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)", t
->id
, dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
947 switch (t
->scope
->protocol
) {
949 case DNS_PROTOCOL_LLMNR
:
950 /* For LLMNR we will not accept any packets from other interfaces */
952 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
955 if (p
->family
!= t
->scope
->family
)
958 /* Tentative packets are not full responses but still
959 * useful for identifying uniqueness conflicts during
961 if (DNS_PACKET_LLMNR_T(p
)) {
962 dns_transaction_tentative(t
, p
);
968 case DNS_PROTOCOL_MDNS
:
969 /* For mDNS we will not accept any packets from other interfaces */
971 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
974 if (p
->family
!= t
->scope
->family
)
979 case DNS_PROTOCOL_DNS
:
980 /* Note that we do not need to verify the
981 * addresses/port numbers of incoming traffic, as we
982 * invoked connect() on our UDP socket in which case
983 * the kernel already does the needed verification for
988 assert_not_reached("Invalid DNS protocol.");
991 if (t
->received
!= p
) {
992 dns_packet_unref(t
->received
);
993 t
->received
= dns_packet_ref(p
);
996 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
998 if (p
->ipproto
== IPPROTO_TCP
) {
999 if (DNS_PACKET_TC(p
)) {
1000 /* Truncated via TCP? Somebody must be fucking with us */
1001 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1005 if (DNS_PACKET_ID(p
) != t
->id
) {
1006 /* Not the reply to our query? Somebody must be fucking with us */
1007 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1012 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1014 switch (t
->scope
->protocol
) {
1016 case DNS_PROTOCOL_DNS
:
1019 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
1021 /* Request failed, immediately try again with reduced features */
1023 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
1025 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
1026 * this transaction anymore, but let's see if it might make sense to send the request
1027 * to a different DNS server instead. If not let's process the response, and accept the
1028 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
1029 * packet loss, but is not going to give us better rcodes should we actually have
1030 * managed to get them already at UDP level. */
1032 if (t
->n_picked_servers
< dns_scope_get_n_dns_servers(t
->scope
)) {
1033 /* We tried fewer servers on this transaction than we know, let's try another one then */
1034 dns_transaction_retry(t
, true);
1038 /* Give up, accept the rcode */
1039 log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
1043 /* Reduce this feature level by one and try again. */
1044 switch (t
->current_feature_level
) {
1045 case DNS_SERVER_FEATURE_LEVEL_TLS_DO
:
1046 t
->clamp_feature_level
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
;
1048 case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
+ 1:
1049 /* Skip plain TLS when TLS is not supported */
1050 t
->clamp_feature_level
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
- 1;
1053 t
->clamp_feature_level
= t
->current_feature_level
- 1;
1056 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
1057 dns_rcode_to_string(DNS_PACKET_RCODE(p
)),
1058 dns_server_feature_level_to_string(t
->clamp_feature_level
));
1060 dns_transaction_retry(t
, false /* use the same server */);
1064 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_REFUSED
) {
1065 /* This server refused our request? If so, try again, use a different server */
1066 log_debug("Server returned REFUSED, switching servers, and retrying.");
1067 dns_transaction_retry(t
, true /* pick a new server */);
1071 if (DNS_PACKET_TC(p
))
1072 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
1076 case DNS_PROTOCOL_LLMNR
:
1077 case DNS_PROTOCOL_MDNS
:
1078 dns_scope_packet_received(t
->scope
, ts
- t
->start_usec
);
1082 assert_not_reached("Invalid DNS protocol.");
1085 if (DNS_PACKET_TC(p
)) {
1087 /* Truncated packets for mDNS are not allowed. Give up immediately. */
1088 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
1089 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1093 log_debug("Reply truncated, retrying via TCP.");
1095 /* Response was truncated, let's try again with good old TCP */
1096 r
= dns_transaction_emit_tcp(t
);
1098 /* No servers found? Damn! */
1099 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1102 if (r
== -EOPNOTSUPP
) {
1103 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1104 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1108 /* On LLMNR, if we cannot connect to the host,
1109 * we immediately give up */
1110 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1113 /* On DNS, couldn't send? Try immediately again, with a new server */
1114 dns_transaction_retry(t
, true);
1120 /* After the superficial checks, actually parse the message. */
1121 r
= dns_packet_extract(p
);
1123 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1128 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1129 * rcode and subsequently downgraded the protocol */
1131 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1132 t
->clamp_feature_level
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1133 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level
);
1135 /* Report that the OPT RR was missing */
1137 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1139 /* Report that we successfully received a packet */
1140 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, p
->size
);
1143 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1144 r
= dns_transaction_maybe_restart(t
);
1147 if (r
> 0) /* Transaction got restarted... */
1150 if (IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1152 /* When dealing with protocols other than mDNS only consider responses with
1153 * equivalent query section to the request. For mDNS this check doesn't make
1154 * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT
1155 * contain any questions in the Question Section". */
1156 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1157 r
= dns_packet_is_reply_for(p
, t
->key
);
1161 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1166 /* Install the answer as answer to the transaction */
1167 dns_answer_unref(t
->answer
);
1168 t
->answer
= dns_answer_ref(p
->answer
);
1169 t
->answer_rcode
= DNS_PACKET_RCODE(p
);
1170 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1171 t
->answer_authenticated
= false;
1173 r
= dns_transaction_fix_rcode(t
);
1177 /* Block GC while starting requests for additional DNSSEC RRs */
1179 r
= dns_transaction_request_dnssec_keys(t
);
1182 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1183 if (!dns_transaction_gc(t
))
1186 /* Requesting additional keys might have resulted in
1187 * this transaction to fail, since the auxiliary
1188 * request failed for some reason. If so, we are not
1189 * in pending state anymore, and we should exit
1191 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1196 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1197 t
->state
= DNS_TRANSACTION_VALIDATING
;
1198 dns_transaction_close_connection(t
);
1199 dns_transaction_stop_timeout(t
);
1204 dns_transaction_process_dnssec(t
);
1208 t
->answer_errno
= -r
;
1209 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1212 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1213 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1214 DnsTransaction
*t
= userdata
;
1220 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1221 if (ERRNO_IS_DISCONNECT(-r
)) {
1224 /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next
1225 * recvmsg(). Treat this like a lost packet. */
1227 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1228 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &usec
) >= 0);
1229 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
);
1231 dns_transaction_retry(t
, true);
1235 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1236 t
->answer_errno
= -r
;
1240 r
= dns_packet_validate_reply(p
);
1242 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1246 log_debug("Received inappropriate DNS packet as response, ignoring.");
1250 if (DNS_PACKET_ID(p
) != t
->id
) {
1251 log_debug("Received packet with incorrect transaction ID, ignoring.");
1255 dns_transaction_process_reply(t
, p
);
1259 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1264 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1266 r
= dns_transaction_pick_server(t
);
1270 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
|| DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
))
1271 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1273 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(t
->key
->type
))
1276 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1279 dns_transaction_close_connection(t
);
1281 fd
= dns_scope_socket_udp(t
->scope
, t
->server
, 53);
1285 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1291 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1295 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1299 dns_transaction_close_connection(t
);
1301 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->sent
);
1305 dns_transaction_reset_answer(t
);
1310 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1311 DnsTransaction
*t
= userdata
;
1316 if (!t
->initial_jitter_scheduled
|| t
->initial_jitter_elapsed
) {
1317 /* Timeout reached? Increase the timeout for the server used */
1318 switch (t
->scope
->protocol
) {
1320 case DNS_PROTOCOL_DNS
:
1322 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
);
1325 case DNS_PROTOCOL_LLMNR
:
1326 case DNS_PROTOCOL_MDNS
:
1327 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1331 assert_not_reached("Invalid DNS protocol.");
1334 if (t
->initial_jitter_scheduled
)
1335 t
->initial_jitter_elapsed
= true;
1338 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1340 dns_transaction_retry(t
, true);
1344 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1348 switch (t
->scope
->protocol
) {
1350 case DNS_PROTOCOL_DNS
:
1352 /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly
1353 * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that
1356 return TRANSACTION_TCP_TIMEOUT_USEC
;
1358 return DNS_TIMEOUT_USEC
;
1360 case DNS_PROTOCOL_MDNS
:
1361 assert(t
->n_attempts
> 0);
1363 return MDNS_PROBING_INTERVAL_USEC
;
1365 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1367 case DNS_PROTOCOL_LLMNR
:
1368 return t
->scope
->resend_timeout
;
1371 assert_not_reached("Invalid DNS protocol.");
1375 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1380 dns_transaction_stop_timeout(t
);
1382 r
= dns_scope_network_good(t
->scope
);
1386 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1390 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1391 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1395 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1396 /* If we already tried via a stream, then we don't
1397 * retry on LLMNR. See RFC 4795, Section 2.7. */
1398 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1405 dns_transaction_reset_answer(t
);
1406 dns_transaction_flush_dnssec_transactions(t
);
1408 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1409 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1410 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, t
->key
, &t
->answer
);
1414 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1415 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1416 t
->answer_authenticated
= true;
1417 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1421 if (dns_name_is_root(dns_resource_key_name(t
->key
)) &&
1422 t
->key
->type
== DNS_TYPE_DS
) {
1424 /* Hmm, this is a request for the root DS? A
1425 * DS RR doesn't exist in the root zone, and
1426 * if our trust anchor didn't know it either,
1427 * this means we cannot do any DNSSEC logic
1430 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1431 /* We are in downgrade mode. In this
1432 * case, synthesize an unsigned empty
1433 * response, so that the any lookup
1434 * depending on this one can continue
1435 * assuming there was no DS, and hence
1436 * the root zone was unsigned. */
1438 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1439 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1440 t
->answer_authenticated
= false;
1441 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1443 /* If we are not in downgrade mode,
1444 * then fail the lookup, because we
1445 * cannot reasonably answer it. There
1446 * might be DS RRs, but we don't know
1447 * them, and the DNS server won't tell
1448 * them to us (and even if it would,
1449 * we couldn't validate and trust them. */
1450 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1456 /* Check the zone, but only if this transaction is not used
1457 * for probing or verifying a zone item. */
1458 if (set_isempty(t
->notify_zone_items
)) {
1460 r
= dns_zone_lookup(&t
->scope
->zone
, t
->key
, dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1464 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1465 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1466 t
->answer_authenticated
= true;
1467 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1472 /* Check the cache, but only if this transaction is not used
1473 * for probing or verifying a zone item. */
1474 if (set_isempty(t
->notify_zone_items
)) {
1476 /* Before trying the cache, let's make sure we figured out a
1477 * server to use. Should this cause a change of server this
1478 * might flush the cache. */
1479 (void) dns_scope_get_dns_server(t
->scope
);
1481 /* Let's then prune all outdated entries */
1482 dns_cache_prune(&t
->scope
->cache
);
1484 r
= dns_cache_lookup(&t
->scope
->cache
, t
->key
, t
->clamp_ttl
, &t
->answer_rcode
, &t
->answer
, &t
->answer_authenticated
);
1488 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1489 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1490 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1492 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1500 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1502 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1503 bool add_known_answers
= false;
1504 DnsTransaction
*other
;
1506 DnsResourceKey
*tkey
;
1507 _cleanup_set_free_ Set
*keys
= NULL
;
1509 unsigned nscount
= 0;
1514 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1516 /* Discard any previously prepared packet, so we can start over and coalesce again */
1517 t
->sent
= dns_packet_unref(t
->sent
);
1519 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1523 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1529 if (dns_key_is_shared(t
->key
))
1530 add_known_answers
= true;
1532 if (t
->key
->type
== DNS_TYPE_ANY
) {
1533 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1537 r
= set_put(keys
, t
->key
);
1543 * For mDNS, we want to coalesce as many open queries in pending transactions into one single
1544 * query packet on the wire as possible. To achieve that, we iterate through all pending transactions
1545 * in our current scope, and see whether their timing contraints allow them to be sent.
1548 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1550 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1552 /* Skip ourselves */
1556 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1559 if (other
->next_attempt_after
> ts
)
1562 if (qdcount
>= UINT16_MAX
)
1565 r
= dns_packet_append_key(p
, other
->key
, 0, NULL
);
1568 * If we can't stuff more questions into the packet, just give up.
1569 * One of the 'other' transactions will fire later and take care of the rest.
1577 r
= dns_transaction_prepare(other
, ts
);
1581 ts
+= transaction_get_resend_timeout(other
);
1583 r
= sd_event_add_time(
1584 other
->scope
->manager
->event
,
1585 &other
->timeout_event_source
,
1586 clock_boottime_or_monotonic(),
1588 on_transaction_timeout
, other
);
1592 (void) sd_event_source_set_description(other
->timeout_event_source
, "dns-transaction-timeout");
1594 other
->state
= DNS_TRANSACTION_PENDING
;
1595 other
->next_attempt_after
= ts
;
1599 if (dns_key_is_shared(other
->key
))
1600 add_known_answers
= true;
1602 if (other
->key
->type
== DNS_TYPE_ANY
) {
1603 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1607 r
= set_put(keys
, other
->key
);
1613 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1615 /* Append known answer section if we're asking for any shared record */
1616 if (add_known_answers
) {
1617 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
);
1622 SET_FOREACH(tkey
, keys
, i
) {
1623 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1626 r
= dns_zone_lookup(&t
->scope
->zone
, tkey
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1630 r
= dns_packet_append_answer(p
, answer
);
1634 nscount
+= dns_answer_size(answer
);
1636 DNS_PACKET_HEADER(p
)->nscount
= htobe16(nscount
);
1638 t
->sent
= TAKE_PTR(p
);
1643 static int dns_transaction_make_packet(DnsTransaction
*t
) {
1644 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1649 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
1650 return dns_transaction_make_packet_mdns(t
);
1655 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, t
->scope
->dnssec_mode
!= DNSSEC_NO
);
1659 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1663 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
1664 DNS_PACKET_HEADER(p
)->id
= t
->id
;
1666 t
->sent
= TAKE_PTR(p
);
1671 int dns_transaction_go(DnsTransaction
*t
) {
1674 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1678 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished
1681 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1683 r
= dns_transaction_prepare(t
, ts
);
1687 log_debug("Transaction %" PRIu16
" for <%s> scope %s on %s/%s.",
1689 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
1690 dns_protocol_to_string(t
->scope
->protocol
),
1691 t
->scope
->link
? t
->scope
->link
->name
: "*",
1692 af_to_name_short(t
->scope
->family
));
1694 if (!t
->initial_jitter_scheduled
&&
1695 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1696 usec_t jitter
, accuracy
;
1698 /* RFC 4795 Section 2.7 suggests all queries should be
1699 * delayed by a random time from 0 to JITTER_INTERVAL. */
1701 t
->initial_jitter_scheduled
= true;
1703 random_bytes(&jitter
, sizeof(jitter
));
1705 switch (t
->scope
->protocol
) {
1707 case DNS_PROTOCOL_LLMNR
:
1708 jitter
%= LLMNR_JITTER_INTERVAL_USEC
;
1709 accuracy
= LLMNR_JITTER_INTERVAL_USEC
;
1712 case DNS_PROTOCOL_MDNS
:
1713 jitter
%= MDNS_JITTER_RANGE_USEC
;
1714 jitter
+= MDNS_JITTER_MIN_USEC
;
1715 accuracy
= MDNS_JITTER_RANGE_USEC
;
1718 assert_not_reached("bad protocol");
1721 r
= sd_event_add_time(
1722 t
->scope
->manager
->event
,
1723 &t
->timeout_event_source
,
1724 clock_boottime_or_monotonic(),
1725 ts
+ jitter
, accuracy
,
1726 on_transaction_timeout
, t
);
1730 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1733 t
->next_attempt_after
= ts
;
1734 t
->state
= DNS_TRANSACTION_PENDING
;
1736 log_debug("Delaying %s transaction for " USEC_FMT
"us.", dns_protocol_to_string(t
->scope
->protocol
), jitter
);
1740 /* Otherwise, we need to ask the network */
1741 r
= dns_transaction_make_packet(t
);
1745 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
1746 (dns_name_endswith(dns_resource_key_name(t
->key
), "in-addr.arpa") > 0 ||
1747 dns_name_endswith(dns_resource_key_name(t
->key
), "ip6.arpa") > 0)) {
1749 /* RFC 4795, Section 2.4. says reverse lookups shall
1750 * always be made via TCP on LLMNR */
1751 r
= dns_transaction_emit_tcp(t
);
1753 /* Try via UDP, and if that fails due to large size or lack of
1754 * support try via TCP */
1755 r
= dns_transaction_emit_udp(t
);
1757 log_debug("Sending query via TCP since it is too large.");
1758 else if (r
== -EAGAIN
)
1759 log_debug("Sending query via TCP since UDP isn't supported.");
1760 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
))
1761 r
= dns_transaction_emit_tcp(t
);
1765 /* No servers to send this to? */
1766 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1769 if (r
== -EOPNOTSUPP
) {
1770 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1771 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1774 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_DISCONNECT(-r
)) {
1775 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
1776 * answer this request with this protocol. */
1777 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
1781 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1784 /* Couldn't send? Try immediately again, with a new server */
1785 dns_scope_next_dns_server(t
->scope
);
1787 return dns_transaction_go(t
);
1790 ts
+= transaction_get_resend_timeout(t
);
1792 r
= sd_event_add_time(
1793 t
->scope
->manager
->event
,
1794 &t
->timeout_event_source
,
1795 clock_boottime_or_monotonic(),
1797 on_transaction_timeout
, t
);
1801 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1803 t
->state
= DNS_TRANSACTION_PENDING
;
1804 t
->next_attempt_after
= ts
;
1809 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
1817 /* Try to find cyclic dependencies between transaction objects */
1822 SET_FOREACH(n
, aux
->dnssec_transactions
, i
) {
1823 r
= dns_transaction_find_cyclic(t
, n
);
1831 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
1832 DnsTransaction
*aux
;
1839 aux
= dns_scope_find_transaction(t
->scope
, key
, true);
1841 r
= dns_transaction_new(&aux
, t
->scope
, key
);
1845 if (set_contains(t
->dnssec_transactions
, aux
)) {
1850 r
= dns_transaction_find_cyclic(t
, aux
);
1854 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
1856 log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
1858 dns_resource_key_to_string(t
->key
, s
, sizeof s
),
1860 dns_resource_key_to_string(aux
->key
, saux
, sizeof saux
));
1866 r
= set_ensure_allocated(&t
->dnssec_transactions
, NULL
);
1870 r
= set_ensure_allocated(&aux
->notify_transactions
, NULL
);
1874 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
1878 r
= set_put(t
->dnssec_transactions
, aux
);
1882 r
= set_put(aux
->notify_transactions
, t
);
1884 (void) set_remove(t
->dnssec_transactions
, aux
);
1892 dns_transaction_gc(aux
);
1896 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
1897 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
1898 DnsTransaction
*aux
;
1904 /* Try to get the data from the trust anchor */
1905 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
1909 r
= dns_answer_extend(&t
->validated_keys
, a
);
1916 /* This didn't work, ask for it via the network/cache then. */
1917 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
1918 if (r
== -ELOOP
) /* This would result in a cyclic dependency */
1923 if (aux
->state
== DNS_TRANSACTION_NULL
) {
1924 r
= dns_transaction_go(aux
);
1932 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
1937 /* Check whether the specified name is in the NTA
1938 * database, either in the global one, or the link-local
1941 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
1945 if (!t
->scope
->link
)
1948 return set_contains(t
->scope
->link
->dnssec_negative_trust_anchors
, name
);
1951 static int dns_transaction_has_unsigned_negative_answer(DnsTransaction
*t
) {
1956 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
1957 * RRs to prove it */
1959 r
= dns_transaction_has_positive_answer(t
, NULL
);
1965 /* Is this key explicitly listed as a negative trust anchor?
1966 * If so, it's nothing we need to care about */
1967 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
1973 /* The answer does not contain any RRs that match to the
1974 * question. If so, let's see if there are any NSEC/NSEC3 RRs
1975 * included. If not, the answer is unsigned. */
1977 r
= dns_answer_contains_nsec_or_nsec3(t
->answer
);
1986 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
1992 /* Check if the specified RR is the "primary" response,
1993 * i.e. either matches the question precisely or is a
1994 * CNAME/DNAME for it. */
1996 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
2000 return dns_resource_key_match_cname_or_dname(t
->key
, rr
->key
, NULL
);
2003 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
2006 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
2007 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
2009 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2012 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
2013 * be supported, hence return true. */
2017 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
2018 * the server is known to support currently, as the transaction feature level might be lower than what the
2019 * server actually supports, since we might have downgraded this transaction's feature level because we got a
2020 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
2022 return dns_server_dnssec_supported(t
->server
);
2025 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
2031 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
2033 if (!dns_transaction_dnssec_supported(t
))
2036 SET_FOREACH(dt
, t
->dnssec_transactions
, i
)
2037 if (!dns_transaction_dnssec_supported(dt
))
2043 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
2044 DnsResourceRecord
*rr
;
2051 * Retrieve all auxiliary RRs for the answer we got, so that
2052 * we can verify signatures or prove that RRs are rightfully
2053 * unsigned. Specifically:
2055 * - For RRSIG we get the matching DNSKEY
2056 * - For DNSKEY we get the matching DS
2057 * - For unsigned SOA/NS we get the matching DS
2058 * - For unsigned CNAME/DNAME/DS we get the parent SOA RR
2059 * - For other unsigned RRs we get the matching SOA RR
2060 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
2061 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR
2062 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR
2065 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2067 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
2068 return 0; /* We only need to validate stuff from the network */
2069 if (!dns_transaction_dnssec_supported(t
))
2070 return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */
2072 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2074 if (dns_type_is_pseudo(rr
->key
->type
))
2077 /* If this RR is in the negative trust anchor, we don't need to validate it. */
2078 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2084 switch (rr
->key
->type
) {
2086 case DNS_TYPE_RRSIG
: {
2087 /* For each RRSIG we request the matching DNSKEY */
2088 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
2090 /* If this RRSIG is about a DNSKEY RR and the
2091 * signer is the same as the owner, then we
2092 * already have the DNSKEY, and we don't have
2093 * to look for more. */
2094 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
2095 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
2102 /* If the signer is not a parent of our
2103 * original query, then this is about an
2104 * auxiliary RRset, but not anything we asked
2105 * for. In this case we aren't interested,
2106 * because we don't want to request additional
2107 * RRs for stuff we didn't really ask for, and
2108 * also to avoid request loops, where
2109 * additional RRs from one transaction result
2110 * in another transaction whose additonal RRs
2111 * point back to the original transaction, and
2113 r
= dns_name_endswith(dns_resource_key_name(t
->key
), rr
->rrsig
.signer
);
2119 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2123 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2124 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2125 r
= dns_transaction_request_dnssec_rr(t
, dnskey
);
2131 case DNS_TYPE_DNSKEY
: {
2132 /* For each DNSKEY we request the matching DS */
2133 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2135 /* If the DNSKEY we are looking at is not for
2136 * zone we are interested in, nor any of its
2137 * parents, we aren't interested, and don't
2138 * request it. After all, we don't want to end
2139 * up in request loops, and want to keep
2140 * additional traffic down. */
2142 r
= dns_name_endswith(dns_resource_key_name(t
->key
), dns_resource_key_name(rr
->key
));
2148 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2152 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2153 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2154 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2163 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2165 /* For an unsigned SOA or NS, try to acquire
2166 * the matching DS RR, as we are at a zone cut
2167 * then, and whether a DS exists tells us
2168 * whether the zone is signed. Do so only if
2169 * this RR matches our original question,
2172 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
2176 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2177 * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry?
2178 * If so, we need to validate it, too. */
2180 r
= dns_answer_match_key(t
->answer
, t
->key
, NULL
);
2183 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2188 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2194 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2198 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2199 t
->id
, dns_resource_key_name(rr
->key
));
2200 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2208 case DNS_TYPE_CNAME
:
2209 case DNS_TYPE_DNAME
: {
2210 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2213 /* CNAMEs and DNAMEs cannot be located at a
2214 * zone apex, hence ask for the parent SOA for
2215 * unsigned CNAME/DNAME RRs, maybe that's the
2216 * apex. But do all that only if this is
2217 * actually a response to our original
2220 * Similar for DS RRs, which are signed when
2221 * the parent SOA is signed. */
2223 r
= dns_transaction_is_primary_response(t
, rr
);
2229 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2235 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2241 name
= dns_resource_key_name(rr
->key
);
2242 r
= dns_name_parent(&name
);
2248 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2252 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2253 t
->id
, dns_resource_key_name(rr
->key
));
2254 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2262 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2264 /* For other unsigned RRsets (including
2265 * NSEC/NSEC3!), look for proof the zone is
2266 * unsigned, by requesting the SOA RR of the
2267 * zone. However, do so only if they are
2268 * directly relevant to our original
2271 r
= dns_transaction_is_primary_response(t
, rr
);
2277 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2283 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, dns_resource_key_name(rr
->key
));
2287 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2288 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2289 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2296 /* Above, we requested everything necessary to validate what
2297 * we got. Now, let's request what we need to validate what we
2300 r
= dns_transaction_has_unsigned_negative_answer(t
);
2307 name
= dns_resource_key_name(t
->key
);
2309 /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this
2310 * could also be used as indication that we are not at a zone apex, but in real world setups there are
2311 * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even
2312 * though they have further children. If this was a DS request, then it's signed when the parent zone
2313 * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR,
2314 * to see if that is signed. */
2316 if (t
->key
->type
== DNS_TYPE_DS
) {
2317 r
= dns_name_parent(&name
);
2319 type
= DNS_TYPE_SOA
;
2320 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned empty DS response).",
2321 t
->id
, dns_resource_key_name(t
->key
));
2325 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
)) {
2328 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned empty SOA/NS response).",
2329 t
->id
, dns_resource_key_name(t
->key
));
2332 type
= DNS_TYPE_SOA
;
2333 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned empty non-SOA/NS/DS response).",
2334 t
->id
, dns_resource_key_name(t
->key
));
2338 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2340 soa
= dns_resource_key_new(t
->key
->class, type
, name
);
2344 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2350 return dns_transaction_dnssec_is_live(t
);
2353 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2357 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2358 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2359 the state is VALIDATING however, we should check if we are complete now. */
2361 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2362 dns_transaction_process_dnssec(t
);
2365 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2366 DnsResourceRecord
*rr
;
2371 /* Add all DNSKEY RRs from the answer that are validated by DS
2372 * RRs from the list of validated keys to the list of
2373 * validated keys. */
2375 DNS_ANSWER_FOREACH_IFINDEX(rr
, ifindex
, t
->answer
) {
2377 r
= dnssec_verify_dnskey_by_ds_search(rr
, t
->validated_keys
);
2383 /* If so, the DNSKEY is validated too. */
2384 r
= dns_answer_add_extend(&t
->validated_keys
, rr
, ifindex
, DNS_ANSWER_AUTHENTICATED
);
2392 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2398 /* Checks if the RR we are looking for must be signed with an
2399 * RRSIG. This is used for positive responses. */
2401 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2404 if (dns_type_is_pseudo(rr
->key
->type
))
2407 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2413 switch (rr
->key
->type
) {
2415 case DNS_TYPE_RRSIG
:
2416 /* RRSIGs are the signatures themselves, they need no signing. */
2424 /* For SOA or NS RRs we look for a matching DS transaction */
2426 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2428 if (dt
->key
->class != rr
->key
->class)
2430 if (dt
->key
->type
!= DNS_TYPE_DS
)
2433 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2439 /* We found a DS transactions for the SOA/NS
2440 * RRs we are looking at. If it discovered signed DS
2441 * RRs, then we need to be signed, too. */
2443 if (!dt
->answer_authenticated
)
2446 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2449 /* We found nothing that proves this is safe to leave
2450 * this unauthenticated, hence ask inist on
2451 * authentication. */
2456 case DNS_TYPE_CNAME
:
2457 case DNS_TYPE_DNAME
: {
2458 const char *parent
= NULL
;
2463 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA.
2465 * DS RRs are signed if the parent is signed, hence also look at the parent SOA
2468 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2470 if (dt
->key
->class != rr
->key
->class)
2472 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2476 parent
= dns_resource_key_name(rr
->key
);
2477 r
= dns_name_parent(&parent
);
2481 if (rr
->key
->type
== DNS_TYPE_DS
)
2484 /* A CNAME/DNAME without a parent? That's sooo weird. */
2485 log_debug("Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2490 r
= dns_name_equal(dns_resource_key_name(dt
->key
), parent
);
2496 return t
->answer_authenticated
;
2506 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */
2508 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2510 if (dt
->key
->class != rr
->key
->class)
2512 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2515 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2521 /* We found the transaction that was supposed to find
2522 * the SOA RR for us. It was successful, but found no
2523 * RR for us. This means we are not at a zone cut. In
2524 * this case, we require authentication if the SOA
2525 * lookup was authenticated too. */
2526 return t
->answer_authenticated
;
2533 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
2539 /* If DNSSEC downgrade mode is on, checks whether the
2540 * specified RR is one level below a TLD we have proven not to
2541 * exist. In such a case we assume that this is a private
2542 * domain, and permit it.
2544 * This detects cases like the Fritz!Box router networks. Each
2545 * Fritz!Box router serves a private "fritz.box" zone, in the
2546 * non-existing TLD "box". Requests for the "fritz.box" domain
2547 * are served by the router itself, while requests for the
2548 * "box" domain will result in NXDOMAIN.
2550 * Note that this logic is unable to detect cases where a
2551 * router serves a private DNS zone directly under
2552 * non-existing TLD. In such a case we cannot detect whether
2553 * the TLD is supposed to exist or not, as all requests we
2554 * make for it will be answered by the router's zone, and not
2555 * by the root zone. */
2559 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
2560 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
2562 tld
= dns_resource_key_name(key
);
2563 r
= dns_name_parent(&tld
);
2567 return false; /* Already the root domain */
2569 if (!dns_name_is_single_label(tld
))
2572 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2574 if (dt
->key
->class != key
->class)
2577 r
= dns_name_equal(dns_resource_key_name(dt
->key
), tld
);
2583 /* We found an auxiliary lookup we did for the TLD. If
2584 * that returned with NXDOMAIN, we know the TLD didn't
2585 * exist, and hence this might be a private zone. */
2587 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
2593 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
2594 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2603 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
2604 * this negative reply */
2606 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2609 if (dns_type_is_pseudo(t
->key
->type
))
2612 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
2618 r
= dns_transaction_in_private_tld(t
, t
->key
);
2622 /* The lookup is from a TLD that is proven not to
2623 * exist, and we are in downgrade mode, hence ignore
2624 * that fact that we didn't get any NSEC RRs. */
2626 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
2627 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
2631 name
= dns_resource_key_name(t
->key
);
2633 if (t
->key
->type
== DNS_TYPE_DS
) {
2635 /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed,
2636 * hence check the parent SOA in this case. */
2638 r
= dns_name_parent(&name
);
2644 type
= DNS_TYPE_SOA
;
2646 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
))
2647 /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */
2650 /* For all other negative replies, check for the SOA lookup */
2651 type
= DNS_TYPE_SOA
;
2653 /* For all other RRs we check the SOA on the same level to see
2654 * if it's signed. */
2656 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2658 if (dt
->key
->class != t
->key
->class)
2660 if (dt
->key
->type
!= type
)
2663 r
= dns_name_equal(dns_resource_key_name(dt
->key
), name
);
2669 return dt
->answer_authenticated
;
2672 /* If in doubt, require NSEC/NSEC3 */
2676 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2677 DnsResourceRecord
*rrsig
;
2681 /* Checks whether any of the DNSKEYs used for the RRSIGs for
2682 * the specified RRset is authenticated (i.e. has a matching
2685 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2691 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
2695 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
2701 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2703 if (dt
->key
->class != rr
->key
->class)
2706 if (dt
->key
->type
== DNS_TYPE_DNSKEY
) {
2708 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2714 /* OK, we found an auxiliary DNSKEY
2715 * lookup. If that lookup is
2716 * authenticated, report this. */
2718 if (dt
->answer_authenticated
)
2723 } else if (dt
->key
->type
== DNS_TYPE_DS
) {
2725 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2731 /* OK, we found an auxiliary DS
2732 * lookup. If that lookup is
2733 * authenticated and non-zero, we
2736 if (!dt
->answer_authenticated
)
2739 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2744 return found
? false : -ENXIO
;
2747 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2751 /* We know that the root domain is signed, hence if it appears
2752 * not to be signed, there's a problem with the DNS server */
2754 return rr
->key
->class == DNS_CLASS_IN
&&
2755 dns_name_is_root(dns_resource_key_name(rr
->key
));
2758 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
2759 DnsResourceRecord
*rr
;
2764 /* Maybe warn the user that we encountered a revoked DNSKEY
2765 * for a key from our trust anchor. Note that we don't care
2766 * whether the DNSKEY can be authenticated or not. It's
2767 * sufficient if it is self-signed. */
2769 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2770 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
2778 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
2784 /* Removes all DNSKEY/DS objects from t->validated_keys that
2785 * our trust anchors database considers revoked. */
2788 DnsResourceRecord
*rr
;
2792 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
2793 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
2797 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
2811 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
2818 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
2820 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2822 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
2825 if (!dt
->answer_authenticated
)
2828 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
2837 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
2838 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
2839 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
2842 static int dnssec_validate_records(
2846 DnsAnswer
**validated
) {
2848 DnsResourceRecord
*rr
;
2851 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
2853 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2854 DnsResourceRecord
*rrsig
= NULL
;
2855 DnssecResult result
;
2857 switch (rr
->key
->type
) {
2858 case DNS_TYPE_RRSIG
:
2861 case DNS_TYPE_DNSKEY
:
2862 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
2863 if (phase
== DNSSEC_PHASE_NSEC
)
2868 case DNS_TYPE_NSEC3
:
2871 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
2872 if (phase
== DNSSEC_PHASE_DNSKEY
)
2877 /* We validate all other RRs only in the ALL phases */
2878 if (phase
!= DNSSEC_PHASE_ALL
)
2882 r
= dnssec_verify_rrset_search(t
->answer
, rr
->key
, t
->validated_keys
, USEC_INFINITY
, &result
, &rrsig
);
2886 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
2888 if (result
== DNSSEC_VALIDATED
) {
2890 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
2891 /* If we just validated a DNSKEY RRset, then let's add these keys to
2892 * the set of validated keys for this transaction. */
2894 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
);
2898 /* Some of the DNSKEYs we just added might already have been revoked,
2899 * remove them again in that case. */
2900 r
= dns_transaction_invalidate_revoked_keys(t
);
2905 /* Add the validated RRset to the new list of validated
2906 * RRsets, and remove it from the unvalidated RRsets.
2907 * We mark the RRset as authenticated and cacheable. */
2908 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
);
2912 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
2914 /* Exit the loop, we dropped something from the answer, start from the beginning */
2918 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
2919 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
2920 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
2921 if (phase
!= DNSSEC_PHASE_ALL
)
2924 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
2925 bool authenticated
= false;
2928 /* This RRset validated, but as a wildcard. This means we need
2929 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
2931 /* First step, determine the source of synthesis */
2932 r
= dns_resource_record_source(rrsig
, &source
);
2936 r
= dnssec_test_positive_wildcard(*validated
,
2937 dns_resource_key_name(rr
->key
),
2939 rrsig
->rrsig
.signer
,
2942 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
2944 result
= DNSSEC_INVALID
;
2946 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
,
2947 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0);
2951 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
2953 /* Exit the loop, we dropped something from the answer, start from the beginning */
2958 if (result
== DNSSEC_NO_SIGNATURE
) {
2959 r
= dns_transaction_requires_rrsig(t
, rr
);
2963 /* Data does not require signing. In that case, just copy it over,
2964 * but remember that this is by no means authenticated. */
2965 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2969 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2973 r
= dns_transaction_known_signed(t
, rr
);
2977 /* This is an RR we know has to be signed. If it isn't this means
2978 * the server is not attaching RRSIGs, hence complain. */
2980 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
2982 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
2984 /* Downgrading is OK? If so, just consider the information unsigned */
2986 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2990 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2994 /* Otherwise, fail */
2995 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
2999 r
= dns_transaction_in_private_tld(t
, rr
->key
);
3003 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
3005 /* The data is from a TLD that is proven not to exist, and we are in downgrade
3006 * mode, hence ignore the fact that this was not signed. */
3008 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
3009 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
3011 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
3015 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3022 DNSSEC_SIGNATURE_EXPIRED
,
3023 DNSSEC_UNSUPPORTED_ALGORITHM
)) {
3025 r
= dns_transaction_dnskey_authenticated(t
, rr
);
3026 if (r
< 0 && r
!= -ENXIO
)
3029 /* The DNSKEY transaction was not authenticated, this means there's
3030 * no DS for this, which means it's OK if no keys are found for this signature. */
3032 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
3036 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3041 r
= dns_transaction_is_primary_response(t
, rr
);
3045 /* Look for a matching DNAME for this CNAME */
3046 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
3050 /* Also look among the stuff we already validated */
3051 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
3059 DNSSEC_SIGNATURE_EXPIRED
,
3060 DNSSEC_NO_SIGNATURE
))
3061 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
3062 else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */
3063 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
3065 /* This is a primary response to our question, and it failed validation.
3067 t
->answer_dnssec_result
= result
;
3071 /* This is a primary response, but we do have a DNAME RR
3072 * in the RR that can replay this CNAME, hence rely on
3073 * that, and we can remove the CNAME in favour of it. */
3076 /* This is just some auxiliary data. Just remove the RRset and continue. */
3077 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
3081 /* We dropped something from the answer, start from the beginning. */
3085 return 2; /* Finito. */
3088 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
3089 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
3091 DnsAnswerFlags flags
;
3093 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3097 /* We have now collected all DS and DNSKEY RRs in
3098 * t->validated_keys, let's see which RRs we can now
3099 * authenticate with that. */
3101 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3104 /* Already validated */
3105 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3108 /* Our own stuff needs no validation */
3109 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3110 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3111 t
->answer_authenticated
= true;
3115 /* Cached stuff is not affected by validation. */
3116 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3119 if (!dns_transaction_dnssec_supported_full(t
)) {
3120 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3121 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3122 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3126 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3128 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
3130 /* First, see if this response contains any revoked trust
3131 * anchors we care about */
3132 r
= dns_transaction_check_revoked_trust_anchors(t
);
3136 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3137 r
= dns_transaction_copy_validated(t
);
3141 /* Second, see if there are DNSKEYs we already know a
3142 * validated DS for. */
3143 r
= dns_transaction_validate_dnskey_by_ds(t
);
3147 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3148 * anchor says are revoked. After all we might have marked
3149 * some keys revoked above, but they might still be lingering
3150 * in our validated_keys list. */
3151 r
= dns_transaction_invalidate_revoked_keys(t
);
3155 phase
= DNSSEC_PHASE_DNSKEY
;
3157 bool have_nsec
= false;
3159 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &validated
);
3163 /* Try again as long as we managed to achieve something */
3167 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3168 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3169 phase
= DNSSEC_PHASE_NSEC
;
3173 if (phase
!= DNSSEC_PHASE_ALL
) {
3174 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3175 * Note that in this third phase we start to remove RRs we couldn't validate. */
3176 phase
= DNSSEC_PHASE_ALL
;
3184 dns_answer_unref(t
->answer
);
3185 t
->answer
= TAKE_PTR(validated
);
3187 /* At this point the answer only contains validated
3188 * RRsets. Now, let's see if it actually answers the question
3189 * we asked. If so, great! If it doesn't, then see if
3190 * NSEC/NSEC3 can prove this. */
3191 r
= dns_transaction_has_positive_answer(t
, &flags
);
3193 /* Yes, it answers the question! */
3195 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3196 /* The answer is fully authenticated, yay. */
3197 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3198 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3199 t
->answer_authenticated
= true;
3201 /* The answer is not fully authenticated. */
3202 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3203 t
->answer_authenticated
= false;
3206 } else if (r
== 0) {
3207 DnssecNsecResult nr
;
3208 bool authenticated
= false;
3210 /* Bummer! Let's check NSEC/NSEC3 */
3211 r
= dnssec_nsec_test(t
->answer
, t
->key
, &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3217 case DNSSEC_NSEC_NXDOMAIN
:
3218 /* NSEC proves the domain doesn't exist. Very good. */
3219 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3220 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3221 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3222 t
->answer_authenticated
= authenticated
;
3224 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3227 case DNSSEC_NSEC_NODATA
:
3228 /* NSEC proves that there's no data here, very good. */
3229 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3230 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3231 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3232 t
->answer_authenticated
= authenticated
;
3234 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3237 case DNSSEC_NSEC_OPTOUT
:
3238 /* NSEC3 says the data might not be signed */
3239 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3240 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3241 t
->answer_authenticated
= false;
3243 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3246 case DNSSEC_NSEC_NO_RR
:
3247 /* No NSEC data? Bummer! */
3249 r
= dns_transaction_requires_nsec(t
);
3253 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3254 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3256 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3257 t
->answer_authenticated
= false;
3258 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3263 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3264 /* We don't know the NSEC3 algorithm used? */
3265 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3266 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, t
->key
);
3269 case DNSSEC_NSEC_FOUND
:
3270 case DNSSEC_NSEC_CNAME
:
3271 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3272 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3273 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3277 assert_not_reached("Unexpected NSEC result.");
3284 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3285 [DNS_TRANSACTION_NULL
] = "null",
3286 [DNS_TRANSACTION_PENDING
] = "pending",
3287 [DNS_TRANSACTION_VALIDATING
] = "validating",
3288 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3289 [DNS_TRANSACTION_SUCCESS
] = "success",
3290 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3291 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3292 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3293 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3294 [DNS_TRANSACTION_ERRNO
] = "errno",
3295 [DNS_TRANSACTION_ABORTED
] = "aborted",
3296 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3297 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3298 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3299 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3300 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3302 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3304 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3305 [DNS_TRANSACTION_NETWORK
] = "network",
3306 [DNS_TRANSACTION_CACHE
] = "cache",
3307 [DNS_TRANSACTION_ZONE
] = "zone",
3308 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3310 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);