diff options
Diffstat (limited to 'src/resolve/resolved-dns-transaction.c')
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 471 |
1 files changed, 345 insertions, 126 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 347b1683f9..fb95554db3 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -29,6 +29,31 @@ #include "resolved-llmnr.h" #include "string-table.h" +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; +} + +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 +62,13 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) { if (!t) return NULL; - sd_event_source_unref(t->timeout_event_source); + dns_transaction_close_connection(t); + dns_transaction_stop_timeout(t); dns_packet_unref(t->sent); - dns_packet_unref(t->received); - - dns_answer_unref(t->answer); - - sd_event_source_unref(t->dns_udp_event_source); - safe_close(t->dns_udp_fd); + 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 +78,6 @@ 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); @@ -79,8 +97,9 @@ DnsTransaction* dns_transaction_free(DnsTransaction *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; } @@ -153,6 +172,8 @@ 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; @@ -161,16 +182,6 @@ int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) return 0; } -static void dns_transaction_stop(DnsTransaction *t) { - assert(t); - - t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); - t->stream = dns_stream_free(t->stream); - - /* Note that we do not drop the UDP socket here, as we want to - * reuse it to repeat the interaction. */ -} - static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { _cleanup_free_ char *pretty = NULL; DnsZoneItem *z; @@ -224,6 +235,14 @@ 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("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 +259,8 @@ 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 +304,27 @@ 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_features = 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 int on_stream_complete(DnsStream *s, int error) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsTransaction *t; @@ -298,6 +339,11 @@ static int on_stream_complete(DnsStream *s, int error) { t->stream = dns_stream_free(t->stream); + if (IN_SET(error, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE)) { + dns_transaction_complete(t, DNS_TRANSACTION_CONNECTION_FAILURE); + return 0; + } + if (error != 0) { dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); return 0; @@ -315,32 +361,43 @@ 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; + + r = dns_server_adjust_opt(t->server, t->sent, t->current_features); + 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 +414,7 @@ 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 +429,6 @@ 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 +437,6 @@ 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 +446,11 @@ 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->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); + t->tried_stream = true; - dns_scope_next_dns_server(t->scope); + return 0; } static void dns_transaction_cache_answer(DnsTransaction *t) { @@ -463,10 +508,19 @@ 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 +539,12 @@ 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. */ @@ -618,16 +674,16 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { } /* On DNS, couldn't send? Try immediately again, with a new server */ - dns_transaction_next_dns_server(t); + dns_scope_next_dns_server(t->scope); r = dns_transaction_go(t); if (r < 0) { dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); return; } - - return; } + + return; } /* Parse message, if it isn't parsed yet. */ @@ -654,6 +710,7 @@ 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; r = dns_transaction_request_dnssec_keys(t); @@ -664,7 +721,8 @@ 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; } } @@ -688,39 +746,54 @@ 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, ignoring."); + log_debug("Invalid DNS UDP packet, ignoring."); 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_features < DNS_SERVER_FEATURE_LEVEL_UDP) + return -EAGAIN; + + 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 = 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; + } - r = dns_scope_emit(t->scope, t->dns_udp_fd, t->server, t->sent); + t->dns_udp_fd = fd; + } + + r = dns_server_adjust_opt(t->server, t->sent, t->current_features); + 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; } @@ -735,17 +808,17 @@ 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); - 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."); } @@ -757,7 +830,7 @@ 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); + dns_scope_next_dns_server(t->scope); r = dns_transaction_go(t); if (r < 0) @@ -771,36 +844,36 @@ 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); @@ -809,10 +882,8 @@ 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); /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ if (t->scope->protocol == DNS_PROTOCOL_DNS) { @@ -986,7 +1057,7 @@ 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 +1112,12 @@ 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; @@ -1093,7 +1166,7 @@ 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 || r == -EAGAIN) r = dns_transaction_open_tcp(t); } @@ -1109,7 +1182,7 @@ int dns_transaction_go(DnsTransaction *t) { } /* 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); } @@ -1315,15 +1388,20 @@ 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->current_features < DNS_SERVER_FEATURE_LEVEL_DO) + return 0; /* Server doesn't do DNSSEC, there's no point in requesting any RRs then. */ + if (t->server && t->server->rrsig_missing) + return 0; /* Server handles DNSSEC requests, but isn't augmenting responses with RRSIGs. No point in trying DNSSEC then. */ + DNS_ANSWER_FOREACH(rr, t->answer) { if (dns_type_is_pseudo(rr->key->type)) @@ -1404,15 +1482,6 @@ 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 +1517,7 @@ 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 +1528,10 @@ 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) @@ -1483,7 +1556,7 @@ 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 +1567,11 @@ 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 +1590,7 @@ 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; @@ -1671,7 +1745,7 @@ 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)) @@ -1679,13 +1753,6 @@ static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord * 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; @@ -1695,7 +1762,7 @@ 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 +1793,18 @@ 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 +1819,9 @@ 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 +1844,7 @@ 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) { @@ -1807,7 +1882,7 @@ 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)) @@ -1855,6 +1930,82 @@ 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). */ + + 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)); +} + int dns_transaction_validate_dnssec(DnsTransaction *t) { _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; bool dnskeys_finalized = false; @@ -1868,7 +2019,7 @@ 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 */ @@ -1886,6 +2037,13 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (t->answer_source != DNS_TRANSACTION_NETWORK) return 0; + if (t->current_features < DNS_SERVER_FEATURE_LEVEL_DO || + (t->server && t->server->rrsig_missing)) { + /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ + t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; + 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. */ @@ -1906,12 +2064,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { 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)); - } + log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); if (result == DNSSEC_VALIDATED) { @@ -1936,11 +2089,14 @@ 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; } else if (dnskeys_finalized) { + /* If we haven't read all DNSKEYs yet * a negative result of the validation * is irrelevant, as there might be @@ -1957,11 +2113,72 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (r < 0) return r; + 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); + + if (t->scope->dnssec_mode == DNSSEC_DOWNGRADE_OK) { + + /* 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; + } + } + + 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, + DNSSEC_UNSUPPORTED_ALGORITHM)) + t->scope->manager->n_dnssec_bogus++; + else + t->scope->manager->n_dnssec_indeterminate++; + r = dns_transaction_is_primary_response(t, rr); if (r < 0) return r; @@ -2030,9 +2247,10 @@ 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_test_nsec(t->answer, t->key, &nr, &authenticated); if (r < 0) return r; @@ -2043,7 +2261,7 @@ 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 +2269,7 @@ 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: @@ -2116,6 +2334,7 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", [DNS_TRANSACTION_RESOURCES] = "resources", + [DNS_TRANSACTION_CONNECTION_FAILURE] = "connection-failure", [DNS_TRANSACTION_ABORTED] = "aborted", [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", }; |