diff --git a/doc/unbound.conf.5.in b/doc/unbound.conf.5.in index f426ac5f..147fbfa9 100644 --- a/doc/unbound.conf.5.in +++ b/doc/unbound.conf.5.in @@ -872,6 +872,13 @@ potentially broken nameservers. A lot of domains will not be resolvable when this option in enabled. Only use if you know what you are doing. This option only has effect when qname-minimisation is enabled. Default is no. .TP +.B aaaa\-filter: \fI +Activate behavior similar to BIND's AAAA-filter. +This forces the dropping of all AAAA records, unless in the case of +explicit AAAA queries, when no A records have been confirmed. +This also causes an additional A query to be sent for each AAAA query. +This breaks DNSSEC! +.TP .B aggressive\-nsec: \fI Aggressive NSEC uses the DNSSEC NSEC chain to synthesize NXDOMAIN and other denials, using information from previous NXDOMAINs answers. diff --git a/iterator/iter_scrub.c b/iterator/iter_scrub.c index aae934dd..55c55de0 100644 --- a/iterator/iter_scrub.c +++ b/iterator/iter_scrub.c @@ -667,6 +667,32 @@ static int sanitize_nsec_is_overreach(struct rrset_parse* rrset, return 0; } +/** + * ASN: Lookup A records from rrset cache. + * @param qinfo: the question originally asked. + * @param env: module environment with config and cache. + * @param ie: iterator environment with private address data. + * @return 0 if no A record found, 1 if A record found. + */ +static int +asn_lookup_a_record_from_cache(struct query_info* qinfo, + struct module_env* env, struct iter_env* ATTR_UNUSED(ie)) +{ + struct ub_packed_rrset_key* akey; + + /* get cached A records for queried name */ + akey = rrset_cache_lookup(env->rrset_cache, qinfo->qname, + qinfo->qname_len, LDNS_RR_TYPE_A, qinfo->qclass, + 0, *env->now, 0); + if(akey) { /* we had some. */ + log_rrset_key(VERB_ALGO, "ASN-AAAA-filter: found A record", + akey); + lock_rw_unlock(&akey->entry.lock); + return 1; + } + return 0; +} + /** * Given a response event, remove suspect RRsets from the response. * "Suspect" rrsets are potentially poison. Note that this routine expects @@ -686,6 +712,7 @@ scrub_sanitize(sldns_buffer* pkt, struct msg_parse* msg, struct query_info* qinfo, uint8_t* zonename, struct module_env* env, struct iter_env* ie) { + int found_a_record = 0; /* ASN: do we have a A record? */ int del_addi = 0; /* if additional-holding rrsets are deleted, we do not trust the normalized additional-A-AAAA any more */ struct rrset_parse* rrset, *prev; @@ -721,6 +748,13 @@ scrub_sanitize(sldns_buffer* pkt, struct msg_parse* msg, rrset = rrset->rrset_all_next; } + /* ASN: Locate any A record we can find */ + if((ie->aaaa_filter) && (qinfo->qtype == LDNS_RR_TYPE_AAAA)) { + found_a_record = asn_lookup_a_record_from_cache(qinfo, + env, ie); + } + /* ASN: End of added code */ + /* At this point, we brutally remove ALL rrsets that aren't * children of the originating zone. The idea here is that, * as far as we know, the server that we contacted is ONLY @@ -732,6 +766,24 @@ scrub_sanitize(sldns_buffer* pkt, struct msg_parse* msg, rrset = msg->rrset_first; while(rrset) { + /* ASN: For AAAA records only... */ + if((ie->aaaa_filter) && (rrset->type == LDNS_RR_TYPE_AAAA)) { + /* ASN: If this is not a AAAA query, then remove AAAA + * records, no questions asked. If this IS a AAAA query + * then remove AAAA records if we have an A record. + * Otherwise, leave things be. */ + if((qinfo->qtype != LDNS_RR_TYPE_AAAA) || + (found_a_record)) { + remove_rrset("ASN-AAAA-filter: removing AAAA " + "for record", pkt, msg, prev, &rrset); + continue; + } + log_nametypeclass(VERB_ALGO, "ASN-AAAA-filter: " + "keep AAAA for", zonename, + LDNS_RR_TYPE_AAAA, qinfo->qclass); + } + /* ASN: End of added code */ + /* remove private addresses */ if( (rrset->type == LDNS_RR_TYPE_A || rrset->type == LDNS_RR_TYPE_AAAA)) { diff --git a/iterator/iter_utils.c b/iterator/iter_utils.c index 7bc67da6..e10f547a 100644 --- a/iterator/iter_utils.c +++ b/iterator/iter_utils.c @@ -175,6 +175,7 @@ iter_apply_cfg(struct iter_env* iter_env, struct config_file* cfg) } iter_env->supports_ipv6 = cfg->do_ip6; iter_env->supports_ipv4 = cfg->do_ip4; + iter_env->aaaa_filter = cfg->aaaa_filter; return 1; } diff --git a/iterator/iterator.c b/iterator/iterator.c index 23b07ea9..ca29b48c 100644 --- a/iterator/iterator.c +++ b/iterator/iterator.c @@ -2127,6 +2127,53 @@ processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id) return 0; } + +/** + * ASN: This event state was added as an intermediary step between + * QUERYTARGETS_STATE and the next step, in order to cast a subquery for the + * purpose of caching A records for the queried name. + * + * @param qstate: query state. + * @param iq: iterator query state. + * @param ie: iterator shared global environment. + * @param id: module id. + * @return true if the event requires more request processing immediately, + * false if not. This state only returns true when it is generating + * a SERVFAIL response because the query has hit a dead end. + */ +static int +asn_processQueryAAAA(struct module_qstate* qstate, struct iter_qstate* iq, + struct iter_env* ATTR_UNUSED(ie), int id) +{ + struct module_qstate* subq = NULL; + + log_assert(iq->fetch_a_for_aaaa == 0); + + /* flag the query properly in order to not loop */ + iq->fetch_a_for_aaaa = 1; + + /* re-throw same query, but with a different type */ + if(!generate_sub_request(iq->qchase.qname, + iq->qchase.qname_len, LDNS_RR_TYPE_A, + iq->qchase.qclass, qstate, id, iq, + INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1, 0)) { + log_nametypeclass(VERB_ALGO, "ASN-AAAA-filter: failed " + "preloading of A record for", + iq->qchase.qname, LDNS_RR_TYPE_A, + iq->qchase.qclass); + return error_response(qstate, id, LDNS_RCODE_SERVFAIL); + } + log_nametypeclass(VERB_ALGO, "ASN-AAAA-filter: " + "preloading records in cache for", + iq->qchase.qname, LDNS_RR_TYPE_A, + iq->qchase.qclass); + + /* set this query as waiting */ + qstate->ext_state[id] = module_wait_subquery; + /* at this point break loop */ + return 0; +} +/* ASN: End of added code */ /** * This is the request event state where the request will be sent to one of @@ -2186,6 +2233,13 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq, return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } + /* ASN: If we have a AAAA query, then also query for A records */ + if((ie->aaaa_filter) && (iq->qchase.qtype == LDNS_RR_TYPE_AAAA) && + (iq->fetch_a_for_aaaa == 0)) { + return next_state(iq, ASN_FETCH_A_FOR_AAAA_STATE); + } + /* ASN: End of added code */ + /* Make sure we have a delegation point, otherwise priming failed * or another failure occurred */ if(!iq->dp) { @@ -3574,6 +3628,61 @@ processFinished(struct module_qstate* qstate, struct iter_qstate* iq, return 0; } +/** + * ASN: Do final processing on responses to A queries originated from AAAA + * queries. Events reach this state after the iterative resolution algorithm + * terminates. + * This is required down the road to decide whether to scrub AAAA records + * from the results or not. + * + * @param qstate: query state. + * @param id: module id. + * @param forq: super query state. + */ +static void +asn_processAAAAResponse(struct module_qstate* qstate, int id, + struct module_qstate* super) +{ + /*struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id];*/ + struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id]; + struct delegpt_ns* dpns = NULL; + int error = (qstate->return_rcode != LDNS_RCODE_NOERROR); + + log_assert(super_iq->fetch_a_for_aaaa > 0); + + /* let super go to evaluation of targets after this */ + super_iq->state = QUERYTARGETS_STATE; + + log_query_info(VERB_ALGO, "ASN-AAAA-filter: processAAAAResponse", + &qstate->qinfo); + log_query_info(VERB_ALGO, "ASN-AAAA-filter: processAAAAResponse super", + &super->qinfo); + + if(super_iq->dp) + dpns = delegpt_find_ns(super_iq->dp, + qstate->qinfo.qname, qstate->qinfo.qname_len); + if (!dpns) { + /* not interested */ + verbose(VERB_ALGO, "ASN-AAAA-filter: subq: %s, but parent not " + "interested%s", (error ? "error, but" : "success"), + (super_iq->dp ? "anymore" : " (was reset)")); + log_query_info(VERB_ALGO, "ASN-AAAA-filter: superq", &super->qinfo); + if(super_iq->dp && error) + delegpt_log(VERB_ALGO, super_iq->dp); + return; + } else if (error) { + verbose(VERB_ALGO, "ASN-AAAA-filter: mark as failed, " + "and go to target query."); + /* see if the failure did get (parent-lame) info */ + if(!cache_fill_missing(super->env, + super_iq->qchase.qclass, super->region, + super_iq->dp)) + log_err("ASN-AAAA-filter: out of memory adding missing"); + dpns->resolved = 1; /* mark as failed */ + } +} +/* ASN: End of added code */ + /* * Return priming query results to interested super querystates. * @@ -3593,6 +3702,9 @@ iter_inform_super(struct module_qstate* qstate, int id, else if(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*) super->minfo[id])->state == DSNS_FIND_STATE) processDSNSResponse(qstate, id, super); + else if (super->qinfo.qtype == LDNS_RR_TYPE_AAAA && ((struct iter_qstate*) + super->minfo[id])->state == ASN_FETCH_A_FOR_AAAA_STATE) + asn_processAAAAResponse(qstate, id, super); else if(qstate->return_rcode != LDNS_RCODE_NOERROR) error_supers(qstate, id, super); else if(qstate->is_priming) @@ -3630,6 +3742,9 @@ iter_handle(struct module_qstate* qstate, struct iter_qstate* iq, case INIT_REQUEST_3_STATE: cont = processInitRequest3(qstate, iq, id); break; + case ASN_FETCH_A_FOR_AAAA_STATE: + cont = asn_processQueryAAAA(qstate, iq, ie, id); + break; case QUERYTARGETS_STATE: cont = processQueryTargets(qstate, iq, ie, id); break; @@ -3961,6 +4076,8 @@ iter_state_to_string(enum iter_state state) return "INIT REQUEST STATE (stage 2)"; case INIT_REQUEST_3_STATE: return "INIT REQUEST STATE (stage 3)"; + case ASN_FETCH_A_FOR_AAAA_STATE: + return "ASN_FETCH_A_FOR_AAAA_STATE"; case QUERYTARGETS_STATE : return "QUERY TARGETS STATE"; case PRIME_RESP_STATE : @@ -3985,6 +4102,7 @@ iter_state_is_responsestate(enum iter_state s) case INIT_REQUEST_STATE : case INIT_REQUEST_2_STATE : case INIT_REQUEST_3_STATE : + case ASN_FETCH_A_FOR_AAAA_STATE : case QUERYTARGETS_STATE : case COLLECT_CLASS_STATE : return 0; diff --git a/iterator/iterator.h b/iterator/iterator.h index 342ac207..731948d1 100644 --- a/iterator/iterator.h +++ b/iterator/iterator.h @@ -135,6 +135,9 @@ struct iter_env { */ int* target_fetch_policy; + /** ASN: AAAA-filter flag */ + int aaaa_filter; + /** lock on ratelimit counter */ lock_basic_type queries_ratelimit_lock; /** number of queries that have been ratelimited */ @@ -186,6 +189,14 @@ enum iter_state { */ INIT_REQUEST_3_STATE, + /** + * This state is responsible for intercepting AAAA queries, + * and launch a A subquery on the same target, to populate the + * cache with A records, so the AAAA filter scrubbing logic can + * work. + */ + ASN_FETCH_A_FOR_AAAA_STATE, + /** * Each time a delegation point changes for a given query or a * query times out and/or wakes up, this state is (re)visited. @@ -375,6 +386,13 @@ struct iter_qstate { */ int refetch_glue; + /** + * ASN: This is a flag that, if true, means that this query is + * for fetching A records to populate cache and determine if we must + * return AAAA records or not. + */ + int fetch_a_for_aaaa; + /** list of pending queries to authoritative servers. */ struct outbound_list outlist; diff --git a/pythonmod/interface.i b/pythonmod/interface.i index f08b575d..47f1bb2e 100644 --- a/pythonmod/interface.i +++ b/pythonmod/interface.i @@ -975,6 +975,7 @@ struct config_file { int harden_dnssec_stripped; int harden_referral_path; int use_caps_bits_for_id; + int aaaa_filter; /* ASN */ struct config_strlist* private_address; struct config_strlist* private_domain; size_t unwanted_threshold; diff --git a/util/config_file.c b/util/config_file.c index 0ab8614a..729fb147 100644 --- a/util/config_file.c +++ b/util/config_file.c @@ -218,6 +218,7 @@ config_create(void) cfg->harden_referral_path = 0; cfg->harden_algo_downgrade = 0; cfg->use_caps_bits_for_id = 0; + cfg->aaaa_filter = 0; /* ASN: default is disabled */ cfg->caps_whitelist = NULL; cfg->private_address = NULL; cfg->private_domain = NULL; diff --git a/util/config_file.h b/util/config_file.h index e61257a3..dabaa7bb 100644 --- a/util/config_file.h +++ b/util/config_file.h @@ -260,6 +260,8 @@ struct config_file { int harden_algo_downgrade; /** use 0x20 bits in query as random ID bits */ int use_caps_bits_for_id; + /** ASN: enable AAAA filter? */ + int aaaa_filter; /** 0x20 whitelist, domains that do not use capsforid */ struct config_strlist* caps_whitelist; /** strip away these private addrs from answers, no DNS Rebinding */ diff --git a/util/configlexer.lex b/util/configlexer.lex index 79a0edca..4eaec678 100644 --- a/util/configlexer.lex +++ b/util/configlexer.lex @@ -304,6 +304,7 @@ harden-algo-downgrade{COLON} { YDVAR(1, VAR_HARDEN_ALGO_DOWNGRADE) } use-caps-for-id{COLON} { YDVAR(1, VAR_USE_CAPS_FOR_ID) } caps-whitelist{COLON} { YDVAR(1, VAR_CAPS_WHITELIST) } unwanted-reply-threshold{COLON} { YDVAR(1, VAR_UNWANTED_REPLY_THRESHOLD) } +aaaa-filter{COLON} { YDVAR(1, VAR_AAAA_FILTER) } private-address{COLON} { YDVAR(1, VAR_PRIVATE_ADDRESS) } private-domain{COLON} { YDVAR(1, VAR_PRIVATE_DOMAIN) } prefetch-key{COLON} { YDVAR(1, VAR_PREFETCH_KEY) } diff --git a/util/configparser.y b/util/configparser.y index 1d0e8658..f284dd43 100644 --- a/util/configparser.y +++ b/util/configparser.y @@ -97,6 +97,7 @@ extern struct config_parser_state* cfg_parser; %token VAR_STATISTICS_CUMULATIVE VAR_OUTGOING_PORT_PERMIT %token VAR_OUTGOING_PORT_AVOID VAR_DLV_ANCHOR_FILE VAR_DLV_ANCHOR %token VAR_NEG_CACHE_SIZE VAR_HARDEN_REFERRAL_PATH VAR_PRIVATE_ADDRESS +%token VAR_AAAA_FILTER %token VAR_PRIVATE_DOMAIN VAR_REMOTE_CONTROL VAR_CONTROL_ENABLE %token VAR_CONTROL_INTERFACE VAR_CONTROL_PORT VAR_SERVER_KEY_FILE %token VAR_SERVER_CERT_FILE VAR_CONTROL_KEY_FILE VAR_CONTROL_CERT_FILE @@ -233,6 +234,7 @@ content_server: server_num_threads | server_verbosity | server_port | server_dlv_anchor_file | server_dlv_anchor | server_neg_cache_size | server_harden_referral_path | server_private_address | server_private_domain | server_extended_statistics | + server_aaaa_filter | server_local_data_ptr | server_jostle_timeout | server_unwanted_reply_threshold | server_log_time_ascii | server_domain_insecure | server_val_sig_skew_min | @@ -1563,6 +1565,15 @@ server_caps_whitelist: VAR_CAPS_WHITELIST STRING_ARG yyerror("out of memory"); } ; +server_aaaa_filter: VAR_AAAA_FILTER STRING_ARG + { + OUTYY(("P(server_aaaa_filter:%s)\n", $2)); + if(strcmp($2, "yes") != 0 && strcmp($2, "no") != 0) + yyerror("expected yes or no."); + else cfg_parser->cfg->aaaa_filter = (strcmp($2, "yes")==0); + free($2); + } + ; server_private_address: VAR_PRIVATE_ADDRESS STRING_ARG { OUTYY(("P(server_private_address:%s)\n", $2));