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-rw-r--r--src/resolve/resolved-dns-transaction.c1399
1 files changed, 1125 insertions, 274 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 347b1683f9..5640cd1d33 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -19,6 +19,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
+#include <sd-messages.h>
+
#include "af-list.h"
#include "alloc-util.h"
#include "dns-domain.h"
@@ -29,6 +31,45 @@
#include "resolved-llmnr.h"
#include "string-table.h"
+#define TRANSACTIONS_MAX 4096
+
+static void dns_transaction_reset_answer(DnsTransaction *t) {
+ assert(t);
+
+ t->received = dns_packet_unref(t->received);
+ t->answer = dns_answer_unref(t->answer);
+ t->answer_rcode = 0;
+ t->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
+ t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
+ t->answer_authenticated = false;
+ t->answer_nsec_ttl = (uint32_t) -1;
+}
+
+static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) {
+ DnsTransaction *z;
+
+ assert(t);
+
+ while ((z = set_steal_first(t->dnssec_transactions))) {
+ set_remove(z->notify_transactions, t);
+ dns_transaction_gc(z);
+ }
+}
+
+static void dns_transaction_close_connection(DnsTransaction *t) {
+ assert(t);
+
+ t->stream = dns_stream_free(t->stream);
+ t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source);
+ t->dns_udp_fd = safe_close(t->dns_udp_fd);
+}
+
+static void dns_transaction_stop_timeout(DnsTransaction *t) {
+ assert(t);
+
+ t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
+}
+
DnsTransaction* dns_transaction_free(DnsTransaction *t) {
DnsQueryCandidate *c;
DnsZoneItem *i;
@@ -37,18 +78,15 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) {
if (!t)
return NULL;
- sd_event_source_unref(t->timeout_event_source);
+ log_debug("Freeing transaction %" PRIu16 ".", t->id);
- dns_packet_unref(t->sent);
- dns_packet_unref(t->received);
+ dns_transaction_close_connection(t);
+ dns_transaction_stop_timeout(t);
- dns_answer_unref(t->answer);
-
- sd_event_source_unref(t->dns_udp_event_source);
- safe_close(t->dns_udp_fd);
+ dns_packet_unref(t->sent);
+ dns_transaction_reset_answer(t);
dns_server_unref(t->server);
- dns_stream_free(t->stream);
if (t->scope) {
hashmap_remove_value(t->scope->transactions_by_key, t->key, t);
@@ -58,8 +96,6 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) {
hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id));
}
- dns_resource_key_unref(t->key);
-
while ((c = set_steal_first(t->notify_query_candidates)))
set_remove(c->transactions, t);
set_free(t->notify_query_candidates);
@@ -72,31 +108,49 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) {
set_remove(z->dnssec_transactions, t);
set_free(t->notify_transactions);
- while ((z = set_steal_first(t->dnssec_transactions))) {
- set_remove(z->notify_transactions, t);
- dns_transaction_gc(z);
- }
+ dns_transaction_flush_dnssec_transactions(t);
set_free(t->dnssec_transactions);
dns_answer_unref(t->validated_keys);
-
+ dns_resource_key_unref(t->key);
free(t->key_string);
+
free(t);
return NULL;
}
DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free);
-void dns_transaction_gc(DnsTransaction *t) {
+bool dns_transaction_gc(DnsTransaction *t) {
assert(t);
if (t->block_gc > 0)
- return;
+ return true;
if (set_isempty(t->notify_query_candidates) &&
set_isempty(t->notify_zone_items) &&
- set_isempty(t->notify_transactions))
+ set_isempty(t->notify_transactions)) {
dns_transaction_free(t);
+ return false;
+ }
+
+ return true;
+}
+
+static uint16_t pick_new_id(Manager *m) {
+ uint16_t new_id;
+
+ /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of
+ * transactions, and it's much lower than the space of IDs. */
+
+ assert_cc(TRANSACTIONS_MAX < 0xFFFF);
+
+ do
+ random_bytes(&new_id, sizeof(new_id));
+ while (new_id == 0 ||
+ hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id)));
+
+ return new_id;
}
int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) {
@@ -110,11 +164,16 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key)
/* Don't allow looking up invalid or pseudo RRs */
if (!dns_type_is_valid_query(key->type))
return -EINVAL;
+ if (dns_type_is_obsolete(key->type))
+ return -EOPNOTSUPP;
/* We only support the IN class */
if (key->class != DNS_CLASS_IN && key->class != DNS_CLASS_ANY)
return -EOPNOTSUPP;
+ if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX)
+ return -EBUSY;
+
r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL);
if (r < 0)
return r;
@@ -130,13 +189,11 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key)
t->dns_udp_fd = -1;
t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
t->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
+ t->answer_nsec_ttl = (uint32_t) -1;
t->key = dns_resource_key_ref(key);
+ t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID;
- /* Find a fresh, unused transaction id */
- do
- random_bytes(&t->id, sizeof(t->id));
- while (t->id == 0 ||
- hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(t->id)));
+ t->id = pick_new_id(s->manager);
r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t);
if (r < 0) {
@@ -153,6 +210,8 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key)
LIST_PREPEND(transactions_by_scope, s->transactions, t);
t->scope = s;
+ s->manager->n_transactions_total ++;
+
if (ret)
*ret = t;
@@ -161,14 +220,20 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key)
return 0;
}
-static void dns_transaction_stop(DnsTransaction *t) {
+static void dns_transaction_shuffle_id(DnsTransaction *t) {
+ uint16_t new_id;
assert(t);
- t->timeout_event_source = sd_event_source_unref(t->timeout_event_source);
- t->stream = dns_stream_free(t->stream);
+ /* Pick a new ID for this transaction. */
+
+ new_id = pick_new_id(t->scope->manager);
+ assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0);
- /* Note that we do not drop the UDP socket here, as we want to
- * reuse it to repeat the interaction. */
+ log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id);
+ t->id = new_id;
+
+ /* Make sure we generate a new packet with the new ID */
+ t->sent = dns_packet_unref(t->sent);
}
static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) {
@@ -224,6 +289,15 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
assert(t);
assert(!DNS_TRANSACTION_IS_LIVE(state));
+ if (state == DNS_TRANSACTION_DNSSEC_FAILED)
+ log_struct(LOG_NOTICE,
+ LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_FAILURE),
+ LOG_MESSAGE("DNSSEC validation failed for question %s: %s", dns_transaction_key_string(t), dnssec_result_to_string(t->answer_dnssec_result)),
+ "DNS_TRANSACTION=%" PRIu16, t->id,
+ "DNS_QUESTION=%s", dns_transaction_key_string(t),
+ "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result),
+ NULL);
+
/* Note that this call might invalidate the query. Callers
* should hence not attempt to access the query or transaction
* after calling this function. */
@@ -240,7 +314,8 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
t->state = state;
- dns_transaction_stop(t);
+ dns_transaction_close_connection(t);
+ dns_transaction_stop_timeout(t);
/* Notify all queries that are interested, but make sure the
* transaction isn't freed while we are still looking at it */
@@ -284,6 +359,62 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
dns_transaction_gc(t);
}
+static int dns_transaction_pick_server(DnsTransaction *t) {
+ DnsServer *server;
+
+ assert(t);
+ assert(t->scope->protocol == DNS_PROTOCOL_DNS);
+
+ server = dns_scope_get_dns_server(t->scope);
+ if (!server)
+ return -ESRCH;
+
+ t->current_feature_level = dns_server_possible_feature_level(server);
+
+ if (server == t->server)
+ return 0;
+
+ dns_server_unref(t->server);
+ t->server = dns_server_ref(server);
+
+ return 1;
+}
+
+static void dns_transaction_retry(DnsTransaction *t) {
+ int r;
+
+ assert(t);
+
+ log_debug("Retrying transaction %" PRIu16 ".", t->id);
+
+ /* Before we try again, switch to a new server. */
+ dns_scope_next_dns_server(t->scope);
+
+ r = dns_transaction_go(t);
+ if (r < 0)
+ dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
+}
+
+static int dns_transaction_maybe_restart(DnsTransaction *t) {
+ assert(t);
+
+ if (!t->server)
+ return 0;
+
+ if (t->current_feature_level <= dns_server_possible_feature_level(t->server))
+ return 0;
+
+ /* The server's current feature level is lower than when we sent the original query. We learnt something from
+ the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
+ restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
+ OPT RR or DO bit. One of these cases is documented here, for example:
+ https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
+
+ log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
+ dns_transaction_shuffle_id(t);
+ return dns_transaction_go(t);
+}
+
static int on_stream_complete(DnsStream *s, int error) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
DnsTransaction *t;
@@ -298,6 +429,16 @@ static int on_stream_complete(DnsStream *s, int error) {
t->stream = dns_stream_free(t->stream);
+ if (ERRNO_IS_DISCONNECT(error)) {
+ usec_t usec;
+
+ log_debug_errno(error, "Connection failure for DNS TCP stream: %m");
+ assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0);
+ dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level, usec - t->start_usec);
+
+ dns_transaction_retry(t);
+ return 0;
+ }
if (error != 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return 0;
@@ -315,32 +456,46 @@ static int on_stream_complete(DnsStream *s, int error) {
dns_transaction_process_reply(t, p);
t->block_gc--;
- /* If the response wasn't useful, then complete the transition now */
+ /* If the response wasn't useful, then complete the transition
+ * now. After all, we are the worst feature set now with TCP
+ * sockets, and there's really no point in retrying. */
if (t->state == DNS_TRANSACTION_PENDING)
dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
+ else
+ dns_transaction_gc(t);
return 0;
}
static int dns_transaction_open_tcp(DnsTransaction *t) {
- DnsServer *server = NULL;
_cleanup_close_ int fd = -1;
int r;
assert(t);
- if (t->stream)
- return 0;
+ dns_transaction_close_connection(t);
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_DNS:
- fd = dns_scope_tcp_socket(t->scope, AF_UNSPEC, NULL, 53, &server);
+ r = dns_transaction_pick_server(t);
+ if (r < 0)
+ return r;
+
+ if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type))
+ return -EOPNOTSUPP;
+
+ r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level);
+ if (r < 0)
+ return r;
+
+ fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, 53);
break;
case DNS_PROTOCOL_LLMNR:
/* When we already received a reply to this (but it was truncated), send to its sender address */
if (t->received)
- fd = dns_scope_tcp_socket(t->scope, t->received->family, &t->received->sender, t->received->sender_port, NULL);
+ fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port);
else {
union in_addr_union address;
int family = AF_UNSPEC;
@@ -357,7 +512,7 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
if (family != t->scope->family)
return -ESRCH;
- fd = dns_scope_tcp_socket(t->scope, family, &address, LLMNR_PORT, NULL);
+ fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT);
}
break;
@@ -372,7 +527,6 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
r = dns_stream_new(t->scope->manager, &t->stream, t->scope->protocol, fd);
if (r < 0)
return r;
-
fd = -1;
r = dns_stream_write_packet(t->stream, t->sent);
@@ -381,11 +535,6 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
return r;
}
- dns_server_unref(t->server);
- t->server = dns_server_ref(server);
- t->received = dns_packet_unref(t->received);
- t->answer = dns_answer_unref(t->answer);
- t->answer_rcode = 0;
t->stream->complete = on_stream_complete;
t->stream->transaction = t;
@@ -395,17 +544,11 @@ static int dns_transaction_open_tcp(DnsTransaction *t) {
if (t->scope->link)
t->stream->ifindex = t->scope->link->ifindex;
- return 0;
-}
+ dns_transaction_reset_answer(t);
-static void dns_transaction_next_dns_server(DnsTransaction *t) {
- assert(t);
+ t->tried_stream = true;
- t->server = dns_server_unref(t->server);
- t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source);
- t->dns_udp_fd = safe_close(t->dns_udp_fd);
-
- dns_scope_next_dns_server(t->scope);
+ return 0;
}
static void dns_transaction_cache_answer(DnsTransaction *t) {
@@ -428,6 +571,7 @@ static void dns_transaction_cache_answer(DnsTransaction *t) {
t->answer_rcode,
t->answer,
t->answer_authenticated,
+ t->answer_nsec_ttl,
0,
t->received->family,
&t->received->sender);
@@ -446,13 +590,86 @@ static bool dns_transaction_dnssec_is_live(DnsTransaction *t) {
return false;
}
+static int dns_transaction_dnssec_ready(DnsTransaction *t) {
+ DnsTransaction *dt;
+ Iterator i;
+
+ assert(t);
+
+ /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
+ * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
+
+ SET_FOREACH(dt, t->dnssec_transactions, i) {
+
+ switch (dt->state) {
+
+ case DNS_TRANSACTION_NULL:
+ case DNS_TRANSACTION_PENDING:
+ case DNS_TRANSACTION_VALIDATING:
+ /* Still ongoing */
+ return 0;
+
+ case DNS_TRANSACTION_RCODE_FAILURE:
+ if (dt->answer_rcode != DNS_RCODE_NXDOMAIN) {
+ log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode));
+ goto fail;
+ }
+
+ /* Fall-through: NXDOMAIN is good enough for us. This is because some DNS servers erronously
+ * return NXDOMAIN for empty non-terminals (Akamai...), and we need to handle that nicely, when
+ * asking for parent SOA or similar RRs to make unsigned proofs. */
+
+ case DNS_TRANSACTION_SUCCESS:
+ /* All good. */
+ break;
+
+ case DNS_TRANSACTION_DNSSEC_FAILED:
+ /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
+ * validationr result */
+
+ log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result));
+ t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */
+ dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
+ return 0;
+
+
+ default:
+ log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state));
+ goto fail;
+ }
+ }
+
+ /* All is ready, we can go and validate */
+ return 1;
+
+fail:
+ t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY;
+ dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
+ return 0;
+}
+
static void dns_transaction_process_dnssec(DnsTransaction *t) {
int r;
assert(t);
/* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
- if (dns_transaction_dnssec_is_live(t))
+ r = dns_transaction_dnssec_ready(t);
+ if (r < 0) {
+ dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
+ return;
+ }
+ if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
+ return;
+
+ /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
+ * restart the lookup immediately. */
+ r = dns_transaction_maybe_restart(t);
+ if (r < 0) {
+ dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
+ return;
+ }
+ if (r > 0) /* Transaction got restarted... */
return;
/* All our auxiliary DNSSEC transactions are complete now. Try
@@ -463,10 +680,19 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) {
return;
}
+ if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER &&
+ t->scope->dnssec_mode == DNSSEC_YES) {
+ /* We are not in automatic downgrade mode, and the
+ * server is bad, refuse operation. */
+ dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
+ return;
+ }
+
if (!IN_SET(t->answer_dnssec_result,
- _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */
- DNSSEC_VALIDATED, /* Answer is signed and validated successfully */
- DNSSEC_UNSIGNED)) { /* Answer is right-fully unsigned */
+ _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */
+ DNSSEC_VALIDATED, /* Answer is signed and validated successfully */
+ DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */
+ DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
return;
}
@@ -485,10 +711,12 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
assert(t);
assert(p);
- assert(t->state == DNS_TRANSACTION_PENDING);
assert(t->scope);
assert(t->scope->manager);
+ if (t->state != DNS_TRANSACTION_PENDING)
+ return;
+
/* Note that this call might invalidate the query. Callers
* should hence not attempt to access the query or transaction
* after calling this function. */
@@ -532,6 +760,11 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
break;
case DNS_PROTOCOL_DNS:
+ /* Note that we do not need to verify the
+ * addresses/port numbers of incoming traffic, as we
+ * invoked connect() on our UDP socket in which case
+ * the kernel already does the needed verification for
+ * us. */
break;
default:
@@ -571,17 +804,11 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
/* Request failed, immediately try again with reduced features */
log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p)));
- dns_server_packet_failed(t->server, t->current_features);
-
- r = dns_transaction_go(t);
- if (r < 0) {
- dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
- return;
- }
-
+ dns_server_packet_failed(t->server, t->current_feature_level);
+ dns_transaction_retry(t);
return;
- } else
- dns_server_packet_received(t->server, t->current_features, ts - t->start_usec, p->size);
+ } else if (DNS_PACKET_TC(p))
+ dns_server_packet_truncated(t->server, t->current_feature_level);
break;
@@ -602,6 +829,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
return;
}
+ log_debug("Reply truncated, retrying via TCP.");
+
/* Response was truncated, let's try again with good old TCP */
r = dns_transaction_open_tcp(t);
if (r == -ESRCH) {
@@ -609,34 +838,50 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS);
return;
}
+ if (r == -EOPNOTSUPP) {
+ /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
+ dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED);
+ return;
+ }
if (r < 0) {
/* On LLMNR, if we cannot connect to the host,
* we immediately give up */
- if (t->scope->protocol == DNS_PROTOCOL_LLMNR) {
+ if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
/* On DNS, couldn't send? Try immediately again, with a new server */
- dns_transaction_next_dns_server(t);
-
- r = dns_transaction_go(t);
- if (r < 0) {
- dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
- return;
- }
-
- return;
+ dns_transaction_retry(t);
}
+
+ return;
}
- /* Parse message, if it isn't parsed yet. */
+ /* After the superficial checks, actually parse the message. */
r = dns_packet_extract(p);
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
return;
}
+ /* Report that the OPT RR was missing */
+ if (t->server) {
+ if (!p->opt)
+ dns_server_packet_bad_opt(t->server, t->current_feature_level);
+
+ dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, ts - t->start_usec, p->size);
+ }
+
+ /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
+ r = dns_transaction_maybe_restart(t);
+ if (r < 0) {
+ dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
+ return;
+ }
+ if (r > 0) /* Transaction got restarted... */
+ return;
+
if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) {
/* Only consider responses with equivalent query section to the request */
@@ -654,9 +899,25 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
dns_answer_unref(t->answer);
t->answer = dns_answer_ref(p->answer);
t->answer_rcode = DNS_PACKET_RCODE(p);
+ t->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
t->answer_authenticated = false;
+ /* Block GC while starting requests for additional DNSSEC RRs */
+ t->block_gc++;
r = dns_transaction_request_dnssec_keys(t);
+ t->block_gc--;
+
+ /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
+ if (!dns_transaction_gc(t))
+ return;
+
+ /* Requesting additional keys might have resulted in
+ * this transaction to fail, since the auxiliary
+ * request failed for some reason. If so, we are not
+ * in pending state anymore, and we should exit
+ * quickly. */
+ if (t->state != DNS_TRANSACTION_PENDING)
+ return;
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
@@ -664,7 +925,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
if (r > 0) {
/* There are DNSSEC transactions pending now. Update the state accordingly. */
t->state = DNS_TRANSACTION_VALIDATING;
- dns_transaction_stop(t);
+ dns_transaction_close_connection(t);
+ dns_transaction_stop_timeout(t);
return;
}
}
@@ -681,53 +943,96 @@ static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *use
assert(t->scope);
r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p);
- if (r <= 0)
- return r;
+ if (ERRNO_IS_DISCONNECT(-r)) {
+ usec_t usec;
- if (dns_packet_validate_reply(p) > 0 &&
- DNS_PACKET_ID(p) == t->id)
- dns_transaction_process_reply(t, p);
- else
- log_debug("Invalid DNS packet, ignoring.");
+ /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next
+ * recvmsg(). Treat this like a lost packet. */
+
+ log_debug_errno(r, "Connection failure for DNS UDP packet: %m");
+ assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0);
+ dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level, usec - t->start_usec);
+
+ dns_transaction_retry(t);
+ return 0;
+ }
+ if (r < 0) {
+ dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
+ return 0;
+ }
+
+ r = dns_packet_validate_reply(p);
+ if (r < 0) {
+ log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m");
+ return 0;
+ }
+ if (r == 0) {
+ log_debug("Received inappropriate DNS packet as response, ignoring.");
+ return 0;
+ }
+ if (DNS_PACKET_ID(p) != t->id) {
+ log_debug("Received packet with incorrect transaction ID, ignoring.");
+ return 0;
+ }
+
+ dns_transaction_process_reply(t, p);
return 0;
}
-static int dns_transaction_emit(DnsTransaction *t) {
+static int dns_transaction_emit_udp(DnsTransaction *t) {
int r;
assert(t);
- if (t->scope->protocol == DNS_PROTOCOL_DNS && !t->server) {
- DnsServer *server = NULL;
- _cleanup_close_ int fd = -1;
-
- fd = dns_scope_udp_dns_socket(t->scope, &server);
- if (fd < 0)
- return fd;
+ if (t->scope->protocol == DNS_PROTOCOL_DNS) {
- r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t);
+ r = dns_transaction_pick_server(t);
if (r < 0)
return r;
- t->dns_udp_fd = fd;
- fd = -1;
- t->server = dns_server_ref(server);
- }
+ if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP)
+ return -EAGAIN;
+
+ if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type))
+ return -EOPNOTSUPP;
+
+ if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */
+ int fd;
+
+ dns_transaction_close_connection(t);
+
+ fd = dns_scope_socket_udp(t->scope, t->server, 53);
+ if (fd < 0)
+ return fd;
- r = dns_scope_emit(t->scope, t->dns_udp_fd, t->server, t->sent);
+ r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t);
+ if (r < 0) {
+ safe_close(fd);
+ return r;
+ }
+
+ (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp");
+ t->dns_udp_fd = fd;
+ }
+
+ r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level);
+ if (r < 0)
+ return r;
+ } else
+ dns_transaction_close_connection(t);
+
+ r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent);
if (r < 0)
return r;
- if (t->server)
- t->current_features = t->server->possible_features;
+ dns_transaction_reset_answer(t);
return 0;
}
static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) {
DnsTransaction *t = userdata;
- int r;
assert(s);
assert(t);
@@ -735,17 +1040,17 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat
if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) {
/* Timeout reached? Increase the timeout for the server used */
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_DNS:
assert(t->server);
-
- dns_server_packet_lost(t->server, t->current_features, usec - t->start_usec);
-
+ dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level, usec - t->start_usec);
break;
+
case DNS_PROTOCOL_LLMNR:
case DNS_PROTOCOL_MDNS:
dns_scope_packet_lost(t->scope, usec - t->start_usec);
-
break;
+
default:
assert_not_reached("Invalid DNS protocol.");
}
@@ -756,13 +1061,7 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat
log_debug("Timeout reached on transaction %" PRIu16 ".", t->id);
- /* ...and try again with a new server */
- dns_transaction_next_dns_server(t);
-
- r = dns_transaction_go(t);
- if (r < 0)
- dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
-
+ dns_transaction_retry(t);
return 0;
}
@@ -771,36 +1070,36 @@ static usec_t transaction_get_resend_timeout(DnsTransaction *t) {
assert(t->scope);
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_DNS:
assert(t->server);
-
return t->server->resend_timeout;
+
case DNS_PROTOCOL_MDNS:
assert(t->n_attempts > 0);
return (1 << (t->n_attempts - 1)) * USEC_PER_SEC;
+
case DNS_PROTOCOL_LLMNR:
return t->scope->resend_timeout;
+
default:
assert_not_reached("Invalid DNS protocol.");
}
}
static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) {
- bool had_stream;
int r;
assert(t);
- had_stream = !!t->stream;
-
- dns_transaction_stop(t);
+ dns_transaction_stop_timeout(t);
if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) {
dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED);
return 0;
}
- if (t->scope->protocol == DNS_PROTOCOL_LLMNR && had_stream) {
+ if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) {
/* If we already tried via a stream, then we don't
* retry on LLMNR. See RFC 4795, Section 2.7. */
dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED);
@@ -809,14 +1108,13 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) {
t->n_attempts++;
t->start_usec = ts;
- t->received = dns_packet_unref(t->received);
- t->answer = dns_answer_unref(t->answer);
- t->answer_rcode = 0;
- t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
+
+ dns_transaction_reset_answer(t);
+ dns_transaction_flush_dnssec_transactions(t);
/* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
if (t->scope->protocol == DNS_PROTOCOL_DNS) {
- r = dns_trust_anchor_lookup(&t->scope->manager->trust_anchor, t->key, &t->answer);
+ r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer);
if (r < 0)
return r;
if (r > 0) {
@@ -826,6 +1124,41 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) {
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
return 0;
}
+
+ if (dns_name_is_root(DNS_RESOURCE_KEY_NAME(t->key)) &&
+ t->key->type == DNS_TYPE_DS) {
+
+ /* Hmm, this is a request for the root DS? A
+ * DS RR doesn't exist in the root zone, and
+ * if our trust anchor didn't know it either,
+ * this means we cannot do any DNSSEC logic
+ * anymore. */
+
+ if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) {
+ /* We are in downgrade mode. In this
+ * case, synthesize an unsigned empty
+ * response, so that the any lookup
+ * depending on this one can continue
+ * assuming there was no DS, and hence
+ * the root zone was unsigned. */
+
+ t->answer_rcode = DNS_RCODE_SUCCESS;
+ t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR;
+ t->answer_authenticated = false;
+ dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
+ } else
+ /* If we are not in downgrade mode,
+ * then fail the lookup, because we
+ * cannot reasonably answer it. There
+ * might be DS RRs, but we don't know
+ * them, and the DNS server won't tell
+ * them to us (and even if it would,
+ * we couldn't validate it and trust
+ * it). */
+ dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR);
+
+ return 0;
+ }
}
/* Check the zone, but only if this transaction is not used
@@ -950,6 +1283,8 @@ static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
if (r < 0)
return r;
+ (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
+
other->state = DNS_TRANSACTION_PENDING;
other->next_attempt_after = ts;
@@ -986,7 +1321,7 @@ static int dns_transaction_make_packet(DnsTransaction *t) {
if (t->sent)
return 0;
- r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode == DNSSEC_YES);
+ r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO);
if (r < 0)
return r;
@@ -1041,10 +1376,12 @@ int dns_transaction_go(DnsTransaction *t) {
random_bytes(&jitter, sizeof(jitter));
switch (t->scope->protocol) {
+
case DNS_PROTOCOL_LLMNR:
jitter %= LLMNR_JITTER_INTERVAL_USEC;
accuracy = LLMNR_JITTER_INTERVAL_USEC;
break;
+
case DNS_PROTOCOL_MDNS:
jitter %= MDNS_JITTER_RANGE_USEC;
jitter += MDNS_JITTER_MIN_USEC;
@@ -1063,6 +1400,8 @@ int dns_transaction_go(DnsTransaction *t) {
if (r < 0)
return r;
+ (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
+
t->n_attempts = 0;
t->next_attempt_after = ts;
t->state = DNS_TRANSACTION_PENDING;
@@ -1093,7 +1432,11 @@ int dns_transaction_go(DnsTransaction *t) {
} else {
/* Try via UDP, and if that fails due to large size or lack of
* support try via TCP */
- r = dns_transaction_emit(t);
+ r = dns_transaction_emit_udp(t);
+ if (r == -EMSGSIZE)
+ log_debug("Sending query via TCP since it is too large.");
+ if (r == -EAGAIN)
+ log_debug("Sending query via TCP since server doesn't support UDP.");
if (r == -EMSGSIZE || r == -EAGAIN)
r = dns_transaction_open_tcp(t);
}
@@ -1102,14 +1445,20 @@ int dns_transaction_go(DnsTransaction *t) {
/* No servers to send this to? */
dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS);
return 0;
- } else if (r < 0) {
+ }
+ if (r == -EOPNOTSUPP) {
+ /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
+ dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED);
+ return 0;
+ }
+ if (r < 0) {
if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return 0;
}
/* Couldn't send? Try immediately again, with a new server */
- dns_transaction_next_dns_server(t);
+ dns_scope_next_dns_server(t->scope);
return dns_transaction_go(t);
}
@@ -1125,12 +1474,36 @@ int dns_transaction_go(DnsTransaction *t) {
if (r < 0)
return r;
+ (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout");
+
t->state = DNS_TRANSACTION_PENDING;
t->next_attempt_after = ts;
return 1;
}
+static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) {
+ DnsTransaction *n;
+ Iterator i;
+ int r;
+
+ assert(t);
+ assert(aux);
+
+ /* Try to find cyclic dependencies between transaction objects */
+
+ if (t == aux)
+ return 1;
+
+ SET_FOREACH(n, aux->dnssec_transactions, i) {
+ r = dns_transaction_find_cyclic(t, n);
+ if (r != 0)
+ return r;
+ }
+
+ return 0;
+}
+
static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) {
DnsTransaction *aux;
int r;
@@ -1149,6 +1522,18 @@ static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResource
*ret = aux;
return 0;
}
+
+ r = dns_transaction_find_cyclic(t, aux);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ log_debug("Detected potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).",
+ aux->id,
+ strna(dns_transaction_key_string(aux)),
+ t->id,
+ strna(dns_transaction_key_string(t)));
+ return -ELOOP;
+ }
}
r = set_ensure_allocated(&t->dnssec_transactions, NULL);
@@ -1185,14 +1570,8 @@ static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *
assert(t);
assert(key);
- r = dns_resource_key_equal(t->key, key);
- if (r < 0)
- return r;
- if (r > 0) /* Don't go in circles */
- return 0;
-
/* Try to get the data from the trust anchor */
- r = dns_trust_anchor_lookup(&t->scope->manager->trust_anchor, key, &a);
+ r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a);
if (r < 0)
return r;
if (r > 0) {
@@ -1205,6 +1584,8 @@ static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *
/* This didn't work, ask for it via the network/cache then. */
r = dns_transaction_add_dnssec_transaction(t, key, &aux);
+ if (r == -ELOOP) /* This would result in a cyclic dependency */
+ return 0;
if (r < 0)
return r;
@@ -1214,7 +1595,7 @@ static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *
return r;
}
- return 0;
+ return 1;
}
static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) {
@@ -1236,6 +1617,25 @@ static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags
return false;
}
+static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) {
+ int r;
+
+ assert(t);
+
+ /* Check whether the specified name is in the the NTA
+ * database, either in the global one, or the link-local
+ * one. */
+
+ r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name);
+ if (r != 0)
+ return r;
+
+ if (!t->scope->link)
+ return 0;
+
+ return set_contains(t->scope->link->dnssec_negative_trust_anchors, name);
+}
+
static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) {
int r;
@@ -1250,6 +1650,14 @@ static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) {
if (r > 0)
return false;
+ /* Is this key explicitly listed as a negative trust anchor?
+ * If so, it's nothing we need to care about */
+ r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(t->key));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return false;
+
/* The answer does not contain any RRs that match to the
* question. If so, let's see if there are any NSEC/NSEC3 RRs
* included. If not, the answer is unsigned. */
@@ -1300,6 +1708,44 @@ static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRec
return rr->key->type == DNS_TYPE_NSEC;
}
+static bool dns_transaction_dnssec_supported(DnsTransaction *t) {
+ assert(t);
+
+ /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
+ * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
+
+ if (t->scope->protocol != DNS_PROTOCOL_DNS)
+ return false;
+
+ /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
+ * be supported, hence return true. */
+ if (!t->server)
+ return true;
+
+ if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_DO)
+ return false;
+
+ return dns_server_dnssec_supported(t->server);
+}
+
+static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) {
+ DnsTransaction *dt;
+ Iterator i;
+
+ assert(t);
+
+ /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
+
+ if (!dns_transaction_dnssec_supported(t))
+ return false;
+
+ SET_FOREACH(dt, t->dnssec_transactions, i)
+ if (!dns_transaction_dnssec_supported(dt))
+ return false;
+
+ return true;
+}
+
int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
DnsResourceRecord *rr;
@@ -1315,20 +1761,31 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
* - For RRSIG we get the matching DNSKEY
* - For DNSKEY we get the matching DS
* - For unsigned SOA/NS we get the matching DS
- * - For unsigned CNAME/DNAME we get the parent SOA RR
+ * - For unsigned CNAME/DNAME/DS we get the parent SOA RR
* - For other unsigned RRs we get the matching SOA RR
* - For SOA/NS/DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR
* - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR
*/
- if (t->scope->dnssec_mode != DNSSEC_YES)
+ if (t->scope->dnssec_mode == DNSSEC_NO)
return 0;
+ if (t->answer_source != DNS_TRANSACTION_NETWORK)
+ return 0; /* We only need to validate stuff from the network */
+ if (!dns_transaction_dnssec_supported(t))
+ return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */
DNS_ANSWER_FOREACH(rr, t->answer) {
if (dns_type_is_pseudo(rr->key->type))
continue;
+ /* If this RR is in the negative trust anchor, we don't need to validate it. */
+ r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ continue;
+
switch (rr->key->type) {
case DNS_TYPE_RRSIG: {
@@ -1396,7 +1853,7 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
if (!ds)
return -ENOMEM;
- log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", t->id, DNS_RESOURCE_KEY_NAME(rr->key), dnssec_keytag(rr));
+ log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", t->id, DNS_RESOURCE_KEY_NAME(rr->key), dnssec_keytag(rr, false));
r = dns_transaction_request_dnssec_rr(t, ds);
if (r < 0)
return r;
@@ -1404,15 +1861,6 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
break;
}
- case DNS_TYPE_DS:
- case DNS_TYPE_NSEC:
- case DNS_TYPE_NSEC3:
- /* Don't acquire anything for
- * DS/NSEC/NSEC3. We require they come with an
- * RRSIG without us asking for anything, and
- * that's sufficient. */
- break;
-
case DNS_TYPE_SOA:
case DNS_TYPE_NS: {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL;
@@ -1448,6 +1896,7 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
break;
}
+ case DNS_TYPE_DS:
case DNS_TYPE_CNAME:
case DNS_TYPE_DNAME: {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL;
@@ -1458,7 +1907,10 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
* unsigned CNAME/DNAME RRs, maybe that's the
* apex. But do all that only if this is
* actually a response to our original
- * question. */
+ * question.
+ *
+ * Similar for DS RRs, which are signed when
+ * the parent SOA is signed. */
r = dns_transaction_is_primary_response(t, rr);
if (r < 0)
@@ -1472,6 +1924,12 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
if (r > 0)
continue;
+ r = dns_answer_has_dname_for_cname(t->answer, rr);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ continue;
+
name = DNS_RESOURCE_KEY_NAME(rr->key);
r = dns_name_parent(&name);
if (r < 0)
@@ -1483,7 +1941,7 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
if (!soa)
return -ENOMEM;
- log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key));
+ log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key));
r = dns_transaction_request_dnssec_rr(t, soa);
if (r < 0)
return r;
@@ -1494,10 +1952,11 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
default: {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL;
- /* For other unsigned RRsets, look for proof
- * the zone is unsigned, by requesting the SOA
- * RR of the zone. However, do so only if they
- * are directly relevant to our original
+ /* For other unsigned RRsets (including
+ * NSEC/NSEC3!), look for proof the zone is
+ * unsigned, by requesting the SOA RR of the
+ * zone. However, do so only if they are
+ * directly relevant to our original
* question. */
r = dns_transaction_is_primary_response(t, rr);
@@ -1516,7 +1975,7 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
if (!soa)
return -ENOMEM;
- log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key));
+ log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", t->id, DNS_RESOURCE_KEY_NAME(rr->key), dns_resource_record_to_string(rr));
r = dns_transaction_request_dnssec_rr(t, soa);
if (r < 0)
return r;
@@ -1570,69 +2029,15 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) {
}
void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) {
- int r;
-
assert(t);
assert(source);
- if (!IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING))
- return;
-
- /* Invoked whenever any of our auxiliary DNSSEC transactions
- completed its work. We copy any RRs from that transaction
- over into our list of validated keys -- but only if the
- answer is authenticated.
-
- Note that we fail our transaction if the auxiliary
- transaction failed, except on NXDOMAIN. This is because
- some broken DNS servers (Akamai...) will return NXDOMAIN
- for empty non-terminals. */
-
- switch (source->state) {
+ /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
+ we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
+ the state is VALIDATING however, we should check if we are complete now. */
- case DNS_TRANSACTION_DNSSEC_FAILED:
-
- log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(source->answer_dnssec_result));
- t->answer_dnssec_result = source->answer_dnssec_result; /* Copy error code over */
- dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
- break;
-
- case DNS_TRANSACTION_RCODE_FAILURE:
-
- if (source->answer_rcode != DNS_RCODE_NXDOMAIN) {
- log_debug("Auxiliary DNSSEC RR query failed with rcode=%i.", source->answer_rcode);
- goto fail;
- }
-
- /* fall-through: NXDOMAIN is good enough for us */
-
- case DNS_TRANSACTION_SUCCESS:
- if (source->answer_authenticated) {
- r = dns_answer_extend(&t->validated_keys, source->answer);
- if (r < 0) {
- log_error_errno(r, "Failed to merge validated DNSSEC key data: %m");
- goto fail;
- }
- }
-
- /* If the state is still PENDING, we are still in the loop
- * that adds further DNSSEC transactions, hence don't check if
- * we are ready yet. If the state is VALIDATING however, we
- * should check if we are complete now. */
- if (t->state == DNS_TRANSACTION_VALIDATING)
- dns_transaction_process_dnssec(t);
- break;
-
- default:
- log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(source->state));
- goto fail;
- }
-
- return;
-
-fail:
- t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY;
- dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED);
+ if (t->state == DNS_TRANSACTION_VALIDATING)
+ dns_transaction_process_dnssec(t);
}
static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) {
@@ -1647,7 +2052,7 @@ static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) {
DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) {
- r = dnssec_verify_dnskey_search(rr, t->validated_keys);
+ r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys);
if (r < 0)
return r;
if (r == 0)
@@ -1671,20 +2076,19 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
/* Checks if the RR we are looking for must be signed with an
* RRSIG. This is used for positive responses. */
- if (t->scope->dnssec_mode != DNSSEC_YES)
+ if (t->scope->dnssec_mode == DNSSEC_NO)
return false;
if (dns_type_is_pseudo(rr->key->type))
return -EINVAL;
- switch (rr->key->type) {
+ r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return false;
- case DNS_TYPE_DNSKEY:
- case DNS_TYPE_DS:
- case DNS_TYPE_NSEC:
- case DNS_TYPE_NSEC3:
- /* We never consider DNSKEY, DS, NSEC, NSEC3 RRs if they aren't signed. */
- return true;
+ switch (rr->key->type) {
case DNS_TYPE_RRSIG:
/* RRSIGs are the signatures themselves, they need no signing. */
@@ -1695,7 +2099,7 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
DnsTransaction *dt;
Iterator i;
- /* For SOA or NS RRs we look for a matching DS transaction, or a SOA transaction of the parent */
+ /* For SOA or NS RRs we look for a matching DS transaction */
SET_FOREACH(dt, t->dnssec_transactions, i) {
@@ -1726,13 +2130,18 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
return true;
}
+ case DNS_TYPE_DS:
case DNS_TYPE_CNAME:
case DNS_TYPE_DNAME: {
const char *parent = NULL;
DnsTransaction *dt;
Iterator i;
- /* CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. */
+ /*
+ * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA.
+ *
+ * DS RRs are signed if the parent is signed, hence also look at the parent SOA
+ */
SET_FOREACH(dt, t->dnssec_transactions, i) {
@@ -1747,6 +2156,9 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
if (r < 0)
return r;
if (r == 0) {
+ if (rr->key->type == DNS_TYPE_DS)
+ return true;
+
/* A CNAME/DNAME without a parent? That's sooo weird. */
log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id);
return -EBADMSG;
@@ -1769,7 +2181,7 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
DnsTransaction *dt;
Iterator i;
- /* Any other kind of RR. Let's see if our SOA lookup was authenticated */
+ /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */
SET_FOREACH(dt, t->dnssec_transactions, i) {
@@ -1796,6 +2208,66 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *
}}
}
+static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) {
+ DnsTransaction *dt;
+ const char *tld;
+ Iterator i;
+ int r;
+
+ /* If DNSSEC downgrade mode is on, checks whether the
+ * specified RR is one level below a TLD we have proven not to
+ * exist. In such a case we assume that this is a private
+ * domain, and permit it.
+ *
+ * This detects cases like the Fritz!Box router networks. Each
+ * Fritz!Box router serves a private "fritz.box" zone, in the
+ * non-existing TLD "box". Requests for the "fritz.box" domain
+ * are served by the router itself, while requests for the
+ * "box" domain will result in NXDOMAIN.
+ *
+ * Note that this logic is unable to detect cases where a
+ * router serves a private DNS zone directly under
+ * non-existing TLD. In such a case we cannot detect whether
+ * the TLD is supposed to exist or not, as all requests we
+ * make for it will be answered by the router's zone, and not
+ * by the root zone. */
+
+ assert(t);
+
+ if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE)
+ return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
+
+ tld = DNS_RESOURCE_KEY_NAME(key);
+ r = dns_name_parent(&tld);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return false; /* Already the root domain */
+
+ if (!dns_name_is_single_label(tld))
+ return false;
+
+ SET_FOREACH(dt, t->dnssec_transactions, i) {
+
+ if (dt->key->class != key->class)
+ continue;
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), tld);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ /* We found an auxiliary lookup we did for the TLD. If
+ * that returned with NXDOMAIN, we know the TLD didn't
+ * exist, and hence this might be a private zone. */
+
+ return dt->answer_rcode == DNS_RCODE_NXDOMAIN;
+ }
+
+ return false;
+}
+
static int dns_transaction_requires_nsec(DnsTransaction *t) {
DnsTransaction *dt;
const char *name;
@@ -1807,12 +2279,30 @@ static int dns_transaction_requires_nsec(DnsTransaction *t) {
/* Checks if we need to insist on NSEC/NSEC3 RRs for proving
* this negative reply */
- if (t->scope->dnssec_mode != DNSSEC_YES)
+ if (t->scope->dnssec_mode == DNSSEC_NO)
return false;
if (dns_type_is_pseudo(t->key->type))
return -EINVAL;
+ r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(t->key));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return false;
+
+ r = dns_transaction_in_private_tld(t, t->key);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ /* The lookup is from a TLD that is proven not to
+ * exist, and we are in downgrade mode, hence ignore
+ * that fact that we didn't get any NSEC RRs.*/
+
+ log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", dns_transaction_key_string(t));
+ return false;
+ }
+
name = DNS_RESOURCE_KEY_NAME(t->key);
if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS, DNS_TYPE_DS)) {
@@ -1855,9 +2345,173 @@ static int dns_transaction_requires_nsec(DnsTransaction *t) {
return true;
}
+static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) {
+ DnsResourceRecord *rrsig;
+ bool found = false;
+ int r;
+
+ /* Checks whether any of the DNSKEYs used for the RRSIGs for
+ * the specified RRset is authenticated (i.e. has a matching
+ * DS RR). */
+
+ r = dns_transaction_negative_trust_anchor_lookup(t, DNS_RESOURCE_KEY_NAME(rr->key));
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return false;
+
+ DNS_ANSWER_FOREACH(rrsig, t->answer) {
+ DnsTransaction *dt;
+ Iterator i;
+
+ r = dnssec_key_match_rrsig(rr->key, rrsig);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ SET_FOREACH(dt, t->dnssec_transactions, i) {
+
+ if (dt->key->class != rr->key->class)
+ continue;
+
+ if (dt->key->type == DNS_TYPE_DNSKEY) {
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), rrsig->rrsig.signer);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ /* OK, we found an auxiliary DNSKEY
+ * lookup. If that lookup is
+ * authenticated, report this. */
+
+ if (dt->answer_authenticated)
+ return true;
+
+ found = true;
+
+ } else if (dt->key->type == DNS_TYPE_DS) {
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), rrsig->rrsig.signer);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ /* OK, we found an auxiliary DS
+ * lookup. If that lookup is
+ * authenticated and non-zero, we
+ * won! */
+
+ if (!dt->answer_authenticated)
+ return false;
+
+ return dns_answer_match_key(dt->answer, dt->key, NULL);
+ }
+ }
+ }
+
+ return found ? false : -ENXIO;
+}
+
+static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) {
+ assert(t);
+ assert(rr);
+
+ /* We know that the root domain is signed, hence if it appears
+ * not to be signed, there's a problem with the DNS server */
+
+ return rr->key->class == DNS_CLASS_IN &&
+ dns_name_is_root(DNS_RESOURCE_KEY_NAME(rr->key));
+}
+
+static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) {
+ DnsResourceRecord *rr;
+ int r;
+
+ assert(t);
+
+ /* Maybe warn the user that we encountered a revoked DNSKEY
+ * for a key from our trust anchor. Note that we don't care
+ * whether the DNSKEY can be authenticated or not. It's
+ * sufficient if it is self-signed. */
+
+ DNS_ANSWER_FOREACH(rr, t->answer) {
+ r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) {
+ bool changed;
+ int r;
+
+ assert(t);
+
+ /* Removes all DNSKEY/DS objects from t->validated_keys that
+ * our trust anchors database considers revoked. */
+
+ do {
+ DnsResourceRecord *rr;
+
+ changed = false;
+
+ DNS_ANSWER_FOREACH(rr, t->validated_keys) {
+ r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ r = dns_answer_remove_by_rr(&t->validated_keys, rr);
+ if (r < 0)
+ return r;
+
+ assert(r > 0);
+ changed = true;
+ break;
+ }
+ }
+ } while (changed);
+
+ return 0;
+}
+
+static int dns_transaction_copy_validated(DnsTransaction *t) {
+ DnsTransaction *dt;
+ Iterator i;
+ int r;
+
+ assert(t);
+
+ /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
+
+ SET_FOREACH(dt, t->dnssec_transactions, i) {
+
+ if (DNS_TRANSACTION_IS_LIVE(dt->state))
+ continue;
+
+ if (!dt->answer_authenticated)
+ continue;
+
+ r = dns_answer_extend(&t->validated_keys, dt->answer);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
int dns_transaction_validate_dnssec(DnsTransaction *t) {
_cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL;
- bool dnskeys_finalized = false;
+ enum {
+ PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */
+ PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */
+ PHASE_ALL, /* Phase #3, validate everything else */
+ } phase;
DnsResourceRecord *rr;
DnsAnswerFlags flags;
int r;
@@ -1868,7 +2522,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
* t->validated_keys, let's see which RRs we can now
* authenticate with that. */
- if (t->scope->dnssec_mode != DNSSEC_YES)
+ if (t->scope->dnssec_mode == DNSSEC_NO)
return 0;
/* Already validated */
@@ -1886,33 +2540,83 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
if (t->answer_source != DNS_TRANSACTION_NETWORK)
return 0;
+ if (!dns_transaction_dnssec_supported_full(t)) {
+ /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
+ t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER;
+ log_debug("Not validating response, server lacks DNSSEC support.");
+ return 0;
+ }
+
log_debug("Validating response from transaction %" PRIu16 " (%s).", t->id, dns_transaction_key_string(t));
- /* First see if there are DNSKEYs we already known a validated DS for. */
+ /* First, see if this response contains any revoked trust
+ * anchors we care about */
+ r = dns_transaction_check_revoked_trust_anchors(t);
+ if (r < 0)
+ return r;
+
+ /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
+ r = dns_transaction_copy_validated(t);
+ if (r < 0)
+ return r;
+
+ /* Second, see if there are DNSKEYs we already know a
+ * validated DS for. */
r = dns_transaction_validate_dnskey_by_ds(t);
if (r < 0)
return r;
+ /* Fourth, remove all DNSKEY and DS RRs again that our trust
+ * anchor says are revoked. After all we might have marked
+ * some keys revoked above, but they might still be lingering
+ * in our validated_keys list. */
+ r = dns_transaction_invalidate_revoked_keys(t);
+ if (r < 0)
+ return r;
+
+ phase = PHASE_DNSKEY;
for (;;) {
- bool changed = false;
+ bool changed = false, have_nsec = false;
DNS_ANSWER_FOREACH(rr, t->answer) {
+ DnsResourceRecord *rrsig = NULL;
DnssecResult result;
- if (rr->key->type == DNS_TYPE_RRSIG)
+ switch (rr->key->type) {
+
+ case DNS_TYPE_RRSIG:
continue;
- r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result);
- if (r < 0)
- return r;
+ case DNS_TYPE_DNSKEY:
+ /* We validate DNSKEYs only in the DNSKEY and ALL phases */
+ if (phase == PHASE_NSEC)
+ continue;
+ break;
+
+ case DNS_TYPE_NSEC:
+ case DNS_TYPE_NSEC3:
+ have_nsec = true;
+
+ /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
+ if (phase == PHASE_DNSKEY)
+ continue;
+
+ break;
- if (log_get_max_level() >= LOG_DEBUG) {
- _cleanup_free_ char *rrs = NULL;
+ default:
+ /* We validate all other RRs only in the ALL phases */
+ if (phase != PHASE_ALL)
+ continue;
- (void) dns_resource_record_to_string(rr, &rrs);
- log_debug("Looking at %s: %s", rrs ? strstrip(rrs) : "???", dnssec_result_to_string(result));
+ break;
}
+ r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig);
+ if (r < 0)
+ return r;
+
+ log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result));
+
if (result == DNSSEC_VALIDATED) {
if (rr->key->type == DNS_TYPE_DNSKEY) {
@@ -1925,6 +2629,14 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED);
if (r < 0)
return r;
+
+ /* some of the DNSKEYs we just
+ * added might already have
+ * been revoked, remove them
+ * again in that case. */
+ r = dns_transaction_invalidate_revoked_keys(t);
+ if (r < 0)
+ return r;
}
/* Add the validated RRset to the new
@@ -1936,68 +2648,203 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
if (r < 0)
return r;
+ t->scope->manager->n_dnssec_secure++;
+
/* Exit the loop, we dropped something from the answer, start from the beginning */
changed = true;
break;
+ }
+
+ /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
+ * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, we
+ * cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
+ if (phase != PHASE_ALL)
+ continue;
- } else if (dnskeys_finalized) {
- /* If we haven't read all DNSKEYs yet
- * a negative result of the validation
- * is irrelevant, as there might be
- * more DNSKEYs coming. */
+ if (result == DNSSEC_VALIDATED_WILDCARD) {
+ bool authenticated = false;
+ const char *source;
- if (result == DNSSEC_NO_SIGNATURE) {
- r = dns_transaction_requires_rrsig(t, rr);
+ /* This RRset validated, but as a wildcard. This means we need to prove via NSEC/NSEC3
+ * that no matching non-wildcard RR exists.*/
+
+ /* First step, determine the source of synthesis */
+ r = dns_resource_record_source(rrsig, &source);
+ if (r < 0)
+ return r;
+
+ r = dnssec_test_positive_wildcard(
+ validated,
+ DNS_RESOURCE_KEY_NAME(rr->key),
+ source,
+ rrsig->rrsig.signer,
+ &authenticated);
+
+ /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
+ if (r == 0)
+ result = DNSSEC_INVALID;
+ else {
+ r = dns_answer_move_by_key(&validated, &t->answer, rr->key, authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0);
+ if (r < 0)
+ return r;
+
+ if (authenticated)
+ t->scope->manager->n_dnssec_secure++;
+ else
+ t->scope->manager->n_dnssec_insecure++;
+
+ /* Exit the loop, we dropped something from the answer, start from the beginning */
+ changed = true;
+ break;
+ }
+ }
+
+ if (result == DNSSEC_NO_SIGNATURE) {
+ r = dns_transaction_requires_rrsig(t, rr);
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ /* Data does not require signing. In that case, just copy it over,
+ * but remember that this is by no means authenticated.*/
+ r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0);
if (r < 0)
return r;
- if (r == 0) {
- /* Data does not require signing. In that case, just copy it over,
- * but remember that this is by no means authenticated.*/
+
+ t->scope->manager->n_dnssec_insecure++;
+ changed = true;
+ break;
+ }
+
+ r = dns_transaction_known_signed(t, rr);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ /* This is an RR we know has to be signed. If it isn't this means
+ * the server is not attaching RRSIGs, hence complain. */
+
+ dns_server_packet_rrsig_missing(t->server, t->current_feature_level);
+
+ if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) {
+
+ /* Downgrading is OK? If so, just consider the information unsigned */
+
r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0);
if (r < 0)
return r;
+ t->scope->manager->n_dnssec_insecure++;
changed = true;
break;
}
+
+ /* Otherwise, fail */
+ t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER;
+ return 0;
}
- r = dns_transaction_is_primary_response(t, rr);
+ r = dns_transaction_in_private_tld(t, rr->key);
if (r < 0)
return r;
if (r > 0) {
- /* This is a primary response
- * to our question, and it
- * failed validation. That's
- * fatal. */
- t->answer_dnssec_result = result;
- return 0;
+ _cleanup_free_ char *s = NULL;
+
+ /* The data is from a TLD that is proven not to exist, and we are in downgrade
+ * mode, hence ignore the fact that this was not signed. */
+
+ (void) dns_resource_key_to_string(rr->key, &s);
+ log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", strna(s ? strstrip(s) : NULL));
+
+ r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0);
+ if (r < 0)
+ return r;
+
+ t->scope->manager->n_dnssec_insecure++;
+ changed = true;
+ break;
}
+ }
- /* This is just some auxiliary
- * data. Just remove the RRset and
- * continue. */
- r = dns_answer_remove_by_key(&t->answer, rr->key);
+ if (IN_SET(result,
+ DNSSEC_MISSING_KEY,
+ DNSSEC_SIGNATURE_EXPIRED,
+ DNSSEC_UNSUPPORTED_ALGORITHM)) {
+
+ r = dns_transaction_dnskey_authenticated(t, rr);
+ if (r < 0 && r != -ENXIO)
+ return r;
+ if (r == 0) {
+ /* The DNSKEY transaction was not authenticated, this means there's
+ * no DS for this, which means it's OK if no keys are found for this signature. */
+
+ r = dns_answer_move_by_key(&validated, &t->answer, rr->key, 0);
+ if (r < 0)
+ return r;
+
+ t->scope->manager->n_dnssec_insecure++;
+ changed = true;
+ break;
+ }
+ }
+
+ if (IN_SET(result,
+ DNSSEC_INVALID,
+ DNSSEC_SIGNATURE_EXPIRED,
+ DNSSEC_NO_SIGNATURE))
+ t->scope->manager->n_dnssec_bogus++;
+ else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */
+ t->scope->manager->n_dnssec_indeterminate++;
+
+ r = dns_transaction_is_primary_response(t, rr);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+
+ /* Look for a matching DNAME for this CNAME */
+ r = dns_answer_has_dname_for_cname(t->answer, rr);
if (r < 0)
return r;
+ if (r == 0) {
+ /* Also look among the stuff we already validated */
+ r = dns_answer_has_dname_for_cname(validated, rr);
+ if (r < 0)
+ return r;
+ }
- /* Exit the loop, we dropped something from the answer, start from the beginning */
- changed = true;
- break;
+ if (r == 0) {
+ /* This is a primary response to our question, and it failed validation. That's
+ * fatal. */
+ t->answer_dnssec_result = result;
+ return 0;
+ }
+
+ /* This is a primary response, but we do have a DNAME RR in the RR that can replay this
+ * CNAME, hence rely on that, and we can remove the CNAME in favour of it. */
}
+
+ /* This is just some auxiliary data. Just remove the RRset and continue. */
+ r = dns_answer_remove_by_key(&t->answer, rr->key);
+ if (r < 0)
+ return r;
+
+ /* Exit the loop, we dropped something from the answer, start from the beginning */
+ changed = true;
+ break;
}
+ /* Restart the inner loop as long as we managed to achieve something */
if (changed)
continue;
- if (!dnskeys_finalized) {
- /* OK, now we know we have added all DNSKEYs
- * we possibly could to our validated
- * list. Now run the whole thing once more,
- * and strip everything we still cannot
- * validate.
- */
- dnskeys_finalized = true;
+ if (phase == PHASE_DNSKEY && have_nsec) {
+ /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
+ phase = PHASE_NSEC;
+ continue;
+ }
+
+ if (phase != PHASE_ALL) {
+ /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. Note that in this
+ * third phase we start to remove RRs we couldn't validate. */
+ phase = PHASE_ALL;
continue;
}
@@ -2030,9 +2877,10 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
} else if (r == 0) {
DnssecNsecResult nr;
+ bool authenticated = false;
/* Bummer! Let's check NSEC/NSEC3 */
- r = dnssec_test_nsec(t->answer, t->key, &nr);
+ r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl);
if (r < 0)
return r;
@@ -2043,7 +2891,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t));
t->answer_dnssec_result = DNSSEC_VALIDATED;
t->answer_rcode = DNS_RCODE_NXDOMAIN;
- t->answer_authenticated = true;
+ t->answer_authenticated = authenticated;
break;
case DNSSEC_NSEC_NODATA:
@@ -2051,7 +2899,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t));
t->answer_dnssec_result = DNSSEC_VALIDATED;
t->answer_rcode = DNS_RCODE_SUCCESS;
- t->answer_authenticated = true;
+ t->answer_authenticated = authenticated;
break;
case DNSSEC_NSEC_OPTOUT:
@@ -2082,6 +2930,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
break;
case DNSSEC_NSEC_FOUND:
+ case DNSSEC_NSEC_CNAME:
/* NSEC says it needs to be there, but we couldn't find it? Bummer! */
t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH;
break;
@@ -2118,6 +2967,8 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX]
[DNS_TRANSACTION_RESOURCES] = "resources",
[DNS_TRANSACTION_ABORTED] = "aborted",
[DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed",
+ [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor",
+ [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported",
};
DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState);