diff options
Diffstat (limited to 'src/resolve/resolved-dns-transaction.c')
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 1512 |
1 files changed, 1398 insertions, 114 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 1103a34c6f..347b1683f9 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -24,6 +24,7 @@ #include "dns-domain.h" #include "fd-util.h" #include "random-util.h" +#include "resolved-dns-cache.h" #include "resolved-dns-transaction.h" #include "resolved-llmnr.h" #include "string-table.h" @@ -31,6 +32,7 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) { DnsQueryCandidate *c; DnsZoneItem *i; + DnsTransaction *z; if (!t) return NULL; @@ -58,15 +60,27 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) { dns_resource_key_unref(t->key); - while ((c = set_steal_first(t->query_candidates))) + while ((c = set_steal_first(t->notify_query_candidates))) set_remove(c->transactions, t); + set_free(t->notify_query_candidates); - set_free(t->query_candidates); - - while ((i = set_steal_first(t->zone_items))) + while ((i = set_steal_first(t->notify_zone_items))) i->probe_transaction = NULL; - set_free(t->zone_items); + set_free(t->notify_zone_items); + + while ((z = set_steal_first(t->notify_transactions))) + 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); + } + set_free(t->dnssec_transactions); + + dns_answer_unref(t->validated_keys); + free(t->key_string); free(t); return NULL; } @@ -79,7 +93,9 @@ void dns_transaction_gc(DnsTransaction *t) { if (t->block_gc > 0) return; - if (set_isempty(t->query_candidates) && set_isempty(t->zone_items)) + if (set_isempty(t->notify_query_candidates) && + set_isempty(t->notify_zone_items) && + set_isempty(t->notify_transactions)) dns_transaction_free(t); } @@ -91,6 +107,14 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) assert(s); assert(key); + /* Don't allow looking up invalid or pseudo RRs */ + if (!dns_type_is_valid_query(key->type)) + return -EINVAL; + + /* We only support the IN class */ + if (key->class != DNS_CLASS_IN && key->class != DNS_CLASS_ANY) + return -EOPNOTSUPP; + r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); if (r < 0) return r; @@ -105,6 +129,7 @@ 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->key = dns_resource_key_ref(key); /* Find a fresh, unused transaction id */ @@ -158,7 +183,9 @@ static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { in_addr_to_string(p->family, &p->sender, &pretty); - log_debug("Transaction on scope %s on %s/%s got tentative packet from %s", + log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", + t->id, + dns_transaction_key_string(t), dns_protocol_to_string(t->scope->protocol), t->scope->link ? t->scope->link->name : "*", t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), @@ -174,7 +201,7 @@ static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); t->block_gc++; - while ((z = set_first(t->zone_items))) { + while ((z = set_first(t->notify_zone_items))) { /* First, make sure the zone item drops the reference * to us */ dns_zone_item_probe_stop(z); @@ -191,21 +218,25 @@ static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { DnsQueryCandidate *c; DnsZoneItem *z; + DnsTransaction *d; Iterator i; assert(t); - assert(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING)); + assert(!DNS_TRANSACTION_IS_LIVE(state)); /* Note that this call might invalidate the query. Callers * should hence not attempt to access the query or transaction * after calling this function. */ - log_debug("Transaction on scope %s on %s/%s now complete with <%s> from %s", + log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", + t->id, + dns_transaction_key_string(t), dns_protocol_to_string(t->scope->protocol), t->scope->link ? t->scope->link->name : "*", t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family), dns_transaction_state_to_string(state), - t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source)); + t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), + t->answer_authenticated ? "authenticated" : "unsigned"); t->state = state; @@ -214,12 +245,42 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { /* Notify all queries that are interested, but make sure the * transaction isn't freed while we are still looking at it */ t->block_gc++; - SET_FOREACH(c, t->query_candidates, i) - dns_query_candidate_ready(c); - SET_FOREACH(z, t->zone_items, i) - dns_zone_item_ready(z); - t->block_gc--; + SET_FOREACH(c, t->notify_query_candidates, i) + dns_query_candidate_notify(c); + SET_FOREACH(z, t->notify_zone_items, i) + dns_zone_item_notify(z); + + if (!set_isempty(t->notify_transactions)) { + DnsTransaction **nt; + unsigned j, n = 0; + + /* We need to be careful when notifying other + * transactions, as that might destroy other + * transactions in our list. Hence, in order to be + * able to safely iterate through the list of + * transactions, take a GC lock on all of them + * first. Then, in a second loop, notify them, but + * first unlock that specific transaction. */ + + nt = newa(DnsTransaction*, set_size(t->notify_transactions)); + SET_FOREACH(d, t->notify_transactions, i) { + nt[n++] = d; + d->block_gc++; + } + + assert(n == set_size(t->notify_transactions)); + + for (j = 0; j < n; j++) { + if (set_contains(t->notify_transactions, nt[j])) + dns_transaction_notify(nt[j], t); + + nt[j]->block_gc--; + dns_transaction_gc(nt[j]); + } + } + + t->block_gc--; dns_transaction_gc(t); } @@ -243,7 +304,7 @@ static int on_stream_complete(DnsStream *s, int error) { } if (dns_packet_validate_reply(p) <= 0) { - log_debug("Invalid LLMNR TCP packet."); + log_debug("Invalid TCP reply packet."); dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); return 0; } @@ -347,6 +408,77 @@ static void dns_transaction_next_dns_server(DnsTransaction *t) { dns_scope_next_dns_server(t->scope); } +static void dns_transaction_cache_answer(DnsTransaction *t) { + assert(t); + + /* For mDNS we cache whenever we get the packet, rather than + * in each transaction. */ + if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) + return; + + /* We never cache if this packet is from the local host, under + * the assumption that a locally running DNS server would + * cache this anyway, and probably knows better when to flush + * the cache then we could. */ + if (!DNS_PACKET_SHALL_CACHE(t->received)) + return; + + dns_cache_put(&t->scope->cache, + t->key, + t->answer_rcode, + t->answer, + t->answer_authenticated, + 0, + t->received->family, + &t->received->sender); +} + +static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { + DnsTransaction *dt; + Iterator i; + + assert(t); + + SET_FOREACH(dt, t->dnssec_transactions, i) + if (DNS_TRANSACTION_IS_LIVE(dt->state)) + return true; + + return false; +} + +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)) + return; + + /* All our auxiliary DNSSEC transactions are complete now. Try + * to validate our RRset now. */ + r = dns_transaction_validate_dnssec(t); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); + 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 */ + dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); + return; + } + + dns_transaction_cache_answer(t); + + if (t->answer_rcode == DNS_RCODE_SUCCESS) + dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); + else + dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); +} + void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { usec_t ts; int r; @@ -361,7 +493,10 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { * should hence not attempt to access the query or transaction * after calling this function. */ + log_debug("Processing incoming packet on transaction %" PRIu16".", t->id); + switch (t->scope->protocol) { + case DNS_PROTOCOL_LLMNR: assert(t->scope->link); @@ -384,6 +519,18 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { break; + case DNS_PROTOCOL_MDNS: + assert(t->scope->link); + + /* For mDNS we will not accept any packets from other interfaces */ + if (p->ifindex != t->scope->link->ifindex) + return; + + if (p->family != t->scope->family) + return; + + break; + case DNS_PROTOCOL_DNS: break; @@ -415,12 +562,13 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); switch (t->scope->protocol) { + case DNS_PROTOCOL_DNS: assert(t->server); if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { - /* request failed, immediately try again with reduced features */ + /* 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); @@ -436,16 +584,24 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { dns_server_packet_received(t->server, t->current_features, ts - t->start_usec, p->size); break; + case DNS_PROTOCOL_LLMNR: case DNS_PROTOCOL_MDNS: dns_scope_packet_received(t->scope, ts - t->start_usec); - break; + default: - break; + assert_not_reached("Invalid DNS protocol."); } if (DNS_PACKET_TC(p)) { + + /* Truncated packets for mDNS are not allowed. Give up immediately. */ + if (t->scope->protocol == DNS_PROTOCOL_MDNS) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + /* Response was truncated, let's try again with good old TCP */ r = dns_transaction_open_tcp(t); if (r == -ESRCH) { @@ -474,41 +630,46 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { } } - /* Parse and update the cache */ + /* Parse message, if it isn't parsed yet. */ r = dns_packet_extract(p); if (r < 0) { dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); return; } - /* Only consider responses with equivalent query section to the request */ - if (p->question->n_keys != 1 || dns_resource_key_equal(p->question->keys[0], t->key) <= 0) { - dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); - return; + if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) { + + /* Only consider responses with equivalent query section to the request */ + r = dns_packet_is_reply_for(p, t->key); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); + return; + } + if (r == 0) { + dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); + return; + } + + /* Install the answer as answer to the transaction */ + dns_answer_unref(t->answer); + t->answer = dns_answer_ref(p->answer); + t->answer_rcode = DNS_PACKET_RCODE(p); + t->answer_authenticated = false; + + r = dns_transaction_request_dnssec_keys(t); + if (r < 0) { + dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); + return; + } + if (r > 0) { + /* There are DNSSEC transactions pending now. Update the state accordingly. */ + t->state = DNS_TRANSACTION_VALIDATING; + dns_transaction_stop(t); + return; + } } - /* Install the answer as answer to the transaction */ - dns_answer_unref(t->answer); - t->answer = dns_answer_ref(p->answer); - t->answer_rcode = DNS_PACKET_RCODE(p); - t->answer_authenticated = t->scope->dnssec_mode == DNSSEC_TRUST && DNS_PACKET_AD(p); - - /* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */ - if (DNS_PACKET_SHALL_CACHE(p)) - dns_cache_put(&t->scope->cache, - t->key, - DNS_PACKET_RCODE(p), - p->answer, - DNS_PACKET_ANCOUNT(p), - t->answer_authenticated, - 0, - p->family, - &p->sender); - - if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS) - dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); - else - dns_transaction_complete(t, DNS_TRANSACTION_FAILURE); + dns_transaction_process_dnssec(t); } static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { @@ -527,7 +688,7 @@ static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *use DNS_PACKET_ID(p) == t->id) dns_transaction_process_reply(t, p); else - log_debug("Invalid DNS packet."); + log_debug("Invalid DNS packet, ignoring."); return 0; } @@ -571,23 +732,30 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat assert(s); assert(t); - /* Timeout reached? Increase the timeout for the server used */ - switch (t->scope->protocol) { - case DNS_PROTOCOL_DNS: - assert(t->server); + 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->current_features, usec - t->start_usec); - break; - case DNS_PROTOCOL_LLMNR: - case DNS_PROTOCOL_MDNS: - dns_scope_packet_lost(t->scope, 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."); + break; + default: + assert_not_reached("Invalid DNS protocol."); + } + + if (t->initial_jitter_scheduled) + t->initial_jitter_elapsed = true; } + log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); + /* ...and try again with a new server */ dns_transaction_next_dns_server(t); @@ -598,38 +766,6 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat return 0; } -static int dns_transaction_make_packet(DnsTransaction *t) { - _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - int r; - - assert(t); - - if (t->sent) - return 0; - - r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode == DNSSEC_YES); - if (r < 0) - return r; - - r = dns_scope_good_key(t->scope, t->key); - if (r < 0) - return r; - if (r == 0) - return -EDOM; - - r = dns_packet_append_key(p, t->key, NULL); - if (r < 0) - return r; - - DNS_PACKET_HEADER(p)->qdcount = htobe16(1); - DNS_PACKET_HEADER(p)->id = t->id; - - t->sent = p; - p = NULL; - - return 0; -} - static usec_t transaction_get_resend_timeout(DnsTransaction *t) { assert(t); assert(t->scope); @@ -639,17 +775,18 @@ static usec_t transaction_get_resend_timeout(DnsTransaction *t) { assert(t->server); return t->server->resend_timeout; - case DNS_PROTOCOL_LLMNR: 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."); } } -int dns_transaction_go(DnsTransaction *t) { +static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { bool had_stream; - usec_t ts; int r; assert(t); @@ -658,11 +795,6 @@ int dns_transaction_go(DnsTransaction *t) { dns_transaction_stop(t); - log_debug("Excercising transaction on scope %s on %s/%s", - dns_protocol_to_string(t->scope->protocol), - t->scope->link ? t->scope->link->name : "*", - t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family)); - if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); return 0; @@ -675,8 +807,6 @@ int dns_transaction_go(DnsTransaction *t) { return 0; } - assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); - t->n_attempts++; t->start_usec = ts; t->received = dns_packet_unref(t->received); @@ -700,7 +830,7 @@ int dns_transaction_go(DnsTransaction *t) { /* Check the zone, but only if this transaction is not used * for probing or verifying a zone item. */ - if (set_isempty(t->zone_items)) { + if (set_isempty(t->notify_zone_items)) { r = dns_zone_lookup(&t->scope->zone, t->key, &t->answer, NULL, NULL); if (r < 0) @@ -716,7 +846,7 @@ int dns_transaction_go(DnsTransaction *t) { /* Check the cache, but only if this transaction is not used * for probing or verifying a zone item. */ - if (set_isempty(t->zone_items)) { + if (set_isempty(t->notify_zone_items)) { /* Before trying the cache, let's make sure we figured out a * server to use. Should this cause a change of server this @@ -734,36 +864,210 @@ int dns_transaction_go(DnsTransaction *t) { if (t->answer_rcode == DNS_RCODE_SUCCESS) dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); else - dns_transaction_complete(t, DNS_TRANSACTION_FAILURE); + dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); return 0; } } - if (t->scope->protocol == DNS_PROTOCOL_LLMNR && !t->initial_jitter) { - usec_t jitter; + return 1; +} + +static int dns_transaction_make_packet_mdns(DnsTransaction *t) { + + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + bool add_known_answers = false; + DnsTransaction *other; + unsigned qdcount; + usec_t ts; + int r; + + assert(t); + assert(t->scope->protocol == DNS_PROTOCOL_MDNS); + + /* Discard any previously prepared packet, so we can start over and coalesce again */ + t->sent = dns_packet_unref(t->sent); + + r = dns_packet_new_query(&p, t->scope->protocol, 0, false); + if (r < 0) + return r; + + r = dns_packet_append_key(p, t->key, NULL); + if (r < 0) + return r; + + qdcount = 1; + + if (dns_key_is_shared(t->key)) + add_known_answers = true; + + /* + * For mDNS, we want to coalesce as many open queries in pending transactions into one single + * query packet on the wire as possible. To achieve that, we iterate through all pending transactions + * in our current scope, and see whether their timing contraints allow them to be sent. + */ + + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { + + /* Skip ourselves */ + if (other == t) + continue; + + if (other->state != DNS_TRANSACTION_PENDING) + continue; + + if (other->next_attempt_after > ts) + continue; + + if (qdcount >= UINT16_MAX) + break; + + r = dns_packet_append_key(p, other->key, NULL); + + /* + * If we can't stuff more questions into the packet, just give up. + * One of the 'other' transactions will fire later and take care of the rest. + */ + if (r == -EMSGSIZE) + break; + + if (r < 0) + return r; + + r = dns_transaction_prepare(other, ts); + if (r <= 0) + continue; + + ts += transaction_get_resend_timeout(other); + + r = sd_event_add_time( + other->scope->manager->event, + &other->timeout_event_source, + clock_boottime_or_monotonic(), + ts, 0, + on_transaction_timeout, other); + if (r < 0) + return r; + + other->state = DNS_TRANSACTION_PENDING; + other->next_attempt_after = ts; + + qdcount ++; + + if (dns_key_is_shared(other->key)) + add_known_answers = true; + } + + DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); + + /* Append known answer section if we're asking for any shared record */ + if (add_known_answers) { + r = dns_cache_export_shared_to_packet(&t->scope->cache, p); + if (r < 0) + return r; + } + + t->sent = p; + p = NULL; + + return 0; +} + +static int dns_transaction_make_packet(DnsTransaction *t) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + int r; + + assert(t); + + if (t->scope->protocol == DNS_PROTOCOL_MDNS) + return dns_transaction_make_packet_mdns(t); + + if (t->sent) + return 0; + + r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode == DNSSEC_YES); + if (r < 0) + return r; + + r = dns_scope_good_key(t->scope, t->key); + if (r < 0) + return r; + if (r == 0) + return -EDOM; + + r = dns_packet_append_key(p, t->key, NULL); + if (r < 0) + return r; + + DNS_PACKET_HEADER(p)->qdcount = htobe16(1); + DNS_PACKET_HEADER(p)->id = t->id; + + t->sent = p; + p = NULL; + + return 0; +} + +int dns_transaction_go(DnsTransaction *t) { + usec_t ts; + int r; + + assert(t); + + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); + + r = dns_transaction_prepare(t, ts); + if (r <= 0) + return r; + + log_debug("Excercising transaction %" PRIu16 " for <%s> on scope %s on %s/%s.", + t->id, + dns_transaction_key_string(t), + dns_protocol_to_string(t->scope->protocol), + t->scope->link ? t->scope->link->name : "*", + t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family)); + + if (!t->initial_jitter_scheduled && + (t->scope->protocol == DNS_PROTOCOL_LLMNR || + t->scope->protocol == DNS_PROTOCOL_MDNS)) { + usec_t jitter, accuracy; /* RFC 4795 Section 2.7 suggests all queries should be * delayed by a random time from 0 to JITTER_INTERVAL. */ - t->initial_jitter = true; + t->initial_jitter_scheduled = true; random_bytes(&jitter, sizeof(jitter)); - jitter %= LLMNR_JITTER_INTERVAL_USEC; + + 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; + accuracy = MDNS_JITTER_RANGE_USEC; + break; + default: + assert_not_reached("bad protocol"); + } r = sd_event_add_time( t->scope->manager->event, &t->timeout_event_source, clock_boottime_or_monotonic(), - ts + jitter, - LLMNR_JITTER_INTERVAL_USEC, + ts + jitter, accuracy, on_transaction_timeout, t); if (r < 0) return r; t->n_attempts = 0; + t->next_attempt_after = ts; t->state = DNS_TRANSACTION_PENDING; - log_debug("Delaying LLMNR transaction for " USEC_FMT "us.", jitter); + log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); return 0; } @@ -810,23 +1114,1002 @@ int dns_transaction_go(DnsTransaction *t) { return dns_transaction_go(t); } + ts += transaction_get_resend_timeout(t); + r = sd_event_add_time( t->scope->manager->event, &t->timeout_event_source, clock_boottime_or_monotonic(), - ts + transaction_get_resend_timeout(t), 0, + ts, 0, on_transaction_timeout, t); if (r < 0) return r; t->state = DNS_TRANSACTION_PENDING; + t->next_attempt_after = ts; + + return 1; +} + +static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { + DnsTransaction *aux; + int r; + + assert(t); + assert(ret); + assert(key); + + aux = dns_scope_find_transaction(t->scope, key, true); + if (!aux) { + r = dns_transaction_new(&aux, t->scope, key); + if (r < 0) + return r; + } else { + if (set_contains(t->dnssec_transactions, aux)) { + *ret = aux; + return 0; + } + } + + r = set_ensure_allocated(&t->dnssec_transactions, NULL); + if (r < 0) + goto gc; + + r = set_ensure_allocated(&aux->notify_transactions, NULL); + if (r < 0) + goto gc; + + r = set_put(t->dnssec_transactions, aux); + if (r < 0) + goto gc; + + r = set_put(aux->notify_transactions, t); + if (r < 0) { + (void) set_remove(t->dnssec_transactions, aux); + goto gc; + } + + *ret = aux; return 1; + +gc: + dns_transaction_gc(aux); + return r; +} + +static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { + _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; + DnsTransaction *aux; + int r; + + 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); + if (r < 0) + return r; + if (r > 0) { + r = dns_answer_extend(&t->validated_keys, a); + if (r < 0) + return r; + + return 0; + } + + /* This didn't work, ask for it via the network/cache then. */ + r = dns_transaction_add_dnssec_transaction(t, key, &aux); + if (r < 0) + return r; + + if (aux->state == DNS_TRANSACTION_NULL) { + r = dns_transaction_go(aux); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { + int r; + + assert(t); + + /* Checks whether the answer is positive, i.e. either a direct + * answer to the question, or a CNAME/DNAME for it */ + + r = dns_answer_match_key(t->answer, t->key, flags); + if (r != 0) + return r; + + r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); + if (r != 0) + return r; + + return false; +} + +static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { + int r; + + assert(t); + + /* Checks whether the answer is negative, and lacks NSEC/NSEC3 + * RRs to prove it */ + + r = dns_transaction_has_positive_answer(t, NULL); + 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. */ + + r = dns_answer_contains_nsec_or_nsec3(t->answer); + if (r < 0) + return r; + if (r > 0) + return false; + + return true; +} + +static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { + int r; + + assert(t); + assert(rr); + + /* Check if the specified RR is the "primary" response, + * i.e. either matches the question precisely or is a + * CNAME/DNAME for it, or is any kind of NSEC/NSEC3 RR */ + + r = dns_resource_key_match_rr(t->key, rr, NULL); + if (r != 0) + return r; + + r = dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); + if (r != 0) + return r; + + if (rr->key->type == DNS_TYPE_NSEC3) { + const char *p; + + p = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_name_parent(&p); + if (r < 0) + return r; + if (r > 0) { + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), p); + if (r < 0) + return r; + if (r > 0) + return true; + } + } + + return rr->key->type == DNS_TYPE_NSEC; +} + +int dns_transaction_request_dnssec_keys(DnsTransaction *t) { + DnsResourceRecord *rr; + + int r; + + assert(t); + + /* + * Retrieve all auxiliary RRs for the answer we got, so that + * we can verify signatures or prove that RRs are rightfully + * unsigned. Specifically: + * + * - 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 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) + return 0; + + DNS_ANSWER_FOREACH(rr, t->answer) { + + if (dns_type_is_pseudo(rr->key->type)) + continue; + + switch (rr->key->type) { + + case DNS_TYPE_RRSIG: { + /* For each RRSIG we request the matching DNSKEY */ + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; + + /* If this RRSIG is about a DNSKEY RR and the + * signer is the same as the owner, then we + * already have the DNSKEY, and we don't have + * to look for more. */ + if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { + r = dns_name_equal(rr->rrsig.signer, DNS_RESOURCE_KEY_NAME(rr->key)); + if (r < 0) + return r; + if (r > 0) + continue; + } + + /* If the signer is not a parent of our + * original query, then this is about an + * auxiliary RRset, but not anything we asked + * for. In this case we aren't interested, + * because we don't want to request additional + * RRs for stuff we didn't really ask for, and + * also to avoid request loops, where + * additional RRs from one transaction result + * in another transaction whose additonal RRs + * point back to the original transaction, and + * we deadlock. */ + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), rr->rrsig.signer); + if (r < 0) + return r; + if (r == 0) + continue; + + dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); + if (!dnskey) + return -ENOMEM; + + log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", t->id, DNS_RESOURCE_KEY_NAME(rr->key), rr->rrsig.key_tag); + r = dns_transaction_request_dnssec_rr(t, dnskey); + if (r < 0) + return r; + break; + } + + case DNS_TYPE_DNSKEY: { + /* For each DNSKEY we request the matching DS */ + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; + + /* If the DNSKEY we are looking at is not for + * zone we are interested in, nor any of its + * parents, we aren't interested, and don't + * request it. After all, we don't want to end + * up in request loops, and want to keep + * additional traffic down. */ + + r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(t->key), DNS_RESOURCE_KEY_NAME(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, DNS_RESOURCE_KEY_NAME(rr->key)); + 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)); + r = dns_transaction_request_dnssec_rr(t, ds); + if (r < 0) + return r; + + 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; + + /* For an unsigned SOA or NS, try to acquire + * the matching DS RR, as we are at a zone cut + * then, and whether a DS exists tells us + * whether the zone is signed. Do so only if + * this RR matches our original question, + * however. */ + + r = dns_resource_key_match_rr(t->key, rr, NULL); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, DNS_RESOURCE_KEY_NAME(rr->key)); + if (!ds) + return -ENOMEM; + + log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", t->id, DNS_RESOURCE_KEY_NAME(rr->key)); + r = dns_transaction_request_dnssec_rr(t, ds); + if (r < 0) + return r; + + break; + } + + case DNS_TYPE_CNAME: + case DNS_TYPE_DNAME: { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; + const char *name; + + /* CNAMEs and DNAMEs cannot be located at a + * zone apex, hence ask for the parent SOA for + * unsigned CNAME/DNAME RRs, maybe that's the + * apex. But do all that only if this is + * actually a response to our original + * question. */ + + r = dns_transaction_is_primary_response(t, rr); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + name = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r == 0) + continue; + + soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); + 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)); + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + + break; + } + + 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 + * question. */ + + r = dns_transaction_is_primary_response(t, rr); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dnssec_has_rrsig(t->answer, rr->key); + if (r < 0) + return r; + if (r > 0) + continue; + + soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, DNS_RESOURCE_KEY_NAME(rr->key)); + 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)); + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + break; + }} + } + + /* Above, we requested everything necessary to validate what + * we got. Now, let's request what we need to validate what we + * didn't get... */ + + r = dns_transaction_has_unsigned_negative_answer(t); + if (r < 0) + return r; + if (r > 0) { + const char *name; + + name = DNS_RESOURCE_KEY_NAME(t->key); + + /* If this was a SOA or NS request, then this + * indicates that we are not at a zone apex, hence ask + * the parent name instead. If this was a DS request, + * then it's signed when the parent zone is signed, + * hence ask the parent in that case, too. */ + + if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS, DNS_TYPE_DS)) { + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r > 0) + log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS/DS response).", t->id, DNS_RESOURCE_KEY_NAME(t->key)); + else + name = NULL; + } else + log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", t->id, DNS_RESOURCE_KEY_NAME(t->key)); + + if (name) { + _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; + + soa = dns_resource_key_new(t->key->class, DNS_TYPE_SOA, name); + if (!soa) + return -ENOMEM; + + r = dns_transaction_request_dnssec_rr(t, soa); + if (r < 0) + return r; + } + } + + return dns_transaction_dnssec_is_live(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) { + + 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); +} + +static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { + DnsResourceRecord *rr; + int ifindex, r; + + assert(t); + + /* Add all DNSKEY RRs from the answer that are validated by DS + * RRs from the list of validated keys to the list of + * validated keys. */ + + DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { + + r = dnssec_verify_dnskey_search(rr, t->validated_keys); + if (r < 0) + return r; + if (r == 0) + continue; + + /* If so, the DNSKEY is validated too. */ + r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + return 0; +} + +static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { + int r; + + assert(t); + assert(rr); + + /* 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) + return false; + + if (dns_type_is_pseudo(rr->key->type)) + return -EINVAL; + + switch (rr->key->type) { + + 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; + + case DNS_TYPE_RRSIG: + /* RRSIGs are the signatures themselves, they need no signing. */ + return false; + + case DNS_TYPE_SOA: + case DNS_TYPE_NS: { + DnsTransaction *dt; + Iterator i; + + /* For SOA or NS RRs we look for a matching DS transaction, or a SOA transaction of the parent */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_DS) + continue; + + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), DNS_RESOURCE_KEY_NAME(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + /* We found a DS transactions for the SOA/NS + * RRs we are looking at. If it discovered signed DS + * RRs, then we need to be signed, too. */ + + if (!dt->answer_authenticated) + return false; + + return dns_answer_match_key(dt->answer, dt->key, NULL); + } + + /* We found nothing that proves this is safe to leave + * this unauthenticated, hence ask inist on + * authentication. */ + return true; + } + + 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. */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_SOA) + continue; + + if (!parent) { + parent = DNS_RESOURCE_KEY_NAME(rr->key); + r = dns_name_parent(&parent); + if (r < 0) + return r; + if (r == 0) { + /* A CNAME/DNAME without a parent? That's sooo weird. */ + log_debug("Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); + return -EBADMSG; + } + } + + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), parent); + if (r < 0) + return r; + if (r == 0) + continue; + + return t->answer_authenticated; + } + + return true; + } + + default: { + DnsTransaction *dt; + Iterator i; + + /* Any other kind of RR. Let's see if our SOA lookup was authenticated */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != rr->key->class) + continue; + if (dt->key->type != DNS_TYPE_SOA) + continue; + + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), DNS_RESOURCE_KEY_NAME(rr->key)); + if (r < 0) + return r; + if (r == 0) + continue; + + /* We found the transaction that was supposed to find + * the SOA RR for us. It was successful, but found no + * RR for us. This means we are not at a zone cut. In + * this case, we require authentication if the SOA + * lookup was authenticated too. */ + return t->answer_authenticated; + } + + return true; + }} +} + +static int dns_transaction_requires_nsec(DnsTransaction *t) { + DnsTransaction *dt; + const char *name; + Iterator i; + int r; + + assert(t); + + /* Checks if we need to insist on NSEC/NSEC3 RRs for proving + * this negative reply */ + + if (t->scope->dnssec_mode != DNSSEC_YES) + return false; + + if (dns_type_is_pseudo(t->key->type)) + return -EINVAL; + + name = DNS_RESOURCE_KEY_NAME(t->key); + + if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS, DNS_TYPE_DS)) { + + /* We got a negative reply for this SOA/NS lookup? If + * so, then we are not at a zone apex, and thus should + * look at the result of the parent SOA lookup. + * + * We got a negative reply for this DS lookup? DS RRs + * are signed when their parent zone is signed, hence + * also check the parent SOA in this case. */ + + r = dns_name_parent(&name); + if (r < 0) + return r; + if (r == 0) + return true; + } + + /* For all other RRs we check the SOA on the same level to see + * if it's signed. */ + + SET_FOREACH(dt, t->dnssec_transactions, i) { + + if (dt->key->class != t->key->class) + continue; + if (dt->key->type != DNS_TYPE_SOA) + continue; + + r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dt->key), name); + if (r < 0) + return r; + if (r == 0) + continue; + + return dt->answer_authenticated; + } + + /* If in doubt, require NSEC/NSEC3 */ + return true; +} + +int dns_transaction_validate_dnssec(DnsTransaction *t) { + _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; + bool dnskeys_finalized = false; + DnsResourceRecord *rr; + DnsAnswerFlags flags; + int r; + + assert(t); + + /* We have now collected all DS and DNSKEY RRs in + * t->validated_keys, let's see which RRs we can now + * authenticate with that. */ + + if (t->scope->dnssec_mode != DNSSEC_YES) + return 0; + + /* Already validated */ + if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) + return 0; + + /* Our own stuff needs no validation */ + if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_authenticated = true; + return 0; + } + + /* Cached stuff is not affected by validation. */ + if (t->answer_source != DNS_TRANSACTION_NETWORK) + 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. */ + r = dns_transaction_validate_dnskey_by_ds(t); + if (r < 0) + return r; + + for (;;) { + bool changed = false; + + DNS_ANSWER_FOREACH(rr, t->answer) { + DnssecResult result; + + if (rr->key->type == DNS_TYPE_RRSIG) + continue; + + r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result); + if (r < 0) + return r; + + if (log_get_max_level() >= LOG_DEBUG) { + _cleanup_free_ char *rrs = NULL; + + (void) dns_resource_record_to_string(rr, &rrs); + log_debug("Looking at %s: %s", rrs ? strstrip(rrs) : "???", dnssec_result_to_string(result)); + } + + if (result == DNSSEC_VALIDATED) { + + if (rr->key->type == DNS_TYPE_DNSKEY) { + /* If we just validated a + * DNSKEY RRset, then let's + * add these keys to the set + * of validated keys for this + * transaction. */ + + r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); + if (r < 0) + return r; + } + + /* Add the validated RRset to the new + * list of validated RRsets, and + * remove it from the unvalidated + * RRsets. We mark the RRset as + * authenticated and cacheable. */ + r = dns_answer_move_by_key(&validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); + if (r < 0) + return r; + + /* Exit the loop, we dropped something from the answer, start from the beginning */ + changed = true; + break; + + } 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_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; + + changed = true; + break; + } + } + + r = dns_transaction_is_primary_response(t, rr); + 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; + } + + /* 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; + } + } + + 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; + continue; + } + + /* We're done */ + break; + } + + dns_answer_unref(t->answer); + t->answer = validated; + validated = NULL; + + /* At this point the answer only contains validated + * RRsets. Now, let's see if it actually answers the question + * we asked. If so, great! If it doesn't, then see if + * NSEC/NSEC3 can prove this. */ + r = dns_transaction_has_positive_answer(t, &flags); + if (r > 0) { + /* Yes, it answers the question! */ + + if (flags & DNS_ANSWER_AUTHENTICATED) { + /* The answer is fully authenticated, yay. */ + t->answer_dnssec_result = DNSSEC_VALIDATED; + t->answer_rcode = DNS_RCODE_SUCCESS; + t->answer_authenticated = true; + } else { + /* The answer is not fully authenticated. */ + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + } + + } else if (r == 0) { + DnssecNsecResult nr; + + /* Bummer! Let's check NSEC/NSEC3 */ + r = dnssec_test_nsec(t->answer, t->key, &nr); + if (r < 0) + return r; + + switch (nr) { + + case DNSSEC_NSEC_NXDOMAIN: + /* NSEC proves the domain doesn't exist. Very good. */ + 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; + break; + + case DNSSEC_NSEC_NODATA: + /* NSEC proves that there's no data here, very good. */ + 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; + break; + + case DNSSEC_NSEC_OPTOUT: + /* NSEC3 says the data might not be signed */ + log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, dns_transaction_key_string(t)); + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + break; + + case DNSSEC_NSEC_NO_RR: + /* No NSEC data? Bummer! */ + + r = dns_transaction_requires_nsec(t); + if (r < 0) + return r; + if (r > 0) + t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; + else { + t->answer_dnssec_result = DNSSEC_UNSIGNED; + t->answer_authenticated = false; + } + + break; + + case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: + /* We don't know the NSEC3 algorithm used? */ + t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; + break; + + case DNSSEC_NSEC_FOUND: + /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ + t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; + break; + + default: + assert_not_reached("Unexpected NSEC result."); + } + } + + return 1; +} + +const char *dns_transaction_key_string(DnsTransaction *t) { + assert(t); + + if (!t->key_string) { + if (dns_resource_key_to_string(t->key, &t->key_string) < 0) + return "n/a"; + } + + return strstrip(t->key_string); } static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { [DNS_TRANSACTION_NULL] = "null", [DNS_TRANSACTION_PENDING] = "pending", - [DNS_TRANSACTION_FAILURE] = "failure", + [DNS_TRANSACTION_VALIDATING] = "validating", + [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", [DNS_TRANSACTION_SUCCESS] = "success", [DNS_TRANSACTION_NO_SERVERS] = "no-servers", [DNS_TRANSACTION_TIMEOUT] = "timeout", @@ -834,6 +2117,7 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", [DNS_TRANSACTION_RESOURCES] = "resources", [DNS_TRANSACTION_ABORTED] = "aborted", + [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", }; DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); |