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ec2c5e43 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
beef6a5f LP |
22 | #include <sd-messages.h> |
23 | ||
ec2c5e43 | 24 | #include "af-list.h" |
b5efdb8a | 25 | #include "alloc-util.h" |
f52e61da | 26 | #include "dns-domain.h" |
3ffd4af2 LP |
27 | #include "fd-util.h" |
28 | #include "random-util.h" | |
7778dfff | 29 | #include "resolved-dns-cache.h" |
3ffd4af2 LP |
30 | #include "resolved-dns-transaction.h" |
31 | #include "resolved-llmnr.h" | |
8b43440b | 32 | #include "string-table.h" |
ec2c5e43 | 33 | |
c61d2b44 LP |
34 | static void dns_transaction_reset_answer(DnsTransaction *t) { |
35 | assert(t); | |
36 | ||
37 | t->received = dns_packet_unref(t->received); | |
38 | t->answer = dns_answer_unref(t->answer); | |
39 | t->answer_rcode = 0; | |
40 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; | |
41 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; | |
42 | t->answer_authenticated = false; | |
d3760be0 | 43 | t->answer_nsec_ttl = (uint32_t) -1; |
c61d2b44 LP |
44 | } |
45 | ||
f32f0e57 LP |
46 | static void dns_transaction_close_connection(DnsTransaction *t) { |
47 | assert(t); | |
48 | ||
49 | t->stream = dns_stream_free(t->stream); | |
50 | t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); | |
51 | t->dns_udp_fd = safe_close(t->dns_udp_fd); | |
52 | } | |
53 | ||
f535705a | 54 | static void dns_transaction_stop_timeout(DnsTransaction *t) { |
97cc656c LP |
55 | assert(t); |
56 | ||
57 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
97cc656c LP |
58 | } |
59 | ||
ec2c5e43 | 60 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { |
801ad6a6 | 61 | DnsQueryCandidate *c; |
ec2c5e43 | 62 | DnsZoneItem *i; |
547973de | 63 | DnsTransaction *z; |
ec2c5e43 LP |
64 | |
65 | if (!t) | |
66 | return NULL; | |
67 | ||
51e399bc LP |
68 | log_debug("Freeing transaction %" PRIu16 ".", t->id); |
69 | ||
f32f0e57 | 70 | dns_transaction_close_connection(t); |
f535705a | 71 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 72 | |
ec2c5e43 | 73 | dns_packet_unref(t->sent); |
c61d2b44 | 74 | dns_transaction_reset_answer(t); |
ec2c5e43 | 75 | |
8300ba21 | 76 | dns_server_unref(t->server); |
ec2c5e43 LP |
77 | |
78 | if (t->scope) { | |
f9ebb22a LP |
79 | hashmap_remove_value(t->scope->transactions_by_key, t->key, t); |
80 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
ec2c5e43 LP |
81 | |
82 | if (t->id != 0) | |
83 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
84 | } | |
85 | ||
547973de | 86 | while ((c = set_steal_first(t->notify_query_candidates))) |
801ad6a6 | 87 | set_remove(c->transactions, t); |
547973de | 88 | set_free(t->notify_query_candidates); |
801ad6a6 | 89 | |
547973de | 90 | while ((i = set_steal_first(t->notify_zone_items))) |
ec2c5e43 | 91 | i->probe_transaction = NULL; |
547973de LP |
92 | set_free(t->notify_zone_items); |
93 | ||
94 | while ((z = set_steal_first(t->notify_transactions))) | |
95 | set_remove(z->dnssec_transactions, t); | |
96 | set_free(t->notify_transactions); | |
97 | ||
98 | while ((z = set_steal_first(t->dnssec_transactions))) { | |
99 | set_remove(z->notify_transactions, t); | |
100 | dns_transaction_gc(z); | |
101 | } | |
102 | set_free(t->dnssec_transactions); | |
103 | ||
104 | dns_answer_unref(t->validated_keys); | |
97cc656c | 105 | dns_resource_key_unref(t->key); |
a5784c49 | 106 | free(t->key_string); |
97cc656c | 107 | |
ec2c5e43 LP |
108 | free(t); |
109 | return NULL; | |
110 | } | |
111 | ||
112 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
113 | ||
51e399bc | 114 | bool dns_transaction_gc(DnsTransaction *t) { |
ec2c5e43 LP |
115 | assert(t); |
116 | ||
117 | if (t->block_gc > 0) | |
51e399bc | 118 | return true; |
ec2c5e43 | 119 | |
547973de LP |
120 | if (set_isempty(t->notify_query_candidates) && |
121 | set_isempty(t->notify_zone_items) && | |
51e399bc | 122 | set_isempty(t->notify_transactions)) { |
ec2c5e43 | 123 | dns_transaction_free(t); |
51e399bc LP |
124 | return false; |
125 | } | |
126 | ||
127 | return true; | |
ec2c5e43 LP |
128 | } |
129 | ||
f52e61da | 130 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { |
ec2c5e43 LP |
131 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; |
132 | int r; | |
133 | ||
134 | assert(ret); | |
135 | assert(s); | |
f52e61da | 136 | assert(key); |
ec2c5e43 | 137 | |
9eae2bf3 | 138 | /* Don't allow looking up invalid or pseudo RRs */ |
c463eb78 | 139 | if (!dns_type_is_valid_query(key->type)) |
9eae2bf3 LP |
140 | return -EINVAL; |
141 | ||
142 | /* We only support the IN class */ | |
c463eb78 | 143 | if (key->class != DNS_CLASS_IN && key->class != DNS_CLASS_ANY) |
9eae2bf3 LP |
144 | return -EOPNOTSUPP; |
145 | ||
d5099efc | 146 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
147 | if (r < 0) |
148 | return r; | |
149 | ||
f9ebb22a | 150 | r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); |
da0c630e LP |
151 | if (r < 0) |
152 | return r; | |
153 | ||
ec2c5e43 LP |
154 | t = new0(DnsTransaction, 1); |
155 | if (!t) | |
156 | return -ENOMEM; | |
157 | ||
4667e00a | 158 | t->dns_udp_fd = -1; |
c3bc53e6 | 159 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; |
019036a4 | 160 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
d3760be0 | 161 | t->answer_nsec_ttl = (uint32_t) -1; |
f52e61da | 162 | t->key = dns_resource_key_ref(key); |
ec2c5e43 | 163 | |
da0c630e | 164 | /* Find a fresh, unused transaction id */ |
ec2c5e43 LP |
165 | do |
166 | random_bytes(&t->id, sizeof(t->id)); | |
167 | while (t->id == 0 || | |
168 | hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(t->id))); | |
169 | ||
170 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
171 | if (r < 0) { | |
172 | t->id = 0; | |
173 | return r; | |
174 | } | |
175 | ||
f9ebb22a | 176 | r = hashmap_replace(s->transactions_by_key, t->key, t); |
da0c630e LP |
177 | if (r < 0) { |
178 | hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
179 | return r; | |
180 | } | |
181 | ||
f9ebb22a | 182 | LIST_PREPEND(transactions_by_scope, s->transactions, t); |
ec2c5e43 LP |
183 | t->scope = s; |
184 | ||
a150ff5e LP |
185 | s->manager->n_transactions_total ++; |
186 | ||
ec2c5e43 LP |
187 | if (ret) |
188 | *ret = t; | |
189 | ||
190 | t = NULL; | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
ec2c5e43 | 195 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { |
2fb3034c | 196 | _cleanup_free_ char *pretty = NULL; |
ec2c5e43 | 197 | DnsZoneItem *z; |
ec2c5e43 LP |
198 | |
199 | assert(t); | |
200 | assert(p); | |
201 | ||
202 | if (manager_our_packet(t->scope->manager, p) != 0) | |
203 | return; | |
204 | ||
2fb3034c LP |
205 | in_addr_to_string(p->family, &p->sender, &pretty); |
206 | ||
a5784c49 LP |
207 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", |
208 | t->id, | |
209 | dns_transaction_key_string(t), | |
ec2c5e43 LP |
210 | dns_protocol_to_string(t->scope->protocol), |
211 | t->scope->link ? t->scope->link->name : "*", | |
2fb3034c LP |
212 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), |
213 | pretty); | |
ec2c5e43 | 214 | |
a4076574 LP |
215 | /* RFC 4795, Section 4.1 says that the peer with the |
216 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
217 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
218 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
219 | return; |
220 | } | |
221 | ||
4d91eec4 | 222 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 223 | |
ec2c5e43 | 224 | t->block_gc++; |
547973de | 225 | while ((z = set_first(t->notify_zone_items))) { |
3ef64445 LP |
226 | /* First, make sure the zone item drops the reference |
227 | * to us */ | |
228 | dns_zone_item_probe_stop(z); | |
229 | ||
230 | /* Secondly, report this as conflict, so that we might | |
231 | * look for a different hostname */ | |
ec2c5e43 | 232 | dns_zone_item_conflict(z); |
3ef64445 | 233 | } |
ec2c5e43 LP |
234 | t->block_gc--; |
235 | ||
236 | dns_transaction_gc(t); | |
237 | } | |
238 | ||
239 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
801ad6a6 | 240 | DnsQueryCandidate *c; |
ec2c5e43 | 241 | DnsZoneItem *z; |
547973de | 242 | DnsTransaction *d; |
ec2c5e43 LP |
243 | Iterator i; |
244 | ||
245 | assert(t); | |
547973de | 246 | assert(!DNS_TRANSACTION_IS_LIVE(state)); |
e56187ca | 247 | |
f61dfddb LP |
248 | if (state == DNS_TRANSACTION_DNSSEC_FAILED) |
249 | log_struct(LOG_NOTICE, | |
beef6a5f | 250 | LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_FAILURE), |
f61dfddb LP |
251 | LOG_MESSAGE("DNSSEC validation failed for question %s: %s", dns_transaction_key_string(t), dnssec_result_to_string(t->answer_dnssec_result)), |
252 | "DNS_TRANSACTION=%" PRIu16, t->id, | |
253 | "DNS_QUESTION=%s", dns_transaction_key_string(t), | |
254 | "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), | |
255 | NULL); | |
256 | ||
ec2c5e43 LP |
257 | /* Note that this call might invalidate the query. Callers |
258 | * should hence not attempt to access the query or transaction | |
259 | * after calling this function. */ | |
260 | ||
a5784c49 LP |
261 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", |
262 | t->id, | |
263 | dns_transaction_key_string(t), | |
ec2c5e43 LP |
264 | dns_protocol_to_string(t->scope->protocol), |
265 | t->scope->link ? t->scope->link->name : "*", | |
266 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), | |
c3bc53e6 | 267 | dns_transaction_state_to_string(state), |
a5784c49 LP |
268 | t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), |
269 | t->answer_authenticated ? "authenticated" : "unsigned"); | |
ec2c5e43 LP |
270 | |
271 | t->state = state; | |
272 | ||
f32f0e57 | 273 | dns_transaction_close_connection(t); |
f535705a | 274 | dns_transaction_stop_timeout(t); |
ec2c5e43 LP |
275 | |
276 | /* Notify all queries that are interested, but make sure the | |
277 | * transaction isn't freed while we are still looking at it */ | |
278 | t->block_gc++; | |
f7014757 | 279 | |
547973de LP |
280 | SET_FOREACH(c, t->notify_query_candidates, i) |
281 | dns_query_candidate_notify(c); | |
282 | SET_FOREACH(z, t->notify_zone_items, i) | |
283 | dns_zone_item_notify(z); | |
ec2c5e43 | 284 | |
f7014757 LP |
285 | if (!set_isempty(t->notify_transactions)) { |
286 | DnsTransaction **nt; | |
287 | unsigned j, n = 0; | |
288 | ||
289 | /* We need to be careful when notifying other | |
290 | * transactions, as that might destroy other | |
291 | * transactions in our list. Hence, in order to be | |
292 | * able to safely iterate through the list of | |
293 | * transactions, take a GC lock on all of them | |
294 | * first. Then, in a second loop, notify them, but | |
295 | * first unlock that specific transaction. */ | |
296 | ||
297 | nt = newa(DnsTransaction*, set_size(t->notify_transactions)); | |
298 | SET_FOREACH(d, t->notify_transactions, i) { | |
299 | nt[n++] = d; | |
300 | d->block_gc++; | |
301 | } | |
302 | ||
303 | assert(n == set_size(t->notify_transactions)); | |
304 | ||
305 | for (j = 0; j < n; j++) { | |
306 | if (set_contains(t->notify_transactions, nt[j])) | |
307 | dns_transaction_notify(nt[j], t); | |
308 | ||
309 | nt[j]->block_gc--; | |
310 | dns_transaction_gc(nt[j]); | |
311 | } | |
312 | } | |
313 | ||
314 | t->block_gc--; | |
ec2c5e43 LP |
315 | dns_transaction_gc(t); |
316 | } | |
317 | ||
519ef046 LP |
318 | static int dns_transaction_pick_server(DnsTransaction *t) { |
319 | DnsServer *server; | |
320 | ||
321 | assert(t); | |
322 | assert(t->scope->protocol == DNS_PROTOCOL_DNS); | |
323 | ||
324 | server = dns_scope_get_dns_server(t->scope); | |
325 | if (!server) | |
326 | return -ESRCH; | |
327 | ||
f4461e56 | 328 | t->current_features = dns_server_possible_feature_level(server); |
519ef046 LP |
329 | |
330 | if (server == t->server) | |
331 | return 0; | |
332 | ||
333 | dns_server_unref(t->server); | |
334 | t->server = dns_server_ref(server); | |
335 | ||
336 | return 1; | |
337 | } | |
338 | ||
8d10d620 LP |
339 | static void dns_transaction_retry(DnsTransaction *t) { |
340 | int r; | |
341 | ||
342 | assert(t); | |
343 | ||
344 | log_debug("Retrying transaction %" PRIu16 ".", t->id); | |
345 | ||
346 | /* Before we try again, switch to a new server. */ | |
347 | dns_scope_next_dns_server(t->scope); | |
348 | ||
349 | r = dns_transaction_go(t); | |
350 | if (r < 0) | |
351 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
352 | } | |
353 | ||
ec2c5e43 LP |
354 | static int on_stream_complete(DnsStream *s, int error) { |
355 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
356 | DnsTransaction *t; | |
357 | ||
358 | assert(s); | |
359 | assert(s->transaction); | |
360 | ||
361 | /* Copy the data we care about out of the stream before we | |
362 | * destroy it. */ | |
363 | t = s->transaction; | |
364 | p = dns_packet_ref(s->read_packet); | |
365 | ||
366 | t->stream = dns_stream_free(t->stream); | |
367 | ||
a1a3f73a LP |
368 | if (ERRNO_IS_DISCONNECT(error)) { |
369 | usec_t usec; | |
370 | ||
92ec902a | 371 | log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); |
a1a3f73a | 372 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
6bb2c085 | 373 | dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_features, usec - t->start_usec); |
a1a3f73a LP |
374 | |
375 | dns_transaction_retry(t); | |
ac720200 LP |
376 | return 0; |
377 | } | |
ec2c5e43 LP |
378 | if (error != 0) { |
379 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
380 | return 0; | |
381 | } | |
382 | ||
a4076574 | 383 | if (dns_packet_validate_reply(p) <= 0) { |
a20b9592 | 384 | log_debug("Invalid TCP reply packet."); |
a4076574 LP |
385 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
386 | return 0; | |
387 | } | |
388 | ||
389 | dns_scope_check_conflicts(t->scope, p); | |
390 | ||
ec2c5e43 LP |
391 | t->block_gc++; |
392 | dns_transaction_process_reply(t, p); | |
393 | t->block_gc--; | |
394 | ||
519ef046 LP |
395 | /* If the response wasn't useful, then complete the transition |
396 | * now. After all, we are the worst feature set now with TCP | |
397 | * sockets, and there's really no point in retrying. */ | |
ec2c5e43 LP |
398 | if (t->state == DNS_TRANSACTION_PENDING) |
399 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
598f44bd LP |
400 | else |
401 | dns_transaction_gc(t); | |
ec2c5e43 LP |
402 | |
403 | return 0; | |
404 | } | |
405 | ||
406 | static int dns_transaction_open_tcp(DnsTransaction *t) { | |
407 | _cleanup_close_ int fd = -1; | |
408 | int r; | |
409 | ||
410 | assert(t); | |
411 | ||
519ef046 | 412 | dns_transaction_close_connection(t); |
ec2c5e43 | 413 | |
106784eb | 414 | switch (t->scope->protocol) { |
519ef046 | 415 | |
106784eb | 416 | case DNS_PROTOCOL_DNS: |
519ef046 LP |
417 | r = dns_transaction_pick_server(t); |
418 | if (r < 0) | |
419 | return r; | |
420 | ||
92ec902a | 421 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
422 | return -EOPNOTSUPP; |
423 | ||
519ef046 LP |
424 | r = dns_server_adjust_opt(t->server, t->sent, t->current_features); |
425 | if (r < 0) | |
426 | return r; | |
427 | ||
428 | fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, 53); | |
106784eb | 429 | break; |
ec2c5e43 | 430 | |
106784eb | 431 | case DNS_PROTOCOL_LLMNR: |
a8f6397f | 432 | /* When we already received a reply to this (but it was truncated), send to its sender address */ |
ec2c5e43 | 433 | if (t->received) |
519ef046 | 434 | fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port); |
ec2c5e43 LP |
435 | else { |
436 | union in_addr_union address; | |
a7f7d1bd | 437 | int family = AF_UNSPEC; |
ec2c5e43 LP |
438 | |
439 | /* Otherwise, try to talk to the owner of a | |
440 | * the IP address, in case this is a reverse | |
441 | * PTR lookup */ | |
f52e61da LP |
442 | |
443 | r = dns_name_address(DNS_RESOURCE_KEY_NAME(t->key), &family, &address); | |
ec2c5e43 LP |
444 | if (r < 0) |
445 | return r; | |
446 | if (r == 0) | |
447 | return -EINVAL; | |
9e08a6e0 | 448 | if (family != t->scope->family) |
9318cdd3 | 449 | return -ESRCH; |
ec2c5e43 | 450 | |
519ef046 | 451 | fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT); |
ec2c5e43 | 452 | } |
106784eb DM |
453 | |
454 | break; | |
455 | ||
456 | default: | |
ec2c5e43 | 457 | return -EAFNOSUPPORT; |
106784eb | 458 | } |
ec2c5e43 LP |
459 | |
460 | if (fd < 0) | |
461 | return fd; | |
462 | ||
463 | r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd); | |
464 | if (r < 0) | |
465 | return r; | |
ec2c5e43 LP |
466 | fd = -1; |
467 | ||
468 | r = dns_stream_write_packet(t->stream, t->sent); | |
469 | if (r < 0) { | |
470 | t->stream = dns_stream_free(t->stream); | |
471 | return r; | |
472 | } | |
473 | ||
ec2c5e43 LP |
474 | t->stream->complete = on_stream_complete; |
475 | t->stream->transaction = t; | |
476 | ||
477 | /* The interface index is difficult to determine if we are | |
478 | * connecting to the local host, hence fill this in right away | |
479 | * instead of determining it from the socket */ | |
480 | if (t->scope->link) | |
481 | t->stream->ifindex = t->scope->link->ifindex; | |
482 | ||
519ef046 LP |
483 | dns_transaction_reset_answer(t); |
484 | ||
cbe4216d LP |
485 | t->tried_stream = true; |
486 | ||
ec2c5e43 LP |
487 | return 0; |
488 | } | |
489 | ||
547973de | 490 | static void dns_transaction_cache_answer(DnsTransaction *t) { |
547973de LP |
491 | assert(t); |
492 | ||
493 | /* For mDNS we cache whenever we get the packet, rather than | |
494 | * in each transaction. */ | |
495 | if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) | |
496 | return; | |
497 | ||
498 | /* We never cache if this packet is from the local host, under | |
499 | * the assumption that a locally running DNS server would | |
500 | * cache this anyway, and probably knows better when to flush | |
501 | * the cache then we could. */ | |
502 | if (!DNS_PACKET_SHALL_CACHE(t->received)) | |
503 | return; | |
504 | ||
547973de LP |
505 | dns_cache_put(&t->scope->cache, |
506 | t->key, | |
507 | t->answer_rcode, | |
508 | t->answer, | |
547973de | 509 | t->answer_authenticated, |
d3760be0 | 510 | t->answer_nsec_ttl, |
547973de LP |
511 | 0, |
512 | t->received->family, | |
513 | &t->received->sender); | |
514 | } | |
515 | ||
105e1512 LP |
516 | static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { |
517 | DnsTransaction *dt; | |
518 | Iterator i; | |
519 | ||
520 | assert(t); | |
521 | ||
522 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
523 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
524 | return true; | |
525 | ||
526 | return false; | |
527 | } | |
528 | ||
547973de LP |
529 | static void dns_transaction_process_dnssec(DnsTransaction *t) { |
530 | int r; | |
531 | ||
532 | assert(t); | |
533 | ||
534 | /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ | |
105e1512 | 535 | if (dns_transaction_dnssec_is_live(t)) |
547973de LP |
536 | return; |
537 | ||
538 | /* All our auxiliary DNSSEC transactions are complete now. Try | |
539 | * to validate our RRset now. */ | |
540 | r = dns_transaction_validate_dnssec(t); | |
541 | if (r < 0) { | |
542 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
543 | return; | |
544 | } | |
545 | ||
b652d4a2 LP |
546 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && |
547 | t->scope->dnssec_mode == DNSSEC_YES) { | |
548 | /* We are not in automatic downgrade mode, and the | |
549 | * server is bad, refuse operation. */ | |
550 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
551 | return; | |
552 | } | |
553 | ||
019036a4 | 554 | if (!IN_SET(t->answer_dnssec_result, |
b652d4a2 LP |
555 | _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ |
556 | DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ | |
557 | DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ | |
558 | DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ | |
547973de LP |
559 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
560 | return; | |
561 | } | |
562 | ||
563 | dns_transaction_cache_answer(t); | |
564 | ||
565 | if (t->answer_rcode == DNS_RCODE_SUCCESS) | |
566 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
567 | else | |
3bbdc31d | 568 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
547973de LP |
569 | } |
570 | ||
ec2c5e43 | 571 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { |
9df3ba6c | 572 | usec_t ts; |
ec2c5e43 LP |
573 | int r; |
574 | ||
575 | assert(t); | |
576 | assert(p); | |
9df3ba6c TG |
577 | assert(t->scope); |
578 | assert(t->scope->manager); | |
ec2c5e43 | 579 | |
5a7e41a3 LP |
580 | if (t->state != DNS_TRANSACTION_PENDING) |
581 | return; | |
582 | ||
ec2c5e43 LP |
583 | /* Note that this call might invalidate the query. Callers |
584 | * should hence not attempt to access the query or transaction | |
585 | * after calling this function. */ | |
586 | ||
b5efcf29 LP |
587 | log_debug("Processing incoming packet on transaction %" PRIu16".", t->id); |
588 | ||
106784eb | 589 | switch (t->scope->protocol) { |
b5efcf29 | 590 | |
106784eb | 591 | case DNS_PROTOCOL_LLMNR: |
ec2c5e43 LP |
592 | assert(t->scope->link); |
593 | ||
594 | /* For LLMNR we will not accept any packets from other | |
595 | * interfaces */ | |
596 | ||
597 | if (p->ifindex != t->scope->link->ifindex) | |
598 | return; | |
599 | ||
600 | if (p->family != t->scope->family) | |
601 | return; | |
602 | ||
603 | /* Tentative packets are not full responses but still | |
604 | * useful for identifying uniqueness conflicts during | |
605 | * probing. */ | |
8b757a38 | 606 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
607 | dns_transaction_tentative(t, p); |
608 | return; | |
609 | } | |
106784eb DM |
610 | |
611 | break; | |
612 | ||
4e5bf5e1 DM |
613 | case DNS_PROTOCOL_MDNS: |
614 | assert(t->scope->link); | |
615 | ||
616 | /* For mDNS we will not accept any packets from other interfaces */ | |
617 | if (p->ifindex != t->scope->link->ifindex) | |
618 | return; | |
619 | ||
620 | if (p->family != t->scope->family) | |
621 | return; | |
622 | ||
623 | break; | |
624 | ||
106784eb | 625 | case DNS_PROTOCOL_DNS: |
8ad182a1 LP |
626 | /* Note that we do not need to verify the |
627 | * addresses/port numbers of incoming traffic, as we | |
628 | * invoked connect() on our UDP socket in which case | |
629 | * the kernel already does the needed verification for | |
630 | * us. */ | |
106784eb DM |
631 | break; |
632 | ||
633 | default: | |
9c56a6f3 | 634 | assert_not_reached("Invalid DNS protocol."); |
ec2c5e43 LP |
635 | } |
636 | ||
ec2c5e43 LP |
637 | if (t->received != p) { |
638 | dns_packet_unref(t->received); | |
639 | t->received = dns_packet_ref(p); | |
640 | } | |
641 | ||
c3bc53e6 LP |
642 | t->answer_source = DNS_TRANSACTION_NETWORK; |
643 | ||
ec2c5e43 LP |
644 | if (p->ipproto == IPPROTO_TCP) { |
645 | if (DNS_PACKET_TC(p)) { | |
646 | /* Truncated via TCP? Somebody must be fucking with us */ | |
647 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
648 | return; | |
649 | } | |
650 | ||
651 | if (DNS_PACKET_ID(p) != t->id) { | |
652 | /* Not the reply to our query? Somebody must be fucking with us */ | |
653 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
654 | return; | |
655 | } | |
656 | } | |
657 | ||
38a03f06 | 658 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
9df3ba6c TG |
659 | |
660 | switch (t->scope->protocol) { | |
8af5b883 | 661 | |
9df3ba6c TG |
662 | case DNS_PROTOCOL_DNS: |
663 | assert(t->server); | |
664 | ||
4e0b8b17 TG |
665 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { |
666 | ||
8af5b883 | 667 | /* Request failed, immediately try again with reduced features */ |
4e0b8b17 TG |
668 | log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
669 | ||
670 | dns_server_packet_failed(t->server, t->current_features); | |
8d10d620 | 671 | dns_transaction_retry(t); |
4e0b8b17 | 672 | return; |
6bb2c085 LP |
673 | } else if (DNS_PACKET_TC(p)) |
674 | dns_server_packet_truncated(t->server, t->current_features); | |
675 | else | |
676 | dns_server_packet_received(t->server, p->ipproto, t->current_features, ts - t->start_usec, p->size); | |
9df3ba6c TG |
677 | |
678 | break; | |
8af5b883 | 679 | |
9df3ba6c TG |
680 | case DNS_PROTOCOL_LLMNR: |
681 | case DNS_PROTOCOL_MDNS: | |
682 | dns_scope_packet_received(t->scope, ts - t->start_usec); | |
9df3ba6c | 683 | break; |
8af5b883 | 684 | |
9df3ba6c | 685 | default: |
8af5b883 | 686 | assert_not_reached("Invalid DNS protocol."); |
9df3ba6c TG |
687 | } |
688 | ||
ec2c5e43 | 689 | if (DNS_PACKET_TC(p)) { |
547493c5 DM |
690 | |
691 | /* Truncated packets for mDNS are not allowed. Give up immediately. */ | |
692 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) { | |
693 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
694 | return; | |
695 | } | |
696 | ||
f757cd85 LP |
697 | log_debug("Reply truncated, retrying via TCP."); |
698 | ||
ec2c5e43 LP |
699 | /* Response was truncated, let's try again with good old TCP */ |
700 | r = dns_transaction_open_tcp(t); | |
701 | if (r == -ESRCH) { | |
702 | /* No servers found? Damn! */ | |
703 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
704 | return; | |
705 | } | |
91adc4db LP |
706 | if (r == -EOPNOTSUPP) { |
707 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
708 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
709 | return; | |
710 | } | |
ec2c5e43 | 711 | if (r < 0) { |
8af5b883 | 712 | /* On LLMNR, if we cannot connect to the host, |
ec2c5e43 | 713 | * we immediately give up */ |
034e8031 | 714 | if (t->scope->protocol != DNS_PROTOCOL_DNS) { |
ec2c5e43 LP |
715 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); |
716 | return; | |
717 | } | |
718 | ||
719 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
8d10d620 | 720 | dns_transaction_retry(t); |
ec2c5e43 | 721 | } |
2a6658ef LP |
722 | |
723 | return; | |
ec2c5e43 LP |
724 | } |
725 | ||
8af5b883 | 726 | /* Parse message, if it isn't parsed yet. */ |
ec2c5e43 LP |
727 | r = dns_packet_extract(p); |
728 | if (r < 0) { | |
729 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
730 | return; | |
731 | } | |
732 | ||
b5efcf29 LP |
733 | if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) { |
734 | ||
547493c5 | 735 | /* Only consider responses with equivalent query section to the request */ |
8af5b883 LP |
736 | r = dns_packet_is_reply_for(p, t->key); |
737 | if (r < 0) { | |
738 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
739 | return; | |
740 | } | |
741 | if (r == 0) { | |
547493c5 DM |
742 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
743 | return; | |
744 | } | |
29815b6c | 745 | |
547493c5 DM |
746 | /* Install the answer as answer to the transaction */ |
747 | dns_answer_unref(t->answer); | |
748 | t->answer = dns_answer_ref(p->answer); | |
749 | t->answer_rcode = DNS_PACKET_RCODE(p); | |
919c2ae0 | 750 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
105e1512 | 751 | t->answer_authenticated = false; |
79e24931 | 752 | |
51e399bc LP |
753 | /* Block GC while starting requests for additional DNSSEC RRs */ |
754 | t->block_gc++; | |
547973de | 755 | r = dns_transaction_request_dnssec_keys(t); |
51e399bc LP |
756 | t->block_gc--; |
757 | ||
758 | /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ | |
759 | if (!dns_transaction_gc(t)) | |
760 | return; | |
761 | ||
762 | /* Requesting additional keys might have resulted in | |
763 | * this transaction to fail, since the auxiliary | |
764 | * request failed for some reason. If so, we are not | |
765 | * in pending state anymore, and we should exit | |
766 | * quickly. */ | |
767 | if (t->state != DNS_TRANSACTION_PENDING) | |
768 | return; | |
547973de LP |
769 | if (r < 0) { |
770 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
771 | return; | |
772 | } | |
773 | if (r > 0) { | |
774 | /* There are DNSSEC transactions pending now. Update the state accordingly. */ | |
775 | t->state = DNS_TRANSACTION_VALIDATING; | |
f535705a LP |
776 | dns_transaction_close_connection(t); |
777 | dns_transaction_stop_timeout(t); | |
547973de LP |
778 | return; |
779 | } | |
547493c5 | 780 | } |
ec2c5e43 | 781 | |
547973de | 782 | dns_transaction_process_dnssec(t); |
ec2c5e43 LP |
783 | } |
784 | ||
c19ffd9f TG |
785 | static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
786 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
787 | DnsTransaction *t = userdata; | |
788 | int r; | |
789 | ||
790 | assert(t); | |
791 | assert(t->scope); | |
792 | ||
793 | r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); | |
7e1851e3 LP |
794 | if (ERRNO_IS_DISCONNECT(-r)) { |
795 | usec_t usec; | |
c19ffd9f | 796 | |
7e1851e3 LP |
797 | /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next |
798 | * recvmsg(). Treat this like a lost packet. */ | |
799 | ||
92ec902a | 800 | log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); |
7e1851e3 | 801 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
6bb2c085 | 802 | dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_features, usec - t->start_usec); |
7e1851e3 LP |
803 | |
804 | dns_transaction_retry(t); | |
805 | return 0; | |
806 | } | |
807 | if (r < 0) { | |
808 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
809 | return 0; | |
810 | } | |
811 | ||
812 | r = dns_packet_validate_reply(p); | |
813 | if (r < 0) { | |
814 | log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); | |
815 | return 0; | |
816 | } | |
817 | if (r == 0) { | |
818 | log_debug("Received inappropriate DNS packet as response, ignoring: %m"); | |
819 | return 0; | |
820 | } | |
821 | ||
822 | if (DNS_PACKET_ID(p) != t->id) { | |
823 | log_debug("Received packet with incorrect transaction ID, ignoring: %m"); | |
824 | return 0; | |
825 | } | |
c19ffd9f | 826 | |
7e1851e3 | 827 | dns_transaction_process_reply(t, p); |
c19ffd9f TG |
828 | return 0; |
829 | } | |
830 | ||
49cce12d | 831 | static int dns_transaction_emit_udp(DnsTransaction *t) { |
c19ffd9f TG |
832 | int r; |
833 | ||
834 | assert(t); | |
c19ffd9f | 835 | |
519ef046 | 836 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { |
c19ffd9f | 837 | |
519ef046 | 838 | r = dns_transaction_pick_server(t); |
471d40d9 TG |
839 | if (r < 0) |
840 | return r; | |
c19ffd9f | 841 | |
519ef046 LP |
842 | if (t->current_features < DNS_SERVER_FEATURE_LEVEL_UDP) |
843 | return -EAGAIN; | |
844 | ||
92ec902a | 845 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
846 | return -EOPNOTSUPP; |
847 | ||
519ef046 LP |
848 | if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ |
849 | int fd; | |
850 | ||
851 | dns_transaction_close_connection(t); | |
c19ffd9f | 852 | |
519ef046 LP |
853 | fd = dns_scope_socket_udp(t->scope, t->server, 53); |
854 | if (fd < 0) | |
855 | return fd; | |
856 | ||
857 | r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); | |
858 | if (r < 0) { | |
859 | safe_close(fd); | |
860 | return r; | |
861 | } | |
862 | ||
aa4a9deb | 863 | (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); |
519ef046 LP |
864 | t->dns_udp_fd = fd; |
865 | } | |
866 | ||
867 | r = dns_server_adjust_opt(t->server, t->sent, t->current_features); | |
868 | if (r < 0) | |
869 | return r; | |
870 | } else | |
871 | dns_transaction_close_connection(t); | |
872 | ||
873 | r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); | |
471d40d9 TG |
874 | if (r < 0) |
875 | return r; | |
c19ffd9f | 876 | |
519ef046 | 877 | dns_transaction_reset_answer(t); |
be808ea0 | 878 | |
471d40d9 | 879 | return 0; |
c19ffd9f TG |
880 | } |
881 | ||
ec2c5e43 LP |
882 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { |
883 | DnsTransaction *t = userdata; | |
ec2c5e43 LP |
884 | |
885 | assert(s); | |
886 | assert(t); | |
887 | ||
ef7ce6df DM |
888 | if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { |
889 | /* Timeout reached? Increase the timeout for the server used */ | |
890 | switch (t->scope->protocol) { | |
49cce12d | 891 | |
ef7ce6df DM |
892 | case DNS_PROTOCOL_DNS: |
893 | assert(t->server); | |
6bb2c085 | 894 | dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_features, usec - t->start_usec); |
ef7ce6df | 895 | break; |
49cce12d | 896 | |
ef7ce6df DM |
897 | case DNS_PROTOCOL_LLMNR: |
898 | case DNS_PROTOCOL_MDNS: | |
899 | dns_scope_packet_lost(t->scope, usec - t->start_usec); | |
ef7ce6df | 900 | break; |
49cce12d | 901 | |
ef7ce6df DM |
902 | default: |
903 | assert_not_reached("Invalid DNS protocol."); | |
904 | } | |
905 | ||
906 | if (t->initial_jitter_scheduled) | |
907 | t->initial_jitter_elapsed = true; | |
be808ea0 TG |
908 | } |
909 | ||
423659ab LP |
910 | log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); |
911 | ||
8d10d620 | 912 | dns_transaction_retry(t); |
ec2c5e43 LP |
913 | return 0; |
914 | } | |
915 | ||
9df3ba6c TG |
916 | static usec_t transaction_get_resend_timeout(DnsTransaction *t) { |
917 | assert(t); | |
918 | assert(t->scope); | |
919 | ||
920 | switch (t->scope->protocol) { | |
49cce12d | 921 | |
9df3ba6c TG |
922 | case DNS_PROTOCOL_DNS: |
923 | assert(t->server); | |
9df3ba6c | 924 | return t->server->resend_timeout; |
49cce12d | 925 | |
9df3ba6c | 926 | case DNS_PROTOCOL_MDNS: |
11a27c2e DM |
927 | assert(t->n_attempts > 0); |
928 | return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; | |
49cce12d | 929 | |
11a27c2e | 930 | case DNS_PROTOCOL_LLMNR: |
9df3ba6c | 931 | return t->scope->resend_timeout; |
49cce12d | 932 | |
9df3ba6c TG |
933 | default: |
934 | assert_not_reached("Invalid DNS protocol."); | |
935 | } | |
936 | } | |
937 | ||
c842ff24 | 938 | static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { |
ec2c5e43 LP |
939 | int r; |
940 | ||
941 | assert(t); | |
942 | ||
f535705a | 943 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 944 | |
ec2c5e43 LP |
945 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { |
946 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
947 | return 0; | |
948 | } | |
949 | ||
cbe4216d | 950 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { |
ec2c5e43 LP |
951 | /* If we already tried via a stream, then we don't |
952 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
953 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
954 | return 0; | |
955 | } | |
956 | ||
957 | t->n_attempts++; | |
9df3ba6c | 958 | t->start_usec = ts; |
c61d2b44 LP |
959 | |
960 | dns_transaction_reset_answer(t); | |
ec2c5e43 | 961 | |
0d2cd476 LP |
962 | /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ |
963 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
8e54f5d9 | 964 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); |
0d2cd476 LP |
965 | if (r < 0) |
966 | return r; | |
967 | if (r > 0) { | |
968 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
969 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
931851e8 | 970 | t->answer_authenticated = true; |
0d2cd476 LP |
971 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
972 | return 0; | |
973 | } | |
b2b796b8 LP |
974 | |
975 | if (dns_name_is_root(DNS_RESOURCE_KEY_NAME(t->key)) && | |
976 | t->key->type == DNS_TYPE_DS) { | |
977 | ||
978 | /* Hmm, this is a request for the root DS? A | |
979 | * DS RR doesn't exist in the root zone, and | |
980 | * if our trust anchor didn't know it either, | |
981 | * this means we cannot do any DNSSEC logic | |
982 | * anymore. */ | |
983 | ||
1ed8c0fb | 984 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
b2b796b8 LP |
985 | /* We are in downgrade mode. In this |
986 | * case, synthesize an unsigned empty | |
987 | * response, so that the any lookup | |
988 | * depending on this one can continue | |
989 | * assuming there was no DS, and hence | |
990 | * the root zone was unsigned. */ | |
991 | ||
992 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
993 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
994 | t->answer_authenticated = false; | |
995 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
996 | } else | |
997 | /* If we are not in downgrade mode, | |
998 | * then fail the lookup, because we | |
999 | * cannot reasonably answer it. There | |
1000 | * might be DS RRs, but we don't know | |
1001 | * them, and the DNS server won't tell | |
1002 | * them to us (and even if it would, | |
1003 | * we couldn't validate it and trust | |
1004 | * it). */ | |
1005 | dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); | |
1006 | ||
1007 | return 0; | |
1008 | } | |
0d2cd476 LP |
1009 | } |
1010 | ||
1011 | /* Check the zone, but only if this transaction is not used | |
d746bb3e | 1012 | * for probing or verifying a zone item. */ |
547973de | 1013 | if (set_isempty(t->notify_zone_items)) { |
d746bb3e | 1014 | |
ae6a4bbf | 1015 | r = dns_zone_lookup(&t->scope->zone, t->key, &t->answer, NULL, NULL); |
d746bb3e LP |
1016 | if (r < 0) |
1017 | return r; | |
1018 | if (r > 0) { | |
ae6a4bbf | 1019 | t->answer_rcode = DNS_RCODE_SUCCESS; |
c3bc53e6 | 1020 | t->answer_source = DNS_TRANSACTION_ZONE; |
931851e8 | 1021 | t->answer_authenticated = true; |
d746bb3e LP |
1022 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1023 | return 0; | |
1024 | } | |
1025 | } | |
1026 | ||
4d926a69 LP |
1027 | /* Check the cache, but only if this transaction is not used |
1028 | * for probing or verifying a zone item. */ | |
547973de | 1029 | if (set_isempty(t->notify_zone_items)) { |
2c27fbca | 1030 | |
4d926a69 LP |
1031 | /* Before trying the cache, let's make sure we figured out a |
1032 | * server to use. Should this cause a change of server this | |
1033 | * might flush the cache. */ | |
1034 | dns_scope_get_dns_server(t->scope); | |
2c27fbca | 1035 | |
4d926a69 LP |
1036 | /* Let's then prune all outdated entries */ |
1037 | dns_cache_prune(&t->scope->cache); | |
1038 | ||
931851e8 | 1039 | r = dns_cache_lookup(&t->scope->cache, t->key, &t->answer_rcode, &t->answer, &t->answer_authenticated); |
4d926a69 LP |
1040 | if (r < 0) |
1041 | return r; | |
1042 | if (r > 0) { | |
c3bc53e6 | 1043 | t->answer_source = DNS_TRANSACTION_CACHE; |
ae6a4bbf | 1044 | if (t->answer_rcode == DNS_RCODE_SUCCESS) |
4d926a69 LP |
1045 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1046 | else | |
3bbdc31d | 1047 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
4d926a69 LP |
1048 | return 0; |
1049 | } | |
ec2c5e43 LP |
1050 | } |
1051 | ||
1effe965 DM |
1052 | return 1; |
1053 | } | |
1054 | ||
0afa57e2 DM |
1055 | static int dns_transaction_make_packet_mdns(DnsTransaction *t) { |
1056 | ||
1057 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
7778dfff | 1058 | bool add_known_answers = false; |
0afa57e2 DM |
1059 | DnsTransaction *other; |
1060 | unsigned qdcount; | |
1061 | usec_t ts; | |
1062 | int r; | |
1063 | ||
1064 | assert(t); | |
1065 | assert(t->scope->protocol == DNS_PROTOCOL_MDNS); | |
1066 | ||
e5abebab | 1067 | /* Discard any previously prepared packet, so we can start over and coalesce again */ |
0afa57e2 DM |
1068 | t->sent = dns_packet_unref(t->sent); |
1069 | ||
1070 | r = dns_packet_new_query(&p, t->scope->protocol, 0, false); | |
1071 | if (r < 0) | |
1072 | return r; | |
1073 | ||
1074 | r = dns_packet_append_key(p, t->key, NULL); | |
1075 | if (r < 0) | |
1076 | return r; | |
1077 | ||
1078 | qdcount = 1; | |
1079 | ||
7778dfff DM |
1080 | if (dns_key_is_shared(t->key)) |
1081 | add_known_answers = true; | |
1082 | ||
0afa57e2 DM |
1083 | /* |
1084 | * For mDNS, we want to coalesce as many open queries in pending transactions into one single | |
1085 | * query packet on the wire as possible. To achieve that, we iterate through all pending transactions | |
1086 | * in our current scope, and see whether their timing contraints allow them to be sent. | |
1087 | */ | |
1088 | ||
1089 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
1090 | ||
1091 | LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { | |
1092 | ||
1093 | /* Skip ourselves */ | |
1094 | if (other == t) | |
1095 | continue; | |
1096 | ||
1097 | if (other->state != DNS_TRANSACTION_PENDING) | |
1098 | continue; | |
1099 | ||
1100 | if (other->next_attempt_after > ts) | |
1101 | continue; | |
1102 | ||
1103 | if (qdcount >= UINT16_MAX) | |
1104 | break; | |
1105 | ||
1106 | r = dns_packet_append_key(p, other->key, NULL); | |
1107 | ||
1108 | /* | |
1109 | * If we can't stuff more questions into the packet, just give up. | |
1110 | * One of the 'other' transactions will fire later and take care of the rest. | |
1111 | */ | |
1112 | if (r == -EMSGSIZE) | |
1113 | break; | |
1114 | ||
1115 | if (r < 0) | |
1116 | return r; | |
1117 | ||
c842ff24 | 1118 | r = dns_transaction_prepare(other, ts); |
0afa57e2 DM |
1119 | if (r <= 0) |
1120 | continue; | |
1121 | ||
1122 | ts += transaction_get_resend_timeout(other); | |
1123 | ||
1124 | r = sd_event_add_time( | |
1125 | other->scope->manager->event, | |
1126 | &other->timeout_event_source, | |
1127 | clock_boottime_or_monotonic(), | |
1128 | ts, 0, | |
1129 | on_transaction_timeout, other); | |
1130 | if (r < 0) | |
1131 | return r; | |
1132 | ||
aa4a9deb LP |
1133 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1134 | ||
0afa57e2 DM |
1135 | other->state = DNS_TRANSACTION_PENDING; |
1136 | other->next_attempt_after = ts; | |
1137 | ||
1138 | qdcount ++; | |
7778dfff DM |
1139 | |
1140 | if (dns_key_is_shared(other->key)) | |
1141 | add_known_answers = true; | |
0afa57e2 DM |
1142 | } |
1143 | ||
1144 | DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); | |
0afa57e2 | 1145 | |
7778dfff DM |
1146 | /* Append known answer section if we're asking for any shared record */ |
1147 | if (add_known_answers) { | |
1148 | r = dns_cache_export_shared_to_packet(&t->scope->cache, p); | |
1149 | if (r < 0) | |
1150 | return r; | |
1151 | } | |
1152 | ||
0afa57e2 DM |
1153 | t->sent = p; |
1154 | p = NULL; | |
1155 | ||
1156 | return 0; | |
1157 | } | |
1158 | ||
1159 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
1160 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1161 | int r; | |
1162 | ||
1163 | assert(t); | |
1164 | ||
1165 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) | |
1166 | return dns_transaction_make_packet_mdns(t); | |
1167 | ||
1168 | if (t->sent) | |
1169 | return 0; | |
1170 | ||
b652d4a2 | 1171 | r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); |
0afa57e2 DM |
1172 | if (r < 0) |
1173 | return r; | |
1174 | ||
1175 | r = dns_scope_good_key(t->scope, t->key); | |
1176 | if (r < 0) | |
1177 | return r; | |
1178 | if (r == 0) | |
1179 | return -EDOM; | |
1180 | ||
1181 | r = dns_packet_append_key(p, t->key, NULL); | |
1182 | if (r < 0) | |
1183 | return r; | |
1184 | ||
1185 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
1186 | DNS_PACKET_HEADER(p)->id = t->id; | |
1187 | ||
1188 | t->sent = p; | |
1189 | p = NULL; | |
1190 | ||
1191 | return 0; | |
1192 | } | |
1193 | ||
1effe965 DM |
1194 | int dns_transaction_go(DnsTransaction *t) { |
1195 | usec_t ts; | |
1196 | int r; | |
1197 | ||
1198 | assert(t); | |
1199 | ||
1200 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
547973de | 1201 | |
c842ff24 | 1202 | r = dns_transaction_prepare(t, ts); |
1effe965 DM |
1203 | if (r <= 0) |
1204 | return r; | |
1205 | ||
a5784c49 LP |
1206 | log_debug("Excercising transaction %" PRIu16 " for <%s> on scope %s on %s/%s.", |
1207 | t->id, | |
1208 | dns_transaction_key_string(t), | |
1209 | dns_protocol_to_string(t->scope->protocol), | |
1210 | t->scope->link ? t->scope->link->name : "*", | |
1211 | t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family)); | |
1effe965 | 1212 | |
ef7ce6df | 1213 | if (!t->initial_jitter_scheduled && |
ea12bcc7 DM |
1214 | (t->scope->protocol == DNS_PROTOCOL_LLMNR || |
1215 | t->scope->protocol == DNS_PROTOCOL_MDNS)) { | |
1216 | usec_t jitter, accuracy; | |
6e068472 LP |
1217 | |
1218 | /* RFC 4795 Section 2.7 suggests all queries should be | |
1219 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
1220 | ||
ef7ce6df | 1221 | t->initial_jitter_scheduled = true; |
6e068472 LP |
1222 | |
1223 | random_bytes(&jitter, sizeof(jitter)); | |
ea12bcc7 DM |
1224 | |
1225 | switch (t->scope->protocol) { | |
519ef046 | 1226 | |
ea12bcc7 DM |
1227 | case DNS_PROTOCOL_LLMNR: |
1228 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
1229 | accuracy = LLMNR_JITTER_INTERVAL_USEC; | |
1230 | break; | |
519ef046 | 1231 | |
ea12bcc7 DM |
1232 | case DNS_PROTOCOL_MDNS: |
1233 | jitter %= MDNS_JITTER_RANGE_USEC; | |
1234 | jitter += MDNS_JITTER_MIN_USEC; | |
1235 | accuracy = MDNS_JITTER_RANGE_USEC; | |
1236 | break; | |
1237 | default: | |
1238 | assert_not_reached("bad protocol"); | |
1239 | } | |
6e068472 LP |
1240 | |
1241 | r = sd_event_add_time( | |
1242 | t->scope->manager->event, | |
1243 | &t->timeout_event_source, | |
1244 | clock_boottime_or_monotonic(), | |
ea12bcc7 | 1245 | ts + jitter, accuracy, |
6e068472 LP |
1246 | on_transaction_timeout, t); |
1247 | if (r < 0) | |
1248 | return r; | |
1249 | ||
aa4a9deb LP |
1250 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1251 | ||
6e068472 | 1252 | t->n_attempts = 0; |
a9da14e1 | 1253 | t->next_attempt_after = ts; |
6e068472 LP |
1254 | t->state = DNS_TRANSACTION_PENDING; |
1255 | ||
ea12bcc7 | 1256 | log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); |
6e068472 LP |
1257 | return 0; |
1258 | } | |
1259 | ||
ec2c5e43 LP |
1260 | /* Otherwise, we need to ask the network */ |
1261 | r = dns_transaction_make_packet(t); | |
1262 | if (r == -EDOM) { | |
1263 | /* Not the right request to make on this network? | |
1264 | * (i.e. an A request made on IPv6 or an AAAA request | |
1265 | * made on IPv4, on LLMNR or mDNS.) */ | |
1266 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1267 | return 0; | |
1268 | } | |
1269 | if (r < 0) | |
1270 | return r; | |
1271 | ||
1272 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
f52e61da LP |
1273 | (dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), "in-addr.arpa") > 0 || |
1274 | dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), "ip6.arpa") > 0)) { | |
ec2c5e43 LP |
1275 | |
1276 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
1277 | * always be made via TCP on LLMNR */ | |
1278 | r = dns_transaction_open_tcp(t); | |
1279 | } else { | |
be808ea0 TG |
1280 | /* Try via UDP, and if that fails due to large size or lack of |
1281 | * support try via TCP */ | |
49cce12d | 1282 | r = dns_transaction_emit_udp(t); |
29ab0552 LP |
1283 | if (r == -EMSGSIZE) |
1284 | log_debug("Sending query via TCP since it is too large."); | |
034e8031 LP |
1285 | if (r == -EAGAIN) |
1286 | log_debug("Sending query via TCP since server doesn't support UDP."); | |
be808ea0 | 1287 | if (r == -EMSGSIZE || r == -EAGAIN) |
ec2c5e43 LP |
1288 | r = dns_transaction_open_tcp(t); |
1289 | } | |
be808ea0 | 1290 | |
ec2c5e43 LP |
1291 | if (r == -ESRCH) { |
1292 | /* No servers to send this to? */ | |
1293 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1294 | return 0; | |
91adc4db LP |
1295 | } |
1296 | if (r == -EOPNOTSUPP) { | |
1297 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1298 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1299 | return 0; | |
1300 | } | |
1301 | if (r < 0) { | |
13b551ac LP |
1302 | if (t->scope->protocol != DNS_PROTOCOL_DNS) { |
1303 | dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); | |
1304 | return 0; | |
1305 | } | |
1306 | ||
ec2c5e43 | 1307 | /* Couldn't send? Try immediately again, with a new server */ |
519ef046 | 1308 | dns_scope_next_dns_server(t->scope); |
ec2c5e43 LP |
1309 | |
1310 | return dns_transaction_go(t); | |
1311 | } | |
1312 | ||
a9da14e1 DM |
1313 | ts += transaction_get_resend_timeout(t); |
1314 | ||
9a015429 LP |
1315 | r = sd_event_add_time( |
1316 | t->scope->manager->event, | |
1317 | &t->timeout_event_source, | |
1318 | clock_boottime_or_monotonic(), | |
a9da14e1 | 1319 | ts, 0, |
9a015429 | 1320 | on_transaction_timeout, t); |
ec2c5e43 LP |
1321 | if (r < 0) |
1322 | return r; | |
1323 | ||
aa4a9deb LP |
1324 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1325 | ||
ec2c5e43 | 1326 | t->state = DNS_TRANSACTION_PENDING; |
a9da14e1 DM |
1327 | t->next_attempt_after = ts; |
1328 | ||
ec2c5e43 LP |
1329 | return 1; |
1330 | } | |
1331 | ||
f2992dc1 LP |
1332 | static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { |
1333 | DnsTransaction *n; | |
1334 | Iterator i; | |
1335 | int r; | |
1336 | ||
1337 | assert(t); | |
1338 | assert(aux); | |
1339 | ||
1340 | /* Try to find cyclic dependencies between transaction objects */ | |
1341 | ||
1342 | if (t == aux) | |
1343 | return 1; | |
1344 | ||
3eb6aa00 | 1345 | SET_FOREACH(n, aux->dnssec_transactions, i) { |
f2992dc1 LP |
1346 | r = dns_transaction_find_cyclic(t, n); |
1347 | if (r != 0) | |
1348 | return r; | |
1349 | } | |
1350 | ||
3eb6aa00 | 1351 | return 0; |
f2992dc1 LP |
1352 | } |
1353 | ||
547973de LP |
1354 | static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { |
1355 | DnsTransaction *aux; | |
1356 | int r; | |
1357 | ||
1358 | assert(t); | |
1359 | assert(ret); | |
1360 | assert(key); | |
1361 | ||
1362 | aux = dns_scope_find_transaction(t->scope, key, true); | |
1363 | if (!aux) { | |
1364 | r = dns_transaction_new(&aux, t->scope, key); | |
1365 | if (r < 0) | |
1366 | return r; | |
1367 | } else { | |
1368 | if (set_contains(t->dnssec_transactions, aux)) { | |
1369 | *ret = aux; | |
1370 | return 0; | |
1371 | } | |
f2992dc1 LP |
1372 | |
1373 | r = dns_transaction_find_cyclic(t, aux); | |
1374 | if (r < 0) | |
1375 | return r; | |
1376 | if (r > 0) { | |
1377 | log_debug("Detected potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", | |
1378 | aux->id, | |
1379 | strna(dns_transaction_key_string(aux)), | |
1380 | t->id, | |
1381 | strna(dns_transaction_key_string(t))); | |
1382 | return -ELOOP; | |
1383 | } | |
547973de LP |
1384 | } |
1385 | ||
1386 | r = set_ensure_allocated(&t->dnssec_transactions, NULL); | |
1387 | if (r < 0) | |
1388 | goto gc; | |
1389 | ||
1390 | r = set_ensure_allocated(&aux->notify_transactions, NULL); | |
1391 | if (r < 0) | |
1392 | goto gc; | |
1393 | ||
1394 | r = set_put(t->dnssec_transactions, aux); | |
1395 | if (r < 0) | |
1396 | goto gc; | |
1397 | ||
1398 | r = set_put(aux->notify_transactions, t); | |
1399 | if (r < 0) { | |
1400 | (void) set_remove(t->dnssec_transactions, aux); | |
1401 | goto gc; | |
1402 | } | |
1403 | ||
1404 | *ret = aux; | |
1405 | return 1; | |
1406 | ||
1407 | gc: | |
1408 | dns_transaction_gc(aux); | |
1409 | return r; | |
1410 | } | |
1411 | ||
1412 | static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { | |
1413 | _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; | |
1414 | DnsTransaction *aux; | |
1415 | int r; | |
1416 | ||
1417 | assert(t); | |
1418 | assert(key); | |
1419 | ||
1420 | /* Try to get the data from the trust anchor */ | |
8e54f5d9 | 1421 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); |
547973de LP |
1422 | if (r < 0) |
1423 | return r; | |
1424 | if (r > 0) { | |
1425 | r = dns_answer_extend(&t->validated_keys, a); | |
1426 | if (r < 0) | |
1427 | return r; | |
1428 | ||
1429 | return 0; | |
1430 | } | |
1431 | ||
1432 | /* This didn't work, ask for it via the network/cache then. */ | |
1433 | r = dns_transaction_add_dnssec_transaction(t, key, &aux); | |
f2992dc1 LP |
1434 | if (r == -ELOOP) /* This would result in a cyclic dependency */ |
1435 | return 0; | |
547973de LP |
1436 | if (r < 0) |
1437 | return r; | |
1438 | ||
1439 | if (aux->state == DNS_TRANSACTION_NULL) { | |
1440 | r = dns_transaction_go(aux); | |
1441 | if (r < 0) | |
1442 | return r; | |
1443 | } | |
1444 | ||
f2992dc1 | 1445 | return 1; |
547973de LP |
1446 | } |
1447 | ||
105e1512 LP |
1448 | static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { |
1449 | int r; | |
1450 | ||
1451 | assert(t); | |
1452 | ||
1453 | /* Checks whether the answer is positive, i.e. either a direct | |
1454 | * answer to the question, or a CNAME/DNAME for it */ | |
1455 | ||
1456 | r = dns_answer_match_key(t->answer, t->key, flags); | |
1457 | if (r != 0) | |
1458 | return r; | |
1459 | ||
1460 | r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); | |
1461 | if (r != 0) | |
1462 | return r; | |
1463 | ||
1464 | return false; | |
1465 | } | |
1466 | ||
8a516214 LP |
1467 | static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { |
1468 | int r; | |
1469 | ||
1470 | assert(t); | |
1471 | ||
1472 | /* Check whether the specified name is in the the NTA | |
1473 | * database, either in the global one, or the link-local | |
1474 | * one. */ | |
1475 | ||
1476 | r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); | |
1477 | if (r != 0) | |
1478 | return r; | |
1479 | ||
1480 | if (!t->scope->link) | |
1481 | return 0; | |
1482 | ||
1483 | return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); | |
1484 | } | |
1485 | ||
105e1512 LP |
1486 | static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { |
1487 | int r; | |
1488 | ||
1489 | assert(t); | |
1490 | ||
1491 | /* Checks whether the answer is negative, and lacks NSEC/NSEC3 | |
1492 | * RRs to prove it */ | |
1493 | ||
1494 | r = dns_transaction_has_positive_answer(t, NULL); | |
1495 | if (r < 0) | |
1496 | return r; | |
1497 | if (r > 0) | |
1498 | return false; | |
1499 | ||
8e54f5d9 LP |
1500 | /* Is this key explicitly listed as a negative trust anchor? |
1501 | * If so, it's nothing we need to care about */ | |
8a516214 | 1502 | r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(t->key)); |
8e54f5d9 LP |
1503 | if (r < 0) |
1504 | return r; | |
1505 | if (r > 0) | |
1506 | return false; | |
1507 | ||
105e1512 LP |
1508 | /* The answer does not contain any RRs that match to the |
1509 | * question. If so, let's see if there are any NSEC/NSEC3 RRs | |
1510 | * included. If not, the answer is unsigned. */ | |
1511 | ||
1512 | r = dns_answer_contains_nsec_or_nsec3(t->answer); | |
1513 | if (r < 0) | |
1514 | return r; | |
1515 | if (r > 0) | |
1516 | return false; | |
1517 | ||
1518 | return true; | |
1519 | } | |
1520 | ||
1521 | static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { | |
1522 | int r; | |
1523 | ||
1524 | assert(t); | |
1525 | assert(rr); | |
1526 | ||
1527 | /* Check if the specified RR is the "primary" response, | |
1528 | * i.e. either matches the question precisely or is a | |
1529 | * CNAME/DNAME for it, or is any kind of NSEC/NSEC3 RR */ | |
1530 | ||
1531 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1532 | if (r != 0) | |
1533 | return r; | |
1534 | ||
1535 | r = dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); | |
1536 | if (r != 0) | |
1537 | return r; | |
1538 | ||
1539 | if (rr->key->type == DNS_TYPE_NSEC3) { | |
1540 | const char *p; | |
1541 | ||
1542 | p = DNS_RESOURCE_KEY_NAME(rr->key); | |
1543 | r = dns_name_parent(&p); | |
1544 | if (r < 0) | |
1545 | return r; | |
1546 | if (r > 0) { | |
1547 | r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), p); | |
1548 | if (r < 0) | |
1549 | return r; | |
1550 | if (r > 0) | |
1551 | return true; | |
1552 | } | |
1553 | } | |
1554 | ||
1555 | return rr->key->type == DNS_TYPE_NSEC; | |
1556 | } | |
1557 | ||
92ec902a LP |
1558 | static bool dns_transaction_dnssec_supported(DnsTransaction *t) { |
1559 | assert(t); | |
1560 | ||
1561 | /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon | |
1562 | * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ | |
1563 | ||
1564 | if (t->scope->protocol != DNS_PROTOCOL_DNS) | |
1565 | return false; | |
1566 | ||
1567 | /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well | |
1568 | * be supported, hence return true. */ | |
1569 | if (!t->server) | |
1570 | return true; | |
1571 | ||
1572 | if (t->current_features < DNS_SERVER_FEATURE_LEVEL_DO) | |
1573 | return false; | |
1574 | ||
1575 | return dns_server_dnssec_supported(t->server); | |
1576 | } | |
1577 | ||
1578 | static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { | |
1579 | DnsTransaction *dt; | |
1580 | Iterator i; | |
1581 | ||
1582 | assert(t); | |
1583 | ||
1584 | /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ | |
1585 | ||
1586 | if (!dns_transaction_dnssec_supported(t)) | |
1587 | return false; | |
1588 | ||
1589 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
1590 | if (!dns_transaction_dnssec_supported(dt)) | |
1591 | return false; | |
1592 | ||
1593 | return true; | |
1594 | } | |
1595 | ||
547973de LP |
1596 | int dns_transaction_request_dnssec_keys(DnsTransaction *t) { |
1597 | DnsResourceRecord *rr; | |
105e1512 | 1598 | |
547973de LP |
1599 | int r; |
1600 | ||
1601 | assert(t); | |
1602 | ||
105e1512 LP |
1603 | /* |
1604 | * Retrieve all auxiliary RRs for the answer we got, so that | |
1605 | * we can verify signatures or prove that RRs are rightfully | |
1606 | * unsigned. Specifically: | |
1607 | * | |
1608 | * - For RRSIG we get the matching DNSKEY | |
1609 | * - For DNSKEY we get the matching DS | |
1610 | * - For unsigned SOA/NS we get the matching DS | |
b63fca62 | 1611 | * - For unsigned CNAME/DNAME/DS we get the parent SOA RR |
105e1512 LP |
1612 | * - For other unsigned RRs we get the matching SOA RR |
1613 | * - For SOA/NS/DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR | |
1614 | * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR | |
1615 | */ | |
1616 | ||
b652d4a2 | 1617 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de | 1618 | return 0; |
92ec902a LP |
1619 | if (t->answer_source != DNS_TRANSACTION_NETWORK) |
1620 | return 0; /* We only need to validate stuff from the network */ | |
1621 | if (!dns_transaction_dnssec_supported(t)) | |
1622 | return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */ | |
b652d4a2 | 1623 | |
547973de LP |
1624 | DNS_ANSWER_FOREACH(rr, t->answer) { |
1625 | ||
105e1512 LP |
1626 | if (dns_type_is_pseudo(rr->key->type)) |
1627 | continue; | |
1628 | ||
8e54f5d9 | 1629 | /* If this RR is in the negative trust anchor, we don't need to validate it. */ |
8a516214 | 1630 | r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key)); |
8e54f5d9 LP |
1631 | if (r < 0) |
1632 | return r; | |
1633 | if (r > 0) | |
1634 | continue; | |
1635 | ||
547973de LP |
1636 | switch (rr->key->type) { |
1637 | ||
1638 | case DNS_TYPE_RRSIG: { | |
1639 | /* For each RRSIG we request the matching DNSKEY */ | |
1640 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; | |
1641 | ||
1642 | /* If this RRSIG is about a DNSKEY RR and the | |
1643 | * signer is the same as the owner, then we | |
1644 | * already have the DNSKEY, and we don't have | |
1645 | * to look for more. */ | |
1646 | if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { | |
1647 | r = dns_name_equal(rr->rrsig.signer, DNS_RESOURCE_KEY_NAME(rr->key)); | |
1648 | if (r < 0) | |
1649 | return r; | |
1650 | if (r > 0) | |
1651 | continue; | |
1652 | } | |
1653 | ||
105e1512 LP |
1654 | /* If the signer is not a parent of our |
1655 | * original query, then this is about an | |
1656 | * auxiliary RRset, but not anything we asked | |
1657 | * for. In this case we aren't interested, | |
1658 | * because we don't want to request additional | |
1659 | * RRs for stuff we didn't really ask for, and | |
1660 | * also to avoid request loops, where | |
1661 | * additional RRs from one transaction result | |
1662 | * in another transaction whose additonal RRs | |
1663 | * point back to the original transaction, and | |
1664 | * we deadlock. */ | |
1665 | r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), rr->rrsig.signer); | |
547973de LP |
1666 | if (r < 0) |
1667 | return r; | |
1668 | if (r == 0) | |
1669 | continue; | |
1670 | ||
1671 | dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); | |
1672 | if (!dnskey) | |
1673 | return -ENOMEM; | |
1674 | ||
105e1512 | 1675 | log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", t->id, DNS_RESOURCE_KEY_NAME(rr->key), rr->rrsig.key_tag); |
547973de LP |
1676 | r = dns_transaction_request_dnssec_rr(t, dnskey); |
1677 | if (r < 0) | |
1678 | return r; | |
1679 | break; | |
1680 | } | |
1681 | ||
1682 | case DNS_TYPE_DNSKEY: { | |
1683 | /* For each DNSKEY we request the matching DS */ | |
1684 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
1685 | ||
105e1512 LP |
1686 | /* If the DNSKEY we are looking at is not for |
1687 | * zone we are interested in, nor any of its | |
1688 | * parents, we aren't interested, and don't | |
1689 | * request it. After all, we don't want to end | |
1690 | * up in request loops, and want to keep | |
1691 | * additional traffic down. */ | |
1692 | ||
1693 | r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), DNS_RESOURCE_KEY_NAME(rr->key)); | |
1694 | if (r < 0) | |
1695 | return r; | |
1696 | if (r == 0) | |
1697 | continue; | |
1698 | ||
547973de LP |
1699 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, DNS_RESOURCE_KEY_NAME(rr->key)); |
1700 | if (!ds) | |
1701 | return -ENOMEM; | |
1702 | ||
0c857028 | 1703 | log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", t->id, DNS_RESOURCE_KEY_NAME(rr->key), dnssec_keytag(rr, false)); |
105e1512 LP |
1704 | r = dns_transaction_request_dnssec_rr(t, ds); |
1705 | if (r < 0) | |
1706 | return r; | |
547973de | 1707 | |
105e1512 LP |
1708 | break; |
1709 | } | |
1710 | ||
105e1512 LP |
1711 | case DNS_TYPE_SOA: |
1712 | case DNS_TYPE_NS: { | |
1713 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
1714 | ||
1715 | /* For an unsigned SOA or NS, try to acquire | |
1716 | * the matching DS RR, as we are at a zone cut | |
1717 | * then, and whether a DS exists tells us | |
1718 | * whether the zone is signed. Do so only if | |
1719 | * this RR matches our original question, | |
1720 | * however. */ | |
1721 | ||
1722 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1723 | if (r < 0) | |
1724 | return r; | |
1725 | if (r == 0) | |
1726 | continue; | |
1727 | ||
1728 | r = dnssec_has_rrsig(t->answer, rr->key); | |
1729 | if (r < 0) | |
1730 | return r; | |
1731 | if (r > 0) | |
1732 | continue; | |
1733 | ||
1734 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, DNS_RESOURCE_KEY_NAME(rr->key)); | |
1735 | if (!ds) | |
1736 | return -ENOMEM; | |
1737 | ||
1738 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key)); | |
547973de LP |
1739 | r = dns_transaction_request_dnssec_rr(t, ds); |
1740 | if (r < 0) | |
1741 | return r; | |
1742 | ||
1743 | break; | |
105e1512 LP |
1744 | } |
1745 | ||
b63fca62 | 1746 | case DNS_TYPE_DS: |
105e1512 LP |
1747 | case DNS_TYPE_CNAME: |
1748 | case DNS_TYPE_DNAME: { | |
1749 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
1750 | const char *name; | |
1751 | ||
1752 | /* CNAMEs and DNAMEs cannot be located at a | |
1753 | * zone apex, hence ask for the parent SOA for | |
1754 | * unsigned CNAME/DNAME RRs, maybe that's the | |
1755 | * apex. But do all that only if this is | |
1756 | * actually a response to our original | |
b63fca62 LP |
1757 | * question. |
1758 | * | |
1759 | * Similar for DS RRs, which are signed when | |
1760 | * the parent SOA is signed. */ | |
105e1512 LP |
1761 | |
1762 | r = dns_transaction_is_primary_response(t, rr); | |
1763 | if (r < 0) | |
1764 | return r; | |
1765 | if (r == 0) | |
1766 | continue; | |
1767 | ||
1768 | r = dnssec_has_rrsig(t->answer, rr->key); | |
1769 | if (r < 0) | |
1770 | return r; | |
1771 | if (r > 0) | |
1772 | continue; | |
1773 | ||
1774 | name = DNS_RESOURCE_KEY_NAME(rr->key); | |
1775 | r = dns_name_parent(&name); | |
1776 | if (r < 0) | |
1777 | return r; | |
1778 | if (r == 0) | |
1779 | continue; | |
1780 | ||
1781 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); | |
1782 | if (!soa) | |
1783 | return -ENOMEM; | |
1784 | ||
b63fca62 | 1785 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key)); |
105e1512 LP |
1786 | r = dns_transaction_request_dnssec_rr(t, soa); |
1787 | if (r < 0) | |
1788 | return r; | |
1789 | ||
1790 | break; | |
1791 | } | |
1792 | ||
1793 | default: { | |
1794 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
1795 | ||
b63fca62 LP |
1796 | /* For other unsigned RRsets (including |
1797 | * NSEC/NSEC3!), look for proof the zone is | |
1798 | * unsigned, by requesting the SOA RR of the | |
1799 | * zone. However, do so only if they are | |
1800 | * directly relevant to our original | |
105e1512 LP |
1801 | * question. */ |
1802 | ||
1803 | r = dns_transaction_is_primary_response(t, rr); | |
1804 | if (r < 0) | |
1805 | return r; | |
1806 | if (r == 0) | |
1807 | continue; | |
1808 | ||
1809 | r = dnssec_has_rrsig(t->answer, rr->key); | |
1810 | if (r < 0) | |
1811 | return r; | |
1812 | if (r > 0) | |
1813 | continue; | |
1814 | ||
1815 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, DNS_RESOURCE_KEY_NAME(rr->key)); | |
1816 | if (!soa) | |
1817 | return -ENOMEM; | |
1818 | ||
db5b0e92 | 1819 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", t->id, DNS_RESOURCE_KEY_NAME(rr->key), dns_resource_record_to_string(rr)); |
105e1512 LP |
1820 | r = dns_transaction_request_dnssec_rr(t, soa); |
1821 | if (r < 0) | |
1822 | return r; | |
1823 | break; | |
547973de LP |
1824 | }} |
1825 | } | |
1826 | ||
105e1512 LP |
1827 | /* Above, we requested everything necessary to validate what |
1828 | * we got. Now, let's request what we need to validate what we | |
1829 | * didn't get... */ | |
1830 | ||
1831 | r = dns_transaction_has_unsigned_negative_answer(t); | |
1832 | if (r < 0) | |
1833 | return r; | |
1834 | if (r > 0) { | |
1835 | const char *name; | |
1836 | ||
1837 | name = DNS_RESOURCE_KEY_NAME(t->key); | |
1838 | ||
1839 | /* If this was a SOA or NS request, then this | |
1840 | * indicates that we are not at a zone apex, hence ask | |
1841 | * the parent name instead. If this was a DS request, | |
1842 | * then it's signed when the parent zone is signed, | |
1843 | * hence ask the parent in that case, too. */ | |
1844 | ||
1845 | if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS, DNS_TYPE_DS)) { | |
1846 | r = dns_name_parent(&name); | |
1847 | if (r < 0) | |
1848 | return r; | |
1849 | if (r > 0) | |
1850 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS/DS response).", t->id, DNS_RESOURCE_KEY_NAME(t->key)); | |
1851 | else | |
1852 | name = NULL; | |
1853 | } else | |
1854 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", t->id, DNS_RESOURCE_KEY_NAME(t->key)); | |
1855 | ||
1856 | if (name) { | |
1857 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
1858 | ||
1859 | soa = dns_resource_key_new(t->key->class, DNS_TYPE_SOA, name); | |
1860 | if (!soa) | |
1861 | return -ENOMEM; | |
1862 | ||
1863 | r = dns_transaction_request_dnssec_rr(t, soa); | |
1864 | if (r < 0) | |
1865 | return r; | |
1866 | } | |
1867 | } | |
1868 | ||
1869 | return dns_transaction_dnssec_is_live(t); | |
547973de LP |
1870 | } |
1871 | ||
1872 | void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { | |
1873 | int r; | |
1874 | ||
1875 | assert(t); | |
547973de LP |
1876 | assert(source); |
1877 | ||
105e1512 LP |
1878 | if (!IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)) |
1879 | return; | |
1880 | ||
547973de | 1881 | /* Invoked whenever any of our auxiliary DNSSEC transactions |
105e1512 LP |
1882 | completed its work. We copy any RRs from that transaction |
1883 | over into our list of validated keys -- but only if the | |
1884 | answer is authenticated. | |
1885 | ||
1886 | Note that we fail our transaction if the auxiliary | |
1887 | transaction failed, except on NXDOMAIN. This is because | |
1888 | some broken DNS servers (Akamai...) will return NXDOMAIN | |
1889 | for empty non-terminals. */ | |
1890 | ||
6773896e | 1891 | switch (source->state) { |
547973de | 1892 | |
6773896e LP |
1893 | case DNS_TRANSACTION_DNSSEC_FAILED: |
1894 | ||
1895 | log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(source->answer_dnssec_result)); | |
1896 | t->answer_dnssec_result = source->answer_dnssec_result; /* Copy error code over */ | |
1897 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
1898 | break; | |
1899 | ||
1900 | case DNS_TRANSACTION_RCODE_FAILURE: | |
1901 | ||
1902 | if (source->answer_rcode != DNS_RCODE_NXDOMAIN) { | |
1903 | log_debug("Auxiliary DNSSEC RR query failed with rcode=%i.", source->answer_rcode); | |
105e1512 | 1904 | goto fail; |
547973de | 1905 | } |
547973de | 1906 | |
6773896e LP |
1907 | /* fall-through: NXDOMAIN is good enough for us */ |
1908 | ||
1909 | case DNS_TRANSACTION_SUCCESS: | |
1910 | if (source->answer_authenticated) { | |
1911 | r = dns_answer_extend(&t->validated_keys, source->answer); | |
1912 | if (r < 0) { | |
1913 | log_error_errno(r, "Failed to merge validated DNSSEC key data: %m"); | |
1914 | goto fail; | |
1915 | } | |
1916 | } | |
1917 | ||
1918 | /* If the state is still PENDING, we are still in the loop | |
1919 | * that adds further DNSSEC transactions, hence don't check if | |
1920 | * we are ready yet. If the state is VALIDATING however, we | |
1921 | * should check if we are complete now. */ | |
1922 | if (t->state == DNS_TRANSACTION_VALIDATING) | |
1923 | dns_transaction_process_dnssec(t); | |
1924 | break; | |
1925 | ||
1926 | default: | |
1927 | log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(source->state)); | |
1928 | goto fail; | |
1929 | } | |
105e1512 LP |
1930 | |
1931 | return; | |
1932 | ||
1933 | fail: | |
019036a4 | 1934 | t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; |
105e1512 | 1935 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
547973de LP |
1936 | } |
1937 | ||
105e1512 LP |
1938 | static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { |
1939 | DnsResourceRecord *rr; | |
1940 | int ifindex, r; | |
1941 | ||
1942 | assert(t); | |
1943 | ||
1944 | /* Add all DNSKEY RRs from the answer that are validated by DS | |
1945 | * RRs from the list of validated keys to the list of | |
1946 | * validated keys. */ | |
1947 | ||
1948 | DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { | |
1949 | ||
1950 | r = dnssec_verify_dnskey_search(rr, t->validated_keys); | |
1951 | if (r < 0) | |
1952 | return r; | |
1953 | if (r == 0) | |
1954 | continue; | |
1955 | ||
1956 | /* If so, the DNSKEY is validated too. */ | |
1957 | r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); | |
1958 | if (r < 0) | |
1959 | return r; | |
1960 | } | |
1961 | ||
1962 | return 0; | |
1963 | } | |
1964 | ||
1965 | static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { | |
56352fe9 LP |
1966 | int r; |
1967 | ||
1968 | assert(t); | |
1969 | assert(rr); | |
1970 | ||
105e1512 LP |
1971 | /* Checks if the RR we are looking for must be signed with an |
1972 | * RRSIG. This is used for positive responses. */ | |
24a5b982 | 1973 | |
b652d4a2 | 1974 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 1975 | return false; |
56352fe9 | 1976 | |
105e1512 LP |
1977 | if (dns_type_is_pseudo(rr->key->type)) |
1978 | return -EINVAL; | |
56352fe9 | 1979 | |
8a516214 | 1980 | r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key)); |
8e54f5d9 LP |
1981 | if (r < 0) |
1982 | return r; | |
1983 | if (r > 0) | |
1984 | return false; | |
1985 | ||
105e1512 | 1986 | switch (rr->key->type) { |
56352fe9 | 1987 | |
105e1512 LP |
1988 | case DNS_TYPE_RRSIG: |
1989 | /* RRSIGs are the signatures themselves, they need no signing. */ | |
1990 | return false; | |
1991 | ||
1992 | case DNS_TYPE_SOA: | |
1993 | case DNS_TYPE_NS: { | |
1994 | DnsTransaction *dt; | |
1995 | Iterator i; | |
1996 | ||
b63fca62 | 1997 | /* For SOA or NS RRs we look for a matching DS transaction */ |
105e1512 LP |
1998 | |
1999 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2000 | ||
2001 | if (dt->key->class != rr->key->class) | |
2002 | continue; | |
2003 | if (dt->key->type != DNS_TYPE_DS) | |
2004 | continue; | |
2005 | ||
2006 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), DNS_RESOURCE_KEY_NAME(rr->key)); | |
2007 | if (r < 0) | |
2008 | return r; | |
2009 | if (r == 0) | |
2010 | continue; | |
2011 | ||
2012 | /* We found a DS transactions for the SOA/NS | |
2013 | * RRs we are looking at. If it discovered signed DS | |
2014 | * RRs, then we need to be signed, too. */ | |
2015 | ||
097a2517 TA |
2016 | if (!dt->answer_authenticated) |
2017 | return false; | |
105e1512 | 2018 | |
097a2517 | 2019 | return dns_answer_match_key(dt->answer, dt->key, NULL); |
105e1512 LP |
2020 | } |
2021 | ||
2022 | /* We found nothing that proves this is safe to leave | |
2023 | * this unauthenticated, hence ask inist on | |
2024 | * authentication. */ | |
2025 | return true; | |
2026 | } | |
2027 | ||
b63fca62 | 2028 | case DNS_TYPE_DS: |
105e1512 LP |
2029 | case DNS_TYPE_CNAME: |
2030 | case DNS_TYPE_DNAME: { | |
2031 | const char *parent = NULL; | |
2032 | DnsTransaction *dt; | |
2033 | Iterator i; | |
2034 | ||
b63fca62 LP |
2035 | /* |
2036 | * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. | |
2037 | * | |
2038 | * DS RRs are signed if the parent is signed, hence also look at the parent SOA | |
2039 | */ | |
105e1512 LP |
2040 | |
2041 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2042 | ||
2043 | if (dt->key->class != rr->key->class) | |
2044 | continue; | |
2045 | if (dt->key->type != DNS_TYPE_SOA) | |
2046 | continue; | |
2047 | ||
2048 | if (!parent) { | |
2049 | parent = DNS_RESOURCE_KEY_NAME(rr->key); | |
2050 | r = dns_name_parent(&parent); | |
2051 | if (r < 0) | |
2052 | return r; | |
2053 | if (r == 0) { | |
b63fca62 LP |
2054 | if (rr->key->type == DNS_TYPE_DS) |
2055 | return true; | |
2056 | ||
105e1512 LP |
2057 | /* A CNAME/DNAME without a parent? That's sooo weird. */ |
2058 | log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); | |
2059 | return -EBADMSG; | |
2060 | } | |
2061 | } | |
2062 | ||
2063 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), parent); | |
2064 | if (r < 0) | |
2065 | return r; | |
2066 | if (r == 0) | |
2067 | continue; | |
2068 | ||
2069 | return t->answer_authenticated; | |
2070 | } | |
2071 | ||
2072 | return true; | |
2073 | } | |
2074 | ||
2075 | default: { | |
2076 | DnsTransaction *dt; | |
2077 | Iterator i; | |
2078 | ||
b63fca62 | 2079 | /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ |
105e1512 LP |
2080 | |
2081 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2082 | ||
2083 | if (dt->key->class != rr->key->class) | |
2084 | continue; | |
2085 | if (dt->key->type != DNS_TYPE_SOA) | |
2086 | continue; | |
2087 | ||
2088 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), DNS_RESOURCE_KEY_NAME(rr->key)); | |
2089 | if (r < 0) | |
2090 | return r; | |
2091 | if (r == 0) | |
2092 | continue; | |
2093 | ||
2094 | /* We found the transaction that was supposed to find | |
2095 | * the SOA RR for us. It was successful, but found no | |
2096 | * RR for us. This means we are not at a zone cut. In | |
2097 | * this case, we require authentication if the SOA | |
2098 | * lookup was authenticated too. */ | |
2099 | return t->answer_authenticated; | |
2100 | } | |
2101 | ||
2102 | return true; | |
2103 | }} | |
56352fe9 LP |
2104 | } |
2105 | ||
d33b6cf3 LP |
2106 | static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { |
2107 | DnsTransaction *dt; | |
2108 | const char *tld; | |
2109 | Iterator i; | |
2110 | int r; | |
2111 | ||
2112 | /* If DNSSEC downgrade mode is on, checks whether the | |
2113 | * specified RR is one level below a TLD we have proven not to | |
2114 | * exist. In such a case we assume that this is a private | |
2115 | * domain, and permit it. | |
2116 | * | |
2117 | * This detects cases like the Fritz!Box router networks. Each | |
2118 | * Fritz!Box router serves a private "fritz.box" zone, in the | |
2119 | * non-existing TLD "box". Requests for the "fritz.box" domain | |
2120 | * are served by the router itself, while requests for the | |
2121 | * "box" domain will result in NXDOMAIN. | |
2122 | * | |
2123 | * Note that this logic is unable to detect cases where a | |
2124 | * router serves a private DNS zone directly under | |
2125 | * non-existing TLD. In such a case we cannot detect whether | |
2126 | * the TLD is supposed to exist or not, as all requests we | |
2127 | * make for it will be answered by the router's zone, and not | |
2128 | * by the root zone. */ | |
2129 | ||
2130 | assert(t); | |
2131 | ||
2132 | if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) | |
2133 | return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ | |
2134 | ||
2135 | tld = DNS_RESOURCE_KEY_NAME(key); | |
2136 | r = dns_name_parent(&tld); | |
2137 | if (r < 0) | |
2138 | return r; | |
2139 | if (r == 0) | |
2140 | return false; /* Already the root domain */ | |
2141 | ||
2142 | if (!dns_name_is_single_label(tld)) | |
2143 | return false; | |
2144 | ||
2145 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2146 | ||
2147 | if (dt->key->class != key->class) | |
2148 | continue; | |
2149 | ||
2150 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), tld); | |
2151 | if (r < 0) | |
2152 | return r; | |
2153 | if (r == 0) | |
2154 | continue; | |
2155 | ||
2156 | /* We found an auxiliary lookup we did for the TLD. If | |
2157 | * that returned with NXDOMAIN, we know the TLD didn't | |
2158 | * exist, and hence this might be a private zone. */ | |
2159 | ||
2160 | return dt->answer_rcode == DNS_RCODE_NXDOMAIN; | |
2161 | } | |
2162 | ||
2163 | return false; | |
2164 | } | |
2165 | ||
105e1512 LP |
2166 | static int dns_transaction_requires_nsec(DnsTransaction *t) { |
2167 | DnsTransaction *dt; | |
2168 | const char *name; | |
2169 | Iterator i; | |
2170 | int r; | |
56352fe9 LP |
2171 | |
2172 | assert(t); | |
2173 | ||
105e1512 LP |
2174 | /* Checks if we need to insist on NSEC/NSEC3 RRs for proving |
2175 | * this negative reply */ | |
56352fe9 | 2176 | |
b652d4a2 | 2177 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2178 | return false; |
56352fe9 | 2179 | |
105e1512 LP |
2180 | if (dns_type_is_pseudo(t->key->type)) |
2181 | return -EINVAL; | |
2182 | ||
8a516214 | 2183 | r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(t->key)); |
8e54f5d9 LP |
2184 | if (r < 0) |
2185 | return r; | |
2186 | if (r > 0) | |
2187 | return false; | |
2188 | ||
d33b6cf3 LP |
2189 | r = dns_transaction_in_private_tld(t, t->key); |
2190 | if (r < 0) | |
2191 | return r; | |
2192 | if (r > 0) { | |
2193 | /* The lookup is from a TLD that is proven not to | |
2194 | * exist, and we are in downgrade mode, hence ignore | |
2195 | * that fact that we didn't get any NSEC RRs.*/ | |
2196 | ||
2197 | log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", dns_transaction_key_string(t)); | |
2198 | return false; | |
2199 | } | |
2200 | ||
105e1512 LP |
2201 | name = DNS_RESOURCE_KEY_NAME(t->key); |
2202 | ||
2203 | if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS, DNS_TYPE_DS)) { | |
2204 | ||
2205 | /* We got a negative reply for this SOA/NS lookup? If | |
2206 | * so, then we are not at a zone apex, and thus should | |
2207 | * look at the result of the parent SOA lookup. | |
2208 | * | |
2209 | * We got a negative reply for this DS lookup? DS RRs | |
2210 | * are signed when their parent zone is signed, hence | |
2211 | * also check the parent SOA in this case. */ | |
2212 | ||
2213 | r = dns_name_parent(&name); | |
56352fe9 LP |
2214 | if (r < 0) |
2215 | return r; | |
2216 | if (r == 0) | |
105e1512 LP |
2217 | return true; |
2218 | } | |
2219 | ||
2220 | /* For all other RRs we check the SOA on the same level to see | |
2221 | * if it's signed. */ | |
2222 | ||
2223 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2224 | ||
2225 | if (dt->key->class != t->key->class) | |
2226 | continue; | |
2227 | if (dt->key->type != DNS_TYPE_SOA) | |
56352fe9 LP |
2228 | continue; |
2229 | ||
105e1512 | 2230 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), name); |
56352fe9 LP |
2231 | if (r < 0) |
2232 | return r; | |
105e1512 LP |
2233 | if (r == 0) |
2234 | continue; | |
2235 | ||
2236 | return dt->answer_authenticated; | |
56352fe9 LP |
2237 | } |
2238 | ||
105e1512 LP |
2239 | /* If in doubt, require NSEC/NSEC3 */ |
2240 | return true; | |
56352fe9 LP |
2241 | } |
2242 | ||
94aa7071 LP |
2243 | static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { |
2244 | DnsResourceRecord *rrsig; | |
2245 | bool found = false; | |
2246 | int r; | |
2247 | ||
2248 | /* Checks whether any of the DNSKEYs used for the RRSIGs for | |
2249 | * the specified RRset is authenticated (i.e. has a matching | |
2250 | * DS RR). */ | |
2251 | ||
8a516214 | 2252 | r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key)); |
8e54f5d9 LP |
2253 | if (r < 0) |
2254 | return r; | |
2255 | if (r > 0) | |
2256 | return false; | |
2257 | ||
94aa7071 LP |
2258 | DNS_ANSWER_FOREACH(rrsig, t->answer) { |
2259 | DnsTransaction *dt; | |
2260 | Iterator i; | |
2261 | ||
2262 | r = dnssec_key_match_rrsig(rr->key, rrsig); | |
2263 | if (r < 0) | |
2264 | return r; | |
2265 | if (r == 0) | |
2266 | continue; | |
2267 | ||
2268 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2269 | ||
2270 | if (dt->key->class != rr->key->class) | |
2271 | continue; | |
2272 | ||
2273 | if (dt->key->type == DNS_TYPE_DNSKEY) { | |
2274 | ||
2275 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), rrsig->rrsig.signer); | |
2276 | if (r < 0) | |
2277 | return r; | |
2278 | if (r == 0) | |
2279 | continue; | |
2280 | ||
2281 | /* OK, we found an auxiliary DNSKEY | |
2282 | * lookup. If that lookup is | |
2283 | * authenticated, report this. */ | |
2284 | ||
2285 | if (dt->answer_authenticated) | |
2286 | return true; | |
2287 | ||
2288 | found = true; | |
2289 | ||
2290 | } else if (dt->key->type == DNS_TYPE_DS) { | |
2291 | ||
2292 | r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), rrsig->rrsig.signer); | |
2293 | if (r < 0) | |
2294 | return r; | |
2295 | if (r == 0) | |
2296 | continue; | |
2297 | ||
2298 | /* OK, we found an auxiliary DS | |
2299 | * lookup. If that lookup is | |
2300 | * authenticated and non-zero, we | |
2301 | * won! */ | |
2302 | ||
2303 | if (!dt->answer_authenticated) | |
2304 | return false; | |
2305 | ||
2306 | return dns_answer_match_key(dt->answer, dt->key, NULL); | |
2307 | } | |
2308 | } | |
2309 | } | |
2310 | ||
2311 | return found ? false : -ENXIO; | |
2312 | } | |
2313 | ||
b652d4a2 LP |
2314 | static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { |
2315 | assert(t); | |
2316 | assert(rr); | |
2317 | ||
2318 | /* We know that the root domain is signed, hence if it appears | |
2319 | * not to be signed, there's a problem with the DNS server */ | |
2320 | ||
2321 | return rr->key->class == DNS_CLASS_IN && | |
2322 | dns_name_is_root(DNS_RESOURCE_KEY_NAME(rr->key)); | |
2323 | } | |
2324 | ||
0f87f3e8 LP |
2325 | static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { |
2326 | DnsResourceRecord *rr; | |
2327 | int r; | |
2328 | ||
2329 | assert(t); | |
2330 | ||
2331 | /* Maybe warn the user that we encountered a revoked DNSKEY | |
2332 | * for a key from our trust anchor. Note that we don't care | |
2333 | * whether the DNSKEY can be authenticated or not. It's | |
2334 | * sufficient if it is self-signed. */ | |
2335 | ||
2336 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
d424da2a | 2337 | r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); |
0f87f3e8 LP |
2338 | if (r < 0) |
2339 | return r; | |
2340 | } | |
2341 | ||
2342 | return 0; | |
2343 | } | |
2344 | ||
c9c72065 LP |
2345 | static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { |
2346 | bool changed; | |
2347 | int r; | |
2348 | ||
2349 | assert(t); | |
2350 | ||
2351 | /* Removes all DNSKEY/DS objects from t->validated_keys that | |
2352 | * our trust anchors database considers revoked. */ | |
2353 | ||
2354 | do { | |
2355 | DnsResourceRecord *rr; | |
2356 | ||
2357 | changed = false; | |
2358 | ||
2359 | DNS_ANSWER_FOREACH(rr, t->validated_keys) { | |
2360 | r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); | |
2361 | if (r < 0) | |
2362 | return r; | |
2363 | if (r > 0) { | |
2364 | r = dns_answer_remove_by_rr(&t->validated_keys, rr); | |
2365 | if (r < 0) | |
2366 | return r; | |
2367 | ||
2368 | assert(r > 0); | |
2369 | changed = true; | |
2370 | break; | |
2371 | } | |
2372 | } | |
2373 | } while (changed); | |
2374 | ||
2375 | return 0; | |
2376 | } | |
2377 | ||
547973de LP |
2378 | int dns_transaction_validate_dnssec(DnsTransaction *t) { |
2379 | _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; | |
0c7bff0a LP |
2380 | enum { |
2381 | PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ | |
2382 | PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ | |
2383 | PHASE_ALL, /* Phase #3, validate everything else */ | |
2384 | } phase; | |
547973de | 2385 | DnsResourceRecord *rr; |
105e1512 | 2386 | DnsAnswerFlags flags; |
56352fe9 | 2387 | int r; |
547973de LP |
2388 | |
2389 | assert(t); | |
2390 | ||
2391 | /* We have now collected all DS and DNSKEY RRs in | |
2392 | * t->validated_keys, let's see which RRs we can now | |
2393 | * authenticate with that. */ | |
2394 | ||
b652d4a2 | 2395 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de LP |
2396 | return 0; |
2397 | ||
2398 | /* Already validated */ | |
019036a4 | 2399 | if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) |
547973de LP |
2400 | return 0; |
2401 | ||
105e1512 | 2402 | /* Our own stuff needs no validation */ |
547973de | 2403 | if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { |
019036a4 | 2404 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
547973de LP |
2405 | t->answer_authenticated = true; |
2406 | return 0; | |
2407 | } | |
2408 | ||
105e1512 LP |
2409 | /* Cached stuff is not affected by validation. */ |
2410 | if (t->answer_source != DNS_TRANSACTION_NETWORK) | |
2411 | return 0; | |
2412 | ||
92ec902a | 2413 | if (!dns_transaction_dnssec_supported_full(t)) { |
b652d4a2 LP |
2414 | /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ |
2415 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
92ec902a | 2416 | log_debug("Cannot validate response, server lacks DNSSEC support."); |
b652d4a2 LP |
2417 | return 0; |
2418 | } | |
2419 | ||
a5784c49 | 2420 | log_debug("Validating response from transaction %" PRIu16 " (%s).", t->id, dns_transaction_key_string(t)); |
547973de | 2421 | |
c9c72065 LP |
2422 | /* First, see if this response contains any revoked trust |
2423 | * anchors we care about */ | |
0f87f3e8 LP |
2424 | r = dns_transaction_check_revoked_trust_anchors(t); |
2425 | if (r < 0) | |
2426 | return r; | |
2427 | ||
c9c72065 LP |
2428 | /* Second, see if there are DNSKEYs we already know a |
2429 | * validated DS for. */ | |
56352fe9 LP |
2430 | r = dns_transaction_validate_dnskey_by_ds(t); |
2431 | if (r < 0) | |
2432 | return r; | |
547973de | 2433 | |
c9c72065 LP |
2434 | /* Third, remove all DNSKEY and DS RRs again that our trust |
2435 | * anchor says are revoked. After all we might have marked | |
2436 | * some keys revoked above, but they might still be lingering | |
2437 | * in our validated_keys list. */ | |
2438 | r = dns_transaction_invalidate_revoked_keys(t); | |
2439 | if (r < 0) | |
2440 | return r; | |
2441 | ||
0c7bff0a | 2442 | phase = PHASE_DNSKEY; |
547973de | 2443 | for (;;) { |
0c7bff0a | 2444 | bool changed = false, have_nsec = false; |
547973de LP |
2445 | |
2446 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
0c7bff0a | 2447 | DnsResourceRecord *rrsig = NULL; |
547973de LP |
2448 | DnssecResult result; |
2449 | ||
0c7bff0a LP |
2450 | switch (rr->key->type) { |
2451 | ||
2452 | case DNS_TYPE_RRSIG: | |
547973de LP |
2453 | continue; |
2454 | ||
0c7bff0a LP |
2455 | case DNS_TYPE_DNSKEY: |
2456 | /* We validate DNSKEYs only in the DNSKEY and ALL phases */ | |
2457 | if (phase == PHASE_NSEC) | |
2458 | continue; | |
2459 | break; | |
2460 | ||
2461 | case DNS_TYPE_NSEC: | |
2462 | case DNS_TYPE_NSEC3: | |
2463 | have_nsec = true; | |
2464 | ||
2465 | /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ | |
2466 | if (phase == PHASE_DNSKEY) | |
2467 | continue; | |
2468 | ||
2469 | break; | |
2470 | ||
2471 | default: | |
2472 | /* We validate all other RRs only in the ALL phases */ | |
2473 | if (phase != PHASE_ALL) | |
2474 | continue; | |
2475 | ||
2476 | break; | |
2477 | } | |
2478 | ||
2479 | r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); | |
547973de LP |
2480 | if (r < 0) |
2481 | return r; | |
2482 | ||
7b50eb2e | 2483 | log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); |
547973de | 2484 | |
56352fe9 | 2485 | if (result == DNSSEC_VALIDATED) { |
547973de | 2486 | |
547973de LP |
2487 | if (rr->key->type == DNS_TYPE_DNSKEY) { |
2488 | /* If we just validated a | |
2489 | * DNSKEY RRset, then let's | |
2490 | * add these keys to the set | |
2491 | * of validated keys for this | |
2492 | * transaction. */ | |
2493 | ||
105e1512 | 2494 | r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); |
547973de LP |
2495 | if (r < 0) |
2496 | return r; | |
c9c72065 LP |
2497 | |
2498 | /* some of the DNSKEYs we just | |
2499 | * added might already have | |
2500 | * been revoked, remove them | |
2501 | * again in that case. */ | |
2502 | r = dns_transaction_invalidate_revoked_keys(t); | |
2503 | if (r < 0) | |
2504 | return r; | |
547973de LP |
2505 | } |
2506 | ||
105e1512 LP |
2507 | /* Add the validated RRset to the new |
2508 | * list of validated RRsets, and | |
2509 | * remove it from the unvalidated | |
2510 | * RRsets. We mark the RRset as | |
2511 | * authenticated and cacheable. */ | |
2512 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); | |
547973de LP |
2513 | if (r < 0) |
2514 | return r; | |
2515 | ||
a150ff5e LP |
2516 | t->scope->manager->n_dnssec_secure++; |
2517 | ||
56352fe9 | 2518 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
547973de LP |
2519 | changed = true; |
2520 | break; | |
f3cf586d | 2521 | } |
547973de | 2522 | |
0c7bff0a LP |
2523 | /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as |
2524 | * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, we | |
2525 | * cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ | |
2526 | if (phase != PHASE_ALL) | |
f3cf586d | 2527 | continue; |
b652d4a2 | 2528 | |
0c7bff0a LP |
2529 | if (result == DNSSEC_VALIDATED_WILDCARD) { |
2530 | bool authenticated = false; | |
2531 | const char *suffix; | |
2532 | ||
2533 | /* This RRset validated, but as a wildcard. This means we need to proof via NSEC/NSEC3 | |
2534 | * that no matching non-wildcard RR exists. | |
2535 | * | |
2536 | * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4*/ | |
2537 | ||
2538 | r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &suffix); | |
2539 | if (r < 0) | |
2540 | return r; | |
2541 | if (r == 0) | |
2542 | return -EBADMSG; | |
2543 | ||
2544 | r = dns_name_parent(&suffix); | |
2545 | if (r < 0) | |
2546 | return r; | |
2547 | if (r == 0) | |
2548 | return -EBADMSG; | |
2549 | ||
2550 | r = dnssec_nsec_test_between(validated, DNS_RESOURCE_KEY_NAME(rr->key), suffix, &authenticated); | |
2551 | if (r < 0) | |
2552 | return r; | |
2553 | ||
2554 | /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ | |
372dd764 | 2555 | if (r == 0) |
0c7bff0a | 2556 | result = DNSSEC_INVALID; |
372dd764 LP |
2557 | else { |
2558 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); | |
2559 | if (r < 0) | |
2560 | return r; | |
0c7bff0a | 2561 | |
372dd764 LP |
2562 | if (authenticated) |
2563 | t->scope->manager->n_dnssec_secure++; | |
2564 | else | |
2565 | t->scope->manager->n_dnssec_insecure++; | |
0c7bff0a | 2566 | |
372dd764 LP |
2567 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
2568 | changed = true; | |
2569 | break; | |
2570 | } | |
0c7bff0a LP |
2571 | } |
2572 | ||
f3cf586d LP |
2573 | if (result == DNSSEC_NO_SIGNATURE) { |
2574 | r = dns_transaction_requires_rrsig(t, rr); | |
2575 | if (r < 0) | |
2576 | return r; | |
2577 | if (r == 0) { | |
2578 | /* Data does not require signing. In that case, just copy it over, | |
2579 | * but remember that this is by no means authenticated.*/ | |
2580 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0); | |
b652d4a2 LP |
2581 | if (r < 0) |
2582 | return r; | |
b652d4a2 | 2583 | |
f3cf586d LP |
2584 | t->scope->manager->n_dnssec_insecure++; |
2585 | changed = true; | |
2586 | break; | |
2587 | } | |
b652d4a2 | 2588 | |
f3cf586d LP |
2589 | r = dns_transaction_known_signed(t, rr); |
2590 | if (r < 0) | |
2591 | return r; | |
2592 | if (r > 0) { | |
2593 | /* This is an RR we know has to be signed. If it isn't this means | |
2594 | * the server is not attaching RRSIGs, hence complain. */ | |
d33b6cf3 | 2595 | |
f3cf586d | 2596 | dns_server_packet_rrsig_missing(t->server); |
d33b6cf3 | 2597 | |
f3cf586d | 2598 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
d33b6cf3 | 2599 | |
f3cf586d | 2600 | /* Downgrading is OK? If so, just consider the information unsigned */ |
d33b6cf3 LP |
2601 | |
2602 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0); | |
2603 | if (r < 0) | |
2604 | return r; | |
2605 | ||
2606 | t->scope->manager->n_dnssec_insecure++; | |
2607 | changed = true; | |
2608 | break; | |
2609 | } | |
f3cf586d LP |
2610 | |
2611 | /* Otherwise, fail */ | |
2612 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
2613 | return 0; | |
94aa7071 LP |
2614 | } |
2615 | ||
f3cf586d LP |
2616 | r = dns_transaction_in_private_tld(t, rr->key); |
2617 | if (r < 0) | |
2618 | return r; | |
2619 | if (r > 0) { | |
2620 | _cleanup_free_ char *s = NULL; | |
94aa7071 | 2621 | |
f3cf586d LP |
2622 | /* The data is from a TLD that is proven not to exist, and we are in downgrade |
2623 | * mode, hence ignore the fact that this was not signed. */ | |
94aa7071 | 2624 | |
f3cf586d LP |
2625 | (void) dns_resource_key_to_string(rr->key, &s); |
2626 | log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", strna(s ? strstrip(s) : NULL)); | |
94aa7071 | 2627 | |
f3cf586d LP |
2628 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0); |
2629 | if (r < 0) | |
2630 | return r; | |
a150ff5e | 2631 | |
f3cf586d LP |
2632 | t->scope->manager->n_dnssec_insecure++; |
2633 | changed = true; | |
2634 | break; | |
105e1512 | 2635 | } |
f3cf586d | 2636 | } |
105e1512 | 2637 | |
f3cf586d LP |
2638 | if (IN_SET(result, |
2639 | DNSSEC_MISSING_KEY, | |
2640 | DNSSEC_SIGNATURE_EXPIRED, | |
2641 | DNSSEC_UNSUPPORTED_ALGORITHM)) { | |
a150ff5e | 2642 | |
f3cf586d LP |
2643 | r = dns_transaction_dnskey_authenticated(t, rr); |
2644 | if (r < 0 && r != -ENXIO) | |
547973de | 2645 | return r; |
f3cf586d LP |
2646 | if (r == 0) { |
2647 | /* The DNSKEY transaction was not authenticated, this means there's | |
2648 | * no DS for this, which means it's OK if no keys are found for this signature. */ | |
2649 | ||
2650 | r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0); | |
2651 | if (r < 0) | |
2652 | return r; | |
2653 | ||
2654 | t->scope->manager->n_dnssec_insecure++; | |
2655 | changed = true; | |
2656 | break; | |
547973de | 2657 | } |
f3cf586d | 2658 | } |
547973de | 2659 | |
f3cf586d LP |
2660 | if (IN_SET(result, |
2661 | DNSSEC_INVALID, | |
2662 | DNSSEC_SIGNATURE_EXPIRED, | |
2663 | DNSSEC_NO_SIGNATURE)) | |
2664 | t->scope->manager->n_dnssec_bogus++; | |
2665 | else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ | |
2666 | t->scope->manager->n_dnssec_indeterminate++; | |
547973de | 2667 | |
f3cf586d LP |
2668 | r = dns_transaction_is_primary_response(t, rr); |
2669 | if (r < 0) | |
2670 | return r; | |
2671 | if (r > 0) { | |
2672 | /* This is a primary response | |
2673 | * to our question, and it | |
2674 | * failed validation. That's | |
2675 | * fatal. */ | |
2676 | t->answer_dnssec_result = result; | |
2677 | return 0; | |
547973de | 2678 | } |
f3cf586d LP |
2679 | |
2680 | /* This is just some auxiliary | |
2681 | * data. Just remove the RRset and | |
2682 | * continue. */ | |
2683 | r = dns_answer_remove_by_key(&t->answer, rr->key); | |
2684 | if (r < 0) | |
2685 | return r; | |
2686 | ||
2687 | /* Exit the loop, we dropped something from the answer, start from the beginning */ | |
2688 | changed = true; | |
2689 | break; | |
547973de LP |
2690 | } |
2691 | ||
0c7bff0a | 2692 | /* Restart the inner loop as long as we managed to achieve something */ |
547973de LP |
2693 | if (changed) |
2694 | continue; | |
2695 | ||
0c7bff0a LP |
2696 | if (phase == PHASE_DNSKEY && have_nsec) { |
2697 | /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ | |
2698 | phase = PHASE_NSEC; | |
2699 | continue; | |
2700 | } | |
2701 | ||
2702 | if (phase != PHASE_ALL) { | |
2703 | /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. Note that in this | |
2704 | * third phase we start to remove RRs we couldn't validate. */ | |
2705 | phase = PHASE_ALL; | |
56352fe9 | 2706 | continue; |
547973de LP |
2707 | } |
2708 | ||
56352fe9 | 2709 | /* We're done */ |
547973de LP |
2710 | break; |
2711 | } | |
2712 | ||
2713 | dns_answer_unref(t->answer); | |
2714 | t->answer = validated; | |
2715 | validated = NULL; | |
2716 | ||
72667f08 LP |
2717 | /* At this point the answer only contains validated |
2718 | * RRsets. Now, let's see if it actually answers the question | |
2719 | * we asked. If so, great! If it doesn't, then see if | |
2720 | * NSEC/NSEC3 can prove this. */ | |
105e1512 | 2721 | r = dns_transaction_has_positive_answer(t, &flags); |
72667f08 | 2722 | if (r > 0) { |
105e1512 LP |
2723 | /* Yes, it answers the question! */ |
2724 | ||
2725 | if (flags & DNS_ANSWER_AUTHENTICATED) { | |
2726 | /* The answer is fully authenticated, yay. */ | |
019036a4 | 2727 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
105e1512 LP |
2728 | t->answer_rcode = DNS_RCODE_SUCCESS; |
2729 | t->answer_authenticated = true; | |
2730 | } else { | |
2731 | /* The answer is not fully authenticated. */ | |
019036a4 | 2732 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
2733 | t->answer_authenticated = false; |
2734 | } | |
2735 | ||
72667f08 LP |
2736 | } else if (r == 0) { |
2737 | DnssecNsecResult nr; | |
ed29bfdc | 2738 | bool authenticated = false; |
72667f08 LP |
2739 | |
2740 | /* Bummer! Let's check NSEC/NSEC3 */ | |
0c7bff0a | 2741 | r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); |
72667f08 LP |
2742 | if (r < 0) |
2743 | return r; | |
2744 | ||
2745 | switch (nr) { | |
2746 | ||
2747 | case DNSSEC_NSEC_NXDOMAIN: | |
2748 | /* NSEC proves the domain doesn't exist. Very good. */ | |
105e1512 | 2749 | log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t)); |
019036a4 | 2750 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 2751 | t->answer_rcode = DNS_RCODE_NXDOMAIN; |
ed29bfdc | 2752 | t->answer_authenticated = authenticated; |
72667f08 LP |
2753 | break; |
2754 | ||
2755 | case DNSSEC_NSEC_NODATA: | |
2756 | /* NSEC proves that there's no data here, very good. */ | |
105e1512 | 2757 | log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t)); |
019036a4 | 2758 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 2759 | t->answer_rcode = DNS_RCODE_SUCCESS; |
ed29bfdc | 2760 | t->answer_authenticated = authenticated; |
72667f08 LP |
2761 | break; |
2762 | ||
105e1512 LP |
2763 | case DNSSEC_NSEC_OPTOUT: |
2764 | /* NSEC3 says the data might not be signed */ | |
2765 | log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t)); | |
019036a4 | 2766 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
2767 | t->answer_authenticated = false; |
2768 | break; | |
2769 | ||
72667f08 LP |
2770 | case DNSSEC_NSEC_NO_RR: |
2771 | /* No NSEC data? Bummer! */ | |
105e1512 LP |
2772 | |
2773 | r = dns_transaction_requires_nsec(t); | |
2774 | if (r < 0) | |
2775 | return r; | |
2776 | if (r > 0) | |
019036a4 | 2777 | t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; |
105e1512 | 2778 | else { |
019036a4 | 2779 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
2780 | t->answer_authenticated = false; |
2781 | } | |
2782 | ||
2783 | break; | |
2784 | ||
2785 | case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: | |
2786 | /* We don't know the NSEC3 algorithm used? */ | |
019036a4 | 2787 | t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; |
72667f08 LP |
2788 | break; |
2789 | ||
2790 | case DNSSEC_NSEC_FOUND: | |
146035b3 | 2791 | case DNSSEC_NSEC_CNAME: |
72667f08 | 2792 | /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ |
019036a4 | 2793 | t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; |
72667f08 LP |
2794 | break; |
2795 | ||
2796 | default: | |
2797 | assert_not_reached("Unexpected NSEC result."); | |
2798 | } | |
2799 | } | |
2800 | ||
547973de LP |
2801 | return 1; |
2802 | } | |
2803 | ||
a5784c49 LP |
2804 | const char *dns_transaction_key_string(DnsTransaction *t) { |
2805 | assert(t); | |
2806 | ||
2807 | if (!t->key_string) { | |
2808 | if (dns_resource_key_to_string(t->key, &t->key_string) < 0) | |
2809 | return "n/a"; | |
2810 | } | |
2811 | ||
2812 | return strstrip(t->key_string); | |
2813 | } | |
2814 | ||
ec2c5e43 LP |
2815 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { |
2816 | [DNS_TRANSACTION_NULL] = "null", | |
2817 | [DNS_TRANSACTION_PENDING] = "pending", | |
547973de | 2818 | [DNS_TRANSACTION_VALIDATING] = "validating", |
3bbdc31d | 2819 | [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", |
ec2c5e43 LP |
2820 | [DNS_TRANSACTION_SUCCESS] = "success", |
2821 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
2822 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
2823 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
2824 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
2825 | [DNS_TRANSACTION_RESOURCES] = "resources", | |
2826 | [DNS_TRANSACTION_ABORTED] = "aborted", | |
547973de | 2827 | [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", |
b2b796b8 | 2828 | [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", |
91adc4db | 2829 | [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", |
ec2c5e43 LP |
2830 | }; |
2831 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); | |
c3bc53e6 LP |
2832 | |
2833 | static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { | |
2834 | [DNS_TRANSACTION_NETWORK] = "network", | |
2835 | [DNS_TRANSACTION_CACHE] = "cache", | |
2836 | [DNS_TRANSACTION_ZONE] = "zone", | |
0d2cd476 | 2837 | [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", |
c3bc53e6 LP |
2838 | }; |
2839 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); |