_header) + 65536, keyname, class, | |
1532 | new_status == STAT_NEED_KEY ? T_DNSKEY : T_DS, &server->addr); | |
1533 | ||
1534 | *length = htons(m); | |
1535 | ||
1536 | if (!read_write(server->tcpfd, packet, m + sizeof(u16), 0) || | |
1537 | !read_write(server->tcpfd, &c1, 1, 1) || | |
1538 | !read_write(server->tcpfd, &c2, 1, 1) || | |
1539 | !read_write(server->tcpfd, payload, (c1 << 8) | c2, 1)) | |
1540 | new_status = STAT_INSECURE; | |
1541 | else | |
1542 | { | |
1543 | m = (c1 << 8) | c2; | |
1544 | ||
1545 | new_status = tcp_key_recurse(now, new_status, new_header, m, class, name, keyname, server, keycount); | |
1546 | ||
1547 | if (new_status == STAT_SECURE) | |
1548 | { | |
1549 | /* Reached a validated record, now try again at this level. | |
1550 | Note that we may get ANOTHER NEED_* if an answer needs more than one key. | |
1551 | If so, go round again. */ | |
1552 | ||
1553 | if (status == STAT_NEED_KEY) | |
1554 | new_status = dnssec_validate_by_ds(now, header, n, name, keyname, class); | |
1555 | else if (status == STAT_NEED_DS || status == STAT_NEED_DS_NEG) | |
1556 | { | |
1557 | new_status = dnssec_validate_ds(now, header, n, name, keyname, class); | |
1558 | if (status == STAT_NEED_DS && new_status == STAT_NO_DS) | |
1559 | new_status = STAT_INSECURE; /* Validated no DS */ | |
1560 | } | |
1561 | else if (status == STAT_CHASE_CNAME) | |
1562 | new_status = dnssec_chase_cname(now, header, n, name, keyname); | |
1563 | else | |
1564 | { | |
1565 | new_status = dnssec_validate_reply(now, header, n, name, keyname, &class, NULL); | |
1566 | ||
1567 | if (new_status == STAT_NO_SIG) | |
1568 | { | |
1569 | if (option_bool(OPT_DNSSEC_NO_SIGN)) | |
1570 | new_status = tcp_check_for_unsigned_zone(now, header, n, class, name, keyname, server, keycount); | |
1571 | else | |
1572 | new_status = STAT_INSECURE; | |
1573 | } | |
1574 | } | |
1575 | ||
1576 | if (new_status == STAT_NEED_DS || new_status == STAT_NEED_KEY) | |
1577 | goto another_tcp_key; | |
1578 | } | |
1579 | } | |
1580 | ||
1581 | free(packet); | |
1582 | } | |
1583 | return new_status; | |
1584 | } | |
1585 | #endif | |
1586 | ||
1587 | ||
1588 | /* The daemon forks before calling this: it should deal with one connection, | |
1589 | blocking as neccessary, and then return. Note, need to be a bit careful | |
1590 | about resources for debug mode, when the fork is suppressed: that's | |
1591 | done by the caller. */ | |
1592 | unsigned char *tcp_request(int confd, time_t now, | |
1593 | union mysockaddr *local_addr, struct in_addr netmask, int auth_dns) | |
1594 | { | |
1595 | size_t size = 0; | |
1596 | int norebind = 0; | |
1597 | #ifdef HAVE_AUTH | |
1598 | int local_auth = 0; | |
1599 | #endif | |
1600 | int checking_disabled, ad_question, do_bit, added_pheader = 0; | |
1601 | int check_subnet, no_cache_dnssec = 0, cache_secure = 0; | |
1602 | size_t m; | |
1603 | unsigned short qtype; | |
1604 | unsigned int gotname; | |
1605 | unsigned char c1, c2; | |
1606 | /* Max TCP packet + slop + size */ | |
1607 | unsigned char *packet = whine_malloc(65536 + MAXDNAME + RRFIXEDSZ + sizeof(u16)); | |
1608 | unsigned char *payload = &packet[2]; | |
1609 | /* largest field in header is 16-bits, so this is still sufficiently aligned */ | |
1610 | struct dns_header *header = (struct dns_header *)payload; | |
1611 | u16 *length = (u16 *)packet; | |
1612 | struct server *last_server; | |
1613 | struct in_addr dst_addr_4; | |
1614 | union mysockaddr peer_addr; | |
1615 | socklen_t peer_len = sizeof(union mysockaddr); | |
1616 | ||
1617 | if (getpeername(confd, (struct sockaddr *)&peer_addr, &peer_len) == -1) | |
1618 | return packet; | |
1619 | ||
1620 | /* We can be configured to only accept queries from at-most-one-hop-away addresses. */ | |
1621 | if (option_bool(OPT_LOCAL_SERVICE)) | |
1622 | { | |
1623 | struct addrlist *addr; | |
1624 | #ifdef HAVE_IPV6 | |
1625 | if (peer_addr.sa.sa_family == AF_INET6) | |
1626 | { | |
1627 | for (addr = daemon->interface_addrs; addr; addr = addr->next) | |
1628 | if ((addr->flags & ADDRLIST_IPV6) && | |
1629 | is_same_net6(&addr->addr.addr.addr6, &peer_addr.in6.sin6_addr, addr->prefixlen)) | |
1630 | break; | |
1631 | } | |
1632 | else | |
1633 | #endif | |
1634 | { | |
1635 | struct in_addr netmask; | |
1636 | for (addr = daemon->interface_addrs; addr; addr = addr->next) | |
1637 | { | |
1638 | netmask.s_addr = 0xffffffff << (32 - addr->prefixlen); | |
1639 | if (!(addr->flags & ADDRLIST_IPV6) && | |
1640 | is_same_net(addr->addr.addr.addr4, peer_addr.in.sin_addr, netmask)) | |
1641 | break; | |
1642 | } | |
1643 | } | |
1644 | if (!addr) | |
1645 | { | |
1646 | my_syslog(LOG_WARNING, _("Ignoring query from non-local network")); | |
1647 | return packet; | |
1648 | } | |
1649 | } | |
1650 | ||
1651 | while (1) | |
1652 | { | |
1653 | if (!packet || | |
1654 | !read_write(confd, &c1, 1, 1) || !read_write(confd, &c2, 1, 1) || | |
1655 | !(size = c1 << 8 | c2) || | |
1656 | !read_write(confd, payload, size, 1)) | |
1657 | return packet; | |
1658 | ||
1659 | if (size < (int)sizeof(struct dns_header)) | |
1660 | continue; | |
1661 | ||
1662 | check_subnet = 0; | |
1663 | ||
1664 | /* save state of "cd" flag in query */ | |
1665 | if ((checking_disabled = header->hb4 & HB4_CD)) | |
1666 | no_cache_dnssec = 1; | |
1667 | ||
1668 | if ((gotname = extract_request(header, (unsigned int)size, daemon->namebuff, &qtype))) | |
1669 | { | |
1670 | #ifdef HAVE_AUTH | |
1671 | struct auth_zone *zone; | |
1672 | #endif | |
1673 | char *types = querystr(auth_dns ? "auth" : "query", qtype); | |
1674 | ||
1675 | if (peer_addr.sa.sa_family == AF_INET) | |
1676 | log_query(F_QUERY | F_IPV4 | F_FORWARD, daemon->namebuff, | |
1677 | (struct all_addr *)&peer_addr.in.sin_addr, types); | |
1678 | #ifdef HAVE_IPV6 | |
1679 | else | |
1680 | log_query(F_QUERY | F_IPV6 | F_FORWARD, daemon->namebuff, | |
1681 | (struct all_addr *)&peer_addr.in6.sin6_addr, types); | |
1682 | #endif | |
1683 | ||
1684 | #ifdef HAVE_AUTH | |
1685 | /* find queries for zones we're authoritative for, and answer them directly */ | |
1686 | if (!auth_dns) | |
1687 | for (zone = daemon->auth_zones; zone; zone = zone->next) | |
1688 | if (in_zone(zone, daemon->namebuff, NULL)) | |
1689 | { | |
1690 | auth_dns = 1; | |
1691 | local_auth = 1; | |
1692 | break; | |
1693 | } | |
1694 | #endif | |
1695 | } | |
1696 | ||
1697 | if (local_addr->sa.sa_family == AF_INET) | |
1698 | dst_addr_4 = local_addr->in.sin_addr; | |
1699 | else | |
1700 | dst_addr_4.s_addr = 0; | |
1701 | ||
1702 | #ifdef HAVE_AUTH | |
1703 | if (auth_dns) | |
1704 | m = answer_auth(header, ((char *) header) + 65536, (size_t)size, now, &peer_addr, local_auth); | |
1705 | else | |
1706 | #endif | |
1707 | { | |
1708 | /* m > 0 if answered from cache */ | |
1709 | m = answer_request(header, ((char *) header) + 65536, (size_t)size, | |
1710 | dst_addr_4, netmask, now, &ad_question, &do_bit); | |
1711 | ||
1712 | /* Do this by steam now we're not in the select() loop */ | |
1713 | check_log_writer(NULL); | |
1714 | ||
1715 | if (m == 0) | |
1716 | { | |
1717 | unsigned int flags = 0; | |
1718 | struct all_addr *addrp = NULL; | |
1719 | int type = 0; | |
1720 | char *domain = NULL; | |
1721 | ||
1722 | if (option_bool(OPT_ADD_MAC)) | |
1723 | size = add_mac(header, size, ((char *) header) + 65536, &peer_addr); | |
1724 | ||
1725 | if (option_bool(OPT_CLIENT_SUBNET)) | |
1726 | { | |
1727 | size_t new = add_source_addr(header, size, ((char *) header) + 65536, &peer_addr); | |
1728 | if (size != new) | |
1729 | { | |
1730 | size = new; | |
1731 | check_subnet = 1; | |
1732 | } | |
1733 | } | |
1734 | ||
1735 | if (gotname) | |
1736 | flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind); | |
1737 | ||
1738 | if (type != 0 || option_bool(OPT_ORDER) || !daemon->last_server) | |
1739 | last_server = daemon->servers; | |
1740 | else | |
1741 | last_server = daemon->last_server; | |
1742 | ||
1743 | if (!flags && last_server) | |
1744 | { | |
1745 | struct server *firstsendto = NULL; | |
1746 | #ifdef HAVE_DNSSEC | |
1747 | unsigned char *newhash, hash[HASH_SIZE]; | |
1748 | if ((newhash = hash_questions(header, (unsigned int)size, daemon->namebuff))) | |
1749 | memcpy(hash, newhash, HASH_SIZE); | |
1750 | else | |
1751 | memset(hash, 0, HASH_SIZE); | |
1752 | #else | |
1753 | unsigned int crc = questions_crc(header, (unsigned int)size, daemon->namebuff); | |
1754 | #endif | |
1755 | /* Loop round available servers until we succeed in connecting to one. | |
1756 | Note that this code subtley ensures that consecutive queries on this connection | |
1757 | which can go to the same server, do so. */ | |
1758 | while (1) | |
1759 | { | |
1760 | if (!firstsendto) | |
1761 | firstsendto = last_server; | |
1762 | else | |
1763 | { | |
1764 | if (!(last_server = last_server->next)) | |
1765 | last_server = daemon->servers; | |
1766 | ||
1767 | if (last_server == firstsendto) | |
1768 | break; | |
1769 | } | |
1770 | ||
1771 | /* server for wrong domain */ | |
1772 | if (type != (last_server->flags & SERV_TYPE) || | |
1773 | (type == SERV_HAS_DOMAIN && !hostname_isequal(domain, last_server->domain))) | |
1774 | continue; | |
1775 | ||
1776 | if (last_server->tcpfd == -1) | |
1777 | { | |
1778 | if ((last_server->tcpfd = socket(last_server->addr.sa.sa_family, SOCK_STREAM, 0)) == -1) | |
1779 | continue; | |
1780 | ||
1781 | if ((!local_bind(last_server->tcpfd, &last_server->source_addr, last_server->interface, 1) || | |
1782 | connect(last_server->tcpfd, &last_server->addr.sa, sa_len(&last_server->addr)) == -1)) | |
1783 | { | |
1784 | close(last_server->tcpfd); | |
1785 | last_server->tcpfd = -1; | |
1786 | continue; | |
1787 | } | |
1788 | ||
1789 | #ifdef HAVE_DNSSEC | |
1790 | if (option_bool(OPT_DNSSEC_VALID)) | |
1791 | { | |
1792 | size_t new_size = add_do_bit(header, size, ((char *) header) + 65536); | |
1793 | ||
1794 | /* For debugging, set Checking Disabled, otherwise, have the upstream check too, | |
1795 | this allows it to select auth servers when one is returning bad data. */ | |
1796 | if (option_bool(OPT_DNSSEC_DEBUG)) | |
1797 | header->hb4 |= HB4_CD; | |
1798 | ||
1799 | if (size != new_size) | |
1800 | added_pheader = 1; | |
1801 | ||
1802 | size = new_size; | |
1803 | } | |
1804 | #endif | |
1805 | ||
1806 | #ifdef HAVE_CONNTRACK | |
1807 | /* Copy connection mark of incoming query to outgoing connection. */ | |
1808 | if (option_bool(OPT_CONNTRACK)) | |
1809 | { | |
1810 | unsigned int mark; | |
1811 | struct all_addr local; | |
1812 | #ifdef HAVE_IPV6 | |
1813 | if (local_addr->sa.sa_family == AF_INET6) | |
1814 | local.addr.addr6 = local_addr->in6.sin6_addr; | |
1815 | else | |
1816 | #endif | |
1817 | local.addr.addr4 = local_addr->in.sin_addr; | |
1818 | ||
1819 | if (get_incoming_mark(&peer_addr, &local, 1, &mark)) | |
1820 | setsockopt(last_server->tcpfd, SOL_SOCKET, SO_MARK, &mark, sizeof(unsigned int)); | |
1821 | } | |
1822 | #endif | |
1823 | } | |
1824 | ||
1825 | *length = htons(size); | |
1826 | ||
1827 | if (!read_write(last_server->tcpfd, packet, size + sizeof(u16), 0) || | |
1828 | !read_write(last_server->tcpfd, &c1, 1, 1) || | |
1829 | !read_write(last_server->tcpfd, &c2, 1, 1) || | |
1830 | !read_write(last_server->tcpfd, payload, (c1 << 8) | c2, 1)) | |
1831 | { | |
1832 | close(last_server->tcpfd); | |
1833 | last_server->tcpfd = -1; | |
1834 | continue; | |
1835 | } | |
1836 | ||
1837 | m = (c1 << 8) | c2; | |
1838 | ||
1839 | if (!gotname) | |
1840 | strcpy(daemon->namebuff, "query"); | |
1841 | if (last_server->addr.sa.sa_family == AF_INET) | |
1842 | log_query(F_SERVER | F_IPV4 | F_FORWARD, daemon->namebuff, | |
1843 | (struct all_addr *)&last_server->addr.in.sin_addr, NULL); | |
1844 | #ifdef HAVE_IPV6 | |
1845 | else | |
1846 | log_query(F_SERVER | F_IPV6 | F_FORWARD, daemon->namebuff, | |
1847 | (struct all_addr *)&last_server->addr.in6.sin6_addr, NULL); | |
1848 | #endif | |
1849 | ||
1850 | #ifdef HAVE_DNSSEC | |
1851 | if (option_bool(OPT_DNSSEC_VALID) && !checking_disabled) | |
1852 | { | |
1853 | int keycount = DNSSEC_WORK; /* Limit to number of DNSSEC questions, to catch loops and avoid filling cache. */ | |
1854 | int status = tcp_key_recurse(now, STAT_TRUNCATED, header, m, 0, daemon->namebuff, daemon->keyname, last_server, &keycount); | |
1855 | char *result; | |
1856 | ||
1857 | if (keycount == 0) | |
1858 | result = "ABANDONED"; | |
1859 | else | |
1860 | result = (status == STAT_SECURE ? "SECURE" : (status == STAT_INSECURE ? "INSECURE" : "BOGUS")); | |
1861 | ||
1862 | log_query(F_KEYTAG | F_SECSTAT, "result", NULL, result); | |
1863 | ||
1864 | if (status == STAT_BOGUS) | |
1865 | no_cache_dnssec = 1; | |
1866 | ||
1867 | if (status == STAT_SECURE) | |
1868 | cache_secure = 1; | |
1869 | } | |
1870 | #endif | |
1871 | ||
1872 | /* restore CD bit to the value in the query */ | |
1873 | if (checking_disabled) | |
1874 | header->hb4 |= HB4_CD; | |
1875 | else | |
1876 | header->hb4 &= ~HB4_CD; | |
1877 | ||
1878 | /* There's no point in updating the cache, since this process will exit and | |
1879 | lose the information after a few queries. We make this call for the alias and | |
1880 | bogus-nxdomain side-effects. */ | |
1881 | /* If the crc of the question section doesn't match the crc we sent, then | |
1882 | someone might be attempting to insert bogus values into the cache by | |
1883 | sending replies containing questions and bogus answers. */ | |
1884 | #ifdef HAVE_DNSSEC | |
1885 | newhash = hash_questions(header, (unsigned int)m, daemon->namebuff); | |
1886 | if (!newhash || memcmp(hash, newhash, HASH_SIZE) != 0) | |
1887 | { | |
1888 | m = 0; | |
1889 | break; | |
1890 | } | |
1891 | #else | |
1892 | if (crc != questions_crc(header, (unsigned int)m, daemon->namebuff)) | |
1893 | { | |
1894 | m = 0; | |
1895 | break; | |
1896 | } | |
1897 | #endif | |
1898 | ||
1899 | m = process_reply(header, now, last_server, (unsigned int)m, | |
1900 | option_bool(OPT_NO_REBIND) && !norebind, no_cache_dnssec, | |
1901 | cache_secure, ad_question, do_bit, added_pheader, check_subnet, &peer_addr); | |
1902 | ||
1903 | break; | |
1904 | } | |
1905 | } | |
1906 | ||
1907 | /* In case of local answer or no connections made. */ | |
1908 | if (m == 0) | |
1909 | m = setup_reply(header, (unsigned int)size, addrp, flags, daemon->local_ttl); | |
1910 | } | |
1911 | } | |
1912 | ||
1913 | check_log_writer(NULL); | |
1914 | ||
1915 | *length = htons(m); | |
1916 | ||
1917 | if (m == 0 || !read_write(confd, packet, m + sizeof(u16), 0)) | |
1918 | return packet; | |
1919 | } | |
1920 | } | |
1921 | ||
1922 | static struct frec *allocate_frec(time_t now) | |
1923 | { | |
1924 | struct frec *f; | |
1925 | ||
1926 | if ((f = (struct frec *)whine_malloc(sizeof(struct frec)))) | |
1927 | { | |
1928 | f->next = daemon->frec_list; | |
1929 | f->time = now; | |
1930 | f->sentto = NULL; | |
1931 | f->rfd4 = NULL; | |
1932 | f->flags = 0; | |
1933 | #ifdef HAVE_IPV6 | |
1934 | f->rfd6 = NULL; | |
1935 | #endif | |
1936 | #ifdef HAVE_DNSSEC | |
1937 | f->dependent = NULL; | |
1938 | f->blocking_query = NULL; | |
1939 | f->stash = NULL; | |
1940 | #endif | |
1941 | daemon->frec_list = f; | |
1942 | } | |
1943 | ||
1944 | return f; | |
1945 | } | |
1946 | ||
1947 | static struct randfd *allocate_rfd(int family) | |
1948 | { | |
1949 | static int finger = 0; | |
1950 | int i; | |
1951 | ||
1952 | /* limit the number of sockets we have open to avoid starvation of | |
1953 | (eg) TFTP. Once we have a reasonable number, randomness should be OK */ | |
1954 | ||
1955 | for (i = 0; i < RANDOM_SOCKS; i++) | |
1956 | if (daemon->randomsocks[i].refcount == 0) | |
1957 | { | |
1958 | if ((daemon->randomsocks[i].fd = random_sock(family)) == -1) | |
1959 | break; | |
1960 | ||
1961 | daemon->randomsocks[i].refcount = 1; | |
1962 | daemon->randomsocks[i].family = family; | |
1963 | return &daemon->randomsocks[i]; | |
1964 | } | |
1965 | ||
1966 | /* No free ones or cannot get new socket, grab an existing one */ | |
1967 | for (i = 0; i < RANDOM_SOCKS; i++) | |
1968 | { | |
1969 | int j = (i+finger) % RANDOM_SOCKS; | |
1970 | if (daemon->randomsocks[j].refcount != 0 && | |
1971 | daemon->randomsocks[j].family == family && | |
1972 | daemon->randomsocks[j].refcount != 0xffff) | |
1973 | { | |
1974 | finger = j; | |
1975 | daemon->randomsocks[j].refcount++; | |
1976 | return &daemon->randomsocks[j]; | |
1977 | } | |
1978 | } | |
1979 | ||
1980 | return NULL; /* doom */ | |
1981 | } | |
1982 | static void free_frec(struct frec *f) | |
1983 | { | |
1984 | if (f->rfd4 && --(f->rfd4->refcount) == 0) | |
1985 | close(f->rfd4->fd); | |
1986 | ||
1987 | f->rfd4 = NULL; | |
1988 | f->sentto = NULL; | |
1989 | f->flags = 0; | |
1990 | ||
1991 | #ifdef HAVE_IPV6 | |
1992 | if (f->rfd6 && --(f->rfd6->refcount) == 0) | |
1993 | close(f->rfd6->fd); | |
1994 | ||
1995 | f->rfd6 = NULL; | |
1996 | #endif | |
1997 | ||
1998 | #ifdef HAVE_DNSSEC | |
1999 | if (f->stash) | |
2000 | { | |
2001 | blockdata_free(f->stash); | |
2002 | f->stash = NULL; | |
2003 | } | |
2004 | ||
2005 | /* Anything we're waiting on is pointless now, too */ | |
2006 | if (f->blocking_query) | |
2007 | free_frec(f->blocking_query); | |
2008 | f->blocking_query = NULL; | |
2009 | f->dependent = NULL; | |
2010 | #endif | |
2011 | } | |
2012 | ||
2013 | /* if wait==NULL return a free or older than TIMEOUT record. | |
2014 | else return *wait zero if one available, or *wait is delay to | |
2015 | when the oldest in-use record will expire. Impose an absolute | |
2016 | limit of 4*TIMEOUT before we wipe things (for random sockets). | |
2017 | If force is set, always return a result, even if we have | |
2018 | to allocate above the limit. */ | |
2019 | struct frec *get_new_frec(time_t now, int *wait, int force) | |
2020 | { | |
2021 | struct frec *f, *oldest, *target; | |
2022 | int count; | |
2023 | ||
2024 | if (wait) | |
2025 | *wait = 0; | |
2026 | ||
2027 | for (f = daemon->frec_list, oldest = NULL, target = NULL, count = 0; f; f = f->next, count++) | |
2028 | if (!f->sentto) | |
2029 | target = f; | |
2030 | else | |
2031 | { | |
2032 | if (difftime(now, f->time) >= 4*TIMEOUT) | |
2033 | { | |
2034 | free_frec(f); | |
2035 | target = f; | |
2036 | } | |
2037 | ||
2038 | if (!oldest || difftime(f->time, oldest->time) <= 0) | |
2039 | oldest = f; | |
2040 | } | |
2041 | ||
2042 | if (target) | |
2043 | { | |
2044 | target->time = now; | |
2045 | return target; | |
2046 | } | |
2047 | ||
2048 | /* can't find empty one, use oldest if there is one | |
2049 | and it's older than timeout */ | |
2050 | if (oldest && ((int)difftime(now, oldest->time)) >= TIMEOUT) | |
2051 | { | |
2052 | /* keep stuff for twice timeout if we can by allocating a new | |
2053 | record instead */ | |
2054 | if (difftime(now, oldest->time) < 2*TIMEOUT && | |
2055 | count <= daemon->ftabsize && | |
2056 | (f = allocate_frec(now))) | |
2057 | return f; | |
2058 | ||
2059 | if (!wait) | |
2060 | { | |
2061 | free_frec(oldest); | |
2062 | oldest->time = now; | |
2063 | } | |
2064 | return oldest; | |
2065 | } | |
2066 | ||
2067 | /* none available, calculate time 'till oldest record expires */ | |
2068 | if (!force && count > daemon->ftabsize) | |
2069 | { | |
2070 | static time_t last_log = 0; | |
2071 | ||
2072 | if (oldest && wait) | |
2073 | *wait = oldest->time + (time_t)TIMEOUT - now; | |
2074 | ||
2075 | if ((int)difftime(now, last_log) > 5) | |
2076 | { | |
2077 | last_log = now; | |
2078 | my_syslog(LOG_WARNING, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon->ftabsize); | |
2079 | } | |
2080 | ||
2081 | return NULL; | |
2082 | } | |
2083 | ||
2084 | if (!(f = allocate_frec(now)) && wait) | |
2085 | /* wait one second on malloc failure */ | |
2086 | *wait = 1; | |
2087 | ||
2088 | return f; /* OK if malloc fails and this is NULL */ | |
2089 | } | |
2090 | ||
2091 | /* crc is all-ones if not known. */ | |
2092 | static struct frec *lookup_frec(unsigned short id, void *hash) | |
2093 | { | |
2094 | struct frec *f; | |
2095 | ||
2096 | for(f = daemon->frec_list; f; f = f->next) | |
2097 | if (f->sentto && f->new_id == id && | |
2098 | (!hash || memcmp(hash, f->hash, HASH_SIZE) == 0)) | |
2099 | return f; | |
2100 | ||
2101 | return NULL; | |
2102 | } | |
2103 | ||
2104 | static struct frec *lookup_frec_by_sender(unsigned short id, | |
2105 | union mysockaddr *addr, | |
2106 | void *hash) | |
2107 | { | |
2108 | struct frec *f; | |
2109 | ||
2110 | for(f = daemon->frec_list; f; f = f->next) | |
2111 | if (f->sentto && | |
2112 | f->orig_id == id && | |
2113 | memcmp(hash, f->hash, HASH_SIZE) == 0 && | |
2114 | sockaddr_isequal(&f->source, addr)) | |
2115 | return f; | |
2116 | ||
2117 | return NULL; | |
2118 | } | |
2119 | ||
2120 | /* A server record is going away, remove references to it */ | |
2121 | void server_gone(struct server *server) | |
2122 | { | |
2123 | struct frec *f; | |
2124 | ||
2125 | for (f = daemon->frec_list; f; f = f->next) | |
2126 | if (f->sentto && f->sentto == server) | |
2127 | free_frec(f); | |
2128 | ||
2129 | if (daemon->last_server == server) | |
2130 | daemon->last_server = NULL; | |
2131 | ||
2132 | if (daemon->srv_save == server) | |
2133 | daemon->srv_save = NULL; | |
2134 | } | |
2135 | ||
2136 | /* return unique random ids. */ | |
2137 | static unsigned short get_id(void) | |
2138 | { | |
2139 | unsigned short ret = 0; | |
2140 | ||
2141 | do | |
2142 | ret = rand16(); | |
2143 | while (lookup_frec(ret, NULL)); | |
2144 | ||
2145 | return ret; | |
2146 | } | |
2147 | ||
2148 | ||
2149 | ||
2150 | ||
2151 |