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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
ec2c5e43 | 2 | |
62cc1c55 | 3 | #include "sd-messages.h" |
beef6a5f | 4 | |
ec2c5e43 | 5 | #include "af-list.h" |
b5efdb8a | 6 | #include "alloc-util.h" |
f52e61da | 7 | #include "dns-domain.h" |
7cc6ed7b | 8 | #include "errno-list.h" |
3ffd4af2 LP |
9 | #include "fd-util.h" |
10 | #include "random-util.h" | |
7778dfff | 11 | #include "resolved-dns-cache.h" |
3ffd4af2 LP |
12 | #include "resolved-dns-transaction.h" |
13 | #include "resolved-llmnr.h" | |
8b43440b | 14 | #include "string-table.h" |
ec2c5e43 | 15 | |
5d67a7ae IT |
16 | #if HAVE_GNUTLS |
17 | #include <gnutls/socket.h> | |
18 | #endif | |
19 | ||
b214dc0f | 20 | #define TRANSACTIONS_MAX 4096 |
dc349f5f | 21 | #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC) |
b214dc0f | 22 | |
dbc4661a MCO |
23 | /* After how much time to repeat classic DNS requests */ |
24 | #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX) | |
25 | ||
c61d2b44 LP |
26 | static void dns_transaction_reset_answer(DnsTransaction *t) { |
27 | assert(t); | |
28 | ||
29 | t->received = dns_packet_unref(t->received); | |
30 | t->answer = dns_answer_unref(t->answer); | |
31 | t->answer_rcode = 0; | |
32 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; | |
33 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; | |
34 | t->answer_authenticated = false; | |
d3760be0 | 35 | t->answer_nsec_ttl = (uint32_t) -1; |
7cc6ed7b | 36 | t->answer_errno = 0; |
c61d2b44 LP |
37 | } |
38 | ||
c5b4f861 LP |
39 | static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { |
40 | DnsTransaction *z; | |
41 | ||
42 | assert(t); | |
43 | ||
44 | while ((z = set_steal_first(t->dnssec_transactions))) { | |
45 | set_remove(z->notify_transactions, t); | |
35aa04e9 | 46 | set_remove(z->notify_transactions_done, t); |
c5b4f861 LP |
47 | dns_transaction_gc(z); |
48 | } | |
49 | } | |
50 | ||
f32f0e57 LP |
51 | static void dns_transaction_close_connection(DnsTransaction *t) { |
52 | assert(t); | |
53 | ||
b30bf55d LP |
54 | if (t->stream) { |
55 | /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ | |
98767d75 IT |
56 | LIST_REMOVE(transactions_by_stream, t->stream->transactions, t); |
57 | ||
58 | /* Remove packet in case it's still in the queue */ | |
59 | dns_packet_unref(ordered_set_remove(t->stream->write_queue, t->sent)); | |
60 | ||
b30bf55d LP |
61 | t->stream = dns_stream_unref(t->stream); |
62 | } | |
63 | ||
f32f0e57 LP |
64 | t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); |
65 | t->dns_udp_fd = safe_close(t->dns_udp_fd); | |
66 | } | |
67 | ||
f535705a | 68 | static void dns_transaction_stop_timeout(DnsTransaction *t) { |
97cc656c LP |
69 | assert(t); |
70 | ||
71 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
97cc656c LP |
72 | } |
73 | ||
ec2c5e43 | 74 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { |
801ad6a6 | 75 | DnsQueryCandidate *c; |
ec2c5e43 | 76 | DnsZoneItem *i; |
547973de | 77 | DnsTransaction *z; |
ec2c5e43 LP |
78 | |
79 | if (!t) | |
80 | return NULL; | |
81 | ||
51e399bc LP |
82 | log_debug("Freeing transaction %" PRIu16 ".", t->id); |
83 | ||
f32f0e57 | 84 | dns_transaction_close_connection(t); |
f535705a | 85 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 86 | |
ec2c5e43 | 87 | dns_packet_unref(t->sent); |
c61d2b44 | 88 | dns_transaction_reset_answer(t); |
ec2c5e43 | 89 | |
8300ba21 | 90 | dns_server_unref(t->server); |
ec2c5e43 LP |
91 | |
92 | if (t->scope) { | |
f9ebb22a LP |
93 | hashmap_remove_value(t->scope->transactions_by_key, t->key, t); |
94 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
ec2c5e43 LP |
95 | |
96 | if (t->id != 0) | |
97 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
98 | } | |
99 | ||
547973de | 100 | while ((c = set_steal_first(t->notify_query_candidates))) |
801ad6a6 | 101 | set_remove(c->transactions, t); |
547973de | 102 | set_free(t->notify_query_candidates); |
801ad6a6 | 103 | |
35aa04e9 LP |
104 | while ((c = set_steal_first(t->notify_query_candidates_done))) |
105 | set_remove(c->transactions, t); | |
106 | set_free(t->notify_query_candidates_done); | |
107 | ||
547973de | 108 | while ((i = set_steal_first(t->notify_zone_items))) |
ec2c5e43 | 109 | i->probe_transaction = NULL; |
547973de LP |
110 | set_free(t->notify_zone_items); |
111 | ||
35aa04e9 LP |
112 | while ((i = set_steal_first(t->notify_zone_items_done))) |
113 | i->probe_transaction = NULL; | |
114 | set_free(t->notify_zone_items_done); | |
115 | ||
547973de LP |
116 | while ((z = set_steal_first(t->notify_transactions))) |
117 | set_remove(z->dnssec_transactions, t); | |
118 | set_free(t->notify_transactions); | |
119 | ||
35aa04e9 LP |
120 | while ((z = set_steal_first(t->notify_transactions_done))) |
121 | set_remove(z->dnssec_transactions, t); | |
122 | set_free(t->notify_transactions_done); | |
123 | ||
c5b4f861 | 124 | dns_transaction_flush_dnssec_transactions(t); |
547973de LP |
125 | set_free(t->dnssec_transactions); |
126 | ||
127 | dns_answer_unref(t->validated_keys); | |
97cc656c | 128 | dns_resource_key_unref(t->key); |
97cc656c | 129 | |
6b430fdb | 130 | return mfree(t); |
ec2c5e43 LP |
131 | } |
132 | ||
133 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
134 | ||
51e399bc | 135 | bool dns_transaction_gc(DnsTransaction *t) { |
ec2c5e43 LP |
136 | assert(t); |
137 | ||
138 | if (t->block_gc > 0) | |
51e399bc | 139 | return true; |
ec2c5e43 | 140 | |
547973de | 141 | if (set_isempty(t->notify_query_candidates) && |
35aa04e9 | 142 | set_isempty(t->notify_query_candidates_done) && |
547973de | 143 | set_isempty(t->notify_zone_items) && |
35aa04e9 LP |
144 | set_isempty(t->notify_zone_items_done) && |
145 | set_isempty(t->notify_transactions) && | |
146 | set_isempty(t->notify_transactions_done)) { | |
ec2c5e43 | 147 | dns_transaction_free(t); |
51e399bc LP |
148 | return false; |
149 | } | |
150 | ||
151 | return true; | |
ec2c5e43 LP |
152 | } |
153 | ||
4dd15077 LP |
154 | static uint16_t pick_new_id(Manager *m) { |
155 | uint16_t new_id; | |
156 | ||
157 | /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of | |
158 | * transactions, and it's much lower than the space of IDs. */ | |
159 | ||
160 | assert_cc(TRANSACTIONS_MAX < 0xFFFF); | |
161 | ||
162 | do | |
163 | random_bytes(&new_id, sizeof(new_id)); | |
164 | while (new_id == 0 || | |
165 | hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id))); | |
166 | ||
167 | return new_id; | |
168 | } | |
169 | ||
f52e61da | 170 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { |
ec2c5e43 LP |
171 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; |
172 | int r; | |
173 | ||
174 | assert(ret); | |
175 | assert(s); | |
f52e61da | 176 | assert(key); |
ec2c5e43 | 177 | |
9eae2bf3 | 178 | /* Don't allow looking up invalid or pseudo RRs */ |
c463eb78 | 179 | if (!dns_type_is_valid_query(key->type)) |
9eae2bf3 | 180 | return -EINVAL; |
d0129ddb LP |
181 | if (dns_type_is_obsolete(key->type)) |
182 | return -EOPNOTSUPP; | |
9eae2bf3 LP |
183 | |
184 | /* We only support the IN class */ | |
4c701096 | 185 | if (!IN_SET(key->class, DNS_CLASS_IN, DNS_CLASS_ANY)) |
9eae2bf3 LP |
186 | return -EOPNOTSUPP; |
187 | ||
b214dc0f LP |
188 | if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX) |
189 | return -EBUSY; | |
190 | ||
d5099efc | 191 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
192 | if (r < 0) |
193 | return r; | |
194 | ||
f9ebb22a | 195 | r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); |
da0c630e LP |
196 | if (r < 0) |
197 | return r; | |
198 | ||
ec2c5e43 LP |
199 | t = new0(DnsTransaction, 1); |
200 | if (!t) | |
201 | return -ENOMEM; | |
202 | ||
4667e00a | 203 | t->dns_udp_fd = -1; |
c3bc53e6 | 204 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; |
019036a4 | 205 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
d3760be0 | 206 | t->answer_nsec_ttl = (uint32_t) -1; |
f52e61da | 207 | t->key = dns_resource_key_ref(key); |
274b8748 | 208 | t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
d001e0a3 | 209 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
ec2c5e43 | 210 | |
4dd15077 | 211 | t->id = pick_new_id(s->manager); |
ec2c5e43 LP |
212 | |
213 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
214 | if (r < 0) { | |
215 | t->id = 0; | |
216 | return r; | |
217 | } | |
218 | ||
f9ebb22a | 219 | r = hashmap_replace(s->transactions_by_key, t->key, t); |
da0c630e LP |
220 | if (r < 0) { |
221 | hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
222 | return r; | |
223 | } | |
224 | ||
f9ebb22a | 225 | LIST_PREPEND(transactions_by_scope, s->transactions, t); |
ec2c5e43 LP |
226 | t->scope = s; |
227 | ||
313cefa1 | 228 | s->manager->n_transactions_total++; |
a150ff5e | 229 | |
ec2c5e43 LP |
230 | if (ret) |
231 | *ret = t; | |
232 | ||
233 | t = NULL; | |
234 | ||
235 | return 0; | |
236 | } | |
237 | ||
4dd15077 LP |
238 | static void dns_transaction_shuffle_id(DnsTransaction *t) { |
239 | uint16_t new_id; | |
240 | assert(t); | |
241 | ||
242 | /* Pick a new ID for this transaction. */ | |
243 | ||
244 | new_id = pick_new_id(t->scope->manager); | |
245 | assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0); | |
246 | ||
247 | log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id); | |
248 | t->id = new_id; | |
249 | ||
250 | /* Make sure we generate a new packet with the new ID */ | |
251 | t->sent = dns_packet_unref(t->sent); | |
252 | } | |
253 | ||
ec2c5e43 | 254 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { |
2fb3034c | 255 | _cleanup_free_ char *pretty = NULL; |
202b76ae | 256 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 | 257 | DnsZoneItem *z; |
ec2c5e43 LP |
258 | |
259 | assert(t); | |
260 | assert(p); | |
261 | ||
262 | if (manager_our_packet(t->scope->manager, p) != 0) | |
263 | return; | |
264 | ||
164d025d | 265 | (void) in_addr_to_string(p->family, &p->sender, &pretty); |
2fb3034c | 266 | |
a5784c49 LP |
267 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", |
268 | t->id, | |
202b76ae | 269 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
270 | dns_protocol_to_string(t->scope->protocol), |
271 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 272 | af_to_name_short(t->scope->family), |
164d025d | 273 | strnull(pretty)); |
ec2c5e43 | 274 | |
a4076574 LP |
275 | /* RFC 4795, Section 4.1 says that the peer with the |
276 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
277 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
278 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
279 | return; |
280 | } | |
281 | ||
4d91eec4 | 282 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 283 | |
ec2c5e43 | 284 | t->block_gc++; |
35aa04e9 | 285 | |
547973de | 286 | while ((z = set_first(t->notify_zone_items))) { |
3ef64445 LP |
287 | /* First, make sure the zone item drops the reference |
288 | * to us */ | |
289 | dns_zone_item_probe_stop(z); | |
290 | ||
291 | /* Secondly, report this as conflict, so that we might | |
292 | * look for a different hostname */ | |
ec2c5e43 | 293 | dns_zone_item_conflict(z); |
3ef64445 | 294 | } |
ec2c5e43 LP |
295 | t->block_gc--; |
296 | ||
297 | dns_transaction_gc(t); | |
298 | } | |
299 | ||
300 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
801ad6a6 | 301 | DnsQueryCandidate *c; |
ec2c5e43 | 302 | DnsZoneItem *z; |
547973de | 303 | DnsTransaction *d; |
7cc6ed7b | 304 | const char *st; |
202b76ae | 305 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 LP |
306 | |
307 | assert(t); | |
547973de | 308 | assert(!DNS_TRANSACTION_IS_LIVE(state)); |
e56187ca | 309 | |
202b76ae ZJS |
310 | if (state == DNS_TRANSACTION_DNSSEC_FAILED) { |
311 | dns_resource_key_to_string(t->key, key_str, sizeof key_str); | |
312 | ||
f61dfddb | 313 | log_struct(LOG_NOTICE, |
2b044526 | 314 | "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR, |
202b76ae | 315 | LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str, dnssec_result_to_string(t->answer_dnssec_result)), |
f61dfddb | 316 | "DNS_TRANSACTION=%" PRIu16, t->id, |
202b76ae | 317 | "DNS_QUESTION=%s", key_str, |
f61dfddb | 318 | "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), |
1e02e182 | 319 | "DNS_SERVER=%s", dns_server_string(t->server), |
a1230ff9 | 320 | "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t->server->possible_feature_level)); |
202b76ae | 321 | } |
f61dfddb | 322 | |
ec2c5e43 LP |
323 | /* Note that this call might invalidate the query. Callers |
324 | * should hence not attempt to access the query or transaction | |
325 | * after calling this function. */ | |
326 | ||
7cc6ed7b LP |
327 | if (state == DNS_TRANSACTION_ERRNO) |
328 | st = errno_to_name(t->answer_errno); | |
329 | else | |
330 | st = dns_transaction_state_to_string(state); | |
331 | ||
a5784c49 LP |
332 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", |
333 | t->id, | |
202b76ae | 334 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
335 | dns_protocol_to_string(t->scope->protocol), |
336 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 337 | af_to_name_short(t->scope->family), |
7cc6ed7b | 338 | st, |
a5784c49 LP |
339 | t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), |
340 | t->answer_authenticated ? "authenticated" : "unsigned"); | |
ec2c5e43 LP |
341 | |
342 | t->state = state; | |
343 | ||
f32f0e57 | 344 | dns_transaction_close_connection(t); |
f535705a | 345 | dns_transaction_stop_timeout(t); |
ec2c5e43 LP |
346 | |
347 | /* Notify all queries that are interested, but make sure the | |
348 | * transaction isn't freed while we are still looking at it */ | |
349 | t->block_gc++; | |
f7014757 | 350 | |
35aa04e9 | 351 | SET_FOREACH_MOVE(c, t->notify_query_candidates_done, t->notify_query_candidates) |
547973de | 352 | dns_query_candidate_notify(c); |
35aa04e9 | 353 | SWAP_TWO(t->notify_query_candidates, t->notify_query_candidates_done); |
ec2c5e43 | 354 | |
35aa04e9 LP |
355 | SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items) |
356 | dns_zone_item_notify(z); | |
357 | SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done); | |
8d67e72c | 358 | if (t->probing && t->state == DNS_TRANSACTION_ATTEMPTS_MAX_REACHED) |
1a63fc54 | 359 | (void) dns_scope_announce(t->scope, false); |
f7014757 | 360 | |
35aa04e9 LP |
361 | SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions) |
362 | dns_transaction_notify(d, t); | |
363 | SWAP_TWO(t->notify_transactions, t->notify_transactions_done); | |
f7014757 LP |
364 | |
365 | t->block_gc--; | |
ec2c5e43 LP |
366 | dns_transaction_gc(t); |
367 | } | |
368 | ||
519ef046 LP |
369 | static int dns_transaction_pick_server(DnsTransaction *t) { |
370 | DnsServer *server; | |
371 | ||
372 | assert(t); | |
373 | assert(t->scope->protocol == DNS_PROTOCOL_DNS); | |
374 | ||
d001e0a3 LP |
375 | /* Pick a DNS server and a feature level for it. */ |
376 | ||
519ef046 LP |
377 | server = dns_scope_get_dns_server(t->scope); |
378 | if (!server) | |
379 | return -ESRCH; | |
380 | ||
d001e0a3 LP |
381 | /* If we changed the server invalidate the feature level clamping, as the new server might have completely |
382 | * different properties. */ | |
383 | if (server != t->server) | |
384 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; | |
385 | ||
274b8748 | 386 | t->current_feature_level = dns_server_possible_feature_level(server); |
519ef046 | 387 | |
d001e0a3 LP |
388 | /* Clamp the feature level if that is requested. */ |
389 | if (t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID && | |
390 | t->current_feature_level > t->clamp_feature_level) | |
391 | t->current_feature_level = t->clamp_feature_level; | |
392 | ||
393 | log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t->current_feature_level), t->id); | |
394 | ||
519ef046 LP |
395 | if (server == t->server) |
396 | return 0; | |
397 | ||
398 | dns_server_unref(t->server); | |
399 | t->server = dns_server_ref(server); | |
400 | ||
44db02d0 LP |
401 | t->n_picked_servers ++; |
402 | ||
d001e0a3 LP |
403 | log_debug("Using DNS server %s for transaction %u.", dns_server_string(t->server), t->id); |
404 | ||
519ef046 LP |
405 | return 1; |
406 | } | |
407 | ||
d001e0a3 | 408 | static void dns_transaction_retry(DnsTransaction *t, bool next_server) { |
8d10d620 LP |
409 | int r; |
410 | ||
411 | assert(t); | |
412 | ||
413 | log_debug("Retrying transaction %" PRIu16 ".", t->id); | |
414 | ||
415 | /* Before we try again, switch to a new server. */ | |
d001e0a3 LP |
416 | if (next_server) |
417 | dns_scope_next_dns_server(t->scope); | |
8d10d620 LP |
418 | |
419 | r = dns_transaction_go(t); | |
7cc6ed7b LP |
420 | if (r < 0) { |
421 | t->answer_errno = -r; | |
422 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
423 | } | |
8d10d620 LP |
424 | } |
425 | ||
c02cf2f4 | 426 | static int dns_transaction_maybe_restart(DnsTransaction *t) { |
5278bbfe LP |
427 | int r; |
428 | ||
c02cf2f4 LP |
429 | assert(t); |
430 | ||
5278bbfe LP |
431 | /* Returns > 0 if the transaction was restarted, 0 if not */ |
432 | ||
c02cf2f4 LP |
433 | if (!t->server) |
434 | return 0; | |
435 | ||
436 | if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) | |
437 | return 0; | |
438 | ||
439 | /* The server's current feature level is lower than when we sent the original query. We learnt something from | |
440 | the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to | |
441 | restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include | |
442 | OPT RR or DO bit. One of these cases is documented here, for example: | |
443 | https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ | |
444 | ||
4dd15077 LP |
445 | log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID."); |
446 | dns_transaction_shuffle_id(t); | |
5278bbfe LP |
447 | |
448 | r = dns_transaction_go(t); | |
449 | if (r < 0) | |
450 | return r; | |
451 | ||
452 | return 1; | |
c02cf2f4 LP |
453 | } |
454 | ||
98767d75 IT |
455 | static void on_transaction_stream_error(DnsTransaction *t, int error) { |
456 | assert(t); | |
ec2c5e43 | 457 | |
b30bf55d | 458 | dns_transaction_close_connection(t); |
ec2c5e43 | 459 | |
a1a3f73a | 460 | if (ERRNO_IS_DISCONNECT(error)) { |
0791110f LP |
461 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { |
462 | /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the | |
463 | * question on this scope. */ | |
464 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
daab72ea | 465 | return; |
0791110f LP |
466 | } |
467 | ||
d001e0a3 | 468 | dns_transaction_retry(t, true); |
daab72ea | 469 | return; |
ac720200 | 470 | } |
ec2c5e43 | 471 | if (error != 0) { |
7cc6ed7b LP |
472 | t->answer_errno = error; |
473 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 | 474 | } |
98767d75 IT |
475 | } |
476 | ||
477 | static int dns_transaction_on_stream_packet(DnsTransaction *t, DnsPacket *p) { | |
478 | assert(t); | |
479 | assert(p); | |
480 | ||
481 | dns_transaction_close_connection(t); | |
ec2c5e43 | 482 | |
a4076574 | 483 | if (dns_packet_validate_reply(p) <= 0) { |
a20b9592 | 484 | log_debug("Invalid TCP reply packet."); |
a4076574 LP |
485 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
486 | return 0; | |
487 | } | |
488 | ||
489 | dns_scope_check_conflicts(t->scope, p); | |
490 | ||
ec2c5e43 LP |
491 | t->block_gc++; |
492 | dns_transaction_process_reply(t, p); | |
493 | t->block_gc--; | |
494 | ||
519ef046 LP |
495 | /* If the response wasn't useful, then complete the transition |
496 | * now. After all, we are the worst feature set now with TCP | |
497 | * sockets, and there's really no point in retrying. */ | |
ec2c5e43 LP |
498 | if (t->state == DNS_TRANSACTION_PENDING) |
499 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
598f44bd LP |
500 | else |
501 | dns_transaction_gc(t); | |
ec2c5e43 LP |
502 | |
503 | return 0; | |
504 | } | |
505 | ||
5d67a7ae IT |
506 | static int on_stream_connection(DnsStream *s) { |
507 | #if HAVE_GNUTLS | |
508 | /* Store TLS Ticket for faster succesive TLS handshakes */ | |
509 | if (s->tls_session && s->server) { | |
510 | if (s->server->tls_session_data.data) | |
511 | gnutls_free(s->server->tls_session_data.data); | |
512 | ||
513 | gnutls_session_get_data2(s->tls_session, &s->server->tls_session_data); | |
514 | } | |
515 | #endif | |
516 | ||
517 | return 0; | |
518 | } | |
519 | ||
98767d75 IT |
520 | static int on_stream_complete(DnsStream *s, int error) { |
521 | DnsTransaction *t, *n; | |
522 | int r = 0; | |
523 | ||
524 | /* Do not let new transactions use this stream */ | |
525 | if (s->server && s->server->stream == s) | |
526 | s->server->stream = dns_stream_unref(s->server->stream); | |
527 | ||
528 | if (ERRNO_IS_DISCONNECT(error) && s->protocol != DNS_PROTOCOL_LLMNR) { | |
529 | usec_t usec; | |
530 | ||
531 | log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); | |
532 | ||
533 | if (s->transactions) { | |
534 | t = s->transactions; | |
535 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); | |
3da3cdd5 | 536 | dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level); |
98767d75 IT |
537 | } |
538 | } | |
539 | ||
540 | LIST_FOREACH_SAFE(transactions_by_stream, t, n, s->transactions) | |
541 | if (error != 0) | |
542 | on_transaction_stream_error(t, error); | |
543 | else if (DNS_PACKET_ID(s->read_packet) == t->id) | |
544 | /* As each transaction have a unique id the return code is only set once */ | |
545 | r = dns_transaction_on_stream_packet(t, s->read_packet); | |
546 | ||
547 | return r; | |
548 | } | |
549 | ||
550 | static int dns_stream_on_packet(DnsStream *s) { | |
551 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
552 | int r = 0; | |
553 | DnsTransaction *t; | |
554 | ||
555 | /* Take ownership of packet to be able to receive new packets */ | |
556 | p = TAKE_PTR(s->read_packet); | |
557 | s->n_read = 0; | |
558 | ||
559 | t = hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); | |
560 | ||
561 | /* Ignore incorrect transaction id as transaction can have been canceled */ | |
562 | if (t) | |
563 | r = dns_transaction_on_stream_packet(t, p); | |
564 | else { | |
565 | if (dns_packet_validate_reply(p) <= 0) { | |
566 | log_debug("Invalid TCP reply packet."); | |
567 | on_stream_complete(s, 0); | |
568 | } | |
569 | return 0; | |
570 | } | |
571 | ||
572 | return r; | |
573 | } | |
574 | ||
575 | static int dns_transaction_emit_tcp(DnsTransaction *t) { | |
ec2c5e43 | 576 | _cleanup_close_ int fd = -1; |
98767d75 | 577 | _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; |
91ccab1e | 578 | union sockaddr_union sa; |
ec2c5e43 | 579 | int r; |
5d67a7ae IT |
580 | #if HAVE_GNUTLS |
581 | gnutls_session_t gs; | |
582 | #endif | |
ec2c5e43 LP |
583 | |
584 | assert(t); | |
585 | ||
519ef046 | 586 | dns_transaction_close_connection(t); |
ec2c5e43 | 587 | |
106784eb | 588 | switch (t->scope->protocol) { |
519ef046 | 589 | |
106784eb | 590 | case DNS_PROTOCOL_DNS: |
519ef046 LP |
591 | r = dns_transaction_pick_server(t); |
592 | if (r < 0) | |
593 | return r; | |
594 | ||
92ec902a | 595 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
596 | return -EOPNOTSUPP; |
597 | ||
274b8748 | 598 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
599 | if (r < 0) |
600 | return r; | |
601 | ||
5d67a7ae | 602 | if (t->server->stream && (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level) == t->server->stream->encrypted)) |
98767d75 IT |
603 | s = dns_stream_ref(t->server->stream); |
604 | else | |
5d67a7ae | 605 | fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level) ? 853 : 53, &sa); |
98767d75 | 606 | |
106784eb | 607 | break; |
ec2c5e43 | 608 | |
106784eb | 609 | case DNS_PROTOCOL_LLMNR: |
a8f6397f | 610 | /* When we already received a reply to this (but it was truncated), send to its sender address */ |
ec2c5e43 | 611 | if (t->received) |
91ccab1e | 612 | fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port, &sa); |
ec2c5e43 LP |
613 | else { |
614 | union in_addr_union address; | |
a7f7d1bd | 615 | int family = AF_UNSPEC; |
ec2c5e43 LP |
616 | |
617 | /* Otherwise, try to talk to the owner of a | |
618 | * the IP address, in case this is a reverse | |
619 | * PTR lookup */ | |
f52e61da | 620 | |
1c02e7ba | 621 | r = dns_name_address(dns_resource_key_name(t->key), &family, &address); |
ec2c5e43 LP |
622 | if (r < 0) |
623 | return r; | |
624 | if (r == 0) | |
625 | return -EINVAL; | |
9e08a6e0 | 626 | if (family != t->scope->family) |
9318cdd3 | 627 | return -ESRCH; |
ec2c5e43 | 628 | |
91ccab1e | 629 | fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT, &sa); |
ec2c5e43 | 630 | } |
106784eb DM |
631 | |
632 | break; | |
633 | ||
634 | default: | |
ec2c5e43 | 635 | return -EAFNOSUPPORT; |
106784eb | 636 | } |
ec2c5e43 | 637 | |
98767d75 IT |
638 | if (!s) { |
639 | if (fd < 0) | |
640 | return fd; | |
ec2c5e43 | 641 | |
91ccab1e | 642 | r = dns_stream_new(t->scope->manager, &s, t->scope->protocol, fd, &sa); |
98767d75 IT |
643 | if (r < 0) |
644 | return r; | |
645 | ||
646 | fd = -1; | |
647 | ||
648 | if (t->server) { | |
649 | dns_stream_unref(t->server->stream); | |
650 | t->server->stream = dns_stream_ref(s); | |
651 | s->server = dns_server_ref(t->server); | |
652 | } | |
653 | ||
5d67a7ae IT |
654 | #if HAVE_GNUTLS |
655 | if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) { | |
656 | r = gnutls_init(&gs, GNUTLS_CLIENT | GNUTLS_ENABLE_FALSE_START | GNUTLS_NONBLOCK); | |
657 | if (r < 0) | |
658 | return r; | |
659 | ||
660 | /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */ | |
661 | r = gnutls_priority_set_direct(gs, "NORMAL:-VERS-ALL:+VERS-TLS1.2", NULL); | |
662 | if (r < 0) | |
663 | return r; | |
664 | ||
665 | r = gnutls_credentials_set(gs, GNUTLS_CRD_CERTIFICATE, t->server->tls_cert_cred); | |
666 | if (r < 0) | |
667 | return r; | |
668 | ||
669 | if (t->server && t->server->tls_session_data.size > 0) | |
670 | gnutls_session_set_data(gs, t->server->tls_session_data.data, t->server->tls_session_data.size); | |
671 | ||
672 | gnutls_handshake_set_timeout(gs, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT); | |
673 | ||
674 | r = dns_stream_connect_tls(s, gs); | |
675 | if (r < 0) | |
676 | return r; | |
677 | } | |
678 | #endif | |
679 | ||
680 | s->on_connection = on_stream_connection; | |
98767d75 IT |
681 | s->complete = on_stream_complete; |
682 | s->on_packet = dns_stream_on_packet; | |
683 | ||
684 | /* The interface index is difficult to determine if we are | |
685 | * connecting to the local host, hence fill this in right away | |
686 | * instead of determining it from the socket */ | |
687 | s->ifindex = dns_scope_ifindex(t->scope); | |
688 | } | |
689 | ||
690 | t->stream = TAKE_PTR(s); | |
691 | LIST_PREPEND(transactions_by_stream, t->stream->transactions, t); | |
ec2c5e43 LP |
692 | |
693 | r = dns_stream_write_packet(t->stream, t->sent); | |
694 | if (r < 0) { | |
98767d75 | 695 | dns_transaction_close_connection(t); |
ec2c5e43 LP |
696 | return r; |
697 | } | |
698 | ||
519ef046 LP |
699 | dns_transaction_reset_answer(t); |
700 | ||
cbe4216d LP |
701 | t->tried_stream = true; |
702 | ||
ec2c5e43 LP |
703 | return 0; |
704 | } | |
705 | ||
547973de | 706 | static void dns_transaction_cache_answer(DnsTransaction *t) { |
547973de LP |
707 | assert(t); |
708 | ||
709 | /* For mDNS we cache whenever we get the packet, rather than | |
710 | * in each transaction. */ | |
711 | if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) | |
712 | return; | |
713 | ||
ceeddf79 MP |
714 | /* Caching disabled? */ |
715 | if (!t->scope->manager->enable_cache) | |
716 | return; | |
717 | ||
547973de LP |
718 | /* We never cache if this packet is from the local host, under |
719 | * the assumption that a locally running DNS server would | |
720 | * cache this anyway, and probably knows better when to flush | |
721 | * the cache then we could. */ | |
722 | if (!DNS_PACKET_SHALL_CACHE(t->received)) | |
723 | return; | |
724 | ||
547973de LP |
725 | dns_cache_put(&t->scope->cache, |
726 | t->key, | |
727 | t->answer_rcode, | |
728 | t->answer, | |
547973de | 729 | t->answer_authenticated, |
d3760be0 | 730 | t->answer_nsec_ttl, |
547973de LP |
731 | 0, |
732 | t->received->family, | |
733 | &t->received->sender); | |
734 | } | |
735 | ||
105e1512 LP |
736 | static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { |
737 | DnsTransaction *dt; | |
738 | Iterator i; | |
739 | ||
740 | assert(t); | |
741 | ||
742 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
743 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
744 | return true; | |
745 | ||
746 | return false; | |
747 | } | |
748 | ||
942eb2e7 LP |
749 | static int dns_transaction_dnssec_ready(DnsTransaction *t) { |
750 | DnsTransaction *dt; | |
751 | Iterator i; | |
752 | ||
753 | assert(t); | |
754 | ||
755 | /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still | |
756 | * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */ | |
757 | ||
758 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
759 | ||
760 | switch (dt->state) { | |
761 | ||
762 | case DNS_TRANSACTION_NULL: | |
763 | case DNS_TRANSACTION_PENDING: | |
764 | case DNS_TRANSACTION_VALIDATING: | |
765 | /* Still ongoing */ | |
766 | return 0; | |
767 | ||
768 | case DNS_TRANSACTION_RCODE_FAILURE: | |
b3c6b00a | 769 | if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) { |
942eb2e7 LP |
770 | log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode)); |
771 | goto fail; | |
772 | } | |
773 | ||
b3c6b00a LP |
774 | /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers |
775 | * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS | |
776 | * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar | |
777 | * RRs to make unsigned proofs. */ | |
942eb2e7 LP |
778 | |
779 | case DNS_TRANSACTION_SUCCESS: | |
780 | /* All good. */ | |
781 | break; | |
782 | ||
783 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
784 | /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC | |
785 | * validationr result */ | |
786 | ||
787 | log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result)); | |
788 | t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */ | |
789 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
790 | return 0; | |
791 | ||
942eb2e7 LP |
792 | default: |
793 | log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state)); | |
794 | goto fail; | |
795 | } | |
796 | } | |
797 | ||
798 | /* All is ready, we can go and validate */ | |
799 | return 1; | |
800 | ||
801 | fail: | |
802 | t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; | |
803 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
804 | return 0; | |
805 | } | |
806 | ||
547973de LP |
807 | static void dns_transaction_process_dnssec(DnsTransaction *t) { |
808 | int r; | |
809 | ||
810 | assert(t); | |
811 | ||
812 | /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ | |
942eb2e7 | 813 | r = dns_transaction_dnssec_ready(t); |
7cc6ed7b LP |
814 | if (r < 0) |
815 | goto fail; | |
942eb2e7 | 816 | if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */ |
547973de LP |
817 | return; |
818 | ||
c02cf2f4 LP |
819 | /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better |
820 | * restart the lookup immediately. */ | |
821 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
822 | if (r < 0) |
823 | goto fail; | |
c02cf2f4 LP |
824 | if (r > 0) /* Transaction got restarted... */ |
825 | return; | |
826 | ||
547973de LP |
827 | /* All our auxiliary DNSSEC transactions are complete now. Try |
828 | * to validate our RRset now. */ | |
829 | r = dns_transaction_validate_dnssec(t); | |
fcfaff12 LP |
830 | if (r == -EBADMSG) { |
831 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
832 | return; | |
833 | } | |
7cc6ed7b LP |
834 | if (r < 0) |
835 | goto fail; | |
547973de | 836 | |
b652d4a2 LP |
837 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && |
838 | t->scope->dnssec_mode == DNSSEC_YES) { | |
e82b1132 LP |
839 | |
840 | /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe | |
841 | * that works. */ | |
842 | ||
843 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { | |
844 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
845 | dns_transaction_retry(t, true); | |
846 | return; | |
847 | } | |
848 | ||
849 | /* OK, let's give up, apparently all servers we tried didn't work. */ | |
b652d4a2 LP |
850 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
851 | return; | |
852 | } | |
853 | ||
019036a4 | 854 | if (!IN_SET(t->answer_dnssec_result, |
b652d4a2 LP |
855 | _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ |
856 | DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ | |
857 | DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ | |
858 | DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ | |
547973de LP |
859 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
860 | return; | |
861 | } | |
862 | ||
1e02e182 LP |
863 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER) |
864 | dns_server_warn_downgrade(t->server); | |
865 | ||
547973de LP |
866 | dns_transaction_cache_answer(t); |
867 | ||
868 | if (t->answer_rcode == DNS_RCODE_SUCCESS) | |
869 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
870 | else | |
3bbdc31d | 871 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
7cc6ed7b LP |
872 | |
873 | return; | |
874 | ||
875 | fail: | |
876 | t->answer_errno = -r; | |
877 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
547973de LP |
878 | } |
879 | ||
eac7cda2 LP |
880 | static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { |
881 | int r; | |
882 | ||
883 | assert(t); | |
884 | ||
885 | /* Checks whether the answer is positive, i.e. either a direct | |
886 | * answer to the question, or a CNAME/DNAME for it */ | |
887 | ||
888 | r = dns_answer_match_key(t->answer, t->key, flags); | |
889 | if (r != 0) | |
890 | return r; | |
891 | ||
892 | r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); | |
893 | if (r != 0) | |
894 | return r; | |
895 | ||
896 | return false; | |
897 | } | |
898 | ||
899 | static int dns_transaction_fix_rcode(DnsTransaction *t) { | |
900 | int r; | |
901 | ||
902 | assert(t); | |
903 | ||
904 | /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the | |
905 | * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a | |
906 | * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first | |
907 | * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when | |
908 | * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle | |
909 | * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a | |
910 | * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server | |
911 | * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an | |
912 | * incomplete CNAME/DNAME chain. | |
913 | * | |
914 | * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS, | |
915 | * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new | |
916 | * lookup. */ | |
917 | ||
918 | if (t->answer_rcode != DNS_RCODE_NXDOMAIN) | |
919 | return 0; | |
920 | ||
921 | r = dns_transaction_has_positive_answer(t, NULL); | |
922 | if (r <= 0) | |
923 | return r; | |
924 | ||
925 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
926 | return 0; | |
927 | } | |
928 | ||
ec2c5e43 | 929 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { |
9df3ba6c | 930 | usec_t ts; |
ec2c5e43 LP |
931 | int r; |
932 | ||
933 | assert(t); | |
934 | assert(p); | |
9df3ba6c TG |
935 | assert(t->scope); |
936 | assert(t->scope->manager); | |
ec2c5e43 | 937 | |
5a7e41a3 LP |
938 | if (t->state != DNS_TRANSACTION_PENDING) |
939 | return; | |
940 | ||
ec2c5e43 LP |
941 | /* Note that this call might invalidate the query. Callers |
942 | * should hence not attempt to access the query or transaction | |
943 | * after calling this function. */ | |
944 | ||
1fdeaeb7 | 945 | log_debug("Processing incoming packet on transaction %" PRIu16". (rcode=%s)", t->id, dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
b5efcf29 | 946 | |
106784eb | 947 | switch (t->scope->protocol) { |
b5efcf29 | 948 | |
106784eb | 949 | case DNS_PROTOCOL_LLMNR: |
97ebebbc | 950 | /* For LLMNR we will not accept any packets from other interfaces */ |
ec2c5e43 | 951 | |
97ebebbc | 952 | if (p->ifindex != dns_scope_ifindex(t->scope)) |
ec2c5e43 LP |
953 | return; |
954 | ||
955 | if (p->family != t->scope->family) | |
956 | return; | |
957 | ||
958 | /* Tentative packets are not full responses but still | |
959 | * useful for identifying uniqueness conflicts during | |
960 | * probing. */ | |
8b757a38 | 961 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
962 | dns_transaction_tentative(t, p); |
963 | return; | |
964 | } | |
106784eb DM |
965 | |
966 | break; | |
967 | ||
4e5bf5e1 | 968 | case DNS_PROTOCOL_MDNS: |
4e5bf5e1 | 969 | /* For mDNS we will not accept any packets from other interfaces */ |
97ebebbc LP |
970 | |
971 | if (p->ifindex != dns_scope_ifindex(t->scope)) | |
4e5bf5e1 DM |
972 | return; |
973 | ||
974 | if (p->family != t->scope->family) | |
975 | return; | |
976 | ||
977 | break; | |
978 | ||
106784eb | 979 | case DNS_PROTOCOL_DNS: |
8ad182a1 LP |
980 | /* Note that we do not need to verify the |
981 | * addresses/port numbers of incoming traffic, as we | |
982 | * invoked connect() on our UDP socket in which case | |
983 | * the kernel already does the needed verification for | |
984 | * us. */ | |
106784eb DM |
985 | break; |
986 | ||
987 | default: | |
9c56a6f3 | 988 | assert_not_reached("Invalid DNS protocol."); |
ec2c5e43 LP |
989 | } |
990 | ||
ec2c5e43 LP |
991 | if (t->received != p) { |
992 | dns_packet_unref(t->received); | |
993 | t->received = dns_packet_ref(p); | |
994 | } | |
995 | ||
c3bc53e6 LP |
996 | t->answer_source = DNS_TRANSACTION_NETWORK; |
997 | ||
ec2c5e43 LP |
998 | if (p->ipproto == IPPROTO_TCP) { |
999 | if (DNS_PACKET_TC(p)) { | |
1000 | /* Truncated via TCP? Somebody must be fucking with us */ | |
1001 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1002 | return; | |
1003 | } | |
1004 | ||
1005 | if (DNS_PACKET_ID(p) != t->id) { | |
1006 | /* Not the reply to our query? Somebody must be fucking with us */ | |
1007 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1008 | return; | |
1009 | } | |
1010 | } | |
1011 | ||
38a03f06 | 1012 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
9df3ba6c TG |
1013 | |
1014 | switch (t->scope->protocol) { | |
8af5b883 | 1015 | |
9df3ba6c TG |
1016 | case DNS_PROTOCOL_DNS: |
1017 | assert(t->server); | |
1018 | ||
4e0b8b17 TG |
1019 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { |
1020 | ||
8af5b883 | 1021 | /* Request failed, immediately try again with reduced features */ |
4e0b8b17 | 1022 | |
7d581a65 | 1023 | if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) { |
44db02d0 | 1024 | |
7d581a65 | 1025 | /* This was already at UDP feature level? If so, it doesn't make sense to downgrade |
44db02d0 LP |
1026 | * this transaction anymore, but let's see if it might make sense to send the request |
1027 | * to a different DNS server instead. If not let's process the response, and accept the | |
7d581a65 LP |
1028 | * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate |
1029 | * packet loss, but is not going to give us better rcodes should we actually have | |
1030 | * managed to get them already at UDP level. */ | |
1031 | ||
44db02d0 LP |
1032 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { |
1033 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
1034 | dns_transaction_retry(t, true); | |
1035 | return; | |
1036 | } | |
1037 | ||
1038 | /* Give up, accept the rcode */ | |
d001e0a3 LP |
1039 | log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
1040 | break; | |
1041 | } | |
1042 | ||
1043 | /* Reduce this feature level by one and try again. */ | |
5d67a7ae IT |
1044 | switch (t->current_feature_level) { |
1045 | case DNS_SERVER_FEATURE_LEVEL_TLS_DO: | |
1046 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN; | |
1047 | break; | |
1048 | case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN + 1: | |
1049 | /* Skip plain TLS when TLS is not supported */ | |
1050 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN - 1; | |
1051 | break; | |
1052 | default: | |
1053 | t->clamp_feature_level = t->current_feature_level - 1; | |
1054 | } | |
d001e0a3 LP |
1055 | |
1056 | log_debug("Server returned error %s, retrying transaction with reduced feature level %s.", | |
1057 | dns_rcode_to_string(DNS_PACKET_RCODE(p)), | |
1058 | dns_server_feature_level_to_string(t->clamp_feature_level)); | |
1059 | ||
1060 | dns_transaction_retry(t, false /* use the same server */); | |
4e0b8b17 | 1061 | return; |
eb08640a LP |
1062 | } |
1063 | ||
1064 | if (DNS_PACKET_RCODE(p) == DNS_RCODE_REFUSED) { | |
1065 | /* This server refused our request? If so, try again, use a different server */ | |
1066 | log_debug("Server returned REFUSED, switching servers, and retrying."); | |
1067 | dns_transaction_retry(t, true /* pick a new server */); | |
1068 | return; | |
1069 | } | |
1070 | ||
1071 | if (DNS_PACKET_TC(p)) | |
274b8748 | 1072 | dns_server_packet_truncated(t->server, t->current_feature_level); |
9df3ba6c TG |
1073 | |
1074 | break; | |
8af5b883 | 1075 | |
9df3ba6c TG |
1076 | case DNS_PROTOCOL_LLMNR: |
1077 | case DNS_PROTOCOL_MDNS: | |
1078 | dns_scope_packet_received(t->scope, ts - t->start_usec); | |
9df3ba6c | 1079 | break; |
8af5b883 | 1080 | |
9df3ba6c | 1081 | default: |
8af5b883 | 1082 | assert_not_reached("Invalid DNS protocol."); |
9df3ba6c TG |
1083 | } |
1084 | ||
ec2c5e43 | 1085 | if (DNS_PACKET_TC(p)) { |
547493c5 DM |
1086 | |
1087 | /* Truncated packets for mDNS are not allowed. Give up immediately. */ | |
1088 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) { | |
1089 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1090 | return; | |
1091 | } | |
1092 | ||
f757cd85 LP |
1093 | log_debug("Reply truncated, retrying via TCP."); |
1094 | ||
ec2c5e43 | 1095 | /* Response was truncated, let's try again with good old TCP */ |
98767d75 | 1096 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 LP |
1097 | if (r == -ESRCH) { |
1098 | /* No servers found? Damn! */ | |
1099 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1100 | return; | |
1101 | } | |
91adc4db LP |
1102 | if (r == -EOPNOTSUPP) { |
1103 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1104 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1105 | return; | |
1106 | } | |
ec2c5e43 | 1107 | if (r < 0) { |
8af5b883 | 1108 | /* On LLMNR, if we cannot connect to the host, |
ec2c5e43 | 1109 | * we immediately give up */ |
7cc6ed7b LP |
1110 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1111 | goto fail; | |
ec2c5e43 LP |
1112 | |
1113 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
d001e0a3 | 1114 | dns_transaction_retry(t, true); |
ec2c5e43 | 1115 | } |
2a6658ef LP |
1116 | |
1117 | return; | |
ec2c5e43 LP |
1118 | } |
1119 | ||
de54e62b | 1120 | /* After the superficial checks, actually parse the message. */ |
ec2c5e43 LP |
1121 | r = dns_packet_extract(p); |
1122 | if (r < 0) { | |
1123 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1124 | return; | |
1125 | } | |
1126 | ||
ed9717fc | 1127 | if (t->server) { |
d001e0a3 LP |
1128 | /* Report that we successfully received a valid packet with a good rcode after we initially got a bad |
1129 | * rcode and subsequently downgraded the protocol */ | |
1130 | ||
1131 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN) && | |
1132 | t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID) | |
1133 | dns_server_packet_rcode_downgrade(t->server, t->clamp_feature_level); | |
1134 | ||
1135 | /* Report that the OPT RR was missing */ | |
ed9717fc LP |
1136 | if (!p->opt) |
1137 | dns_server_packet_bad_opt(t->server, t->current_feature_level); | |
1138 | ||
d001e0a3 | 1139 | /* Report that we successfully received a packet */ |
dbc4661a | 1140 | dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, p->size); |
ed9717fc | 1141 | } |
de54e62b | 1142 | |
c02cf2f4 LP |
1143 | /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ |
1144 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
1145 | if (r < 0) |
1146 | goto fail; | |
c02cf2f4 LP |
1147 | if (r > 0) /* Transaction got restarted... */ |
1148 | return; | |
1149 | ||
8b419837 | 1150 | if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
b5efcf29 | 1151 | |
8b419837 DR |
1152 | /* When dealing with protocols other than mDNS only consider responses with |
1153 | * equivalent query section to the request. For mDNS this check doesn't make | |
1154 | * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT | |
1155 | * contain any questions in the Question Section". */ | |
1156 | if (t->scope->protocol != DNS_PROTOCOL_MDNS) { | |
1157 | r = dns_packet_is_reply_for(p, t->key); | |
1158 | if (r < 0) | |
1159 | goto fail; | |
1160 | if (r == 0) { | |
1161 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1162 | return; | |
1163 | } | |
547493c5 | 1164 | } |
29815b6c | 1165 | |
547493c5 DM |
1166 | /* Install the answer as answer to the transaction */ |
1167 | dns_answer_unref(t->answer); | |
1168 | t->answer = dns_answer_ref(p->answer); | |
1169 | t->answer_rcode = DNS_PACKET_RCODE(p); | |
919c2ae0 | 1170 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
105e1512 | 1171 | t->answer_authenticated = false; |
79e24931 | 1172 | |
eac7cda2 LP |
1173 | r = dns_transaction_fix_rcode(t); |
1174 | if (r < 0) | |
1175 | goto fail; | |
1176 | ||
51e399bc LP |
1177 | /* Block GC while starting requests for additional DNSSEC RRs */ |
1178 | t->block_gc++; | |
547973de | 1179 | r = dns_transaction_request_dnssec_keys(t); |
51e399bc LP |
1180 | t->block_gc--; |
1181 | ||
1182 | /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ | |
1183 | if (!dns_transaction_gc(t)) | |
1184 | return; | |
1185 | ||
1186 | /* Requesting additional keys might have resulted in | |
1187 | * this transaction to fail, since the auxiliary | |
1188 | * request failed for some reason. If so, we are not | |
1189 | * in pending state anymore, and we should exit | |
1190 | * quickly. */ | |
1191 | if (t->state != DNS_TRANSACTION_PENDING) | |
1192 | return; | |
7cc6ed7b LP |
1193 | if (r < 0) |
1194 | goto fail; | |
547973de LP |
1195 | if (r > 0) { |
1196 | /* There are DNSSEC transactions pending now. Update the state accordingly. */ | |
1197 | t->state = DNS_TRANSACTION_VALIDATING; | |
f535705a LP |
1198 | dns_transaction_close_connection(t); |
1199 | dns_transaction_stop_timeout(t); | |
547973de LP |
1200 | return; |
1201 | } | |
547493c5 | 1202 | } |
ec2c5e43 | 1203 | |
547973de | 1204 | dns_transaction_process_dnssec(t); |
7cc6ed7b LP |
1205 | return; |
1206 | ||
1207 | fail: | |
1208 | t->answer_errno = -r; | |
1209 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 LP |
1210 | } |
1211 | ||
c19ffd9f TG |
1212 | static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
1213 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1214 | DnsTransaction *t = userdata; | |
1215 | int r; | |
1216 | ||
1217 | assert(t); | |
1218 | assert(t->scope); | |
1219 | ||
1220 | r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); | |
7e1851e3 LP |
1221 | if (ERRNO_IS_DISCONNECT(-r)) { |
1222 | usec_t usec; | |
c19ffd9f | 1223 | |
7e1851e3 LP |
1224 | /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next |
1225 | * recvmsg(). Treat this like a lost packet. */ | |
1226 | ||
92ec902a | 1227 | log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); |
7e1851e3 | 1228 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
3da3cdd5 | 1229 | dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level); |
7e1851e3 | 1230 | |
d001e0a3 | 1231 | dns_transaction_retry(t, true); |
7e1851e3 LP |
1232 | return 0; |
1233 | } | |
1234 | if (r < 0) { | |
7cc6ed7b LP |
1235 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); |
1236 | t->answer_errno = -r; | |
7e1851e3 LP |
1237 | return 0; |
1238 | } | |
1239 | ||
1240 | r = dns_packet_validate_reply(p); | |
1241 | if (r < 0) { | |
1242 | log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); | |
1243 | return 0; | |
1244 | } | |
1245 | if (r == 0) { | |
e09f605e | 1246 | log_debug("Received inappropriate DNS packet as response, ignoring."); |
7e1851e3 LP |
1247 | return 0; |
1248 | } | |
1249 | ||
1250 | if (DNS_PACKET_ID(p) != t->id) { | |
e09f605e | 1251 | log_debug("Received packet with incorrect transaction ID, ignoring."); |
7e1851e3 LP |
1252 | return 0; |
1253 | } | |
c19ffd9f | 1254 | |
7e1851e3 | 1255 | dns_transaction_process_reply(t, p); |
c19ffd9f TG |
1256 | return 0; |
1257 | } | |
1258 | ||
49cce12d | 1259 | static int dns_transaction_emit_udp(DnsTransaction *t) { |
c19ffd9f TG |
1260 | int r; |
1261 | ||
1262 | assert(t); | |
c19ffd9f | 1263 | |
519ef046 | 1264 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { |
c19ffd9f | 1265 | |
519ef046 | 1266 | r = dns_transaction_pick_server(t); |
471d40d9 TG |
1267 | if (r < 0) |
1268 | return r; | |
c19ffd9f | 1269 | |
5d67a7ae | 1270 | if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP || DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) |
7d581a65 | 1271 | return -EAGAIN; /* Sorry, can't do UDP, try TCP! */ |
519ef046 | 1272 | |
92ec902a | 1273 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
1274 | return -EOPNOTSUPP; |
1275 | ||
519ef046 LP |
1276 | if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ |
1277 | int fd; | |
1278 | ||
1279 | dns_transaction_close_connection(t); | |
c19ffd9f | 1280 | |
519ef046 LP |
1281 | fd = dns_scope_socket_udp(t->scope, t->server, 53); |
1282 | if (fd < 0) | |
1283 | return fd; | |
1284 | ||
1285 | r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); | |
1286 | if (r < 0) { | |
1287 | safe_close(fd); | |
1288 | return r; | |
1289 | } | |
1290 | ||
aa4a9deb | 1291 | (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); |
519ef046 LP |
1292 | t->dns_udp_fd = fd; |
1293 | } | |
1294 | ||
274b8748 | 1295 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
1296 | if (r < 0) |
1297 | return r; | |
1298 | } else | |
1299 | dns_transaction_close_connection(t); | |
1300 | ||
1301 | r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); | |
471d40d9 TG |
1302 | if (r < 0) |
1303 | return r; | |
c19ffd9f | 1304 | |
519ef046 | 1305 | dns_transaction_reset_answer(t); |
be808ea0 | 1306 | |
471d40d9 | 1307 | return 0; |
c19ffd9f TG |
1308 | } |
1309 | ||
ec2c5e43 LP |
1310 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { |
1311 | DnsTransaction *t = userdata; | |
ec2c5e43 LP |
1312 | |
1313 | assert(s); | |
1314 | assert(t); | |
1315 | ||
ef7ce6df DM |
1316 | if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { |
1317 | /* Timeout reached? Increase the timeout for the server used */ | |
1318 | switch (t->scope->protocol) { | |
49cce12d | 1319 | |
ef7ce6df DM |
1320 | case DNS_PROTOCOL_DNS: |
1321 | assert(t->server); | |
3da3cdd5 | 1322 | dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level); |
ef7ce6df | 1323 | break; |
49cce12d | 1324 | |
ef7ce6df DM |
1325 | case DNS_PROTOCOL_LLMNR: |
1326 | case DNS_PROTOCOL_MDNS: | |
1327 | dns_scope_packet_lost(t->scope, usec - t->start_usec); | |
ef7ce6df | 1328 | break; |
49cce12d | 1329 | |
ef7ce6df DM |
1330 | default: |
1331 | assert_not_reached("Invalid DNS protocol."); | |
1332 | } | |
1333 | ||
1334 | if (t->initial_jitter_scheduled) | |
1335 | t->initial_jitter_elapsed = true; | |
be808ea0 TG |
1336 | } |
1337 | ||
423659ab LP |
1338 | log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); |
1339 | ||
d001e0a3 | 1340 | dns_transaction_retry(t, true); |
ec2c5e43 LP |
1341 | return 0; |
1342 | } | |
1343 | ||
9df3ba6c TG |
1344 | static usec_t transaction_get_resend_timeout(DnsTransaction *t) { |
1345 | assert(t); | |
1346 | assert(t->scope); | |
1347 | ||
1348 | switch (t->scope->protocol) { | |
49cce12d | 1349 | |
9df3ba6c | 1350 | case DNS_PROTOCOL_DNS: |
dc349f5f LP |
1351 | |
1352 | /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly | |
1353 | * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that | |
1354 | * needlessly. */ | |
1355 | if (t->stream) | |
1356 | return TRANSACTION_TCP_TIMEOUT_USEC; | |
1357 | ||
dbc4661a | 1358 | return DNS_TIMEOUT_USEC; |
49cce12d | 1359 | |
9df3ba6c | 1360 | case DNS_PROTOCOL_MDNS: |
11a27c2e | 1361 | assert(t->n_attempts > 0); |
53fda2bb DR |
1362 | if (t->probing) |
1363 | return MDNS_PROBING_INTERVAL_USEC; | |
1364 | else | |
1365 | return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; | |
49cce12d | 1366 | |
11a27c2e | 1367 | case DNS_PROTOCOL_LLMNR: |
9df3ba6c | 1368 | return t->scope->resend_timeout; |
49cce12d | 1369 | |
9df3ba6c TG |
1370 | default: |
1371 | assert_not_reached("Invalid DNS protocol."); | |
1372 | } | |
1373 | } | |
1374 | ||
c842ff24 | 1375 | static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { |
ec2c5e43 LP |
1376 | int r; |
1377 | ||
1378 | assert(t); | |
1379 | ||
f535705a | 1380 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 1381 | |
edbcc1fd LP |
1382 | r = dns_scope_network_good(t->scope); |
1383 | if (r < 0) | |
1384 | return r; | |
1385 | if (r == 0) { | |
1386 | dns_transaction_complete(t, DNS_TRANSACTION_NETWORK_DOWN); | |
1387 | return 0; | |
1388 | } | |
1389 | ||
ec2c5e43 LP |
1390 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { |
1391 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1392 | return 0; | |
1393 | } | |
1394 | ||
cbe4216d | 1395 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { |
ec2c5e43 LP |
1396 | /* If we already tried via a stream, then we don't |
1397 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
1398 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1399 | return 0; | |
1400 | } | |
1401 | ||
1402 | t->n_attempts++; | |
9df3ba6c | 1403 | t->start_usec = ts; |
c61d2b44 LP |
1404 | |
1405 | dns_transaction_reset_answer(t); | |
c5b4f861 | 1406 | dns_transaction_flush_dnssec_transactions(t); |
ec2c5e43 | 1407 | |
0d2cd476 LP |
1408 | /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ |
1409 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
8e54f5d9 | 1410 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); |
0d2cd476 LP |
1411 | if (r < 0) |
1412 | return r; | |
1413 | if (r > 0) { | |
1414 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1415 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
931851e8 | 1416 | t->answer_authenticated = true; |
0d2cd476 LP |
1417 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1418 | return 0; | |
1419 | } | |
b2b796b8 | 1420 | |
1c02e7ba | 1421 | if (dns_name_is_root(dns_resource_key_name(t->key)) && |
b2b796b8 LP |
1422 | t->key->type == DNS_TYPE_DS) { |
1423 | ||
1424 | /* Hmm, this is a request for the root DS? A | |
1425 | * DS RR doesn't exist in the root zone, and | |
1426 | * if our trust anchor didn't know it either, | |
1427 | * this means we cannot do any DNSSEC logic | |
1428 | * anymore. */ | |
1429 | ||
1ed8c0fb | 1430 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
b2b796b8 LP |
1431 | /* We are in downgrade mode. In this |
1432 | * case, synthesize an unsigned empty | |
1433 | * response, so that the any lookup | |
1434 | * depending on this one can continue | |
1435 | * assuming there was no DS, and hence | |
1436 | * the root zone was unsigned. */ | |
1437 | ||
1438 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1439 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
1440 | t->answer_authenticated = false; | |
1441 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
1442 | } else | |
1443 | /* If we are not in downgrade mode, | |
1444 | * then fail the lookup, because we | |
1445 | * cannot reasonably answer it. There | |
1446 | * might be DS RRs, but we don't know | |
1447 | * them, and the DNS server won't tell | |
1448 | * them to us (and even if it would, | |
202b76ae | 1449 | * we couldn't validate and trust them. */ |
b2b796b8 LP |
1450 | dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); |
1451 | ||
1452 | return 0; | |
1453 | } | |
0d2cd476 LP |
1454 | } |
1455 | ||
1456 | /* Check the zone, but only if this transaction is not used | |
d746bb3e | 1457 | * for probing or verifying a zone item. */ |
547973de | 1458 | if (set_isempty(t->notify_zone_items)) { |
d746bb3e | 1459 | |
97ebebbc | 1460 | r = dns_zone_lookup(&t->scope->zone, t->key, dns_scope_ifindex(t->scope), &t->answer, NULL, NULL); |
d746bb3e LP |
1461 | if (r < 0) |
1462 | return r; | |
1463 | if (r > 0) { | |
ae6a4bbf | 1464 | t->answer_rcode = DNS_RCODE_SUCCESS; |
c3bc53e6 | 1465 | t->answer_source = DNS_TRANSACTION_ZONE; |
931851e8 | 1466 | t->answer_authenticated = true; |
d746bb3e LP |
1467 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1468 | return 0; | |
1469 | } | |
1470 | } | |
1471 | ||
4d926a69 LP |
1472 | /* Check the cache, but only if this transaction is not used |
1473 | * for probing or verifying a zone item. */ | |
547973de | 1474 | if (set_isempty(t->notify_zone_items)) { |
2c27fbca | 1475 | |
4d926a69 LP |
1476 | /* Before trying the cache, let's make sure we figured out a |
1477 | * server to use. Should this cause a change of server this | |
1478 | * might flush the cache. */ | |
5cdb8930 | 1479 | (void) dns_scope_get_dns_server(t->scope); |
2c27fbca | 1480 | |
4d926a69 LP |
1481 | /* Let's then prune all outdated entries */ |
1482 | dns_cache_prune(&t->scope->cache); | |
1483 | ||
17c8de63 | 1484 | r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); |
4d926a69 LP |
1485 | if (r < 0) |
1486 | return r; | |
1487 | if (r > 0) { | |
c3bc53e6 | 1488 | t->answer_source = DNS_TRANSACTION_CACHE; |
ae6a4bbf | 1489 | if (t->answer_rcode == DNS_RCODE_SUCCESS) |
4d926a69 LP |
1490 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1491 | else | |
3bbdc31d | 1492 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
4d926a69 LP |
1493 | return 0; |
1494 | } | |
ec2c5e43 LP |
1495 | } |
1496 | ||
1effe965 DM |
1497 | return 1; |
1498 | } | |
1499 | ||
0afa57e2 DM |
1500 | static int dns_transaction_make_packet_mdns(DnsTransaction *t) { |
1501 | ||
1502 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
7778dfff | 1503 | bool add_known_answers = false; |
0afa57e2 | 1504 | DnsTransaction *other; |
0d5ee47d DR |
1505 | Iterator i; |
1506 | DnsResourceKey *tkey; | |
1507 | _cleanup_set_free_ Set *keys = NULL; | |
0afa57e2 | 1508 | unsigned qdcount; |
0d5ee47d | 1509 | unsigned nscount = 0; |
0afa57e2 DM |
1510 | usec_t ts; |
1511 | int r; | |
1512 | ||
1513 | assert(t); | |
1514 | assert(t->scope->protocol == DNS_PROTOCOL_MDNS); | |
1515 | ||
e5abebab | 1516 | /* Discard any previously prepared packet, so we can start over and coalesce again */ |
0afa57e2 DM |
1517 | t->sent = dns_packet_unref(t->sent); |
1518 | ||
1519 | r = dns_packet_new_query(&p, t->scope->protocol, 0, false); | |
1520 | if (r < 0) | |
1521 | return r; | |
1522 | ||
58ab31d5 | 1523 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1524 | if (r < 0) |
1525 | return r; | |
1526 | ||
1527 | qdcount = 1; | |
1528 | ||
7778dfff DM |
1529 | if (dns_key_is_shared(t->key)) |
1530 | add_known_answers = true; | |
1531 | ||
0d5ee47d DR |
1532 | if (t->key->type == DNS_TYPE_ANY) { |
1533 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1534 | if (r < 0) | |
1535 | return r; | |
1536 | ||
1537 | r = set_put(keys, t->key); | |
1538 | if (r < 0) | |
1539 | return r; | |
1540 | } | |
1541 | ||
0afa57e2 DM |
1542 | /* |
1543 | * For mDNS, we want to coalesce as many open queries in pending transactions into one single | |
1544 | * query packet on the wire as possible. To achieve that, we iterate through all pending transactions | |
1545 | * in our current scope, and see whether their timing contraints allow them to be sent. | |
1546 | */ | |
1547 | ||
1548 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
1549 | ||
1550 | LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { | |
1551 | ||
1552 | /* Skip ourselves */ | |
1553 | if (other == t) | |
1554 | continue; | |
1555 | ||
1556 | if (other->state != DNS_TRANSACTION_PENDING) | |
1557 | continue; | |
1558 | ||
1559 | if (other->next_attempt_after > ts) | |
1560 | continue; | |
1561 | ||
1562 | if (qdcount >= UINT16_MAX) | |
1563 | break; | |
1564 | ||
58ab31d5 | 1565 | r = dns_packet_append_key(p, other->key, 0, NULL); |
0afa57e2 DM |
1566 | |
1567 | /* | |
1568 | * If we can't stuff more questions into the packet, just give up. | |
1569 | * One of the 'other' transactions will fire later and take care of the rest. | |
1570 | */ | |
1571 | if (r == -EMSGSIZE) | |
1572 | break; | |
1573 | ||
1574 | if (r < 0) | |
1575 | return r; | |
1576 | ||
c842ff24 | 1577 | r = dns_transaction_prepare(other, ts); |
0afa57e2 DM |
1578 | if (r <= 0) |
1579 | continue; | |
1580 | ||
1581 | ts += transaction_get_resend_timeout(other); | |
1582 | ||
1583 | r = sd_event_add_time( | |
1584 | other->scope->manager->event, | |
1585 | &other->timeout_event_source, | |
1586 | clock_boottime_or_monotonic(), | |
1587 | ts, 0, | |
1588 | on_transaction_timeout, other); | |
1589 | if (r < 0) | |
1590 | return r; | |
1591 | ||
ff537038 | 1592 | (void) sd_event_source_set_description(other->timeout_event_source, "dns-transaction-timeout"); |
aa4a9deb | 1593 | |
0afa57e2 DM |
1594 | other->state = DNS_TRANSACTION_PENDING; |
1595 | other->next_attempt_after = ts; | |
1596 | ||
313cefa1 | 1597 | qdcount++; |
7778dfff DM |
1598 | |
1599 | if (dns_key_is_shared(other->key)) | |
1600 | add_known_answers = true; | |
0d5ee47d DR |
1601 | |
1602 | if (other->key->type == DNS_TYPE_ANY) { | |
1603 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1604 | if (r < 0) | |
1605 | return r; | |
1606 | ||
1607 | r = set_put(keys, other->key); | |
1608 | if (r < 0) | |
1609 | return r; | |
1610 | } | |
0afa57e2 DM |
1611 | } |
1612 | ||
1613 | DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); | |
0afa57e2 | 1614 | |
7778dfff DM |
1615 | /* Append known answer section if we're asking for any shared record */ |
1616 | if (add_known_answers) { | |
1617 | r = dns_cache_export_shared_to_packet(&t->scope->cache, p); | |
1618 | if (r < 0) | |
1619 | return r; | |
1620 | } | |
1621 | ||
0d5ee47d DR |
1622 | SET_FOREACH(tkey, keys, i) { |
1623 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; | |
1624 | bool tentative; | |
1625 | ||
1626 | r = dns_zone_lookup(&t->scope->zone, tkey, t->scope->link->ifindex, &answer, NULL, &tentative); | |
1627 | if (r < 0) | |
1628 | return r; | |
1629 | ||
1630 | r = dns_packet_append_answer(p, answer); | |
1631 | if (r < 0) | |
1632 | return r; | |
1633 | ||
1634 | nscount += dns_answer_size(answer); | |
1635 | } | |
1636 | DNS_PACKET_HEADER(p)->nscount = htobe16(nscount); | |
1637 | ||
1cc6c93a | 1638 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1639 | |
1640 | return 0; | |
1641 | } | |
1642 | ||
1643 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
1644 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1645 | int r; | |
1646 | ||
1647 | assert(t); | |
1648 | ||
1649 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) | |
1650 | return dns_transaction_make_packet_mdns(t); | |
1651 | ||
1652 | if (t->sent) | |
1653 | return 0; | |
1654 | ||
b652d4a2 | 1655 | r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); |
0afa57e2 DM |
1656 | if (r < 0) |
1657 | return r; | |
1658 | ||
58ab31d5 | 1659 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1660 | if (r < 0) |
1661 | return r; | |
1662 | ||
1663 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
1664 | DNS_PACKET_HEADER(p)->id = t->id; | |
1665 | ||
1cc6c93a | 1666 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1667 | |
1668 | return 0; | |
1669 | } | |
1670 | ||
1effe965 DM |
1671 | int dns_transaction_go(DnsTransaction *t) { |
1672 | usec_t ts; | |
1673 | int r; | |
202b76ae | 1674 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
1effe965 DM |
1675 | |
1676 | assert(t); | |
1677 | ||
5278bbfe LP |
1678 | /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished |
1679 | * now. */ | |
1680 | ||
1effe965 | 1681 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
547973de | 1682 | |
c842ff24 | 1683 | r = dns_transaction_prepare(t, ts); |
1effe965 DM |
1684 | if (r <= 0) |
1685 | return r; | |
1686 | ||
202b76ae | 1687 | log_debug("Transaction %" PRIu16 " for <%s> scope %s on %s/%s.", |
a5784c49 | 1688 | t->id, |
202b76ae | 1689 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
a5784c49 LP |
1690 | dns_protocol_to_string(t->scope->protocol), |
1691 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 1692 | af_to_name_short(t->scope->family)); |
1effe965 | 1693 | |
ef7ce6df | 1694 | if (!t->initial_jitter_scheduled && |
3742095b | 1695 | IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
ea12bcc7 | 1696 | usec_t jitter, accuracy; |
6e068472 LP |
1697 | |
1698 | /* RFC 4795 Section 2.7 suggests all queries should be | |
1699 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
1700 | ||
ef7ce6df | 1701 | t->initial_jitter_scheduled = true; |
6e068472 LP |
1702 | |
1703 | random_bytes(&jitter, sizeof(jitter)); | |
ea12bcc7 DM |
1704 | |
1705 | switch (t->scope->protocol) { | |
519ef046 | 1706 | |
ea12bcc7 DM |
1707 | case DNS_PROTOCOL_LLMNR: |
1708 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
1709 | accuracy = LLMNR_JITTER_INTERVAL_USEC; | |
1710 | break; | |
519ef046 | 1711 | |
ea12bcc7 DM |
1712 | case DNS_PROTOCOL_MDNS: |
1713 | jitter %= MDNS_JITTER_RANGE_USEC; | |
1714 | jitter += MDNS_JITTER_MIN_USEC; | |
1715 | accuracy = MDNS_JITTER_RANGE_USEC; | |
1716 | break; | |
1717 | default: | |
1718 | assert_not_reached("bad protocol"); | |
1719 | } | |
6e068472 LP |
1720 | |
1721 | r = sd_event_add_time( | |
1722 | t->scope->manager->event, | |
1723 | &t->timeout_event_source, | |
1724 | clock_boottime_or_monotonic(), | |
ea12bcc7 | 1725 | ts + jitter, accuracy, |
6e068472 LP |
1726 | on_transaction_timeout, t); |
1727 | if (r < 0) | |
1728 | return r; | |
1729 | ||
aa4a9deb LP |
1730 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1731 | ||
6e068472 | 1732 | t->n_attempts = 0; |
a9da14e1 | 1733 | t->next_attempt_after = ts; |
6e068472 LP |
1734 | t->state = DNS_TRANSACTION_PENDING; |
1735 | ||
ea12bcc7 | 1736 | log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); |
6e068472 LP |
1737 | return 0; |
1738 | } | |
1739 | ||
ec2c5e43 LP |
1740 | /* Otherwise, we need to ask the network */ |
1741 | r = dns_transaction_make_packet(t); | |
ec2c5e43 LP |
1742 | if (r < 0) |
1743 | return r; | |
1744 | ||
1745 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
1c02e7ba ZJS |
1746 | (dns_name_endswith(dns_resource_key_name(t->key), "in-addr.arpa") > 0 || |
1747 | dns_name_endswith(dns_resource_key_name(t->key), "ip6.arpa") > 0)) { | |
ec2c5e43 LP |
1748 | |
1749 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
1750 | * always be made via TCP on LLMNR */ | |
98767d75 | 1751 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1752 | } else { |
be808ea0 TG |
1753 | /* Try via UDP, and if that fails due to large size or lack of |
1754 | * support try via TCP */ | |
49cce12d | 1755 | r = dns_transaction_emit_udp(t); |
29ab0552 LP |
1756 | if (r == -EMSGSIZE) |
1757 | log_debug("Sending query via TCP since it is too large."); | |
dc349f5f | 1758 | else if (r == -EAGAIN) |
5d67a7ae | 1759 | log_debug("Sending query via TCP since UDP isn't supported."); |
4c701096 | 1760 | if (IN_SET(r, -EMSGSIZE, -EAGAIN)) |
98767d75 | 1761 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1762 | } |
be808ea0 | 1763 | |
ec2c5e43 LP |
1764 | if (r == -ESRCH) { |
1765 | /* No servers to send this to? */ | |
1766 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1767 | return 0; | |
91adc4db LP |
1768 | } |
1769 | if (r == -EOPNOTSUPP) { | |
1770 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1771 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1772 | return 0; | |
1773 | } | |
0791110f | 1774 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(-r)) { |
e94968ba | 1775 | /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot |
0791110f LP |
1776 | * answer this request with this protocol. */ |
1777 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
1778 | return 0; | |
1779 | } | |
91adc4db | 1780 | if (r < 0) { |
7cc6ed7b LP |
1781 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1782 | return r; | |
13b551ac | 1783 | |
ec2c5e43 | 1784 | /* Couldn't send? Try immediately again, with a new server */ |
519ef046 | 1785 | dns_scope_next_dns_server(t->scope); |
ec2c5e43 LP |
1786 | |
1787 | return dns_transaction_go(t); | |
1788 | } | |
1789 | ||
a9da14e1 DM |
1790 | ts += transaction_get_resend_timeout(t); |
1791 | ||
9a015429 LP |
1792 | r = sd_event_add_time( |
1793 | t->scope->manager->event, | |
1794 | &t->timeout_event_source, | |
1795 | clock_boottime_or_monotonic(), | |
a9da14e1 | 1796 | ts, 0, |
9a015429 | 1797 | on_transaction_timeout, t); |
ec2c5e43 LP |
1798 | if (r < 0) |
1799 | return r; | |
1800 | ||
aa4a9deb LP |
1801 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1802 | ||
ec2c5e43 | 1803 | t->state = DNS_TRANSACTION_PENDING; |
a9da14e1 DM |
1804 | t->next_attempt_after = ts; |
1805 | ||
ec2c5e43 LP |
1806 | return 1; |
1807 | } | |
1808 | ||
f2992dc1 LP |
1809 | static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { |
1810 | DnsTransaction *n; | |
1811 | Iterator i; | |
1812 | int r; | |
1813 | ||
1814 | assert(t); | |
1815 | assert(aux); | |
1816 | ||
1817 | /* Try to find cyclic dependencies between transaction objects */ | |
1818 | ||
1819 | if (t == aux) | |
1820 | return 1; | |
1821 | ||
3eb6aa00 | 1822 | SET_FOREACH(n, aux->dnssec_transactions, i) { |
f2992dc1 LP |
1823 | r = dns_transaction_find_cyclic(t, n); |
1824 | if (r != 0) | |
1825 | return r; | |
1826 | } | |
1827 | ||
3eb6aa00 | 1828 | return 0; |
f2992dc1 LP |
1829 | } |
1830 | ||
547973de LP |
1831 | static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { |
1832 | DnsTransaction *aux; | |
1833 | int r; | |
1834 | ||
1835 | assert(t); | |
1836 | assert(ret); | |
1837 | assert(key); | |
1838 | ||
1839 | aux = dns_scope_find_transaction(t->scope, key, true); | |
1840 | if (!aux) { | |
1841 | r = dns_transaction_new(&aux, t->scope, key); | |
1842 | if (r < 0) | |
1843 | return r; | |
1844 | } else { | |
1845 | if (set_contains(t->dnssec_transactions, aux)) { | |
1846 | *ret = aux; | |
1847 | return 0; | |
1848 | } | |
f2992dc1 LP |
1849 | |
1850 | r = dns_transaction_find_cyclic(t, aux); | |
1851 | if (r < 0) | |
1852 | return r; | |
1853 | if (r > 0) { | |
202b76ae ZJS |
1854 | char s[DNS_RESOURCE_KEY_STRING_MAX], saux[DNS_RESOURCE_KEY_STRING_MAX]; |
1855 | ||
1856 | log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", | |
f2992dc1 | 1857 | aux->id, |
202b76ae | 1858 | dns_resource_key_to_string(t->key, s, sizeof s), |
f2992dc1 | 1859 | t->id, |
202b76ae ZJS |
1860 | dns_resource_key_to_string(aux->key, saux, sizeof saux)); |
1861 | ||
f2992dc1 LP |
1862 | return -ELOOP; |
1863 | } | |
547973de LP |
1864 | } |
1865 | ||
1866 | r = set_ensure_allocated(&t->dnssec_transactions, NULL); | |
1867 | if (r < 0) | |
1868 | goto gc; | |
1869 | ||
1870 | r = set_ensure_allocated(&aux->notify_transactions, NULL); | |
1871 | if (r < 0) | |
35aa04e9 LP |
1872 | goto gc; |
1873 | ||
1874 | r = set_ensure_allocated(&aux->notify_transactions_done, NULL); | |
1875 | if (r < 0) | |
547973de LP |
1876 | goto gc; |
1877 | ||
1878 | r = set_put(t->dnssec_transactions, aux); | |
1879 | if (r < 0) | |
1880 | goto gc; | |
1881 | ||
1882 | r = set_put(aux->notify_transactions, t); | |
1883 | if (r < 0) { | |
1884 | (void) set_remove(t->dnssec_transactions, aux); | |
1885 | goto gc; | |
1886 | } | |
1887 | ||
1888 | *ret = aux; | |
1889 | return 1; | |
1890 | ||
1891 | gc: | |
1892 | dns_transaction_gc(aux); | |
1893 | return r; | |
1894 | } | |
1895 | ||
1896 | static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { | |
1897 | _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; | |
1898 | DnsTransaction *aux; | |
1899 | int r; | |
1900 | ||
1901 | assert(t); | |
1902 | assert(key); | |
1903 | ||
1904 | /* Try to get the data from the trust anchor */ | |
8e54f5d9 | 1905 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); |
547973de LP |
1906 | if (r < 0) |
1907 | return r; | |
1908 | if (r > 0) { | |
1909 | r = dns_answer_extend(&t->validated_keys, a); | |
1910 | if (r < 0) | |
1911 | return r; | |
1912 | ||
1913 | return 0; | |
1914 | } | |
1915 | ||
1916 | /* This didn't work, ask for it via the network/cache then. */ | |
1917 | r = dns_transaction_add_dnssec_transaction(t, key, &aux); | |
f2992dc1 LP |
1918 | if (r == -ELOOP) /* This would result in a cyclic dependency */ |
1919 | return 0; | |
547973de LP |
1920 | if (r < 0) |
1921 | return r; | |
1922 | ||
1923 | if (aux->state == DNS_TRANSACTION_NULL) { | |
1924 | r = dns_transaction_go(aux); | |
1925 | if (r < 0) | |
1926 | return r; | |
1927 | } | |
1928 | ||
f2992dc1 | 1929 | return 1; |
547973de LP |
1930 | } |
1931 | ||
8a516214 LP |
1932 | static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { |
1933 | int r; | |
1934 | ||
1935 | assert(t); | |
1936 | ||
c629ff58 | 1937 | /* Check whether the specified name is in the NTA |
8a516214 LP |
1938 | * database, either in the global one, or the link-local |
1939 | * one. */ | |
1940 | ||
1941 | r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); | |
1942 | if (r != 0) | |
1943 | return r; | |
1944 | ||
1945 | if (!t->scope->link) | |
1946 | return 0; | |
1947 | ||
1948 | return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); | |
1949 | } | |
1950 | ||
105e1512 LP |
1951 | static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { |
1952 | int r; | |
1953 | ||
1954 | assert(t); | |
1955 | ||
1956 | /* Checks whether the answer is negative, and lacks NSEC/NSEC3 | |
1957 | * RRs to prove it */ | |
1958 | ||
1959 | r = dns_transaction_has_positive_answer(t, NULL); | |
1960 | if (r < 0) | |
1961 | return r; | |
1962 | if (r > 0) | |
1963 | return false; | |
1964 | ||
8e54f5d9 LP |
1965 | /* Is this key explicitly listed as a negative trust anchor? |
1966 | * If so, it's nothing we need to care about */ | |
1c02e7ba | 1967 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
1968 | if (r < 0) |
1969 | return r; | |
1970 | if (r > 0) | |
1971 | return false; | |
1972 | ||
105e1512 LP |
1973 | /* The answer does not contain any RRs that match to the |
1974 | * question. If so, let's see if there are any NSEC/NSEC3 RRs | |
1975 | * included. If not, the answer is unsigned. */ | |
1976 | ||
1977 | r = dns_answer_contains_nsec_or_nsec3(t->answer); | |
1978 | if (r < 0) | |
1979 | return r; | |
1980 | if (r > 0) | |
1981 | return false; | |
1982 | ||
1983 | return true; | |
1984 | } | |
1985 | ||
1986 | static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { | |
1987 | int r; | |
1988 | ||
1989 | assert(t); | |
1990 | assert(rr); | |
1991 | ||
1992 | /* Check if the specified RR is the "primary" response, | |
1993 | * i.e. either matches the question precisely or is a | |
4cb94977 | 1994 | * CNAME/DNAME for it. */ |
105e1512 LP |
1995 | |
1996 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1997 | if (r != 0) | |
1998 | return r; | |
1999 | ||
4cb94977 | 2000 | return dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); |
105e1512 LP |
2001 | } |
2002 | ||
92ec902a LP |
2003 | static bool dns_transaction_dnssec_supported(DnsTransaction *t) { |
2004 | assert(t); | |
2005 | ||
2006 | /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon | |
2007 | * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ | |
2008 | ||
2009 | if (t->scope->protocol != DNS_PROTOCOL_DNS) | |
2010 | return false; | |
2011 | ||
2012 | /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well | |
2013 | * be supported, hence return true. */ | |
2014 | if (!t->server) | |
2015 | return true; | |
2016 | ||
d001e0a3 LP |
2017 | /* Note that we do not check the feature level actually used for the transaction but instead the feature level |
2018 | * the server is known to support currently, as the transaction feature level might be lower than what the | |
2019 | * server actually supports, since we might have downgraded this transaction's feature level because we got a | |
2020 | * SERVFAIL earlier and wanted to check whether downgrading fixes it. */ | |
92ec902a LP |
2021 | |
2022 | return dns_server_dnssec_supported(t->server); | |
2023 | } | |
2024 | ||
2025 | static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { | |
2026 | DnsTransaction *dt; | |
2027 | Iterator i; | |
2028 | ||
2029 | assert(t); | |
2030 | ||
2031 | /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ | |
2032 | ||
2033 | if (!dns_transaction_dnssec_supported(t)) | |
2034 | return false; | |
2035 | ||
2036 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
2037 | if (!dns_transaction_dnssec_supported(dt)) | |
2038 | return false; | |
2039 | ||
2040 | return true; | |
2041 | } | |
2042 | ||
547973de LP |
2043 | int dns_transaction_request_dnssec_keys(DnsTransaction *t) { |
2044 | DnsResourceRecord *rr; | |
105e1512 | 2045 | |
547973de LP |
2046 | int r; |
2047 | ||
2048 | assert(t); | |
2049 | ||
105e1512 LP |
2050 | /* |
2051 | * Retrieve all auxiliary RRs for the answer we got, so that | |
2052 | * we can verify signatures or prove that RRs are rightfully | |
2053 | * unsigned. Specifically: | |
2054 | * | |
2055 | * - For RRSIG we get the matching DNSKEY | |
2056 | * - For DNSKEY we get the matching DS | |
2057 | * - For unsigned SOA/NS we get the matching DS | |
b63fca62 | 2058 | * - For unsigned CNAME/DNAME/DS we get the parent SOA RR |
105e1512 | 2059 | * - For other unsigned RRs we get the matching SOA RR |
4bbc06cc LP |
2060 | * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR |
2061 | * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR | |
105e1512 LP |
2062 | * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR |
2063 | */ | |
2064 | ||
b652d4a2 | 2065 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de | 2066 | return 0; |
92ec902a LP |
2067 | if (t->answer_source != DNS_TRANSACTION_NETWORK) |
2068 | return 0; /* We only need to validate stuff from the network */ | |
2069 | if (!dns_transaction_dnssec_supported(t)) | |
2070 | return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */ | |
b652d4a2 | 2071 | |
547973de LP |
2072 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2073 | ||
105e1512 LP |
2074 | if (dns_type_is_pseudo(rr->key->type)) |
2075 | continue; | |
2076 | ||
8e54f5d9 | 2077 | /* If this RR is in the negative trust anchor, we don't need to validate it. */ |
1c02e7ba | 2078 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2079 | if (r < 0) |
2080 | return r; | |
2081 | if (r > 0) | |
2082 | continue; | |
2083 | ||
547973de LP |
2084 | switch (rr->key->type) { |
2085 | ||
2086 | case DNS_TYPE_RRSIG: { | |
2087 | /* For each RRSIG we request the matching DNSKEY */ | |
2088 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; | |
2089 | ||
2090 | /* If this RRSIG is about a DNSKEY RR and the | |
2091 | * signer is the same as the owner, then we | |
2092 | * already have the DNSKEY, and we don't have | |
2093 | * to look for more. */ | |
2094 | if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { | |
1c02e7ba | 2095 | r = dns_name_equal(rr->rrsig.signer, dns_resource_key_name(rr->key)); |
547973de LP |
2096 | if (r < 0) |
2097 | return r; | |
2098 | if (r > 0) | |
2099 | continue; | |
2100 | } | |
2101 | ||
105e1512 LP |
2102 | /* If the signer is not a parent of our |
2103 | * original query, then this is about an | |
2104 | * auxiliary RRset, but not anything we asked | |
2105 | * for. In this case we aren't interested, | |
2106 | * because we don't want to request additional | |
2107 | * RRs for stuff we didn't really ask for, and | |
2108 | * also to avoid request loops, where | |
2109 | * additional RRs from one transaction result | |
2110 | * in another transaction whose additonal RRs | |
2111 | * point back to the original transaction, and | |
2112 | * we deadlock. */ | |
1c02e7ba | 2113 | r = dns_name_endswith(dns_resource_key_name(t->key), rr->rrsig.signer); |
547973de LP |
2114 | if (r < 0) |
2115 | return r; | |
2116 | if (r == 0) | |
2117 | continue; | |
2118 | ||
2119 | dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); | |
2120 | if (!dnskey) | |
2121 | return -ENOMEM; | |
2122 | ||
1c02e7ba ZJS |
2123 | log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", |
2124 | t->id, dns_resource_key_name(rr->key), rr->rrsig.key_tag); | |
547973de LP |
2125 | r = dns_transaction_request_dnssec_rr(t, dnskey); |
2126 | if (r < 0) | |
2127 | return r; | |
2128 | break; | |
2129 | } | |
2130 | ||
2131 | case DNS_TYPE_DNSKEY: { | |
2132 | /* For each DNSKEY we request the matching DS */ | |
2133 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2134 | ||
105e1512 LP |
2135 | /* If the DNSKEY we are looking at is not for |
2136 | * zone we are interested in, nor any of its | |
2137 | * parents, we aren't interested, and don't | |
2138 | * request it. After all, we don't want to end | |
2139 | * up in request loops, and want to keep | |
2140 | * additional traffic down. */ | |
2141 | ||
1c02e7ba | 2142 | r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2143 | if (r < 0) |
2144 | return r; | |
2145 | if (r == 0) | |
2146 | continue; | |
2147 | ||
1c02e7ba | 2148 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
547973de LP |
2149 | if (!ds) |
2150 | return -ENOMEM; | |
2151 | ||
1c02e7ba ZJS |
2152 | log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", |
2153 | t->id, dns_resource_key_name(rr->key), dnssec_keytag(rr, false)); | |
105e1512 LP |
2154 | r = dns_transaction_request_dnssec_rr(t, ds); |
2155 | if (r < 0) | |
2156 | return r; | |
547973de | 2157 | |
105e1512 LP |
2158 | break; |
2159 | } | |
2160 | ||
105e1512 LP |
2161 | case DNS_TYPE_SOA: |
2162 | case DNS_TYPE_NS: { | |
2163 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2164 | ||
2165 | /* For an unsigned SOA or NS, try to acquire | |
2166 | * the matching DS RR, as we are at a zone cut | |
2167 | * then, and whether a DS exists tells us | |
2168 | * whether the zone is signed. Do so only if | |
2169 | * this RR matches our original question, | |
2170 | * however. */ | |
2171 | ||
2172 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
2173 | if (r < 0) | |
2174 | return r; | |
6993d264 LP |
2175 | if (r == 0) { |
2176 | /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is | |
2177 | * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry? | |
2178 | * If so, we need to validate it, too. */ | |
2179 | ||
2180 | r = dns_answer_match_key(t->answer, t->key, NULL); | |
2181 | if (r < 0) | |
2182 | return r; | |
2183 | if (r > 0) /* positive reply, we won't need the SOA and hence don't need to validate | |
2184 | * it. */ | |
2185 | continue; | |
2186 | } | |
105e1512 LP |
2187 | |
2188 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2189 | if (r < 0) | |
2190 | return r; | |
2191 | if (r > 0) | |
2192 | continue; | |
2193 | ||
1c02e7ba | 2194 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
105e1512 LP |
2195 | if (!ds) |
2196 | return -ENOMEM; | |
2197 | ||
1c02e7ba ZJS |
2198 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", |
2199 | t->id, dns_resource_key_name(rr->key)); | |
547973de LP |
2200 | r = dns_transaction_request_dnssec_rr(t, ds); |
2201 | if (r < 0) | |
2202 | return r; | |
2203 | ||
2204 | break; | |
105e1512 LP |
2205 | } |
2206 | ||
b63fca62 | 2207 | case DNS_TYPE_DS: |
105e1512 LP |
2208 | case DNS_TYPE_CNAME: |
2209 | case DNS_TYPE_DNAME: { | |
2210 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2211 | const char *name; | |
2212 | ||
2213 | /* CNAMEs and DNAMEs cannot be located at a | |
2214 | * zone apex, hence ask for the parent SOA for | |
2215 | * unsigned CNAME/DNAME RRs, maybe that's the | |
2216 | * apex. But do all that only if this is | |
2217 | * actually a response to our original | |
b63fca62 LP |
2218 | * question. |
2219 | * | |
2220 | * Similar for DS RRs, which are signed when | |
2221 | * the parent SOA is signed. */ | |
105e1512 LP |
2222 | |
2223 | r = dns_transaction_is_primary_response(t, rr); | |
2224 | if (r < 0) | |
2225 | return r; | |
2226 | if (r == 0) | |
2227 | continue; | |
2228 | ||
2229 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2230 | if (r < 0) | |
2231 | return r; | |
2232 | if (r > 0) | |
2233 | continue; | |
2234 | ||
43e6779a LP |
2235 | r = dns_answer_has_dname_for_cname(t->answer, rr); |
2236 | if (r < 0) | |
2237 | return r; | |
2238 | if (r > 0) | |
2239 | continue; | |
2240 | ||
1c02e7ba | 2241 | name = dns_resource_key_name(rr->key); |
105e1512 LP |
2242 | r = dns_name_parent(&name); |
2243 | if (r < 0) | |
2244 | return r; | |
2245 | if (r == 0) | |
2246 | continue; | |
2247 | ||
2248 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); | |
2249 | if (!soa) | |
2250 | return -ENOMEM; | |
2251 | ||
1c02e7ba ZJS |
2252 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", |
2253 | t->id, dns_resource_key_name(rr->key)); | |
105e1512 LP |
2254 | r = dns_transaction_request_dnssec_rr(t, soa); |
2255 | if (r < 0) | |
2256 | return r; | |
2257 | ||
2258 | break; | |
2259 | } | |
2260 | ||
2261 | default: { | |
2262 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2263 | ||
b63fca62 LP |
2264 | /* For other unsigned RRsets (including |
2265 | * NSEC/NSEC3!), look for proof the zone is | |
2266 | * unsigned, by requesting the SOA RR of the | |
2267 | * zone. However, do so only if they are | |
2268 | * directly relevant to our original | |
105e1512 LP |
2269 | * question. */ |
2270 | ||
2271 | r = dns_transaction_is_primary_response(t, rr); | |
2272 | if (r < 0) | |
2273 | return r; | |
2274 | if (r == 0) | |
2275 | continue; | |
2276 | ||
2277 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2278 | if (r < 0) | |
2279 | return r; | |
2280 | if (r > 0) | |
2281 | continue; | |
2282 | ||
1c02e7ba | 2283 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, dns_resource_key_name(rr->key)); |
105e1512 LP |
2284 | if (!soa) |
2285 | return -ENOMEM; | |
2286 | ||
1c02e7ba ZJS |
2287 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", |
2288 | t->id, dns_resource_key_name(rr->key), dns_resource_record_to_string(rr)); | |
105e1512 LP |
2289 | r = dns_transaction_request_dnssec_rr(t, soa); |
2290 | if (r < 0) | |
2291 | return r; | |
2292 | break; | |
547973de LP |
2293 | }} |
2294 | } | |
2295 | ||
105e1512 LP |
2296 | /* Above, we requested everything necessary to validate what |
2297 | * we got. Now, let's request what we need to validate what we | |
2298 | * didn't get... */ | |
2299 | ||
2300 | r = dns_transaction_has_unsigned_negative_answer(t); | |
2301 | if (r < 0) | |
2302 | return r; | |
2303 | if (r > 0) { | |
2304 | const char *name; | |
4bbc06cc | 2305 | uint16_t type = 0; |
105e1512 | 2306 | |
1c02e7ba | 2307 | name = dns_resource_key_name(t->key); |
105e1512 | 2308 | |
4bbc06cc LP |
2309 | /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this |
2310 | * could also be used as indication that we are not at a zone apex, but in real world setups there are | |
2311 | * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even | |
2312 | * though they have further children. If this was a DS request, then it's signed when the parent zone | |
2313 | * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR, | |
2314 | * to see if that is signed. */ | |
105e1512 | 2315 | |
4bbc06cc | 2316 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2317 | r = dns_name_parent(&name); |
4bbc06cc LP |
2318 | if (r > 0) { |
2319 | type = DNS_TYPE_SOA; | |
2320 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty DS response).", | |
1c02e7ba | 2321 | t->id, dns_resource_key_name(t->key)); |
4bbc06cc | 2322 | } else |
105e1512 | 2323 | name = NULL; |
4bbc06cc LP |
2324 | |
2325 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) { | |
2326 | ||
2327 | type = DNS_TYPE_DS; | |
2328 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS response).", | |
2329 | t->id, dns_resource_key_name(t->key)); | |
2330 | ||
2331 | } else { | |
2332 | type = DNS_TYPE_SOA; | |
1c02e7ba ZJS |
2333 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", |
2334 | t->id, dns_resource_key_name(t->key)); | |
4bbc06cc | 2335 | } |
105e1512 LP |
2336 | |
2337 | if (name) { | |
2338 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2339 | ||
4bbc06cc | 2340 | soa = dns_resource_key_new(t->key->class, type, name); |
105e1512 LP |
2341 | if (!soa) |
2342 | return -ENOMEM; | |
2343 | ||
2344 | r = dns_transaction_request_dnssec_rr(t, soa); | |
2345 | if (r < 0) | |
2346 | return r; | |
2347 | } | |
2348 | } | |
2349 | ||
2350 | return dns_transaction_dnssec_is_live(t); | |
547973de LP |
2351 | } |
2352 | ||
2353 | void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { | |
547973de | 2354 | assert(t); |
547973de LP |
2355 | assert(source); |
2356 | ||
942eb2e7 LP |
2357 | /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING, |
2358 | we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If | |
2359 | the state is VALIDATING however, we should check if we are complete now. */ | |
105e1512 | 2360 | |
942eb2e7 LP |
2361 | if (t->state == DNS_TRANSACTION_VALIDATING) |
2362 | dns_transaction_process_dnssec(t); | |
547973de LP |
2363 | } |
2364 | ||
105e1512 LP |
2365 | static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { |
2366 | DnsResourceRecord *rr; | |
2367 | int ifindex, r; | |
2368 | ||
2369 | assert(t); | |
2370 | ||
2371 | /* Add all DNSKEY RRs from the answer that are validated by DS | |
2372 | * RRs from the list of validated keys to the list of | |
2373 | * validated keys. */ | |
2374 | ||
2375 | DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { | |
2376 | ||
96bb7673 | 2377 | r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); |
105e1512 LP |
2378 | if (r < 0) |
2379 | return r; | |
2380 | if (r == 0) | |
2381 | continue; | |
2382 | ||
2383 | /* If so, the DNSKEY is validated too. */ | |
2384 | r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); | |
2385 | if (r < 0) | |
2386 | return r; | |
2387 | } | |
2388 | ||
2389 | return 0; | |
2390 | } | |
2391 | ||
2392 | static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { | |
56352fe9 LP |
2393 | int r; |
2394 | ||
2395 | assert(t); | |
2396 | assert(rr); | |
2397 | ||
105e1512 LP |
2398 | /* Checks if the RR we are looking for must be signed with an |
2399 | * RRSIG. This is used for positive responses. */ | |
24a5b982 | 2400 | |
b652d4a2 | 2401 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2402 | return false; |
56352fe9 | 2403 | |
105e1512 LP |
2404 | if (dns_type_is_pseudo(rr->key->type)) |
2405 | return -EINVAL; | |
56352fe9 | 2406 | |
1c02e7ba | 2407 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2408 | if (r < 0) |
2409 | return r; | |
2410 | if (r > 0) | |
2411 | return false; | |
2412 | ||
105e1512 | 2413 | switch (rr->key->type) { |
56352fe9 | 2414 | |
105e1512 LP |
2415 | case DNS_TYPE_RRSIG: |
2416 | /* RRSIGs are the signatures themselves, they need no signing. */ | |
2417 | return false; | |
2418 | ||
2419 | case DNS_TYPE_SOA: | |
2420 | case DNS_TYPE_NS: { | |
2421 | DnsTransaction *dt; | |
2422 | Iterator i; | |
2423 | ||
b63fca62 | 2424 | /* For SOA or NS RRs we look for a matching DS transaction */ |
105e1512 LP |
2425 | |
2426 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2427 | ||
2428 | if (dt->key->class != rr->key->class) | |
2429 | continue; | |
2430 | if (dt->key->type != DNS_TYPE_DS) | |
2431 | continue; | |
2432 | ||
1c02e7ba | 2433 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2434 | if (r < 0) |
2435 | return r; | |
2436 | if (r == 0) | |
2437 | continue; | |
2438 | ||
2439 | /* We found a DS transactions for the SOA/NS | |
2440 | * RRs we are looking at. If it discovered signed DS | |
2441 | * RRs, then we need to be signed, too. */ | |
2442 | ||
097a2517 TA |
2443 | if (!dt->answer_authenticated) |
2444 | return false; | |
105e1512 | 2445 | |
097a2517 | 2446 | return dns_answer_match_key(dt->answer, dt->key, NULL); |
105e1512 LP |
2447 | } |
2448 | ||
2449 | /* We found nothing that proves this is safe to leave | |
2450 | * this unauthenticated, hence ask inist on | |
2451 | * authentication. */ | |
2452 | return true; | |
2453 | } | |
2454 | ||
b63fca62 | 2455 | case DNS_TYPE_DS: |
105e1512 LP |
2456 | case DNS_TYPE_CNAME: |
2457 | case DNS_TYPE_DNAME: { | |
2458 | const char *parent = NULL; | |
2459 | DnsTransaction *dt; | |
2460 | Iterator i; | |
2461 | ||
b63fca62 LP |
2462 | /* |
2463 | * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. | |
2464 | * | |
2465 | * DS RRs are signed if the parent is signed, hence also look at the parent SOA | |
2466 | */ | |
105e1512 LP |
2467 | |
2468 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2469 | ||
2470 | if (dt->key->class != rr->key->class) | |
2471 | continue; | |
2472 | if (dt->key->type != DNS_TYPE_SOA) | |
2473 | continue; | |
2474 | ||
2475 | if (!parent) { | |
1c02e7ba | 2476 | parent = dns_resource_key_name(rr->key); |
105e1512 LP |
2477 | r = dns_name_parent(&parent); |
2478 | if (r < 0) | |
2479 | return r; | |
2480 | if (r == 0) { | |
b63fca62 LP |
2481 | if (rr->key->type == DNS_TYPE_DS) |
2482 | return true; | |
2483 | ||
105e1512 LP |
2484 | /* A CNAME/DNAME without a parent? That's sooo weird. */ |
2485 | log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); | |
2486 | return -EBADMSG; | |
2487 | } | |
2488 | } | |
2489 | ||
1c02e7ba | 2490 | r = dns_name_equal(dns_resource_key_name(dt->key), parent); |
105e1512 LP |
2491 | if (r < 0) |
2492 | return r; | |
2493 | if (r == 0) | |
2494 | continue; | |
2495 | ||
2496 | return t->answer_authenticated; | |
2497 | } | |
2498 | ||
2499 | return true; | |
2500 | } | |
2501 | ||
2502 | default: { | |
2503 | DnsTransaction *dt; | |
2504 | Iterator i; | |
2505 | ||
b63fca62 | 2506 | /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ |
105e1512 LP |
2507 | |
2508 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2509 | ||
2510 | if (dt->key->class != rr->key->class) | |
2511 | continue; | |
2512 | if (dt->key->type != DNS_TYPE_SOA) | |
2513 | continue; | |
2514 | ||
1c02e7ba | 2515 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2516 | if (r < 0) |
2517 | return r; | |
2518 | if (r == 0) | |
2519 | continue; | |
2520 | ||
2521 | /* We found the transaction that was supposed to find | |
2522 | * the SOA RR for us. It was successful, but found no | |
2523 | * RR for us. This means we are not at a zone cut. In | |
2524 | * this case, we require authentication if the SOA | |
2525 | * lookup was authenticated too. */ | |
2526 | return t->answer_authenticated; | |
2527 | } | |
2528 | ||
2529 | return true; | |
2530 | }} | |
56352fe9 LP |
2531 | } |
2532 | ||
d33b6cf3 LP |
2533 | static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { |
2534 | DnsTransaction *dt; | |
2535 | const char *tld; | |
2536 | Iterator i; | |
2537 | int r; | |
2538 | ||
2539 | /* If DNSSEC downgrade mode is on, checks whether the | |
2540 | * specified RR is one level below a TLD we have proven not to | |
2541 | * exist. In such a case we assume that this is a private | |
2542 | * domain, and permit it. | |
2543 | * | |
2544 | * This detects cases like the Fritz!Box router networks. Each | |
2545 | * Fritz!Box router serves a private "fritz.box" zone, in the | |
2546 | * non-existing TLD "box". Requests for the "fritz.box" domain | |
2547 | * are served by the router itself, while requests for the | |
2548 | * "box" domain will result in NXDOMAIN. | |
2549 | * | |
2550 | * Note that this logic is unable to detect cases where a | |
2551 | * router serves a private DNS zone directly under | |
2552 | * non-existing TLD. In such a case we cannot detect whether | |
2553 | * the TLD is supposed to exist or not, as all requests we | |
2554 | * make for it will be answered by the router's zone, and not | |
2555 | * by the root zone. */ | |
2556 | ||
2557 | assert(t); | |
2558 | ||
2559 | if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) | |
2560 | return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ | |
2561 | ||
1c02e7ba | 2562 | tld = dns_resource_key_name(key); |
d33b6cf3 LP |
2563 | r = dns_name_parent(&tld); |
2564 | if (r < 0) | |
2565 | return r; | |
2566 | if (r == 0) | |
2567 | return false; /* Already the root domain */ | |
2568 | ||
2569 | if (!dns_name_is_single_label(tld)) | |
2570 | return false; | |
2571 | ||
2572 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2573 | ||
2574 | if (dt->key->class != key->class) | |
2575 | continue; | |
2576 | ||
1c02e7ba | 2577 | r = dns_name_equal(dns_resource_key_name(dt->key), tld); |
d33b6cf3 LP |
2578 | if (r < 0) |
2579 | return r; | |
2580 | if (r == 0) | |
2581 | continue; | |
2582 | ||
2583 | /* We found an auxiliary lookup we did for the TLD. If | |
2584 | * that returned with NXDOMAIN, we know the TLD didn't | |
2585 | * exist, and hence this might be a private zone. */ | |
2586 | ||
2587 | return dt->answer_rcode == DNS_RCODE_NXDOMAIN; | |
2588 | } | |
2589 | ||
2590 | return false; | |
2591 | } | |
2592 | ||
105e1512 | 2593 | static int dns_transaction_requires_nsec(DnsTransaction *t) { |
4bbc06cc | 2594 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
105e1512 LP |
2595 | DnsTransaction *dt; |
2596 | const char *name; | |
4bbc06cc | 2597 | uint16_t type = 0; |
105e1512 LP |
2598 | Iterator i; |
2599 | int r; | |
56352fe9 LP |
2600 | |
2601 | assert(t); | |
2602 | ||
105e1512 LP |
2603 | /* Checks if we need to insist on NSEC/NSEC3 RRs for proving |
2604 | * this negative reply */ | |
56352fe9 | 2605 | |
b652d4a2 | 2606 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2607 | return false; |
56352fe9 | 2608 | |
105e1512 LP |
2609 | if (dns_type_is_pseudo(t->key->type)) |
2610 | return -EINVAL; | |
2611 | ||
1c02e7ba | 2612 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
2613 | if (r < 0) |
2614 | return r; | |
2615 | if (r > 0) | |
2616 | return false; | |
2617 | ||
d33b6cf3 LP |
2618 | r = dns_transaction_in_private_tld(t, t->key); |
2619 | if (r < 0) | |
2620 | return r; | |
2621 | if (r > 0) { | |
2622 | /* The lookup is from a TLD that is proven not to | |
2623 | * exist, and we are in downgrade mode, hence ignore | |
13e785f7 | 2624 | * that fact that we didn't get any NSEC RRs. */ |
d33b6cf3 | 2625 | |
202b76ae ZJS |
2626 | log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", |
2627 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
d33b6cf3 LP |
2628 | return false; |
2629 | } | |
2630 | ||
1c02e7ba | 2631 | name = dns_resource_key_name(t->key); |
105e1512 | 2632 | |
4bbc06cc | 2633 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2634 | |
4bbc06cc LP |
2635 | /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed, |
2636 | * hence check the parent SOA in this case. */ | |
105e1512 LP |
2637 | |
2638 | r = dns_name_parent(&name); | |
56352fe9 LP |
2639 | if (r < 0) |
2640 | return r; | |
2641 | if (r == 0) | |
105e1512 | 2642 | return true; |
4bbc06cc LP |
2643 | |
2644 | type = DNS_TYPE_SOA; | |
2645 | ||
2646 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) | |
2647 | /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */ | |
2648 | type = DNS_TYPE_DS; | |
2649 | else | |
2650 | /* For all other negative replies, check for the SOA lookup */ | |
2651 | type = DNS_TYPE_SOA; | |
105e1512 LP |
2652 | |
2653 | /* For all other RRs we check the SOA on the same level to see | |
2654 | * if it's signed. */ | |
2655 | ||
2656 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2657 | ||
2658 | if (dt->key->class != t->key->class) | |
2659 | continue; | |
4bbc06cc | 2660 | if (dt->key->type != type) |
56352fe9 LP |
2661 | continue; |
2662 | ||
1c02e7ba | 2663 | r = dns_name_equal(dns_resource_key_name(dt->key), name); |
56352fe9 LP |
2664 | if (r < 0) |
2665 | return r; | |
105e1512 LP |
2666 | if (r == 0) |
2667 | continue; | |
2668 | ||
2669 | return dt->answer_authenticated; | |
56352fe9 LP |
2670 | } |
2671 | ||
105e1512 LP |
2672 | /* If in doubt, require NSEC/NSEC3 */ |
2673 | return true; | |
56352fe9 LP |
2674 | } |
2675 | ||
94aa7071 LP |
2676 | static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { |
2677 | DnsResourceRecord *rrsig; | |
2678 | bool found = false; | |
2679 | int r; | |
2680 | ||
2681 | /* Checks whether any of the DNSKEYs used for the RRSIGs for | |
2682 | * the specified RRset is authenticated (i.e. has a matching | |
2683 | * DS RR). */ | |
2684 | ||
1c02e7ba | 2685 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2686 | if (r < 0) |
2687 | return r; | |
2688 | if (r > 0) | |
2689 | return false; | |
2690 | ||
94aa7071 LP |
2691 | DNS_ANSWER_FOREACH(rrsig, t->answer) { |
2692 | DnsTransaction *dt; | |
2693 | Iterator i; | |
2694 | ||
2695 | r = dnssec_key_match_rrsig(rr->key, rrsig); | |
2696 | if (r < 0) | |
2697 | return r; | |
2698 | if (r == 0) | |
2699 | continue; | |
2700 | ||
2701 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2702 | ||
2703 | if (dt->key->class != rr->key->class) | |
2704 | continue; | |
2705 | ||
2706 | if (dt->key->type == DNS_TYPE_DNSKEY) { | |
2707 | ||
1c02e7ba | 2708 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2709 | if (r < 0) |
2710 | return r; | |
2711 | if (r == 0) | |
2712 | continue; | |
2713 | ||
2714 | /* OK, we found an auxiliary DNSKEY | |
2715 | * lookup. If that lookup is | |
2716 | * authenticated, report this. */ | |
2717 | ||
2718 | if (dt->answer_authenticated) | |
2719 | return true; | |
2720 | ||
2721 | found = true; | |
2722 | ||
2723 | } else if (dt->key->type == DNS_TYPE_DS) { | |
2724 | ||
1c02e7ba | 2725 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2726 | if (r < 0) |
2727 | return r; | |
2728 | if (r == 0) | |
2729 | continue; | |
2730 | ||
2731 | /* OK, we found an auxiliary DS | |
2732 | * lookup. If that lookup is | |
2733 | * authenticated and non-zero, we | |
2734 | * won! */ | |
2735 | ||
2736 | if (!dt->answer_authenticated) | |
2737 | return false; | |
2738 | ||
2739 | return dns_answer_match_key(dt->answer, dt->key, NULL); | |
2740 | } | |
2741 | } | |
2742 | } | |
2743 | ||
2744 | return found ? false : -ENXIO; | |
2745 | } | |
2746 | ||
b652d4a2 LP |
2747 | static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { |
2748 | assert(t); | |
2749 | assert(rr); | |
2750 | ||
2751 | /* We know that the root domain is signed, hence if it appears | |
2752 | * not to be signed, there's a problem with the DNS server */ | |
2753 | ||
2754 | return rr->key->class == DNS_CLASS_IN && | |
1c02e7ba | 2755 | dns_name_is_root(dns_resource_key_name(rr->key)); |
b652d4a2 LP |
2756 | } |
2757 | ||
0f87f3e8 LP |
2758 | static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { |
2759 | DnsResourceRecord *rr; | |
2760 | int r; | |
2761 | ||
2762 | assert(t); | |
2763 | ||
2764 | /* Maybe warn the user that we encountered a revoked DNSKEY | |
2765 | * for a key from our trust anchor. Note that we don't care | |
2766 | * whether the DNSKEY can be authenticated or not. It's | |
2767 | * sufficient if it is self-signed. */ | |
2768 | ||
2769 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
d424da2a | 2770 | r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); |
0f87f3e8 LP |
2771 | if (r < 0) |
2772 | return r; | |
2773 | } | |
2774 | ||
2775 | return 0; | |
2776 | } | |
2777 | ||
c9c72065 LP |
2778 | static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { |
2779 | bool changed; | |
2780 | int r; | |
2781 | ||
2782 | assert(t); | |
2783 | ||
2784 | /* Removes all DNSKEY/DS objects from t->validated_keys that | |
2785 | * our trust anchors database considers revoked. */ | |
2786 | ||
2787 | do { | |
2788 | DnsResourceRecord *rr; | |
2789 | ||
2790 | changed = false; | |
2791 | ||
2792 | DNS_ANSWER_FOREACH(rr, t->validated_keys) { | |
2793 | r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); | |
2794 | if (r < 0) | |
2795 | return r; | |
2796 | if (r > 0) { | |
2797 | r = dns_answer_remove_by_rr(&t->validated_keys, rr); | |
2798 | if (r < 0) | |
2799 | return r; | |
2800 | ||
2801 | assert(r > 0); | |
2802 | changed = true; | |
2803 | break; | |
2804 | } | |
2805 | } | |
2806 | } while (changed); | |
2807 | ||
2808 | return 0; | |
2809 | } | |
2810 | ||
942eb2e7 LP |
2811 | static int dns_transaction_copy_validated(DnsTransaction *t) { |
2812 | DnsTransaction *dt; | |
2813 | Iterator i; | |
2814 | int r; | |
2815 | ||
2816 | assert(t); | |
2817 | ||
2818 | /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */ | |
2819 | ||
2820 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2821 | ||
2822 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
2823 | continue; | |
2824 | ||
2825 | if (!dt->answer_authenticated) | |
2826 | continue; | |
2827 | ||
2828 | r = dns_answer_extend(&t->validated_keys, dt->answer); | |
2829 | if (r < 0) | |
2830 | return r; | |
2831 | } | |
2832 | ||
2833 | return 0; | |
2834 | } | |
2835 | ||
c690b20a ZJS |
2836 | typedef enum { |
2837 | DNSSEC_PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ | |
2838 | DNSSEC_PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ | |
2839 | DNSSEC_PHASE_ALL, /* Phase #3, validate everything else */ | |
2840 | } Phase; | |
2841 | ||
2842 | static int dnssec_validate_records( | |
2843 | DnsTransaction *t, | |
2844 | Phase phase, | |
2845 | bool *have_nsec, | |
2846 | DnsAnswer **validated) { | |
2847 | ||
547973de | 2848 | DnsResourceRecord *rr; |
56352fe9 | 2849 | int r; |
547973de | 2850 | |
c690b20a | 2851 | /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */ |
547973de | 2852 | |
c690b20a ZJS |
2853 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2854 | DnsResourceRecord *rrsig = NULL; | |
2855 | DnssecResult result; | |
547973de | 2856 | |
c690b20a ZJS |
2857 | switch (rr->key->type) { |
2858 | case DNS_TYPE_RRSIG: | |
2859 | continue; | |
547973de | 2860 | |
c690b20a ZJS |
2861 | case DNS_TYPE_DNSKEY: |
2862 | /* We validate DNSKEYs only in the DNSKEY and ALL phases */ | |
2863 | if (phase == DNSSEC_PHASE_NSEC) | |
2864 | continue; | |
2865 | break; | |
547973de | 2866 | |
c690b20a ZJS |
2867 | case DNS_TYPE_NSEC: |
2868 | case DNS_TYPE_NSEC3: | |
2869 | *have_nsec = true; | |
547973de | 2870 | |
c690b20a ZJS |
2871 | /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ |
2872 | if (phase == DNSSEC_PHASE_DNSKEY) | |
2873 | continue; | |
2874 | break; | |
105e1512 | 2875 | |
c690b20a ZJS |
2876 | default: |
2877 | /* We validate all other RRs only in the ALL phases */ | |
2878 | if (phase != DNSSEC_PHASE_ALL) | |
2879 | continue; | |
2880 | } | |
b652d4a2 | 2881 | |
c690b20a ZJS |
2882 | r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); |
2883 | if (r < 0) | |
2884 | return r; | |
547973de | 2885 | |
c690b20a | 2886 | log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); |
0f87f3e8 | 2887 | |
c690b20a | 2888 | if (result == DNSSEC_VALIDATED) { |
942eb2e7 | 2889 | |
c690b20a ZJS |
2890 | if (rr->key->type == DNS_TYPE_DNSKEY) { |
2891 | /* If we just validated a DNSKEY RRset, then let's add these keys to | |
2892 | * the set of validated keys for this transaction. */ | |
547973de | 2893 | |
c690b20a ZJS |
2894 | r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); |
2895 | if (r < 0) | |
2896 | return r; | |
c9c72065 | 2897 | |
c690b20a ZJS |
2898 | /* Some of the DNSKEYs we just added might already have been revoked, |
2899 | * remove them again in that case. */ | |
2900 | r = dns_transaction_invalidate_revoked_keys(t); | |
2901 | if (r < 0) | |
2902 | return r; | |
2903 | } | |
547973de | 2904 | |
c690b20a ZJS |
2905 | /* Add the validated RRset to the new list of validated |
2906 | * RRsets, and remove it from the unvalidated RRsets. | |
2907 | * We mark the RRset as authenticated and cacheable. */ | |
2908 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); | |
2909 | if (r < 0) | |
2910 | return r; | |
547973de | 2911 | |
c690b20a | 2912 | manager_dnssec_verdict(t->scope->manager, DNSSEC_SECURE, rr->key); |
0c7bff0a | 2913 | |
c690b20a ZJS |
2914 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
2915 | return 1; | |
2916 | } | |
547973de | 2917 | |
c690b20a ZJS |
2918 | /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as |
2919 | * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, | |
2920 | * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ | |
2921 | if (phase != DNSSEC_PHASE_ALL) | |
2922 | continue; | |
0c7bff0a | 2923 | |
c690b20a ZJS |
2924 | if (result == DNSSEC_VALIDATED_WILDCARD) { |
2925 | bool authenticated = false; | |
2926 | const char *source; | |
0c7bff0a | 2927 | |
c690b20a | 2928 | /* This RRset validated, but as a wildcard. This means we need |
13e785f7 | 2929 | * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */ |
0c7bff0a | 2930 | |
c690b20a ZJS |
2931 | /* First step, determine the source of synthesis */ |
2932 | r = dns_resource_record_source(rrsig, &source); | |
2933 | if (r < 0) | |
2934 | return r; | |
0c7bff0a | 2935 | |
c690b20a | 2936 | r = dnssec_test_positive_wildcard(*validated, |
1c02e7ba | 2937 | dns_resource_key_name(rr->key), |
c690b20a ZJS |
2938 | source, |
2939 | rrsig->rrsig.signer, | |
2940 | &authenticated); | |
0c7bff0a | 2941 | |
c690b20a ZJS |
2942 | /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ |
2943 | if (r == 0) | |
2944 | result = DNSSEC_INVALID; | |
2945 | else { | |
2946 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, | |
2947 | authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); | |
2948 | if (r < 0) | |
2949 | return r; | |
2950 | ||
2951 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, rr->key); | |
2952 | ||
2953 | /* Exit the loop, we dropped something from the answer, start from the beginning */ | |
2954 | return 1; | |
0c7bff0a | 2955 | } |
c690b20a | 2956 | } |
0c7bff0a | 2957 | |
c690b20a ZJS |
2958 | if (result == DNSSEC_NO_SIGNATURE) { |
2959 | r = dns_transaction_requires_rrsig(t, rr); | |
547973de LP |
2960 | if (r < 0) |
2961 | return r; | |
c690b20a ZJS |
2962 | if (r == 0) { |
2963 | /* Data does not require signing. In that case, just copy it over, | |
13e785f7 | 2964 | * but remember that this is by no means authenticated. */ |
c690b20a ZJS |
2965 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
2966 | if (r < 0) | |
2967 | return r; | |
2968 | ||
2969 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); | |
2970 | return 1; | |
2971 | } | |
547973de | 2972 | |
c690b20a ZJS |
2973 | r = dns_transaction_known_signed(t, rr); |
2974 | if (r < 0) | |
2975 | return r; | |
2976 | if (r > 0) { | |
2977 | /* This is an RR we know has to be signed. If it isn't this means | |
2978 | * the server is not attaching RRSIGs, hence complain. */ | |
547973de | 2979 | |
c690b20a | 2980 | dns_server_packet_rrsig_missing(t->server, t->current_feature_level); |
547973de | 2981 | |
c690b20a | 2982 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
547973de | 2983 | |
c690b20a | 2984 | /* Downgrading is OK? If so, just consider the information unsigned */ |
c9c72065 | 2985 | |
c690b20a | 2986 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
c9c72065 LP |
2987 | if (r < 0) |
2988 | return r; | |
547973de | 2989 | |
c690b20a ZJS |
2990 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2991 | return 1; | |
2992 | } | |
a150ff5e | 2993 | |
c690b20a ZJS |
2994 | /* Otherwise, fail */ |
2995 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
2996 | return 0; | |
f3cf586d | 2997 | } |
547973de | 2998 | |
c690b20a ZJS |
2999 | r = dns_transaction_in_private_tld(t, rr->key); |
3000 | if (r < 0) | |
3001 | return r; | |
3002 | if (r > 0) { | |
202b76ae | 3003 | char s[DNS_RESOURCE_KEY_STRING_MAX]; |
b652d4a2 | 3004 | |
c690b20a ZJS |
3005 | /* The data is from a TLD that is proven not to exist, and we are in downgrade |
3006 | * mode, hence ignore the fact that this was not signed. */ | |
0c7bff0a | 3007 | |
202b76ae ZJS |
3008 | log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", |
3009 | dns_resource_key_to_string(rr->key, s, sizeof s)); | |
0c7bff0a | 3010 | |
c690b20a | 3011 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
0c7bff0a LP |
3012 | if (r < 0) |
3013 | return r; | |
0c7bff0a | 3014 | |
c690b20a ZJS |
3015 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
3016 | return 1; | |
3017 | } | |
3018 | } | |
0c7bff0a | 3019 | |
c690b20a ZJS |
3020 | if (IN_SET(result, |
3021 | DNSSEC_MISSING_KEY, | |
3022 | DNSSEC_SIGNATURE_EXPIRED, | |
3023 | DNSSEC_UNSUPPORTED_ALGORITHM)) { | |
0c7bff0a | 3024 | |
c690b20a ZJS |
3025 | r = dns_transaction_dnskey_authenticated(t, rr); |
3026 | if (r < 0 && r != -ENXIO) | |
3027 | return r; | |
3028 | if (r == 0) { | |
3029 | /* The DNSKEY transaction was not authenticated, this means there's | |
3030 | * no DS for this, which means it's OK if no keys are found for this signature. */ | |
0c7bff0a | 3031 | |
c690b20a | 3032 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
f3cf586d LP |
3033 | if (r < 0) |
3034 | return r; | |
b652d4a2 | 3035 | |
c690b20a ZJS |
3036 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
3037 | return 1; | |
3038 | } | |
3039 | } | |
b652d4a2 | 3040 | |
c690b20a ZJS |
3041 | r = dns_transaction_is_primary_response(t, rr); |
3042 | if (r < 0) | |
3043 | return r; | |
3044 | if (r > 0) { | |
3045 | /* Look for a matching DNAME for this CNAME */ | |
3046 | r = dns_answer_has_dname_for_cname(t->answer, rr); | |
3047 | if (r < 0) | |
3048 | return r; | |
3049 | if (r == 0) { | |
3050 | /* Also look among the stuff we already validated */ | |
3051 | r = dns_answer_has_dname_for_cname(*validated, rr); | |
f3cf586d LP |
3052 | if (r < 0) |
3053 | return r; | |
c690b20a | 3054 | } |
d33b6cf3 | 3055 | |
c690b20a ZJS |
3056 | if (r == 0) { |
3057 | if (IN_SET(result, | |
3058 | DNSSEC_INVALID, | |
3059 | DNSSEC_SIGNATURE_EXPIRED, | |
3060 | DNSSEC_NO_SIGNATURE)) | |
3061 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, rr->key); | |
3062 | else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ | |
3063 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, rr->key); | |
3064 | ||
3065 | /* This is a primary response to our question, and it failed validation. | |
3066 | * That's fatal. */ | |
3067 | t->answer_dnssec_result = result; | |
3068 | return 0; | |
3069 | } | |
d33b6cf3 | 3070 | |
c690b20a ZJS |
3071 | /* This is a primary response, but we do have a DNAME RR |
3072 | * in the RR that can replay this CNAME, hence rely on | |
3073 | * that, and we can remove the CNAME in favour of it. */ | |
3074 | } | |
d33b6cf3 | 3075 | |
c690b20a ZJS |
3076 | /* This is just some auxiliary data. Just remove the RRset and continue. */ |
3077 | r = dns_answer_remove_by_key(&t->answer, rr->key); | |
3078 | if (r < 0) | |
3079 | return r; | |
d33b6cf3 | 3080 | |
c690b20a ZJS |
3081 | /* We dropped something from the answer, start from the beginning. */ |
3082 | return 1; | |
3083 | } | |
f3cf586d | 3084 | |
c690b20a ZJS |
3085 | return 2; /* Finito. */ |
3086 | } | |
94aa7071 | 3087 | |
c690b20a ZJS |
3088 | int dns_transaction_validate_dnssec(DnsTransaction *t) { |
3089 | _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; | |
3090 | Phase phase; | |
3091 | DnsAnswerFlags flags; | |
3092 | int r; | |
202b76ae | 3093 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
94aa7071 | 3094 | |
c690b20a | 3095 | assert(t); |
94aa7071 | 3096 | |
c690b20a ZJS |
3097 | /* We have now collected all DS and DNSKEY RRs in |
3098 | * t->validated_keys, let's see which RRs we can now | |
3099 | * authenticate with that. */ | |
94aa7071 | 3100 | |
c690b20a ZJS |
3101 | if (t->scope->dnssec_mode == DNSSEC_NO) |
3102 | return 0; | |
a150ff5e | 3103 | |
c690b20a ZJS |
3104 | /* Already validated */ |
3105 | if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) | |
3106 | return 0; | |
105e1512 | 3107 | |
c690b20a ZJS |
3108 | /* Our own stuff needs no validation */ |
3109 | if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { | |
3110 | t->answer_dnssec_result = DNSSEC_VALIDATED; | |
3111 | t->answer_authenticated = true; | |
3112 | return 0; | |
3113 | } | |
a150ff5e | 3114 | |
c690b20a ZJS |
3115 | /* Cached stuff is not affected by validation. */ |
3116 | if (t->answer_source != DNS_TRANSACTION_NETWORK) | |
3117 | return 0; | |
f3cf586d | 3118 | |
c690b20a ZJS |
3119 | if (!dns_transaction_dnssec_supported_full(t)) { |
3120 | /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ | |
3121 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
d001e0a3 | 3122 | log_debug("Not validating response for %" PRIu16 ", used server feature level does not support DNSSEC.", t->id); |
c690b20a ZJS |
3123 | return 0; |
3124 | } | |
f3cf586d | 3125 | |
202b76ae ZJS |
3126 | log_debug("Validating response from transaction %" PRIu16 " (%s).", |
3127 | t->id, | |
3128 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
547973de | 3129 | |
c690b20a ZJS |
3130 | /* First, see if this response contains any revoked trust |
3131 | * anchors we care about */ | |
3132 | r = dns_transaction_check_revoked_trust_anchors(t); | |
3133 | if (r < 0) | |
3134 | return r; | |
43e6779a | 3135 | |
c690b20a ZJS |
3136 | /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */ |
3137 | r = dns_transaction_copy_validated(t); | |
3138 | if (r < 0) | |
3139 | return r; | |
43e6779a | 3140 | |
c690b20a ZJS |
3141 | /* Second, see if there are DNSKEYs we already know a |
3142 | * validated DS for. */ | |
3143 | r = dns_transaction_validate_dnskey_by_ds(t); | |
3144 | if (r < 0) | |
3145 | return r; | |
43e6779a | 3146 | |
c690b20a ZJS |
3147 | /* Fourth, remove all DNSKEY and DS RRs again that our trust |
3148 | * anchor says are revoked. After all we might have marked | |
3149 | * some keys revoked above, but they might still be lingering | |
3150 | * in our validated_keys list. */ | |
3151 | r = dns_transaction_invalidate_revoked_keys(t); | |
3152 | if (r < 0) | |
3153 | return r; | |
f3cf586d | 3154 | |
c690b20a ZJS |
3155 | phase = DNSSEC_PHASE_DNSKEY; |
3156 | for (;;) { | |
3157 | bool have_nsec = false; | |
f3cf586d | 3158 | |
c690b20a ZJS |
3159 | r = dnssec_validate_records(t, phase, &have_nsec, &validated); |
3160 | if (r <= 0) | |
3161 | return r; | |
547973de | 3162 | |
c690b20a ZJS |
3163 | /* Try again as long as we managed to achieve something */ |
3164 | if (r == 1) | |
547973de LP |
3165 | continue; |
3166 | ||
c690b20a | 3167 | if (phase == DNSSEC_PHASE_DNSKEY && have_nsec) { |
0c7bff0a | 3168 | /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ |
c690b20a | 3169 | phase = DNSSEC_PHASE_NSEC; |
0c7bff0a LP |
3170 | continue; |
3171 | } | |
3172 | ||
c690b20a ZJS |
3173 | if (phase != DNSSEC_PHASE_ALL) { |
3174 | /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. | |
3175 | * Note that in this third phase we start to remove RRs we couldn't validate. */ | |
3176 | phase = DNSSEC_PHASE_ALL; | |
56352fe9 | 3177 | continue; |
547973de LP |
3178 | } |
3179 | ||
56352fe9 | 3180 | /* We're done */ |
547973de LP |
3181 | break; |
3182 | } | |
3183 | ||
3184 | dns_answer_unref(t->answer); | |
1cc6c93a | 3185 | t->answer = TAKE_PTR(validated); |
547973de | 3186 | |
72667f08 LP |
3187 | /* At this point the answer only contains validated |
3188 | * RRsets. Now, let's see if it actually answers the question | |
3189 | * we asked. If so, great! If it doesn't, then see if | |
3190 | * NSEC/NSEC3 can prove this. */ | |
105e1512 | 3191 | r = dns_transaction_has_positive_answer(t, &flags); |
72667f08 | 3192 | if (r > 0) { |
105e1512 LP |
3193 | /* Yes, it answers the question! */ |
3194 | ||
3195 | if (flags & DNS_ANSWER_AUTHENTICATED) { | |
3196 | /* The answer is fully authenticated, yay. */ | |
019036a4 | 3197 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
105e1512 LP |
3198 | t->answer_rcode = DNS_RCODE_SUCCESS; |
3199 | t->answer_authenticated = true; | |
3200 | } else { | |
3201 | /* The answer is not fully authenticated. */ | |
019036a4 | 3202 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
3203 | t->answer_authenticated = false; |
3204 | } | |
3205 | ||
72667f08 LP |
3206 | } else if (r == 0) { |
3207 | DnssecNsecResult nr; | |
ed29bfdc | 3208 | bool authenticated = false; |
72667f08 LP |
3209 | |
3210 | /* Bummer! Let's check NSEC/NSEC3 */ | |
0c7bff0a | 3211 | r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); |
72667f08 LP |
3212 | if (r < 0) |
3213 | return r; | |
3214 | ||
3215 | switch (nr) { | |
3216 | ||
3217 | case DNSSEC_NSEC_NXDOMAIN: | |
3218 | /* NSEC proves the domain doesn't exist. Very good. */ | |
202b76ae | 3219 | log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3220 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3221 | t->answer_rcode = DNS_RCODE_NXDOMAIN; |
ed29bfdc | 3222 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3223 | |
59c5b597 | 3224 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3225 | break; |
3226 | ||
3227 | case DNSSEC_NSEC_NODATA: | |
3228 | /* NSEC proves that there's no data here, very good. */ | |
202b76ae | 3229 | log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3230 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3231 | t->answer_rcode = DNS_RCODE_SUCCESS; |
ed29bfdc | 3232 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3233 | |
59c5b597 | 3234 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3235 | break; |
3236 | ||
105e1512 LP |
3237 | case DNSSEC_NSEC_OPTOUT: |
3238 | /* NSEC3 says the data might not be signed */ | |
202b76ae | 3239 | log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3240 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3241 | t->answer_authenticated = false; |
7aa8ce98 | 3242 | |
59c5b597 | 3243 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3244 | break; |
3245 | ||
72667f08 LP |
3246 | case DNSSEC_NSEC_NO_RR: |
3247 | /* No NSEC data? Bummer! */ | |
105e1512 LP |
3248 | |
3249 | r = dns_transaction_requires_nsec(t); | |
3250 | if (r < 0) | |
3251 | return r; | |
7aa8ce98 | 3252 | if (r > 0) { |
019036a4 | 3253 | t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; |
59c5b597 | 3254 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
7aa8ce98 | 3255 | } else { |
019036a4 | 3256 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3257 | t->answer_authenticated = false; |
59c5b597 | 3258 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3259 | } |
3260 | ||
3261 | break; | |
3262 | ||
3263 | case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: | |
3264 | /* We don't know the NSEC3 algorithm used? */ | |
019036a4 | 3265 | t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; |
59c5b597 | 3266 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, t->key); |
72667f08 LP |
3267 | break; |
3268 | ||
3269 | case DNSSEC_NSEC_FOUND: | |
146035b3 | 3270 | case DNSSEC_NSEC_CNAME: |
72667f08 | 3271 | /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ |
019036a4 | 3272 | t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; |
59c5b597 | 3273 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
72667f08 LP |
3274 | break; |
3275 | ||
3276 | default: | |
3277 | assert_not_reached("Unexpected NSEC result."); | |
3278 | } | |
3279 | } | |
3280 | ||
547973de LP |
3281 | return 1; |
3282 | } | |
3283 | ||
ec2c5e43 LP |
3284 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { |
3285 | [DNS_TRANSACTION_NULL] = "null", | |
3286 | [DNS_TRANSACTION_PENDING] = "pending", | |
547973de | 3287 | [DNS_TRANSACTION_VALIDATING] = "validating", |
3bbdc31d | 3288 | [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", |
ec2c5e43 LP |
3289 | [DNS_TRANSACTION_SUCCESS] = "success", |
3290 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
3291 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
3292 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
3293 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
7cc6ed7b | 3294 | [DNS_TRANSACTION_ERRNO] = "errno", |
ec2c5e43 | 3295 | [DNS_TRANSACTION_ABORTED] = "aborted", |
547973de | 3296 | [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", |
b2b796b8 | 3297 | [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", |
91adc4db | 3298 | [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", |
edbcc1fd | 3299 | [DNS_TRANSACTION_NETWORK_DOWN] = "network-down", |
0791110f | 3300 | [DNS_TRANSACTION_NOT_FOUND] = "not-found", |
ec2c5e43 LP |
3301 | }; |
3302 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); | |
c3bc53e6 LP |
3303 | |
3304 | static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { | |
3305 | [DNS_TRANSACTION_NETWORK] = "network", | |
3306 | [DNS_TRANSACTION_CACHE] = "cache", | |
3307 | [DNS_TRANSACTION_ZONE] = "zone", | |
0d2cd476 | 3308 | [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", |
c3bc53e6 LP |
3309 | }; |
3310 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); |