Merge branch '3405-security-limit-the-number-of-resource-records-in-rrset' into 'v9.20.0-release'

Limit the number of RRs in RRSets

See merge request isc-private/bind9!694

CHANGES

@@ -1,3 +1,19 @@
+6401.	[security]	An excessively large number of rrtypes per owner can
+			slow down database query processing, so a limit has been
+			placed on the number of rrtypes that can be stored per
+			owner (node) in a cache or zone database. This is
+			configured with the new "max-rrtypes-per-name" option,
+			and defaults to 100. (CVE-2024-1737)
+			[GL #3403] [GL #4548]
+
+6400.	[security]	Excessively large rdatasets can slow down database
+			query processing, so a limit has been placed on the
+			number of records that can be stored per rdataset
+			in a cache or zone database. This is configured
+			with the new "max-records-per-type" option, and
+			defaults to 100. (CVE-2024-1737)
+			[GL #497] [GL #3405]
+
 6399.	[security]	Malicious DNS client that sends many queries over
 			TCP but never reads responses can cause server to
 			respond slowly or not respond at all for other

bin/named/config.c

@@ -222,8 +222,10 @@ options {\n\
 	ixfr-from-differences false;\n\
 	max-journal-size default;\n\
 	max-records 0;\n\
+	max-records-per-type 100;\n\
 	max-refresh-time 2419200; /* 4 weeks */\n\
 	max-retry-time 1209600; /* 2 weeks */\n\
+	max-types-per-name 100;\n\
 	max-transfer-idle-in 60;\n\
 	max-transfer-idle-out 60;\n\
 	max-transfer-time-in 120;\n\

bin/named/server.c

@@ -5454,6 +5454,24 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 	dns_resolver_setclientsperquery(view->resolver, cfg_obj_asuint32(obj),
 					max_clients_per_query);
 
+	/*
+	 * This is used for the cache and also as a default value
+	 * for zone databases.
+	 */
+	obj = NULL;
+	result = named_config_get(maps, "max-records-per-type", &obj);
+	INSIST(result == ISC_R_SUCCESS);
+	dns_view_setmaxrrperset(view, cfg_obj_asuint32(obj));
+
+	/*
+	 * This is used for the cache and also as a default value
+	 * for zone databases.
+	 */
+	obj = NULL;
+	result = named_config_get(maps, "max-types-per-name", &obj);
+	INSIST(result == ISC_R_SUCCESS);
+	dns_view_setmaxtypepername(view, cfg_obj_asuint32(obj));
+
 	obj = NULL;
 	result = named_config_get(maps, "max-recursion-depth", &obj);
 	INSIST(result == ISC_R_SUCCESS);

bin/named/zoneconf.c

@@ -1074,6 +1074,22 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		dns_zone_setmaxrecords(zone, 0);
 	}
 
+	obj = NULL;
+	result = named_config_get(maps, "max-records-per-type", &obj);
+	INSIST(result == ISC_R_SUCCESS && obj != NULL);
+	dns_zone_setmaxrrperset(mayberaw, cfg_obj_asuint32(obj));
+	if (zone != mayberaw) {
+		dns_zone_setmaxrrperset(zone, 0);
+	}
+
+	obj = NULL;
+	result = named_config_get(maps, "max-types-per-name", &obj);
+	INSIST(result == ISC_R_SUCCESS && obj != NULL);
+	dns_zone_setmaxtypepername(mayberaw, cfg_obj_asuint32(obj));
+	if (zone != mayberaw) {
+		dns_zone_setmaxtypepername(zone, 0);
+	}
+
 	if (raw != NULL && filename != NULL) {
 #define SIGNED ".signed"
 		size_t signedlen = strlen(filename) + sizeof(SIGNED);

bin/tests/system/doth/ns1/named.conf.in

@@ -98,6 +98,7 @@ options {
 	tcp-initial-timeout 1200;
 	transfers-in 100;
 	transfers-out 100;
+	max-records-per-type 0;
 };
 
 trust-anchors { };

bin/tests/system/doth/ns2/named.conf.in

@@ -52,6 +52,7 @@ options {
 	ixfr-from-differences yes;
 	check-integrity no;
 	dnssec-validation yes;
+	max-records-per-type 0;
 	transfers-in 100;
 	transfers-out 100;
 };

bin/tests/system/doth/ns3/named.conf.in

@@ -44,6 +44,7 @@ options {
 	ixfr-from-differences yes;
 	check-integrity no;
 	dnssec-validation yes;
+	max-records-per-type 0;
 };
 
 trust-anchors { };

bin/tests/system/doth/ns4/named.conf.in

@@ -52,6 +52,7 @@ options {
 	ixfr-from-differences yes;
 	check-integrity no;
 	dnssec-validation yes;
+	max-records-per-type 0;
 };
 
 trust-anchors { };

bin/tests/system/doth/ns5/named.conf.in

@@ -40,6 +40,7 @@ options {
 	ixfr-from-differences yes;
 	check-integrity no;
 	dnssec-validation yes;
+	max-records-per-type 0;
 };
 
 trust-anchors { };

bin/tests/system/limits/ns1/named.conf.in

@@ -23,6 +23,7 @@ options {
 	notify yes;
 	minimal-responses no;
 	dnssec-validation no;
+	max-records-per-type 0;
 };
 
 zone "." {

bin/tests/system/masterformat/ns1/compile.sh

@@ -26,7 +26,12 @@ $CHECKZONE -D -F raw=0 -o example.db.compat example-compat \
   example.db >/dev/null 2>&1
 $CHECKZONE -D -F raw -L 3333 -o example.db.serial.raw example \
   example.db >/dev/null 2>&1
-$CHECKZONE -D -F raw -o large.db.raw large large.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o under-limit.db.raw under-limit under-limit.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o under-limit-kasp.db.raw under-limit-kasp under-limit-kasp.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o on-limit.db.raw on-limit on-limit.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o on-limit-kasp.db.raw on-limit-kasp on-limit-kasp.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o over-limit.db.raw over-limit over-limit.db >/dev/null 2>&1
+$CHECKZONE -D -F raw -o 255types.db.raw 255types 255types.db >/dev/null 2>&1
 
 $KEYGEN -q -a "$DEFAULT_ALGORITHM" -b "$DEFAULT_BITS" -f KSK signed >/dev/null 2>&1
 $KEYGEN -q -a "$DEFAULT_ALGORITHM" -b "$DEFAULT_BITS" signed >/dev/null 2>&1

bin/tests/system/masterformat/ns1/named.conf.in

@@ -23,6 +23,8 @@ options {
 	session-keyfile "session.key";
 	servfail-ttl 0;
 	dnssec-validation no;
+	max-records-per-type 2050;
+	max-types-per-name 500;
 };
 
 key rndc_key {
@@ -78,9 +80,48 @@ zone "transfer4" {
 };
 
 
-zone "large" {
+zone "under-limit" {
 	type primary;
-	file "large.db.raw";
+	file "under-limit.db.raw";
+	masterfile-format raw;
+	allow-transfer { any; };
+};
+
+zone "under-limit-kasp" {
+	type primary;
+	file "under-limit-kasp.db.raw";
+	masterfile-format raw;
+	dnssec-policy masterformat;
+	allow-transfer { any; };
+};
+
+zone "on-limit" {
+	type primary;
+	file "on-limit.db.raw";
+	masterfile-format raw;
+	allow-transfer { any; };
+};
+
+zone "on-limit-kasp" {
+	type primary;
+	file "on-limit-kasp.db.raw";
+	masterfile-format raw;
+	dnssec-policy masterformat;
+	inline-signing no;
+	allow-update { any; };
+	allow-transfer { any; };
+};
+
+zone "over-limit" {
+	type primary;
+	file "over-limit.db.raw";
+	masterfile-format raw;
+	allow-transfer { any; };
+};
+
+zone "255types" {
+	type primary;
+	file "255types.db.raw";
 	masterfile-format raw;
 	allow-transfer { any; };
 };

bin/tests/system/masterformat/ns2/named.conf.in

@@ -22,6 +22,8 @@ options {
 	notify no;
 	servfail-ttl 0;
 	dnssec-validation no;
+	max-records-per-type 2000;
+	max-types-per-name 200;
 };
 
 zone "example" {
@@ -56,9 +58,37 @@ zone "transfer4" {
 	file "transfer.db.full";
 };
 
-zone "large" {
+zone "under-limit" {
 	type secondary;
 	primaries { 10.53.0.1; };
 	masterfile-format raw;
-	file "large.bk";
+	file "under-limit.bk";
+};
+
+zone "under-limit-kasp" {
+	type secondary;
+	primaries { 10.53.0.1; };
+	masterfile-format raw;
+	file "under-limit-kasp.bk";
+};
+
+zone "on-limit" {
+	type secondary;
+	primaries { 10.53.0.1; };
+	masterfile-format raw;
+	file "on-limit.bk";
+};
+
+zone "on-limit-kasp" {
+	type secondary;
+	primaries { 10.53.0.1; };
+	masterfile-format raw;
+	file "on-limit-kasp.bk";
+};
+
+zone "255types" {
+	type secondary;
+	primaries { 10.53.0.1; };
+	masterfile-format raw;
+	file "255types.bk";
 };

bin/tests/system/masterformat/ns4/compile.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0.  If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+# shellcheck source=conf.sh
+. ../../conf.sh
+
+for zone in kasp-max-records-per-type \
+  kasp-max-records-per-type-dnskey \
+  kasp-max-types-per-name; do
+  $CHECKZONE -D -F raw -o $zone.db.raw $zone template.db >/dev/null 2>&1
+done

bin/tests/system/masterformat/ns4/kasp.db

@@ -0,0 +1,28 @@
+; Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+;
+; SPDX-License-Identifier: MPL-2.0
+;
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0.  If a copy of the MPL was not distributed with this
+; file, you can obtain one at https://mozilla.org/MPL/2.0/.
+;
+; See the COPYRIGHT file distributed with this work for additional
+; information regarding copyright ownership.
+
+$TTL 1D
+
+@			IN SOA	ns hostmaster (
+				1
+				3600
+				1800
+				1814400
+				3
+				)
+			NS	ns
+ns			A	10.53.0.1
+mx			MX	10 mail
+a			A	10.53.0.1
+aaaa			AAAA	2001:db8::53
+cname			CNAME	cname-target
+dname			DNAME	dname-target
+txt			TXT	"this is text"

bin/tests/system/masterformat/ns4/named1.conf.in

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+// NS4
+
+options {
+	pid-file "named.pid";
+	listen-on port @PORT@ { 10.53.0.4; };
+	port @PORT@;
+	listen-on-v6 { none; };
+	recursion no;
+	notify no;
+	session-keyfile "session.key";
+	servfail-ttl 0;
+	dnssec-validation no;
+
+	/* Ridicously low on purpose */
+	max-records-per-type 1;
+	max-types-per-name 11;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm @DEFAULT_HMAC@;
+};
+
+controls {
+	inet 10.53.0.4 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+dnssec-policy "masterformat" {
+	keys {
+		ksk key-directory lifetime unlimited algorithm @DEFAULT_ALGORITHM@;
+		zsk key-directory lifetime unlimited algorithm @DEFAULT_ALGORITHM@;
+	};
+};
+
+/*
+ * This one should be okay, since the default policy only introduces one DNSKEY
+ * and each signature covering a different type is considered a separate RRset.
+ */
+zone "kasp-max-records-per-type" {
+	type primary;
+	file "kasp-max-records-per-type.db.raw";
+	masterfile-format raw;
+	dnssec-policy "default";
+	inline-signing no;
+	allow-update { any; };
+	allow-transfer { any; };
+};
+
+/*
+ * This one uses a ZSK / KSK, so that is two records in one RRset,
+ * thus it should fail to sign.
+ */
+zone "kasp-max-records-per-type-dnskey" {
+	type primary;
+	file "kasp-max-records-per-type-dnskey.db.raw";
+	masterfile-format raw;
+	dnssec-policy "masterformat";
+	inline-signing no;
+	allow-update { any; };
+	allow-transfer { any; };
+};
+
+/*
+ * The template zone is fine and should be possible to sign, but when
+ * adding an extra type to the apex the max-types-per-name will be exceeded,
+ * meaning the update should fail.
+ */
+zone "kasp-max-types-per-name" {
+	type primary;
+	file "kasp-max-types-per-name.db.raw";
+	masterfile-format raw;
+	dnssec-policy "default";
+	inline-signing no;
+	allow-update { any; };
+	allow-transfer { any; };
+};

bin/tests/system/masterformat/ns4/named2.conf.in

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+// NS4
+
+options {
+	pid-file "named.pid";
+	listen-on port @PORT@ { 10.53.0.4; };
+	port @PORT@;
+	listen-on-v6 { none; };
+	recursion no;
+	notify no;
+	session-keyfile "session.key";
+	servfail-ttl 0;
+	dnssec-validation no;
+
+	/* Ridicously low on purpose */
+	max-records-per-type 1;
+	max-types-per-name 9;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm @DEFAULT_HMAC@;
+};
+
+controls {
+	inet 10.53.0.4 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+/*
+ * The template zone is fine, but when adding the DNSSEC records to the apex,
+ * the max-types-per-name will be exceeded, meaning signing should fail.
+ */
+zone "kasp-max-types-per-name" {
+	type primary;
+	file "kasp-max-types-per-name.db.raw";
+	masterfile-format raw;
+	dnssec-policy "default";
+	inline-signing no;
+	allow-update { any; };
+	allow-transfer { any; };
+};

bin/tests/system/masterformat/ns4/template.db

@@ -0,0 +1,28 @@
+; Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+;
+; SPDX-License-Identifier: MPL-2.0
+;
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0.  If a copy of the MPL was not distributed with this
+; file, you can obtain one at https://mozilla.org/MPL/2.0/.
+;
+; See the COPYRIGHT file distributed with this work for additional
+; information regarding copyright ownership.
+
+$TTL 1D
+
+@			IN SOA	ns hostmaster (
+				1
+				3600
+				1800
+				1814400
+				3
+				)
+			NS	ns
+ns			A	10.53.0.1
+mx			MX	10 mail
+a			A	10.53.0.1
+aaaa			AAAA	2001:db8::53
+cname			CNAME	cname-target
+dname			DNAME	dname-target
+txt			TXT	"this is text"

bin/tests/system/masterformat/setup.sh

@@ -19,13 +19,44 @@ $SHELL clean.sh
 copy_setports ns1/named.conf.in ns1/named.conf
 copy_setports ns2/named.conf.in ns2/named.conf
 copy_setports ns3/named.conf.in ns3/named.conf
+copy_setports ns4/named1.conf.in ns4/named.conf
 
 cp ns1/example.db ns2/
 cp ns2/formerly-text.db.in ns2/formerly-text.db
-cp ns1/large.db.in ns1/large.db
+cp ns1/empty.db.in ns1/under-limit.db
+
+# counts are set with respect to these limits in named.conf:
+#	max-records-per-type 2050;
+#	max-types-per-name 500;
 awk 'END {
-	 for (i = 0; i < 512; i++ ) { print "a TXT", i; }
-	 for (i = 0; i < 1024; i++ ) { print "b TXT", i; }
-	 for (i = 0; i < 2000; i++ ) { print "c TXT", i; }
-}' </dev/null >>ns1/large.db
-cd ns1 && $SHELL compile.sh
+	 for (i = 0; i < 500; i++ ) { print "500-txt TXT", i; }
+	 for (i = 0; i < 1000; i++ ) { print "1000-txt TXT", i; }
+	 for (i = 0; i < 2000; i++ ) { print "2000-txt TXT", i; }
+}' </dev/null >>ns1/under-limit.db
+cp ns1/under-limit.db ns1/under-limit-kasp.db
+
+cp ns1/empty.db.in ns1/on-limit.db
+awk 'END {
+	 for (i = 0; i < 500; i++ ) { print "500-txt TXT", i; }
+	 for (i = 0; i < 1000; i++ ) { print "1000-txt TXT", i; }
+	 for (i = 0; i < 2000; i++ ) { print "2000-txt TXT", i; }
+	 for (i = 0; i < 2050; i++ ) { print "2050-txt TXT", i; }
+}' </dev/null >>ns1/on-limit.db
+cp ns1/on-limit.db ns1/on-limit-kasp.db
+
+cp ns1/empty.db.in ns1/over-limit.db
+awk 'END {
+	 for (i = 0; i < 500; i++ ) { print "500-txt TXT", i; }
+	 for (i = 0; i < 1000; i++ ) { print "1000-txt TXT", i; }
+	 for (i = 0; i < 2000; i++ ) { print "2000-txt TXT", i; }
+	 for (i = 0; i < 2050; i++ ) { print "2050-txt TXT", i; }
+	 for (i = 0; i < 2100; i++ ) { print "2100-txt TXT", i; }
+}' </dev/null >>ns1/over-limit.db
+
+cp ns1/empty.db.in ns1/255types.db
+for ntype in $(seq 65280 65534); do
+  echo "m TYPE${ntype} \# 0"
+done >>ns1/255types.db
+echo "m TXT bunny" >>ns1/255types.db
+(cd ns1 && $SHELL compile.sh)
+(cd ns4 && $SHELL compile.sh)

bin/tests/system/masterformat/tests.sh

@@ -134,7 +134,7 @@ n=$((n + 1))
 status=$((status + ret))
 
 echo_i "waiting for transfers to complete"
-for i in 0 1 2 3 4 5 6 7 8 9; do
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
   test -f ns2/transfer.db.raw -a -f ns2/transfer.db.txt && break
   sleep 1
 done
@@ -162,7 +162,7 @@ n=$((n + 1))
 status=$((status + ret))
 
 echo_i "checking that secondary formerly in text format is now raw ($n)"
-for i in 0 1 2 3 4 5 6 7 8 9; do
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
   ret=0
   israw ns2/formerly-text.db >/dev/null 2>&1 || ret=1
   [ "$(rawversion ns2/formerly-text.db)" -eq 1 ] || ret=1
@@ -173,12 +173,12 @@ n=$((n + 1))
 [ $ret -eq 0 ] || echo_i "failed"
 status=$((status + ret))
 
-echo_i "checking that large rdatasets loaded ($n)"
-for i in 0 1 2 3 4 5 6 7 8 9; do
+echo_i "checking that under-limit rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
   ret=0
-  for a in a b c; do
-    $DIG +tcp txt "${a}.large" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.test$n"
-    grep "status: NOERROR" "dig.out.ns2.test$n" >/dev/null || ret=1
+  for rrcount in 500-txt 1000-txt 2000-txt; do
+    $DIG +tcp txt "${rrcount}.under-limit" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
   done
   [ $ret -eq 0 ] && break
   sleep 1
@@ -187,6 +187,253 @@ n=$((n + 1))
 [ $ret -eq 0 ] || echo_i "failed"
 status=$((status + ret))
 
+echo_i "checking that under-limit rdatasets transfered ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt; do
+    $DIG +tcp txt "${rrcount}.under-limit" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns2.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that under-limit-kasp dnskeys loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+
+  $DIG +tcp +dnssec dnskey "under-limit-kasp" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.dnskey.test$n"
+  grep "status: NOERROR" "dig.out.ns1.dnskey.test$n" >/dev/null || ret=1
+  grep "RRSIG" "dig.out.ns1.dnskey.test$n" >/dev/null || ret=1
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that under-limit-kasp rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt; do
+    $DIG +tcp +dnssec txt "${rrcount}.under-limit-kasp" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that under-limit-kasp rdatasets transfered ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt; do
+    $DIG +tcp +dnssec txt "${rrcount}.under-limit-kasp" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns2.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that on-limit rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt; do
+    $DIG +tcp txt "${rrcount}.on-limit" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that on-limit rdatasets not transfered ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt; do
+    $DIG +tcp txt "${rrcount}.on-limit" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.$rrcount.test$n"
+    grep "status: SERVFAIL" "dig.out.ns2.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that on-limit-kasp rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt; do
+    $DIG +tcp +dnssec txt "${rrcount}.on-limit-kasp" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that on-limit-kasp rdatasets not transfered ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt; do
+    $DIG +tcp +dnssec txt "${rrcount}.on-limit-kasp" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.$rrcount.test$n"
+    grep "status: SERVFAIL" "dig.out.ns2.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that over-limit rdatasets not loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt 2100-txt; do
+    $DIG +tcp txt "${rrcount}.over-limit" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: SERVFAIL" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that kasp-max-records-per-type rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrtype in soa dnskey ns; do
+    $DIG +tcp +dnssec $rrtype "kasp-max-records-per-type" @10.53.0.4 -p "${PORT}" >"dig.out.ns4.$rrtype.test$n"
+    grep "status: NOERROR" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that kasp-max-records-per-type-dnskey rdatasets not signed ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrtype in soa dnskey ns; do
+    $DIG +tcp +dnssec $rrtype "kasp-max-records-per-type-dnskey" @10.53.0.4 -p "${PORT}" >"dig.out.ns4.$rrtype.test$n"
+    grep "status: NOERROR" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns4.$rrtype.test$n" >/dev/null && ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that kasp-max-types-per-name rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrtype in soa dnskey ns; do
+    $DIG +tcp +dnssec $rrtype "kasp-max-types-per-name" @10.53.0.4 -p "${PORT}" >"dig.out.ns4.$rrtype.test$n"
+    grep "status: NOERROR" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+# Update zone with nsupdate.
+n=$((n + 1))
+echo_i "add new type to zone and check that it fails ($n)"
+ret=0
+(
+  echo zone kasp-max-types-per-name.
+  echo server 10.53.0.4 "$PORT"
+  echo update add kasp-max-types-per-name. 300 TXT KAPUTT
+  echo send
+) | $NSUPDATE && ret=1
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that kasp-max-types-per-name rdatasets loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrtype in soa dnskey ns txt; do
+    $DIG +tcp +dnssec $rrtype "kasp-max-types-per-name" @10.53.0.4 -p "${PORT}" >"dig.out.ns4.$rrtype.test$n"
+    grep "status: NOERROR" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+    grep "KAPUTT" "dig.out.ns4.$rrtype.test$n" >/dev/null && ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+# Reconfigure ns4
+echo_i "reconfigure ns4"
+stop_server ns4
+copy_setports ns4/named2.conf.in ns4/named.conf
+# Recompile zone
+$CHECKZONE -D -F raw -o ns4/kasp.db.raw kasp-max-types-per-name ns4/template.db >/dev/null 2>&1
+start_server --noclean --restart --port "${PORT}" ns4
+
+echo_i "checking that kasp-max-types-per-name rdatasets not loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrtype in soa dnskey ns; do
+    $DIG +tcp +dnssec $rrtype "kasp-max-types-per-name" @10.53.0.4 -p "${PORT}" >"dig.out.ns4.$rrtype.test$n"
+    grep "status: SERVFAIL" "dig.out.ns4.$rrtype.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that 255 types are loaded ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  $DIG +tcp TXT "m.255types" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.test$n"
+  grep "status: NOERROR" "dig.out.ns1.test$n" >/dev/null || ret=1
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
+echo_i "checking that 255 types types are not transfered ($n)"
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  $DIG +tcp TXT "m.255types" @10.53.0.2 -p "${PORT}" >"dig.out.ns2.test$n"
+  grep "status: SERVFAIL" "dig.out.ns2.test$n" >/dev/null || ret=1
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
 echo_i "checking format transitions: text->raw->text ($n)"
 ret=0
 $CHECKZONE -D -f text -F text -o baseline.txt example.nil ns1/example.db >/dev/null
@@ -240,7 +487,7 @@ stop_server --use-rndc --port ${CONTROLPORT} ns3
 rm ns3/*.jnl
 restart
 #shellcheck disable=SC2034
-for i in 0 1 2 3 4 5 6 7 8 9; do
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
   lret=0
   dig_with_opts +comm @10.53.0.3 moretext.dynamic txt >"dig.out.dynamic2.ns3.test$n"
   grep "more text" "dig.out.dynamic2.ns3.test$n" >/dev/null 2>&1 || lret=1
@@ -273,5 +520,24 @@ n=$((n + 1))
 [ $ret -eq 0 ] || echo_i "failed"
 status=$((status + ret))
 
+echo_i "checking that on-limit-kasp rdatasets loaded after re-sign and re-start ($n)"
+ret=0
+stop_server ns1
+start_server --noclean --restart --port "${PORT}" ns1
+
+for _attempt in 0 1 2 3 4 5 6 7 8 9; do
+  ret=0
+  for rrcount in 500-txt 1000-txt 2000-txt 2050-txt; do
+    $DIG +tcp +dnssec txt "${rrcount}.on-limit-kasp" @10.53.0.1 -p "${PORT}" >"dig.out.ns1.$rrcount.test$n"
+    grep "status: NOERROR" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+    grep "RRSIG" "dig.out.ns1.$rrcount.test$n" >/dev/null || ret=1
+  done
+  [ $ret -eq 0 ] && break
+  sleep 1
+done
+n=$((n + 1))
+[ $ret -eq 0 ] || echo_i "failed"
+status=$((status + ret))
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1

bin/tests/system/reclimit/ns1/named.conf.in

@@ -22,6 +22,13 @@ options {
 	listen-on-v6 { none; };
 	recursion no;
 	dnssec-validation no;
+	max-records-per-type 0;
+	max-types-per-name 0;
 };
 
 zone "." { type primary; file "root.db"; };
+
+zone "big." {
+	type primary;
+	file "big.db";
+};

bin/tests/system/reclimit/ns1/root.db

@@ -19,3 +19,6 @@ example.net. 60 IN NS direct.example.net.
 direct.example.net. 60 IN A 10.53.0.2
 example.com. 60 IN NS direct.example.com.
 direct.example.com. 60 IN A 10.53.0.4
+
+big. in NS ns.big.
+ns.big. 60 IN A 10.53.0.1

bin/tests/system/reclimit/ns3/named5.conf.in

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	directory ".";
+	query-source address 10.53.0.3;
+	notify-source 10.53.0.3;
+	transfer-source 10.53.0.3;
+	port @PORT@;
+	pid-file "named.pid";
+	listen-on { 10.53.0.3; };
+	listen-on-v6 { none; };
+	servfail-ttl 0;
+	qname-minimization disabled;
+	max-recursion-depth 12;
+	recursion yes;
+	dnssec-validation yes;
+	max-records-per-type 0;
+	max-types-per-name 10;
+};
+
+trust-anchors { };
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm @DEFAULT_HMAC@;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };

bin/tests/system/reclimit/ns3/named6.conf.in

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0.  If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+options {
+	directory ".";
+	query-source address 10.53.0.3;
+	notify-source 10.53.0.3;
+	transfer-source 10.53.0.3;
+	port @PORT@;
+	pid-file "named.pid";
+	listen-on { 10.53.0.3; };
+	listen-on-v6 { none; };
+	servfail-ttl 0;
+	qname-minimization disabled;
+	max-recursion-depth 12;
+	recursion yes;
+	dnssec-validation yes;
+	max-records-per-type 0;
+	max-types-per-name 0;
+};
+
+trust-anchors { };
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm @DEFAULT_HMAC@;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };

bin/tests/system/reclimit/tests.sh

@@ -222,6 +222,50 @@ eval count=$(cat dig.out.3.test$n)
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=$((status + ret))
 
-#grep "duplicate query" ns3/named.run
+n=$((n + 1))
+echo_i "checking RRset that exceeds max-records-per-type ($n)"
+ret=0
+$DIG $DIGOPTS @10.53.0.3 biganswer.big >dig.out.1.test$n || ret=1
+grep 'status: SERVFAIL' dig.out.1.test$n >/dev/null || ret=1
+ns3_reset ns3/named5.conf.in
+$DIG $DIGOPTS @10.53.0.3 biganswer.big >dig.out.2.test$n || ret=1
+grep 'status: NOERROR' dig.out.2.test$n >/dev/null || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=$((status + ret))
+
+check_manytypes() (
+  i=$1
+  type=$2
+  expected=$3
+
+  $DIG $DIGOPTS @10.53.0.3 IN $type manytypes.big >dig.out.$i.$type.test$n || exit 1
+  grep 'status: '"${expected}"'' dig.out.$i.$type.test$n >/dev/null || exit 1
+
+  exit 0
+)
+
+n=$((n + 1))
+echo_i "checking name that exceeds max-types-per-name ($n)"
+ret=0
+
+# Limited to 10 types - these should be fine
+for ntype in $(seq 65280 65289); do
+  check_manytypes 1 "TYPE${ntype}" NOERROR || ret=1
+done
+# Everything on top of that should SERVFAIL
+for ntype in $(seq 65290 65534); do
+  check_manytypes 1 "TYPE${ntype}" SERVFAIL || ret=1
+done
+
+# Lift the limit
+ns3_reset ns3/named6.conf.in
+
+for ntype in $(seq 65280 65534); do
+  check_manytypes 2 "TYPE${ntype}" NOERROR || ret=1
+done
+
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=$((status + ret))
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1

doc/arm/reference.rst

@@ -3681,6 +3681,36 @@ system.
    This sets the maximum number of records permitted in a zone. The default is
    zero, which means the maximum is unlimited.
 
+.. namedconf:statement:: max-records-per-type
+   :tags: server
+   :short: Sets the maximum number of records that can be stored in an RRset
+
+   This sets the maximum number of resource records that can be stored
+   in an RRset in a database. When configured in :namedconf:ref:`options`
+   or :namedconf:ref:`view`, it controls the cache database; it also sets
+   the default value for zone databases, which can be overridden by setting
+   it at the :namedconf:ref:`zone` level.
+
+   If set to a positive value, any attempt to cache or to add to a zone
+   an RRset with more than the specified number of records will result in
+   a failure.  If set to 0, there is no cap on RRset size.  The default is
+   100.
+
+.. namedconf:statement:: max-types-per-name
+   :tags: server
+   :short: Sets the maximum number of RR types that can be stored for an owner name
+
+   This sets the maximum number of resource record types that can be stored
+   for a single owner name in a database. When configured in :namedconf:ref:`options`
+   or :namedconf:ref:`view`, it controls the cache database, and also sets
+   the default value for zone databases, which can be overridden by setting
+   it at the :namedconf:ref:`zone` level
+
+   If set to a positive value, any attempt to cache or to add to a zone an owner
+   name with more than the specified number of resource record types will result
+   in a failure.  If set to 0, there is no cap on RR types number.  The default is
+   100.
+
 .. namedconf:statement:: recursive-clients
    :tags: query
    :short: Specifies the maximum number of concurrent recursive queries the server can perform.

doc/misc/mirror.zoneopt

@@ -16,12 +16,14 @@ zone <string> [ <class> ] {
 	max-ixfr-ratio ( unlimited | <percentage> );
 	max-journal-size ( default | unlimited | <sizeval> );
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-refresh-time <integer>;
 	max-retry-time <integer>;
 	max-transfer-idle-in <integer>;
 	max-transfer-idle-out <integer>;
 	max-transfer-time-in <integer>;
 	max-transfer-time-out <integer>;
+	max-types-per-name <integer>;
 	min-refresh-time <integer>;
 	min-retry-time <integer>;
 	multi-master <boolean>;

doc/misc/options

@@ -183,6 +183,7 @@ options {
 	max-journal-size ( default | unlimited | <sizeval> );
 	max-ncache-ttl <duration>;
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-recursion-depth <integer>;
 	max-recursion-queries <integer>;
 	max-refresh-time <integer>;
@@ -193,6 +194,7 @@ options {
 	max-transfer-idle-out <integer>;
 	max-transfer-time-in <integer>;
 	max-transfer-time-out <integer>;
+	max-types-per-name <integer>;
 	max-udp-size <integer>;
 	max-validation-failures-per-fetch <integer>; // experimental
 	max-validations-per-fetch <integer>; // experimental
@@ -468,6 +470,7 @@ view <string> [ <class> ] {
 	max-journal-size ( default | unlimited | <sizeval> );
 	max-ncache-ttl <duration>;
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-recursion-depth <integer>;
 	max-recursion-queries <integer>;
 	max-refresh-time <integer>;
@@ -477,6 +480,7 @@ view <string> [ <class> ] {
 	max-transfer-idle-out <integer>;
 	max-transfer-time-in <integer>;
 	max-transfer-time-out <integer>;
+	max-types-per-name <integer>;
 	max-udp-size <integer>;
 	max-validation-failures-per-fetch <integer>; // experimental
 	max-validations-per-fetch <integer>; // experimental

doc/misc/primary.zoneopt

@@ -37,8 +37,10 @@ zone <string> [ <class> ] {
 	max-ixfr-ratio ( unlimited | <percentage> );
 	max-journal-size ( default | unlimited | <sizeval> );
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-transfer-idle-out <integer>;
 	max-transfer-time-out <integer>;
+	max-types-per-name <integer>;
 	max-zone-ttl ( unlimited | <duration> ); // deprecated
 	notify ( explicit | master-only | primary-only | <boolean> );
 	notify-delay <integer>;

doc/misc/redirect.zoneopt

@@ -7,6 +7,8 @@ zone <string> [ <class> ] {
 	masterfile-format ( raw | text );
 	masterfile-style ( full | relative );
 	max-records <integer>;
+	max-records-per-type <integer>;
+	max-types-per-name <integer>;
 	max-zone-ttl ( unlimited | <duration> ); // deprecated
 	primaries [ port <integer> ] [ source ( <ipv4_address> | * ) ] [ source-v6 ( <ipv6_address> | * ) ] { ( <remote-servers> | <ipv4_address> [ port <integer> ] | <ipv6_address> [ port <integer> ] ) [ key <string> ] [ tls <string> ]; ... };
 	zone-statistics ( full | terse | none | <boolean> );

doc/misc/secondary.zoneopt

@@ -28,12 +28,14 @@ zone <string> [ <class> ] {
 	max-ixfr-ratio ( unlimited | <percentage> );
 	max-journal-size ( default | unlimited | <sizeval> );
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-refresh-time <integer>;
 	max-retry-time <integer>;
 	max-transfer-idle-in <integer>;
 	max-transfer-idle-out <integer>;
 	max-transfer-time-in <integer>;
 	max-transfer-time-out <integer>;
+	max-types-per-name <integer>;
 	min-refresh-time <integer>;
 	min-retry-time <integer>;
 	multi-master <boolean>;

doc/misc/static-stub.zoneopt

@@ -5,6 +5,8 @@ zone <string> [ <class> ] {
 	forward ( first | only );
 	forwarders [ port <integer> ] [ tls <string> ] { ( <ipv4_address> | <ipv6_address> ) [ port <integer> ] [ tls <string> ]; ... };
 	max-records <integer>;
+	max-records-per-type <integer>;
+	max-types-per-name <integer>;
 	server-addresses { ( <ipv4_address> | <ipv6_address> ); ... };
 	server-names { <string>; ... };
 	zone-statistics ( full | terse | none | <boolean> );

doc/misc/stub.zoneopt

@@ -11,10 +11,12 @@ zone <string> [ <class> ] {
 	masterfile-format ( raw | text );
 	masterfile-style ( full | relative );
 	max-records <integer>;
+	max-records-per-type <integer>;
 	max-refresh-time <integer>;
 	max-retry-time <integer>;
 	max-transfer-idle-in <integer>;
 	max-transfer-time-in <integer>;
+	max-types-per-name <integer>;
 	min-refresh-time <integer>;
 	min-retry-time <integer>;
 	multi-master <boolean>;

doc/notes/notes-current.rst

@@ -19,6 +19,21 @@ Security Fixes
   responses can cause server to respond slowly or not respond at all for other
   clients. :cve:`2024-0760` :gl:`#4481`
 
+- Excessively large resource record sets can be crafted to slow down
+  database processing. This has been addressed by adding a configurable
+  limit to the number of records that can be stored per name and type in
+  a cache or zone database. The default is 100, but it can be tuned with
+  the new ``max-records-per-type`` option. :gl:`#497` :gl:`#3405`
+
+  An excessively large number of resource record types for a single owner name can
+  be crafted to slow down database processing. This has been addressed by adding
+  a configurable limit to the number of records that can be stored per name and
+  type in a cache or zone database.  The default is 100, and can be tuned with
+  the new ``max-rrtypes-per-name`` option. :cve:`2024-1737` :gl:`#3403`
+
+  ISC would like to thank Toshifumi Sakaguchi who independently discovered
+  and responsibly reported the issue to ISC. :gl:`#4548`
+
 New Features
 ~~~~~~~~~~~~
 

lib/dns/cache.c

@@ -80,6 +80,8 @@ struct dns_cache {
 	dns_ttl_t serve_stale_ttl;
 	dns_ttl_t serve_stale_refresh;
 	isc_stats_t *stats;
+	uint32_t maxrrperset;
+	uint32_t maxtypepername;
 };
 
 /***
@@ -128,6 +130,8 @@ cache_create_db(dns_cache_t *cache, dns_db_t **dbp, isc_mem_t **tmctxp,
 
 	dns_db_setservestalettl(db, cache->serve_stale_ttl);
 	dns_db_setservestalerefresh(db, cache->serve_stale_refresh);
+	dns_db_setmaxrrperset(db, cache->maxrrperset);
+	dns_db_setmaxtypepername(db, cache->maxtypepername);
 
 	/*
 	 * XXX this is only used by the RBT cache, and can
@@ -546,6 +550,26 @@ dns_cache_updatestats(dns_cache_t *cache, isc_result_t result) {
 	}
 }
 
+void
+dns_cache_setmaxrrperset(dns_cache_t *cache, uint32_t value) {
+	REQUIRE(VALID_CACHE(cache));
+
+	cache->maxrrperset = value;
+	if (cache->db != NULL) {
+		dns_db_setmaxrrperset(cache->db, value);
+	}
+}
+
+void
+dns_cache_setmaxtypepername(dns_cache_t *cache, uint32_t value) {
+	REQUIRE(VALID_CACHE(cache));
+
+	cache->maxtypepername = value;
+	if (cache->db != NULL) {
+		dns_db_setmaxtypepername(cache->db, value);
+	}
+}
+
 /*
  * XXX: Much of the following code has been copied in from statschannel.c.
  * We should refactor this into a generic function in stats.c that can be

lib/dns/db.c

@@ -1170,3 +1170,21 @@ dns_db_nodefullname(dns_db_t *db, dns_dbnode_t *node, dns_name_t *name) {
 	}
 	return (ISC_R_NOTIMPLEMENTED);
 }
+
+void
+dns_db_setmaxrrperset(dns_db_t *db, uint32_t value) {
+	REQUIRE(DNS_DB_VALID(db));
+
+	if (db->methods->setmaxrrperset != NULL) {
+		(db->methods->setmaxrrperset)(db, value);
+	}
+}
+
+void
+dns_db_setmaxtypepername(dns_db_t *db, uint32_t value) {
+	REQUIRE(DNS_DB_VALID(db));
+
+	if (db->methods->setmaxtypepername != NULL) {
+		(db->methods->setmaxtypepername)(db, value);
+	}
+}

lib/dns/include/dns/cache.h

@@ -246,6 +246,18 @@ dns_cache_updatestats(dns_cache_t *cache, isc_result_t result);
  * Update cache statistics based on result code in 'result'
  */
 
+void
+dns_cache_setmaxrrperset(dns_cache_t *cache, uint32_t value);
+/*%<
+ * Set the maximum resource records per RRSet that can be cached.
+ */
+
+void
+dns_cache_setmaxtypepername(dns_cache_t *cache, uint32_t value);
+/*%<
+ * Set the maximum resource record types per owner name that can be cached.
+ */
+
 #ifdef HAVE_LIBXML2
 int
 dns_cache_renderxml(dns_cache_t *cache, void *writer0);

lib/dns/include/dns/db.h

@@ -183,6 +183,8 @@ typedef struct dns_dbmethods {
 	void (*deletedata)(dns_db_t *db, dns_dbnode_t *node, void *data);
 	isc_result_t (*nodefullname)(dns_db_t *db, dns_dbnode_t *node,
 				     dns_name_t *name);
+	void (*setmaxrrperset)(dns_db_t *db, uint32_t value);
+	void (*setmaxtypepername)(dns_db_t *db, uint32_t value);
 } dns_dbmethods_t;
 
 typedef isc_result_t (*dns_dbcreatefunc_t)(isc_mem_t	    *mctx,
@@ -1800,4 +1802,23 @@ dns_db_nodefullname(dns_db_t *db, dns_dbnode_t *node, dns_name_t *name);
  * \li 'db' is a valid database
  * \li 'node' and 'name' are not NULL
  */
+
+void
+dns_db_setmaxrrperset(dns_db_t *db, uint32_t value);
+/*%<
+ * Set the maximum permissible number of RRs per RRset.
+ *
+ * If 'value' is nonzero, then any subsequent attempt to add an rdataset
+ * with more than 'value' RRs will return ISC_R_TOOMANYRECORDS.
+ */
+
+void
+dns_db_setmaxtypepername(dns_db_t *db, uint32_t value);
+/*%<
+ * Set the maximum permissible number of RR types per owner name.
+ *
+ * If 'value' is nonzero, and if there are already 'value' RR types
+ * stored at a given node, then any subsequent attempt to add an rdataset
+ * with a new RR type will return ISC_R_TOOMANYRECORDS.
+ */
 ISC_LANG_ENDDECLS

lib/dns/include/dns/rdataslab.h

@@ -169,7 +169,8 @@ extern dns_rdatasetmethods_t dns_rdataslab_rdatasetmethods;
 
 isc_result_t
 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
-			   isc_region_t *region, unsigned int reservelen);
+			   isc_region_t *region, unsigned int reservelen,
+			   uint32_t limit);
 /*%<
  * Slabify a rdataset.  The slab area will be allocated and returned
  * in 'region'.
@@ -225,7 +226,8 @@ isc_result_t
 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
 		    unsigned int reservelen, isc_mem_t *mctx,
 		    dns_rdataclass_t rdclass, dns_rdatatype_t type,
-		    unsigned int flags, unsigned char **tslabp);
+		    unsigned int flags, uint32_t maxrrperset,
+		    unsigned char **tslabp);
 /*%<
  * Merge 'oslab' and 'nslab'.
  */

lib/dns/include/dns/view.h

@@ -183,6 +183,8 @@ struct dns_view {
 	uint32_t	      fail_ttl;
 	dns_badcache_t	     *failcache;
 	unsigned int	      udpsize;
+	uint32_t	      maxrrperset;
+	uint32_t	      maxtypepername;
 
 	/*
 	 * Configurable data for server use only,
@@ -1242,6 +1244,18 @@ dns_view_getresolver(dns_view_t *view, dns_resolver_t **resolverp);
  * Return the resolver associated with the view.
  */
 
+void
+dns_view_setmaxrrperset(dns_view_t *view, uint32_t value);
+/*%<
+ * Set the maximum resource records per RRSet that can be cached.
+ */
+
+void
+dns_view_setmaxtypepername(dns_view_t *view, uint32_t value);
+/*%<
+ * Set the maximum resource record types per owner name that can be cached.
+ */
+
 void
 dns_view_setudpsize(dns_view_t *view, uint16_t udpsize);
 /*%<

lib/dns/include/dns/zone.h

@@ -366,6 +366,32 @@ dns_zone_getmaxrecords(dns_zone_t *zone);
  *\li	uint32_t maxrecords.
  */
 
+void
+dns_zone_setmaxrrperset(dns_zone_t *zone, uint32_t maxrrperset);
+/*%<
+ * 	Sets the maximum number of records per rrset permitted in a zone.
+ *	0 implies unlimited.
+ *
+ * Requires:
+ *\li	'zone' to be valid initialised zone.
+ *
+ * Returns:
+ *\li	void
+ */
+
+void
+dns_zone_setmaxtypepername(dns_zone_t *zone, uint32_t maxtypepername);
+/*%<
+ * 	Sets the maximum number of resource record types per owner name
+ *	permitted in a zone.  0 implies unlimited.
+ *
+ * Requires:
+ *\li	'zone' to be valid initialised zone.
+ *
+ * Returns:
+ *\li	void
+ */
+
 void
 dns_zone_setmaxttl(dns_zone_t *zone, uint32_t maxttl);
 /*%<

lib/dns/qpcache.c

@@ -217,6 +217,9 @@ struct qpcache {
 	/* Locked by lock. */
 	unsigned int active;
 
+	uint32_t maxrrperset;	 /* Maximum RRs per RRset */
+	uint32_t maxtypepername; /* Maximum number of RR types per owner */
+
 	/*
 	 * The time after a failed lookup, where stale answers from cache
 	 * may be used directly in a DNS response without attempting a
@@ -2883,6 +2886,7 @@ add(qpcache_t *qpdb, qpcnode_t *qpnode,
 	dns_typepair_t negtype = 0, sigtype;
 	dns_trust_t trust;
 	int idx;
+	uint32_t ntypes;
 
 	if ((options & DNS_DBADD_FORCE) != 0) {
 		trust = dns_trust_ultimate;
@@ -2915,6 +2919,7 @@ add(qpcache_t *qpdb, qpcnode_t *qpnode,
 				{
 					mark_ancient(topheader);
 				}
+				ntypes = 0; /* Always add the negative entry */
 				goto find_header;
 			}
 			/*
@@ -2938,9 +2943,11 @@ add(qpcache_t *qpdb, qpcnode_t *qpnode,
 			 * check for an extant non-ancient NODATA ncache
 			 * entry which covers the same type as the RRSIG.
 			 */
+			ntypes = 0;
 			for (topheader = qpnode->data; topheader != NULL;
 			     topheader = topheader->next)
 			{
+				++ntypes;
 				if ((topheader->type == RDATATYPE_NCACHEANY) ||
 				    (newheader->type == sigtype &&
 				     topheader->type ==
@@ -2983,9 +2990,12 @@ add(qpcache_t *qpdb, qpcnode_t *qpnode,
 		}
 	}
 
+	ntypes = 0;
 	for (topheader = qpnode->data; topheader != NULL;
 	     topheader = topheader->next)
 	{
+		++ntypes;
+
 		if (prio_type(topheader->type)) {
 			prioheader = topheader;
 		}
@@ -3253,6 +3263,14 @@ find_header:
 			/*
 			 * No rdatasets of the given type exist at the node.
 			 */
+			if (trust != dns_trust_ultimate &&
+			    qpdb->maxtypepername > 0 &&
+			    ntypes >= qpdb->maxtypepername)
+			{
+				dns_slabheader_destroy(&newheader);
+				return (DNS_R_TOOMANYRECORDS);
+			}
+
 			INSIST(newheader->down == NULL);
 
 			if (prio_type(newheader->type)) {
@@ -3280,7 +3298,7 @@ find_header:
 }
 
 static isc_result_t
-addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader,
+addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
 	   dns_rdataset_t *rdataset) {
 	isc_result_t result;
 	dns_slabheader_proof_t *noqname = NULL;
@@ -3291,12 +3309,12 @@ addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader,
 	result = dns_rdataset_getnoqname(rdataset, &name, &neg, &negsig);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
-	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0);
+	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
 
-	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0);
+	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
@@ -3319,7 +3337,7 @@ cleanup:
 }
 
 static isc_result_t
-addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader,
+addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
 	   dns_rdataset_t *rdataset) {
 	isc_result_t result;
 	dns_slabheader_proof_t *closest = NULL;
@@ -3330,12 +3348,12 @@ addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader,
 	result = dns_rdataset_getclosest(rdataset, &name, &neg, &negsig);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
-	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0);
+	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
 
-	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0);
+	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
@@ -3386,7 +3404,8 @@ addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
 	}
 
 	result = dns_rdataslab_fromrdataset(rdataset, qpdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    qpdb->maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -3423,14 +3442,16 @@ addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
 		DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_OPTOUT);
 	}
 	if ((rdataset->attributes & DNS_RDATASETATTR_NOQNAME) != 0) {
-		result = addnoqname(qpdb->common.mctx, newheader, rdataset);
+		result = addnoqname(qpdb->common.mctx, newheader,
+				    qpdb->maxrrperset, rdataset);
 		if (result != ISC_R_SUCCESS) {
 			dns_slabheader_destroy(&newheader);
 			return (result);
 		}
 	}
 	if ((rdataset->attributes & DNS_RDATASETATTR_CLOSEST) != 0) {
-		result = addclosest(qpdb->common.mctx, newheader, rdataset);
+		result = addclosest(qpdb->common.mctx, newheader,
+				    qpdb->maxrrperset, rdataset);
 		if (result != ISC_R_SUCCESS) {
 			dns_slabheader_destroy(&newheader);
 			return (result);
@@ -4330,6 +4351,24 @@ expire_ttl_headers(qpcache_t *qpdb, unsigned int locknum,
 	}
 }
 
+static void
+setmaxrrperset(dns_db_t *db, uint32_t value) {
+	qpcache_t *qpdb = (qpcache_t *)db;
+
+	REQUIRE(VALID_QPDB(qpdb));
+
+	qpdb->maxrrperset = value;
+}
+
+static void
+setmaxtypepername(dns_db_t *db, uint32_t value) {
+	qpcache_t *qpdb = (qpcache_t *)db;
+
+	REQUIRE(VALID_QPDB(qpdb));
+
+	qpdb->maxtypepername = value;
+}
+
 static dns_dbmethods_t qpdb_cachemethods = {
 	.destroy = qpdb_destroy,
 	.findnode = findnode,
@@ -4354,6 +4393,8 @@ static dns_dbmethods_t qpdb_cachemethods = {
 	.unlocknode = unlocknode,
 	.expiredata = expiredata,
 	.deletedata = deletedata,
+	.setmaxrrperset = setmaxrrperset,
+	.setmaxtypepername = setmaxtypepername,
 };
 
 static void

lib/dns/qpzone.c

@@ -178,6 +178,8 @@ struct qpzonedb {
 	uint32_t current_serial;
 	uint32_t least_serial;
 	uint32_t next_serial;
+	uint32_t maxrrperset;	 /* Maximum RRs per RRset */
+	uint32_t maxtypepername; /* Maximum number of RR types per owner */
 	qpz_version_t *current_version;
 	qpz_version_t *future_version;
 	qpz_versionlist_t open_versions;
@@ -1833,6 +1835,7 @@ add(qpzonedb_t *qpdb, qpznode_t *node, const dns_name_t *nodename,
 	unsigned char *merged = NULL;
 	isc_result_t result;
 	bool merge = false;
+	uint32_t ntypes;
 
 	if ((options & DNS_DBADD_MERGE) != 0) {
 		REQUIRE(version != NULL);
@@ -1848,9 +1851,11 @@ add(qpzonedb_t *qpdb, qpznode_t *node, const dns_name_t *nodename,
 		changed = add_changed(newheader, version DNS__DB_FLARG_PASS);
 	}
 
+	ntypes = 0;
 	for (topheader = node->data; topheader != NULL;
 	     topheader = topheader->next)
 	{
+		++ntypes;
 		if (prio_type(topheader->type)) {
 			prioheader = topheader;
 		}
@@ -1898,7 +1903,7 @@ add(qpzonedb_t *qpdb, qpznode_t *node, const dns_name_t *nodename,
 					(unsigned int)(sizeof(*newheader)),
 					qpdb->common.mctx, qpdb->common.rdclass,
 					(dns_rdatatype_t)header->type, flags,
-					&merged);
+					qpdb->maxrrperset, &merged);
 			}
 			if (result == ISC_R_SUCCESS) {
 				/*
@@ -2017,6 +2022,14 @@ add(qpzonedb_t *qpdb, qpznode_t *node, const dns_name_t *nodename,
 			/*
 			 * No rdatasets of the given type exist at the node.
 			 */
+
+			if (qpdb->maxtypepername > 0 &&
+			    ntypes >= qpdb->maxtypepername)
+			{
+				dns_slabheader_destroy(&newheader);
+				return (DNS_R_TOOMANYRECORDS);
+			}
+
 			INSIST(newheader->down == NULL);
 
 			if (prio_type(newheader->type)) {
@@ -2147,7 +2160,8 @@ loading_addrdataset(void *arg, const dns_name_t *name,
 
 	loading_addnode(loadctx, name, rdataset->type, rdataset->covers, &node);
 	result = dns_rdataslab_fromrdataset(rdataset, qpdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    qpdb->maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -4648,7 +4662,8 @@ addrdataset(dns_db_t *db, dns_dbnode_t *dbnode, dns_dbversion_t *dbversion,
 		  rdataset->covers != dns_rdatatype_nsec3)));
 
 	result = dns_rdataslab_fromrdataset(rdataset, qpdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    qpdb->maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -4767,7 +4782,8 @@ subtractrdataset(dns_db_t *db, dns_dbnode_t *dbnode, dns_dbversion_t *dbversion,
 
 	dns_name_copy(&node->name, nodename);
 	result = dns_rdataslab_fromrdataset(rdataset, qpdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    0);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -5277,6 +5293,24 @@ addglue(dns_db_t *db, dns_dbversion_t *dbversion, dns_rdataset_t *rdataset,
 	return (ISC_R_SUCCESS);
 }
 
+static void
+setmaxrrperset(dns_db_t *db, uint32_t value) {
+	qpzonedb_t *qpdb = (qpzonedb_t *)db;
+
+	REQUIRE(VALID_QPZONE(qpdb));
+
+	qpdb->maxrrperset = value;
+}
+
+static void
+setmaxtypepername(dns_db_t *db, uint32_t value) {
+	qpzonedb_t *qpdb = (qpzonedb_t *)db;
+
+	REQUIRE(VALID_QPZONE(qpdb));
+
+	qpdb->maxtypepername = value;
+}
+
 static dns_dbmethods_t qpdb_zonemethods = {
 	.destroy = qpdb_destroy,
 	.beginload = beginload,
@@ -5310,6 +5344,8 @@ static dns_dbmethods_t qpdb_zonemethods = {
 	.addglue = addglue,
 	.deletedata = deletedata,
 	.nodefullname = nodefullname,
+	.setmaxrrperset = setmaxrrperset,
+	.setmaxtypepername = setmaxtypepername,
 };
 
 static void

lib/dns/rbt-cachedb.c

@@ -1582,6 +1582,8 @@ dns_dbmethods_t dns__rbtdb_cachemethods = {
 	.unlocknode = dns__rbtdb_unlocknode,
 	.expiredata = expiredata,
 	.deletedata = dns__rbtdb_deletedata,
+	.setmaxrrperset = dns__rbtdb_setmaxrrperset,
+	.setmaxtypepername = dns__rbtdb_setmaxtypepername,
 };
 
 /*

lib/dns/rbt-zonedb.c

@@ -1749,7 +1749,8 @@ loading_addrdataset(void *arg, const dns_name_t *name,
 	}
 
 	result = dns_rdataslab_fromrdataset(rdataset, rbtdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    rbtdb->maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -2418,6 +2419,8 @@ dns_dbmethods_t dns__rbtdb_zonemethods = {
 	.addglue = addglue,
 	.deletedata = dns__rbtdb_deletedata,
 	.nodefullname = dns__rbtdb_nodefullname,
+	.setmaxrrperset = dns__rbtdb_setmaxrrperset,
+	.setmaxtypepername = dns__rbtdb_setmaxtypepername,
 };
 
 void

lib/dns/rbtdb.c

@@ -2566,6 +2566,7 @@ dns__rbtdb_add(dns_rbtdb_t *rbtdb, dns_rbtnode_t *rbtnode,
 	dns_typepair_t negtype = 0, sigtype;
 	dns_trust_t trust;
 	int idx;
+	uint32_t ntypes = 0;
 
 	if ((options & DNS_DBADD_MERGE) != 0) {
 		REQUIRE(rbtversion != NULL);
@@ -2618,6 +2619,7 @@ dns__rbtdb_add(dns_rbtdb_t *rbtdb, dns_rbtnode_t *rbtnode,
 				{
 					mark_ancient(topheader);
 				}
+				ntypes = 0; /* Always add the negative entry */
 				goto find_header;
 			}
 			/*
@@ -2641,9 +2643,11 @@ dns__rbtdb_add(dns_rbtdb_t *rbtdb, dns_rbtnode_t *rbtnode,
 			 * check for an extant non-ancient NODATA ncache
 			 * entry which covers the same type as the RRSIG.
 			 */
+			ntypes = 0;
 			for (topheader = rbtnode->data; topheader != NULL;
 			     topheader = topheader->next)
 			{
+				++ntypes;
 				if ((topheader->type == RDATATYPE_NCACHEANY) ||
 				    (newheader->type == sigtype &&
 				     topheader->type ==
@@ -2686,9 +2690,11 @@ dns__rbtdb_add(dns_rbtdb_t *rbtdb, dns_rbtnode_t *rbtnode,
 		}
 	}
 
+	ntypes = 0;
 	for (topheader = rbtnode->data; topheader != NULL;
 	     topheader = topheader->next)
 	{
+		++ntypes;
 		if (prio_type(topheader->type)) {
 			prioheader = topheader;
 		}
@@ -2780,7 +2786,7 @@ find_header:
 					rbtdb->common.mctx,
 					rbtdb->common.rdclass,
 					(dns_rdatatype_t)header->type, flags,
-					&merged);
+					rbtdb->maxrrperset, &merged);
 			}
 			if (result == ISC_R_SUCCESS) {
 				/*
@@ -3082,6 +3088,14 @@ find_header:
 			/*
 			 * No rdatasets of the given type exist at the node.
 			 */
+
+			if (rbtdb->maxtypepername > 0 &&
+			    ntypes >= rbtdb->maxtypepername)
+			{
+				dns_slabheader_destroy(&newheader);
+				return (DNS_R_TOOMANYRECORDS);
+			}
+
 			INSIST(newheader->down == NULL);
 
 			if (prio_type(newheader->type)) {
@@ -3141,7 +3155,7 @@ delegating_type(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node, dns_typepair_t type) {
 }
 
 static isc_result_t
-addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader,
+addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
 	   dns_rdataset_t *rdataset) {
 	isc_result_t result;
 	dns_slabheader_proof_t *noqname = NULL;
@@ -3152,12 +3166,12 @@ addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader,
 	result = dns_rdataset_getnoqname(rdataset, &name, &neg, &negsig);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
-	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0);
+	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
 
-	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0);
+	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
@@ -3180,7 +3194,7 @@ cleanup:
 }
 
 static isc_result_t
-addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader,
+addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
 	   dns_rdataset_t *rdataset) {
 	isc_result_t result;
 	dns_slabheader_proof_t *closest = NULL;
@@ -3191,12 +3205,12 @@ addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader,
 	result = dns_rdataset_getclosest(rdataset, &name, &neg, &negsig);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
 
-	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0);
+	result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
 
-	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0);
+	result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		goto cleanup;
 	}
@@ -3272,7 +3286,8 @@ dns__rbtdb_addrdataset(dns_db_t *db, dns_dbnode_t *node,
 	}
 
 	result = dns_rdataslab_fromrdataset(rdataset, rbtdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    rbtdb->maxrrperset);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -3329,7 +3344,7 @@ dns__rbtdb_addrdataset(dns_db_t *db, dns_dbnode_t *node,
 		}
 		if ((rdataset->attributes & DNS_RDATASETATTR_NOQNAME) != 0) {
 			result = addnoqname(rbtdb->common.mctx, newheader,
-					    rdataset);
+					    rbtdb->maxrrperset, rdataset);
 			if (result != ISC_R_SUCCESS) {
 				dns_slabheader_destroy(&newheader);
 				return (result);
@@ -3337,7 +3352,7 @@ dns__rbtdb_addrdataset(dns_db_t *db, dns_dbnode_t *node,
 		}
 		if ((rdataset->attributes & DNS_RDATASETATTR_CLOSEST) != 0) {
 			result = addclosest(rbtdb->common.mctx, newheader,
-					    rdataset);
+					    rbtdb->maxrrperset, rdataset);
 			if (result != ISC_R_SUCCESS) {
 				dns_slabheader_destroy(&newheader);
 				return (result);
@@ -3487,7 +3502,8 @@ dns__rbtdb_subtractrdataset(dns_db_t *db, dns_dbnode_t *node,
 	dns__rbtdb_nodefullname(db, node, nodename);
 
 	result = dns_rdataslab_fromrdataset(rdataset, rbtdb->common.mctx,
-					    &region, sizeof(dns_slabheader_t));
+					    &region, sizeof(dns_slabheader_t),
+					    0);
 	if (result != ISC_R_SUCCESS) {
 		return (result);
 	}
@@ -4957,3 +4973,21 @@ expire_ttl_headers(dns_rbtdb_t *rbtdb, unsigned int locknum,
 					   dns_expire_ttl DNS__DB_FLARG_PASS);
 	}
 }
+
+void
+dns__rbtdb_setmaxrrperset(dns_db_t *db, uint32_t value) {
+	dns_rbtdb_t *rbtdb = (dns_rbtdb_t *)db;
+
+	REQUIRE(VALID_RBTDB(rbtdb));
+
+	rbtdb->maxrrperset = value;
+}
+
+void
+dns__rbtdb_setmaxtypepername(dns_db_t *db, uint32_t maxtypepername) {
+	dns_rbtdb_t *rbtdb = (dns_rbtdb_t *)db;
+
+	REQUIRE(VALID_RBTDB(rbtdb));
+
+	rbtdb->maxtypepername = maxtypepername;
+}

lib/dns/rbtdb_p.h

@@ -114,6 +114,8 @@ struct dns_rbtdb {
 	uint32_t current_serial;
 	uint32_t least_serial;
 	uint32_t next_serial;
+	uint32_t maxrrperset;
+	uint32_t maxtypepername;
 	dns_rbtdb_version_t *current_version;
 	dns_rbtdb_version_t *future_version;
 	rbtdb_versionlist_t open_versions;
@@ -427,6 +429,18 @@ dns__rbtdb_setttl(dns_slabheader_t *header, dns_ttl_t newttl);
  * also update the TTL heap accordingly.
  */
 
+void
+dns__rbtdb_setmaxrrperset(dns_db_t *db, uint32_t maxrrperset);
+/*%<
+ * Set the max RRs per RRset limit.
+ */
+
+void
+dns__rbtdb_setmaxtypepername(dns_db_t *db, uint32_t maxtypepername);
+/*%<
+ * Set the max RRs per RRset limit.
+ */
+
 /*
  * Functions specific to zone databases that are also called from rbtdb.c.
  */

lib/dns/rdataslab.c

@@ -168,7 +168,8 @@ fillin_offsets(unsigned char *offsetbase, unsigned int *offsettable,
 
 isc_result_t
 dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
-			   isc_region_t *region, unsigned int reservelen) {
+			   isc_region_t *region, unsigned int reservelen,
+			   uint32_t maxrrperset) {
 	/*
 	 * Use &removed as a sentinel pointer for duplicate
 	 * rdata as rdata.data == NULL is valid.
@@ -208,6 +209,10 @@ dns_rdataslab_fromrdataset(dns_rdataset_t *rdataset, isc_mem_t *mctx,
 		return (ISC_R_SUCCESS);
 	}
 
+	if (maxrrperset > 0 && nitems > maxrrperset) {
+		return (DNS_R_TOOMANYRECORDS);
+	}
+
 	if (nitems > 0xffff) {
 		return (ISC_R_NOSPACE);
 	}
@@ -515,7 +520,8 @@ isc_result_t
 dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
 		    unsigned int reservelen, isc_mem_t *mctx,
 		    dns_rdataclass_t rdclass, dns_rdatatype_t type,
-		    unsigned int flags, unsigned char **tslabp) {
+		    unsigned int flags, uint32_t maxrrperset,
+		    unsigned char **tslabp) {
 	unsigned char *ocurrent = NULL, *ostart = NULL, *ncurrent = NULL;
 	unsigned char *tstart = NULL, *tcurrent = NULL, *data = NULL;
 	unsigned int ocount, ncount, count, olength, tlength, tcount, length;
@@ -554,6 +560,10 @@ dns_rdataslab_merge(unsigned char *oslab, unsigned char *nslab,
 #endif /* if DNS_RDATASET_FIXED */
 	INSIST(ocount > 0 && ncount > 0);
 
+	if (maxrrperset > 0 && ocount + ncount > maxrrperset) {
+		return (DNS_R_TOOMANYRECORDS);
+	}
+
 #if DNS_RDATASET_FIXED
 	oncount = ncount;
 #endif /* if DNS_RDATASET_FIXED */

lib/dns/view.c

@@ -643,6 +643,9 @@ dns_view_setcache(dns_view_t *view, dns_cache_t *cache, bool shared) {
 	dns_cache_attach(cache, &view->cache);
 	dns_cache_attachdb(cache, &view->cachedb);
 	INSIST(DNS_DB_VALID(view->cachedb));
+
+	dns_cache_setmaxrrperset(view->cache, view->maxrrperset);
+	dns_cache_setmaxtypepername(view->cache, view->maxtypepername);
 }
 
 bool
@@ -2336,6 +2339,24 @@ dns_view_getresolver(dns_view_t *view, dns_resolver_t **resolverp) {
 	return (result);
 }
 
+void
+dns_view_setmaxrrperset(dns_view_t *view, uint32_t value) {
+	REQUIRE(DNS_VIEW_VALID(view));
+	view->maxrrperset = value;
+	if (view->cache != NULL) {
+		dns_cache_setmaxrrperset(view->cache, value);
+	}
+}
+
+void
+dns_view_setmaxtypepername(dns_view_t *view, uint32_t value) {
+	REQUIRE(DNS_VIEW_VALID(view));
+	view->maxtypepername = value;
+	if (view->cache != NULL) {
+		dns_cache_setmaxtypepername(view->cache, value);
+	}
+}
+
 void
 dns_view_setudpsize(dns_view_t *view, uint16_t udpsize) {
 	REQUIRE(DNS_VIEW_VALID(view));

lib/dns/zone.c

@@ -318,6 +318,8 @@ struct dns_zone {
 	uint32_t minretry;
 
 	uint32_t maxrecords;
+	uint32_t maxrrperset;
+	uint32_t maxtypepername;
 
 	dns_remote_t primaries;
 
@@ -9741,6 +9743,7 @@ cleanup:
 	}
 
 	dns_diff_clear(&_sig_diff);
+	dns_diff_clear(&post_diff);
 
 	for (i = 0; i < nkeys; i++) {
 		dst_key_free(&zone_keys[i]);
@@ -12057,6 +12060,26 @@ dns_zone_setmaxrecords(dns_zone_t *zone, uint32_t val) {
 	zone->maxrecords = val;
 }
 
+void
+dns_zone_setmaxrrperset(dns_zone_t *zone, uint32_t val) {
+	REQUIRE(DNS_ZONE_VALID(zone));
+
+	zone->maxrrperset = val;
+	if (zone->db != NULL) {
+		dns_db_setmaxrrperset(zone->db, val);
+	}
+}
+
+void
+dns_zone_setmaxtypepername(dns_zone_t *zone, uint32_t val) {
+	REQUIRE(DNS_ZONE_VALID(zone));
+
+	zone->maxtypepername = val;
+	if (zone->db != NULL) {
+		dns_db_setmaxtypepername(zone->db, val);
+	}
+}
+
 static bool
 notify_isqueued(dns_zone_t *zone, unsigned int flags, dns_name_t *name,
 		isc_sockaddr_t *addr, dns_tsigkey_t *key,
@@ -14458,6 +14481,9 @@ ns_query(dns_zone_t *zone, dns_rdataset_t *soardataset, dns_stub_t *stub) {
 				goto cleanup;
 			}
 			dns_db_setloop(stub->db, zone->loop);
+			dns_db_setmaxrrperset(stub->db, zone->maxrrperset);
+			dns_db_setmaxtypepername(stub->db,
+						 zone->maxtypepername);
 		}
 
 		result = dns_db_newversion(stub->db, &stub->version);
@@ -17514,6 +17540,8 @@ zone_replacedb(dns_zone_t *zone, dns_db_t *db, bool dump) {
 	}
 	zone_attachdb(zone, db);
 	dns_db_setloop(zone->db, zone->loop);
+	dns_db_setmaxrrperset(zone->db, zone->maxrrperset);
+	dns_db_setmaxtypepername(zone->db, zone->maxtypepername);
 	DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_LOADED | DNS_ZONEFLG_NEEDNOTIFY);
 	return (ISC_R_SUCCESS);
 
@@ -22470,7 +22498,11 @@ failure:
 		 * Something went wrong; try again in ten minutes or
 		 * after a key refresh interval, whichever is shorter.
 		 */
-		dnssec_log(zone, ISC_LOG_DEBUG(3),
+		int loglevel = ISC_LOG_DEBUG(3);
+		if (result != DNS_R_NOTLOADED) {
+			loglevel = ISC_LOG_ERROR;
+		}
+		dnssec_log(zone, loglevel,
 			   "zone_rekey failure: %s (retry in %u seconds)",
 			   isc_result_totext(result),
 			   ISC_MIN(zone->refreshkeyinterval, 600));
@@ -24153,6 +24185,8 @@ dns_zone_makedb(dns_zone_t *zone, dns_db_t **dbp) {
 	}
 
 	dns_db_setloop(db, zone->loop);
+	dns_db_setmaxrrperset(db, zone->maxrrperset);
+	dns_db_setmaxtypepername(db, zone->maxtypepername);
 
 	*dbp = db;
 

lib/isccfg/namedconf.c

@@ -2372,6 +2372,12 @@ static cfg_clausedef_t zone_clauses[] = {
 	{ "max-records", &cfg_type_uint32,
 	  CFG_ZONE_PRIMARY | CFG_ZONE_SECONDARY | CFG_ZONE_MIRROR |
 		  CFG_ZONE_STUB | CFG_ZONE_STATICSTUB | CFG_ZONE_REDIRECT },
+	{ "max-records-per-type", &cfg_type_uint32,
+	  CFG_ZONE_PRIMARY | CFG_ZONE_SECONDARY | CFG_ZONE_MIRROR |
+		  CFG_ZONE_STUB | CFG_ZONE_STATICSTUB | CFG_ZONE_REDIRECT },
+	{ "max-types-per-name", &cfg_type_uint32,
+	  CFG_ZONE_PRIMARY | CFG_ZONE_SECONDARY | CFG_ZONE_MIRROR |
+		  CFG_ZONE_STUB | CFG_ZONE_STATICSTUB | CFG_ZONE_REDIRECT },
 	{ "max-refresh-time", &cfg_type_uint32,
 	  CFG_ZONE_SECONDARY | CFG_ZONE_MIRROR | CFG_ZONE_STUB },
 	{ "max-retry-time", &cfg_type_uint32,

lib/ns/update.c

@@ -3160,9 +3160,18 @@ update_action(void *arg) {
 						dns_diff_clear(&ctx.add_diff);
 						goto failure;
 					}
-					CHECK(update_one_rr(db, ver, &diff,
-							    DNS_DIFFOP_ADD,
-							    name, ttl, &rdata));
+					result = update_one_rr(
+						db, ver, &diff, DNS_DIFFOP_ADD,
+						name, ttl, &rdata);
+					if (result != ISC_R_SUCCESS) {
+						update_log(client, zone,
+							   LOGLEVEL_PROTOCOL,
+							   "adding an RR "
+							   "failed: %s",
+							   isc_result_totext(
+								   result));
+						goto failure;
+					}
 				}
 			}
 		} else if (update_class == dns_rdataclass_any) {