From fa7b7973e36056440dd688c7f312c89600d4f8cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Thu, 14 Nov 2024 10:37:29 +0100
Subject: [PATCH] Limit the additional processing for large RDATA sets
 
When answering queries, don't add data to the additional section if
the answer has more than 13 names in the RDATA.  This limits the
number of lookups into the database(s) during a single client query,
reducing query processing load.
 
Also, don't append any additional data to type=ANY queries. The
answer to ANY is already big enough.
 
(cherry picked from commit a1982cf1bb95c818aa7b58988b5611dec80f2408)
 
Conflict:Context adaptation
Reference:https://downloads.isc.org/isc/bind9/9.18.33/patches/0001-CVE-2024-11187.patch

---
 bind/bind-9.11.36/bin/named/query.c                  |  7 ++++---
 .../bin/tests/system/additional/tests.sh             |  2 +-
 .../bin/tests/system/resolver/ns4/named.noaa         |  5 -----
 bind/bind-9.11.36/bin/tests/system/resolver/tests.sh |  8 ++++++++
 bind/bind-9.11.36/lib/dns/include/dns/rdataset.h     | 10 +++++++++-
 bind/bind-9.11.36/lib/dns/rdataset.c                 |  8 +++++++-
 bind/bind-9.11.36/lib/dns/resolver.c                 | 12 ++++++------
 7 files changed, 35 insertions(+), 17 deletions(-)
 delete mode 100644 bind/bind-9.11.36/bin/tests/system/resolver/ns4/named.noaa

diff --git a/bind/bind-9.11.36/bin/named/query.c b/bind/bind-9.11.36/bin/named/query.c
index f109805..965d104 100644
--- a/bind/bind-9.11.36/bin/named/query.c
+++ b/bind/bind-9.11.36/bin/named/query.c
@@ -1827,7 +1827,7 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
 		 */
 		eresult = dns_rdataset_additionaldata(trdataset,
 						      query_addadditional,
-						      client);
+						      client, DNS_RDATASET_MAXADDITIONAL);
 	}
 
  cleanup:
@@ -2433,7 +2433,7 @@ query_addrdataset(ns_client_t *client, dns_name_t *fname,
 	additionalctx.client = client;
 	additionalctx.rdataset = rdataset;
 	(void)dns_rdataset_additionaldata(rdataset, query_addadditional2,
-					  &additionalctx);
+					  &additionalctx, DNS_RDATASET_MAXADDITIONAL);
 	CTRACE(ISC_LOG_DEBUG(3), "query_addrdataset: done");
 }
 
@@ -2770,7 +2770,8 @@ query_addrrset(ns_client_t *client, dns_name_t **namep,
 	 * To the current response for 'client', add the answer RRset
 	 * '*rdatasetp' and an optional signature set '*sigrdatasetp', with
 	 * owner name '*namep', to section 'section', unless they are
-	 * already there.  Also add any pertinent additional data.
+	 * already there.  Also add any pertinent additional data, unless
+	 * the query was for type ANY.
 	 *
 	 * If 'dbuf' is not NULL, then '*namep' is the name whose data is
 	 * stored in 'dbuf'.  In this case, query_addrrset() guarantees that
diff --git a/bind/bind-9.11.36/bin/tests/system/additional/tests.sh b/bind/bind-9.11.36/bin/tests/system/additional/tests.sh
index 6400723..c82f85d 100644
--- a/bind/bind-9.11.36/bin/tests/system/additional/tests.sh
+++ b/bind/bind-9.11.36/bin/tests/system/additional/tests.sh
@@ -261,7 +261,7 @@ n=`expr $n + 1`
 echo_i "testing with 'minimal-any no;' ($n)"
 ret=0
 $DIG $DIGOPTS -t ANY www.rt.example @10.53.0.1 > dig.out.$n || ret=1
-grep "ANSWER: 3, AUTHORITY: 1, ADDITIONAL: 2" dig.out.$n > /dev/null || ret=1
+grep "ANSWER: 3, AUTHORITY: 2, ADDITIONAL: 1" dig.out.$n >/dev/null || ret=1
 if [ $ret -eq 1 ] ; then
     echo_i "failed"; status=`expr status + 1`
 fi
diff --git a/bind/bind-9.11.36/bin/tests/system/resolver/ns4/named.noaa b/bind/bind-9.11.36/bin/tests/system/resolver/ns4/named.noaa
deleted file mode 100644
index 3b121ad..0000000
--- a/bind/bind-9.11.36/bin/tests/system/resolver/ns4/named.noaa
+++ /dev/null
@@ -1,5 +0,0 @@
-Copyright (C) Internet Systems Consortium, Inc. ("ISC")
-
-See COPYRIGHT in the source root or https://isc.org/copyright.html for terms.
-
-Add -T noaa.
diff --git a/bind/bind-9.11.36/bin/tests/system/resolver/tests.sh b/bind/bind-9.11.36/bin/tests/system/resolver/tests.sh
index 6eb52fe..bf37467 100755
--- a/bind/bind-9.11.36/bin/tests/system/resolver/tests.sh
+++ b/bind/bind-9.11.36/bin/tests/system/resolver/tests.sh
@@ -281,6 +281,10 @@ done
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
+stop_server ns4
+touch ns4/named.noaa
+start_server --noclean --restart --port ${PORT} ns4 || ret=1
+
 n=`expr $n + 1`
 echo_i "RT21594 regression test check setup ($n)"
 ret=0
@@ -317,6 +321,10 @@ grep "status: NXDOMAIN" dig.ns5.out.${n} > /dev/null || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
+stop_server ns4
+rm ns4/named.noaa
+start_server --noclean --restart --port ${PORT} ns4 || ret=1
+
 n=`expr $n + 1`
 echo_i "check that replacement of additional data by a negative cache no data entry clears the additional RRSIGs ($n)"
 ret=0
diff --git a/bind/bind-9.11.36/lib/dns/include/dns/rdataset.h b/bind/bind-9.11.36/lib/dns/include/dns/rdataset.h
index ed9119a..a446673 100644
--- a/bind/bind-9.11.36/lib/dns/include/dns/rdataset.h
+++ b/bind/bind-9.11.36/lib/dns/include/dns/rdataset.h
@@ -53,6 +53,8 @@
 #include <dns/types.h>
 #include <dns/rdatastruct.h>
 
+#define DNS_RDATASET_MAXADDITIONAL 13
+
 ISC_LANG_BEGINDECLS
 
 typedef enum {
@@ -471,7 +473,8 @@ dns_rdataset_towirepartial(dns_rdataset_t *rdataset,
 
 isc_result_t
 dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
-			    dns_additionaldatafunc_t add, void *arg);
+				dns_additionaldatafunc_t add, void *arg,
+			    size_t limit);
 /*%<
  * For each rdata in rdataset, call 'add' for each name and type in the
  * rdata which is subject to additional section processing.
@@ -490,10 +493,15 @@ dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
  *\li	If a call to dns_rdata_additionaldata() is not successful, the
  *	result returned will be the result of dns_rdataset_additionaldata().
  *
+ *\li	If 'limit' is non-zero and the number of the rdatasets is larger
+ *	than 'limit', no additional data will be processed.
+ *
  * Returns:
  *
  *\li	#ISC_R_SUCCESS
  *
+ *\li	#DNS_R_TOOMANYRECORDS in case rdataset count is larger than 'limit'
+ *
  *\li	Any error that dns_rdata_additionaldata() can return.
  */
 
diff --git a/bind/bind-9.11.36/lib/dns/rdataset.c b/bind/bind-9.11.36/lib/dns/rdataset.c
index b42dea5..370ff09 100644
--- a/bind/bind-9.11.36/lib/dns/rdataset.c
+++ b/bind/bind-9.11.36/lib/dns/rdataset.c
@@ -28,6 +28,7 @@
 #include <dns/ncache.h>
 #include <dns/rdata.h>
 #include <dns/rdataset.h>
+#include <dns/result.h>
 
 static const char *trustnames[] = {
 	"none",
@@ -607,7 +608,8 @@ dns_rdataset_towire(dns_rdataset_t *rdataset,
 
 isc_result_t
 dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
-			    dns_additionaldatafunc_t add, void *arg)
+			    dns_additionaldatafunc_t add, void *arg,
+				size_t limit)
 {
 	dns_rdata_t rdata = DNS_RDATA_INIT;
 	isc_result_t result;
@@ -620,6 +622,10 @@ dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
 	REQUIRE(DNS_RDATASET_VALID(rdataset));
 	REQUIRE((rdataset->attributes & DNS_RDATASETATTR_QUESTION) == 0);
 
+	if (limit != 0 && dns_rdataset_count(rdataset) > limit) {
+		return DNS_R_TOOMANYRECORDS;
+	}
+
 	result = dns_rdataset_first(rdataset);
 	if (result != ISC_R_SUCCESS)
 		return (result);
diff --git a/bind/bind-9.11.36/lib/dns/resolver.c b/bind/bind-9.11.36/lib/dns/resolver.c
index 4afd2af..d58cddb 100644
--- a/bind/bind-9.11.36/lib/dns/resolver.c
+++ b/bind/bind-9.11.36/lib/dns/resolver.c
@@ -6462,7 +6462,7 @@ chase_additional(fetchctx_t *fctx, dns_message_t *rmessage) {
 				rdataset->attributes &= ~DNS_RDATASETATTR_CHASE;
 				(void)dns_rdataset_additionaldata(rdataset,
 								  check_related,
-								  &chkarg);
+								  &chkarg, 0);
 				rescan = true;
 			}
 		}
@@ -7097,7 +7097,7 @@ noanswer_response(fetchctx_t *fctx, dns_message_t *message,
 		chkarg.fctx = fctx;
 		chkarg.rmessage = message;
 		(void)dns_rdataset_additionaldata(ns_rdataset, check_related,
-						  &chkarg);
+						  &chkarg, 0);
 #if CHECK_FOR_GLUE_IN_ANSWER
 		/*
 		 * Look in the answer section for "glue" that is incorrectly
@@ -7113,7 +7113,7 @@ noanswer_response(fetchctx_t *fctx, dns_message_t *message,
 			chkarg.fcx = fctx;
 			chkarg.rmessage = message;
 			(void)dns_rdataset_additionaldata(ns_rdataset,
-							  check_answer, &chkarg);
+							  check_answer, &chkarg, 0);
 		}
 #endif
 		FCTX_ATTR_CLR(fctx, FCTX_ATTR_GLUING);
@@ -7355,7 +7355,7 @@ answer_response(fetchctx_t *fctx, dns_message_t *message) {
 			chkarg.rmessage = message;
 			(void)dns_rdataset_additionaldata(rdataset,
 							  check_related,
-							  &chkarg);
+							  &chkarg, 0);
 		}
 	} else if (aname != NULL) {
 		dns_chkarg_t chkarg;
@@ -7383,7 +7383,7 @@ answer_response(fetchctx_t *fctx, dns_message_t *message) {
 		chkarg.fctx = fctx;
 		chkarg.rmessage = message;
 		(void)dns_rdataset_additionaldata(ardataset, check_related,
-						  &chkarg);
+						  &chkarg, 0);
 		for (sigrdataset = ISC_LIST_HEAD(aname->list);
 		     sigrdataset != NULL;
 		     sigrdataset = ISC_LIST_NEXT(sigrdataset, link)) {
@@ -7546,7 +7546,7 @@ answer_response(fetchctx_t *fctx, dns_message_t *message) {
 					(void)dns_rdataset_additionaldata(
 							rdataset,
 							check_related,
-							&chkarg);
+							&chkarg, 0);
 					done = true;
 				}
 			}
-- 
2.43.0

