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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" | |
56ddbf10 | 14 | #if ENABLE_DNS_OVER_TLS |
6016fcb0 | 15 | #include "resolved-dnstls.h" |
5d67a7ae | 16 | #endif |
6016fcb0 | 17 | #include "string-table.h" |
5d67a7ae | 18 | |
b214dc0f | 19 | #define TRANSACTIONS_MAX 4096 |
dc349f5f | 20 | #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC) |
b214dc0f | 21 | |
dbc4661a MCO |
22 | /* After how much time to repeat classic DNS requests */ |
23 | #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX) | |
24 | ||
c61d2b44 LP |
25 | static void dns_transaction_reset_answer(DnsTransaction *t) { |
26 | assert(t); | |
27 | ||
28 | t->received = dns_packet_unref(t->received); | |
29 | t->answer = dns_answer_unref(t->answer); | |
30 | t->answer_rcode = 0; | |
31 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; | |
32 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; | |
33 | t->answer_authenticated = false; | |
d3760be0 | 34 | t->answer_nsec_ttl = (uint32_t) -1; |
7cc6ed7b | 35 | t->answer_errno = 0; |
c61d2b44 LP |
36 | } |
37 | ||
c5b4f861 LP |
38 | static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { |
39 | DnsTransaction *z; | |
40 | ||
41 | assert(t); | |
42 | ||
43 | while ((z = set_steal_first(t->dnssec_transactions))) { | |
44 | set_remove(z->notify_transactions, t); | |
35aa04e9 | 45 | set_remove(z->notify_transactions_done, t); |
c5b4f861 LP |
46 | dns_transaction_gc(z); |
47 | } | |
48 | } | |
49 | ||
f32f0e57 LP |
50 | static void dns_transaction_close_connection(DnsTransaction *t) { |
51 | assert(t); | |
52 | ||
b30bf55d LP |
53 | if (t->stream) { |
54 | /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ | |
98767d75 IT |
55 | LIST_REMOVE(transactions_by_stream, t->stream->transactions, t); |
56 | ||
57 | /* Remove packet in case it's still in the queue */ | |
58 | dns_packet_unref(ordered_set_remove(t->stream->write_queue, t->sent)); | |
59 | ||
b30bf55d LP |
60 | t->stream = dns_stream_unref(t->stream); |
61 | } | |
62 | ||
f32f0e57 LP |
63 | t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); |
64 | t->dns_udp_fd = safe_close(t->dns_udp_fd); | |
65 | } | |
66 | ||
f535705a | 67 | static void dns_transaction_stop_timeout(DnsTransaction *t) { |
97cc656c LP |
68 | assert(t); |
69 | ||
70 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
97cc656c LP |
71 | } |
72 | ||
ec2c5e43 | 73 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { |
801ad6a6 | 74 | DnsQueryCandidate *c; |
ec2c5e43 | 75 | DnsZoneItem *i; |
547973de | 76 | DnsTransaction *z; |
ec2c5e43 LP |
77 | |
78 | if (!t) | |
79 | return NULL; | |
80 | ||
51e399bc LP |
81 | log_debug("Freeing transaction %" PRIu16 ".", t->id); |
82 | ||
f32f0e57 | 83 | dns_transaction_close_connection(t); |
f535705a | 84 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 85 | |
ec2c5e43 | 86 | dns_packet_unref(t->sent); |
c61d2b44 | 87 | dns_transaction_reset_answer(t); |
ec2c5e43 | 88 | |
8300ba21 | 89 | dns_server_unref(t->server); |
ec2c5e43 LP |
90 | |
91 | if (t->scope) { | |
f9ebb22a LP |
92 | hashmap_remove_value(t->scope->transactions_by_key, t->key, t); |
93 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
ec2c5e43 LP |
94 | |
95 | if (t->id != 0) | |
96 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
97 | } | |
98 | ||
547973de | 99 | while ((c = set_steal_first(t->notify_query_candidates))) |
801ad6a6 | 100 | set_remove(c->transactions, t); |
547973de | 101 | set_free(t->notify_query_candidates); |
801ad6a6 | 102 | |
35aa04e9 LP |
103 | while ((c = set_steal_first(t->notify_query_candidates_done))) |
104 | set_remove(c->transactions, t); | |
105 | set_free(t->notify_query_candidates_done); | |
106 | ||
547973de | 107 | while ((i = set_steal_first(t->notify_zone_items))) |
ec2c5e43 | 108 | i->probe_transaction = NULL; |
547973de LP |
109 | set_free(t->notify_zone_items); |
110 | ||
35aa04e9 LP |
111 | while ((i = set_steal_first(t->notify_zone_items_done))) |
112 | i->probe_transaction = NULL; | |
113 | set_free(t->notify_zone_items_done); | |
114 | ||
547973de LP |
115 | while ((z = set_steal_first(t->notify_transactions))) |
116 | set_remove(z->dnssec_transactions, t); | |
117 | set_free(t->notify_transactions); | |
118 | ||
35aa04e9 LP |
119 | while ((z = set_steal_first(t->notify_transactions_done))) |
120 | set_remove(z->dnssec_transactions, t); | |
121 | set_free(t->notify_transactions_done); | |
122 | ||
c5b4f861 | 123 | dns_transaction_flush_dnssec_transactions(t); |
547973de LP |
124 | set_free(t->dnssec_transactions); |
125 | ||
126 | dns_answer_unref(t->validated_keys); | |
97cc656c | 127 | dns_resource_key_unref(t->key); |
97cc656c | 128 | |
6b430fdb | 129 | return mfree(t); |
ec2c5e43 LP |
130 | } |
131 | ||
132 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
133 | ||
51e399bc | 134 | bool dns_transaction_gc(DnsTransaction *t) { |
ec2c5e43 LP |
135 | assert(t); |
136 | ||
137 | if (t->block_gc > 0) | |
51e399bc | 138 | return true; |
ec2c5e43 | 139 | |
547973de | 140 | if (set_isempty(t->notify_query_candidates) && |
35aa04e9 | 141 | set_isempty(t->notify_query_candidates_done) && |
547973de | 142 | set_isempty(t->notify_zone_items) && |
35aa04e9 LP |
143 | set_isempty(t->notify_zone_items_done) && |
144 | set_isempty(t->notify_transactions) && | |
145 | set_isempty(t->notify_transactions_done)) { | |
ec2c5e43 | 146 | dns_transaction_free(t); |
51e399bc LP |
147 | return false; |
148 | } | |
149 | ||
150 | return true; | |
ec2c5e43 LP |
151 | } |
152 | ||
4dd15077 LP |
153 | static uint16_t pick_new_id(Manager *m) { |
154 | uint16_t new_id; | |
155 | ||
156 | /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of | |
157 | * transactions, and it's much lower than the space of IDs. */ | |
158 | ||
159 | assert_cc(TRANSACTIONS_MAX < 0xFFFF); | |
160 | ||
161 | do | |
162 | random_bytes(&new_id, sizeof(new_id)); | |
163 | while (new_id == 0 || | |
164 | hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id))); | |
165 | ||
166 | return new_id; | |
167 | } | |
168 | ||
f52e61da | 169 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { |
ec2c5e43 LP |
170 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; |
171 | int r; | |
172 | ||
173 | assert(ret); | |
174 | assert(s); | |
f52e61da | 175 | assert(key); |
ec2c5e43 | 176 | |
9eae2bf3 | 177 | /* Don't allow looking up invalid or pseudo RRs */ |
c463eb78 | 178 | if (!dns_type_is_valid_query(key->type)) |
9eae2bf3 | 179 | return -EINVAL; |
d0129ddb LP |
180 | if (dns_type_is_obsolete(key->type)) |
181 | return -EOPNOTSUPP; | |
9eae2bf3 LP |
182 | |
183 | /* We only support the IN class */ | |
4c701096 | 184 | if (!IN_SET(key->class, DNS_CLASS_IN, DNS_CLASS_ANY)) |
9eae2bf3 LP |
185 | return -EOPNOTSUPP; |
186 | ||
b214dc0f LP |
187 | if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX) |
188 | return -EBUSY; | |
189 | ||
d5099efc | 190 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
191 | if (r < 0) |
192 | return r; | |
193 | ||
f9ebb22a | 194 | r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); |
da0c630e LP |
195 | if (r < 0) |
196 | return r; | |
197 | ||
ec2c5e43 LP |
198 | t = new0(DnsTransaction, 1); |
199 | if (!t) | |
200 | return -ENOMEM; | |
201 | ||
4667e00a | 202 | t->dns_udp_fd = -1; |
c3bc53e6 | 203 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; |
019036a4 | 204 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
d3760be0 | 205 | t->answer_nsec_ttl = (uint32_t) -1; |
f52e61da | 206 | t->key = dns_resource_key_ref(key); |
274b8748 | 207 | t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
d001e0a3 | 208 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
ec2c5e43 | 209 | |
4dd15077 | 210 | t->id = pick_new_id(s->manager); |
ec2c5e43 LP |
211 | |
212 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
213 | if (r < 0) { | |
214 | t->id = 0; | |
215 | return r; | |
216 | } | |
217 | ||
f9ebb22a | 218 | r = hashmap_replace(s->transactions_by_key, t->key, t); |
da0c630e LP |
219 | if (r < 0) { |
220 | hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
221 | return r; | |
222 | } | |
223 | ||
f9ebb22a | 224 | LIST_PREPEND(transactions_by_scope, s->transactions, t); |
ec2c5e43 LP |
225 | t->scope = s; |
226 | ||
313cefa1 | 227 | s->manager->n_transactions_total++; |
a150ff5e | 228 | |
ec2c5e43 LP |
229 | if (ret) |
230 | *ret = t; | |
231 | ||
232 | t = NULL; | |
233 | ||
234 | return 0; | |
235 | } | |
236 | ||
4dd15077 LP |
237 | static void dns_transaction_shuffle_id(DnsTransaction *t) { |
238 | uint16_t new_id; | |
239 | assert(t); | |
240 | ||
241 | /* Pick a new ID for this transaction. */ | |
242 | ||
243 | new_id = pick_new_id(t->scope->manager); | |
244 | assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0); | |
245 | ||
246 | log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id); | |
247 | t->id = new_id; | |
248 | ||
249 | /* Make sure we generate a new packet with the new ID */ | |
250 | t->sent = dns_packet_unref(t->sent); | |
251 | } | |
252 | ||
ec2c5e43 | 253 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { |
2fb3034c | 254 | _cleanup_free_ char *pretty = NULL; |
202b76ae | 255 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 | 256 | DnsZoneItem *z; |
ec2c5e43 LP |
257 | |
258 | assert(t); | |
259 | assert(p); | |
260 | ||
261 | if (manager_our_packet(t->scope->manager, p) != 0) | |
262 | return; | |
263 | ||
164d025d | 264 | (void) in_addr_to_string(p->family, &p->sender, &pretty); |
2fb3034c | 265 | |
a5784c49 LP |
266 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", |
267 | t->id, | |
202b76ae | 268 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
269 | dns_protocol_to_string(t->scope->protocol), |
270 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 271 | af_to_name_short(t->scope->family), |
164d025d | 272 | strnull(pretty)); |
ec2c5e43 | 273 | |
a4076574 LP |
274 | /* RFC 4795, Section 4.1 says that the peer with the |
275 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
276 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
277 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
278 | return; |
279 | } | |
280 | ||
4d91eec4 | 281 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 282 | |
ec2c5e43 | 283 | t->block_gc++; |
35aa04e9 | 284 | |
547973de | 285 | while ((z = set_first(t->notify_zone_items))) { |
3ef64445 LP |
286 | /* First, make sure the zone item drops the reference |
287 | * to us */ | |
288 | dns_zone_item_probe_stop(z); | |
289 | ||
290 | /* Secondly, report this as conflict, so that we might | |
291 | * look for a different hostname */ | |
ec2c5e43 | 292 | dns_zone_item_conflict(z); |
3ef64445 | 293 | } |
ec2c5e43 LP |
294 | t->block_gc--; |
295 | ||
296 | dns_transaction_gc(t); | |
297 | } | |
298 | ||
299 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
801ad6a6 | 300 | DnsQueryCandidate *c; |
ec2c5e43 | 301 | DnsZoneItem *z; |
547973de | 302 | DnsTransaction *d; |
7cc6ed7b | 303 | const char *st; |
202b76ae | 304 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 LP |
305 | |
306 | assert(t); | |
547973de | 307 | assert(!DNS_TRANSACTION_IS_LIVE(state)); |
e56187ca | 308 | |
202b76ae ZJS |
309 | if (state == DNS_TRANSACTION_DNSSEC_FAILED) { |
310 | dns_resource_key_to_string(t->key, key_str, sizeof key_str); | |
311 | ||
f61dfddb | 312 | log_struct(LOG_NOTICE, |
2b044526 | 313 | "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR, |
202b76ae | 314 | LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str, dnssec_result_to_string(t->answer_dnssec_result)), |
f61dfddb | 315 | "DNS_TRANSACTION=%" PRIu16, t->id, |
202b76ae | 316 | "DNS_QUESTION=%s", key_str, |
f61dfddb | 317 | "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), |
1e02e182 | 318 | "DNS_SERVER=%s", dns_server_string(t->server), |
a1230ff9 | 319 | "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t->server->possible_feature_level)); |
202b76ae | 320 | } |
f61dfddb | 321 | |
ec2c5e43 LP |
322 | /* Note that this call might invalidate the query. Callers |
323 | * should hence not attempt to access the query or transaction | |
324 | * after calling this function. */ | |
325 | ||
7cc6ed7b LP |
326 | if (state == DNS_TRANSACTION_ERRNO) |
327 | st = errno_to_name(t->answer_errno); | |
328 | else | |
329 | st = dns_transaction_state_to_string(state); | |
330 | ||
a5784c49 LP |
331 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", |
332 | t->id, | |
202b76ae | 333 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 LP |
334 | dns_protocol_to_string(t->scope->protocol), |
335 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 336 | af_to_name_short(t->scope->family), |
7cc6ed7b | 337 | st, |
a5784c49 LP |
338 | t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), |
339 | t->answer_authenticated ? "authenticated" : "unsigned"); | |
ec2c5e43 LP |
340 | |
341 | t->state = state; | |
342 | ||
f32f0e57 | 343 | dns_transaction_close_connection(t); |
f535705a | 344 | dns_transaction_stop_timeout(t); |
ec2c5e43 LP |
345 | |
346 | /* Notify all queries that are interested, but make sure the | |
347 | * transaction isn't freed while we are still looking at it */ | |
348 | t->block_gc++; | |
f7014757 | 349 | |
35aa04e9 | 350 | SET_FOREACH_MOVE(c, t->notify_query_candidates_done, t->notify_query_candidates) |
547973de | 351 | dns_query_candidate_notify(c); |
35aa04e9 | 352 | SWAP_TWO(t->notify_query_candidates, t->notify_query_candidates_done); |
ec2c5e43 | 353 | |
35aa04e9 LP |
354 | SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items) |
355 | dns_zone_item_notify(z); | |
356 | SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done); | |
8d67e72c | 357 | if (t->probing && t->state == DNS_TRANSACTION_ATTEMPTS_MAX_REACHED) |
1a63fc54 | 358 | (void) dns_scope_announce(t->scope, false); |
f7014757 | 359 | |
35aa04e9 LP |
360 | SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions) |
361 | dns_transaction_notify(d, t); | |
362 | SWAP_TWO(t->notify_transactions, t->notify_transactions_done); | |
f7014757 LP |
363 | |
364 | t->block_gc--; | |
ec2c5e43 LP |
365 | dns_transaction_gc(t); |
366 | } | |
367 | ||
519ef046 LP |
368 | static int dns_transaction_pick_server(DnsTransaction *t) { |
369 | DnsServer *server; | |
370 | ||
371 | assert(t); | |
372 | assert(t->scope->protocol == DNS_PROTOCOL_DNS); | |
373 | ||
d001e0a3 LP |
374 | /* Pick a DNS server and a feature level for it. */ |
375 | ||
519ef046 LP |
376 | server = dns_scope_get_dns_server(t->scope); |
377 | if (!server) | |
378 | return -ESRCH; | |
379 | ||
d001e0a3 LP |
380 | /* If we changed the server invalidate the feature level clamping, as the new server might have completely |
381 | * different properties. */ | |
382 | if (server != t->server) | |
383 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; | |
384 | ||
274b8748 | 385 | t->current_feature_level = dns_server_possible_feature_level(server); |
519ef046 | 386 | |
d001e0a3 LP |
387 | /* Clamp the feature level if that is requested. */ |
388 | if (t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID && | |
389 | t->current_feature_level > t->clamp_feature_level) | |
390 | t->current_feature_level = t->clamp_feature_level; | |
391 | ||
392 | log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t->current_feature_level), t->id); | |
393 | ||
519ef046 LP |
394 | if (server == t->server) |
395 | return 0; | |
396 | ||
397 | dns_server_unref(t->server); | |
398 | t->server = dns_server_ref(server); | |
399 | ||
44db02d0 LP |
400 | t->n_picked_servers ++; |
401 | ||
d001e0a3 LP |
402 | log_debug("Using DNS server %s for transaction %u.", dns_server_string(t->server), t->id); |
403 | ||
519ef046 LP |
404 | return 1; |
405 | } | |
406 | ||
d001e0a3 | 407 | static void dns_transaction_retry(DnsTransaction *t, bool next_server) { |
8d10d620 LP |
408 | int r; |
409 | ||
410 | assert(t); | |
411 | ||
412 | log_debug("Retrying transaction %" PRIu16 ".", t->id); | |
413 | ||
414 | /* Before we try again, switch to a new server. */ | |
d001e0a3 LP |
415 | if (next_server) |
416 | dns_scope_next_dns_server(t->scope); | |
8d10d620 LP |
417 | |
418 | r = dns_transaction_go(t); | |
7cc6ed7b LP |
419 | if (r < 0) { |
420 | t->answer_errno = -r; | |
421 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
422 | } | |
8d10d620 LP |
423 | } |
424 | ||
c02cf2f4 | 425 | static int dns_transaction_maybe_restart(DnsTransaction *t) { |
5278bbfe LP |
426 | int r; |
427 | ||
c02cf2f4 LP |
428 | assert(t); |
429 | ||
5278bbfe LP |
430 | /* Returns > 0 if the transaction was restarted, 0 if not */ |
431 | ||
c02cf2f4 LP |
432 | if (!t->server) |
433 | return 0; | |
434 | ||
435 | if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) | |
436 | return 0; | |
437 | ||
438 | /* The server's current feature level is lower than when we sent the original query. We learnt something from | |
439 | the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to | |
440 | restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include | |
441 | OPT RR or DO bit. One of these cases is documented here, for example: | |
442 | https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ | |
443 | ||
4dd15077 LP |
444 | log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID."); |
445 | dns_transaction_shuffle_id(t); | |
5278bbfe LP |
446 | |
447 | r = dns_transaction_go(t); | |
448 | if (r < 0) | |
449 | return r; | |
450 | ||
451 | return 1; | |
c02cf2f4 LP |
452 | } |
453 | ||
98767d75 IT |
454 | static void on_transaction_stream_error(DnsTransaction *t, int error) { |
455 | assert(t); | |
ec2c5e43 | 456 | |
b30bf55d | 457 | dns_transaction_close_connection(t); |
ec2c5e43 | 458 | |
a1a3f73a | 459 | if (ERRNO_IS_DISCONNECT(error)) { |
0791110f LP |
460 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { |
461 | /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the | |
462 | * question on this scope. */ | |
463 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
daab72ea | 464 | return; |
0791110f LP |
465 | } |
466 | ||
d001e0a3 | 467 | dns_transaction_retry(t, true); |
daab72ea | 468 | return; |
ac720200 | 469 | } |
ec2c5e43 | 470 | if (error != 0) { |
7cc6ed7b LP |
471 | t->answer_errno = error; |
472 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 | 473 | } |
98767d75 IT |
474 | } |
475 | ||
476 | static int dns_transaction_on_stream_packet(DnsTransaction *t, DnsPacket *p) { | |
477 | assert(t); | |
478 | assert(p); | |
479 | ||
480 | dns_transaction_close_connection(t); | |
ec2c5e43 | 481 | |
a4076574 | 482 | if (dns_packet_validate_reply(p) <= 0) { |
a20b9592 | 483 | log_debug("Invalid TCP reply packet."); |
a4076574 LP |
484 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
485 | return 0; | |
486 | } | |
487 | ||
488 | dns_scope_check_conflicts(t->scope, p); | |
489 | ||
ec2c5e43 LP |
490 | t->block_gc++; |
491 | dns_transaction_process_reply(t, p); | |
492 | t->block_gc--; | |
493 | ||
519ef046 LP |
494 | /* If the response wasn't useful, then complete the transition |
495 | * now. After all, we are the worst feature set now with TCP | |
496 | * sockets, and there's really no point in retrying. */ | |
ec2c5e43 LP |
497 | if (t->state == DNS_TRANSACTION_PENDING) |
498 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
598f44bd LP |
499 | else |
500 | dns_transaction_gc(t); | |
ec2c5e43 LP |
501 | |
502 | return 0; | |
503 | } | |
504 | ||
98767d75 | 505 | static int on_stream_complete(DnsStream *s, int error) { |
18df5fb0 | 506 | _cleanup_(dns_stream_unrefp) DnsStream *p = NULL; |
98767d75 IT |
507 | DnsTransaction *t, *n; |
508 | int r = 0; | |
509 | ||
510 | /* Do not let new transactions use this stream */ | |
511 | if (s->server && s->server->stream == s) | |
18df5fb0 | 512 | p = TAKE_PTR(s->server->stream); |
98767d75 IT |
513 | |
514 | if (ERRNO_IS_DISCONNECT(error) && s->protocol != DNS_PROTOCOL_LLMNR) { | |
515 | usec_t usec; | |
516 | ||
517 | log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); | |
518 | ||
519 | if (s->transactions) { | |
520 | t = s->transactions; | |
521 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); | |
3da3cdd5 | 522 | dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level); |
98767d75 IT |
523 | } |
524 | } | |
525 | ||
526 | LIST_FOREACH_SAFE(transactions_by_stream, t, n, s->transactions) | |
527 | if (error != 0) | |
528 | on_transaction_stream_error(t, error); | |
529 | else if (DNS_PACKET_ID(s->read_packet) == t->id) | |
530 | /* As each transaction have a unique id the return code is only set once */ | |
531 | r = dns_transaction_on_stream_packet(t, s->read_packet); | |
532 | ||
533 | return r; | |
534 | } | |
535 | ||
536 | static int dns_stream_on_packet(DnsStream *s) { | |
537 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
538 | int r = 0; | |
539 | DnsTransaction *t; | |
540 | ||
541 | /* Take ownership of packet to be able to receive new packets */ | |
542 | p = TAKE_PTR(s->read_packet); | |
543 | s->n_read = 0; | |
544 | ||
545 | t = hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); | |
546 | ||
547 | /* Ignore incorrect transaction id as transaction can have been canceled */ | |
548 | if (t) | |
549 | r = dns_transaction_on_stream_packet(t, p); | |
550 | else { | |
551 | if (dns_packet_validate_reply(p) <= 0) { | |
552 | log_debug("Invalid TCP reply packet."); | |
553 | on_stream_complete(s, 0); | |
554 | } | |
555 | return 0; | |
556 | } | |
557 | ||
558 | return r; | |
559 | } | |
560 | ||
561 | static int dns_transaction_emit_tcp(DnsTransaction *t) { | |
ec2c5e43 | 562 | _cleanup_close_ int fd = -1; |
98767d75 | 563 | _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; |
91ccab1e | 564 | union sockaddr_union sa; |
ec2c5e43 LP |
565 | int r; |
566 | ||
567 | assert(t); | |
568 | ||
519ef046 | 569 | dns_transaction_close_connection(t); |
ec2c5e43 | 570 | |
106784eb | 571 | switch (t->scope->protocol) { |
519ef046 | 572 | |
106784eb | 573 | case DNS_PROTOCOL_DNS: |
519ef046 LP |
574 | r = dns_transaction_pick_server(t); |
575 | if (r < 0) | |
576 | return r; | |
577 | ||
92ec902a | 578 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
579 | return -EOPNOTSUPP; |
580 | ||
274b8748 | 581 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
582 | if (r < 0) |
583 | return r; | |
584 | ||
5d67a7ae | 585 | if (t->server->stream && (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level) == t->server->stream->encrypted)) |
98767d75 IT |
586 | s = dns_stream_ref(t->server->stream); |
587 | else | |
5d67a7ae | 588 | 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 | 589 | |
106784eb | 590 | break; |
ec2c5e43 | 591 | |
106784eb | 592 | case DNS_PROTOCOL_LLMNR: |
a8f6397f | 593 | /* When we already received a reply to this (but it was truncated), send to its sender address */ |
ec2c5e43 | 594 | if (t->received) |
91ccab1e | 595 | fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port, &sa); |
ec2c5e43 LP |
596 | else { |
597 | union in_addr_union address; | |
a7f7d1bd | 598 | int family = AF_UNSPEC; |
ec2c5e43 LP |
599 | |
600 | /* Otherwise, try to talk to the owner of a | |
601 | * the IP address, in case this is a reverse | |
602 | * PTR lookup */ | |
f52e61da | 603 | |
1c02e7ba | 604 | r = dns_name_address(dns_resource_key_name(t->key), &family, &address); |
ec2c5e43 LP |
605 | if (r < 0) |
606 | return r; | |
607 | if (r == 0) | |
608 | return -EINVAL; | |
9e08a6e0 | 609 | if (family != t->scope->family) |
9318cdd3 | 610 | return -ESRCH; |
ec2c5e43 | 611 | |
91ccab1e | 612 | fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT, &sa); |
ec2c5e43 | 613 | } |
106784eb DM |
614 | |
615 | break; | |
616 | ||
617 | default: | |
ec2c5e43 | 618 | return -EAFNOSUPPORT; |
106784eb | 619 | } |
ec2c5e43 | 620 | |
98767d75 IT |
621 | if (!s) { |
622 | if (fd < 0) | |
623 | return fd; | |
ec2c5e43 | 624 | |
91ccab1e | 625 | r = dns_stream_new(t->scope->manager, &s, t->scope->protocol, fd, &sa); |
98767d75 IT |
626 | if (r < 0) |
627 | return r; | |
628 | ||
629 | fd = -1; | |
630 | ||
56ddbf10 | 631 | #if ENABLE_DNS_OVER_TLS |
5d67a7ae | 632 | if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) { |
b02a7e1a | 633 | assert(t->server); |
6016fcb0 | 634 | r = dnstls_stream_connect_tls(s, t->server); |
5d67a7ae IT |
635 | if (r < 0) |
636 | return r; | |
637 | } | |
638 | #endif | |
639 | ||
19feb28f IT |
640 | if (t->server) { |
641 | dns_stream_unref(t->server->stream); | |
642 | t->server->stream = dns_stream_ref(s); | |
643 | s->server = dns_server_ref(t->server); | |
644 | } | |
645 | ||
98767d75 IT |
646 | s->complete = on_stream_complete; |
647 | s->on_packet = dns_stream_on_packet; | |
648 | ||
649 | /* The interface index is difficult to determine if we are | |
650 | * connecting to the local host, hence fill this in right away | |
651 | * instead of determining it from the socket */ | |
652 | s->ifindex = dns_scope_ifindex(t->scope); | |
653 | } | |
654 | ||
655 | t->stream = TAKE_PTR(s); | |
656 | LIST_PREPEND(transactions_by_stream, t->stream->transactions, t); | |
ec2c5e43 LP |
657 | |
658 | r = dns_stream_write_packet(t->stream, t->sent); | |
659 | if (r < 0) { | |
98767d75 | 660 | dns_transaction_close_connection(t); |
ec2c5e43 LP |
661 | return r; |
662 | } | |
663 | ||
519ef046 LP |
664 | dns_transaction_reset_answer(t); |
665 | ||
cbe4216d LP |
666 | t->tried_stream = true; |
667 | ||
ec2c5e43 LP |
668 | return 0; |
669 | } | |
670 | ||
547973de | 671 | static void dns_transaction_cache_answer(DnsTransaction *t) { |
547973de LP |
672 | assert(t); |
673 | ||
674 | /* For mDNS we cache whenever we get the packet, rather than | |
675 | * in each transaction. */ | |
676 | if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) | |
677 | return; | |
678 | ||
ceeddf79 MP |
679 | /* Caching disabled? */ |
680 | if (!t->scope->manager->enable_cache) | |
681 | return; | |
682 | ||
547973de LP |
683 | /* We never cache if this packet is from the local host, under |
684 | * the assumption that a locally running DNS server would | |
685 | * cache this anyway, and probably knows better when to flush | |
686 | * the cache then we could. */ | |
687 | if (!DNS_PACKET_SHALL_CACHE(t->received)) | |
688 | return; | |
689 | ||
547973de LP |
690 | dns_cache_put(&t->scope->cache, |
691 | t->key, | |
692 | t->answer_rcode, | |
693 | t->answer, | |
547973de | 694 | t->answer_authenticated, |
d3760be0 | 695 | t->answer_nsec_ttl, |
547973de LP |
696 | 0, |
697 | t->received->family, | |
698 | &t->received->sender); | |
699 | } | |
700 | ||
105e1512 LP |
701 | static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { |
702 | DnsTransaction *dt; | |
703 | Iterator i; | |
704 | ||
705 | assert(t); | |
706 | ||
707 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
708 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
709 | return true; | |
710 | ||
711 | return false; | |
712 | } | |
713 | ||
942eb2e7 LP |
714 | static int dns_transaction_dnssec_ready(DnsTransaction *t) { |
715 | DnsTransaction *dt; | |
716 | Iterator i; | |
717 | ||
718 | assert(t); | |
719 | ||
720 | /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still | |
721 | * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */ | |
722 | ||
723 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
724 | ||
725 | switch (dt->state) { | |
726 | ||
727 | case DNS_TRANSACTION_NULL: | |
728 | case DNS_TRANSACTION_PENDING: | |
729 | case DNS_TRANSACTION_VALIDATING: | |
730 | /* Still ongoing */ | |
731 | return 0; | |
732 | ||
733 | case DNS_TRANSACTION_RCODE_FAILURE: | |
b3c6b00a | 734 | if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) { |
942eb2e7 LP |
735 | log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode)); |
736 | goto fail; | |
737 | } | |
738 | ||
b3c6b00a LP |
739 | /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers |
740 | * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS | |
741 | * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar | |
742 | * RRs to make unsigned proofs. */ | |
942eb2e7 LP |
743 | |
744 | case DNS_TRANSACTION_SUCCESS: | |
745 | /* All good. */ | |
746 | break; | |
747 | ||
748 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
749 | /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC | |
750 | * validationr result */ | |
751 | ||
752 | log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result)); | |
753 | t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */ | |
754 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
755 | return 0; | |
756 | ||
942eb2e7 LP |
757 | default: |
758 | log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state)); | |
759 | goto fail; | |
760 | } | |
761 | } | |
762 | ||
763 | /* All is ready, we can go and validate */ | |
764 | return 1; | |
765 | ||
766 | fail: | |
767 | t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; | |
768 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
769 | return 0; | |
770 | } | |
771 | ||
547973de LP |
772 | static void dns_transaction_process_dnssec(DnsTransaction *t) { |
773 | int r; | |
774 | ||
775 | assert(t); | |
776 | ||
777 | /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ | |
942eb2e7 | 778 | r = dns_transaction_dnssec_ready(t); |
7cc6ed7b LP |
779 | if (r < 0) |
780 | goto fail; | |
942eb2e7 | 781 | if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */ |
547973de LP |
782 | return; |
783 | ||
c02cf2f4 LP |
784 | /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better |
785 | * restart the lookup immediately. */ | |
786 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
787 | if (r < 0) |
788 | goto fail; | |
c02cf2f4 LP |
789 | if (r > 0) /* Transaction got restarted... */ |
790 | return; | |
791 | ||
547973de LP |
792 | /* All our auxiliary DNSSEC transactions are complete now. Try |
793 | * to validate our RRset now. */ | |
794 | r = dns_transaction_validate_dnssec(t); | |
fcfaff12 LP |
795 | if (r == -EBADMSG) { |
796 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
797 | return; | |
798 | } | |
7cc6ed7b LP |
799 | if (r < 0) |
800 | goto fail; | |
547973de | 801 | |
b652d4a2 LP |
802 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && |
803 | t->scope->dnssec_mode == DNSSEC_YES) { | |
e82b1132 LP |
804 | |
805 | /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe | |
806 | * that works. */ | |
807 | ||
808 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { | |
809 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
810 | dns_transaction_retry(t, true); | |
811 | return; | |
812 | } | |
813 | ||
814 | /* OK, let's give up, apparently all servers we tried didn't work. */ | |
b652d4a2 LP |
815 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
816 | return; | |
817 | } | |
818 | ||
019036a4 | 819 | if (!IN_SET(t->answer_dnssec_result, |
b652d4a2 LP |
820 | _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ |
821 | DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ | |
822 | DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ | |
823 | DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ | |
547973de LP |
824 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
825 | return; | |
826 | } | |
827 | ||
1e02e182 LP |
828 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER) |
829 | dns_server_warn_downgrade(t->server); | |
830 | ||
547973de LP |
831 | dns_transaction_cache_answer(t); |
832 | ||
833 | if (t->answer_rcode == DNS_RCODE_SUCCESS) | |
834 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
835 | else | |
3bbdc31d | 836 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
7cc6ed7b LP |
837 | |
838 | return; | |
839 | ||
840 | fail: | |
841 | t->answer_errno = -r; | |
842 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
547973de LP |
843 | } |
844 | ||
eac7cda2 LP |
845 | static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { |
846 | int r; | |
847 | ||
848 | assert(t); | |
849 | ||
850 | /* Checks whether the answer is positive, i.e. either a direct | |
851 | * answer to the question, or a CNAME/DNAME for it */ | |
852 | ||
853 | r = dns_answer_match_key(t->answer, t->key, flags); | |
854 | if (r != 0) | |
855 | return r; | |
856 | ||
857 | r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); | |
858 | if (r != 0) | |
859 | return r; | |
860 | ||
861 | return false; | |
862 | } | |
863 | ||
864 | static int dns_transaction_fix_rcode(DnsTransaction *t) { | |
865 | int r; | |
866 | ||
867 | assert(t); | |
868 | ||
869 | /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the | |
870 | * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a | |
871 | * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first | |
872 | * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when | |
873 | * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle | |
874 | * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a | |
875 | * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server | |
876 | * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an | |
877 | * incomplete CNAME/DNAME chain. | |
878 | * | |
879 | * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS, | |
880 | * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new | |
881 | * lookup. */ | |
882 | ||
883 | if (t->answer_rcode != DNS_RCODE_NXDOMAIN) | |
884 | return 0; | |
885 | ||
886 | r = dns_transaction_has_positive_answer(t, NULL); | |
887 | if (r <= 0) | |
888 | return r; | |
889 | ||
890 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
891 | return 0; | |
892 | } | |
893 | ||
ec2c5e43 | 894 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { |
9df3ba6c | 895 | usec_t ts; |
ec2c5e43 LP |
896 | int r; |
897 | ||
898 | assert(t); | |
899 | assert(p); | |
9df3ba6c TG |
900 | assert(t->scope); |
901 | assert(t->scope->manager); | |
ec2c5e43 | 902 | |
5a7e41a3 LP |
903 | if (t->state != DNS_TRANSACTION_PENDING) |
904 | return; | |
905 | ||
ec2c5e43 LP |
906 | /* Note that this call might invalidate the query. Callers |
907 | * should hence not attempt to access the query or transaction | |
908 | * after calling this function. */ | |
909 | ||
11833205 ZJS |
910 | log_debug("Processing incoming packet on transaction %" PRIu16" (rcode=%s).", |
911 | t->id, dns_rcode_to_string(DNS_PACKET_RCODE(p))); | |
b5efcf29 | 912 | |
106784eb | 913 | switch (t->scope->protocol) { |
b5efcf29 | 914 | |
106784eb | 915 | case DNS_PROTOCOL_LLMNR: |
97ebebbc | 916 | /* For LLMNR we will not accept any packets from other interfaces */ |
ec2c5e43 | 917 | |
97ebebbc | 918 | if (p->ifindex != dns_scope_ifindex(t->scope)) |
ec2c5e43 LP |
919 | return; |
920 | ||
921 | if (p->family != t->scope->family) | |
922 | return; | |
923 | ||
924 | /* Tentative packets are not full responses but still | |
925 | * useful for identifying uniqueness conflicts during | |
926 | * probing. */ | |
8b757a38 | 927 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
928 | dns_transaction_tentative(t, p); |
929 | return; | |
930 | } | |
106784eb DM |
931 | |
932 | break; | |
933 | ||
4e5bf5e1 | 934 | case DNS_PROTOCOL_MDNS: |
4e5bf5e1 | 935 | /* For mDNS we will not accept any packets from other interfaces */ |
97ebebbc LP |
936 | |
937 | if (p->ifindex != dns_scope_ifindex(t->scope)) | |
4e5bf5e1 DM |
938 | return; |
939 | ||
940 | if (p->family != t->scope->family) | |
941 | return; | |
942 | ||
943 | break; | |
944 | ||
106784eb | 945 | case DNS_PROTOCOL_DNS: |
8ad182a1 LP |
946 | /* Note that we do not need to verify the |
947 | * addresses/port numbers of incoming traffic, as we | |
948 | * invoked connect() on our UDP socket in which case | |
949 | * the kernel already does the needed verification for | |
950 | * us. */ | |
106784eb DM |
951 | break; |
952 | ||
953 | default: | |
9c56a6f3 | 954 | assert_not_reached("Invalid DNS protocol."); |
ec2c5e43 LP |
955 | } |
956 | ||
ec2c5e43 LP |
957 | if (t->received != p) { |
958 | dns_packet_unref(t->received); | |
959 | t->received = dns_packet_ref(p); | |
960 | } | |
961 | ||
c3bc53e6 LP |
962 | t->answer_source = DNS_TRANSACTION_NETWORK; |
963 | ||
ec2c5e43 LP |
964 | if (p->ipproto == IPPROTO_TCP) { |
965 | if (DNS_PACKET_TC(p)) { | |
966 | /* Truncated via TCP? Somebody must be fucking with us */ | |
967 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
968 | return; | |
969 | } | |
970 | ||
971 | if (DNS_PACKET_ID(p) != t->id) { | |
972 | /* Not the reply to our query? Somebody must be fucking with us */ | |
973 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
974 | return; | |
975 | } | |
976 | } | |
977 | ||
38a03f06 | 978 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
9df3ba6c TG |
979 | |
980 | switch (t->scope->protocol) { | |
8af5b883 | 981 | |
9df3ba6c TG |
982 | case DNS_PROTOCOL_DNS: |
983 | assert(t->server); | |
984 | ||
4e0b8b17 TG |
985 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { |
986 | ||
8af5b883 | 987 | /* Request failed, immediately try again with reduced features */ |
4e0b8b17 | 988 | |
7d581a65 | 989 | if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) { |
44db02d0 | 990 | |
7d581a65 | 991 | /* This was already at UDP feature level? If so, it doesn't make sense to downgrade |
44db02d0 LP |
992 | * this transaction anymore, but let's see if it might make sense to send the request |
993 | * to a different DNS server instead. If not let's process the response, and accept the | |
7d581a65 LP |
994 | * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate |
995 | * packet loss, but is not going to give us better rcodes should we actually have | |
996 | * managed to get them already at UDP level. */ | |
997 | ||
44db02d0 LP |
998 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { |
999 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
1000 | dns_transaction_retry(t, true); | |
1001 | return; | |
1002 | } | |
1003 | ||
1004 | /* Give up, accept the rcode */ | |
d001e0a3 LP |
1005 | log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
1006 | break; | |
1007 | } | |
1008 | ||
1009 | /* Reduce this feature level by one and try again. */ | |
5d67a7ae IT |
1010 | switch (t->current_feature_level) { |
1011 | case DNS_SERVER_FEATURE_LEVEL_TLS_DO: | |
1012 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN; | |
1013 | break; | |
1014 | case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN + 1: | |
1015 | /* Skip plain TLS when TLS is not supported */ | |
1016 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN - 1; | |
1017 | break; | |
1018 | default: | |
1019 | t->clamp_feature_level = t->current_feature_level - 1; | |
1020 | } | |
d001e0a3 LP |
1021 | |
1022 | log_debug("Server returned error %s, retrying transaction with reduced feature level %s.", | |
1023 | dns_rcode_to_string(DNS_PACKET_RCODE(p)), | |
1024 | dns_server_feature_level_to_string(t->clamp_feature_level)); | |
1025 | ||
1026 | dns_transaction_retry(t, false /* use the same server */); | |
4e0b8b17 | 1027 | return; |
eb08640a LP |
1028 | } |
1029 | ||
1030 | if (DNS_PACKET_RCODE(p) == DNS_RCODE_REFUSED) { | |
1031 | /* This server refused our request? If so, try again, use a different server */ | |
1032 | log_debug("Server returned REFUSED, switching servers, and retrying."); | |
1033 | dns_transaction_retry(t, true /* pick a new server */); | |
1034 | return; | |
1035 | } | |
1036 | ||
1037 | if (DNS_PACKET_TC(p)) | |
274b8748 | 1038 | dns_server_packet_truncated(t->server, t->current_feature_level); |
9df3ba6c TG |
1039 | |
1040 | break; | |
8af5b883 | 1041 | |
9df3ba6c TG |
1042 | case DNS_PROTOCOL_LLMNR: |
1043 | case DNS_PROTOCOL_MDNS: | |
1044 | dns_scope_packet_received(t->scope, ts - t->start_usec); | |
9df3ba6c | 1045 | break; |
8af5b883 | 1046 | |
9df3ba6c | 1047 | default: |
8af5b883 | 1048 | assert_not_reached("Invalid DNS protocol."); |
9df3ba6c TG |
1049 | } |
1050 | ||
ec2c5e43 | 1051 | if (DNS_PACKET_TC(p)) { |
547493c5 DM |
1052 | |
1053 | /* Truncated packets for mDNS are not allowed. Give up immediately. */ | |
1054 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) { | |
1055 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1056 | return; | |
1057 | } | |
1058 | ||
f757cd85 LP |
1059 | log_debug("Reply truncated, retrying via TCP."); |
1060 | ||
ec2c5e43 | 1061 | /* Response was truncated, let's try again with good old TCP */ |
98767d75 | 1062 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 LP |
1063 | if (r == -ESRCH) { |
1064 | /* No servers found? Damn! */ | |
1065 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1066 | return; | |
1067 | } | |
91adc4db LP |
1068 | if (r == -EOPNOTSUPP) { |
1069 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1070 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1071 | return; | |
1072 | } | |
ec2c5e43 | 1073 | if (r < 0) { |
8af5b883 | 1074 | /* On LLMNR, if we cannot connect to the host, |
ec2c5e43 | 1075 | * we immediately give up */ |
7cc6ed7b LP |
1076 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1077 | goto fail; | |
ec2c5e43 LP |
1078 | |
1079 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
d001e0a3 | 1080 | dns_transaction_retry(t, true); |
ec2c5e43 | 1081 | } |
2a6658ef LP |
1082 | |
1083 | return; | |
ec2c5e43 LP |
1084 | } |
1085 | ||
de54e62b | 1086 | /* After the superficial checks, actually parse the message. */ |
ec2c5e43 LP |
1087 | r = dns_packet_extract(p); |
1088 | if (r < 0) { | |
1089 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1090 | return; | |
1091 | } | |
1092 | ||
ed9717fc | 1093 | if (t->server) { |
d001e0a3 LP |
1094 | /* Report that we successfully received a valid packet with a good rcode after we initially got a bad |
1095 | * rcode and subsequently downgraded the protocol */ | |
1096 | ||
1097 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN) && | |
1098 | t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID) | |
1099 | dns_server_packet_rcode_downgrade(t->server, t->clamp_feature_level); | |
1100 | ||
1101 | /* Report that the OPT RR was missing */ | |
ed9717fc LP |
1102 | if (!p->opt) |
1103 | dns_server_packet_bad_opt(t->server, t->current_feature_level); | |
1104 | ||
d001e0a3 | 1105 | /* Report that we successfully received a packet */ |
dbc4661a | 1106 | dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, p->size); |
ed9717fc | 1107 | } |
de54e62b | 1108 | |
c02cf2f4 LP |
1109 | /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ |
1110 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
1111 | if (r < 0) |
1112 | goto fail; | |
c02cf2f4 LP |
1113 | if (r > 0) /* Transaction got restarted... */ |
1114 | return; | |
1115 | ||
8b419837 | 1116 | if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
b5efcf29 | 1117 | |
8b419837 DR |
1118 | /* When dealing with protocols other than mDNS only consider responses with |
1119 | * equivalent query section to the request. For mDNS this check doesn't make | |
1120 | * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT | |
1121 | * contain any questions in the Question Section". */ | |
1122 | if (t->scope->protocol != DNS_PROTOCOL_MDNS) { | |
1123 | r = dns_packet_is_reply_for(p, t->key); | |
1124 | if (r < 0) | |
1125 | goto fail; | |
1126 | if (r == 0) { | |
1127 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1128 | return; | |
1129 | } | |
547493c5 | 1130 | } |
29815b6c | 1131 | |
547493c5 DM |
1132 | /* Install the answer as answer to the transaction */ |
1133 | dns_answer_unref(t->answer); | |
1134 | t->answer = dns_answer_ref(p->answer); | |
1135 | t->answer_rcode = DNS_PACKET_RCODE(p); | |
919c2ae0 | 1136 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
105e1512 | 1137 | t->answer_authenticated = false; |
79e24931 | 1138 | |
eac7cda2 LP |
1139 | r = dns_transaction_fix_rcode(t); |
1140 | if (r < 0) | |
1141 | goto fail; | |
1142 | ||
51e399bc LP |
1143 | /* Block GC while starting requests for additional DNSSEC RRs */ |
1144 | t->block_gc++; | |
547973de | 1145 | r = dns_transaction_request_dnssec_keys(t); |
51e399bc LP |
1146 | t->block_gc--; |
1147 | ||
1148 | /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ | |
1149 | if (!dns_transaction_gc(t)) | |
1150 | return; | |
1151 | ||
1152 | /* Requesting additional keys might have resulted in | |
1153 | * this transaction to fail, since the auxiliary | |
1154 | * request failed for some reason. If so, we are not | |
1155 | * in pending state anymore, and we should exit | |
1156 | * quickly. */ | |
1157 | if (t->state != DNS_TRANSACTION_PENDING) | |
1158 | return; | |
7cc6ed7b LP |
1159 | if (r < 0) |
1160 | goto fail; | |
547973de LP |
1161 | if (r > 0) { |
1162 | /* There are DNSSEC transactions pending now. Update the state accordingly. */ | |
1163 | t->state = DNS_TRANSACTION_VALIDATING; | |
f535705a LP |
1164 | dns_transaction_close_connection(t); |
1165 | dns_transaction_stop_timeout(t); | |
547973de LP |
1166 | return; |
1167 | } | |
547493c5 | 1168 | } |
ec2c5e43 | 1169 | |
547973de | 1170 | dns_transaction_process_dnssec(t); |
7cc6ed7b LP |
1171 | return; |
1172 | ||
1173 | fail: | |
1174 | t->answer_errno = -r; | |
1175 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 LP |
1176 | } |
1177 | ||
c19ffd9f TG |
1178 | static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
1179 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1180 | DnsTransaction *t = userdata; | |
1181 | int r; | |
1182 | ||
1183 | assert(t); | |
1184 | assert(t->scope); | |
1185 | ||
1186 | r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); | |
7e1851e3 LP |
1187 | if (ERRNO_IS_DISCONNECT(-r)) { |
1188 | usec_t usec; | |
c19ffd9f | 1189 | |
7e1851e3 LP |
1190 | /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next |
1191 | * recvmsg(). Treat this like a lost packet. */ | |
1192 | ||
92ec902a | 1193 | log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); |
7e1851e3 | 1194 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
3da3cdd5 | 1195 | dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level); |
7e1851e3 | 1196 | |
d001e0a3 | 1197 | dns_transaction_retry(t, true); |
7e1851e3 LP |
1198 | return 0; |
1199 | } | |
1200 | if (r < 0) { | |
7cc6ed7b LP |
1201 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); |
1202 | t->answer_errno = -r; | |
7e1851e3 LP |
1203 | return 0; |
1204 | } | |
1205 | ||
1206 | r = dns_packet_validate_reply(p); | |
1207 | if (r < 0) { | |
1208 | log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); | |
1209 | return 0; | |
1210 | } | |
1211 | if (r == 0) { | |
e09f605e | 1212 | log_debug("Received inappropriate DNS packet as response, ignoring."); |
7e1851e3 LP |
1213 | return 0; |
1214 | } | |
1215 | ||
1216 | if (DNS_PACKET_ID(p) != t->id) { | |
e09f605e | 1217 | log_debug("Received packet with incorrect transaction ID, ignoring."); |
7e1851e3 LP |
1218 | return 0; |
1219 | } | |
c19ffd9f | 1220 | |
7e1851e3 | 1221 | dns_transaction_process_reply(t, p); |
c19ffd9f TG |
1222 | return 0; |
1223 | } | |
1224 | ||
49cce12d | 1225 | static int dns_transaction_emit_udp(DnsTransaction *t) { |
c19ffd9f TG |
1226 | int r; |
1227 | ||
1228 | assert(t); | |
c19ffd9f | 1229 | |
519ef046 | 1230 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { |
c19ffd9f | 1231 | |
519ef046 | 1232 | r = dns_transaction_pick_server(t); |
471d40d9 TG |
1233 | if (r < 0) |
1234 | return r; | |
c19ffd9f | 1235 | |
5d67a7ae | 1236 | if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP || DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) |
7d581a65 | 1237 | return -EAGAIN; /* Sorry, can't do UDP, try TCP! */ |
519ef046 | 1238 | |
92ec902a | 1239 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
1240 | return -EOPNOTSUPP; |
1241 | ||
519ef046 LP |
1242 | if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ |
1243 | int fd; | |
1244 | ||
1245 | dns_transaction_close_connection(t); | |
c19ffd9f | 1246 | |
519ef046 LP |
1247 | fd = dns_scope_socket_udp(t->scope, t->server, 53); |
1248 | if (fd < 0) | |
1249 | return fd; | |
1250 | ||
1251 | r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); | |
1252 | if (r < 0) { | |
1253 | safe_close(fd); | |
1254 | return r; | |
1255 | } | |
1256 | ||
aa4a9deb | 1257 | (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); |
519ef046 LP |
1258 | t->dns_udp_fd = fd; |
1259 | } | |
1260 | ||
274b8748 | 1261 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
1262 | if (r < 0) |
1263 | return r; | |
1264 | } else | |
1265 | dns_transaction_close_connection(t); | |
1266 | ||
1267 | r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); | |
471d40d9 TG |
1268 | if (r < 0) |
1269 | return r; | |
c19ffd9f | 1270 | |
519ef046 | 1271 | dns_transaction_reset_answer(t); |
be808ea0 | 1272 | |
471d40d9 | 1273 | return 0; |
c19ffd9f TG |
1274 | } |
1275 | ||
ec2c5e43 LP |
1276 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { |
1277 | DnsTransaction *t = userdata; | |
ec2c5e43 LP |
1278 | |
1279 | assert(s); | |
1280 | assert(t); | |
1281 | ||
ef7ce6df DM |
1282 | if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { |
1283 | /* Timeout reached? Increase the timeout for the server used */ | |
1284 | switch (t->scope->protocol) { | |
49cce12d | 1285 | |
ef7ce6df DM |
1286 | case DNS_PROTOCOL_DNS: |
1287 | assert(t->server); | |
3da3cdd5 | 1288 | dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level); |
ef7ce6df | 1289 | break; |
49cce12d | 1290 | |
ef7ce6df DM |
1291 | case DNS_PROTOCOL_LLMNR: |
1292 | case DNS_PROTOCOL_MDNS: | |
1293 | dns_scope_packet_lost(t->scope, usec - t->start_usec); | |
ef7ce6df | 1294 | break; |
49cce12d | 1295 | |
ef7ce6df DM |
1296 | default: |
1297 | assert_not_reached("Invalid DNS protocol."); | |
1298 | } | |
1299 | ||
1300 | if (t->initial_jitter_scheduled) | |
1301 | t->initial_jitter_elapsed = true; | |
be808ea0 TG |
1302 | } |
1303 | ||
423659ab LP |
1304 | log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); |
1305 | ||
d001e0a3 | 1306 | dns_transaction_retry(t, true); |
ec2c5e43 LP |
1307 | return 0; |
1308 | } | |
1309 | ||
9df3ba6c TG |
1310 | static usec_t transaction_get_resend_timeout(DnsTransaction *t) { |
1311 | assert(t); | |
1312 | assert(t->scope); | |
1313 | ||
1314 | switch (t->scope->protocol) { | |
49cce12d | 1315 | |
9df3ba6c | 1316 | case DNS_PROTOCOL_DNS: |
dc349f5f LP |
1317 | |
1318 | /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly | |
1319 | * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that | |
1320 | * needlessly. */ | |
1321 | if (t->stream) | |
1322 | return TRANSACTION_TCP_TIMEOUT_USEC; | |
1323 | ||
dbc4661a | 1324 | return DNS_TIMEOUT_USEC; |
49cce12d | 1325 | |
9df3ba6c | 1326 | case DNS_PROTOCOL_MDNS: |
11a27c2e | 1327 | assert(t->n_attempts > 0); |
53fda2bb DR |
1328 | if (t->probing) |
1329 | return MDNS_PROBING_INTERVAL_USEC; | |
1330 | else | |
1331 | return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; | |
49cce12d | 1332 | |
11a27c2e | 1333 | case DNS_PROTOCOL_LLMNR: |
9df3ba6c | 1334 | return t->scope->resend_timeout; |
49cce12d | 1335 | |
9df3ba6c TG |
1336 | default: |
1337 | assert_not_reached("Invalid DNS protocol."); | |
1338 | } | |
1339 | } | |
1340 | ||
c842ff24 | 1341 | static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { |
ec2c5e43 LP |
1342 | int r; |
1343 | ||
1344 | assert(t); | |
1345 | ||
f535705a | 1346 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 1347 | |
86b112a3 | 1348 | if (!dns_scope_network_good(t->scope)) { |
edbcc1fd LP |
1349 | dns_transaction_complete(t, DNS_TRANSACTION_NETWORK_DOWN); |
1350 | return 0; | |
1351 | } | |
1352 | ||
ec2c5e43 LP |
1353 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { |
1354 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1355 | return 0; | |
1356 | } | |
1357 | ||
cbe4216d | 1358 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { |
ec2c5e43 LP |
1359 | /* If we already tried via a stream, then we don't |
1360 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
1361 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1362 | return 0; | |
1363 | } | |
1364 | ||
1365 | t->n_attempts++; | |
9df3ba6c | 1366 | t->start_usec = ts; |
c61d2b44 LP |
1367 | |
1368 | dns_transaction_reset_answer(t); | |
c5b4f861 | 1369 | dns_transaction_flush_dnssec_transactions(t); |
ec2c5e43 | 1370 | |
0d2cd476 LP |
1371 | /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ |
1372 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
8e54f5d9 | 1373 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); |
0d2cd476 LP |
1374 | if (r < 0) |
1375 | return r; | |
1376 | if (r > 0) { | |
1377 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1378 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
931851e8 | 1379 | t->answer_authenticated = true; |
0d2cd476 LP |
1380 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1381 | return 0; | |
1382 | } | |
b2b796b8 | 1383 | |
1c02e7ba | 1384 | if (dns_name_is_root(dns_resource_key_name(t->key)) && |
b2b796b8 LP |
1385 | t->key->type == DNS_TYPE_DS) { |
1386 | ||
1387 | /* Hmm, this is a request for the root DS? A | |
1388 | * DS RR doesn't exist in the root zone, and | |
1389 | * if our trust anchor didn't know it either, | |
1390 | * this means we cannot do any DNSSEC logic | |
1391 | * anymore. */ | |
1392 | ||
1ed8c0fb | 1393 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
b2b796b8 LP |
1394 | /* We are in downgrade mode. In this |
1395 | * case, synthesize an unsigned empty | |
1396 | * response, so that the any lookup | |
1397 | * depending on this one can continue | |
1398 | * assuming there was no DS, and hence | |
1399 | * the root zone was unsigned. */ | |
1400 | ||
1401 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1402 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
1403 | t->answer_authenticated = false; | |
1404 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
1405 | } else | |
1406 | /* If we are not in downgrade mode, | |
1407 | * then fail the lookup, because we | |
1408 | * cannot reasonably answer it. There | |
1409 | * might be DS RRs, but we don't know | |
1410 | * them, and the DNS server won't tell | |
1411 | * them to us (and even if it would, | |
202b76ae | 1412 | * we couldn't validate and trust them. */ |
b2b796b8 LP |
1413 | dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); |
1414 | ||
1415 | return 0; | |
1416 | } | |
0d2cd476 LP |
1417 | } |
1418 | ||
1419 | /* Check the zone, but only if this transaction is not used | |
d746bb3e | 1420 | * for probing or verifying a zone item. */ |
547973de | 1421 | if (set_isempty(t->notify_zone_items)) { |
d746bb3e | 1422 | |
97ebebbc | 1423 | r = dns_zone_lookup(&t->scope->zone, t->key, dns_scope_ifindex(t->scope), &t->answer, NULL, NULL); |
d746bb3e LP |
1424 | if (r < 0) |
1425 | return r; | |
1426 | if (r > 0) { | |
ae6a4bbf | 1427 | t->answer_rcode = DNS_RCODE_SUCCESS; |
c3bc53e6 | 1428 | t->answer_source = DNS_TRANSACTION_ZONE; |
931851e8 | 1429 | t->answer_authenticated = true; |
d746bb3e LP |
1430 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1431 | return 0; | |
1432 | } | |
1433 | } | |
1434 | ||
4d926a69 LP |
1435 | /* Check the cache, but only if this transaction is not used |
1436 | * for probing or verifying a zone item. */ | |
547973de | 1437 | if (set_isempty(t->notify_zone_items)) { |
2c27fbca | 1438 | |
4d926a69 LP |
1439 | /* Before trying the cache, let's make sure we figured out a |
1440 | * server to use. Should this cause a change of server this | |
1441 | * might flush the cache. */ | |
5cdb8930 | 1442 | (void) dns_scope_get_dns_server(t->scope); |
2c27fbca | 1443 | |
4d926a69 LP |
1444 | /* Let's then prune all outdated entries */ |
1445 | dns_cache_prune(&t->scope->cache); | |
1446 | ||
17c8de63 | 1447 | r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); |
4d926a69 LP |
1448 | if (r < 0) |
1449 | return r; | |
1450 | if (r > 0) { | |
c3bc53e6 | 1451 | t->answer_source = DNS_TRANSACTION_CACHE; |
ae6a4bbf | 1452 | if (t->answer_rcode == DNS_RCODE_SUCCESS) |
4d926a69 LP |
1453 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1454 | else | |
3bbdc31d | 1455 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
4d926a69 LP |
1456 | return 0; |
1457 | } | |
ec2c5e43 LP |
1458 | } |
1459 | ||
1effe965 DM |
1460 | return 1; |
1461 | } | |
1462 | ||
0afa57e2 DM |
1463 | static int dns_transaction_make_packet_mdns(DnsTransaction *t) { |
1464 | ||
1465 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
7778dfff | 1466 | bool add_known_answers = false; |
0afa57e2 | 1467 | DnsTransaction *other; |
0d5ee47d DR |
1468 | Iterator i; |
1469 | DnsResourceKey *tkey; | |
1470 | _cleanup_set_free_ Set *keys = NULL; | |
0afa57e2 | 1471 | unsigned qdcount; |
0d5ee47d | 1472 | unsigned nscount = 0; |
0afa57e2 DM |
1473 | usec_t ts; |
1474 | int r; | |
1475 | ||
1476 | assert(t); | |
1477 | assert(t->scope->protocol == DNS_PROTOCOL_MDNS); | |
1478 | ||
e5abebab | 1479 | /* Discard any previously prepared packet, so we can start over and coalesce again */ |
0afa57e2 DM |
1480 | t->sent = dns_packet_unref(t->sent); |
1481 | ||
1482 | r = dns_packet_new_query(&p, t->scope->protocol, 0, false); | |
1483 | if (r < 0) | |
1484 | return r; | |
1485 | ||
58ab31d5 | 1486 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1487 | if (r < 0) |
1488 | return r; | |
1489 | ||
1490 | qdcount = 1; | |
1491 | ||
7778dfff DM |
1492 | if (dns_key_is_shared(t->key)) |
1493 | add_known_answers = true; | |
1494 | ||
0d5ee47d DR |
1495 | if (t->key->type == DNS_TYPE_ANY) { |
1496 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1497 | if (r < 0) | |
1498 | return r; | |
1499 | ||
1500 | r = set_put(keys, t->key); | |
1501 | if (r < 0) | |
1502 | return r; | |
1503 | } | |
1504 | ||
0afa57e2 DM |
1505 | /* |
1506 | * For mDNS, we want to coalesce as many open queries in pending transactions into one single | |
1507 | * query packet on the wire as possible. To achieve that, we iterate through all pending transactions | |
1508 | * in our current scope, and see whether their timing contraints allow them to be sent. | |
1509 | */ | |
1510 | ||
1511 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
1512 | ||
1513 | LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { | |
1514 | ||
1515 | /* Skip ourselves */ | |
1516 | if (other == t) | |
1517 | continue; | |
1518 | ||
1519 | if (other->state != DNS_TRANSACTION_PENDING) | |
1520 | continue; | |
1521 | ||
1522 | if (other->next_attempt_after > ts) | |
1523 | continue; | |
1524 | ||
1525 | if (qdcount >= UINT16_MAX) | |
1526 | break; | |
1527 | ||
58ab31d5 | 1528 | r = dns_packet_append_key(p, other->key, 0, NULL); |
0afa57e2 DM |
1529 | |
1530 | /* | |
1531 | * If we can't stuff more questions into the packet, just give up. | |
1532 | * One of the 'other' transactions will fire later and take care of the rest. | |
1533 | */ | |
1534 | if (r == -EMSGSIZE) | |
1535 | break; | |
1536 | ||
1537 | if (r < 0) | |
1538 | return r; | |
1539 | ||
c842ff24 | 1540 | r = dns_transaction_prepare(other, ts); |
0afa57e2 DM |
1541 | if (r <= 0) |
1542 | continue; | |
1543 | ||
1544 | ts += transaction_get_resend_timeout(other); | |
1545 | ||
1546 | r = sd_event_add_time( | |
1547 | other->scope->manager->event, | |
1548 | &other->timeout_event_source, | |
1549 | clock_boottime_or_monotonic(), | |
1550 | ts, 0, | |
1551 | on_transaction_timeout, other); | |
1552 | if (r < 0) | |
1553 | return r; | |
1554 | ||
ff537038 | 1555 | (void) sd_event_source_set_description(other->timeout_event_source, "dns-transaction-timeout"); |
aa4a9deb | 1556 | |
0afa57e2 DM |
1557 | other->state = DNS_TRANSACTION_PENDING; |
1558 | other->next_attempt_after = ts; | |
1559 | ||
313cefa1 | 1560 | qdcount++; |
7778dfff DM |
1561 | |
1562 | if (dns_key_is_shared(other->key)) | |
1563 | add_known_answers = true; | |
0d5ee47d DR |
1564 | |
1565 | if (other->key->type == DNS_TYPE_ANY) { | |
1566 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1567 | if (r < 0) | |
1568 | return r; | |
1569 | ||
1570 | r = set_put(keys, other->key); | |
1571 | if (r < 0) | |
1572 | return r; | |
1573 | } | |
0afa57e2 DM |
1574 | } |
1575 | ||
1576 | DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); | |
0afa57e2 | 1577 | |
7778dfff DM |
1578 | /* Append known answer section if we're asking for any shared record */ |
1579 | if (add_known_answers) { | |
1580 | r = dns_cache_export_shared_to_packet(&t->scope->cache, p); | |
1581 | if (r < 0) | |
1582 | return r; | |
1583 | } | |
1584 | ||
0d5ee47d DR |
1585 | SET_FOREACH(tkey, keys, i) { |
1586 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; | |
1587 | bool tentative; | |
1588 | ||
1589 | r = dns_zone_lookup(&t->scope->zone, tkey, t->scope->link->ifindex, &answer, NULL, &tentative); | |
1590 | if (r < 0) | |
1591 | return r; | |
1592 | ||
1593 | r = dns_packet_append_answer(p, answer); | |
1594 | if (r < 0) | |
1595 | return r; | |
1596 | ||
1597 | nscount += dns_answer_size(answer); | |
1598 | } | |
1599 | DNS_PACKET_HEADER(p)->nscount = htobe16(nscount); | |
1600 | ||
1cc6c93a | 1601 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1602 | |
1603 | return 0; | |
1604 | } | |
1605 | ||
1606 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
1607 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1608 | int r; | |
1609 | ||
1610 | assert(t); | |
1611 | ||
1612 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) | |
1613 | return dns_transaction_make_packet_mdns(t); | |
1614 | ||
1615 | if (t->sent) | |
1616 | return 0; | |
1617 | ||
b652d4a2 | 1618 | r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); |
0afa57e2 DM |
1619 | if (r < 0) |
1620 | return r; | |
1621 | ||
58ab31d5 | 1622 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1623 | if (r < 0) |
1624 | return r; | |
1625 | ||
1626 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
1627 | DNS_PACKET_HEADER(p)->id = t->id; | |
1628 | ||
1cc6c93a | 1629 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1630 | |
1631 | return 0; | |
1632 | } | |
1633 | ||
1effe965 DM |
1634 | int dns_transaction_go(DnsTransaction *t) { |
1635 | usec_t ts; | |
1636 | int r; | |
202b76ae | 1637 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
1effe965 DM |
1638 | |
1639 | assert(t); | |
1640 | ||
5278bbfe LP |
1641 | /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished |
1642 | * now. */ | |
1643 | ||
1effe965 | 1644 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
547973de | 1645 | |
c842ff24 | 1646 | r = dns_transaction_prepare(t, ts); |
1effe965 DM |
1647 | if (r <= 0) |
1648 | return r; | |
1649 | ||
202b76ae | 1650 | log_debug("Transaction %" PRIu16 " for <%s> scope %s on %s/%s.", |
a5784c49 | 1651 | t->id, |
202b76ae | 1652 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
a5784c49 LP |
1653 | dns_protocol_to_string(t->scope->protocol), |
1654 | t->scope->link ? t->scope->link->name : "*", | |
202b76ae | 1655 | af_to_name_short(t->scope->family)); |
1effe965 | 1656 | |
ef7ce6df | 1657 | if (!t->initial_jitter_scheduled && |
3742095b | 1658 | IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
ea12bcc7 | 1659 | usec_t jitter, accuracy; |
6e068472 LP |
1660 | |
1661 | /* RFC 4795 Section 2.7 suggests all queries should be | |
1662 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
1663 | ||
ef7ce6df | 1664 | t->initial_jitter_scheduled = true; |
6e068472 LP |
1665 | |
1666 | random_bytes(&jitter, sizeof(jitter)); | |
ea12bcc7 DM |
1667 | |
1668 | switch (t->scope->protocol) { | |
519ef046 | 1669 | |
ea12bcc7 DM |
1670 | case DNS_PROTOCOL_LLMNR: |
1671 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
1672 | accuracy = LLMNR_JITTER_INTERVAL_USEC; | |
1673 | break; | |
519ef046 | 1674 | |
ea12bcc7 DM |
1675 | case DNS_PROTOCOL_MDNS: |
1676 | jitter %= MDNS_JITTER_RANGE_USEC; | |
1677 | jitter += MDNS_JITTER_MIN_USEC; | |
1678 | accuracy = MDNS_JITTER_RANGE_USEC; | |
1679 | break; | |
1680 | default: | |
1681 | assert_not_reached("bad protocol"); | |
1682 | } | |
6e068472 LP |
1683 | |
1684 | r = sd_event_add_time( | |
1685 | t->scope->manager->event, | |
1686 | &t->timeout_event_source, | |
1687 | clock_boottime_or_monotonic(), | |
ea12bcc7 | 1688 | ts + jitter, accuracy, |
6e068472 LP |
1689 | on_transaction_timeout, t); |
1690 | if (r < 0) | |
1691 | return r; | |
1692 | ||
aa4a9deb LP |
1693 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1694 | ||
6e068472 | 1695 | t->n_attempts = 0; |
a9da14e1 | 1696 | t->next_attempt_after = ts; |
6e068472 LP |
1697 | t->state = DNS_TRANSACTION_PENDING; |
1698 | ||
ea12bcc7 | 1699 | log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); |
6e068472 LP |
1700 | return 0; |
1701 | } | |
1702 | ||
ec2c5e43 LP |
1703 | /* Otherwise, we need to ask the network */ |
1704 | r = dns_transaction_make_packet(t); | |
ec2c5e43 LP |
1705 | if (r < 0) |
1706 | return r; | |
1707 | ||
1708 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
1c02e7ba ZJS |
1709 | (dns_name_endswith(dns_resource_key_name(t->key), "in-addr.arpa") > 0 || |
1710 | dns_name_endswith(dns_resource_key_name(t->key), "ip6.arpa") > 0)) { | |
ec2c5e43 LP |
1711 | |
1712 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
1713 | * always be made via TCP on LLMNR */ | |
98767d75 | 1714 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1715 | } else { |
be808ea0 TG |
1716 | /* Try via UDP, and if that fails due to large size or lack of |
1717 | * support try via TCP */ | |
49cce12d | 1718 | r = dns_transaction_emit_udp(t); |
29ab0552 LP |
1719 | if (r == -EMSGSIZE) |
1720 | log_debug("Sending query via TCP since it is too large."); | |
dc349f5f | 1721 | else if (r == -EAGAIN) |
5d67a7ae | 1722 | log_debug("Sending query via TCP since UDP isn't supported."); |
4c701096 | 1723 | if (IN_SET(r, -EMSGSIZE, -EAGAIN)) |
98767d75 | 1724 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1725 | } |
be808ea0 | 1726 | |
ec2c5e43 LP |
1727 | if (r == -ESRCH) { |
1728 | /* No servers to send this to? */ | |
1729 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1730 | return 0; | |
91adc4db LP |
1731 | } |
1732 | if (r == -EOPNOTSUPP) { | |
1733 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1734 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1735 | return 0; | |
1736 | } | |
0791110f | 1737 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(-r)) { |
e94968ba | 1738 | /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot |
0791110f LP |
1739 | * answer this request with this protocol. */ |
1740 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
1741 | return 0; | |
1742 | } | |
91adc4db | 1743 | if (r < 0) { |
7cc6ed7b LP |
1744 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1745 | return r; | |
13b551ac | 1746 | |
ec2c5e43 | 1747 | /* Couldn't send? Try immediately again, with a new server */ |
519ef046 | 1748 | dns_scope_next_dns_server(t->scope); |
ec2c5e43 LP |
1749 | |
1750 | return dns_transaction_go(t); | |
1751 | } | |
1752 | ||
a9da14e1 DM |
1753 | ts += transaction_get_resend_timeout(t); |
1754 | ||
9a015429 LP |
1755 | r = sd_event_add_time( |
1756 | t->scope->manager->event, | |
1757 | &t->timeout_event_source, | |
1758 | clock_boottime_or_monotonic(), | |
a9da14e1 | 1759 | ts, 0, |
9a015429 | 1760 | on_transaction_timeout, t); |
ec2c5e43 LP |
1761 | if (r < 0) |
1762 | return r; | |
1763 | ||
aa4a9deb LP |
1764 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1765 | ||
ec2c5e43 | 1766 | t->state = DNS_TRANSACTION_PENDING; |
a9da14e1 DM |
1767 | t->next_attempt_after = ts; |
1768 | ||
ec2c5e43 LP |
1769 | return 1; |
1770 | } | |
1771 | ||
f2992dc1 LP |
1772 | static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { |
1773 | DnsTransaction *n; | |
1774 | Iterator i; | |
1775 | int r; | |
1776 | ||
1777 | assert(t); | |
1778 | assert(aux); | |
1779 | ||
1780 | /* Try to find cyclic dependencies between transaction objects */ | |
1781 | ||
1782 | if (t == aux) | |
1783 | return 1; | |
1784 | ||
3eb6aa00 | 1785 | SET_FOREACH(n, aux->dnssec_transactions, i) { |
f2992dc1 LP |
1786 | r = dns_transaction_find_cyclic(t, n); |
1787 | if (r != 0) | |
1788 | return r; | |
1789 | } | |
1790 | ||
3eb6aa00 | 1791 | return 0; |
f2992dc1 LP |
1792 | } |
1793 | ||
547973de LP |
1794 | static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { |
1795 | DnsTransaction *aux; | |
1796 | int r; | |
1797 | ||
1798 | assert(t); | |
1799 | assert(ret); | |
1800 | assert(key); | |
1801 | ||
1802 | aux = dns_scope_find_transaction(t->scope, key, true); | |
1803 | if (!aux) { | |
1804 | r = dns_transaction_new(&aux, t->scope, key); | |
1805 | if (r < 0) | |
1806 | return r; | |
1807 | } else { | |
1808 | if (set_contains(t->dnssec_transactions, aux)) { | |
1809 | *ret = aux; | |
1810 | return 0; | |
1811 | } | |
f2992dc1 LP |
1812 | |
1813 | r = dns_transaction_find_cyclic(t, aux); | |
1814 | if (r < 0) | |
1815 | return r; | |
1816 | if (r > 0) { | |
202b76ae ZJS |
1817 | char s[DNS_RESOURCE_KEY_STRING_MAX], saux[DNS_RESOURCE_KEY_STRING_MAX]; |
1818 | ||
baaa35ad ZJS |
1819 | return log_debug_errno(SYNTHETIC_ERRNO(ELOOP), |
1820 | "Potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", | |
1821 | aux->id, | |
1822 | dns_resource_key_to_string(t->key, s, sizeof s), | |
1823 | t->id, | |
1824 | dns_resource_key_to_string(aux->key, saux, sizeof saux)); | |
f2992dc1 | 1825 | } |
547973de LP |
1826 | } |
1827 | ||
1828 | r = set_ensure_allocated(&t->dnssec_transactions, NULL); | |
1829 | if (r < 0) | |
1830 | goto gc; | |
1831 | ||
1832 | r = set_ensure_allocated(&aux->notify_transactions, NULL); | |
1833 | if (r < 0) | |
35aa04e9 LP |
1834 | goto gc; |
1835 | ||
1836 | r = set_ensure_allocated(&aux->notify_transactions_done, NULL); | |
1837 | if (r < 0) | |
547973de LP |
1838 | goto gc; |
1839 | ||
1840 | r = set_put(t->dnssec_transactions, aux); | |
1841 | if (r < 0) | |
1842 | goto gc; | |
1843 | ||
1844 | r = set_put(aux->notify_transactions, t); | |
1845 | if (r < 0) { | |
1846 | (void) set_remove(t->dnssec_transactions, aux); | |
1847 | goto gc; | |
1848 | } | |
1849 | ||
1850 | *ret = aux; | |
1851 | return 1; | |
1852 | ||
1853 | gc: | |
1854 | dns_transaction_gc(aux); | |
1855 | return r; | |
1856 | } | |
1857 | ||
1858 | static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { | |
1859 | _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; | |
1860 | DnsTransaction *aux; | |
1861 | int r; | |
1862 | ||
1863 | assert(t); | |
1864 | assert(key); | |
1865 | ||
1866 | /* Try to get the data from the trust anchor */ | |
8e54f5d9 | 1867 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); |
547973de LP |
1868 | if (r < 0) |
1869 | return r; | |
1870 | if (r > 0) { | |
1871 | r = dns_answer_extend(&t->validated_keys, a); | |
1872 | if (r < 0) | |
1873 | return r; | |
1874 | ||
1875 | return 0; | |
1876 | } | |
1877 | ||
1878 | /* This didn't work, ask for it via the network/cache then. */ | |
1879 | r = dns_transaction_add_dnssec_transaction(t, key, &aux); | |
f2992dc1 LP |
1880 | if (r == -ELOOP) /* This would result in a cyclic dependency */ |
1881 | return 0; | |
547973de LP |
1882 | if (r < 0) |
1883 | return r; | |
1884 | ||
1885 | if (aux->state == DNS_TRANSACTION_NULL) { | |
1886 | r = dns_transaction_go(aux); | |
1887 | if (r < 0) | |
1888 | return r; | |
1889 | } | |
1890 | ||
f2992dc1 | 1891 | return 1; |
547973de LP |
1892 | } |
1893 | ||
8a516214 LP |
1894 | static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { |
1895 | int r; | |
1896 | ||
1897 | assert(t); | |
1898 | ||
c629ff58 | 1899 | /* Check whether the specified name is in the NTA |
8a516214 LP |
1900 | * database, either in the global one, or the link-local |
1901 | * one. */ | |
1902 | ||
1903 | r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); | |
1904 | if (r != 0) | |
1905 | return r; | |
1906 | ||
1907 | if (!t->scope->link) | |
1908 | return 0; | |
1909 | ||
1910 | return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); | |
1911 | } | |
1912 | ||
105e1512 LP |
1913 | static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { |
1914 | int r; | |
1915 | ||
1916 | assert(t); | |
1917 | ||
1918 | /* Checks whether the answer is negative, and lacks NSEC/NSEC3 | |
1919 | * RRs to prove it */ | |
1920 | ||
1921 | r = dns_transaction_has_positive_answer(t, NULL); | |
1922 | if (r < 0) | |
1923 | return r; | |
1924 | if (r > 0) | |
1925 | return false; | |
1926 | ||
8e54f5d9 LP |
1927 | /* Is this key explicitly listed as a negative trust anchor? |
1928 | * If so, it's nothing we need to care about */ | |
1c02e7ba | 1929 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
1930 | if (r < 0) |
1931 | return r; | |
1932 | if (r > 0) | |
1933 | return false; | |
1934 | ||
105e1512 LP |
1935 | /* The answer does not contain any RRs that match to the |
1936 | * question. If so, let's see if there are any NSEC/NSEC3 RRs | |
1937 | * included. If not, the answer is unsigned. */ | |
1938 | ||
1939 | r = dns_answer_contains_nsec_or_nsec3(t->answer); | |
1940 | if (r < 0) | |
1941 | return r; | |
1942 | if (r > 0) | |
1943 | return false; | |
1944 | ||
1945 | return true; | |
1946 | } | |
1947 | ||
1948 | static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { | |
1949 | int r; | |
1950 | ||
1951 | assert(t); | |
1952 | assert(rr); | |
1953 | ||
1954 | /* Check if the specified RR is the "primary" response, | |
1955 | * i.e. either matches the question precisely or is a | |
4cb94977 | 1956 | * CNAME/DNAME for it. */ |
105e1512 LP |
1957 | |
1958 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1959 | if (r != 0) | |
1960 | return r; | |
1961 | ||
4cb94977 | 1962 | return dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); |
105e1512 LP |
1963 | } |
1964 | ||
92ec902a LP |
1965 | static bool dns_transaction_dnssec_supported(DnsTransaction *t) { |
1966 | assert(t); | |
1967 | ||
1968 | /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon | |
1969 | * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ | |
1970 | ||
1971 | if (t->scope->protocol != DNS_PROTOCOL_DNS) | |
1972 | return false; | |
1973 | ||
1974 | /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well | |
1975 | * be supported, hence return true. */ | |
1976 | if (!t->server) | |
1977 | return true; | |
1978 | ||
d001e0a3 LP |
1979 | /* Note that we do not check the feature level actually used for the transaction but instead the feature level |
1980 | * the server is known to support currently, as the transaction feature level might be lower than what the | |
1981 | * server actually supports, since we might have downgraded this transaction's feature level because we got a | |
1982 | * SERVFAIL earlier and wanted to check whether downgrading fixes it. */ | |
92ec902a LP |
1983 | |
1984 | return dns_server_dnssec_supported(t->server); | |
1985 | } | |
1986 | ||
1987 | static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { | |
1988 | DnsTransaction *dt; | |
1989 | Iterator i; | |
1990 | ||
1991 | assert(t); | |
1992 | ||
1993 | /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ | |
1994 | ||
1995 | if (!dns_transaction_dnssec_supported(t)) | |
1996 | return false; | |
1997 | ||
1998 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
1999 | if (!dns_transaction_dnssec_supported(dt)) | |
2000 | return false; | |
2001 | ||
2002 | return true; | |
2003 | } | |
2004 | ||
547973de LP |
2005 | int dns_transaction_request_dnssec_keys(DnsTransaction *t) { |
2006 | DnsResourceRecord *rr; | |
105e1512 | 2007 | |
547973de LP |
2008 | int r; |
2009 | ||
2010 | assert(t); | |
2011 | ||
105e1512 LP |
2012 | /* |
2013 | * Retrieve all auxiliary RRs for the answer we got, so that | |
2014 | * we can verify signatures or prove that RRs are rightfully | |
2015 | * unsigned. Specifically: | |
2016 | * | |
2017 | * - For RRSIG we get the matching DNSKEY | |
2018 | * - For DNSKEY we get the matching DS | |
2019 | * - For unsigned SOA/NS we get the matching DS | |
b63fca62 | 2020 | * - For unsigned CNAME/DNAME/DS we get the parent SOA RR |
105e1512 | 2021 | * - For other unsigned RRs we get the matching SOA RR |
4bbc06cc LP |
2022 | * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR |
2023 | * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR | |
105e1512 LP |
2024 | * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR |
2025 | */ | |
2026 | ||
b652d4a2 | 2027 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de | 2028 | return 0; |
92ec902a LP |
2029 | if (t->answer_source != DNS_TRANSACTION_NETWORK) |
2030 | return 0; /* We only need to validate stuff from the network */ | |
2031 | if (!dns_transaction_dnssec_supported(t)) | |
2032 | return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */ | |
b652d4a2 | 2033 | |
547973de LP |
2034 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2035 | ||
105e1512 LP |
2036 | if (dns_type_is_pseudo(rr->key->type)) |
2037 | continue; | |
2038 | ||
8e54f5d9 | 2039 | /* If this RR is in the negative trust anchor, we don't need to validate it. */ |
1c02e7ba | 2040 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2041 | if (r < 0) |
2042 | return r; | |
2043 | if (r > 0) | |
2044 | continue; | |
2045 | ||
547973de LP |
2046 | switch (rr->key->type) { |
2047 | ||
2048 | case DNS_TYPE_RRSIG: { | |
2049 | /* For each RRSIG we request the matching DNSKEY */ | |
2050 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; | |
2051 | ||
2052 | /* If this RRSIG is about a DNSKEY RR and the | |
2053 | * signer is the same as the owner, then we | |
2054 | * already have the DNSKEY, and we don't have | |
2055 | * to look for more. */ | |
2056 | if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { | |
1c02e7ba | 2057 | r = dns_name_equal(rr->rrsig.signer, dns_resource_key_name(rr->key)); |
547973de LP |
2058 | if (r < 0) |
2059 | return r; | |
2060 | if (r > 0) | |
2061 | continue; | |
2062 | } | |
2063 | ||
105e1512 LP |
2064 | /* If the signer is not a parent of our |
2065 | * original query, then this is about an | |
2066 | * auxiliary RRset, but not anything we asked | |
2067 | * for. In this case we aren't interested, | |
2068 | * because we don't want to request additional | |
2069 | * RRs for stuff we didn't really ask for, and | |
2070 | * also to avoid request loops, where | |
2071 | * additional RRs from one transaction result | |
2072 | * in another transaction whose additonal RRs | |
2073 | * point back to the original transaction, and | |
2074 | * we deadlock. */ | |
1c02e7ba | 2075 | r = dns_name_endswith(dns_resource_key_name(t->key), rr->rrsig.signer); |
547973de LP |
2076 | if (r < 0) |
2077 | return r; | |
2078 | if (r == 0) | |
2079 | continue; | |
2080 | ||
2081 | dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); | |
2082 | if (!dnskey) | |
2083 | return -ENOMEM; | |
2084 | ||
1c02e7ba ZJS |
2085 | log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", |
2086 | t->id, dns_resource_key_name(rr->key), rr->rrsig.key_tag); | |
547973de LP |
2087 | r = dns_transaction_request_dnssec_rr(t, dnskey); |
2088 | if (r < 0) | |
2089 | return r; | |
2090 | break; | |
2091 | } | |
2092 | ||
2093 | case DNS_TYPE_DNSKEY: { | |
2094 | /* For each DNSKEY we request the matching DS */ | |
2095 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2096 | ||
105e1512 LP |
2097 | /* If the DNSKEY we are looking at is not for |
2098 | * zone we are interested in, nor any of its | |
2099 | * parents, we aren't interested, and don't | |
2100 | * request it. After all, we don't want to end | |
2101 | * up in request loops, and want to keep | |
2102 | * additional traffic down. */ | |
2103 | ||
1c02e7ba | 2104 | r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2105 | if (r < 0) |
2106 | return r; | |
2107 | if (r == 0) | |
2108 | continue; | |
2109 | ||
1c02e7ba | 2110 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
547973de LP |
2111 | if (!ds) |
2112 | return -ENOMEM; | |
2113 | ||
1c02e7ba ZJS |
2114 | log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", |
2115 | t->id, dns_resource_key_name(rr->key), dnssec_keytag(rr, false)); | |
105e1512 LP |
2116 | r = dns_transaction_request_dnssec_rr(t, ds); |
2117 | if (r < 0) | |
2118 | return r; | |
547973de | 2119 | |
105e1512 LP |
2120 | break; |
2121 | } | |
2122 | ||
105e1512 LP |
2123 | case DNS_TYPE_SOA: |
2124 | case DNS_TYPE_NS: { | |
2125 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2126 | ||
2127 | /* For an unsigned SOA or NS, try to acquire | |
2128 | * the matching DS RR, as we are at a zone cut | |
2129 | * then, and whether a DS exists tells us | |
2130 | * whether the zone is signed. Do so only if | |
2131 | * this RR matches our original question, | |
2132 | * however. */ | |
2133 | ||
2134 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
2135 | if (r < 0) | |
2136 | return r; | |
6993d264 LP |
2137 | if (r == 0) { |
2138 | /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is | |
2139 | * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry? | |
2140 | * If so, we need to validate it, too. */ | |
2141 | ||
2142 | r = dns_answer_match_key(t->answer, t->key, NULL); | |
2143 | if (r < 0) | |
2144 | return r; | |
2145 | if (r > 0) /* positive reply, we won't need the SOA and hence don't need to validate | |
2146 | * it. */ | |
2147 | continue; | |
2148 | } | |
105e1512 LP |
2149 | |
2150 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2151 | if (r < 0) | |
2152 | return r; | |
2153 | if (r > 0) | |
2154 | continue; | |
2155 | ||
1c02e7ba | 2156 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
105e1512 LP |
2157 | if (!ds) |
2158 | return -ENOMEM; | |
2159 | ||
1c02e7ba ZJS |
2160 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", |
2161 | t->id, dns_resource_key_name(rr->key)); | |
547973de LP |
2162 | r = dns_transaction_request_dnssec_rr(t, ds); |
2163 | if (r < 0) | |
2164 | return r; | |
2165 | ||
2166 | break; | |
105e1512 LP |
2167 | } |
2168 | ||
b63fca62 | 2169 | case DNS_TYPE_DS: |
105e1512 LP |
2170 | case DNS_TYPE_CNAME: |
2171 | case DNS_TYPE_DNAME: { | |
2172 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2173 | const char *name; | |
2174 | ||
2175 | /* CNAMEs and DNAMEs cannot be located at a | |
2176 | * zone apex, hence ask for the parent SOA for | |
2177 | * unsigned CNAME/DNAME RRs, maybe that's the | |
2178 | * apex. But do all that only if this is | |
2179 | * actually a response to our original | |
b63fca62 LP |
2180 | * question. |
2181 | * | |
2182 | * Similar for DS RRs, which are signed when | |
2183 | * the parent SOA is signed. */ | |
105e1512 LP |
2184 | |
2185 | r = dns_transaction_is_primary_response(t, rr); | |
2186 | if (r < 0) | |
2187 | return r; | |
2188 | if (r == 0) | |
2189 | continue; | |
2190 | ||
2191 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2192 | if (r < 0) | |
2193 | return r; | |
2194 | if (r > 0) | |
2195 | continue; | |
2196 | ||
43e6779a LP |
2197 | r = dns_answer_has_dname_for_cname(t->answer, rr); |
2198 | if (r < 0) | |
2199 | return r; | |
2200 | if (r > 0) | |
2201 | continue; | |
2202 | ||
1c02e7ba | 2203 | name = dns_resource_key_name(rr->key); |
105e1512 LP |
2204 | r = dns_name_parent(&name); |
2205 | if (r < 0) | |
2206 | return r; | |
2207 | if (r == 0) | |
2208 | continue; | |
2209 | ||
2210 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); | |
2211 | if (!soa) | |
2212 | return -ENOMEM; | |
2213 | ||
1c02e7ba ZJS |
2214 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", |
2215 | t->id, dns_resource_key_name(rr->key)); | |
105e1512 LP |
2216 | r = dns_transaction_request_dnssec_rr(t, soa); |
2217 | if (r < 0) | |
2218 | return r; | |
2219 | ||
2220 | break; | |
2221 | } | |
2222 | ||
2223 | default: { | |
2224 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2225 | ||
b63fca62 LP |
2226 | /* For other unsigned RRsets (including |
2227 | * NSEC/NSEC3!), look for proof the zone is | |
2228 | * unsigned, by requesting the SOA RR of the | |
2229 | * zone. However, do so only if they are | |
2230 | * directly relevant to our original | |
105e1512 LP |
2231 | * question. */ |
2232 | ||
2233 | r = dns_transaction_is_primary_response(t, rr); | |
2234 | if (r < 0) | |
2235 | return r; | |
2236 | if (r == 0) | |
2237 | continue; | |
2238 | ||
2239 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2240 | if (r < 0) | |
2241 | return r; | |
2242 | if (r > 0) | |
2243 | continue; | |
2244 | ||
1c02e7ba | 2245 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, dns_resource_key_name(rr->key)); |
105e1512 LP |
2246 | if (!soa) |
2247 | return -ENOMEM; | |
2248 | ||
1c02e7ba ZJS |
2249 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", |
2250 | t->id, dns_resource_key_name(rr->key), dns_resource_record_to_string(rr)); | |
105e1512 LP |
2251 | r = dns_transaction_request_dnssec_rr(t, soa); |
2252 | if (r < 0) | |
2253 | return r; | |
2254 | break; | |
547973de LP |
2255 | }} |
2256 | } | |
2257 | ||
105e1512 LP |
2258 | /* Above, we requested everything necessary to validate what |
2259 | * we got. Now, let's request what we need to validate what we | |
2260 | * didn't get... */ | |
2261 | ||
2262 | r = dns_transaction_has_unsigned_negative_answer(t); | |
2263 | if (r < 0) | |
2264 | return r; | |
2265 | if (r > 0) { | |
2266 | const char *name; | |
4bbc06cc | 2267 | uint16_t type = 0; |
105e1512 | 2268 | |
1c02e7ba | 2269 | name = dns_resource_key_name(t->key); |
105e1512 | 2270 | |
4bbc06cc LP |
2271 | /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this |
2272 | * could also be used as indication that we are not at a zone apex, but in real world setups there are | |
2273 | * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even | |
2274 | * though they have further children. If this was a DS request, then it's signed when the parent zone | |
2275 | * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR, | |
2276 | * to see if that is signed. */ | |
105e1512 | 2277 | |
4bbc06cc | 2278 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2279 | r = dns_name_parent(&name); |
4bbc06cc LP |
2280 | if (r > 0) { |
2281 | type = DNS_TYPE_SOA; | |
2282 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty DS response).", | |
1c02e7ba | 2283 | t->id, dns_resource_key_name(t->key)); |
4bbc06cc | 2284 | } else |
105e1512 | 2285 | name = NULL; |
4bbc06cc LP |
2286 | |
2287 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) { | |
2288 | ||
2289 | type = DNS_TYPE_DS; | |
2290 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS response).", | |
2291 | t->id, dns_resource_key_name(t->key)); | |
2292 | ||
2293 | } else { | |
2294 | type = DNS_TYPE_SOA; | |
1c02e7ba ZJS |
2295 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", |
2296 | t->id, dns_resource_key_name(t->key)); | |
4bbc06cc | 2297 | } |
105e1512 LP |
2298 | |
2299 | if (name) { | |
2300 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2301 | ||
4bbc06cc | 2302 | soa = dns_resource_key_new(t->key->class, type, name); |
105e1512 LP |
2303 | if (!soa) |
2304 | return -ENOMEM; | |
2305 | ||
2306 | r = dns_transaction_request_dnssec_rr(t, soa); | |
2307 | if (r < 0) | |
2308 | return r; | |
2309 | } | |
2310 | } | |
2311 | ||
2312 | return dns_transaction_dnssec_is_live(t); | |
547973de LP |
2313 | } |
2314 | ||
2315 | void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { | |
547973de | 2316 | assert(t); |
547973de LP |
2317 | assert(source); |
2318 | ||
942eb2e7 LP |
2319 | /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING, |
2320 | we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If | |
2321 | the state is VALIDATING however, we should check if we are complete now. */ | |
105e1512 | 2322 | |
942eb2e7 LP |
2323 | if (t->state == DNS_TRANSACTION_VALIDATING) |
2324 | dns_transaction_process_dnssec(t); | |
547973de LP |
2325 | } |
2326 | ||
105e1512 LP |
2327 | static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { |
2328 | DnsResourceRecord *rr; | |
2329 | int ifindex, r; | |
2330 | ||
2331 | assert(t); | |
2332 | ||
2333 | /* Add all DNSKEY RRs from the answer that are validated by DS | |
2334 | * RRs from the list of validated keys to the list of | |
2335 | * validated keys. */ | |
2336 | ||
2337 | DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { | |
2338 | ||
96bb7673 | 2339 | r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); |
105e1512 LP |
2340 | if (r < 0) |
2341 | return r; | |
2342 | if (r == 0) | |
2343 | continue; | |
2344 | ||
2345 | /* If so, the DNSKEY is validated too. */ | |
2346 | r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); | |
2347 | if (r < 0) | |
2348 | return r; | |
2349 | } | |
2350 | ||
2351 | return 0; | |
2352 | } | |
2353 | ||
2354 | static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { | |
56352fe9 LP |
2355 | int r; |
2356 | ||
2357 | assert(t); | |
2358 | assert(rr); | |
2359 | ||
105e1512 LP |
2360 | /* Checks if the RR we are looking for must be signed with an |
2361 | * RRSIG. This is used for positive responses. */ | |
24a5b982 | 2362 | |
b652d4a2 | 2363 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2364 | return false; |
56352fe9 | 2365 | |
105e1512 LP |
2366 | if (dns_type_is_pseudo(rr->key->type)) |
2367 | return -EINVAL; | |
56352fe9 | 2368 | |
1c02e7ba | 2369 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2370 | if (r < 0) |
2371 | return r; | |
2372 | if (r > 0) | |
2373 | return false; | |
2374 | ||
105e1512 | 2375 | switch (rr->key->type) { |
56352fe9 | 2376 | |
105e1512 LP |
2377 | case DNS_TYPE_RRSIG: |
2378 | /* RRSIGs are the signatures themselves, they need no signing. */ | |
2379 | return false; | |
2380 | ||
2381 | case DNS_TYPE_SOA: | |
2382 | case DNS_TYPE_NS: { | |
2383 | DnsTransaction *dt; | |
2384 | Iterator i; | |
2385 | ||
b63fca62 | 2386 | /* For SOA or NS RRs we look for a matching DS transaction */ |
105e1512 LP |
2387 | |
2388 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2389 | ||
2390 | if (dt->key->class != rr->key->class) | |
2391 | continue; | |
2392 | if (dt->key->type != DNS_TYPE_DS) | |
2393 | continue; | |
2394 | ||
1c02e7ba | 2395 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2396 | if (r < 0) |
2397 | return r; | |
2398 | if (r == 0) | |
2399 | continue; | |
2400 | ||
2401 | /* We found a DS transactions for the SOA/NS | |
2402 | * RRs we are looking at. If it discovered signed DS | |
2403 | * RRs, then we need to be signed, too. */ | |
2404 | ||
097a2517 TA |
2405 | if (!dt->answer_authenticated) |
2406 | return false; | |
105e1512 | 2407 | |
097a2517 | 2408 | return dns_answer_match_key(dt->answer, dt->key, NULL); |
105e1512 LP |
2409 | } |
2410 | ||
2411 | /* We found nothing that proves this is safe to leave | |
2412 | * this unauthenticated, hence ask inist on | |
2413 | * authentication. */ | |
2414 | return true; | |
2415 | } | |
2416 | ||
b63fca62 | 2417 | case DNS_TYPE_DS: |
105e1512 LP |
2418 | case DNS_TYPE_CNAME: |
2419 | case DNS_TYPE_DNAME: { | |
2420 | const char *parent = NULL; | |
2421 | DnsTransaction *dt; | |
2422 | Iterator i; | |
2423 | ||
b63fca62 LP |
2424 | /* |
2425 | * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. | |
2426 | * | |
2427 | * DS RRs are signed if the parent is signed, hence also look at the parent SOA | |
2428 | */ | |
105e1512 LP |
2429 | |
2430 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2431 | ||
2432 | if (dt->key->class != rr->key->class) | |
2433 | continue; | |
2434 | if (dt->key->type != DNS_TYPE_SOA) | |
2435 | continue; | |
2436 | ||
2437 | if (!parent) { | |
1c02e7ba | 2438 | parent = dns_resource_key_name(rr->key); |
105e1512 LP |
2439 | r = dns_name_parent(&parent); |
2440 | if (r < 0) | |
2441 | return r; | |
2442 | if (r == 0) { | |
b63fca62 LP |
2443 | if (rr->key->type == DNS_TYPE_DS) |
2444 | return true; | |
2445 | ||
105e1512 | 2446 | /* A CNAME/DNAME without a parent? That's sooo weird. */ |
baaa35ad ZJS |
2447 | return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), |
2448 | "Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); | |
105e1512 LP |
2449 | } |
2450 | } | |
2451 | ||
1c02e7ba | 2452 | r = dns_name_equal(dns_resource_key_name(dt->key), parent); |
105e1512 LP |
2453 | if (r < 0) |
2454 | return r; | |
2455 | if (r == 0) | |
2456 | continue; | |
2457 | ||
2458 | return t->answer_authenticated; | |
2459 | } | |
2460 | ||
2461 | return true; | |
2462 | } | |
2463 | ||
2464 | default: { | |
2465 | DnsTransaction *dt; | |
2466 | Iterator i; | |
2467 | ||
b63fca62 | 2468 | /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ |
105e1512 LP |
2469 | |
2470 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2471 | ||
2472 | if (dt->key->class != rr->key->class) | |
2473 | continue; | |
2474 | if (dt->key->type != DNS_TYPE_SOA) | |
2475 | continue; | |
2476 | ||
1c02e7ba | 2477 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2478 | if (r < 0) |
2479 | return r; | |
2480 | if (r == 0) | |
2481 | continue; | |
2482 | ||
2483 | /* We found the transaction that was supposed to find | |
2484 | * the SOA RR for us. It was successful, but found no | |
2485 | * RR for us. This means we are not at a zone cut. In | |
2486 | * this case, we require authentication if the SOA | |
2487 | * lookup was authenticated too. */ | |
2488 | return t->answer_authenticated; | |
2489 | } | |
2490 | ||
2491 | return true; | |
2492 | }} | |
56352fe9 LP |
2493 | } |
2494 | ||
d33b6cf3 LP |
2495 | static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { |
2496 | DnsTransaction *dt; | |
2497 | const char *tld; | |
2498 | Iterator i; | |
2499 | int r; | |
2500 | ||
2501 | /* If DNSSEC downgrade mode is on, checks whether the | |
2502 | * specified RR is one level below a TLD we have proven not to | |
2503 | * exist. In such a case we assume that this is a private | |
2504 | * domain, and permit it. | |
2505 | * | |
2506 | * This detects cases like the Fritz!Box router networks. Each | |
2507 | * Fritz!Box router serves a private "fritz.box" zone, in the | |
2508 | * non-existing TLD "box". Requests for the "fritz.box" domain | |
2509 | * are served by the router itself, while requests for the | |
2510 | * "box" domain will result in NXDOMAIN. | |
2511 | * | |
2512 | * Note that this logic is unable to detect cases where a | |
2513 | * router serves a private DNS zone directly under | |
2514 | * non-existing TLD. In such a case we cannot detect whether | |
2515 | * the TLD is supposed to exist or not, as all requests we | |
2516 | * make for it will be answered by the router's zone, and not | |
2517 | * by the root zone. */ | |
2518 | ||
2519 | assert(t); | |
2520 | ||
2521 | if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) | |
2522 | return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ | |
2523 | ||
1c02e7ba | 2524 | tld = dns_resource_key_name(key); |
d33b6cf3 LP |
2525 | r = dns_name_parent(&tld); |
2526 | if (r < 0) | |
2527 | return r; | |
2528 | if (r == 0) | |
2529 | return false; /* Already the root domain */ | |
2530 | ||
2531 | if (!dns_name_is_single_label(tld)) | |
2532 | return false; | |
2533 | ||
2534 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2535 | ||
2536 | if (dt->key->class != key->class) | |
2537 | continue; | |
2538 | ||
1c02e7ba | 2539 | r = dns_name_equal(dns_resource_key_name(dt->key), tld); |
d33b6cf3 LP |
2540 | if (r < 0) |
2541 | return r; | |
2542 | if (r == 0) | |
2543 | continue; | |
2544 | ||
2545 | /* We found an auxiliary lookup we did for the TLD. If | |
2546 | * that returned with NXDOMAIN, we know the TLD didn't | |
2547 | * exist, and hence this might be a private zone. */ | |
2548 | ||
2549 | return dt->answer_rcode == DNS_RCODE_NXDOMAIN; | |
2550 | } | |
2551 | ||
2552 | return false; | |
2553 | } | |
2554 | ||
105e1512 | 2555 | static int dns_transaction_requires_nsec(DnsTransaction *t) { |
4bbc06cc | 2556 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
105e1512 LP |
2557 | DnsTransaction *dt; |
2558 | const char *name; | |
4bbc06cc | 2559 | uint16_t type = 0; |
105e1512 LP |
2560 | Iterator i; |
2561 | int r; | |
56352fe9 LP |
2562 | |
2563 | assert(t); | |
2564 | ||
105e1512 LP |
2565 | /* Checks if we need to insist on NSEC/NSEC3 RRs for proving |
2566 | * this negative reply */ | |
56352fe9 | 2567 | |
b652d4a2 | 2568 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2569 | return false; |
56352fe9 | 2570 | |
105e1512 LP |
2571 | if (dns_type_is_pseudo(t->key->type)) |
2572 | return -EINVAL; | |
2573 | ||
1c02e7ba | 2574 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
2575 | if (r < 0) |
2576 | return r; | |
2577 | if (r > 0) | |
2578 | return false; | |
2579 | ||
d33b6cf3 LP |
2580 | r = dns_transaction_in_private_tld(t, t->key); |
2581 | if (r < 0) | |
2582 | return r; | |
2583 | if (r > 0) { | |
2584 | /* The lookup is from a TLD that is proven not to | |
2585 | * exist, and we are in downgrade mode, hence ignore | |
13e785f7 | 2586 | * that fact that we didn't get any NSEC RRs. */ |
d33b6cf3 | 2587 | |
202b76ae ZJS |
2588 | log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", |
2589 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
d33b6cf3 LP |
2590 | return false; |
2591 | } | |
2592 | ||
1c02e7ba | 2593 | name = dns_resource_key_name(t->key); |
105e1512 | 2594 | |
4bbc06cc | 2595 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2596 | |
4bbc06cc LP |
2597 | /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed, |
2598 | * hence check the parent SOA in this case. */ | |
105e1512 LP |
2599 | |
2600 | r = dns_name_parent(&name); | |
56352fe9 LP |
2601 | if (r < 0) |
2602 | return r; | |
2603 | if (r == 0) | |
105e1512 | 2604 | return true; |
4bbc06cc LP |
2605 | |
2606 | type = DNS_TYPE_SOA; | |
2607 | ||
2608 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) | |
2609 | /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */ | |
2610 | type = DNS_TYPE_DS; | |
2611 | else | |
2612 | /* For all other negative replies, check for the SOA lookup */ | |
2613 | type = DNS_TYPE_SOA; | |
105e1512 LP |
2614 | |
2615 | /* For all other RRs we check the SOA on the same level to see | |
2616 | * if it's signed. */ | |
2617 | ||
2618 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2619 | ||
2620 | if (dt->key->class != t->key->class) | |
2621 | continue; | |
4bbc06cc | 2622 | if (dt->key->type != type) |
56352fe9 LP |
2623 | continue; |
2624 | ||
1c02e7ba | 2625 | r = dns_name_equal(dns_resource_key_name(dt->key), name); |
56352fe9 LP |
2626 | if (r < 0) |
2627 | return r; | |
105e1512 LP |
2628 | if (r == 0) |
2629 | continue; | |
2630 | ||
2631 | return dt->answer_authenticated; | |
56352fe9 LP |
2632 | } |
2633 | ||
105e1512 LP |
2634 | /* If in doubt, require NSEC/NSEC3 */ |
2635 | return true; | |
56352fe9 LP |
2636 | } |
2637 | ||
94aa7071 LP |
2638 | static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { |
2639 | DnsResourceRecord *rrsig; | |
2640 | bool found = false; | |
2641 | int r; | |
2642 | ||
2643 | /* Checks whether any of the DNSKEYs used for the RRSIGs for | |
2644 | * the specified RRset is authenticated (i.e. has a matching | |
2645 | * DS RR). */ | |
2646 | ||
1c02e7ba | 2647 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2648 | if (r < 0) |
2649 | return r; | |
2650 | if (r > 0) | |
2651 | return false; | |
2652 | ||
94aa7071 LP |
2653 | DNS_ANSWER_FOREACH(rrsig, t->answer) { |
2654 | DnsTransaction *dt; | |
2655 | Iterator i; | |
2656 | ||
2657 | r = dnssec_key_match_rrsig(rr->key, rrsig); | |
2658 | if (r < 0) | |
2659 | return r; | |
2660 | if (r == 0) | |
2661 | continue; | |
2662 | ||
2663 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2664 | ||
2665 | if (dt->key->class != rr->key->class) | |
2666 | continue; | |
2667 | ||
2668 | if (dt->key->type == DNS_TYPE_DNSKEY) { | |
2669 | ||
1c02e7ba | 2670 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2671 | if (r < 0) |
2672 | return r; | |
2673 | if (r == 0) | |
2674 | continue; | |
2675 | ||
2676 | /* OK, we found an auxiliary DNSKEY | |
2677 | * lookup. If that lookup is | |
2678 | * authenticated, report this. */ | |
2679 | ||
2680 | if (dt->answer_authenticated) | |
2681 | return true; | |
2682 | ||
2683 | found = true; | |
2684 | ||
2685 | } else if (dt->key->type == DNS_TYPE_DS) { | |
2686 | ||
1c02e7ba | 2687 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2688 | if (r < 0) |
2689 | return r; | |
2690 | if (r == 0) | |
2691 | continue; | |
2692 | ||
2693 | /* OK, we found an auxiliary DS | |
2694 | * lookup. If that lookup is | |
2695 | * authenticated and non-zero, we | |
2696 | * won! */ | |
2697 | ||
2698 | if (!dt->answer_authenticated) | |
2699 | return false; | |
2700 | ||
2701 | return dns_answer_match_key(dt->answer, dt->key, NULL); | |
2702 | } | |
2703 | } | |
2704 | } | |
2705 | ||
2706 | return found ? false : -ENXIO; | |
2707 | } | |
2708 | ||
b652d4a2 LP |
2709 | static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { |
2710 | assert(t); | |
2711 | assert(rr); | |
2712 | ||
2713 | /* We know that the root domain is signed, hence if it appears | |
2714 | * not to be signed, there's a problem with the DNS server */ | |
2715 | ||
2716 | return rr->key->class == DNS_CLASS_IN && | |
1c02e7ba | 2717 | dns_name_is_root(dns_resource_key_name(rr->key)); |
b652d4a2 LP |
2718 | } |
2719 | ||
0f87f3e8 LP |
2720 | static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { |
2721 | DnsResourceRecord *rr; | |
2722 | int r; | |
2723 | ||
2724 | assert(t); | |
2725 | ||
2726 | /* Maybe warn the user that we encountered a revoked DNSKEY | |
2727 | * for a key from our trust anchor. Note that we don't care | |
2728 | * whether the DNSKEY can be authenticated or not. It's | |
2729 | * sufficient if it is self-signed. */ | |
2730 | ||
2731 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
d424da2a | 2732 | r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); |
0f87f3e8 LP |
2733 | if (r < 0) |
2734 | return r; | |
2735 | } | |
2736 | ||
2737 | return 0; | |
2738 | } | |
2739 | ||
c9c72065 LP |
2740 | static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { |
2741 | bool changed; | |
2742 | int r; | |
2743 | ||
2744 | assert(t); | |
2745 | ||
2746 | /* Removes all DNSKEY/DS objects from t->validated_keys that | |
2747 | * our trust anchors database considers revoked. */ | |
2748 | ||
2749 | do { | |
2750 | DnsResourceRecord *rr; | |
2751 | ||
2752 | changed = false; | |
2753 | ||
2754 | DNS_ANSWER_FOREACH(rr, t->validated_keys) { | |
2755 | r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); | |
2756 | if (r < 0) | |
2757 | return r; | |
2758 | if (r > 0) { | |
2759 | r = dns_answer_remove_by_rr(&t->validated_keys, rr); | |
2760 | if (r < 0) | |
2761 | return r; | |
2762 | ||
2763 | assert(r > 0); | |
2764 | changed = true; | |
2765 | break; | |
2766 | } | |
2767 | } | |
2768 | } while (changed); | |
2769 | ||
2770 | return 0; | |
2771 | } | |
2772 | ||
942eb2e7 LP |
2773 | static int dns_transaction_copy_validated(DnsTransaction *t) { |
2774 | DnsTransaction *dt; | |
2775 | Iterator i; | |
2776 | int r; | |
2777 | ||
2778 | assert(t); | |
2779 | ||
2780 | /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */ | |
2781 | ||
2782 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2783 | ||
2784 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
2785 | continue; | |
2786 | ||
2787 | if (!dt->answer_authenticated) | |
2788 | continue; | |
2789 | ||
2790 | r = dns_answer_extend(&t->validated_keys, dt->answer); | |
2791 | if (r < 0) | |
2792 | return r; | |
2793 | } | |
2794 | ||
2795 | return 0; | |
2796 | } | |
2797 | ||
c690b20a ZJS |
2798 | typedef enum { |
2799 | DNSSEC_PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ | |
2800 | DNSSEC_PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ | |
2801 | DNSSEC_PHASE_ALL, /* Phase #3, validate everything else */ | |
2802 | } Phase; | |
2803 | ||
2804 | static int dnssec_validate_records( | |
2805 | DnsTransaction *t, | |
2806 | Phase phase, | |
2807 | bool *have_nsec, | |
2808 | DnsAnswer **validated) { | |
2809 | ||
547973de | 2810 | DnsResourceRecord *rr; |
56352fe9 | 2811 | int r; |
547973de | 2812 | |
c690b20a | 2813 | /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */ |
547973de | 2814 | |
c690b20a ZJS |
2815 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2816 | DnsResourceRecord *rrsig = NULL; | |
2817 | DnssecResult result; | |
547973de | 2818 | |
c690b20a ZJS |
2819 | switch (rr->key->type) { |
2820 | case DNS_TYPE_RRSIG: | |
2821 | continue; | |
547973de | 2822 | |
c690b20a ZJS |
2823 | case DNS_TYPE_DNSKEY: |
2824 | /* We validate DNSKEYs only in the DNSKEY and ALL phases */ | |
2825 | if (phase == DNSSEC_PHASE_NSEC) | |
2826 | continue; | |
2827 | break; | |
547973de | 2828 | |
c690b20a ZJS |
2829 | case DNS_TYPE_NSEC: |
2830 | case DNS_TYPE_NSEC3: | |
2831 | *have_nsec = true; | |
547973de | 2832 | |
c690b20a ZJS |
2833 | /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ |
2834 | if (phase == DNSSEC_PHASE_DNSKEY) | |
2835 | continue; | |
2836 | break; | |
105e1512 | 2837 | |
c690b20a ZJS |
2838 | default: |
2839 | /* We validate all other RRs only in the ALL phases */ | |
2840 | if (phase != DNSSEC_PHASE_ALL) | |
2841 | continue; | |
2842 | } | |
b652d4a2 | 2843 | |
c690b20a ZJS |
2844 | r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); |
2845 | if (r < 0) | |
2846 | return r; | |
547973de | 2847 | |
c690b20a | 2848 | log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); |
0f87f3e8 | 2849 | |
c690b20a | 2850 | if (result == DNSSEC_VALIDATED) { |
942eb2e7 | 2851 | |
c690b20a ZJS |
2852 | if (rr->key->type == DNS_TYPE_DNSKEY) { |
2853 | /* If we just validated a DNSKEY RRset, then let's add these keys to | |
2854 | * the set of validated keys for this transaction. */ | |
547973de | 2855 | |
c690b20a ZJS |
2856 | r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); |
2857 | if (r < 0) | |
2858 | return r; | |
c9c72065 | 2859 | |
c690b20a ZJS |
2860 | /* Some of the DNSKEYs we just added might already have been revoked, |
2861 | * remove them again in that case. */ | |
2862 | r = dns_transaction_invalidate_revoked_keys(t); | |
2863 | if (r < 0) | |
2864 | return r; | |
2865 | } | |
547973de | 2866 | |
c690b20a ZJS |
2867 | /* Add the validated RRset to the new list of validated |
2868 | * RRsets, and remove it from the unvalidated RRsets. | |
2869 | * We mark the RRset as authenticated and cacheable. */ | |
2870 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); | |
2871 | if (r < 0) | |
2872 | return r; | |
547973de | 2873 | |
c690b20a | 2874 | manager_dnssec_verdict(t->scope->manager, DNSSEC_SECURE, rr->key); |
0c7bff0a | 2875 | |
c690b20a ZJS |
2876 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
2877 | return 1; | |
2878 | } | |
547973de | 2879 | |
c690b20a ZJS |
2880 | /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as |
2881 | * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, | |
2882 | * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ | |
2883 | if (phase != DNSSEC_PHASE_ALL) | |
2884 | continue; | |
0c7bff0a | 2885 | |
c690b20a ZJS |
2886 | if (result == DNSSEC_VALIDATED_WILDCARD) { |
2887 | bool authenticated = false; | |
2888 | const char *source; | |
0c7bff0a | 2889 | |
c690b20a | 2890 | /* This RRset validated, but as a wildcard. This means we need |
13e785f7 | 2891 | * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */ |
0c7bff0a | 2892 | |
c690b20a ZJS |
2893 | /* First step, determine the source of synthesis */ |
2894 | r = dns_resource_record_source(rrsig, &source); | |
2895 | if (r < 0) | |
2896 | return r; | |
0c7bff0a | 2897 | |
c690b20a | 2898 | r = dnssec_test_positive_wildcard(*validated, |
1c02e7ba | 2899 | dns_resource_key_name(rr->key), |
c690b20a ZJS |
2900 | source, |
2901 | rrsig->rrsig.signer, | |
2902 | &authenticated); | |
0c7bff0a | 2903 | |
c690b20a ZJS |
2904 | /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ |
2905 | if (r == 0) | |
2906 | result = DNSSEC_INVALID; | |
2907 | else { | |
2908 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, | |
2909 | authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); | |
2910 | if (r < 0) | |
2911 | return r; | |
2912 | ||
2913 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, rr->key); | |
2914 | ||
2915 | /* Exit the loop, we dropped something from the answer, start from the beginning */ | |
2916 | return 1; | |
0c7bff0a | 2917 | } |
c690b20a | 2918 | } |
0c7bff0a | 2919 | |
c690b20a ZJS |
2920 | if (result == DNSSEC_NO_SIGNATURE) { |
2921 | r = dns_transaction_requires_rrsig(t, rr); | |
547973de LP |
2922 | if (r < 0) |
2923 | return r; | |
c690b20a ZJS |
2924 | if (r == 0) { |
2925 | /* Data does not require signing. In that case, just copy it over, | |
13e785f7 | 2926 | * but remember that this is by no means authenticated. */ |
c690b20a ZJS |
2927 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
2928 | if (r < 0) | |
2929 | return r; | |
2930 | ||
2931 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); | |
2932 | return 1; | |
2933 | } | |
547973de | 2934 | |
c690b20a ZJS |
2935 | r = dns_transaction_known_signed(t, rr); |
2936 | if (r < 0) | |
2937 | return r; | |
2938 | if (r > 0) { | |
2939 | /* This is an RR we know has to be signed. If it isn't this means | |
2940 | * the server is not attaching RRSIGs, hence complain. */ | |
547973de | 2941 | |
c690b20a | 2942 | dns_server_packet_rrsig_missing(t->server, t->current_feature_level); |
547973de | 2943 | |
c690b20a | 2944 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
547973de | 2945 | |
c690b20a | 2946 | /* Downgrading is OK? If so, just consider the information unsigned */ |
c9c72065 | 2947 | |
c690b20a | 2948 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
c9c72065 LP |
2949 | if (r < 0) |
2950 | return r; | |
547973de | 2951 | |
c690b20a ZJS |
2952 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2953 | return 1; | |
2954 | } | |
a150ff5e | 2955 | |
c690b20a ZJS |
2956 | /* Otherwise, fail */ |
2957 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
2958 | return 0; | |
f3cf586d | 2959 | } |
547973de | 2960 | |
c690b20a ZJS |
2961 | r = dns_transaction_in_private_tld(t, rr->key); |
2962 | if (r < 0) | |
2963 | return r; | |
2964 | if (r > 0) { | |
202b76ae | 2965 | char s[DNS_RESOURCE_KEY_STRING_MAX]; |
b652d4a2 | 2966 | |
c690b20a ZJS |
2967 | /* The data is from a TLD that is proven not to exist, and we are in downgrade |
2968 | * mode, hence ignore the fact that this was not signed. */ | |
0c7bff0a | 2969 | |
202b76ae ZJS |
2970 | log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", |
2971 | dns_resource_key_to_string(rr->key, s, sizeof s)); | |
0c7bff0a | 2972 | |
c690b20a | 2973 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
0c7bff0a LP |
2974 | if (r < 0) |
2975 | return r; | |
0c7bff0a | 2976 | |
c690b20a ZJS |
2977 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2978 | return 1; | |
2979 | } | |
2980 | } | |
0c7bff0a | 2981 | |
c690b20a ZJS |
2982 | if (IN_SET(result, |
2983 | DNSSEC_MISSING_KEY, | |
2984 | DNSSEC_SIGNATURE_EXPIRED, | |
2985 | DNSSEC_UNSUPPORTED_ALGORITHM)) { | |
0c7bff0a | 2986 | |
c690b20a ZJS |
2987 | r = dns_transaction_dnskey_authenticated(t, rr); |
2988 | if (r < 0 && r != -ENXIO) | |
2989 | return r; | |
2990 | if (r == 0) { | |
2991 | /* The DNSKEY transaction was not authenticated, this means there's | |
2992 | * no DS for this, which means it's OK if no keys are found for this signature. */ | |
0c7bff0a | 2993 | |
c690b20a | 2994 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
f3cf586d LP |
2995 | if (r < 0) |
2996 | return r; | |
b652d4a2 | 2997 | |
c690b20a ZJS |
2998 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2999 | return 1; | |
3000 | } | |
3001 | } | |
b652d4a2 | 3002 | |
c690b20a ZJS |
3003 | r = dns_transaction_is_primary_response(t, rr); |
3004 | if (r < 0) | |
3005 | return r; | |
3006 | if (r > 0) { | |
3007 | /* Look for a matching DNAME for this CNAME */ | |
3008 | r = dns_answer_has_dname_for_cname(t->answer, rr); | |
3009 | if (r < 0) | |
3010 | return r; | |
3011 | if (r == 0) { | |
3012 | /* Also look among the stuff we already validated */ | |
3013 | r = dns_answer_has_dname_for_cname(*validated, rr); | |
f3cf586d LP |
3014 | if (r < 0) |
3015 | return r; | |
c690b20a | 3016 | } |
d33b6cf3 | 3017 | |
c690b20a ZJS |
3018 | if (r == 0) { |
3019 | if (IN_SET(result, | |
3020 | DNSSEC_INVALID, | |
3021 | DNSSEC_SIGNATURE_EXPIRED, | |
3022 | DNSSEC_NO_SIGNATURE)) | |
3023 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, rr->key); | |
3024 | else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ | |
3025 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, rr->key); | |
3026 | ||
3027 | /* This is a primary response to our question, and it failed validation. | |
3028 | * That's fatal. */ | |
3029 | t->answer_dnssec_result = result; | |
3030 | return 0; | |
3031 | } | |
d33b6cf3 | 3032 | |
c690b20a ZJS |
3033 | /* This is a primary response, but we do have a DNAME RR |
3034 | * in the RR that can replay this CNAME, hence rely on | |
3035 | * that, and we can remove the CNAME in favour of it. */ | |
3036 | } | |
d33b6cf3 | 3037 | |
c690b20a ZJS |
3038 | /* This is just some auxiliary data. Just remove the RRset and continue. */ |
3039 | r = dns_answer_remove_by_key(&t->answer, rr->key); | |
3040 | if (r < 0) | |
3041 | return r; | |
d33b6cf3 | 3042 | |
c690b20a ZJS |
3043 | /* We dropped something from the answer, start from the beginning. */ |
3044 | return 1; | |
3045 | } | |
f3cf586d | 3046 | |
c690b20a ZJS |
3047 | return 2; /* Finito. */ |
3048 | } | |
94aa7071 | 3049 | |
c690b20a ZJS |
3050 | int dns_transaction_validate_dnssec(DnsTransaction *t) { |
3051 | _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; | |
3052 | Phase phase; | |
3053 | DnsAnswerFlags flags; | |
3054 | int r; | |
202b76ae | 3055 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
94aa7071 | 3056 | |
c690b20a | 3057 | assert(t); |
94aa7071 | 3058 | |
c690b20a ZJS |
3059 | /* We have now collected all DS and DNSKEY RRs in |
3060 | * t->validated_keys, let's see which RRs we can now | |
3061 | * authenticate with that. */ | |
94aa7071 | 3062 | |
c690b20a ZJS |
3063 | if (t->scope->dnssec_mode == DNSSEC_NO) |
3064 | return 0; | |
a150ff5e | 3065 | |
c690b20a ZJS |
3066 | /* Already validated */ |
3067 | if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) | |
3068 | return 0; | |
105e1512 | 3069 | |
c690b20a ZJS |
3070 | /* Our own stuff needs no validation */ |
3071 | if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { | |
3072 | t->answer_dnssec_result = DNSSEC_VALIDATED; | |
3073 | t->answer_authenticated = true; | |
3074 | return 0; | |
3075 | } | |
a150ff5e | 3076 | |
c690b20a ZJS |
3077 | /* Cached stuff is not affected by validation. */ |
3078 | if (t->answer_source != DNS_TRANSACTION_NETWORK) | |
3079 | return 0; | |
f3cf586d | 3080 | |
c690b20a ZJS |
3081 | if (!dns_transaction_dnssec_supported_full(t)) { |
3082 | /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ | |
3083 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
d001e0a3 | 3084 | log_debug("Not validating response for %" PRIu16 ", used server feature level does not support DNSSEC.", t->id); |
c690b20a ZJS |
3085 | return 0; |
3086 | } | |
f3cf586d | 3087 | |
202b76ae ZJS |
3088 | log_debug("Validating response from transaction %" PRIu16 " (%s).", |
3089 | t->id, | |
3090 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
547973de | 3091 | |
c690b20a ZJS |
3092 | /* First, see if this response contains any revoked trust |
3093 | * anchors we care about */ | |
3094 | r = dns_transaction_check_revoked_trust_anchors(t); | |
3095 | if (r < 0) | |
3096 | return r; | |
43e6779a | 3097 | |
c690b20a ZJS |
3098 | /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */ |
3099 | r = dns_transaction_copy_validated(t); | |
3100 | if (r < 0) | |
3101 | return r; | |
43e6779a | 3102 | |
c690b20a ZJS |
3103 | /* Second, see if there are DNSKEYs we already know a |
3104 | * validated DS for. */ | |
3105 | r = dns_transaction_validate_dnskey_by_ds(t); | |
3106 | if (r < 0) | |
3107 | return r; | |
43e6779a | 3108 | |
c690b20a ZJS |
3109 | /* Fourth, remove all DNSKEY and DS RRs again that our trust |
3110 | * anchor says are revoked. After all we might have marked | |
3111 | * some keys revoked above, but they might still be lingering | |
3112 | * in our validated_keys list. */ | |
3113 | r = dns_transaction_invalidate_revoked_keys(t); | |
3114 | if (r < 0) | |
3115 | return r; | |
f3cf586d | 3116 | |
c690b20a ZJS |
3117 | phase = DNSSEC_PHASE_DNSKEY; |
3118 | for (;;) { | |
3119 | bool have_nsec = false; | |
f3cf586d | 3120 | |
c690b20a ZJS |
3121 | r = dnssec_validate_records(t, phase, &have_nsec, &validated); |
3122 | if (r <= 0) | |
3123 | return r; | |
547973de | 3124 | |
c690b20a ZJS |
3125 | /* Try again as long as we managed to achieve something */ |
3126 | if (r == 1) | |
547973de LP |
3127 | continue; |
3128 | ||
c690b20a | 3129 | if (phase == DNSSEC_PHASE_DNSKEY && have_nsec) { |
0c7bff0a | 3130 | /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ |
c690b20a | 3131 | phase = DNSSEC_PHASE_NSEC; |
0c7bff0a LP |
3132 | continue; |
3133 | } | |
3134 | ||
c690b20a ZJS |
3135 | if (phase != DNSSEC_PHASE_ALL) { |
3136 | /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. | |
3137 | * Note that in this third phase we start to remove RRs we couldn't validate. */ | |
3138 | phase = DNSSEC_PHASE_ALL; | |
56352fe9 | 3139 | continue; |
547973de LP |
3140 | } |
3141 | ||
56352fe9 | 3142 | /* We're done */ |
547973de LP |
3143 | break; |
3144 | } | |
3145 | ||
3146 | dns_answer_unref(t->answer); | |
1cc6c93a | 3147 | t->answer = TAKE_PTR(validated); |
547973de | 3148 | |
72667f08 LP |
3149 | /* At this point the answer only contains validated |
3150 | * RRsets. Now, let's see if it actually answers the question | |
3151 | * we asked. If so, great! If it doesn't, then see if | |
3152 | * NSEC/NSEC3 can prove this. */ | |
105e1512 | 3153 | r = dns_transaction_has_positive_answer(t, &flags); |
72667f08 | 3154 | if (r > 0) { |
105e1512 LP |
3155 | /* Yes, it answers the question! */ |
3156 | ||
3157 | if (flags & DNS_ANSWER_AUTHENTICATED) { | |
3158 | /* The answer is fully authenticated, yay. */ | |
019036a4 | 3159 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
105e1512 LP |
3160 | t->answer_rcode = DNS_RCODE_SUCCESS; |
3161 | t->answer_authenticated = true; | |
3162 | } else { | |
3163 | /* The answer is not fully authenticated. */ | |
019036a4 | 3164 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
3165 | t->answer_authenticated = false; |
3166 | } | |
3167 | ||
72667f08 LP |
3168 | } else if (r == 0) { |
3169 | DnssecNsecResult nr; | |
ed29bfdc | 3170 | bool authenticated = false; |
72667f08 LP |
3171 | |
3172 | /* Bummer! Let's check NSEC/NSEC3 */ | |
0c7bff0a | 3173 | r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); |
72667f08 LP |
3174 | if (r < 0) |
3175 | return r; | |
3176 | ||
3177 | switch (nr) { | |
3178 | ||
3179 | case DNSSEC_NSEC_NXDOMAIN: | |
3180 | /* NSEC proves the domain doesn't exist. Very good. */ | |
202b76ae | 3181 | log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3182 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3183 | t->answer_rcode = DNS_RCODE_NXDOMAIN; |
ed29bfdc | 3184 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3185 | |
59c5b597 | 3186 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3187 | break; |
3188 | ||
3189 | case DNSSEC_NSEC_NODATA: | |
3190 | /* NSEC proves that there's no data here, very good. */ | |
202b76ae | 3191 | log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3192 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3193 | t->answer_rcode = DNS_RCODE_SUCCESS; |
ed29bfdc | 3194 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3195 | |
59c5b597 | 3196 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3197 | break; |
3198 | ||
105e1512 LP |
3199 | case DNSSEC_NSEC_OPTOUT: |
3200 | /* NSEC3 says the data might not be signed */ | |
202b76ae | 3201 | log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3202 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3203 | t->answer_authenticated = false; |
7aa8ce98 | 3204 | |
59c5b597 | 3205 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3206 | break; |
3207 | ||
72667f08 LP |
3208 | case DNSSEC_NSEC_NO_RR: |
3209 | /* No NSEC data? Bummer! */ | |
105e1512 LP |
3210 | |
3211 | r = dns_transaction_requires_nsec(t); | |
3212 | if (r < 0) | |
3213 | return r; | |
7aa8ce98 | 3214 | if (r > 0) { |
019036a4 | 3215 | t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; |
59c5b597 | 3216 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
7aa8ce98 | 3217 | } else { |
019036a4 | 3218 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3219 | t->answer_authenticated = false; |
59c5b597 | 3220 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3221 | } |
3222 | ||
3223 | break; | |
3224 | ||
3225 | case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: | |
3226 | /* We don't know the NSEC3 algorithm used? */ | |
019036a4 | 3227 | t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; |
59c5b597 | 3228 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, t->key); |
72667f08 LP |
3229 | break; |
3230 | ||
3231 | case DNSSEC_NSEC_FOUND: | |
146035b3 | 3232 | case DNSSEC_NSEC_CNAME: |
72667f08 | 3233 | /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ |
019036a4 | 3234 | t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; |
59c5b597 | 3235 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
72667f08 LP |
3236 | break; |
3237 | ||
3238 | default: | |
3239 | assert_not_reached("Unexpected NSEC result."); | |
3240 | } | |
3241 | } | |
3242 | ||
547973de LP |
3243 | return 1; |
3244 | } | |
3245 | ||
ec2c5e43 LP |
3246 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { |
3247 | [DNS_TRANSACTION_NULL] = "null", | |
3248 | [DNS_TRANSACTION_PENDING] = "pending", | |
547973de | 3249 | [DNS_TRANSACTION_VALIDATING] = "validating", |
3bbdc31d | 3250 | [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", |
ec2c5e43 LP |
3251 | [DNS_TRANSACTION_SUCCESS] = "success", |
3252 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
3253 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
3254 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
3255 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
7cc6ed7b | 3256 | [DNS_TRANSACTION_ERRNO] = "errno", |
ec2c5e43 | 3257 | [DNS_TRANSACTION_ABORTED] = "aborted", |
547973de | 3258 | [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", |
b2b796b8 | 3259 | [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", |
91adc4db | 3260 | [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", |
edbcc1fd | 3261 | [DNS_TRANSACTION_NETWORK_DOWN] = "network-down", |
0791110f | 3262 | [DNS_TRANSACTION_NOT_FOUND] = "not-found", |
ec2c5e43 LP |
3263 | }; |
3264 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); | |
c3bc53e6 LP |
3265 | |
3266 | static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { | |
3267 | [DNS_TRANSACTION_NETWORK] = "network", | |
3268 | [DNS_TRANSACTION_CACHE] = "cache", | |
3269 | [DNS_TRANSACTION_ZONE] = "zone", | |
0d2cd476 | 3270 | [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", |
c3bc53e6 LP |
3271 | }; |
3272 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); |