aaaa-filter-iterator.patch [plain text]
--- unbound-1.4.17.orig/doc/unbound.conf.5.in
+++ unbound-1.4.17/doc/unbound.conf.5.in
@@ -519,6 +519,13 @@ authority servers and checks if the repl
Disabled by default.
This feature is an experimental implementation of draft dns\-0x20.
.TP
+.B aaaa\-filter: \fI<yes or no>
+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 private\-address: \fI<IP address or subnet>
Give IPv4 of IPv6 addresses or classless subnets. These are addresses
on your private network, and are not allowed to be returned for public
--- unbound-1.4.17.orig/util/config_file.c
+++ unbound-1.4.17/util/config_file.c
@@ -160,6 +160,7 @@ config_create(void)
cfg->harden_below_nxdomain = 0;
cfg->harden_referral_path = 0;
cfg->use_caps_bits_for_id = 0;
+ cfg->aaaa_filter = 0; /* ASN: default is disabled */
cfg->private_address = NULL;
cfg->private_domain = NULL;
cfg->unwanted_threshold = 0;
--- unbound-1.4.17.orig/iterator/iter_scrub.c
+++ unbound-1.4.17/iterator/iter_scrub.c
@@ -580,6 +580,32 @@ static int sanitize_nsec_is_overreach(st
}
/**
+ * 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* 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
* the response to be in a "normalized" state -- that is, all "irrelevant"
@@ -598,6 +625,7 @@ scrub_sanitize(ldns_buffer* pkt, struct
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;
@@ -633,6 +661,13 @@ scrub_sanitize(ldns_buffer* pkt, struct
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
@@ -644,6 +679,24 @@ scrub_sanitize(ldns_buffer* pkt, struct
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) &&
--- unbound-1.4.17.orig/iterator/iterator.c
+++ unbound-1.4.17/iterator/iterator.c
@@ -1579,6 +1579,53 @@ processDSNSFind(struct module_qstate* qs
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* 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)) {
+ 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
@@ -1626,6 +1673,13 @@ processQueryTargets(struct module_qstate
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) {
@@ -2568,6 +2622,62 @@ processFinished(struct module_qstate* qs
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 ub_packed_rrset_key* rrset;
+ 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 interestes super querystates.
*
@@ -2587,6 +2697,9 @@ iter_inform_super(struct module_qstate*
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)
@@ -2624,6 +2737,9 @@ iter_handle(struct module_qstate* qstate
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;
@@ -2863,6 +2979,8 @@ iter_state_to_string(enum iter_state sta
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 :
@@ -2887,6 +3005,7 @@ iter_state_is_responsestate(enum iter_st
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;
--- unbound-1.4.17.orig/iterator/iter_utils.c
+++ unbound-1.4.17/iterator/iter_utils.c
@@ -128,6 +128,7 @@ iter_apply_cfg(struct iter_env* iter_env
}
iter_env->supports_ipv6 = cfg->do_ip6;
iter_env->supports_ipv4 = cfg->do_ip4;
+ iter_env->aaaa_filter = cfg->aaaa_filter;
return 1;
}
--- unbound-1.4.17.orig/iterator/iterator.h
+++ unbound-1.4.17/iterator/iterator.h
@@ -110,6 +110,9 @@ struct iter_env {
* array of max_dependency_depth+1 size.
*/
int* target_fetch_policy;
+
+ /** ASN: AAAA-filter flag */
+ int aaaa_filter;
};
/**
@@ -135,6 +138,14 @@ 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.
* This state is reponsible for iterating through a list of
@@ -309,6 +320,13 @@ 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;
};
--- unbound-1.4.17.orig/util/config_file.h
+++ unbound-1.4.17/util/config_file.h
@@ -169,6 +169,8 @@ struct config_file {
int harden_referral_path;
/** use 0x20 bits in query as random ID bits */
int use_caps_bits_for_id;
+ /** ASN: enable AAAA filter? */
+ int aaaa_filter;
/** strip away these private addrs from answers, no DNS Rebinding */
struct config_strlist* private_address;
/** allow domain (and subdomains) to use private address space */
--- unbound-1.4.17.orig/util/configlexer.lex
+++ unbound-1.4.17/util/configlexer.lex
@@ -177,6 +177,7 @@ harden-below-nxdomain{COLON} { YDVAR(1,
harden-referral-path{COLON} { YDVAR(1, VAR_HARDEN_REFERRAL_PATH) }
use-caps-for-id{COLON} { YDVAR(1, VAR_USE_CAPS_FOR_ID) }
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) }
--- unbound-1.4.17.orig/util/configparser.y
+++ unbound-1.4.17/util/configparser.y
@@ -92,6 +92,7 @@ extern struct config_parser_state* cfg_p
%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
@@ -151,6 +152,7 @@ content_server: server_num_threads | ser
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 |
@@ -802,6 +803,15 @@ server_use_caps_for_id: VAR_USE_CAPS_FOR
free($2);
}
;
+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));
--- unbound-1.4.17.orig/pythonmod/interface.i
+++ unbound-1.4.17/pythonmod/interface.i
@@ -626,6 +626,7 @@ 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;