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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
ec2c5e43 LP |
2 | /*** |
3 | This file is part of systemd. | |
4 | ||
5 | Copyright 2014 Lennart Poettering | |
6 | ||
7 | systemd is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU Lesser General Public License as published by | |
9 | the Free Software Foundation; either version 2.1 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | systemd is distributed in the hope that it will be useful, but | |
13 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | Lesser General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public License | |
18 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
19 | ***/ | |
20 | ||
62cc1c55 | 21 | #include "sd-messages.h" |
beef6a5f | 22 | |
ec2c5e43 | 23 | #include "af-list.h" |
b5efdb8a | 24 | #include "alloc-util.h" |
f52e61da | 25 | #include "dns-domain.h" |
7cc6ed7b | 26 | #include "errno-list.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 | |
b214dc0f | 34 | #define TRANSACTIONS_MAX 4096 |
dc349f5f | 35 | #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC) |
b214dc0f | 36 | |
c61d2b44 LP |
37 | static void dns_transaction_reset_answer(DnsTransaction *t) { |
38 | assert(t); | |
39 | ||
40 | t->received = dns_packet_unref(t->received); | |
41 | t->answer = dns_answer_unref(t->answer); | |
42 | t->answer_rcode = 0; | |
43 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; | |
44 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; | |
45 | t->answer_authenticated = false; | |
d3760be0 | 46 | t->answer_nsec_ttl = (uint32_t) -1; |
7cc6ed7b | 47 | t->answer_errno = 0; |
c61d2b44 LP |
48 | } |
49 | ||
c5b4f861 LP |
50 | static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { |
51 | DnsTransaction *z; | |
52 | ||
53 | assert(t); | |
54 | ||
55 | while ((z = set_steal_first(t->dnssec_transactions))) { | |
56 | set_remove(z->notify_transactions, t); | |
35aa04e9 | 57 | set_remove(z->notify_transactions_done, t); |
c5b4f861 LP |
58 | dns_transaction_gc(z); |
59 | } | |
60 | } | |
61 | ||
f32f0e57 LP |
62 | static void dns_transaction_close_connection(DnsTransaction *t) { |
63 | assert(t); | |
64 | ||
b30bf55d LP |
65 | if (t->stream) { |
66 | /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ | |
67 | t->stream->complete = NULL; | |
68 | t->stream->on_packet = NULL; | |
69 | t->stream->transaction = NULL; | |
70 | t->stream = dns_stream_unref(t->stream); | |
71 | } | |
72 | ||
f32f0e57 LP |
73 | t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); |
74 | t->dns_udp_fd = safe_close(t->dns_udp_fd); | |
75 | } | |
76 | ||
f535705a | 77 | static void dns_transaction_stop_timeout(DnsTransaction *t) { |
97cc656c LP |
78 | assert(t); |
79 | ||
80 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
97cc656c LP |
81 | } |
82 | ||
ec2c5e43 | 83 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { |
801ad6a6 | 84 | DnsQueryCandidate *c; |
ec2c5e43 | 85 | DnsZoneItem *i; |
547973de | 86 | DnsTransaction *z; |
ec2c5e43 LP |
87 | |
88 | if (!t) | |
89 | return NULL; | |
90 | ||
51e399bc LP |
91 | log_debug("Freeing transaction %" PRIu16 ".", t->id); |
92 | ||
f32f0e57 | 93 | dns_transaction_close_connection(t); |
f535705a | 94 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 95 | |
ec2c5e43 | 96 | dns_packet_unref(t->sent); |
c61d2b44 | 97 | dns_transaction_reset_answer(t); |
ec2c5e43 | 98 | |
8300ba21 | 99 | dns_server_unref(t->server); |
ec2c5e43 LP |
100 | |
101 | if (t->scope) { | |
f9ebb22a LP |
102 | hashmap_remove_value(t->scope->transactions_by_key, t->key, t); |
103 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
ec2c5e43 LP |
104 | |
105 | if (t->id != 0) | |
106 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
107 | } | |
108 | ||
547973de | 109 | while ((c = set_steal_first(t->notify_query_candidates))) |
801ad6a6 | 110 | set_remove(c->transactions, t); |
547973de | 111 | set_free(t->notify_query_candidates); |
801ad6a6 | 112 | |
35aa04e9 LP |
113 | while ((c = set_steal_first(t->notify_query_candidates_done))) |
114 | set_remove(c->transactions, t); | |
115 | set_free(t->notify_query_candidates_done); | |
116 | ||
547973de | 117 | while ((i = set_steal_first(t->notify_zone_items))) |
ec2c5e43 | 118 | i->probe_transaction = NULL; |
547973de LP |
119 | set_free(t->notify_zone_items); |
120 | ||
35aa04e9 LP |
121 | while ((i = set_steal_first(t->notify_zone_items_done))) |
122 | i->probe_transaction = NULL; | |
123 | set_free(t->notify_zone_items_done); | |
124 | ||
547973de LP |
125 | while ((z = set_steal_first(t->notify_transactions))) |
126 | set_remove(z->dnssec_transactions, t); | |
127 | set_free(t->notify_transactions); | |
128 | ||
35aa04e9 LP |
129 | while ((z = set_steal_first(t->notify_transactions_done))) |
130 | set_remove(z->dnssec_transactions, t); | |
131 | set_free(t->notify_transactions_done); | |
132 | ||
c5b4f861 | 133 | dns_transaction_flush_dnssec_transactions(t); |
547973de LP |
134 | set_free(t->dnssec_transactions); |
135 | ||
136 | dns_answer_unref(t->validated_keys); | |
97cc656c | 137 | dns_resource_key_unref(t->key); |
97cc656c | 138 | |
6b430fdb | 139 | return mfree(t); |
ec2c5e43 LP |
140 | } |
141 | ||
142 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
143 | ||
51e399bc | 144 | bool dns_transaction_gc(DnsTransaction *t) { |
ec2c5e43 LP |
145 | assert(t); |
146 | ||
147 | if (t->block_gc > 0) | |
51e399bc | 148 | return true; |
ec2c5e43 | 149 | |
547973de | 150 | if (set_isempty(t->notify_query_candidates) && |
35aa04e9 | 151 | set_isempty(t->notify_query_candidates_done) && |
547973de | 152 | set_isempty(t->notify_zone_items) && |
35aa04e9 LP |
153 | set_isempty(t->notify_zone_items_done) && |
154 | set_isempty(t->notify_transactions) && | |
155 | set_isempty(t->notify_transactions_done)) { | |
ec2c5e43 | 156 | dns_transaction_free(t); |
51e399bc LP |
157 | return false; |
158 | } | |
159 | ||
160 | return true; | |
ec2c5e43 LP |
161 | } |
162 | ||
4dd15077 LP |
163 | static uint16_t pick_new_id(Manager *m) { |
164 | uint16_t new_id; | |
165 | ||
166 | /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of | |
167 | * transactions, and it's much lower than the space of IDs. */ | |
168 | ||
169 | assert_cc(TRANSACTIONS_MAX < 0xFFFF); | |
170 | ||
171 | do | |
172 | random_bytes(&new_id, sizeof(new_id)); | |
173 | while (new_id == 0 || | |
174 | hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id))); | |
175 | ||
176 | return new_id; | |
177 | } | |
178 | ||
f52e61da | 179 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { |
ec2c5e43 LP |
180 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; |
181 | int r; | |
182 | ||
183 | assert(ret); | |
184 | assert(s); | |
f52e61da | 185 | assert(key); |
ec2c5e43 | 186 | |
9eae2bf3 | 187 | /* Don't allow looking up invalid or pseudo RRs */ |
c463eb78 | 188 | if (!dns_type_is_valid_query(key->type)) |
9eae2bf3 | 189 | return -EINVAL; |
d0129ddb LP |
190 | if (dns_type_is_obsolete(key->type)) |
191 | return -EOPNOTSUPP; | |
9eae2bf3 LP |
192 | |
193 | /* We only support the IN class */ | |
4c701096 | 194 | if (!IN_SET(key->class, DNS_CLASS_IN, DNS_CLASS_ANY)) |
9eae2bf3 LP |
195 | return -EOPNOTSUPP; |
196 | ||
b214dc0f LP |
197 | if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX) |
198 | return -EBUSY; | |
199 | ||
d5099efc | 200 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
201 | if (r < 0) |
202 | return r; | |
203 | ||
f9ebb22a | 204 | r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); |
da0c630e LP |
205 | if (r < 0) |
206 | return r; | |
207 | ||
ec2c5e43 LP |
208 | t = new0(DnsTransaction, 1); |
209 | if (!t) | |
210 | return -ENOMEM; | |
211 | ||
4667e00a | 212 | t->dns_udp_fd = -1; |
c3bc53e6 | 213 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; |
019036a4 | 214 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
d3760be0 | 215 | t->answer_nsec_ttl = (uint32_t) -1; |
f52e61da | 216 | t->key = dns_resource_key_ref(key); |
274b8748 | 217 | t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
d001e0a3 | 218 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
ec2c5e43 | 219 | |
4dd15077 | 220 | t->id = pick_new_id(s->manager); |
ec2c5e43 LP |
221 | |
222 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
223 | if (r < 0) { | |
224 | t->id = 0; | |
225 | return r; | |
226 | } | |
227 | ||
f9ebb22a | 228 | r = hashmap_replace(s->transactions_by_key, t->key, t); |
da0c630e LP |
229 | if (r < 0) { |
230 | hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
231 | return r; | |
232 | } | |
233 | ||
f9ebb22a | 234 | LIST_PREPEND(transactions_by_scope, s->transactions, t); |
ec2c5e43 LP |
235 | t->scope = s; |
236 | ||
313cefa1 | 237 | s->manager->n_transactions_total++; |
a150ff5e | 238 | |
ec2c5e43 LP |
239 | if (ret) |
240 | *ret = t; | |
241 | ||
242 | t = NULL; | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
4dd15077 LP |
247 | static void dns_transaction_shuffle_id(DnsTransaction *t) { |
248 | uint16_t new_id; | |
249 | assert(t); | |
250 | ||
251 | /* Pick a new ID for this transaction. */ | |
252 | ||
253 | new_id = pick_new_id(t->scope->manager); | |
254 | assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0); | |
255 | ||
256 | log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id); | |
257 | t->id = new_id; | |
258 | ||
259 | /* Make sure we generate a new packet with the new ID */ | |
260 | t->sent = dns_packet_unref(t->sent); | |
261 | } | |
262 | ||
ec2c5e43 | 263 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { |
2fb3034c | 264 | _cleanup_free_ char *pretty = NULL; |
202b76ae | 265 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 | 266 | DnsZoneItem *z; |
ec2c5e43 LP |
267 | |
268 | assert(t); | |
269 | assert(p); | |
270 | ||
271 | if (manager_our_packet(t->scope->manager, p) != 0) | |
272 | return; | |
273 | ||
164d025d | 274 | (void) in_addr_to_string(p->family, &p->sender, &pretty); |
2fb3034c | 275 | |
a5784c49 LP |
276 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", |
277 | t->id, | |
202b76ae | 278 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
279 | dns_protocol_to_string(t->scope->protocol), |
280 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 281 | af_to_name_short(t->scope->family), |
164d025d | 282 | strnull(pretty)); |
ec2c5e43 | 283 | |
a4076574 LP |
284 | /* RFC 4795, Section 4.1 says that the peer with the |
285 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
286 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
287 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
288 | return; |
289 | } | |
290 | ||
4d91eec4 | 291 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 292 | |
ec2c5e43 | 293 | t->block_gc++; |
35aa04e9 | 294 | |
547973de | 295 | while ((z = set_first(t->notify_zone_items))) { |
3ef64445 LP |
296 | /* First, make sure the zone item drops the reference |
297 | * to us */ | |
298 | dns_zone_item_probe_stop(z); | |
299 | ||
300 | /* Secondly, report this as conflict, so that we might | |
301 | * look for a different hostname */ | |
ec2c5e43 | 302 | dns_zone_item_conflict(z); |
3ef64445 | 303 | } |
ec2c5e43 LP |
304 | t->block_gc--; |
305 | ||
306 | dns_transaction_gc(t); | |
307 | } | |
308 | ||
309 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
801ad6a6 | 310 | DnsQueryCandidate *c; |
ec2c5e43 | 311 | DnsZoneItem *z; |
547973de | 312 | DnsTransaction *d; |
7cc6ed7b | 313 | const char *st; |
202b76ae | 314 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 LP |
315 | |
316 | assert(t); | |
547973de | 317 | assert(!DNS_TRANSACTION_IS_LIVE(state)); |
e56187ca | 318 | |
202b76ae ZJS |
319 | if (state == DNS_TRANSACTION_DNSSEC_FAILED) { |
320 | dns_resource_key_to_string(t->key, key_str, sizeof key_str); | |
321 | ||
f61dfddb | 322 | log_struct(LOG_NOTICE, |
2b044526 | 323 | "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR, |
202b76ae | 324 | LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str, dnssec_result_to_string(t->answer_dnssec_result)), |
f61dfddb | 325 | "DNS_TRANSACTION=%" PRIu16, t->id, |
202b76ae | 326 | "DNS_QUESTION=%s", key_str, |
f61dfddb | 327 | "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), |
1e02e182 LP |
328 | "DNS_SERVER=%s", dns_server_string(t->server), |
329 | "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t->server->possible_feature_level), | |
f61dfddb | 330 | NULL); |
202b76ae | 331 | } |
f61dfddb | 332 | |
ec2c5e43 LP |
333 | /* Note that this call might invalidate the query. Callers |
334 | * should hence not attempt to access the query or transaction | |
335 | * after calling this function. */ | |
336 | ||
7cc6ed7b LP |
337 | if (state == DNS_TRANSACTION_ERRNO) |
338 | st = errno_to_name(t->answer_errno); | |
339 | else | |
340 | st = dns_transaction_state_to_string(state); | |
341 | ||
a5784c49 LP |
342 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", |
343 | t->id, | |
202b76ae | 344 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
345 | dns_protocol_to_string(t->scope->protocol), |
346 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 347 | af_to_name_short(t->scope->family), |
7cc6ed7b | 348 | st, |
a5784c49 LP |
349 | t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), |
350 | t->answer_authenticated ? "authenticated" : "unsigned"); | |
ec2c5e43 LP |
351 | |
352 | t->state = state; | |
353 | ||
f32f0e57 | 354 | dns_transaction_close_connection(t); |
f535705a | 355 | dns_transaction_stop_timeout(t); |
ec2c5e43 LP |
356 | |
357 | /* Notify all queries that are interested, but make sure the | |
358 | * transaction isn't freed while we are still looking at it */ | |
359 | t->block_gc++; | |
f7014757 | 360 | |
35aa04e9 | 361 | SET_FOREACH_MOVE(c, t->notify_query_candidates_done, t->notify_query_candidates) |
547973de | 362 | dns_query_candidate_notify(c); |
35aa04e9 | 363 | SWAP_TWO(t->notify_query_candidates, t->notify_query_candidates_done); |
ec2c5e43 | 364 | |
35aa04e9 LP |
365 | SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items) |
366 | dns_zone_item_notify(z); | |
367 | SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done); | |
c3ae4188 | 368 | if (t->probing) |
1a63fc54 | 369 | (void) dns_scope_announce(t->scope, false); |
f7014757 | 370 | |
35aa04e9 LP |
371 | SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions) |
372 | dns_transaction_notify(d, t); | |
373 | SWAP_TWO(t->notify_transactions, t->notify_transactions_done); | |
f7014757 LP |
374 | |
375 | t->block_gc--; | |
ec2c5e43 LP |
376 | dns_transaction_gc(t); |
377 | } | |
378 | ||
519ef046 LP |
379 | static int dns_transaction_pick_server(DnsTransaction *t) { |
380 | DnsServer *server; | |
381 | ||
382 | assert(t); | |
383 | assert(t->scope->protocol == DNS_PROTOCOL_DNS); | |
384 | ||
d001e0a3 LP |
385 | /* Pick a DNS server and a feature level for it. */ |
386 | ||
519ef046 LP |
387 | server = dns_scope_get_dns_server(t->scope); |
388 | if (!server) | |
389 | return -ESRCH; | |
390 | ||
d001e0a3 LP |
391 | /* If we changed the server invalidate the feature level clamping, as the new server might have completely |
392 | * different properties. */ | |
393 | if (server != t->server) | |
394 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; | |
395 | ||
274b8748 | 396 | t->current_feature_level = dns_server_possible_feature_level(server); |
519ef046 | 397 | |
d001e0a3 LP |
398 | /* Clamp the feature level if that is requested. */ |
399 | if (t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID && | |
400 | t->current_feature_level > t->clamp_feature_level) | |
401 | t->current_feature_level = t->clamp_feature_level; | |
402 | ||
403 | log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t->current_feature_level), t->id); | |
404 | ||
519ef046 LP |
405 | if (server == t->server) |
406 | return 0; | |
407 | ||
408 | dns_server_unref(t->server); | |
409 | t->server = dns_server_ref(server); | |
410 | ||
d001e0a3 LP |
411 | log_debug("Using DNS server %s for transaction %u.", dns_server_string(t->server), t->id); |
412 | ||
519ef046 LP |
413 | return 1; |
414 | } | |
415 | ||
d001e0a3 | 416 | static void dns_transaction_retry(DnsTransaction *t, bool next_server) { |
8d10d620 LP |
417 | int r; |
418 | ||
419 | assert(t); | |
420 | ||
421 | log_debug("Retrying transaction %" PRIu16 ".", t->id); | |
422 | ||
423 | /* Before we try again, switch to a new server. */ | |
d001e0a3 LP |
424 | if (next_server) |
425 | dns_scope_next_dns_server(t->scope); | |
8d10d620 LP |
426 | |
427 | r = dns_transaction_go(t); | |
7cc6ed7b LP |
428 | if (r < 0) { |
429 | t->answer_errno = -r; | |
430 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
431 | } | |
8d10d620 LP |
432 | } |
433 | ||
c02cf2f4 | 434 | static int dns_transaction_maybe_restart(DnsTransaction *t) { |
5278bbfe LP |
435 | int r; |
436 | ||
c02cf2f4 LP |
437 | assert(t); |
438 | ||
5278bbfe LP |
439 | /* Returns > 0 if the transaction was restarted, 0 if not */ |
440 | ||
c02cf2f4 LP |
441 | if (!t->server) |
442 | return 0; | |
443 | ||
444 | if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) | |
445 | return 0; | |
446 | ||
447 | /* The server's current feature level is lower than when we sent the original query. We learnt something from | |
448 | the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to | |
449 | restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include | |
450 | OPT RR or DO bit. One of these cases is documented here, for example: | |
451 | https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ | |
452 | ||
4dd15077 LP |
453 | log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID."); |
454 | dns_transaction_shuffle_id(t); | |
5278bbfe LP |
455 | |
456 | r = dns_transaction_go(t); | |
457 | if (r < 0) | |
458 | return r; | |
459 | ||
460 | return 1; | |
c02cf2f4 LP |
461 | } |
462 | ||
ec2c5e43 LP |
463 | static int on_stream_complete(DnsStream *s, int error) { |
464 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
465 | DnsTransaction *t; | |
466 | ||
467 | assert(s); | |
468 | assert(s->transaction); | |
469 | ||
470 | /* Copy the data we care about out of the stream before we | |
471 | * destroy it. */ | |
472 | t = s->transaction; | |
473 | p = dns_packet_ref(s->read_packet); | |
474 | ||
b30bf55d | 475 | dns_transaction_close_connection(t); |
ec2c5e43 | 476 | |
a1a3f73a LP |
477 | if (ERRNO_IS_DISCONNECT(error)) { |
478 | usec_t usec; | |
479 | ||
0791110f LP |
480 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { |
481 | /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the | |
482 | * question on this scope. */ | |
483 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
484 | return 0; | |
485 | } | |
486 | ||
92ec902a | 487 | log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); |
a1a3f73a | 488 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
274b8748 | 489 | dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level, usec - t->start_usec); |
a1a3f73a | 490 | |
d001e0a3 | 491 | dns_transaction_retry(t, true); |
ac720200 LP |
492 | return 0; |
493 | } | |
ec2c5e43 | 494 | if (error != 0) { |
7cc6ed7b LP |
495 | t->answer_errno = error; |
496 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 LP |
497 | return 0; |
498 | } | |
499 | ||
a4076574 | 500 | if (dns_packet_validate_reply(p) <= 0) { |
a20b9592 | 501 | log_debug("Invalid TCP reply packet."); |
a4076574 LP |
502 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
503 | return 0; | |
504 | } | |
505 | ||
506 | dns_scope_check_conflicts(t->scope, p); | |
507 | ||
ec2c5e43 LP |
508 | t->block_gc++; |
509 | dns_transaction_process_reply(t, p); | |
510 | t->block_gc--; | |
511 | ||
519ef046 LP |
512 | /* If the response wasn't useful, then complete the transition |
513 | * now. After all, we are the worst feature set now with TCP | |
514 | * sockets, and there's really no point in retrying. */ | |
ec2c5e43 LP |
515 | if (t->state == DNS_TRANSACTION_PENDING) |
516 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
598f44bd LP |
517 | else |
518 | dns_transaction_gc(t); | |
ec2c5e43 LP |
519 | |
520 | return 0; | |
521 | } | |
522 | ||
523 | static int dns_transaction_open_tcp(DnsTransaction *t) { | |
524 | _cleanup_close_ int fd = -1; | |
525 | int r; | |
526 | ||
527 | assert(t); | |
528 | ||
519ef046 | 529 | dns_transaction_close_connection(t); |
ec2c5e43 | 530 | |
106784eb | 531 | switch (t->scope->protocol) { |
519ef046 | 532 | |
106784eb | 533 | case DNS_PROTOCOL_DNS: |
519ef046 LP |
534 | r = dns_transaction_pick_server(t); |
535 | if (r < 0) | |
536 | return r; | |
537 | ||
92ec902a | 538 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
539 | return -EOPNOTSUPP; |
540 | ||
274b8748 | 541 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
542 | if (r < 0) |
543 | return r; | |
544 | ||
545 | fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, 53); | |
106784eb | 546 | break; |
ec2c5e43 | 547 | |
106784eb | 548 | case DNS_PROTOCOL_LLMNR: |
a8f6397f | 549 | /* When we already received a reply to this (but it was truncated), send to its sender address */ |
ec2c5e43 | 550 | if (t->received) |
519ef046 | 551 | fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port); |
ec2c5e43 LP |
552 | else { |
553 | union in_addr_union address; | |
a7f7d1bd | 554 | int family = AF_UNSPEC; |
ec2c5e43 LP |
555 | |
556 | /* Otherwise, try to talk to the owner of a | |
557 | * the IP address, in case this is a reverse | |
558 | * PTR lookup */ | |
f52e61da | 559 | |
1c02e7ba | 560 | r = dns_name_address(dns_resource_key_name(t->key), &family, &address); |
ec2c5e43 LP |
561 | if (r < 0) |
562 | return r; | |
563 | if (r == 0) | |
564 | return -EINVAL; | |
9e08a6e0 | 565 | if (family != t->scope->family) |
9318cdd3 | 566 | return -ESRCH; |
ec2c5e43 | 567 | |
519ef046 | 568 | fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT); |
ec2c5e43 | 569 | } |
106784eb DM |
570 | |
571 | break; | |
572 | ||
573 | default: | |
ec2c5e43 | 574 | return -EAFNOSUPPORT; |
106784eb | 575 | } |
ec2c5e43 LP |
576 | |
577 | if (fd < 0) | |
578 | return fd; | |
579 | ||
580 | r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd); | |
581 | if (r < 0) | |
582 | return r; | |
ec2c5e43 LP |
583 | fd = -1; |
584 | ||
585 | r = dns_stream_write_packet(t->stream, t->sent); | |
586 | if (r < 0) { | |
b30bf55d | 587 | t->stream = dns_stream_unref(t->stream); |
ec2c5e43 LP |
588 | return r; |
589 | } | |
590 | ||
ec2c5e43 LP |
591 | t->stream->complete = on_stream_complete; |
592 | t->stream->transaction = t; | |
593 | ||
594 | /* The interface index is difficult to determine if we are | |
595 | * connecting to the local host, hence fill this in right away | |
596 | * instead of determining it from the socket */ | |
97ebebbc | 597 | t->stream->ifindex = dns_scope_ifindex(t->scope); |
ec2c5e43 | 598 | |
519ef046 LP |
599 | dns_transaction_reset_answer(t); |
600 | ||
cbe4216d LP |
601 | t->tried_stream = true; |
602 | ||
ec2c5e43 LP |
603 | return 0; |
604 | } | |
605 | ||
547973de | 606 | static void dns_transaction_cache_answer(DnsTransaction *t) { |
547973de LP |
607 | assert(t); |
608 | ||
609 | /* For mDNS we cache whenever we get the packet, rather than | |
610 | * in each transaction. */ | |
611 | if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) | |
612 | return; | |
613 | ||
ceeddf79 MP |
614 | /* Caching disabled? */ |
615 | if (!t->scope->manager->enable_cache) | |
616 | return; | |
617 | ||
547973de LP |
618 | /* We never cache if this packet is from the local host, under |
619 | * the assumption that a locally running DNS server would | |
620 | * cache this anyway, and probably knows better when to flush | |
621 | * the cache then we could. */ | |
622 | if (!DNS_PACKET_SHALL_CACHE(t->received)) | |
623 | return; | |
624 | ||
547973de LP |
625 | dns_cache_put(&t->scope->cache, |
626 | t->key, | |
627 | t->answer_rcode, | |
628 | t->answer, | |
547973de | 629 | t->answer_authenticated, |
d3760be0 | 630 | t->answer_nsec_ttl, |
547973de LP |
631 | 0, |
632 | t->received->family, | |
633 | &t->received->sender); | |
634 | } | |
635 | ||
105e1512 LP |
636 | static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { |
637 | DnsTransaction *dt; | |
638 | Iterator i; | |
639 | ||
640 | assert(t); | |
641 | ||
642 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
643 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
644 | return true; | |
645 | ||
646 | return false; | |
647 | } | |
648 | ||
942eb2e7 LP |
649 | static int dns_transaction_dnssec_ready(DnsTransaction *t) { |
650 | DnsTransaction *dt; | |
651 | Iterator i; | |
652 | ||
653 | assert(t); | |
654 | ||
655 | /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still | |
656 | * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */ | |
657 | ||
658 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
659 | ||
660 | switch (dt->state) { | |
661 | ||
662 | case DNS_TRANSACTION_NULL: | |
663 | case DNS_TRANSACTION_PENDING: | |
664 | case DNS_TRANSACTION_VALIDATING: | |
665 | /* Still ongoing */ | |
666 | return 0; | |
667 | ||
668 | case DNS_TRANSACTION_RCODE_FAILURE: | |
b3c6b00a | 669 | if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) { |
942eb2e7 LP |
670 | log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode)); |
671 | goto fail; | |
672 | } | |
673 | ||
b3c6b00a LP |
674 | /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers |
675 | * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS | |
676 | * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar | |
677 | * RRs to make unsigned proofs. */ | |
942eb2e7 LP |
678 | |
679 | case DNS_TRANSACTION_SUCCESS: | |
680 | /* All good. */ | |
681 | break; | |
682 | ||
683 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
684 | /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC | |
685 | * validationr result */ | |
686 | ||
687 | log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result)); | |
688 | t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */ | |
689 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
690 | return 0; | |
691 | ||
692 | ||
693 | default: | |
694 | log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state)); | |
695 | goto fail; | |
696 | } | |
697 | } | |
698 | ||
699 | /* All is ready, we can go and validate */ | |
700 | return 1; | |
701 | ||
702 | fail: | |
703 | t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; | |
704 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
705 | return 0; | |
706 | } | |
707 | ||
547973de LP |
708 | static void dns_transaction_process_dnssec(DnsTransaction *t) { |
709 | int r; | |
710 | ||
711 | assert(t); | |
712 | ||
713 | /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ | |
942eb2e7 | 714 | r = dns_transaction_dnssec_ready(t); |
7cc6ed7b LP |
715 | if (r < 0) |
716 | goto fail; | |
942eb2e7 | 717 | if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */ |
547973de LP |
718 | return; |
719 | ||
c02cf2f4 LP |
720 | /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better |
721 | * restart the lookup immediately. */ | |
722 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
723 | if (r < 0) |
724 | goto fail; | |
c02cf2f4 LP |
725 | if (r > 0) /* Transaction got restarted... */ |
726 | return; | |
727 | ||
547973de LP |
728 | /* All our auxiliary DNSSEC transactions are complete now. Try |
729 | * to validate our RRset now. */ | |
730 | r = dns_transaction_validate_dnssec(t); | |
fcfaff12 LP |
731 | if (r == -EBADMSG) { |
732 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
733 | return; | |
734 | } | |
7cc6ed7b LP |
735 | if (r < 0) |
736 | goto fail; | |
547973de | 737 | |
b652d4a2 LP |
738 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && |
739 | t->scope->dnssec_mode == DNSSEC_YES) { | |
740 | /* We are not in automatic downgrade mode, and the | |
741 | * server is bad, refuse operation. */ | |
742 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
743 | return; | |
744 | } | |
745 | ||
019036a4 | 746 | if (!IN_SET(t->answer_dnssec_result, |
b652d4a2 LP |
747 | _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ |
748 | DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ | |
749 | DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ | |
750 | DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ | |
547973de LP |
751 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
752 | return; | |
753 | } | |
754 | ||
1e02e182 LP |
755 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER) |
756 | dns_server_warn_downgrade(t->server); | |
757 | ||
547973de LP |
758 | dns_transaction_cache_answer(t); |
759 | ||
760 | if (t->answer_rcode == DNS_RCODE_SUCCESS) | |
761 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
762 | else | |
3bbdc31d | 763 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
7cc6ed7b LP |
764 | |
765 | return; | |
766 | ||
767 | fail: | |
768 | t->answer_errno = -r; | |
769 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
547973de LP |
770 | } |
771 | ||
eac7cda2 LP |
772 | static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { |
773 | int r; | |
774 | ||
775 | assert(t); | |
776 | ||
777 | /* Checks whether the answer is positive, i.e. either a direct | |
778 | * answer to the question, or a CNAME/DNAME for it */ | |
779 | ||
780 | r = dns_answer_match_key(t->answer, t->key, flags); | |
781 | if (r != 0) | |
782 | return r; | |
783 | ||
784 | r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); | |
785 | if (r != 0) | |
786 | return r; | |
787 | ||
788 | return false; | |
789 | } | |
790 | ||
791 | static int dns_transaction_fix_rcode(DnsTransaction *t) { | |
792 | int r; | |
793 | ||
794 | assert(t); | |
795 | ||
796 | /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the | |
797 | * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a | |
798 | * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first | |
799 | * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when | |
800 | * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle | |
801 | * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a | |
802 | * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server | |
803 | * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an | |
804 | * incomplete CNAME/DNAME chain. | |
805 | * | |
806 | * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS, | |
807 | * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new | |
808 | * lookup. */ | |
809 | ||
810 | if (t->answer_rcode != DNS_RCODE_NXDOMAIN) | |
811 | return 0; | |
812 | ||
813 | r = dns_transaction_has_positive_answer(t, NULL); | |
814 | if (r <= 0) | |
815 | return r; | |
816 | ||
817 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
818 | return 0; | |
819 | } | |
820 | ||
ec2c5e43 | 821 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { |
9df3ba6c | 822 | usec_t ts; |
ec2c5e43 LP |
823 | int r; |
824 | ||
825 | assert(t); | |
826 | assert(p); | |
9df3ba6c TG |
827 | assert(t->scope); |
828 | assert(t->scope->manager); | |
ec2c5e43 | 829 | |
5a7e41a3 LP |
830 | if (t->state != DNS_TRANSACTION_PENDING) |
831 | return; | |
832 | ||
ec2c5e43 LP |
833 | /* Note that this call might invalidate the query. Callers |
834 | * should hence not attempt to access the query or transaction | |
835 | * after calling this function. */ | |
836 | ||
1fdeaeb7 | 837 | log_debug("Processing incoming packet on transaction %" PRIu16". (rcode=%s)", t->id, dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
b5efcf29 | 838 | |
106784eb | 839 | switch (t->scope->protocol) { |
b5efcf29 | 840 | |
106784eb | 841 | case DNS_PROTOCOL_LLMNR: |
97ebebbc | 842 | /* For LLMNR we will not accept any packets from other interfaces */ |
ec2c5e43 | 843 | |
97ebebbc | 844 | if (p->ifindex != dns_scope_ifindex(t->scope)) |
ec2c5e43 LP |
845 | return; |
846 | ||
847 | if (p->family != t->scope->family) | |
848 | return; | |
849 | ||
850 | /* Tentative packets are not full responses but still | |
851 | * useful for identifying uniqueness conflicts during | |
852 | * probing. */ | |
8b757a38 | 853 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
854 | dns_transaction_tentative(t, p); |
855 | return; | |
856 | } | |
106784eb DM |
857 | |
858 | break; | |
859 | ||
4e5bf5e1 | 860 | case DNS_PROTOCOL_MDNS: |
4e5bf5e1 | 861 | /* For mDNS we will not accept any packets from other interfaces */ |
97ebebbc LP |
862 | |
863 | if (p->ifindex != dns_scope_ifindex(t->scope)) | |
4e5bf5e1 DM |
864 | return; |
865 | ||
866 | if (p->family != t->scope->family) | |
867 | return; | |
868 | ||
869 | break; | |
870 | ||
106784eb | 871 | case DNS_PROTOCOL_DNS: |
8ad182a1 LP |
872 | /* Note that we do not need to verify the |
873 | * addresses/port numbers of incoming traffic, as we | |
874 | * invoked connect() on our UDP socket in which case | |
875 | * the kernel already does the needed verification for | |
876 | * us. */ | |
106784eb DM |
877 | break; |
878 | ||
879 | default: | |
9c56a6f3 | 880 | assert_not_reached("Invalid DNS protocol."); |
ec2c5e43 LP |
881 | } |
882 | ||
ec2c5e43 LP |
883 | if (t->received != p) { |
884 | dns_packet_unref(t->received); | |
885 | t->received = dns_packet_ref(p); | |
886 | } | |
887 | ||
c3bc53e6 LP |
888 | t->answer_source = DNS_TRANSACTION_NETWORK; |
889 | ||
ec2c5e43 LP |
890 | if (p->ipproto == IPPROTO_TCP) { |
891 | if (DNS_PACKET_TC(p)) { | |
892 | /* Truncated via TCP? Somebody must be fucking with us */ | |
893 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
894 | return; | |
895 | } | |
896 | ||
897 | if (DNS_PACKET_ID(p) != t->id) { | |
898 | /* Not the reply to our query? Somebody must be fucking with us */ | |
899 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
900 | return; | |
901 | } | |
902 | } | |
903 | ||
38a03f06 | 904 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
9df3ba6c TG |
905 | |
906 | switch (t->scope->protocol) { | |
8af5b883 | 907 | |
9df3ba6c TG |
908 | case DNS_PROTOCOL_DNS: |
909 | assert(t->server); | |
910 | ||
4e0b8b17 TG |
911 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { |
912 | ||
8af5b883 | 913 | /* Request failed, immediately try again with reduced features */ |
4e0b8b17 | 914 | |
7d581a65 LP |
915 | if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) { |
916 | /* This was already at UDP feature level? If so, it doesn't make sense to downgrade | |
917 | * this transaction anymore, hence let's process the response, and accept the | |
918 | * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate | |
919 | * packet loss, but is not going to give us better rcodes should we actually have | |
920 | * managed to get them already at UDP level. */ | |
921 | ||
d001e0a3 LP |
922 | log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
923 | break; | |
924 | } | |
925 | ||
926 | /* Reduce this feature level by one and try again. */ | |
927 | t->clamp_feature_level = t->current_feature_level - 1; | |
928 | ||
929 | log_debug("Server returned error %s, retrying transaction with reduced feature level %s.", | |
930 | dns_rcode_to_string(DNS_PACKET_RCODE(p)), | |
931 | dns_server_feature_level_to_string(t->clamp_feature_level)); | |
932 | ||
933 | dns_transaction_retry(t, false /* use the same server */); | |
4e0b8b17 | 934 | return; |
eb08640a LP |
935 | } |
936 | ||
937 | if (DNS_PACKET_RCODE(p) == DNS_RCODE_REFUSED) { | |
938 | /* This server refused our request? If so, try again, use a different server */ | |
939 | log_debug("Server returned REFUSED, switching servers, and retrying."); | |
940 | dns_transaction_retry(t, true /* pick a new server */); | |
941 | return; | |
942 | } | |
943 | ||
944 | if (DNS_PACKET_TC(p)) | |
274b8748 | 945 | dns_server_packet_truncated(t->server, t->current_feature_level); |
9df3ba6c TG |
946 | |
947 | break; | |
8af5b883 | 948 | |
9df3ba6c TG |
949 | case DNS_PROTOCOL_LLMNR: |
950 | case DNS_PROTOCOL_MDNS: | |
951 | dns_scope_packet_received(t->scope, ts - t->start_usec); | |
9df3ba6c | 952 | break; |
8af5b883 | 953 | |
9df3ba6c | 954 | default: |
8af5b883 | 955 | assert_not_reached("Invalid DNS protocol."); |
9df3ba6c TG |
956 | } |
957 | ||
ec2c5e43 | 958 | if (DNS_PACKET_TC(p)) { |
547493c5 DM |
959 | |
960 | /* Truncated packets for mDNS are not allowed. Give up immediately. */ | |
961 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) { | |
962 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
963 | return; | |
964 | } | |
965 | ||
f757cd85 LP |
966 | log_debug("Reply truncated, retrying via TCP."); |
967 | ||
ec2c5e43 LP |
968 | /* Response was truncated, let's try again with good old TCP */ |
969 | r = dns_transaction_open_tcp(t); | |
970 | if (r == -ESRCH) { | |
971 | /* No servers found? Damn! */ | |
972 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
973 | return; | |
974 | } | |
91adc4db LP |
975 | if (r == -EOPNOTSUPP) { |
976 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
977 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
978 | return; | |
979 | } | |
ec2c5e43 | 980 | if (r < 0) { |
8af5b883 | 981 | /* On LLMNR, if we cannot connect to the host, |
ec2c5e43 | 982 | * we immediately give up */ |
7cc6ed7b LP |
983 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
984 | goto fail; | |
ec2c5e43 LP |
985 | |
986 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
d001e0a3 | 987 | dns_transaction_retry(t, true); |
ec2c5e43 | 988 | } |
2a6658ef LP |
989 | |
990 | return; | |
ec2c5e43 LP |
991 | } |
992 | ||
de54e62b | 993 | /* After the superficial checks, actually parse the message. */ |
ec2c5e43 LP |
994 | r = dns_packet_extract(p); |
995 | if (r < 0) { | |
996 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
997 | return; | |
998 | } | |
999 | ||
ed9717fc | 1000 | if (t->server) { |
d001e0a3 LP |
1001 | /* Report that we successfully received a valid packet with a good rcode after we initially got a bad |
1002 | * rcode and subsequently downgraded the protocol */ | |
1003 | ||
1004 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN) && | |
1005 | t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID) | |
1006 | dns_server_packet_rcode_downgrade(t->server, t->clamp_feature_level); | |
1007 | ||
1008 | /* Report that the OPT RR was missing */ | |
ed9717fc LP |
1009 | if (!p->opt) |
1010 | dns_server_packet_bad_opt(t->server, t->current_feature_level); | |
1011 | ||
d001e0a3 | 1012 | /* Report that we successfully received a packet */ |
ed9717fc LP |
1013 | dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, ts - t->start_usec, p->size); |
1014 | } | |
de54e62b | 1015 | |
c02cf2f4 LP |
1016 | /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ |
1017 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
1018 | if (r < 0) |
1019 | goto fail; | |
c02cf2f4 LP |
1020 | if (r > 0) /* Transaction got restarted... */ |
1021 | return; | |
1022 | ||
8b419837 | 1023 | if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
b5efcf29 | 1024 | |
8b419837 DR |
1025 | /* When dealing with protocols other than mDNS only consider responses with |
1026 | * equivalent query section to the request. For mDNS this check doesn't make | |
1027 | * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT | |
1028 | * contain any questions in the Question Section". */ | |
1029 | if (t->scope->protocol != DNS_PROTOCOL_MDNS) { | |
1030 | r = dns_packet_is_reply_for(p, t->key); | |
1031 | if (r < 0) | |
1032 | goto fail; | |
1033 | if (r == 0) { | |
1034 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1035 | return; | |
1036 | } | |
547493c5 | 1037 | } |
29815b6c | 1038 | |
547493c5 DM |
1039 | /* Install the answer as answer to the transaction */ |
1040 | dns_answer_unref(t->answer); | |
1041 | t->answer = dns_answer_ref(p->answer); | |
1042 | t->answer_rcode = DNS_PACKET_RCODE(p); | |
919c2ae0 | 1043 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
105e1512 | 1044 | t->answer_authenticated = false; |
79e24931 | 1045 | |
eac7cda2 LP |
1046 | r = dns_transaction_fix_rcode(t); |
1047 | if (r < 0) | |
1048 | goto fail; | |
1049 | ||
51e399bc LP |
1050 | /* Block GC while starting requests for additional DNSSEC RRs */ |
1051 | t->block_gc++; | |
547973de | 1052 | r = dns_transaction_request_dnssec_keys(t); |
51e399bc LP |
1053 | t->block_gc--; |
1054 | ||
1055 | /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ | |
1056 | if (!dns_transaction_gc(t)) | |
1057 | return; | |
1058 | ||
1059 | /* Requesting additional keys might have resulted in | |
1060 | * this transaction to fail, since the auxiliary | |
1061 | * request failed for some reason. If so, we are not | |
1062 | * in pending state anymore, and we should exit | |
1063 | * quickly. */ | |
1064 | if (t->state != DNS_TRANSACTION_PENDING) | |
1065 | return; | |
7cc6ed7b LP |
1066 | if (r < 0) |
1067 | goto fail; | |
547973de LP |
1068 | if (r > 0) { |
1069 | /* There are DNSSEC transactions pending now. Update the state accordingly. */ | |
1070 | t->state = DNS_TRANSACTION_VALIDATING; | |
f535705a LP |
1071 | dns_transaction_close_connection(t); |
1072 | dns_transaction_stop_timeout(t); | |
547973de LP |
1073 | return; |
1074 | } | |
547493c5 | 1075 | } |
ec2c5e43 | 1076 | |
547973de | 1077 | dns_transaction_process_dnssec(t); |
7cc6ed7b LP |
1078 | return; |
1079 | ||
1080 | fail: | |
1081 | t->answer_errno = -r; | |
1082 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 LP |
1083 | } |
1084 | ||
c19ffd9f TG |
1085 | static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
1086 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1087 | DnsTransaction *t = userdata; | |
1088 | int r; | |
1089 | ||
1090 | assert(t); | |
1091 | assert(t->scope); | |
1092 | ||
1093 | r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); | |
7e1851e3 LP |
1094 | if (ERRNO_IS_DISCONNECT(-r)) { |
1095 | usec_t usec; | |
c19ffd9f | 1096 | |
7e1851e3 LP |
1097 | /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next |
1098 | * recvmsg(). Treat this like a lost packet. */ | |
1099 | ||
92ec902a | 1100 | log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); |
7e1851e3 | 1101 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
274b8748 | 1102 | dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level, usec - t->start_usec); |
7e1851e3 | 1103 | |
d001e0a3 | 1104 | dns_transaction_retry(t, true); |
7e1851e3 LP |
1105 | return 0; |
1106 | } | |
1107 | if (r < 0) { | |
7cc6ed7b LP |
1108 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); |
1109 | t->answer_errno = -r; | |
7e1851e3 LP |
1110 | return 0; |
1111 | } | |
1112 | ||
1113 | r = dns_packet_validate_reply(p); | |
1114 | if (r < 0) { | |
1115 | log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); | |
1116 | return 0; | |
1117 | } | |
1118 | if (r == 0) { | |
e09f605e | 1119 | log_debug("Received inappropriate DNS packet as response, ignoring."); |
7e1851e3 LP |
1120 | return 0; |
1121 | } | |
1122 | ||
1123 | if (DNS_PACKET_ID(p) != t->id) { | |
e09f605e | 1124 | log_debug("Received packet with incorrect transaction ID, ignoring."); |
7e1851e3 LP |
1125 | return 0; |
1126 | } | |
c19ffd9f | 1127 | |
7e1851e3 | 1128 | dns_transaction_process_reply(t, p); |
c19ffd9f TG |
1129 | return 0; |
1130 | } | |
1131 | ||
49cce12d | 1132 | static int dns_transaction_emit_udp(DnsTransaction *t) { |
c19ffd9f TG |
1133 | int r; |
1134 | ||
1135 | assert(t); | |
c19ffd9f | 1136 | |
519ef046 | 1137 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { |
c19ffd9f | 1138 | |
519ef046 | 1139 | r = dns_transaction_pick_server(t); |
471d40d9 TG |
1140 | if (r < 0) |
1141 | return r; | |
c19ffd9f | 1142 | |
274b8748 | 1143 | if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP) |
7d581a65 | 1144 | return -EAGAIN; /* Sorry, can't do UDP, try TCP! */ |
519ef046 | 1145 | |
92ec902a | 1146 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
1147 | return -EOPNOTSUPP; |
1148 | ||
519ef046 LP |
1149 | if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ |
1150 | int fd; | |
1151 | ||
1152 | dns_transaction_close_connection(t); | |
c19ffd9f | 1153 | |
519ef046 LP |
1154 | fd = dns_scope_socket_udp(t->scope, t->server, 53); |
1155 | if (fd < 0) | |
1156 | return fd; | |
1157 | ||
1158 | r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); | |
1159 | if (r < 0) { | |
1160 | safe_close(fd); | |
1161 | return r; | |
1162 | } | |
1163 | ||
aa4a9deb | 1164 | (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); |
519ef046 LP |
1165 | t->dns_udp_fd = fd; |
1166 | } | |
1167 | ||
274b8748 | 1168 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
1169 | if (r < 0) |
1170 | return r; | |
1171 | } else | |
1172 | dns_transaction_close_connection(t); | |
1173 | ||
1174 | r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); | |
471d40d9 TG |
1175 | if (r < 0) |
1176 | return r; | |
c19ffd9f | 1177 | |
519ef046 | 1178 | dns_transaction_reset_answer(t); |
be808ea0 | 1179 | |
471d40d9 | 1180 | return 0; |
c19ffd9f TG |
1181 | } |
1182 | ||
ec2c5e43 LP |
1183 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { |
1184 | DnsTransaction *t = userdata; | |
ec2c5e43 LP |
1185 | |
1186 | assert(s); | |
1187 | assert(t); | |
1188 | ||
ef7ce6df DM |
1189 | if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { |
1190 | /* Timeout reached? Increase the timeout for the server used */ | |
1191 | switch (t->scope->protocol) { | |
49cce12d | 1192 | |
ef7ce6df DM |
1193 | case DNS_PROTOCOL_DNS: |
1194 | assert(t->server); | |
274b8748 | 1195 | dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level, usec - t->start_usec); |
ef7ce6df | 1196 | break; |
49cce12d | 1197 | |
ef7ce6df DM |
1198 | case DNS_PROTOCOL_LLMNR: |
1199 | case DNS_PROTOCOL_MDNS: | |
1200 | dns_scope_packet_lost(t->scope, usec - t->start_usec); | |
ef7ce6df | 1201 | break; |
49cce12d | 1202 | |
ef7ce6df DM |
1203 | default: |
1204 | assert_not_reached("Invalid DNS protocol."); | |
1205 | } | |
1206 | ||
1207 | if (t->initial_jitter_scheduled) | |
1208 | t->initial_jitter_elapsed = true; | |
be808ea0 TG |
1209 | } |
1210 | ||
423659ab LP |
1211 | log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); |
1212 | ||
d001e0a3 | 1213 | dns_transaction_retry(t, true); |
ec2c5e43 LP |
1214 | return 0; |
1215 | } | |
1216 | ||
9df3ba6c TG |
1217 | static usec_t transaction_get_resend_timeout(DnsTransaction *t) { |
1218 | assert(t); | |
1219 | assert(t->scope); | |
1220 | ||
dc349f5f | 1221 | |
9df3ba6c | 1222 | switch (t->scope->protocol) { |
49cce12d | 1223 | |
9df3ba6c | 1224 | case DNS_PROTOCOL_DNS: |
dc349f5f LP |
1225 | |
1226 | /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly | |
1227 | * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that | |
1228 | * needlessly. */ | |
1229 | if (t->stream) | |
1230 | return TRANSACTION_TCP_TIMEOUT_USEC; | |
1231 | ||
9df3ba6c | 1232 | assert(t->server); |
9df3ba6c | 1233 | return t->server->resend_timeout; |
49cce12d | 1234 | |
9df3ba6c | 1235 | case DNS_PROTOCOL_MDNS: |
11a27c2e | 1236 | assert(t->n_attempts > 0); |
53fda2bb DR |
1237 | if (t->probing) |
1238 | return MDNS_PROBING_INTERVAL_USEC; | |
1239 | else | |
1240 | return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; | |
49cce12d | 1241 | |
11a27c2e | 1242 | case DNS_PROTOCOL_LLMNR: |
9df3ba6c | 1243 | return t->scope->resend_timeout; |
49cce12d | 1244 | |
9df3ba6c TG |
1245 | default: |
1246 | assert_not_reached("Invalid DNS protocol."); | |
1247 | } | |
1248 | } | |
1249 | ||
c842ff24 | 1250 | static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { |
ec2c5e43 LP |
1251 | int r; |
1252 | ||
1253 | assert(t); | |
1254 | ||
f535705a | 1255 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 1256 | |
edbcc1fd LP |
1257 | r = dns_scope_network_good(t->scope); |
1258 | if (r < 0) | |
1259 | return r; | |
1260 | if (r == 0) { | |
1261 | dns_transaction_complete(t, DNS_TRANSACTION_NETWORK_DOWN); | |
1262 | return 0; | |
1263 | } | |
1264 | ||
ec2c5e43 LP |
1265 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { |
1266 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1267 | return 0; | |
1268 | } | |
1269 | ||
cbe4216d | 1270 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { |
ec2c5e43 LP |
1271 | /* If we already tried via a stream, then we don't |
1272 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
1273 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1274 | return 0; | |
1275 | } | |
1276 | ||
1277 | t->n_attempts++; | |
9df3ba6c | 1278 | t->start_usec = ts; |
c61d2b44 LP |
1279 | |
1280 | dns_transaction_reset_answer(t); | |
c5b4f861 | 1281 | dns_transaction_flush_dnssec_transactions(t); |
ec2c5e43 | 1282 | |
0d2cd476 LP |
1283 | /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ |
1284 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
8e54f5d9 | 1285 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); |
0d2cd476 LP |
1286 | if (r < 0) |
1287 | return r; | |
1288 | if (r > 0) { | |
1289 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1290 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
931851e8 | 1291 | t->answer_authenticated = true; |
0d2cd476 LP |
1292 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1293 | return 0; | |
1294 | } | |
b2b796b8 | 1295 | |
1c02e7ba | 1296 | if (dns_name_is_root(dns_resource_key_name(t->key)) && |
b2b796b8 LP |
1297 | t->key->type == DNS_TYPE_DS) { |
1298 | ||
1299 | /* Hmm, this is a request for the root DS? A | |
1300 | * DS RR doesn't exist in the root zone, and | |
1301 | * if our trust anchor didn't know it either, | |
1302 | * this means we cannot do any DNSSEC logic | |
1303 | * anymore. */ | |
1304 | ||
1ed8c0fb | 1305 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
b2b796b8 LP |
1306 | /* We are in downgrade mode. In this |
1307 | * case, synthesize an unsigned empty | |
1308 | * response, so that the any lookup | |
1309 | * depending on this one can continue | |
1310 | * assuming there was no DS, and hence | |
1311 | * the root zone was unsigned. */ | |
1312 | ||
1313 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1314 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
1315 | t->answer_authenticated = false; | |
1316 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
1317 | } else | |
1318 | /* If we are not in downgrade mode, | |
1319 | * then fail the lookup, because we | |
1320 | * cannot reasonably answer it. There | |
1321 | * might be DS RRs, but we don't know | |
1322 | * them, and the DNS server won't tell | |
1323 | * them to us (and even if it would, | |
202b76ae | 1324 | * we couldn't validate and trust them. */ |
b2b796b8 LP |
1325 | dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); |
1326 | ||
1327 | return 0; | |
1328 | } | |
0d2cd476 LP |
1329 | } |
1330 | ||
1331 | /* Check the zone, but only if this transaction is not used | |
d746bb3e | 1332 | * for probing or verifying a zone item. */ |
547973de | 1333 | if (set_isempty(t->notify_zone_items)) { |
d746bb3e | 1334 | |
97ebebbc | 1335 | r = dns_zone_lookup(&t->scope->zone, t->key, dns_scope_ifindex(t->scope), &t->answer, NULL, NULL); |
d746bb3e LP |
1336 | if (r < 0) |
1337 | return r; | |
1338 | if (r > 0) { | |
ae6a4bbf | 1339 | t->answer_rcode = DNS_RCODE_SUCCESS; |
c3bc53e6 | 1340 | t->answer_source = DNS_TRANSACTION_ZONE; |
931851e8 | 1341 | t->answer_authenticated = true; |
d746bb3e LP |
1342 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1343 | return 0; | |
1344 | } | |
1345 | } | |
1346 | ||
4d926a69 LP |
1347 | /* Check the cache, but only if this transaction is not used |
1348 | * for probing or verifying a zone item. */ | |
547973de | 1349 | if (set_isempty(t->notify_zone_items)) { |
2c27fbca | 1350 | |
4d926a69 LP |
1351 | /* Before trying the cache, let's make sure we figured out a |
1352 | * server to use. Should this cause a change of server this | |
1353 | * might flush the cache. */ | |
1354 | dns_scope_get_dns_server(t->scope); | |
2c27fbca | 1355 | |
4d926a69 LP |
1356 | /* Let's then prune all outdated entries */ |
1357 | dns_cache_prune(&t->scope->cache); | |
1358 | ||
17c8de63 | 1359 | r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); |
4d926a69 LP |
1360 | if (r < 0) |
1361 | return r; | |
1362 | if (r > 0) { | |
c3bc53e6 | 1363 | t->answer_source = DNS_TRANSACTION_CACHE; |
ae6a4bbf | 1364 | if (t->answer_rcode == DNS_RCODE_SUCCESS) |
4d926a69 LP |
1365 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1366 | else | |
3bbdc31d | 1367 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
4d926a69 LP |
1368 | return 0; |
1369 | } | |
ec2c5e43 LP |
1370 | } |
1371 | ||
1effe965 DM |
1372 | return 1; |
1373 | } | |
1374 | ||
0afa57e2 DM |
1375 | static int dns_transaction_make_packet_mdns(DnsTransaction *t) { |
1376 | ||
1377 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
7778dfff | 1378 | bool add_known_answers = false; |
0afa57e2 DM |
1379 | DnsTransaction *other; |
1380 | unsigned qdcount; | |
1381 | usec_t ts; | |
1382 | int r; | |
1383 | ||
1384 | assert(t); | |
1385 | assert(t->scope->protocol == DNS_PROTOCOL_MDNS); | |
1386 | ||
e5abebab | 1387 | /* Discard any previously prepared packet, so we can start over and coalesce again */ |
0afa57e2 DM |
1388 | t->sent = dns_packet_unref(t->sent); |
1389 | ||
1390 | r = dns_packet_new_query(&p, t->scope->protocol, 0, false); | |
1391 | if (r < 0) | |
1392 | return r; | |
1393 | ||
58ab31d5 | 1394 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1395 | if (r < 0) |
1396 | return r; | |
1397 | ||
1398 | qdcount = 1; | |
1399 | ||
7778dfff DM |
1400 | if (dns_key_is_shared(t->key)) |
1401 | add_known_answers = true; | |
1402 | ||
0afa57e2 DM |
1403 | /* |
1404 | * For mDNS, we want to coalesce as many open queries in pending transactions into one single | |
1405 | * query packet on the wire as possible. To achieve that, we iterate through all pending transactions | |
1406 | * in our current scope, and see whether their timing contraints allow them to be sent. | |
1407 | */ | |
1408 | ||
1409 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
1410 | ||
1411 | LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { | |
1412 | ||
1413 | /* Skip ourselves */ | |
1414 | if (other == t) | |
1415 | continue; | |
1416 | ||
1417 | if (other->state != DNS_TRANSACTION_PENDING) | |
1418 | continue; | |
1419 | ||
1420 | if (other->next_attempt_after > ts) | |
1421 | continue; | |
1422 | ||
1423 | if (qdcount >= UINT16_MAX) | |
1424 | break; | |
1425 | ||
58ab31d5 | 1426 | r = dns_packet_append_key(p, other->key, 0, NULL); |
0afa57e2 DM |
1427 | |
1428 | /* | |
1429 | * If we can't stuff more questions into the packet, just give up. | |
1430 | * One of the 'other' transactions will fire later and take care of the rest. | |
1431 | */ | |
1432 | if (r == -EMSGSIZE) | |
1433 | break; | |
1434 | ||
1435 | if (r < 0) | |
1436 | return r; | |
1437 | ||
c842ff24 | 1438 | r = dns_transaction_prepare(other, ts); |
0afa57e2 DM |
1439 | if (r <= 0) |
1440 | continue; | |
1441 | ||
1442 | ts += transaction_get_resend_timeout(other); | |
1443 | ||
1444 | r = sd_event_add_time( | |
1445 | other->scope->manager->event, | |
1446 | &other->timeout_event_source, | |
1447 | clock_boottime_or_monotonic(), | |
1448 | ts, 0, | |
1449 | on_transaction_timeout, other); | |
1450 | if (r < 0) | |
1451 | return r; | |
1452 | ||
ff537038 | 1453 | (void) sd_event_source_set_description(other->timeout_event_source, "dns-transaction-timeout"); |
aa4a9deb | 1454 | |
0afa57e2 DM |
1455 | other->state = DNS_TRANSACTION_PENDING; |
1456 | other->next_attempt_after = ts; | |
1457 | ||
313cefa1 | 1458 | qdcount++; |
7778dfff DM |
1459 | |
1460 | if (dns_key_is_shared(other->key)) | |
1461 | add_known_answers = true; | |
0afa57e2 DM |
1462 | } |
1463 | ||
1464 | DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); | |
0afa57e2 | 1465 | |
7778dfff DM |
1466 | /* Append known answer section if we're asking for any shared record */ |
1467 | if (add_known_answers) { | |
1468 | r = dns_cache_export_shared_to_packet(&t->scope->cache, p); | |
1469 | if (r < 0) | |
1470 | return r; | |
1471 | } | |
1472 | ||
0afa57e2 DM |
1473 | t->sent = p; |
1474 | p = NULL; | |
1475 | ||
1476 | return 0; | |
1477 | } | |
1478 | ||
1479 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
1480 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1481 | int r; | |
1482 | ||
1483 | assert(t); | |
1484 | ||
1485 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) | |
1486 | return dns_transaction_make_packet_mdns(t); | |
1487 | ||
1488 | if (t->sent) | |
1489 | return 0; | |
1490 | ||
b652d4a2 | 1491 | r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); |
0afa57e2 DM |
1492 | if (r < 0) |
1493 | return r; | |
1494 | ||
58ab31d5 | 1495 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1496 | if (r < 0) |
1497 | return r; | |
1498 | ||
1499 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
1500 | DNS_PACKET_HEADER(p)->id = t->id; | |
1501 | ||
1502 | t->sent = p; | |
1503 | p = NULL; | |
1504 | ||
1505 | return 0; | |
1506 | } | |
1507 | ||
1effe965 DM |
1508 | int dns_transaction_go(DnsTransaction *t) { |
1509 | usec_t ts; | |
1510 | int r; | |
202b76ae | 1511 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
1effe965 DM |
1512 | |
1513 | assert(t); | |
1514 | ||
5278bbfe LP |
1515 | /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished |
1516 | * now. */ | |
1517 | ||
1effe965 | 1518 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
547973de | 1519 | |
c842ff24 | 1520 | r = dns_transaction_prepare(t, ts); |
1effe965 DM |
1521 | if (r <= 0) |
1522 | return r; | |
1523 | ||
202b76ae | 1524 | log_debug("Transaction %" PRIu16 " for <%s> scope %s on %s/%s.", |
a5784c49 | 1525 | t->id, |
202b76ae | 1526 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
a5784c49 LP |
1527 | dns_protocol_to_string(t->scope->protocol), |
1528 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 1529 | af_to_name_short(t->scope->family)); |
1effe965 | 1530 | |
ef7ce6df | 1531 | if (!t->initial_jitter_scheduled && |
3742095b | 1532 | IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
ea12bcc7 | 1533 | usec_t jitter, accuracy; |
6e068472 LP |
1534 | |
1535 | /* RFC 4795 Section 2.7 suggests all queries should be | |
1536 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
1537 | ||
ef7ce6df | 1538 | t->initial_jitter_scheduled = true; |
6e068472 LP |
1539 | |
1540 | random_bytes(&jitter, sizeof(jitter)); | |
ea12bcc7 DM |
1541 | |
1542 | switch (t->scope->protocol) { | |
519ef046 | 1543 | |
ea12bcc7 DM |
1544 | case DNS_PROTOCOL_LLMNR: |
1545 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
1546 | accuracy = LLMNR_JITTER_INTERVAL_USEC; | |
1547 | break; | |
519ef046 | 1548 | |
ea12bcc7 DM |
1549 | case DNS_PROTOCOL_MDNS: |
1550 | jitter %= MDNS_JITTER_RANGE_USEC; | |
1551 | jitter += MDNS_JITTER_MIN_USEC; | |
1552 | accuracy = MDNS_JITTER_RANGE_USEC; | |
1553 | break; | |
1554 | default: | |
1555 | assert_not_reached("bad protocol"); | |
1556 | } | |
6e068472 LP |
1557 | |
1558 | r = sd_event_add_time( | |
1559 | t->scope->manager->event, | |
1560 | &t->timeout_event_source, | |
1561 | clock_boottime_or_monotonic(), | |
ea12bcc7 | 1562 | ts + jitter, accuracy, |
6e068472 LP |
1563 | on_transaction_timeout, t); |
1564 | if (r < 0) | |
1565 | return r; | |
1566 | ||
aa4a9deb LP |
1567 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1568 | ||
6e068472 | 1569 | t->n_attempts = 0; |
a9da14e1 | 1570 | t->next_attempt_after = ts; |
6e068472 LP |
1571 | t->state = DNS_TRANSACTION_PENDING; |
1572 | ||
ea12bcc7 | 1573 | log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); |
6e068472 LP |
1574 | return 0; |
1575 | } | |
1576 | ||
ec2c5e43 LP |
1577 | /* Otherwise, we need to ask the network */ |
1578 | r = dns_transaction_make_packet(t); | |
ec2c5e43 LP |
1579 | if (r < 0) |
1580 | return r; | |
1581 | ||
1582 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
1c02e7ba ZJS |
1583 | (dns_name_endswith(dns_resource_key_name(t->key), "in-addr.arpa") > 0 || |
1584 | dns_name_endswith(dns_resource_key_name(t->key), "ip6.arpa") > 0)) { | |
ec2c5e43 LP |
1585 | |
1586 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
1587 | * always be made via TCP on LLMNR */ | |
1588 | r = dns_transaction_open_tcp(t); | |
1589 | } else { | |
be808ea0 TG |
1590 | /* Try via UDP, and if that fails due to large size or lack of |
1591 | * support try via TCP */ | |
49cce12d | 1592 | r = dns_transaction_emit_udp(t); |
29ab0552 LP |
1593 | if (r == -EMSGSIZE) |
1594 | log_debug("Sending query via TCP since it is too large."); | |
dc349f5f | 1595 | else if (r == -EAGAIN) |
034e8031 | 1596 | log_debug("Sending query via TCP since server doesn't support UDP."); |
4c701096 | 1597 | if (IN_SET(r, -EMSGSIZE, -EAGAIN)) |
ec2c5e43 LP |
1598 | r = dns_transaction_open_tcp(t); |
1599 | } | |
be808ea0 | 1600 | |
ec2c5e43 LP |
1601 | if (r == -ESRCH) { |
1602 | /* No servers to send this to? */ | |
1603 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1604 | return 0; | |
91adc4db LP |
1605 | } |
1606 | if (r == -EOPNOTSUPP) { | |
1607 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1608 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1609 | return 0; | |
1610 | } | |
0791110f | 1611 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(-r)) { |
e94968ba | 1612 | /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot |
0791110f LP |
1613 | * answer this request with this protocol. */ |
1614 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
1615 | return 0; | |
1616 | } | |
91adc4db | 1617 | if (r < 0) { |
7cc6ed7b LP |
1618 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1619 | return r; | |
13b551ac | 1620 | |
ec2c5e43 | 1621 | /* Couldn't send? Try immediately again, with a new server */ |
519ef046 | 1622 | dns_scope_next_dns_server(t->scope); |
ec2c5e43 LP |
1623 | |
1624 | return dns_transaction_go(t); | |
1625 | } | |
1626 | ||
a9da14e1 DM |
1627 | ts += transaction_get_resend_timeout(t); |
1628 | ||
9a015429 LP |
1629 | r = sd_event_add_time( |
1630 | t->scope->manager->event, | |
1631 | &t->timeout_event_source, | |
1632 | clock_boottime_or_monotonic(), | |
a9da14e1 | 1633 | ts, 0, |
9a015429 | 1634 | on_transaction_timeout, t); |
ec2c5e43 LP |
1635 | if (r < 0) |
1636 | return r; | |
1637 | ||
aa4a9deb LP |
1638 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1639 | ||
ec2c5e43 | 1640 | t->state = DNS_TRANSACTION_PENDING; |
a9da14e1 DM |
1641 | t->next_attempt_after = ts; |
1642 | ||
ec2c5e43 LP |
1643 | return 1; |
1644 | } | |
1645 | ||
f2992dc1 LP |
1646 | static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { |
1647 | DnsTransaction *n; | |
1648 | Iterator i; | |
1649 | int r; | |
1650 | ||
1651 | assert(t); | |
1652 | assert(aux); | |
1653 | ||
1654 | /* Try to find cyclic dependencies between transaction objects */ | |
1655 | ||
1656 | if (t == aux) | |
1657 | return 1; | |
1658 | ||
3eb6aa00 | 1659 | SET_FOREACH(n, aux->dnssec_transactions, i) { |
f2992dc1 LP |
1660 | r = dns_transaction_find_cyclic(t, n); |
1661 | if (r != 0) | |
1662 | return r; | |
1663 | } | |
1664 | ||
3eb6aa00 | 1665 | return 0; |
f2992dc1 LP |
1666 | } |
1667 | ||
547973de LP |
1668 | static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { |
1669 | DnsTransaction *aux; | |
1670 | int r; | |
1671 | ||
1672 | assert(t); | |
1673 | assert(ret); | |
1674 | assert(key); | |
1675 | ||
1676 | aux = dns_scope_find_transaction(t->scope, key, true); | |
1677 | if (!aux) { | |
1678 | r = dns_transaction_new(&aux, t->scope, key); | |
1679 | if (r < 0) | |
1680 | return r; | |
1681 | } else { | |
1682 | if (set_contains(t->dnssec_transactions, aux)) { | |
1683 | *ret = aux; | |
1684 | return 0; | |
1685 | } | |
f2992dc1 LP |
1686 | |
1687 | r = dns_transaction_find_cyclic(t, aux); | |
1688 | if (r < 0) | |
1689 | return r; | |
1690 | if (r > 0) { | |
202b76ae ZJS |
1691 | char s[DNS_RESOURCE_KEY_STRING_MAX], saux[DNS_RESOURCE_KEY_STRING_MAX]; |
1692 | ||
1693 | log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", | |
f2992dc1 | 1694 | aux->id, |
202b76ae | 1695 | dns_resource_key_to_string(t->key, s, sizeof s), |
f2992dc1 | 1696 | t->id, |
202b76ae ZJS |
1697 | dns_resource_key_to_string(aux->key, saux, sizeof saux)); |
1698 | ||
f2992dc1 LP |
1699 | return -ELOOP; |
1700 | } | |
547973de LP |
1701 | } |
1702 | ||
1703 | r = set_ensure_allocated(&t->dnssec_transactions, NULL); | |
1704 | if (r < 0) | |
1705 | goto gc; | |
1706 | ||
1707 | r = set_ensure_allocated(&aux->notify_transactions, NULL); | |
1708 | if (r < 0) | |
35aa04e9 LP |
1709 | goto gc; |
1710 | ||
1711 | r = set_ensure_allocated(&aux->notify_transactions_done, NULL); | |
1712 | if (r < 0) | |
547973de LP |
1713 | goto gc; |
1714 | ||
1715 | r = set_put(t->dnssec_transactions, aux); | |
1716 | if (r < 0) | |
1717 | goto gc; | |
1718 | ||
1719 | r = set_put(aux->notify_transactions, t); | |
1720 | if (r < 0) { | |
1721 | (void) set_remove(t->dnssec_transactions, aux); | |
1722 | goto gc; | |
1723 | } | |
1724 | ||
1725 | *ret = aux; | |
1726 | return 1; | |
1727 | ||
1728 | gc: | |
1729 | dns_transaction_gc(aux); | |
1730 | return r; | |
1731 | } | |
1732 | ||
1733 | static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { | |
1734 | _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; | |
1735 | DnsTransaction *aux; | |
1736 | int r; | |
1737 | ||
1738 | assert(t); | |
1739 | assert(key); | |
1740 | ||
1741 | /* Try to get the data from the trust anchor */ | |
8e54f5d9 | 1742 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); |
547973de LP |
1743 | if (r < 0) |
1744 | return r; | |
1745 | if (r > 0) { | |
1746 | r = dns_answer_extend(&t->validated_keys, a); | |
1747 | if (r < 0) | |
1748 | return r; | |
1749 | ||
1750 | return 0; | |
1751 | } | |
1752 | ||
1753 | /* This didn't work, ask for it via the network/cache then. */ | |
1754 | r = dns_transaction_add_dnssec_transaction(t, key, &aux); | |
f2992dc1 LP |
1755 | if (r == -ELOOP) /* This would result in a cyclic dependency */ |
1756 | return 0; | |
547973de LP |
1757 | if (r < 0) |
1758 | return r; | |
1759 | ||
1760 | if (aux->state == DNS_TRANSACTION_NULL) { | |
1761 | r = dns_transaction_go(aux); | |
1762 | if (r < 0) | |
1763 | return r; | |
1764 | } | |
1765 | ||
f2992dc1 | 1766 | return 1; |
547973de LP |
1767 | } |
1768 | ||
8a516214 LP |
1769 | static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { |
1770 | int r; | |
1771 | ||
1772 | assert(t); | |
1773 | ||
c629ff58 | 1774 | /* Check whether the specified name is in the NTA |
8a516214 LP |
1775 | * database, either in the global one, or the link-local |
1776 | * one. */ | |
1777 | ||
1778 | r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); | |
1779 | if (r != 0) | |
1780 | return r; | |
1781 | ||
1782 | if (!t->scope->link) | |
1783 | return 0; | |
1784 | ||
1785 | return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); | |
1786 | } | |
1787 | ||
105e1512 LP |
1788 | static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { |
1789 | int r; | |
1790 | ||
1791 | assert(t); | |
1792 | ||
1793 | /* Checks whether the answer is negative, and lacks NSEC/NSEC3 | |
1794 | * RRs to prove it */ | |
1795 | ||
1796 | r = dns_transaction_has_positive_answer(t, NULL); | |
1797 | if (r < 0) | |
1798 | return r; | |
1799 | if (r > 0) | |
1800 | return false; | |
1801 | ||
8e54f5d9 LP |
1802 | /* Is this key explicitly listed as a negative trust anchor? |
1803 | * If so, it's nothing we need to care about */ | |
1c02e7ba | 1804 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
1805 | if (r < 0) |
1806 | return r; | |
1807 | if (r > 0) | |
1808 | return false; | |
1809 | ||
105e1512 LP |
1810 | /* The answer does not contain any RRs that match to the |
1811 | * question. If so, let's see if there are any NSEC/NSEC3 RRs | |
1812 | * included. If not, the answer is unsigned. */ | |
1813 | ||
1814 | r = dns_answer_contains_nsec_or_nsec3(t->answer); | |
1815 | if (r < 0) | |
1816 | return r; | |
1817 | if (r > 0) | |
1818 | return false; | |
1819 | ||
1820 | return true; | |
1821 | } | |
1822 | ||
1823 | static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { | |
1824 | int r; | |
1825 | ||
1826 | assert(t); | |
1827 | assert(rr); | |
1828 | ||
1829 | /* Check if the specified RR is the "primary" response, | |
1830 | * i.e. either matches the question precisely or is a | |
4cb94977 | 1831 | * CNAME/DNAME for it. */ |
105e1512 LP |
1832 | |
1833 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1834 | if (r != 0) | |
1835 | return r; | |
1836 | ||
4cb94977 | 1837 | return dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); |
105e1512 LP |
1838 | } |
1839 | ||
92ec902a LP |
1840 | static bool dns_transaction_dnssec_supported(DnsTransaction *t) { |
1841 | assert(t); | |
1842 | ||
1843 | /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon | |
1844 | * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ | |
1845 | ||
1846 | if (t->scope->protocol != DNS_PROTOCOL_DNS) | |
1847 | return false; | |
1848 | ||
1849 | /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well | |
1850 | * be supported, hence return true. */ | |
1851 | if (!t->server) | |
1852 | return true; | |
1853 | ||
d001e0a3 LP |
1854 | /* Note that we do not check the feature level actually used for the transaction but instead the feature level |
1855 | * the server is known to support currently, as the transaction feature level might be lower than what the | |
1856 | * server actually supports, since we might have downgraded this transaction's feature level because we got a | |
1857 | * SERVFAIL earlier and wanted to check whether downgrading fixes it. */ | |
92ec902a LP |
1858 | |
1859 | return dns_server_dnssec_supported(t->server); | |
1860 | } | |
1861 | ||
1862 | static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { | |
1863 | DnsTransaction *dt; | |
1864 | Iterator i; | |
1865 | ||
1866 | assert(t); | |
1867 | ||
1868 | /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ | |
1869 | ||
1870 | if (!dns_transaction_dnssec_supported(t)) | |
1871 | return false; | |
1872 | ||
1873 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
1874 | if (!dns_transaction_dnssec_supported(dt)) | |
1875 | return false; | |
1876 | ||
1877 | return true; | |
1878 | } | |
1879 | ||
547973de LP |
1880 | int dns_transaction_request_dnssec_keys(DnsTransaction *t) { |
1881 | DnsResourceRecord *rr; | |
105e1512 | 1882 | |
547973de LP |
1883 | int r; |
1884 | ||
1885 | assert(t); | |
1886 | ||
105e1512 LP |
1887 | /* |
1888 | * Retrieve all auxiliary RRs for the answer we got, so that | |
1889 | * we can verify signatures or prove that RRs are rightfully | |
1890 | * unsigned. Specifically: | |
1891 | * | |
1892 | * - For RRSIG we get the matching DNSKEY | |
1893 | * - For DNSKEY we get the matching DS | |
1894 | * - For unsigned SOA/NS we get the matching DS | |
b63fca62 | 1895 | * - For unsigned CNAME/DNAME/DS we get the parent SOA RR |
105e1512 | 1896 | * - For other unsigned RRs we get the matching SOA RR |
4bbc06cc LP |
1897 | * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR |
1898 | * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR | |
105e1512 LP |
1899 | * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR |
1900 | */ | |
1901 | ||
b652d4a2 | 1902 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de | 1903 | return 0; |
92ec902a LP |
1904 | if (t->answer_source != DNS_TRANSACTION_NETWORK) |
1905 | return 0; /* We only need to validate stuff from the network */ | |
1906 | if (!dns_transaction_dnssec_supported(t)) | |
1907 | return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */ | |
b652d4a2 | 1908 | |
547973de LP |
1909 | DNS_ANSWER_FOREACH(rr, t->answer) { |
1910 | ||
105e1512 LP |
1911 | if (dns_type_is_pseudo(rr->key->type)) |
1912 | continue; | |
1913 | ||
8e54f5d9 | 1914 | /* If this RR is in the negative trust anchor, we don't need to validate it. */ |
1c02e7ba | 1915 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
1916 | if (r < 0) |
1917 | return r; | |
1918 | if (r > 0) | |
1919 | continue; | |
1920 | ||
547973de LP |
1921 | switch (rr->key->type) { |
1922 | ||
1923 | case DNS_TYPE_RRSIG: { | |
1924 | /* For each RRSIG we request the matching DNSKEY */ | |
1925 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; | |
1926 | ||
1927 | /* If this RRSIG is about a DNSKEY RR and the | |
1928 | * signer is the same as the owner, then we | |
1929 | * already have the DNSKEY, and we don't have | |
1930 | * to look for more. */ | |
1931 | if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { | |
1c02e7ba | 1932 | r = dns_name_equal(rr->rrsig.signer, dns_resource_key_name(rr->key)); |
547973de LP |
1933 | if (r < 0) |
1934 | return r; | |
1935 | if (r > 0) | |
1936 | continue; | |
1937 | } | |
1938 | ||
105e1512 LP |
1939 | /* If the signer is not a parent of our |
1940 | * original query, then this is about an | |
1941 | * auxiliary RRset, but not anything we asked | |
1942 | * for. In this case we aren't interested, | |
1943 | * because we don't want to request additional | |
1944 | * RRs for stuff we didn't really ask for, and | |
1945 | * also to avoid request loops, where | |
1946 | * additional RRs from one transaction result | |
1947 | * in another transaction whose additonal RRs | |
1948 | * point back to the original transaction, and | |
1949 | * we deadlock. */ | |
1c02e7ba | 1950 | r = dns_name_endswith(dns_resource_key_name(t->key), rr->rrsig.signer); |
547973de LP |
1951 | if (r < 0) |
1952 | return r; | |
1953 | if (r == 0) | |
1954 | continue; | |
1955 | ||
1956 | dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); | |
1957 | if (!dnskey) | |
1958 | return -ENOMEM; | |
1959 | ||
1c02e7ba ZJS |
1960 | log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", |
1961 | t->id, dns_resource_key_name(rr->key), rr->rrsig.key_tag); | |
547973de LP |
1962 | r = dns_transaction_request_dnssec_rr(t, dnskey); |
1963 | if (r < 0) | |
1964 | return r; | |
1965 | break; | |
1966 | } | |
1967 | ||
1968 | case DNS_TYPE_DNSKEY: { | |
1969 | /* For each DNSKEY we request the matching DS */ | |
1970 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
1971 | ||
105e1512 LP |
1972 | /* If the DNSKEY we are looking at is not for |
1973 | * zone we are interested in, nor any of its | |
1974 | * parents, we aren't interested, and don't | |
1975 | * request it. After all, we don't want to end | |
1976 | * up in request loops, and want to keep | |
1977 | * additional traffic down. */ | |
1978 | ||
1c02e7ba | 1979 | r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
1980 | if (r < 0) |
1981 | return r; | |
1982 | if (r == 0) | |
1983 | continue; | |
1984 | ||
1c02e7ba | 1985 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
547973de LP |
1986 | if (!ds) |
1987 | return -ENOMEM; | |
1988 | ||
1c02e7ba ZJS |
1989 | log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", |
1990 | t->id, dns_resource_key_name(rr->key), dnssec_keytag(rr, false)); | |
105e1512 LP |
1991 | r = dns_transaction_request_dnssec_rr(t, ds); |
1992 | if (r < 0) | |
1993 | return r; | |
547973de | 1994 | |
105e1512 LP |
1995 | break; |
1996 | } | |
1997 | ||
105e1512 LP |
1998 | case DNS_TYPE_SOA: |
1999 | case DNS_TYPE_NS: { | |
2000 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2001 | ||
2002 | /* For an unsigned SOA or NS, try to acquire | |
2003 | * the matching DS RR, as we are at a zone cut | |
2004 | * then, and whether a DS exists tells us | |
2005 | * whether the zone is signed. Do so only if | |
2006 | * this RR matches our original question, | |
2007 | * however. */ | |
2008 | ||
2009 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
2010 | if (r < 0) | |
2011 | return r; | |
6993d264 LP |
2012 | if (r == 0) { |
2013 | /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is | |
2014 | * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry? | |
2015 | * If so, we need to validate it, too. */ | |
2016 | ||
2017 | r = dns_answer_match_key(t->answer, t->key, NULL); | |
2018 | if (r < 0) | |
2019 | return r; | |
2020 | if (r > 0) /* positive reply, we won't need the SOA and hence don't need to validate | |
2021 | * it. */ | |
2022 | continue; | |
2023 | } | |
105e1512 LP |
2024 | |
2025 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2026 | if (r < 0) | |
2027 | return r; | |
2028 | if (r > 0) | |
2029 | continue; | |
2030 | ||
1c02e7ba | 2031 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
105e1512 LP |
2032 | if (!ds) |
2033 | return -ENOMEM; | |
2034 | ||
1c02e7ba ZJS |
2035 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", |
2036 | t->id, dns_resource_key_name(rr->key)); | |
547973de LP |
2037 | r = dns_transaction_request_dnssec_rr(t, ds); |
2038 | if (r < 0) | |
2039 | return r; | |
2040 | ||
2041 | break; | |
105e1512 LP |
2042 | } |
2043 | ||
b63fca62 | 2044 | case DNS_TYPE_DS: |
105e1512 LP |
2045 | case DNS_TYPE_CNAME: |
2046 | case DNS_TYPE_DNAME: { | |
2047 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2048 | const char *name; | |
2049 | ||
2050 | /* CNAMEs and DNAMEs cannot be located at a | |
2051 | * zone apex, hence ask for the parent SOA for | |
2052 | * unsigned CNAME/DNAME RRs, maybe that's the | |
2053 | * apex. But do all that only if this is | |
2054 | * actually a response to our original | |
b63fca62 LP |
2055 | * question. |
2056 | * | |
2057 | * Similar for DS RRs, which are signed when | |
2058 | * the parent SOA is signed. */ | |
105e1512 LP |
2059 | |
2060 | r = dns_transaction_is_primary_response(t, rr); | |
2061 | if (r < 0) | |
2062 | return r; | |
2063 | if (r == 0) | |
2064 | continue; | |
2065 | ||
2066 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2067 | if (r < 0) | |
2068 | return r; | |
2069 | if (r > 0) | |
2070 | continue; | |
2071 | ||
43e6779a LP |
2072 | r = dns_answer_has_dname_for_cname(t->answer, rr); |
2073 | if (r < 0) | |
2074 | return r; | |
2075 | if (r > 0) | |
2076 | continue; | |
2077 | ||
1c02e7ba | 2078 | name = dns_resource_key_name(rr->key); |
105e1512 LP |
2079 | r = dns_name_parent(&name); |
2080 | if (r < 0) | |
2081 | return r; | |
2082 | if (r == 0) | |
2083 | continue; | |
2084 | ||
2085 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); | |
2086 | if (!soa) | |
2087 | return -ENOMEM; | |
2088 | ||
1c02e7ba ZJS |
2089 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", |
2090 | t->id, dns_resource_key_name(rr->key)); | |
105e1512 LP |
2091 | r = dns_transaction_request_dnssec_rr(t, soa); |
2092 | if (r < 0) | |
2093 | return r; | |
2094 | ||
2095 | break; | |
2096 | } | |
2097 | ||
2098 | default: { | |
2099 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2100 | ||
b63fca62 LP |
2101 | /* For other unsigned RRsets (including |
2102 | * NSEC/NSEC3!), look for proof the zone is | |
2103 | * unsigned, by requesting the SOA RR of the | |
2104 | * zone. However, do so only if they are | |
2105 | * directly relevant to our original | |
105e1512 LP |
2106 | * question. */ |
2107 | ||
2108 | r = dns_transaction_is_primary_response(t, rr); | |
2109 | if (r < 0) | |
2110 | return r; | |
2111 | if (r == 0) | |
2112 | continue; | |
2113 | ||
2114 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2115 | if (r < 0) | |
2116 | return r; | |
2117 | if (r > 0) | |
2118 | continue; | |
2119 | ||
1c02e7ba | 2120 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, dns_resource_key_name(rr->key)); |
105e1512 LP |
2121 | if (!soa) |
2122 | return -ENOMEM; | |
2123 | ||
1c02e7ba ZJS |
2124 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", |
2125 | t->id, dns_resource_key_name(rr->key), dns_resource_record_to_string(rr)); | |
105e1512 LP |
2126 | r = dns_transaction_request_dnssec_rr(t, soa); |
2127 | if (r < 0) | |
2128 | return r; | |
2129 | break; | |
547973de LP |
2130 | }} |
2131 | } | |
2132 | ||
105e1512 LP |
2133 | /* Above, we requested everything necessary to validate what |
2134 | * we got. Now, let's request what we need to validate what we | |
2135 | * didn't get... */ | |
2136 | ||
2137 | r = dns_transaction_has_unsigned_negative_answer(t); | |
2138 | if (r < 0) | |
2139 | return r; | |
2140 | if (r > 0) { | |
2141 | const char *name; | |
4bbc06cc | 2142 | uint16_t type = 0; |
105e1512 | 2143 | |
1c02e7ba | 2144 | name = dns_resource_key_name(t->key); |
105e1512 | 2145 | |
4bbc06cc LP |
2146 | /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this |
2147 | * could also be used as indication that we are not at a zone apex, but in real world setups there are | |
2148 | * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even | |
2149 | * though they have further children. If this was a DS request, then it's signed when the parent zone | |
2150 | * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR, | |
2151 | * to see if that is signed. */ | |
105e1512 | 2152 | |
4bbc06cc | 2153 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2154 | r = dns_name_parent(&name); |
4bbc06cc LP |
2155 | if (r > 0) { |
2156 | type = DNS_TYPE_SOA; | |
2157 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty DS response).", | |
1c02e7ba | 2158 | t->id, dns_resource_key_name(t->key)); |
4bbc06cc | 2159 | } else |
105e1512 | 2160 | name = NULL; |
4bbc06cc LP |
2161 | |
2162 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) { | |
2163 | ||
2164 | type = DNS_TYPE_DS; | |
2165 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS response).", | |
2166 | t->id, dns_resource_key_name(t->key)); | |
2167 | ||
2168 | } else { | |
2169 | type = DNS_TYPE_SOA; | |
1c02e7ba ZJS |
2170 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", |
2171 | t->id, dns_resource_key_name(t->key)); | |
4bbc06cc | 2172 | } |
105e1512 LP |
2173 | |
2174 | if (name) { | |
2175 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2176 | ||
4bbc06cc | 2177 | soa = dns_resource_key_new(t->key->class, type, name); |
105e1512 LP |
2178 | if (!soa) |
2179 | return -ENOMEM; | |
2180 | ||
2181 | r = dns_transaction_request_dnssec_rr(t, soa); | |
2182 | if (r < 0) | |
2183 | return r; | |
2184 | } | |
2185 | } | |
2186 | ||
2187 | return dns_transaction_dnssec_is_live(t); | |
547973de LP |
2188 | } |
2189 | ||
2190 | void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { | |
547973de | 2191 | assert(t); |
547973de LP |
2192 | assert(source); |
2193 | ||
942eb2e7 LP |
2194 | /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING, |
2195 | we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If | |
2196 | the state is VALIDATING however, we should check if we are complete now. */ | |
105e1512 | 2197 | |
942eb2e7 LP |
2198 | if (t->state == DNS_TRANSACTION_VALIDATING) |
2199 | dns_transaction_process_dnssec(t); | |
547973de LP |
2200 | } |
2201 | ||
105e1512 LP |
2202 | static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { |
2203 | DnsResourceRecord *rr; | |
2204 | int ifindex, r; | |
2205 | ||
2206 | assert(t); | |
2207 | ||
2208 | /* Add all DNSKEY RRs from the answer that are validated by DS | |
2209 | * RRs from the list of validated keys to the list of | |
2210 | * validated keys. */ | |
2211 | ||
2212 | DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { | |
2213 | ||
96bb7673 | 2214 | r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); |
105e1512 LP |
2215 | if (r < 0) |
2216 | return r; | |
2217 | if (r == 0) | |
2218 | continue; | |
2219 | ||
2220 | /* If so, the DNSKEY is validated too. */ | |
2221 | r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); | |
2222 | if (r < 0) | |
2223 | return r; | |
2224 | } | |
2225 | ||
2226 | return 0; | |
2227 | } | |
2228 | ||
2229 | static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { | |
56352fe9 LP |
2230 | int r; |
2231 | ||
2232 | assert(t); | |
2233 | assert(rr); | |
2234 | ||
105e1512 LP |
2235 | /* Checks if the RR we are looking for must be signed with an |
2236 | * RRSIG. This is used for positive responses. */ | |
24a5b982 | 2237 | |
b652d4a2 | 2238 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2239 | return false; |
56352fe9 | 2240 | |
105e1512 LP |
2241 | if (dns_type_is_pseudo(rr->key->type)) |
2242 | return -EINVAL; | |
56352fe9 | 2243 | |
1c02e7ba | 2244 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2245 | if (r < 0) |
2246 | return r; | |
2247 | if (r > 0) | |
2248 | return false; | |
2249 | ||
105e1512 | 2250 | switch (rr->key->type) { |
56352fe9 | 2251 | |
105e1512 LP |
2252 | case DNS_TYPE_RRSIG: |
2253 | /* RRSIGs are the signatures themselves, they need no signing. */ | |
2254 | return false; | |
2255 | ||
2256 | case DNS_TYPE_SOA: | |
2257 | case DNS_TYPE_NS: { | |
2258 | DnsTransaction *dt; | |
2259 | Iterator i; | |
2260 | ||
b63fca62 | 2261 | /* For SOA or NS RRs we look for a matching DS transaction */ |
105e1512 LP |
2262 | |
2263 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2264 | ||
2265 | if (dt->key->class != rr->key->class) | |
2266 | continue; | |
2267 | if (dt->key->type != DNS_TYPE_DS) | |
2268 | continue; | |
2269 | ||
1c02e7ba | 2270 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2271 | if (r < 0) |
2272 | return r; | |
2273 | if (r == 0) | |
2274 | continue; | |
2275 | ||
2276 | /* We found a DS transactions for the SOA/NS | |
2277 | * RRs we are looking at. If it discovered signed DS | |
2278 | * RRs, then we need to be signed, too. */ | |
2279 | ||
097a2517 TA |
2280 | if (!dt->answer_authenticated) |
2281 | return false; | |
105e1512 | 2282 | |
097a2517 | 2283 | return dns_answer_match_key(dt->answer, dt->key, NULL); |
105e1512 LP |
2284 | } |
2285 | ||
2286 | /* We found nothing that proves this is safe to leave | |
2287 | * this unauthenticated, hence ask inist on | |
2288 | * authentication. */ | |
2289 | return true; | |
2290 | } | |
2291 | ||
b63fca62 | 2292 | case DNS_TYPE_DS: |
105e1512 LP |
2293 | case DNS_TYPE_CNAME: |
2294 | case DNS_TYPE_DNAME: { | |
2295 | const char *parent = NULL; | |
2296 | DnsTransaction *dt; | |
2297 | Iterator i; | |
2298 | ||
b63fca62 LP |
2299 | /* |
2300 | * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. | |
2301 | * | |
2302 | * DS RRs are signed if the parent is signed, hence also look at the parent SOA | |
2303 | */ | |
105e1512 LP |
2304 | |
2305 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2306 | ||
2307 | if (dt->key->class != rr->key->class) | |
2308 | continue; | |
2309 | if (dt->key->type != DNS_TYPE_SOA) | |
2310 | continue; | |
2311 | ||
2312 | if (!parent) { | |
1c02e7ba | 2313 | parent = dns_resource_key_name(rr->key); |
105e1512 LP |
2314 | r = dns_name_parent(&parent); |
2315 | if (r < 0) | |
2316 | return r; | |
2317 | if (r == 0) { | |
b63fca62 LP |
2318 | if (rr->key->type == DNS_TYPE_DS) |
2319 | return true; | |
2320 | ||
105e1512 LP |
2321 | /* A CNAME/DNAME without a parent? That's sooo weird. */ |
2322 | log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); | |
2323 | return -EBADMSG; | |
2324 | } | |
2325 | } | |
2326 | ||
1c02e7ba | 2327 | r = dns_name_equal(dns_resource_key_name(dt->key), parent); |
105e1512 LP |
2328 | if (r < 0) |
2329 | return r; | |
2330 | if (r == 0) | |
2331 | continue; | |
2332 | ||
2333 | return t->answer_authenticated; | |
2334 | } | |
2335 | ||
2336 | return true; | |
2337 | } | |
2338 | ||
2339 | default: { | |
2340 | DnsTransaction *dt; | |
2341 | Iterator i; | |
2342 | ||
b63fca62 | 2343 | /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ |
105e1512 LP |
2344 | |
2345 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2346 | ||
2347 | if (dt->key->class != rr->key->class) | |
2348 | continue; | |
2349 | if (dt->key->type != DNS_TYPE_SOA) | |
2350 | continue; | |
2351 | ||
1c02e7ba | 2352 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2353 | if (r < 0) |
2354 | return r; | |
2355 | if (r == 0) | |
2356 | continue; | |
2357 | ||
2358 | /* We found the transaction that was supposed to find | |
2359 | * the SOA RR for us. It was successful, but found no | |
2360 | * RR for us. This means we are not at a zone cut. In | |
2361 | * this case, we require authentication if the SOA | |
2362 | * lookup was authenticated too. */ | |
2363 | return t->answer_authenticated; | |
2364 | } | |
2365 | ||
2366 | return true; | |
2367 | }} | |
56352fe9 LP |
2368 | } |
2369 | ||
d33b6cf3 LP |
2370 | static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { |
2371 | DnsTransaction *dt; | |
2372 | const char *tld; | |
2373 | Iterator i; | |
2374 | int r; | |
2375 | ||
2376 | /* If DNSSEC downgrade mode is on, checks whether the | |
2377 | * specified RR is one level below a TLD we have proven not to | |
2378 | * exist. In such a case we assume that this is a private | |
2379 | * domain, and permit it. | |
2380 | * | |
2381 | * This detects cases like the Fritz!Box router networks. Each | |
2382 | * Fritz!Box router serves a private "fritz.box" zone, in the | |
2383 | * non-existing TLD "box". Requests for the "fritz.box" domain | |
2384 | * are served by the router itself, while requests for the | |
2385 | * "box" domain will result in NXDOMAIN. | |
2386 | * | |
2387 | * Note that this logic is unable to detect cases where a | |
2388 | * router serves a private DNS zone directly under | |
2389 | * non-existing TLD. In such a case we cannot detect whether | |
2390 | * the TLD is supposed to exist or not, as all requests we | |
2391 | * make for it will be answered by the router's zone, and not | |
2392 | * by the root zone. */ | |
2393 | ||
2394 | assert(t); | |
2395 | ||
2396 | if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) | |
2397 | return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ | |
2398 | ||
1c02e7ba | 2399 | tld = dns_resource_key_name(key); |
d33b6cf3 LP |
2400 | r = dns_name_parent(&tld); |
2401 | if (r < 0) | |
2402 | return r; | |
2403 | if (r == 0) | |
2404 | return false; /* Already the root domain */ | |
2405 | ||
2406 | if (!dns_name_is_single_label(tld)) | |
2407 | return false; | |
2408 | ||
2409 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2410 | ||
2411 | if (dt->key->class != key->class) | |
2412 | continue; | |
2413 | ||
1c02e7ba | 2414 | r = dns_name_equal(dns_resource_key_name(dt->key), tld); |
d33b6cf3 LP |
2415 | if (r < 0) |
2416 | return r; | |
2417 | if (r == 0) | |
2418 | continue; | |
2419 | ||
2420 | /* We found an auxiliary lookup we did for the TLD. If | |
2421 | * that returned with NXDOMAIN, we know the TLD didn't | |
2422 | * exist, and hence this might be a private zone. */ | |
2423 | ||
2424 | return dt->answer_rcode == DNS_RCODE_NXDOMAIN; | |
2425 | } | |
2426 | ||
2427 | return false; | |
2428 | } | |
2429 | ||
105e1512 | 2430 | static int dns_transaction_requires_nsec(DnsTransaction *t) { |
4bbc06cc | 2431 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
105e1512 LP |
2432 | DnsTransaction *dt; |
2433 | const char *name; | |
4bbc06cc | 2434 | uint16_t type = 0; |
105e1512 LP |
2435 | Iterator i; |
2436 | int r; | |
56352fe9 LP |
2437 | |
2438 | assert(t); | |
2439 | ||
105e1512 LP |
2440 | /* Checks if we need to insist on NSEC/NSEC3 RRs for proving |
2441 | * this negative reply */ | |
56352fe9 | 2442 | |
b652d4a2 | 2443 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2444 | return false; |
56352fe9 | 2445 | |
105e1512 LP |
2446 | if (dns_type_is_pseudo(t->key->type)) |
2447 | return -EINVAL; | |
2448 | ||
1c02e7ba | 2449 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
2450 | if (r < 0) |
2451 | return r; | |
2452 | if (r > 0) | |
2453 | return false; | |
2454 | ||
d33b6cf3 LP |
2455 | r = dns_transaction_in_private_tld(t, t->key); |
2456 | if (r < 0) | |
2457 | return r; | |
2458 | if (r > 0) { | |
2459 | /* The lookup is from a TLD that is proven not to | |
2460 | * exist, and we are in downgrade mode, hence ignore | |
13e785f7 | 2461 | * that fact that we didn't get any NSEC RRs. */ |
d33b6cf3 | 2462 | |
202b76ae ZJS |
2463 | log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", |
2464 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
d33b6cf3 LP |
2465 | return false; |
2466 | } | |
2467 | ||
1c02e7ba | 2468 | name = dns_resource_key_name(t->key); |
105e1512 | 2469 | |
4bbc06cc | 2470 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2471 | |
4bbc06cc LP |
2472 | /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed, |
2473 | * hence check the parent SOA in this case. */ | |
105e1512 LP |
2474 | |
2475 | r = dns_name_parent(&name); | |
56352fe9 LP |
2476 | if (r < 0) |
2477 | return r; | |
2478 | if (r == 0) | |
105e1512 | 2479 | return true; |
4bbc06cc LP |
2480 | |
2481 | type = DNS_TYPE_SOA; | |
2482 | ||
2483 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) | |
2484 | /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */ | |
2485 | type = DNS_TYPE_DS; | |
2486 | else | |
2487 | /* For all other negative replies, check for the SOA lookup */ | |
2488 | type = DNS_TYPE_SOA; | |
105e1512 LP |
2489 | |
2490 | /* For all other RRs we check the SOA on the same level to see | |
2491 | * if it's signed. */ | |
2492 | ||
2493 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2494 | ||
2495 | if (dt->key->class != t->key->class) | |
2496 | continue; | |
4bbc06cc | 2497 | if (dt->key->type != type) |
56352fe9 LP |
2498 | continue; |
2499 | ||
1c02e7ba | 2500 | r = dns_name_equal(dns_resource_key_name(dt->key), name); |
56352fe9 LP |
2501 | if (r < 0) |
2502 | return r; | |
105e1512 LP |
2503 | if (r == 0) |
2504 | continue; | |
2505 | ||
2506 | return dt->answer_authenticated; | |
56352fe9 LP |
2507 | } |
2508 | ||
105e1512 LP |
2509 | /* If in doubt, require NSEC/NSEC3 */ |
2510 | return true; | |
56352fe9 LP |
2511 | } |
2512 | ||
94aa7071 LP |
2513 | static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { |
2514 | DnsResourceRecord *rrsig; | |
2515 | bool found = false; | |
2516 | int r; | |
2517 | ||
2518 | /* Checks whether any of the DNSKEYs used for the RRSIGs for | |
2519 | * the specified RRset is authenticated (i.e. has a matching | |
2520 | * DS RR). */ | |
2521 | ||
1c02e7ba | 2522 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2523 | if (r < 0) |
2524 | return r; | |
2525 | if (r > 0) | |
2526 | return false; | |
2527 | ||
94aa7071 LP |
2528 | DNS_ANSWER_FOREACH(rrsig, t->answer) { |
2529 | DnsTransaction *dt; | |
2530 | Iterator i; | |
2531 | ||
2532 | r = dnssec_key_match_rrsig(rr->key, rrsig); | |
2533 | if (r < 0) | |
2534 | return r; | |
2535 | if (r == 0) | |
2536 | continue; | |
2537 | ||
2538 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2539 | ||
2540 | if (dt->key->class != rr->key->class) | |
2541 | continue; | |
2542 | ||
2543 | if (dt->key->type == DNS_TYPE_DNSKEY) { | |
2544 | ||
1c02e7ba | 2545 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2546 | if (r < 0) |
2547 | return r; | |
2548 | if (r == 0) | |
2549 | continue; | |
2550 | ||
2551 | /* OK, we found an auxiliary DNSKEY | |
2552 | * lookup. If that lookup is | |
2553 | * authenticated, report this. */ | |
2554 | ||
2555 | if (dt->answer_authenticated) | |
2556 | return true; | |
2557 | ||
2558 | found = true; | |
2559 | ||
2560 | } else if (dt->key->type == DNS_TYPE_DS) { | |
2561 | ||
1c02e7ba | 2562 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2563 | if (r < 0) |
2564 | return r; | |
2565 | if (r == 0) | |
2566 | continue; | |
2567 | ||
2568 | /* OK, we found an auxiliary DS | |
2569 | * lookup. If that lookup is | |
2570 | * authenticated and non-zero, we | |
2571 | * won! */ | |
2572 | ||
2573 | if (!dt->answer_authenticated) | |
2574 | return false; | |
2575 | ||
2576 | return dns_answer_match_key(dt->answer, dt->key, NULL); | |
2577 | } | |
2578 | } | |
2579 | } | |
2580 | ||
2581 | return found ? false : -ENXIO; | |
2582 | } | |
2583 | ||
b652d4a2 LP |
2584 | static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { |
2585 | assert(t); | |
2586 | assert(rr); | |
2587 | ||
2588 | /* We know that the root domain is signed, hence if it appears | |
2589 | * not to be signed, there's a problem with the DNS server */ | |
2590 | ||
2591 | return rr->key->class == DNS_CLASS_IN && | |
1c02e7ba | 2592 | dns_name_is_root(dns_resource_key_name(rr->key)); |
b652d4a2 LP |
2593 | } |
2594 | ||
0f87f3e8 LP |
2595 | static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { |
2596 | DnsResourceRecord *rr; | |
2597 | int r; | |
2598 | ||
2599 | assert(t); | |
2600 | ||
2601 | /* Maybe warn the user that we encountered a revoked DNSKEY | |
2602 | * for a key from our trust anchor. Note that we don't care | |
2603 | * whether the DNSKEY can be authenticated or not. It's | |
2604 | * sufficient if it is self-signed. */ | |
2605 | ||
2606 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
d424da2a | 2607 | r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); |
0f87f3e8 LP |
2608 | if (r < 0) |
2609 | return r; | |
2610 | } | |
2611 | ||
2612 | return 0; | |
2613 | } | |
2614 | ||
c9c72065 LP |
2615 | static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { |
2616 | bool changed; | |
2617 | int r; | |
2618 | ||
2619 | assert(t); | |
2620 | ||
2621 | /* Removes all DNSKEY/DS objects from t->validated_keys that | |
2622 | * our trust anchors database considers revoked. */ | |
2623 | ||
2624 | do { | |
2625 | DnsResourceRecord *rr; | |
2626 | ||
2627 | changed = false; | |
2628 | ||
2629 | DNS_ANSWER_FOREACH(rr, t->validated_keys) { | |
2630 | r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); | |
2631 | if (r < 0) | |
2632 | return r; | |
2633 | if (r > 0) { | |
2634 | r = dns_answer_remove_by_rr(&t->validated_keys, rr); | |
2635 | if (r < 0) | |
2636 | return r; | |
2637 | ||
2638 | assert(r > 0); | |
2639 | changed = true; | |
2640 | break; | |
2641 | } | |
2642 | } | |
2643 | } while (changed); | |
2644 | ||
2645 | return 0; | |
2646 | } | |
2647 | ||
942eb2e7 LP |
2648 | static int dns_transaction_copy_validated(DnsTransaction *t) { |
2649 | DnsTransaction *dt; | |
2650 | Iterator i; | |
2651 | int r; | |
2652 | ||
2653 | assert(t); | |
2654 | ||
2655 | /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */ | |
2656 | ||
2657 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2658 | ||
2659 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
2660 | continue; | |
2661 | ||
2662 | if (!dt->answer_authenticated) | |
2663 | continue; | |
2664 | ||
2665 | r = dns_answer_extend(&t->validated_keys, dt->answer); | |
2666 | if (r < 0) | |
2667 | return r; | |
2668 | } | |
2669 | ||
2670 | return 0; | |
2671 | } | |
2672 | ||
c690b20a ZJS |
2673 | typedef enum { |
2674 | DNSSEC_PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ | |
2675 | DNSSEC_PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ | |
2676 | DNSSEC_PHASE_ALL, /* Phase #3, validate everything else */ | |
2677 | } Phase; | |
2678 | ||
2679 | static int dnssec_validate_records( | |
2680 | DnsTransaction *t, | |
2681 | Phase phase, | |
2682 | bool *have_nsec, | |
2683 | DnsAnswer **validated) { | |
2684 | ||
547973de | 2685 | DnsResourceRecord *rr; |
56352fe9 | 2686 | int r; |
547973de | 2687 | |
c690b20a | 2688 | /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */ |
547973de | 2689 | |
c690b20a ZJS |
2690 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2691 | DnsResourceRecord *rrsig = NULL; | |
2692 | DnssecResult result; | |
547973de | 2693 | |
c690b20a ZJS |
2694 | switch (rr->key->type) { |
2695 | case DNS_TYPE_RRSIG: | |
2696 | continue; | |
547973de | 2697 | |
c690b20a ZJS |
2698 | case DNS_TYPE_DNSKEY: |
2699 | /* We validate DNSKEYs only in the DNSKEY and ALL phases */ | |
2700 | if (phase == DNSSEC_PHASE_NSEC) | |
2701 | continue; | |
2702 | break; | |
547973de | 2703 | |
c690b20a ZJS |
2704 | case DNS_TYPE_NSEC: |
2705 | case DNS_TYPE_NSEC3: | |
2706 | *have_nsec = true; | |
547973de | 2707 | |
c690b20a ZJS |
2708 | /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ |
2709 | if (phase == DNSSEC_PHASE_DNSKEY) | |
2710 | continue; | |
2711 | break; | |
105e1512 | 2712 | |
c690b20a ZJS |
2713 | default: |
2714 | /* We validate all other RRs only in the ALL phases */ | |
2715 | if (phase != DNSSEC_PHASE_ALL) | |
2716 | continue; | |
2717 | } | |
b652d4a2 | 2718 | |
c690b20a ZJS |
2719 | r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); |
2720 | if (r < 0) | |
2721 | return r; | |
547973de | 2722 | |
c690b20a | 2723 | log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); |
0f87f3e8 | 2724 | |
c690b20a | 2725 | if (result == DNSSEC_VALIDATED) { |
942eb2e7 | 2726 | |
c690b20a ZJS |
2727 | if (rr->key->type == DNS_TYPE_DNSKEY) { |
2728 | /* If we just validated a DNSKEY RRset, then let's add these keys to | |
2729 | * the set of validated keys for this transaction. */ | |
547973de | 2730 | |
c690b20a ZJS |
2731 | r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); |
2732 | if (r < 0) | |
2733 | return r; | |
c9c72065 | 2734 | |
c690b20a ZJS |
2735 | /* Some of the DNSKEYs we just added might already have been revoked, |
2736 | * remove them again in that case. */ | |
2737 | r = dns_transaction_invalidate_revoked_keys(t); | |
2738 | if (r < 0) | |
2739 | return r; | |
2740 | } | |
547973de | 2741 | |
c690b20a ZJS |
2742 | /* Add the validated RRset to the new list of validated |
2743 | * RRsets, and remove it from the unvalidated RRsets. | |
2744 | * We mark the RRset as authenticated and cacheable. */ | |
2745 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); | |
2746 | if (r < 0) | |
2747 | return r; | |
547973de | 2748 | |
c690b20a | 2749 | manager_dnssec_verdict(t->scope->manager, DNSSEC_SECURE, rr->key); |
0c7bff0a | 2750 | |
c690b20a ZJS |
2751 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
2752 | return 1; | |
2753 | } | |
547973de | 2754 | |
c690b20a ZJS |
2755 | /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as |
2756 | * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, | |
2757 | * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ | |
2758 | if (phase != DNSSEC_PHASE_ALL) | |
2759 | continue; | |
0c7bff0a | 2760 | |
c690b20a ZJS |
2761 | if (result == DNSSEC_VALIDATED_WILDCARD) { |
2762 | bool authenticated = false; | |
2763 | const char *source; | |
0c7bff0a | 2764 | |
c690b20a | 2765 | /* This RRset validated, but as a wildcard. This means we need |
13e785f7 | 2766 | * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */ |
0c7bff0a | 2767 | |
c690b20a ZJS |
2768 | /* First step, determine the source of synthesis */ |
2769 | r = dns_resource_record_source(rrsig, &source); | |
2770 | if (r < 0) | |
2771 | return r; | |
0c7bff0a | 2772 | |
c690b20a | 2773 | r = dnssec_test_positive_wildcard(*validated, |
1c02e7ba | 2774 | dns_resource_key_name(rr->key), |
c690b20a ZJS |
2775 | source, |
2776 | rrsig->rrsig.signer, | |
2777 | &authenticated); | |
0c7bff0a | 2778 | |
c690b20a ZJS |
2779 | /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ |
2780 | if (r == 0) | |
2781 | result = DNSSEC_INVALID; | |
2782 | else { | |
2783 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, | |
2784 | authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); | |
2785 | if (r < 0) | |
2786 | return r; | |
2787 | ||
2788 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, rr->key); | |
2789 | ||
2790 | /* Exit the loop, we dropped something from the answer, start from the beginning */ | |
2791 | return 1; | |
0c7bff0a | 2792 | } |
c690b20a | 2793 | } |
0c7bff0a | 2794 | |
c690b20a ZJS |
2795 | if (result == DNSSEC_NO_SIGNATURE) { |
2796 | r = dns_transaction_requires_rrsig(t, rr); | |
547973de LP |
2797 | if (r < 0) |
2798 | return r; | |
c690b20a ZJS |
2799 | if (r == 0) { |
2800 | /* Data does not require signing. In that case, just copy it over, | |
13e785f7 | 2801 | * but remember that this is by no means authenticated. */ |
c690b20a ZJS |
2802 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
2803 | if (r < 0) | |
2804 | return r; | |
2805 | ||
2806 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); | |
2807 | return 1; | |
2808 | } | |
547973de | 2809 | |
c690b20a ZJS |
2810 | r = dns_transaction_known_signed(t, rr); |
2811 | if (r < 0) | |
2812 | return r; | |
2813 | if (r > 0) { | |
2814 | /* This is an RR we know has to be signed. If it isn't this means | |
2815 | * the server is not attaching RRSIGs, hence complain. */ | |
547973de | 2816 | |
c690b20a | 2817 | dns_server_packet_rrsig_missing(t->server, t->current_feature_level); |
547973de | 2818 | |
c690b20a | 2819 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
547973de | 2820 | |
c690b20a | 2821 | /* Downgrading is OK? If so, just consider the information unsigned */ |
c9c72065 | 2822 | |
c690b20a | 2823 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
c9c72065 LP |
2824 | if (r < 0) |
2825 | return r; | |
547973de | 2826 | |
c690b20a ZJS |
2827 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2828 | return 1; | |
2829 | } | |
a150ff5e | 2830 | |
c690b20a ZJS |
2831 | /* Otherwise, fail */ |
2832 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
2833 | return 0; | |
f3cf586d | 2834 | } |
547973de | 2835 | |
c690b20a ZJS |
2836 | r = dns_transaction_in_private_tld(t, rr->key); |
2837 | if (r < 0) | |
2838 | return r; | |
2839 | if (r > 0) { | |
202b76ae | 2840 | char s[DNS_RESOURCE_KEY_STRING_MAX]; |
b652d4a2 | 2841 | |
c690b20a ZJS |
2842 | /* The data is from a TLD that is proven not to exist, and we are in downgrade |
2843 | * mode, hence ignore the fact that this was not signed. */ | |
0c7bff0a | 2844 | |
202b76ae ZJS |
2845 | log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", |
2846 | dns_resource_key_to_string(rr->key, s, sizeof s)); | |
0c7bff0a | 2847 | |
c690b20a | 2848 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
0c7bff0a LP |
2849 | if (r < 0) |
2850 | return r; | |
0c7bff0a | 2851 | |
c690b20a ZJS |
2852 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2853 | return 1; | |
2854 | } | |
2855 | } | |
0c7bff0a | 2856 | |
c690b20a ZJS |
2857 | if (IN_SET(result, |
2858 | DNSSEC_MISSING_KEY, | |
2859 | DNSSEC_SIGNATURE_EXPIRED, | |
2860 | DNSSEC_UNSUPPORTED_ALGORITHM)) { | |
0c7bff0a | 2861 | |
c690b20a ZJS |
2862 | r = dns_transaction_dnskey_authenticated(t, rr); |
2863 | if (r < 0 && r != -ENXIO) | |
2864 | return r; | |
2865 | if (r == 0) { | |
2866 | /* The DNSKEY transaction was not authenticated, this means there's | |
2867 | * no DS for this, which means it's OK if no keys are found for this signature. */ | |
0c7bff0a | 2868 | |
c690b20a | 2869 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
f3cf586d LP |
2870 | if (r < 0) |
2871 | return r; | |
b652d4a2 | 2872 | |
c690b20a ZJS |
2873 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2874 | return 1; | |
2875 | } | |
2876 | } | |
b652d4a2 | 2877 | |
c690b20a ZJS |
2878 | r = dns_transaction_is_primary_response(t, rr); |
2879 | if (r < 0) | |
2880 | return r; | |
2881 | if (r > 0) { | |
2882 | /* Look for a matching DNAME for this CNAME */ | |
2883 | r = dns_answer_has_dname_for_cname(t->answer, rr); | |
2884 | if (r < 0) | |
2885 | return r; | |
2886 | if (r == 0) { | |
2887 | /* Also look among the stuff we already validated */ | |
2888 | r = dns_answer_has_dname_for_cname(*validated, rr); | |
f3cf586d LP |
2889 | if (r < 0) |
2890 | return r; | |
c690b20a | 2891 | } |
d33b6cf3 | 2892 | |
c690b20a ZJS |
2893 | if (r == 0) { |
2894 | if (IN_SET(result, | |
2895 | DNSSEC_INVALID, | |
2896 | DNSSEC_SIGNATURE_EXPIRED, | |
2897 | DNSSEC_NO_SIGNATURE)) | |
2898 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, rr->key); | |
2899 | else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ | |
2900 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, rr->key); | |
2901 | ||
2902 | /* This is a primary response to our question, and it failed validation. | |
2903 | * That's fatal. */ | |
2904 | t->answer_dnssec_result = result; | |
2905 | return 0; | |
2906 | } | |
d33b6cf3 | 2907 | |
c690b20a ZJS |
2908 | /* This is a primary response, but we do have a DNAME RR |
2909 | * in the RR that can replay this CNAME, hence rely on | |
2910 | * that, and we can remove the CNAME in favour of it. */ | |
2911 | } | |
d33b6cf3 | 2912 | |
c690b20a ZJS |
2913 | /* This is just some auxiliary data. Just remove the RRset and continue. */ |
2914 | r = dns_answer_remove_by_key(&t->answer, rr->key); | |
2915 | if (r < 0) | |
2916 | return r; | |
d33b6cf3 | 2917 | |
c690b20a ZJS |
2918 | /* We dropped something from the answer, start from the beginning. */ |
2919 | return 1; | |
2920 | } | |
f3cf586d | 2921 | |
c690b20a ZJS |
2922 | return 2; /* Finito. */ |
2923 | } | |
94aa7071 | 2924 | |
c690b20a ZJS |
2925 | int dns_transaction_validate_dnssec(DnsTransaction *t) { |
2926 | _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; | |
2927 | Phase phase; | |
2928 | DnsAnswerFlags flags; | |
2929 | int r; | |
202b76ae | 2930 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
94aa7071 | 2931 | |
c690b20a | 2932 | assert(t); |
94aa7071 | 2933 | |
c690b20a ZJS |
2934 | /* We have now collected all DS and DNSKEY RRs in |
2935 | * t->validated_keys, let's see which RRs we can now | |
2936 | * authenticate with that. */ | |
94aa7071 | 2937 | |
c690b20a ZJS |
2938 | if (t->scope->dnssec_mode == DNSSEC_NO) |
2939 | return 0; | |
a150ff5e | 2940 | |
c690b20a ZJS |
2941 | /* Already validated */ |
2942 | if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) | |
2943 | return 0; | |
105e1512 | 2944 | |
c690b20a ZJS |
2945 | /* Our own stuff needs no validation */ |
2946 | if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { | |
2947 | t->answer_dnssec_result = DNSSEC_VALIDATED; | |
2948 | t->answer_authenticated = true; | |
2949 | return 0; | |
2950 | } | |
a150ff5e | 2951 | |
c690b20a ZJS |
2952 | /* Cached stuff is not affected by validation. */ |
2953 | if (t->answer_source != DNS_TRANSACTION_NETWORK) | |
2954 | return 0; | |
f3cf586d | 2955 | |
c690b20a ZJS |
2956 | if (!dns_transaction_dnssec_supported_full(t)) { |
2957 | /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ | |
2958 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
d001e0a3 | 2959 | log_debug("Not validating response for %" PRIu16 ", used server feature level does not support DNSSEC.", t->id); |
c690b20a ZJS |
2960 | return 0; |
2961 | } | |
f3cf586d | 2962 | |
202b76ae ZJS |
2963 | log_debug("Validating response from transaction %" PRIu16 " (%s).", |
2964 | t->id, | |
2965 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
547973de | 2966 | |
c690b20a ZJS |
2967 | /* First, see if this response contains any revoked trust |
2968 | * anchors we care about */ | |
2969 | r = dns_transaction_check_revoked_trust_anchors(t); | |
2970 | if (r < 0) | |
2971 | return r; | |
43e6779a | 2972 | |
c690b20a ZJS |
2973 | /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */ |
2974 | r = dns_transaction_copy_validated(t); | |
2975 | if (r < 0) | |
2976 | return r; | |
43e6779a | 2977 | |
c690b20a ZJS |
2978 | /* Second, see if there are DNSKEYs we already know a |
2979 | * validated DS for. */ | |
2980 | r = dns_transaction_validate_dnskey_by_ds(t); | |
2981 | if (r < 0) | |
2982 | return r; | |
43e6779a | 2983 | |
c690b20a ZJS |
2984 | /* Fourth, remove all DNSKEY and DS RRs again that our trust |
2985 | * anchor says are revoked. After all we might have marked | |
2986 | * some keys revoked above, but they might still be lingering | |
2987 | * in our validated_keys list. */ | |
2988 | r = dns_transaction_invalidate_revoked_keys(t); | |
2989 | if (r < 0) | |
2990 | return r; | |
f3cf586d | 2991 | |
c690b20a ZJS |
2992 | phase = DNSSEC_PHASE_DNSKEY; |
2993 | for (;;) { | |
2994 | bool have_nsec = false; | |
f3cf586d | 2995 | |
c690b20a ZJS |
2996 | r = dnssec_validate_records(t, phase, &have_nsec, &validated); |
2997 | if (r <= 0) | |
2998 | return r; | |
547973de | 2999 | |
c690b20a ZJS |
3000 | /* Try again as long as we managed to achieve something */ |
3001 | if (r == 1) | |
547973de LP |
3002 | continue; |
3003 | ||
c690b20a | 3004 | if (phase == DNSSEC_PHASE_DNSKEY && have_nsec) { |
0c7bff0a | 3005 | /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ |
c690b20a | 3006 | phase = DNSSEC_PHASE_NSEC; |
0c7bff0a LP |
3007 | continue; |
3008 | } | |
3009 | ||
c690b20a ZJS |
3010 | if (phase != DNSSEC_PHASE_ALL) { |
3011 | /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. | |
3012 | * Note that in this third phase we start to remove RRs we couldn't validate. */ | |
3013 | phase = DNSSEC_PHASE_ALL; | |
56352fe9 | 3014 | continue; |
547973de LP |
3015 | } |
3016 | ||
56352fe9 | 3017 | /* We're done */ |
547973de LP |
3018 | break; |
3019 | } | |
3020 | ||
3021 | dns_answer_unref(t->answer); | |
3022 | t->answer = validated; | |
3023 | validated = NULL; | |
3024 | ||
72667f08 LP |
3025 | /* At this point the answer only contains validated |
3026 | * RRsets. Now, let's see if it actually answers the question | |
3027 | * we asked. If so, great! If it doesn't, then see if | |
3028 | * NSEC/NSEC3 can prove this. */ | |
105e1512 | 3029 | r = dns_transaction_has_positive_answer(t, &flags); |
72667f08 | 3030 | if (r > 0) { |
105e1512 LP |
3031 | /* Yes, it answers the question! */ |
3032 | ||
3033 | if (flags & DNS_ANSWER_AUTHENTICATED) { | |
3034 | /* The answer is fully authenticated, yay. */ | |
019036a4 | 3035 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
105e1512 LP |
3036 | t->answer_rcode = DNS_RCODE_SUCCESS; |
3037 | t->answer_authenticated = true; | |
3038 | } else { | |
3039 | /* The answer is not fully authenticated. */ | |
019036a4 | 3040 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
3041 | t->answer_authenticated = false; |
3042 | } | |
3043 | ||
72667f08 LP |
3044 | } else if (r == 0) { |
3045 | DnssecNsecResult nr; | |
ed29bfdc | 3046 | bool authenticated = false; |
72667f08 LP |
3047 | |
3048 | /* Bummer! Let's check NSEC/NSEC3 */ | |
0c7bff0a | 3049 | r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); |
72667f08 LP |
3050 | if (r < 0) |
3051 | return r; | |
3052 | ||
3053 | switch (nr) { | |
3054 | ||
3055 | case DNSSEC_NSEC_NXDOMAIN: | |
3056 | /* NSEC proves the domain doesn't exist. Very good. */ | |
202b76ae | 3057 | log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3058 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3059 | t->answer_rcode = DNS_RCODE_NXDOMAIN; |
ed29bfdc | 3060 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3061 | |
59c5b597 | 3062 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3063 | break; |
3064 | ||
3065 | case DNSSEC_NSEC_NODATA: | |
3066 | /* NSEC proves that there's no data here, very good. */ | |
202b76ae | 3067 | log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3068 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3069 | t->answer_rcode = DNS_RCODE_SUCCESS; |
ed29bfdc | 3070 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3071 | |
59c5b597 | 3072 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3073 | break; |
3074 | ||
105e1512 LP |
3075 | case DNSSEC_NSEC_OPTOUT: |
3076 | /* NSEC3 says the data might not be signed */ | |
202b76ae | 3077 | log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3078 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3079 | t->answer_authenticated = false; |
7aa8ce98 | 3080 | |
59c5b597 | 3081 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3082 | break; |
3083 | ||
72667f08 LP |
3084 | case DNSSEC_NSEC_NO_RR: |
3085 | /* No NSEC data? Bummer! */ | |
105e1512 LP |
3086 | |
3087 | r = dns_transaction_requires_nsec(t); | |
3088 | if (r < 0) | |
3089 | return r; | |
7aa8ce98 | 3090 | if (r > 0) { |
019036a4 | 3091 | t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; |
59c5b597 | 3092 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
7aa8ce98 | 3093 | } else { |
019036a4 | 3094 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3095 | t->answer_authenticated = false; |
59c5b597 | 3096 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3097 | } |
3098 | ||
3099 | break; | |
3100 | ||
3101 | case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: | |
3102 | /* We don't know the NSEC3 algorithm used? */ | |
019036a4 | 3103 | t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; |
59c5b597 | 3104 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, t->key); |
72667f08 LP |
3105 | break; |
3106 | ||
3107 | case DNSSEC_NSEC_FOUND: | |
146035b3 | 3108 | case DNSSEC_NSEC_CNAME: |
72667f08 | 3109 | /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ |
019036a4 | 3110 | t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; |
59c5b597 | 3111 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
72667f08 LP |
3112 | break; |
3113 | ||
3114 | default: | |
3115 | assert_not_reached("Unexpected NSEC result."); | |
3116 | } | |
3117 | } | |
3118 | ||
547973de LP |
3119 | return 1; |
3120 | } | |
3121 | ||
ec2c5e43 LP |
3122 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { |
3123 | [DNS_TRANSACTION_NULL] = "null", | |
3124 | [DNS_TRANSACTION_PENDING] = "pending", | |
547973de | 3125 | [DNS_TRANSACTION_VALIDATING] = "validating", |
3bbdc31d | 3126 | [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", |
ec2c5e43 LP |
3127 | [DNS_TRANSACTION_SUCCESS] = "success", |
3128 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
3129 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
3130 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
3131 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
7cc6ed7b | 3132 | [DNS_TRANSACTION_ERRNO] = "errno", |
ec2c5e43 | 3133 | [DNS_TRANSACTION_ABORTED] = "aborted", |
547973de | 3134 | [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", |
b2b796b8 | 3135 | [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", |
91adc4db | 3136 | [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", |
edbcc1fd | 3137 | [DNS_TRANSACTION_NETWORK_DOWN] = "network-down", |
0791110f | 3138 | [DNS_TRANSACTION_NOT_FOUND] = "not-found", |
ec2c5e43 LP |
3139 | }; |
3140 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); | |
c3bc53e6 LP |
3141 | |
3142 | static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { | |
3143 | [DNS_TRANSACTION_NETWORK] = "network", | |
3144 | [DNS_TRANSACTION_CACHE] = "cache", | |
3145 | [DNS_TRANSACTION_ZONE] = "zone", | |
0d2cd476 | 3146 | [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", |
c3bc53e6 LP |
3147 | }; |
3148 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); |