diff options
Diffstat (limited to 'src/resolve/resolved-dns-transaction.c')
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 841 |
1 files changed, 736 insertions, 105 deletions
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 8b3e59a1ea..347b1683f9 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -80,6 +80,7 @@ DnsTransaction* dns_transaction_free(DnsTransaction *t) { dns_answer_unref(t->validated_keys); + free(t->key_string); free(t); return NULL; } @@ -128,7 +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->dnssec_result = _DNSSEC_RESULT_INVALID; + t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; t->key = dns_resource_key_ref(key); /* Find a fresh, unused transaction id */ @@ -182,7 +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), @@ -225,12 +228,15 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { * 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; @@ -239,14 +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->notify_query_candidates, i) dns_query_candidate_notify(c); SET_FOREACH(z, t->notify_zone_items, i) dns_zone_item_notify(z); - SET_FOREACH(d, t->notify_transactions, i) - dns_transaction_notify(d, t); - t->block_gc--; + 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); } @@ -351,7 +385,6 @@ static int dns_transaction_open_tcp(DnsTransaction *t) { t->server = dns_server_ref(server); t->received = dns_packet_unref(t->received); t->answer = dns_answer_unref(t->answer); - t->n_answer_cacheable = 0; t->answer_rcode = 0; t->stream->complete = on_stream_complete; t->stream->transaction = t; @@ -394,20 +427,32 @@ static void dns_transaction_cache_answer(DnsTransaction *t) { t->key, t->answer_rcode, t->answer, - t->n_answer_cacheable, 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 (!set_isempty(t->dnssec_transactions)) + if (dns_transaction_dnssec_is_live(t)) return; /* All our auxiliary DNSSEC transactions are complete now. Try @@ -418,7 +463,10 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) { return; } - if (!IN_SET(t->dnssec_result, _DNSSEC_RESULT_INVALID, DNSSEC_VALIDATED, DNSSEC_NO_SIGNATURE /* FOR NOW! */)) { + 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; } @@ -428,7 +476,7 @@ static void dns_transaction_process_dnssec(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); } void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { @@ -606,16 +654,7 @@ 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_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. However, - * if we know the message is authenticated, we might - * as well cache everything. */ - if (t->answer_authenticated) - t->n_answer_cacheable = (unsigned) -1; /* everything! */ - else - t->n_answer_cacheable = DNS_PACKET_ANCOUNT(t->received); /* only the answer section */ + t->answer_authenticated = false; r = dns_transaction_request_dnssec_keys(t); if (r < 0) { @@ -625,6 +664,7 @@ 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); return; } } @@ -714,6 +754,8 @@ static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdat 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); @@ -769,7 +811,6 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { t->start_usec = ts; t->received = dns_packet_unref(t->received); t->answer = dns_answer_unref(t->answer); - t->n_answer_cacheable = 0; t->answer_rcode = 0; t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; @@ -823,7 +864,7 @@ static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { 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; } } @@ -843,7 +884,7 @@ static int dns_transaction_make_packet_mdns(DnsTransaction *t) { assert(t); assert(t->scope->protocol == DNS_PROTOCOL_MDNS); - /* Discard any previously prepared packet, so we can start over and coaleasce again */ + /* 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); @@ -980,17 +1021,12 @@ int dns_transaction_go(DnsTransaction *t) { if (r <= 0) return r; - if (log_get_max_level() >= LOG_DEBUG) { - _cleanup_free_ char *ks = NULL; - - (void) dns_resource_key_to_string(t->key, &ks); - - log_debug("Excercising transaction for <%s> on scope %s on %s/%s", - ks ? strstrip(ks) : "???", - 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)); - } + 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 || @@ -1149,6 +1185,12 @@ 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); if (r < 0) @@ -1175,17 +1217,118 @@ static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey * 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: { @@ -1204,10 +1347,18 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) { continue; } - /* If the signer is not a parent of the owner, - * then the signature is bogus, let's ignore - * it. */ - r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), rr->rrsig.signer); + /* 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) @@ -1217,8 +1368,7 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) { if (!dnskey) return -ENOMEM; - log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (key tag: %" PRIu16 ").", t->id, rr->rrsig.key_tag); - + 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; @@ -1229,76 +1379,260 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) { /* 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" (key tag: %" PRIu16 ").", t->id, 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)); + 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; }} } - return !set_isempty(t->dnssec_transactions); + /* 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(IN_SET(t->state, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)); 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 simply copy the answer from that - transaction over. */ + completed its work. We copy any RRs from that transaction + over into our list of validated keys -- but only if the + answer is authenticated. - if (source->state != DNS_TRANSACTION_SUCCESS) { - log_debug("Auxiliary DNSSEC RR query failed."); - t->dnssec_result = DNSSEC_FAILED_AUXILIARY; - } else { - r = dns_answer_extend(&t->validated_keys, source->answer); - if (r < 0) { - log_error_errno(r, "Failed to merge validated DNSSEC key data: %m"); - t->dnssec_result = DNSSEC_FAILED_AUXILIARY; - } - } + 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. */ - /* Detach us from the DNSSEC transaction. */ - (void) set_remove(t->dnssec_transactions, source); - (void) set_remove(source->notify_transactions, t); + switch (source->state) { - /* 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); -} + case DNS_TRANSACTION_DNSSEC_FAILED: -static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { - int r; + 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; - assert(t); - assert(rr); + case DNS_TRANSACTION_RCODE_FAILURE: - /* Check if the specified RR is the "primary" response, - * i.e. either matches the question precisely or is a - * CNAME/DNAME for it */ + if (source->answer_rcode != DNS_RCODE_NXDOMAIN) { + log_debug("Auxiliary DNSSEC RR query failed with rcode=%i.", source->answer_rcode); + goto fail; + } - r = dns_resource_key_match_rr(t->key, rr, NULL); - if (r != 0) - return r; + /* fall-through: NXDOMAIN is good enough for us */ - r = dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); - if (r != 0) - return r; + 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; + } + } - return 0; + /* 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) { @@ -1308,8 +1642,8 @@ static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { assert(t); /* Add all DNSKEY RRs from the answer that are validated by DS - * RRs from the list of validated keys to the lis of validated - * keys. */ + * RRs from the list of validated keys to the list of + * validated keys. */ DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { @@ -1320,7 +1654,7 @@ static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { continue; /* If so, the DNSKEY is validated too. */ - r = dns_answer_add_extend(&t->validated_keys, rr, ifindex); + r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); if (r < 0) return r; } @@ -1328,10 +1662,204 @@ static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { 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); @@ -1344,21 +1872,21 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { return 0; /* Already validated */ - if (t->dnssec_result != _DNSSEC_RESULT_INVALID) + 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->dnssec_result = DNSSEC_VALIDATED; + t->answer_dnssec_result = DNSSEC_VALIDATED; t->answer_authenticated = true; return 0; } - if (log_get_max_level() >= LOG_DEBUG) { - _cleanup_free_ char *ks = NULL; + /* Cached stuff is not affected by validation. */ + if (t->answer_source != DNS_TRANSACTION_NETWORK) + return 0; - (void) dns_resource_key_to_string(t->key, &ks); - log_debug("Validating response from transaction %" PRIu16 " (%s).", t->id, ks ? strstrip(ks) : "???"); - } + 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); @@ -1387,11 +1915,6 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (result == DNSSEC_VALIDATED) { - /* Add the validated RRset to the new list of validated RRsets */ - r = dns_answer_copy_by_key(&validated, t->answer, rr->key); - if (r < 0) - return r; - if (rr->key->type == DNS_TYPE_DNSKEY) { /* If we just validated a * DNSKEY RRset, then let's @@ -1399,13 +1922,17 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { * of validated keys for this * transaction. */ - r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key); + r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); if (r < 0) return r; } - /* Now, remove this RRset from the RRs still to process */ - r = dns_answer_remove_by_key(&t->answer, rr->key); + /* 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; @@ -1419,6 +1946,22 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { * 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; @@ -1427,7 +1970,7 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { * to our question, and it * failed validation. That's * fatal. */ - t->dnssec_result = result; + t->answer_dnssec_result = result; return 0; } @@ -1466,19 +2009,107 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { t->answer = validated; validated = NULL; - /* Everything that's now in t->answer is known to be good, hence cacheable. */ - t->n_answer_cacheable = (unsigned) -1; /* everything! */ + /* 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."); + } + } - t->answer_authenticated = true; - t->dnssec_result = DNSSEC_VALIDATED; 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_VALIDATING] = "validating", - [DNS_TRANSACTION_FAILURE] = "failure", + [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", [DNS_TRANSACTION_SUCCESS] = "success", [DNS_TRANSACTION_NO_SERVERS] = "no-servers", [DNS_TRANSACTION_TIMEOUT] = "timeout", |