1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 #include "sd-messages.h"
6 #include "alloc-util.h"
7 #include "dns-domain.h"
8 #include "errno-list.h"
10 #include "random-util.h"
11 #include "resolved-dns-cache.h"
12 #include "resolved-dns-transaction.h"
13 #include "resolved-llmnr.h"
14 #include "string-table.h"
17 #include <gnutls/socket.h>
20 #define TRANSACTIONS_MAX 4096
21 #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC)
23 /* After how much time to repeat classic DNS requests */
24 #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX)
26 static void dns_transaction_reset_answer(DnsTransaction
*t
) {
29 t
->received
= dns_packet_unref(t
->received
);
30 t
->answer
= dns_answer_unref(t
->answer
);
32 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
33 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
34 t
->answer_authenticated
= false;
35 t
->answer_nsec_ttl
= (uint32_t) -1;
39 static void dns_transaction_flush_dnssec_transactions(DnsTransaction
*t
) {
44 while ((z
= set_steal_first(t
->dnssec_transactions
))) {
45 set_remove(z
->notify_transactions
, t
);
46 set_remove(z
->notify_transactions_done
, t
);
47 dns_transaction_gc(z
);
51 static void dns_transaction_close_connection(DnsTransaction
*t
) {
55 /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */
56 LIST_REMOVE(transactions_by_stream
, t
->stream
->transactions
, t
);
58 /* Remove packet in case it's still in the queue */
59 dns_packet_unref(ordered_set_remove(t
->stream
->write_queue
, t
->sent
));
61 t
->stream
= dns_stream_unref(t
->stream
);
64 t
->dns_udp_event_source
= sd_event_source_unref(t
->dns_udp_event_source
);
65 t
->dns_udp_fd
= safe_close(t
->dns_udp_fd
);
68 static void dns_transaction_stop_timeout(DnsTransaction
*t
) {
71 t
->timeout_event_source
= sd_event_source_unref(t
->timeout_event_source
);
74 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
) {
82 log_debug("Freeing transaction %" PRIu16
".", t
->id
);
84 dns_transaction_close_connection(t
);
85 dns_transaction_stop_timeout(t
);
87 dns_packet_unref(t
->sent
);
88 dns_transaction_reset_answer(t
);
90 dns_server_unref(t
->server
);
93 hashmap_remove_value(t
->scope
->transactions_by_key
, t
->key
, t
);
94 LIST_REMOVE(transactions_by_scope
, t
->scope
->transactions
, t
);
97 hashmap_remove(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
100 while ((c
= set_steal_first(t
->notify_query_candidates
)))
101 set_remove(c
->transactions
, t
);
102 set_free(t
->notify_query_candidates
);
104 while ((c
= set_steal_first(t
->notify_query_candidates_done
)))
105 set_remove(c
->transactions
, t
);
106 set_free(t
->notify_query_candidates_done
);
108 while ((i
= set_steal_first(t
->notify_zone_items
)))
109 i
->probe_transaction
= NULL
;
110 set_free(t
->notify_zone_items
);
112 while ((i
= set_steal_first(t
->notify_zone_items_done
)))
113 i
->probe_transaction
= NULL
;
114 set_free(t
->notify_zone_items_done
);
116 while ((z
= set_steal_first(t
->notify_transactions
)))
117 set_remove(z
->dnssec_transactions
, t
);
118 set_free(t
->notify_transactions
);
120 while ((z
= set_steal_first(t
->notify_transactions_done
)))
121 set_remove(z
->dnssec_transactions
, t
);
122 set_free(t
->notify_transactions_done
);
124 dns_transaction_flush_dnssec_transactions(t
);
125 set_free(t
->dnssec_transactions
);
127 dns_answer_unref(t
->validated_keys
);
128 dns_resource_key_unref(t
->key
);
133 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction
*, dns_transaction_free
);
135 bool dns_transaction_gc(DnsTransaction
*t
) {
141 if (set_isempty(t
->notify_query_candidates
) &&
142 set_isempty(t
->notify_query_candidates_done
) &&
143 set_isempty(t
->notify_zone_items
) &&
144 set_isempty(t
->notify_zone_items_done
) &&
145 set_isempty(t
->notify_transactions
) &&
146 set_isempty(t
->notify_transactions_done
)) {
147 dns_transaction_free(t
);
154 static uint16_t pick_new_id(Manager
*m
) {
157 /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of
158 * transactions, and it's much lower than the space of IDs. */
160 assert_cc(TRANSACTIONS_MAX
< 0xFFFF);
163 random_bytes(&new_id
, sizeof(new_id
));
164 while (new_id
== 0 ||
165 hashmap_get(m
->dns_transactions
, UINT_TO_PTR(new_id
)));
170 int dns_transaction_new(DnsTransaction
**ret
, DnsScope
*s
, DnsResourceKey
*key
) {
171 _cleanup_(dns_transaction_freep
) DnsTransaction
*t
= NULL
;
178 /* Don't allow looking up invalid or pseudo RRs */
179 if (!dns_type_is_valid_query(key
->type
))
181 if (dns_type_is_obsolete(key
->type
))
184 /* We only support the IN class */
185 if (!IN_SET(key
->class, DNS_CLASS_IN
, DNS_CLASS_ANY
))
188 if (hashmap_size(s
->manager
->dns_transactions
) >= TRANSACTIONS_MAX
)
191 r
= hashmap_ensure_allocated(&s
->manager
->dns_transactions
, NULL
);
195 r
= hashmap_ensure_allocated(&s
->transactions_by_key
, &dns_resource_key_hash_ops
);
199 t
= new0(DnsTransaction
, 1);
204 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
205 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
206 t
->answer_nsec_ttl
= (uint32_t) -1;
207 t
->key
= dns_resource_key_ref(key
);
208 t
->current_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
209 t
->clamp_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
211 t
->id
= pick_new_id(s
->manager
);
213 r
= hashmap_put(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), t
);
219 r
= hashmap_replace(s
->transactions_by_key
, t
->key
, t
);
221 hashmap_remove(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
225 LIST_PREPEND(transactions_by_scope
, s
->transactions
, t
);
228 s
->manager
->n_transactions_total
++;
238 static void dns_transaction_shuffle_id(DnsTransaction
*t
) {
242 /* Pick a new ID for this transaction. */
244 new_id
= pick_new_id(t
->scope
->manager
);
245 assert_se(hashmap_remove_and_put(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), UINT_TO_PTR(new_id
), t
) >= 0);
247 log_debug("Transaction %" PRIu16
" is now %" PRIu16
".", t
->id
, new_id
);
250 /* Make sure we generate a new packet with the new ID */
251 t
->sent
= dns_packet_unref(t
->sent
);
254 static void dns_transaction_tentative(DnsTransaction
*t
, DnsPacket
*p
) {
255 _cleanup_free_
char *pretty
= NULL
;
256 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
262 if (manager_our_packet(t
->scope
->manager
, p
) != 0)
265 (void) in_addr_to_string(p
->family
, &p
->sender
, &pretty
);
267 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s got tentative packet from %s.",
269 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
270 dns_protocol_to_string(t
->scope
->protocol
),
271 t
->scope
->link
? t
->scope
->link
->name
: "*",
272 af_to_name_short(t
->scope
->family
),
275 /* RFC 4795, Section 4.1 says that the peer with the
276 * lexicographically smaller IP address loses */
277 if (memcmp(&p
->sender
, &p
->destination
, FAMILY_ADDRESS_SIZE(p
->family
)) >= 0) {
278 log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
282 log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
286 while ((z
= set_first(t
->notify_zone_items
))) {
287 /* First, make sure the zone item drops the reference
289 dns_zone_item_probe_stop(z
);
291 /* Secondly, report this as conflict, so that we might
292 * look for a different hostname */
293 dns_zone_item_conflict(z
);
297 dns_transaction_gc(t
);
300 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
) {
301 DnsQueryCandidate
*c
;
305 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
308 assert(!DNS_TRANSACTION_IS_LIVE(state
));
310 if (state
== DNS_TRANSACTION_DNSSEC_FAILED
) {
311 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
);
313 log_struct(LOG_NOTICE
,
314 "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR
,
315 LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str
, dnssec_result_to_string(t
->answer_dnssec_result
)),
316 "DNS_TRANSACTION=%" PRIu16
, t
->id
,
317 "DNS_QUESTION=%s", key_str
,
318 "DNSSEC_RESULT=%s", dnssec_result_to_string(t
->answer_dnssec_result
),
319 "DNS_SERVER=%s", dns_server_string(t
->server
),
320 "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t
->server
->possible_feature_level
));
323 /* Note that this call might invalidate the query. Callers
324 * should hence not attempt to access the query or transaction
325 * after calling this function. */
327 if (state
== DNS_TRANSACTION_ERRNO
)
328 st
= errno_to_name(t
->answer_errno
);
330 st
= dns_transaction_state_to_string(state
);
332 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).",
334 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
335 dns_protocol_to_string(t
->scope
->protocol
),
336 t
->scope
->link
? t
->scope
->link
->name
: "*",
337 af_to_name_short(t
->scope
->family
),
339 t
->answer_source
< 0 ? "none" : dns_transaction_source_to_string(t
->answer_source
),
340 t
->answer_authenticated
? "authenticated" : "unsigned");
344 dns_transaction_close_connection(t
);
345 dns_transaction_stop_timeout(t
);
347 /* Notify all queries that are interested, but make sure the
348 * transaction isn't freed while we are still looking at it */
351 SET_FOREACH_MOVE(c
, t
->notify_query_candidates_done
, t
->notify_query_candidates
)
352 dns_query_candidate_notify(c
);
353 SWAP_TWO(t
->notify_query_candidates
, t
->notify_query_candidates_done
);
355 SET_FOREACH_MOVE(z
, t
->notify_zone_items_done
, t
->notify_zone_items
)
356 dns_zone_item_notify(z
);
357 SWAP_TWO(t
->notify_zone_items
, t
->notify_zone_items_done
);
358 if (t
->probing
&& t
->state
== DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
)
359 (void) dns_scope_announce(t
->scope
, false);
361 SET_FOREACH_MOVE(d
, t
->notify_transactions_done
, t
->notify_transactions
)
362 dns_transaction_notify(d
, t
);
363 SWAP_TWO(t
->notify_transactions
, t
->notify_transactions_done
);
366 dns_transaction_gc(t
);
369 static int dns_transaction_pick_server(DnsTransaction
*t
) {
373 assert(t
->scope
->protocol
== DNS_PROTOCOL_DNS
);
375 /* Pick a DNS server and a feature level for it. */
377 server
= dns_scope_get_dns_server(t
->scope
);
381 /* If we changed the server invalidate the feature level clamping, as the new server might have completely
382 * different properties. */
383 if (server
!= t
->server
)
384 t
->clamp_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
386 t
->current_feature_level
= dns_server_possible_feature_level(server
);
388 /* Clamp the feature level if that is requested. */
389 if (t
->clamp_feature_level
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
&&
390 t
->current_feature_level
> t
->clamp_feature_level
)
391 t
->current_feature_level
= t
->clamp_feature_level
;
393 log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t
->current_feature_level
), t
->id
);
395 if (server
== t
->server
)
398 dns_server_unref(t
->server
);
399 t
->server
= dns_server_ref(server
);
401 t
->n_picked_servers
++;
403 log_debug("Using DNS server %s for transaction %u.", dns_server_string(t
->server
), t
->id
);
408 static void dns_transaction_retry(DnsTransaction
*t
, bool next_server
) {
413 log_debug("Retrying transaction %" PRIu16
".", t
->id
);
415 /* Before we try again, switch to a new server. */
417 dns_scope_next_dns_server(t
->scope
);
419 r
= dns_transaction_go(t
);
421 t
->answer_errno
= -r
;
422 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
426 static int dns_transaction_maybe_restart(DnsTransaction
*t
) {
431 /* Returns > 0 if the transaction was restarted, 0 if not */
436 if (t
->current_feature_level
<= dns_server_possible_feature_level(t
->server
))
439 /* The server's current feature level is lower than when we sent the original query. We learnt something from
440 the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
441 restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
442 OPT RR or DO bit. One of these cases is documented here, for example:
443 https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
445 log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
446 dns_transaction_shuffle_id(t
);
448 r
= dns_transaction_go(t
);
455 static void on_transaction_stream_error(DnsTransaction
*t
, int error
) {
458 dns_transaction_close_connection(t
);
460 if (ERRNO_IS_DISCONNECT(error
)) {
461 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
) {
462 /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the
463 * question on this scope. */
464 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
468 dns_transaction_retry(t
, true);
472 t
->answer_errno
= error
;
473 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
477 static int dns_transaction_on_stream_packet(DnsTransaction
*t
, DnsPacket
*p
) {
481 dns_transaction_close_connection(t
);
483 if (dns_packet_validate_reply(p
) <= 0) {
484 log_debug("Invalid TCP reply packet.");
485 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
489 dns_scope_check_conflicts(t
->scope
, p
);
492 dns_transaction_process_reply(t
, p
);
495 /* If the response wasn't useful, then complete the transition
496 * now. After all, we are the worst feature set now with TCP
497 * sockets, and there's really no point in retrying. */
498 if (t
->state
== DNS_TRANSACTION_PENDING
)
499 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
501 dns_transaction_gc(t
);
506 static int on_stream_connection(DnsStream
*s
) {
508 /* Store TLS Ticket for faster succesive TLS handshakes */
509 if (s
->tls_session
&& s
->server
) {
510 if (s
->server
->tls_session_data
.data
)
511 gnutls_free(s
->server
->tls_session_data
.data
);
513 gnutls_session_get_data2(s
->tls_session
, &s
->server
->tls_session_data
);
520 static int on_stream_complete(DnsStream
*s
, int error
) {
521 DnsTransaction
*t
, *n
;
524 /* Do not let new transactions use this stream */
525 if (s
->server
&& s
->server
->stream
== s
)
526 s
->server
->stream
= dns_stream_unref(s
->server
->stream
);
528 if (ERRNO_IS_DISCONNECT(error
) && s
->protocol
!= DNS_PROTOCOL_LLMNR
) {
531 log_debug_errno(error
, "Connection failure for DNS TCP stream: %m");
533 if (s
->transactions
) {
535 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &usec
) >= 0);
536 dns_server_packet_lost(t
->server
, IPPROTO_TCP
, t
->current_feature_level
);
540 LIST_FOREACH_SAFE(transactions_by_stream
, t
, n
, s
->transactions
)
542 on_transaction_stream_error(t
, error
);
543 else if (DNS_PACKET_ID(s
->read_packet
) == t
->id
)
544 /* As each transaction have a unique id the return code is only set once */
545 r
= dns_transaction_on_stream_packet(t
, s
->read_packet
);
550 static int dns_stream_on_packet(DnsStream
*s
) {
551 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
555 /* Take ownership of packet to be able to receive new packets */
556 p
= TAKE_PTR(s
->read_packet
);
559 t
= hashmap_get(s
->manager
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
561 /* Ignore incorrect transaction id as transaction can have been canceled */
563 r
= dns_transaction_on_stream_packet(t
, p
);
565 if (dns_packet_validate_reply(p
) <= 0) {
566 log_debug("Invalid TCP reply packet.");
567 on_stream_complete(s
, 0);
575 static int dns_transaction_emit_tcp(DnsTransaction
*t
) {
576 _cleanup_close_
int fd
= -1;
577 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
578 union sockaddr_union sa
;
586 dns_transaction_close_connection(t
);
588 switch (t
->scope
->protocol
) {
590 case DNS_PROTOCOL_DNS
:
591 r
= dns_transaction_pick_server(t
);
595 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(t
->key
->type
))
598 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
602 if (t
->server
->stream
&& (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) == t
->server
->stream
->encrypted
))
603 s
= dns_stream_ref(t
->server
->stream
);
605 fd
= dns_scope_socket_tcp(t
->scope
, AF_UNSPEC
, NULL
, t
->server
, DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) ? 853 : 53, &sa
);
609 case DNS_PROTOCOL_LLMNR
:
610 /* When we already received a reply to this (but it was truncated), send to its sender address */
612 fd
= dns_scope_socket_tcp(t
->scope
, t
->received
->family
, &t
->received
->sender
, NULL
, t
->received
->sender_port
, &sa
);
614 union in_addr_union address
;
615 int family
= AF_UNSPEC
;
617 /* Otherwise, try to talk to the owner of a
618 * the IP address, in case this is a reverse
621 r
= dns_name_address(dns_resource_key_name(t
->key
), &family
, &address
);
626 if (family
!= t
->scope
->family
)
629 fd
= dns_scope_socket_tcp(t
->scope
, family
, &address
, NULL
, LLMNR_PORT
, &sa
);
635 return -EAFNOSUPPORT
;
642 r
= dns_stream_new(t
->scope
->manager
, &s
, t
->scope
->protocol
, fd
, &sa
);
649 dns_stream_unref(t
->server
->stream
);
650 t
->server
->stream
= dns_stream_ref(s
);
651 s
->server
= dns_server_ref(t
->server
);
655 if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
)) {
656 r
= gnutls_init(&gs
, GNUTLS_CLIENT
| GNUTLS_ENABLE_FALSE_START
| GNUTLS_NONBLOCK
);
660 /* As DNS-over-TLS is a recent protocol, older TLS versions can be disabled */
661 r
= gnutls_priority_set_direct(gs
, "NORMAL:-VERS-ALL:+VERS-TLS1.2", NULL
);
665 r
= gnutls_credentials_set(gs
, GNUTLS_CRD_CERTIFICATE
, t
->server
->tls_cert_cred
);
669 if (t
->server
&& t
->server
->tls_session_data
.size
> 0)
670 gnutls_session_set_data(gs
, t
->server
->tls_session_data
.data
, t
->server
->tls_session_data
.size
);
672 gnutls_handshake_set_timeout(gs
, GNUTLS_DEFAULT_HANDSHAKE_TIMEOUT
);
674 r
= dns_stream_connect_tls(s
, gs
);
680 s
->on_connection
= on_stream_connection
;
681 s
->complete
= on_stream_complete
;
682 s
->on_packet
= dns_stream_on_packet
;
684 /* The interface index is difficult to determine if we are
685 * connecting to the local host, hence fill this in right away
686 * instead of determining it from the socket */
687 s
->ifindex
= dns_scope_ifindex(t
->scope
);
690 t
->stream
= TAKE_PTR(s
);
691 LIST_PREPEND(transactions_by_stream
, t
->stream
->transactions
, t
);
693 r
= dns_stream_write_packet(t
->stream
, t
->sent
);
695 dns_transaction_close_connection(t
);
699 dns_transaction_reset_answer(t
);
701 t
->tried_stream
= true;
706 static void dns_transaction_cache_answer(DnsTransaction
*t
) {
709 /* For mDNS we cache whenever we get the packet, rather than
710 * in each transaction. */
711 if (!IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
))
714 /* Caching disabled? */
715 if (!t
->scope
->manager
->enable_cache
)
718 /* We never cache if this packet is from the local host, under
719 * the assumption that a locally running DNS server would
720 * cache this anyway, and probably knows better when to flush
721 * the cache then we could. */
722 if (!DNS_PACKET_SHALL_CACHE(t
->received
))
725 dns_cache_put(&t
->scope
->cache
,
729 t
->answer_authenticated
,
733 &t
->received
->sender
);
736 static bool dns_transaction_dnssec_is_live(DnsTransaction
*t
) {
742 SET_FOREACH(dt
, t
->dnssec_transactions
, i
)
743 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
749 static int dns_transaction_dnssec_ready(DnsTransaction
*t
) {
755 /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
756 * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
758 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
762 case DNS_TRANSACTION_NULL
:
763 case DNS_TRANSACTION_PENDING
:
764 case DNS_TRANSACTION_VALIDATING
:
768 case DNS_TRANSACTION_RCODE_FAILURE
:
769 if (!IN_SET(dt
->answer_rcode
, DNS_RCODE_NXDOMAIN
, DNS_RCODE_SERVFAIL
)) {
770 log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt
->answer_rcode
));
774 /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers
775 * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS
776 * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar
777 * RRs to make unsigned proofs. */
779 case DNS_TRANSACTION_SUCCESS
:
783 case DNS_TRANSACTION_DNSSEC_FAILED
:
784 /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
785 * validationr result */
787 log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt
->answer_dnssec_result
));
788 t
->answer_dnssec_result
= dt
->answer_dnssec_result
; /* Copy error code over */
789 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
793 log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt
->state
));
798 /* All is ready, we can go and validate */
802 t
->answer_dnssec_result
= DNSSEC_FAILED_AUXILIARY
;
803 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
807 static void dns_transaction_process_dnssec(DnsTransaction
*t
) {
812 /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
813 r
= dns_transaction_dnssec_ready(t
);
816 if (r
== 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
819 /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
820 * restart the lookup immediately. */
821 r
= dns_transaction_maybe_restart(t
);
824 if (r
> 0) /* Transaction got restarted... */
827 /* All our auxiliary DNSSEC transactions are complete now. Try
828 * to validate our RRset now. */
829 r
= dns_transaction_validate_dnssec(t
);
831 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
837 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
&&
838 t
->scope
->dnssec_mode
== DNSSEC_YES
) {
840 /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe
843 if (t
->n_picked_servers
< dns_scope_get_n_dns_servers(t
->scope
)) {
844 /* We tried fewer servers on this transaction than we know, let's try another one then */
845 dns_transaction_retry(t
, true);
849 /* OK, let's give up, apparently all servers we tried didn't work. */
850 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
854 if (!IN_SET(t
->answer_dnssec_result
,
855 _DNSSEC_RESULT_INVALID
, /* No DNSSEC validation enabled */
856 DNSSEC_VALIDATED
, /* Answer is signed and validated successfully */
857 DNSSEC_UNSIGNED
, /* Answer is right-fully unsigned */
858 DNSSEC_INCOMPATIBLE_SERVER
)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
859 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
863 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
)
864 dns_server_warn_downgrade(t
->server
);
866 dns_transaction_cache_answer(t
);
868 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
869 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
871 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
876 t
->answer_errno
= -r
;
877 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
880 static int dns_transaction_has_positive_answer(DnsTransaction
*t
, DnsAnswerFlags
*flags
) {
885 /* Checks whether the answer is positive, i.e. either a direct
886 * answer to the question, or a CNAME/DNAME for it */
888 r
= dns_answer_match_key(t
->answer
, t
->key
, flags
);
892 r
= dns_answer_find_cname_or_dname(t
->answer
, t
->key
, NULL
, flags
);
899 static int dns_transaction_fix_rcode(DnsTransaction
*t
) {
904 /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the
905 * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a
906 * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first
907 * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when
908 * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle
909 * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a
910 * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server
911 * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an
912 * incomplete CNAME/DNAME chain.
914 * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS,
915 * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new
918 if (t
->answer_rcode
!= DNS_RCODE_NXDOMAIN
)
921 r
= dns_transaction_has_positive_answer(t
, NULL
);
925 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
929 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
) {
936 assert(t
->scope
->manager
);
938 if (t
->state
!= DNS_TRANSACTION_PENDING
)
941 /* Note that this call might invalidate the query. Callers
942 * should hence not attempt to access the query or transaction
943 * after calling this function. */
945 log_debug("Processing incoming packet on transaction %" PRIu16
" (rcode=%s).",
946 t
->id
, dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
948 switch (t
->scope
->protocol
) {
950 case DNS_PROTOCOL_LLMNR
:
951 /* For LLMNR we will not accept any packets from other interfaces */
953 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
956 if (p
->family
!= t
->scope
->family
)
959 /* Tentative packets are not full responses but still
960 * useful for identifying uniqueness conflicts during
962 if (DNS_PACKET_LLMNR_T(p
)) {
963 dns_transaction_tentative(t
, p
);
969 case DNS_PROTOCOL_MDNS
:
970 /* For mDNS we will not accept any packets from other interfaces */
972 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
975 if (p
->family
!= t
->scope
->family
)
980 case DNS_PROTOCOL_DNS
:
981 /* Note that we do not need to verify the
982 * addresses/port numbers of incoming traffic, as we
983 * invoked connect() on our UDP socket in which case
984 * the kernel already does the needed verification for
989 assert_not_reached("Invalid DNS protocol.");
992 if (t
->received
!= p
) {
993 dns_packet_unref(t
->received
);
994 t
->received
= dns_packet_ref(p
);
997 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
999 if (p
->ipproto
== IPPROTO_TCP
) {
1000 if (DNS_PACKET_TC(p
)) {
1001 /* Truncated via TCP? Somebody must be fucking with us */
1002 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1006 if (DNS_PACKET_ID(p
) != t
->id
) {
1007 /* Not the reply to our query? Somebody must be fucking with us */
1008 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1013 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1015 switch (t
->scope
->protocol
) {
1017 case DNS_PROTOCOL_DNS
:
1020 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
1022 /* Request failed, immediately try again with reduced features */
1024 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
1026 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
1027 * this transaction anymore, but let's see if it might make sense to send the request
1028 * to a different DNS server instead. If not let's process the response, and accept the
1029 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
1030 * packet loss, but is not going to give us better rcodes should we actually have
1031 * managed to get them already at UDP level. */
1033 if (t
->n_picked_servers
< dns_scope_get_n_dns_servers(t
->scope
)) {
1034 /* We tried fewer servers on this transaction than we know, let's try another one then */
1035 dns_transaction_retry(t
, true);
1039 /* Give up, accept the rcode */
1040 log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
1044 /* Reduce this feature level by one and try again. */
1045 switch (t
->current_feature_level
) {
1046 case DNS_SERVER_FEATURE_LEVEL_TLS_DO
:
1047 t
->clamp_feature_level
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
;
1049 case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
+ 1:
1050 /* Skip plain TLS when TLS is not supported */
1051 t
->clamp_feature_level
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
- 1;
1054 t
->clamp_feature_level
= t
->current_feature_level
- 1;
1057 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
1058 dns_rcode_to_string(DNS_PACKET_RCODE(p
)),
1059 dns_server_feature_level_to_string(t
->clamp_feature_level
));
1061 dns_transaction_retry(t
, false /* use the same server */);
1065 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_REFUSED
) {
1066 /* This server refused our request? If so, try again, use a different server */
1067 log_debug("Server returned REFUSED, switching servers, and retrying.");
1068 dns_transaction_retry(t
, true /* pick a new server */);
1072 if (DNS_PACKET_TC(p
))
1073 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
1077 case DNS_PROTOCOL_LLMNR
:
1078 case DNS_PROTOCOL_MDNS
:
1079 dns_scope_packet_received(t
->scope
, ts
- t
->start_usec
);
1083 assert_not_reached("Invalid DNS protocol.");
1086 if (DNS_PACKET_TC(p
)) {
1088 /* Truncated packets for mDNS are not allowed. Give up immediately. */
1089 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
1090 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1094 log_debug("Reply truncated, retrying via TCP.");
1096 /* Response was truncated, let's try again with good old TCP */
1097 r
= dns_transaction_emit_tcp(t
);
1099 /* No servers found? Damn! */
1100 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1103 if (r
== -EOPNOTSUPP
) {
1104 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1105 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1109 /* On LLMNR, if we cannot connect to the host,
1110 * we immediately give up */
1111 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1114 /* On DNS, couldn't send? Try immediately again, with a new server */
1115 dns_transaction_retry(t
, true);
1121 /* After the superficial checks, actually parse the message. */
1122 r
= dns_packet_extract(p
);
1124 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1129 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1130 * rcode and subsequently downgraded the protocol */
1132 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1133 t
->clamp_feature_level
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1134 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level
);
1136 /* Report that the OPT RR was missing */
1138 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1140 /* Report that we successfully received a packet */
1141 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, p
->size
);
1144 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1145 r
= dns_transaction_maybe_restart(t
);
1148 if (r
> 0) /* Transaction got restarted... */
1151 if (IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1153 /* When dealing with protocols other than mDNS only consider responses with
1154 * equivalent query section to the request. For mDNS this check doesn't make
1155 * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT
1156 * contain any questions in the Question Section". */
1157 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1158 r
= dns_packet_is_reply_for(p
, t
->key
);
1162 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1167 /* Install the answer as answer to the transaction */
1168 dns_answer_unref(t
->answer
);
1169 t
->answer
= dns_answer_ref(p
->answer
);
1170 t
->answer_rcode
= DNS_PACKET_RCODE(p
);
1171 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1172 t
->answer_authenticated
= false;
1174 r
= dns_transaction_fix_rcode(t
);
1178 /* Block GC while starting requests for additional DNSSEC RRs */
1180 r
= dns_transaction_request_dnssec_keys(t
);
1183 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1184 if (!dns_transaction_gc(t
))
1187 /* Requesting additional keys might have resulted in
1188 * this transaction to fail, since the auxiliary
1189 * request failed for some reason. If so, we are not
1190 * in pending state anymore, and we should exit
1192 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1197 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1198 t
->state
= DNS_TRANSACTION_VALIDATING
;
1199 dns_transaction_close_connection(t
);
1200 dns_transaction_stop_timeout(t
);
1205 dns_transaction_process_dnssec(t
);
1209 t
->answer_errno
= -r
;
1210 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1213 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1214 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1215 DnsTransaction
*t
= userdata
;
1221 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1222 if (ERRNO_IS_DISCONNECT(-r
)) {
1225 /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next
1226 * recvmsg(). Treat this like a lost packet. */
1228 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1229 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &usec
) >= 0);
1230 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
);
1232 dns_transaction_retry(t
, true);
1236 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1237 t
->answer_errno
= -r
;
1241 r
= dns_packet_validate_reply(p
);
1243 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1247 log_debug("Received inappropriate DNS packet as response, ignoring.");
1251 if (DNS_PACKET_ID(p
) != t
->id
) {
1252 log_debug("Received packet with incorrect transaction ID, ignoring.");
1256 dns_transaction_process_reply(t
, p
);
1260 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1265 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1267 r
= dns_transaction_pick_server(t
);
1271 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
|| DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
))
1272 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1274 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(t
->key
->type
))
1277 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1280 dns_transaction_close_connection(t
);
1282 fd
= dns_scope_socket_udp(t
->scope
, t
->server
, 53);
1286 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1292 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1296 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1300 dns_transaction_close_connection(t
);
1302 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->sent
);
1306 dns_transaction_reset_answer(t
);
1311 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1312 DnsTransaction
*t
= userdata
;
1317 if (!t
->initial_jitter_scheduled
|| t
->initial_jitter_elapsed
) {
1318 /* Timeout reached? Increase the timeout for the server used */
1319 switch (t
->scope
->protocol
) {
1321 case DNS_PROTOCOL_DNS
:
1323 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
);
1326 case DNS_PROTOCOL_LLMNR
:
1327 case DNS_PROTOCOL_MDNS
:
1328 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1332 assert_not_reached("Invalid DNS protocol.");
1335 if (t
->initial_jitter_scheduled
)
1336 t
->initial_jitter_elapsed
= true;
1339 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1341 dns_transaction_retry(t
, true);
1345 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1349 switch (t
->scope
->protocol
) {
1351 case DNS_PROTOCOL_DNS
:
1353 /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly
1354 * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that
1357 return TRANSACTION_TCP_TIMEOUT_USEC
;
1359 return DNS_TIMEOUT_USEC
;
1361 case DNS_PROTOCOL_MDNS
:
1362 assert(t
->n_attempts
> 0);
1364 return MDNS_PROBING_INTERVAL_USEC
;
1366 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1368 case DNS_PROTOCOL_LLMNR
:
1369 return t
->scope
->resend_timeout
;
1372 assert_not_reached("Invalid DNS protocol.");
1376 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1381 dns_transaction_stop_timeout(t
);
1383 r
= dns_scope_network_good(t
->scope
);
1387 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1391 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1392 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1396 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1397 /* If we already tried via a stream, then we don't
1398 * retry on LLMNR. See RFC 4795, Section 2.7. */
1399 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1406 dns_transaction_reset_answer(t
);
1407 dns_transaction_flush_dnssec_transactions(t
);
1409 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1410 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1411 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, t
->key
, &t
->answer
);
1415 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1416 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1417 t
->answer_authenticated
= true;
1418 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1422 if (dns_name_is_root(dns_resource_key_name(t
->key
)) &&
1423 t
->key
->type
== DNS_TYPE_DS
) {
1425 /* Hmm, this is a request for the root DS? A
1426 * DS RR doesn't exist in the root zone, and
1427 * if our trust anchor didn't know it either,
1428 * this means we cannot do any DNSSEC logic
1431 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1432 /* We are in downgrade mode. In this
1433 * case, synthesize an unsigned empty
1434 * response, so that the any lookup
1435 * depending on this one can continue
1436 * assuming there was no DS, and hence
1437 * the root zone was unsigned. */
1439 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1440 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1441 t
->answer_authenticated
= false;
1442 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1444 /* If we are not in downgrade mode,
1445 * then fail the lookup, because we
1446 * cannot reasonably answer it. There
1447 * might be DS RRs, but we don't know
1448 * them, and the DNS server won't tell
1449 * them to us (and even if it would,
1450 * we couldn't validate and trust them. */
1451 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1457 /* Check the zone, but only if this transaction is not used
1458 * for probing or verifying a zone item. */
1459 if (set_isempty(t
->notify_zone_items
)) {
1461 r
= dns_zone_lookup(&t
->scope
->zone
, t
->key
, dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1465 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1466 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1467 t
->answer_authenticated
= true;
1468 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1473 /* Check the cache, but only if this transaction is not used
1474 * for probing or verifying a zone item. */
1475 if (set_isempty(t
->notify_zone_items
)) {
1477 /* Before trying the cache, let's make sure we figured out a
1478 * server to use. Should this cause a change of server this
1479 * might flush the cache. */
1480 (void) dns_scope_get_dns_server(t
->scope
);
1482 /* Let's then prune all outdated entries */
1483 dns_cache_prune(&t
->scope
->cache
);
1485 r
= dns_cache_lookup(&t
->scope
->cache
, t
->key
, t
->clamp_ttl
, &t
->answer_rcode
, &t
->answer
, &t
->answer_authenticated
);
1489 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1490 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1491 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1493 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1501 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1503 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1504 bool add_known_answers
= false;
1505 DnsTransaction
*other
;
1507 DnsResourceKey
*tkey
;
1508 _cleanup_set_free_ Set
*keys
= NULL
;
1510 unsigned nscount
= 0;
1515 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1517 /* Discard any previously prepared packet, so we can start over and coalesce again */
1518 t
->sent
= dns_packet_unref(t
->sent
);
1520 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1524 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1530 if (dns_key_is_shared(t
->key
))
1531 add_known_answers
= true;
1533 if (t
->key
->type
== DNS_TYPE_ANY
) {
1534 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1538 r
= set_put(keys
, t
->key
);
1544 * For mDNS, we want to coalesce as many open queries in pending transactions into one single
1545 * query packet on the wire as possible. To achieve that, we iterate through all pending transactions
1546 * in our current scope, and see whether their timing contraints allow them to be sent.
1549 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1551 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1553 /* Skip ourselves */
1557 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1560 if (other
->next_attempt_after
> ts
)
1563 if (qdcount
>= UINT16_MAX
)
1566 r
= dns_packet_append_key(p
, other
->key
, 0, NULL
);
1569 * If we can't stuff more questions into the packet, just give up.
1570 * One of the 'other' transactions will fire later and take care of the rest.
1578 r
= dns_transaction_prepare(other
, ts
);
1582 ts
+= transaction_get_resend_timeout(other
);
1584 r
= sd_event_add_time(
1585 other
->scope
->manager
->event
,
1586 &other
->timeout_event_source
,
1587 clock_boottime_or_monotonic(),
1589 on_transaction_timeout
, other
);
1593 (void) sd_event_source_set_description(other
->timeout_event_source
, "dns-transaction-timeout");
1595 other
->state
= DNS_TRANSACTION_PENDING
;
1596 other
->next_attempt_after
= ts
;
1600 if (dns_key_is_shared(other
->key
))
1601 add_known_answers
= true;
1603 if (other
->key
->type
== DNS_TYPE_ANY
) {
1604 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1608 r
= set_put(keys
, other
->key
);
1614 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1616 /* Append known answer section if we're asking for any shared record */
1617 if (add_known_answers
) {
1618 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
);
1623 SET_FOREACH(tkey
, keys
, i
) {
1624 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1627 r
= dns_zone_lookup(&t
->scope
->zone
, tkey
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1631 r
= dns_packet_append_answer(p
, answer
);
1635 nscount
+= dns_answer_size(answer
);
1637 DNS_PACKET_HEADER(p
)->nscount
= htobe16(nscount
);
1639 t
->sent
= TAKE_PTR(p
);
1644 static int dns_transaction_make_packet(DnsTransaction
*t
) {
1645 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1650 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
1651 return dns_transaction_make_packet_mdns(t
);
1656 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, t
->scope
->dnssec_mode
!= DNSSEC_NO
);
1660 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1664 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
1665 DNS_PACKET_HEADER(p
)->id
= t
->id
;
1667 t
->sent
= TAKE_PTR(p
);
1672 int dns_transaction_go(DnsTransaction
*t
) {
1675 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1679 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished
1682 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1684 r
= dns_transaction_prepare(t
, ts
);
1688 log_debug("Transaction %" PRIu16
" for <%s> scope %s on %s/%s.",
1690 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
1691 dns_protocol_to_string(t
->scope
->protocol
),
1692 t
->scope
->link
? t
->scope
->link
->name
: "*",
1693 af_to_name_short(t
->scope
->family
));
1695 if (!t
->initial_jitter_scheduled
&&
1696 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1697 usec_t jitter
, accuracy
;
1699 /* RFC 4795 Section 2.7 suggests all queries should be
1700 * delayed by a random time from 0 to JITTER_INTERVAL. */
1702 t
->initial_jitter_scheduled
= true;
1704 random_bytes(&jitter
, sizeof(jitter
));
1706 switch (t
->scope
->protocol
) {
1708 case DNS_PROTOCOL_LLMNR
:
1709 jitter
%= LLMNR_JITTER_INTERVAL_USEC
;
1710 accuracy
= LLMNR_JITTER_INTERVAL_USEC
;
1713 case DNS_PROTOCOL_MDNS
:
1714 jitter
%= MDNS_JITTER_RANGE_USEC
;
1715 jitter
+= MDNS_JITTER_MIN_USEC
;
1716 accuracy
= MDNS_JITTER_RANGE_USEC
;
1719 assert_not_reached("bad protocol");
1722 r
= sd_event_add_time(
1723 t
->scope
->manager
->event
,
1724 &t
->timeout_event_source
,
1725 clock_boottime_or_monotonic(),
1726 ts
+ jitter
, accuracy
,
1727 on_transaction_timeout
, t
);
1731 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1734 t
->next_attempt_after
= ts
;
1735 t
->state
= DNS_TRANSACTION_PENDING
;
1737 log_debug("Delaying %s transaction for " USEC_FMT
"us.", dns_protocol_to_string(t
->scope
->protocol
), jitter
);
1741 /* Otherwise, we need to ask the network */
1742 r
= dns_transaction_make_packet(t
);
1746 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
1747 (dns_name_endswith(dns_resource_key_name(t
->key
), "in-addr.arpa") > 0 ||
1748 dns_name_endswith(dns_resource_key_name(t
->key
), "ip6.arpa") > 0)) {
1750 /* RFC 4795, Section 2.4. says reverse lookups shall
1751 * always be made via TCP on LLMNR */
1752 r
= dns_transaction_emit_tcp(t
);
1754 /* Try via UDP, and if that fails due to large size or lack of
1755 * support try via TCP */
1756 r
= dns_transaction_emit_udp(t
);
1758 log_debug("Sending query via TCP since it is too large.");
1759 else if (r
== -EAGAIN
)
1760 log_debug("Sending query via TCP since UDP isn't supported.");
1761 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
))
1762 r
= dns_transaction_emit_tcp(t
);
1766 /* No servers to send this to? */
1767 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1770 if (r
== -EOPNOTSUPP
) {
1771 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1772 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1775 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_DISCONNECT(-r
)) {
1776 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
1777 * answer this request with this protocol. */
1778 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
1782 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1785 /* Couldn't send? Try immediately again, with a new server */
1786 dns_scope_next_dns_server(t
->scope
);
1788 return dns_transaction_go(t
);
1791 ts
+= transaction_get_resend_timeout(t
);
1793 r
= sd_event_add_time(
1794 t
->scope
->manager
->event
,
1795 &t
->timeout_event_source
,
1796 clock_boottime_or_monotonic(),
1798 on_transaction_timeout
, t
);
1802 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1804 t
->state
= DNS_TRANSACTION_PENDING
;
1805 t
->next_attempt_after
= ts
;
1810 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
1818 /* Try to find cyclic dependencies between transaction objects */
1823 SET_FOREACH(n
, aux
->dnssec_transactions
, i
) {
1824 r
= dns_transaction_find_cyclic(t
, n
);
1832 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
1833 DnsTransaction
*aux
;
1840 aux
= dns_scope_find_transaction(t
->scope
, key
, true);
1842 r
= dns_transaction_new(&aux
, t
->scope
, key
);
1846 if (set_contains(t
->dnssec_transactions
, aux
)) {
1851 r
= dns_transaction_find_cyclic(t
, aux
);
1855 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
1857 log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
1859 dns_resource_key_to_string(t
->key
, s
, sizeof s
),
1861 dns_resource_key_to_string(aux
->key
, saux
, sizeof saux
));
1867 r
= set_ensure_allocated(&t
->dnssec_transactions
, NULL
);
1871 r
= set_ensure_allocated(&aux
->notify_transactions
, NULL
);
1875 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
1879 r
= set_put(t
->dnssec_transactions
, aux
);
1883 r
= set_put(aux
->notify_transactions
, t
);
1885 (void) set_remove(t
->dnssec_transactions
, aux
);
1893 dns_transaction_gc(aux
);
1897 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
1898 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
1899 DnsTransaction
*aux
;
1905 /* Try to get the data from the trust anchor */
1906 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
1910 r
= dns_answer_extend(&t
->validated_keys
, a
);
1917 /* This didn't work, ask for it via the network/cache then. */
1918 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
1919 if (r
== -ELOOP
) /* This would result in a cyclic dependency */
1924 if (aux
->state
== DNS_TRANSACTION_NULL
) {
1925 r
= dns_transaction_go(aux
);
1933 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
1938 /* Check whether the specified name is in the NTA
1939 * database, either in the global one, or the link-local
1942 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
1946 if (!t
->scope
->link
)
1949 return set_contains(t
->scope
->link
->dnssec_negative_trust_anchors
, name
);
1952 static int dns_transaction_has_unsigned_negative_answer(DnsTransaction
*t
) {
1957 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
1958 * RRs to prove it */
1960 r
= dns_transaction_has_positive_answer(t
, NULL
);
1966 /* Is this key explicitly listed as a negative trust anchor?
1967 * If so, it's nothing we need to care about */
1968 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
1974 /* The answer does not contain any RRs that match to the
1975 * question. If so, let's see if there are any NSEC/NSEC3 RRs
1976 * included. If not, the answer is unsigned. */
1978 r
= dns_answer_contains_nsec_or_nsec3(t
->answer
);
1987 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
1993 /* Check if the specified RR is the "primary" response,
1994 * i.e. either matches the question precisely or is a
1995 * CNAME/DNAME for it. */
1997 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
2001 return dns_resource_key_match_cname_or_dname(t
->key
, rr
->key
, NULL
);
2004 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
2007 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
2008 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
2010 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2013 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
2014 * be supported, hence return true. */
2018 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
2019 * the server is known to support currently, as the transaction feature level might be lower than what the
2020 * server actually supports, since we might have downgraded this transaction's feature level because we got a
2021 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
2023 return dns_server_dnssec_supported(t
->server
);
2026 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
2032 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
2034 if (!dns_transaction_dnssec_supported(t
))
2037 SET_FOREACH(dt
, t
->dnssec_transactions
, i
)
2038 if (!dns_transaction_dnssec_supported(dt
))
2044 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
2045 DnsResourceRecord
*rr
;
2052 * Retrieve all auxiliary RRs for the answer we got, so that
2053 * we can verify signatures or prove that RRs are rightfully
2054 * unsigned. Specifically:
2056 * - For RRSIG we get the matching DNSKEY
2057 * - For DNSKEY we get the matching DS
2058 * - For unsigned SOA/NS we get the matching DS
2059 * - For unsigned CNAME/DNAME/DS we get the parent SOA RR
2060 * - For other unsigned RRs we get the matching SOA RR
2061 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
2062 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR
2063 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR
2066 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2068 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
2069 return 0; /* We only need to validate stuff from the network */
2070 if (!dns_transaction_dnssec_supported(t
))
2071 return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */
2073 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2075 if (dns_type_is_pseudo(rr
->key
->type
))
2078 /* If this RR is in the negative trust anchor, we don't need to validate it. */
2079 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2085 switch (rr
->key
->type
) {
2087 case DNS_TYPE_RRSIG
: {
2088 /* For each RRSIG we request the matching DNSKEY */
2089 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
2091 /* If this RRSIG is about a DNSKEY RR and the
2092 * signer is the same as the owner, then we
2093 * already have the DNSKEY, and we don't have
2094 * to look for more. */
2095 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
2096 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
2103 /* If the signer is not a parent of our
2104 * original query, then this is about an
2105 * auxiliary RRset, but not anything we asked
2106 * for. In this case we aren't interested,
2107 * because we don't want to request additional
2108 * RRs for stuff we didn't really ask for, and
2109 * also to avoid request loops, where
2110 * additional RRs from one transaction result
2111 * in another transaction whose additonal RRs
2112 * point back to the original transaction, and
2114 r
= dns_name_endswith(dns_resource_key_name(t
->key
), rr
->rrsig
.signer
);
2120 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2124 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2125 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2126 r
= dns_transaction_request_dnssec_rr(t
, dnskey
);
2132 case DNS_TYPE_DNSKEY
: {
2133 /* For each DNSKEY we request the matching DS */
2134 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2136 /* If the DNSKEY we are looking at is not for
2137 * zone we are interested in, nor any of its
2138 * parents, we aren't interested, and don't
2139 * request it. After all, we don't want to end
2140 * up in request loops, and want to keep
2141 * additional traffic down. */
2143 r
= dns_name_endswith(dns_resource_key_name(t
->key
), dns_resource_key_name(rr
->key
));
2149 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2153 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2154 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2155 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2164 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2166 /* For an unsigned SOA or NS, try to acquire
2167 * the matching DS RR, as we are at a zone cut
2168 * then, and whether a DS exists tells us
2169 * whether the zone is signed. Do so only if
2170 * this RR matches our original question,
2173 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
2177 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2178 * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry?
2179 * If so, we need to validate it, too. */
2181 r
= dns_answer_match_key(t
->answer
, t
->key
, NULL
);
2184 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2189 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2195 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2199 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2200 t
->id
, dns_resource_key_name(rr
->key
));
2201 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2209 case DNS_TYPE_CNAME
:
2210 case DNS_TYPE_DNAME
: {
2211 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2214 /* CNAMEs and DNAMEs cannot be located at a
2215 * zone apex, hence ask for the parent SOA for
2216 * unsigned CNAME/DNAME RRs, maybe that's the
2217 * apex. But do all that only if this is
2218 * actually a response to our original
2221 * Similar for DS RRs, which are signed when
2222 * the parent SOA is signed. */
2224 r
= dns_transaction_is_primary_response(t
, rr
);
2230 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2236 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2242 name
= dns_resource_key_name(rr
->key
);
2243 r
= dns_name_parent(&name
);
2249 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2253 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2254 t
->id
, dns_resource_key_name(rr
->key
));
2255 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2263 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2265 /* For other unsigned RRsets (including
2266 * NSEC/NSEC3!), look for proof the zone is
2267 * unsigned, by requesting the SOA RR of the
2268 * zone. However, do so only if they are
2269 * directly relevant to our original
2272 r
= dns_transaction_is_primary_response(t
, rr
);
2278 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2284 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, dns_resource_key_name(rr
->key
));
2288 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2289 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2290 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2297 /* Above, we requested everything necessary to validate what
2298 * we got. Now, let's request what we need to validate what we
2301 r
= dns_transaction_has_unsigned_negative_answer(t
);
2308 name
= dns_resource_key_name(t
->key
);
2310 /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this
2311 * could also be used as indication that we are not at a zone apex, but in real world setups there are
2312 * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even
2313 * though they have further children. If this was a DS request, then it's signed when the parent zone
2314 * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR,
2315 * to see if that is signed. */
2317 if (t
->key
->type
== DNS_TYPE_DS
) {
2318 r
= dns_name_parent(&name
);
2320 type
= DNS_TYPE_SOA
;
2321 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned empty DS response).",
2322 t
->id
, dns_resource_key_name(t
->key
));
2326 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
)) {
2329 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned empty SOA/NS response).",
2330 t
->id
, dns_resource_key_name(t
->key
));
2333 type
= DNS_TYPE_SOA
;
2334 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned empty non-SOA/NS/DS response).",
2335 t
->id
, dns_resource_key_name(t
->key
));
2339 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2341 soa
= dns_resource_key_new(t
->key
->class, type
, name
);
2345 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2351 return dns_transaction_dnssec_is_live(t
);
2354 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2358 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2359 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2360 the state is VALIDATING however, we should check if we are complete now. */
2362 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2363 dns_transaction_process_dnssec(t
);
2366 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2367 DnsResourceRecord
*rr
;
2372 /* Add all DNSKEY RRs from the answer that are validated by DS
2373 * RRs from the list of validated keys to the list of
2374 * validated keys. */
2376 DNS_ANSWER_FOREACH_IFINDEX(rr
, ifindex
, t
->answer
) {
2378 r
= dnssec_verify_dnskey_by_ds_search(rr
, t
->validated_keys
);
2384 /* If so, the DNSKEY is validated too. */
2385 r
= dns_answer_add_extend(&t
->validated_keys
, rr
, ifindex
, DNS_ANSWER_AUTHENTICATED
);
2393 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2399 /* Checks if the RR we are looking for must be signed with an
2400 * RRSIG. This is used for positive responses. */
2402 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2405 if (dns_type_is_pseudo(rr
->key
->type
))
2408 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2414 switch (rr
->key
->type
) {
2416 case DNS_TYPE_RRSIG
:
2417 /* RRSIGs are the signatures themselves, they need no signing. */
2425 /* For SOA or NS RRs we look for a matching DS transaction */
2427 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2429 if (dt
->key
->class != rr
->key
->class)
2431 if (dt
->key
->type
!= DNS_TYPE_DS
)
2434 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2440 /* We found a DS transactions for the SOA/NS
2441 * RRs we are looking at. If it discovered signed DS
2442 * RRs, then we need to be signed, too. */
2444 if (!dt
->answer_authenticated
)
2447 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2450 /* We found nothing that proves this is safe to leave
2451 * this unauthenticated, hence ask inist on
2452 * authentication. */
2457 case DNS_TYPE_CNAME
:
2458 case DNS_TYPE_DNAME
: {
2459 const char *parent
= NULL
;
2464 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA.
2466 * DS RRs are signed if the parent is signed, hence also look at the parent SOA
2469 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2471 if (dt
->key
->class != rr
->key
->class)
2473 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2477 parent
= dns_resource_key_name(rr
->key
);
2478 r
= dns_name_parent(&parent
);
2482 if (rr
->key
->type
== DNS_TYPE_DS
)
2485 /* A CNAME/DNAME without a parent? That's sooo weird. */
2486 log_debug("Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2491 r
= dns_name_equal(dns_resource_key_name(dt
->key
), parent
);
2497 return t
->answer_authenticated
;
2507 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */
2509 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2511 if (dt
->key
->class != rr
->key
->class)
2513 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2516 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2522 /* We found the transaction that was supposed to find
2523 * the SOA RR for us. It was successful, but found no
2524 * RR for us. This means we are not at a zone cut. In
2525 * this case, we require authentication if the SOA
2526 * lookup was authenticated too. */
2527 return t
->answer_authenticated
;
2534 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
2540 /* If DNSSEC downgrade mode is on, checks whether the
2541 * specified RR is one level below a TLD we have proven not to
2542 * exist. In such a case we assume that this is a private
2543 * domain, and permit it.
2545 * This detects cases like the Fritz!Box router networks. Each
2546 * Fritz!Box router serves a private "fritz.box" zone, in the
2547 * non-existing TLD "box". Requests for the "fritz.box" domain
2548 * are served by the router itself, while requests for the
2549 * "box" domain will result in NXDOMAIN.
2551 * Note that this logic is unable to detect cases where a
2552 * router serves a private DNS zone directly under
2553 * non-existing TLD. In such a case we cannot detect whether
2554 * the TLD is supposed to exist or not, as all requests we
2555 * make for it will be answered by the router's zone, and not
2556 * by the root zone. */
2560 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
2561 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
2563 tld
= dns_resource_key_name(key
);
2564 r
= dns_name_parent(&tld
);
2568 return false; /* Already the root domain */
2570 if (!dns_name_is_single_label(tld
))
2573 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2575 if (dt
->key
->class != key
->class)
2578 r
= dns_name_equal(dns_resource_key_name(dt
->key
), tld
);
2584 /* We found an auxiliary lookup we did for the TLD. If
2585 * that returned with NXDOMAIN, we know the TLD didn't
2586 * exist, and hence this might be a private zone. */
2588 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
2594 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
2595 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2604 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
2605 * this negative reply */
2607 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2610 if (dns_type_is_pseudo(t
->key
->type
))
2613 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
2619 r
= dns_transaction_in_private_tld(t
, t
->key
);
2623 /* The lookup is from a TLD that is proven not to
2624 * exist, and we are in downgrade mode, hence ignore
2625 * that fact that we didn't get any NSEC RRs. */
2627 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
2628 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
2632 name
= dns_resource_key_name(t
->key
);
2634 if (t
->key
->type
== DNS_TYPE_DS
) {
2636 /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed,
2637 * hence check the parent SOA in this case. */
2639 r
= dns_name_parent(&name
);
2645 type
= DNS_TYPE_SOA
;
2647 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
))
2648 /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */
2651 /* For all other negative replies, check for the SOA lookup */
2652 type
= DNS_TYPE_SOA
;
2654 /* For all other RRs we check the SOA on the same level to see
2655 * if it's signed. */
2657 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2659 if (dt
->key
->class != t
->key
->class)
2661 if (dt
->key
->type
!= type
)
2664 r
= dns_name_equal(dns_resource_key_name(dt
->key
), name
);
2670 return dt
->answer_authenticated
;
2673 /* If in doubt, require NSEC/NSEC3 */
2677 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2678 DnsResourceRecord
*rrsig
;
2682 /* Checks whether any of the DNSKEYs used for the RRSIGs for
2683 * the specified RRset is authenticated (i.e. has a matching
2686 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2692 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
2696 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
2702 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2704 if (dt
->key
->class != rr
->key
->class)
2707 if (dt
->key
->type
== DNS_TYPE_DNSKEY
) {
2709 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2715 /* OK, we found an auxiliary DNSKEY
2716 * lookup. If that lookup is
2717 * authenticated, report this. */
2719 if (dt
->answer_authenticated
)
2724 } else if (dt
->key
->type
== DNS_TYPE_DS
) {
2726 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2732 /* OK, we found an auxiliary DS
2733 * lookup. If that lookup is
2734 * authenticated and non-zero, we
2737 if (!dt
->answer_authenticated
)
2740 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2745 return found
? false : -ENXIO
;
2748 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2752 /* We know that the root domain is signed, hence if it appears
2753 * not to be signed, there's a problem with the DNS server */
2755 return rr
->key
->class == DNS_CLASS_IN
&&
2756 dns_name_is_root(dns_resource_key_name(rr
->key
));
2759 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
2760 DnsResourceRecord
*rr
;
2765 /* Maybe warn the user that we encountered a revoked DNSKEY
2766 * for a key from our trust anchor. Note that we don't care
2767 * whether the DNSKEY can be authenticated or not. It's
2768 * sufficient if it is self-signed. */
2770 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2771 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
2779 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
2785 /* Removes all DNSKEY/DS objects from t->validated_keys that
2786 * our trust anchors database considers revoked. */
2789 DnsResourceRecord
*rr
;
2793 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
2794 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
2798 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
2812 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
2819 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
2821 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2823 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
2826 if (!dt
->answer_authenticated
)
2829 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
2838 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
2839 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
2840 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
2843 static int dnssec_validate_records(
2847 DnsAnswer
**validated
) {
2849 DnsResourceRecord
*rr
;
2852 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
2854 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2855 DnsResourceRecord
*rrsig
= NULL
;
2856 DnssecResult result
;
2858 switch (rr
->key
->type
) {
2859 case DNS_TYPE_RRSIG
:
2862 case DNS_TYPE_DNSKEY
:
2863 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
2864 if (phase
== DNSSEC_PHASE_NSEC
)
2869 case DNS_TYPE_NSEC3
:
2872 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
2873 if (phase
== DNSSEC_PHASE_DNSKEY
)
2878 /* We validate all other RRs only in the ALL phases */
2879 if (phase
!= DNSSEC_PHASE_ALL
)
2883 r
= dnssec_verify_rrset_search(t
->answer
, rr
->key
, t
->validated_keys
, USEC_INFINITY
, &result
, &rrsig
);
2887 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
2889 if (result
== DNSSEC_VALIDATED
) {
2891 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
2892 /* If we just validated a DNSKEY RRset, then let's add these keys to
2893 * the set of validated keys for this transaction. */
2895 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
);
2899 /* Some of the DNSKEYs we just added might already have been revoked,
2900 * remove them again in that case. */
2901 r
= dns_transaction_invalidate_revoked_keys(t
);
2906 /* Add the validated RRset to the new list of validated
2907 * RRsets, and remove it from the unvalidated RRsets.
2908 * We mark the RRset as authenticated and cacheable. */
2909 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
);
2913 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
2915 /* Exit the loop, we dropped something from the answer, start from the beginning */
2919 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
2920 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
2921 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
2922 if (phase
!= DNSSEC_PHASE_ALL
)
2925 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
2926 bool authenticated
= false;
2929 /* This RRset validated, but as a wildcard. This means we need
2930 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
2932 /* First step, determine the source of synthesis */
2933 r
= dns_resource_record_source(rrsig
, &source
);
2937 r
= dnssec_test_positive_wildcard(*validated
,
2938 dns_resource_key_name(rr
->key
),
2940 rrsig
->rrsig
.signer
,
2943 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
2945 result
= DNSSEC_INVALID
;
2947 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
,
2948 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0);
2952 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
2954 /* Exit the loop, we dropped something from the answer, start from the beginning */
2959 if (result
== DNSSEC_NO_SIGNATURE
) {
2960 r
= dns_transaction_requires_rrsig(t
, rr
);
2964 /* Data does not require signing. In that case, just copy it over,
2965 * but remember that this is by no means authenticated. */
2966 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2970 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2974 r
= dns_transaction_known_signed(t
, rr
);
2978 /* This is an RR we know has to be signed. If it isn't this means
2979 * the server is not attaching RRSIGs, hence complain. */
2981 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
2983 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
2985 /* Downgrading is OK? If so, just consider the information unsigned */
2987 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2991 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2995 /* Otherwise, fail */
2996 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3000 r
= dns_transaction_in_private_tld(t
, rr
->key
);
3004 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
3006 /* The data is from a TLD that is proven not to exist, and we are in downgrade
3007 * mode, hence ignore the fact that this was not signed. */
3009 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
3010 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
3012 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
3016 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3023 DNSSEC_SIGNATURE_EXPIRED
,
3024 DNSSEC_UNSUPPORTED_ALGORITHM
)) {
3026 r
= dns_transaction_dnskey_authenticated(t
, rr
);
3027 if (r
< 0 && r
!= -ENXIO
)
3030 /* The DNSKEY transaction was not authenticated, this means there's
3031 * no DS for this, which means it's OK if no keys are found for this signature. */
3033 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
3037 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3042 r
= dns_transaction_is_primary_response(t
, rr
);
3046 /* Look for a matching DNAME for this CNAME */
3047 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
3051 /* Also look among the stuff we already validated */
3052 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
3060 DNSSEC_SIGNATURE_EXPIRED
,
3061 DNSSEC_NO_SIGNATURE
))
3062 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
3063 else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */
3064 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
3066 /* This is a primary response to our question, and it failed validation.
3068 t
->answer_dnssec_result
= result
;
3072 /* This is a primary response, but we do have a DNAME RR
3073 * in the RR that can replay this CNAME, hence rely on
3074 * that, and we can remove the CNAME in favour of it. */
3077 /* This is just some auxiliary data. Just remove the RRset and continue. */
3078 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
3082 /* We dropped something from the answer, start from the beginning. */
3086 return 2; /* Finito. */
3089 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
3090 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
3092 DnsAnswerFlags flags
;
3094 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3098 /* We have now collected all DS and DNSKEY RRs in
3099 * t->validated_keys, let's see which RRs we can now
3100 * authenticate with that. */
3102 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3105 /* Already validated */
3106 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3109 /* Our own stuff needs no validation */
3110 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3111 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3112 t
->answer_authenticated
= true;
3116 /* Cached stuff is not affected by validation. */
3117 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3120 if (!dns_transaction_dnssec_supported_full(t
)) {
3121 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3122 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3123 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3127 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3129 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
3131 /* First, see if this response contains any revoked trust
3132 * anchors we care about */
3133 r
= dns_transaction_check_revoked_trust_anchors(t
);
3137 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3138 r
= dns_transaction_copy_validated(t
);
3142 /* Second, see if there are DNSKEYs we already know a
3143 * validated DS for. */
3144 r
= dns_transaction_validate_dnskey_by_ds(t
);
3148 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3149 * anchor says are revoked. After all we might have marked
3150 * some keys revoked above, but they might still be lingering
3151 * in our validated_keys list. */
3152 r
= dns_transaction_invalidate_revoked_keys(t
);
3156 phase
= DNSSEC_PHASE_DNSKEY
;
3158 bool have_nsec
= false;
3160 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &validated
);
3164 /* Try again as long as we managed to achieve something */
3168 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3169 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3170 phase
= DNSSEC_PHASE_NSEC
;
3174 if (phase
!= DNSSEC_PHASE_ALL
) {
3175 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3176 * Note that in this third phase we start to remove RRs we couldn't validate. */
3177 phase
= DNSSEC_PHASE_ALL
;
3185 dns_answer_unref(t
->answer
);
3186 t
->answer
= TAKE_PTR(validated
);
3188 /* At this point the answer only contains validated
3189 * RRsets. Now, let's see if it actually answers the question
3190 * we asked. If so, great! If it doesn't, then see if
3191 * NSEC/NSEC3 can prove this. */
3192 r
= dns_transaction_has_positive_answer(t
, &flags
);
3194 /* Yes, it answers the question! */
3196 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3197 /* The answer is fully authenticated, yay. */
3198 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3199 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3200 t
->answer_authenticated
= true;
3202 /* The answer is not fully authenticated. */
3203 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3204 t
->answer_authenticated
= false;
3207 } else if (r
== 0) {
3208 DnssecNsecResult nr
;
3209 bool authenticated
= false;
3211 /* Bummer! Let's check NSEC/NSEC3 */
3212 r
= dnssec_nsec_test(t
->answer
, t
->key
, &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3218 case DNSSEC_NSEC_NXDOMAIN
:
3219 /* NSEC proves the domain doesn't exist. Very good. */
3220 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3221 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3222 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3223 t
->answer_authenticated
= authenticated
;
3225 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3228 case DNSSEC_NSEC_NODATA
:
3229 /* NSEC proves that there's no data here, very good. */
3230 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3231 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3232 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3233 t
->answer_authenticated
= authenticated
;
3235 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3238 case DNSSEC_NSEC_OPTOUT
:
3239 /* NSEC3 says the data might not be signed */
3240 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3241 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3242 t
->answer_authenticated
= false;
3244 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3247 case DNSSEC_NSEC_NO_RR
:
3248 /* No NSEC data? Bummer! */
3250 r
= dns_transaction_requires_nsec(t
);
3254 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3255 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3257 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3258 t
->answer_authenticated
= false;
3259 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3264 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3265 /* We don't know the NSEC3 algorithm used? */
3266 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3267 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, t
->key
);
3270 case DNSSEC_NSEC_FOUND
:
3271 case DNSSEC_NSEC_CNAME
:
3272 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3273 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3274 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3278 assert_not_reached("Unexpected NSEC result.");
3285 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3286 [DNS_TRANSACTION_NULL
] = "null",
3287 [DNS_TRANSACTION_PENDING
] = "pending",
3288 [DNS_TRANSACTION_VALIDATING
] = "validating",
3289 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3290 [DNS_TRANSACTION_SUCCESS
] = "success",
3291 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3292 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3293 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3294 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3295 [DNS_TRANSACTION_ERRNO
] = "errno",
3296 [DNS_TRANSACTION_ABORTED
] = "aborted",
3297 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3298 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3299 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3300 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3301 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3303 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3305 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3306 [DNS_TRANSACTION_NETWORK
] = "network",
3307 [DNS_TRANSACTION_CACHE
] = "cache",
3308 [DNS_TRANSACTION_ZONE
] = "zone",
3309 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3311 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);