Adding upstream version 1:9.16.44.upstream/1%9.16.44

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

15 files changed, 1077 insertions, 0 deletions

diff --git a/bin/tests/system/reclimit/README b/bin/tests/system/reclimit/README
new file mode 100644
index 0000000..e474907
--- /dev/null
+++ b/bin/tests/system/reclimit/README
@@ -0,0 +1,19 @@
+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.
+
+system test for recursion limits
+
+ns1  -- root server
+ans2 -- for example.org: delegate to ns1.(n+1).example.org for all n, up to the
+                         value specified in ans.limit (or forever if limit is 0)
+ns3  -- resolver under test
+ans4 -- for ns*.example.com: return address records.
+ans7 -- "victim" server
diff --git a/bin/tests/system/reclimit/ans2/ans.pl b/bin/tests/system/reclimit/ans2/ans.pl
new file mode 100644
index 0000000..4576951
--- /dev/null
+++ b/bin/tests/system/reclimit/ans2/ans.pl
@@ -0,0 +1,235 @@
+#!/usr/bin/env perl
+
+# 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.
+
+use strict;
+use warnings;
+
+use IO::File;
+use IO::Socket;
+use Net::DNS;
+
+my $localaddr = "10.53.0.2";
+my $limit = getlimit();
+my $no_more_waiting = 0;
+my @delayed_response;
+my $timeout;
+
+my $localport = int($ENV{'PORT'});
+if (!$localport) { $localport = 5300; }
+
+my $udpsock = IO::Socket::INET->new(LocalAddr => "$localaddr",
+   LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!";
+
+my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
+print $pidf "$$\n" or die "cannot write pid file: $!";
+$pidf->close or die "cannot close pid file: $!";
+sub rmpid { unlink "ans.pid"; exit 1; };
+
+$SIG{INT} = \&rmpid;
+$SIG{TERM} = \&rmpid;
+
+my $count = 0;
+my $send_response = 0;
+
+sub getlimit {
+    if ( -e "ans.limit") {
+	open(FH, "<", "ans.limit");
+	my $line = <FH>;
+	chomp $line;
+	close FH;
+	if ($line =~ /^\d+$/) {
+	    return $line;
+	}
+    }
+
+    return 0;
+}
+
+# If $wait == 0 is returned, returned reply will be sent immediately.
+# If $wait == 1 is returned, sending the returned reply might be delayed; see
+# comments inside handle_UDP() for details.
+sub reply_handler {
+    my ($qname, $qclass, $qtype) = @_;
+    my ($rcode, @ans, @auth, @add, $wait);
+
+    print ("request: $qname/$qtype\n");
+    STDOUT->flush();
+
+    $wait = 0;
+    $count += 1;
+
+    if ($qname eq "count" ) {
+	if ($qtype eq "TXT") {
+	    my ($ttl, $rdata) = (0, "$count");
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	    print ("\tcount: $count\n");
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "reset" ) {
+	$count = 0;
+	$send_response = 0;
+	$limit = getlimit();
+	$rcode = "NOERROR";
+	print ("\tlimit: $limit\n");
+    } elsif ($qname eq "direct.example.org" ) {
+	if ($qtype eq "A") {
+	    my ($ttl, $rdata) = (3600, $localaddr);
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "indirect1.example.org" ||
+	     $qname eq "indirect2.example.org" ||
+	     $qname eq "indirect3.example.org" ||
+	     $qname eq "indirect4.example.org" ||
+	     $qname eq "indirect5.example.org" ||
+	     $qname eq "indirect6.example.org" ||
+	     $qname eq "indirect7.example.org" ||
+	     $qname eq "indirect8.example.org") {
+	if (! $send_response) {
+	    my $rr = new Net::DNS::RR("$qname 86400 $qclass NS ns1.1.example.org");
+	    push @auth, $rr;
+	} elsif ($qtype eq "A") {
+	    my ($ttl, $rdata) = (3600, $localaddr);
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname =~ /^ns1\.(\d+)\.example\.org$/) {
+	my $next = $1 + 1;
+	$wait = 1;
+	if ($limit == 0 || (! $send_response && $next <= $limit)) {
+	    my $rr = new Net::DNS::RR("$1.example.org 86400 $qclass NS ns1.$next.example.org");
+	    push @auth, $rr;
+	} else {
+	    $send_response = 1;
+	    if ($qtype eq "A") {
+		my ($ttl, $rdata) = (3600, "10.53.0.4");
+		my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+		print("\tresponse: $qname $ttl $qclass $qtype $rdata\n");
+		push @ans, $rr;
+	    }
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "direct.example.net" ) {
+	if ($qtype eq "A") {
+	    my ($ttl, $rdata) = (3600, $localaddr);
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	}
+	$rcode = "NOERROR";
+    } elsif( $qname =~ /^ns1\.(\d+)\.example\.net$/ ) {
+	my $next = ($1 + 1) * 16;
+	for (my $i = 1; $i < 16; $i++) {
+	    my $s = $next + $i;
+	    my $rr = new Net::DNS::RR("$1.example.net 86400 $qclass NS ns1.$s.example.net");
+	    push @auth, $rr;
+	    $rr = new Net::DNS::RR("ns1.$s.example.net 86400 $qclass A 10.53.0.7");
+	    push @add, $rr;
+	}
+	$rcode = "NOERROR";
+    } else {
+	$rcode = "NXDOMAIN";
+    }
+
+    return ($rcode, \@ans, \@auth, \@add, $wait);
+}
+
+sub handleUDP {
+	my ($buf, $peer) = @_;
+	my ($request, $rcode, $ans, $auth, $add, $wait);
+
+	$request = new Net::DNS::Packet(\$buf, 0);
+	$@ and die $@;
+
+	my ($question) = $request->question;
+	my $qname = $question->qname;
+	my $qclass = $question->qclass;
+	my $qtype = $question->qtype;
+
+	($rcode, $ans, $auth, $add, $wait) = reply_handler($qname, $qclass, $qtype);
+
+	my $reply = $request->reply();
+
+	$reply->header->rcode($rcode);
+	$reply->header->aa(@$ans ? 1 : 0);
+	$reply->header->id($request->header->id);
+	$reply->{answer} = $ans if $ans;
+	$reply->{authority} = $auth if $auth;
+	$reply->{additional} = $add if $add;
+
+	if ($wait) {
+		# reply_handler() asked us to delay sending this reply until
+		# another reply with $wait == 1 is generated or a timeout
+		# occurs.
+		if (@delayed_response) {
+			# A delayed reply is already queued, so we can now send
+			# both the delayed reply and the current reply.
+			send_delayed_response();
+			return $reply;
+		} elsif ($no_more_waiting) {
+			# It was determined before that there is no point in
+			# waiting for "accompanying" queries.  Thus, send the
+			# current reply immediately.
+			return $reply;
+		} else {
+			# No delayed reply is queued and the client is expected
+			# to send an "accompanying" query shortly.  Do not send
+			# the current reply right now, just save it for later
+			# and wait for an "accompanying" query to be received.
+			@delayed_response = ($reply, $peer);
+			$timeout = 0.5;
+			return;
+		}
+	} else {
+		# Send reply immediately.
+		return $reply;
+	}
+}
+
+sub send_delayed_response {
+	my ($reply, $peer) = @delayed_response;
+	# Truncation to 512 bytes is required for triggering "NS explosion" on
+	# builds without IPv6 support
+	$udpsock->send($reply->data(512), 0, $peer);
+	undef @delayed_response;
+	undef $timeout;
+}
+
+# Main
+my $rin;
+my $rout;
+for (;;) {
+	$rin = '';
+	vec($rin, fileno($udpsock), 1) = 1;
+
+	select($rout = $rin, undef, undef, $timeout);
+
+	if (vec($rout, fileno($udpsock), 1)) {
+		my ($buf, $peer, $reply);
+		$udpsock->recv($buf, 512);
+		$peer = $udpsock->peername();
+		$reply = handleUDP($buf, $peer);
+		# Truncation to 512 bytes is required for triggering "NS
+		# explosion" on builds without IPv6 support
+		$udpsock->send($reply->data(512), 0, $peer) if $reply;
+	} else {
+		# An "accompanying" query was expected to come in, but did not.
+		# Assume the client never sends "accompanying" queries to
+		# prevent pointlessly waiting for them ever again.
+		$no_more_waiting = 1;
+		# Send the delayed reply to the query which caused us to wait.
+		send_delayed_response();
+	}
+}
diff --git a/bin/tests/system/reclimit/ans4/ans.pl b/bin/tests/system/reclimit/ans4/ans.pl
new file mode 100644
index 0000000..d5002aa
--- /dev/null
+++ b/bin/tests/system/reclimit/ans4/ans.pl
@@ -0,0 +1,240 @@
+#!/usr/bin/env perl
+
+# 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.
+
+use strict;
+use warnings;
+
+use IO::File;
+use IO::Socket;
+use Net::DNS;
+
+my $localaddr = "10.53.0.4";
+my $limit = getlimit();
+my $no_more_waiting = 0;
+my @delayed_response;
+my $timeout;
+
+my $localport = int($ENV{'PORT'});
+if (!$localport) { $localport = 5300; }
+
+my $udpsock = IO::Socket::INET->new(LocalAddr => "$localaddr",
+   LocalPort => $localport, Proto => "udp", Reuse => 1) or die "$!";
+
+my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
+print $pidf "$$\n" or die "cannot write pid file: $!";
+$pidf->close or die "cannot close pid file: $!";
+sub rmpid { unlink "ans.pid"; exit 1; };
+
+$SIG{INT} = \&rmpid;
+$SIG{TERM} = \&rmpid;
+
+my $count = 0;
+my $send_response = 1;
+
+sub getlimit {
+    if ( -e "ans.limit") {
+	open(FH, "<", "ans.limit");
+	my $line = <FH>;
+	chomp $line;
+	close FH;
+	if ($line =~ /^\d+$/) {
+	    return $line;
+	}
+    }
+
+    return 0;
+}
+
+# If $wait == 0 is returned, returned reply will be sent immediately.
+# If $wait == 1 is returned, sending the returned reply might be delayed; see
+# comments inside handle_UDP() for details.
+sub reply_handler {
+    my ($qname, $qclass, $qtype) = @_;
+    my ($rcode, @ans, @auth, @add, $wait);
+
+    print ("request: $qname/$qtype\n");
+    STDOUT->flush();
+
+    $wait = 0;
+    $count += 1;
+
+    if ($qname eq "count" ) {
+	if ($qtype eq "TXT") {
+	    my ($ttl, $rdata) = (0, "$count");
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	    print ("\tcount: $count\n");
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "reset" ) {
+	$count = 0;
+	$send_response = 1;
+	$limit = getlimit();
+	$rcode = "NOERROR";
+	print ("\tlimit: $limit\n");
+    } elsif ($qname eq "direct.example.org" ) {
+	if ($qtype eq "A") {
+	    my ($ttl, $rdata) = (3600, $localaddr);
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	    print ("\twait=$wait ans: $qname $ttl $qclass $qtype $rdata\n");
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "indirect1.example.org" ||
+	     $qname eq "indirect2.example.org" ||
+	     $qname eq "indirect3.example.org" ||
+	     $qname eq "indirect4.example.org" ||
+	     $qname eq "indirect5.example.org" ||
+	     $qname eq "indirect6.example.org" ||
+	     $qname eq "indirect7.example.org" ||
+	     $qname eq "indirect8.example.org") {
+	if ($qtype eq "A") {
+	    my ($ttl, $rdata) = (3600, $localaddr);
+	    my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+	    push @ans, $rr;
+	    print ("\twait=$wait ans: $qname $ttl $qclass $qtype $rdata\n");
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname =~ /^ns1\.(\d+)\.example\.org$/) {
+	my $next = $1 + 1;
+	$wait = 1;
+	if ($limit == 0) {
+	    my $rr = new Net::DNS::RR("$1.example.org 86400 $qclass NS ns1.$next.example.org");
+	    push @auth, $rr;
+	    print ("\twait=$wait auth: $1.example.org 86400 $qclass NS ns1.$next.example.org\n");
+	} else {
+	    $send_response = 1;
+	    if ($qtype eq "A") {
+		my ($ttl, $rdata) = (3600, $localaddr);
+		my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+		print("\tresponse: $qname $ttl $qclass $qtype $rdata\n");
+		push @ans, $rr;
+	    }
+	}
+	$rcode = "NOERROR";
+    } elsif ($qname eq "direct.example.net" ) {
+        if ($qtype eq "A") {
+            my ($ttl, $rdata) = (3600, $localaddr);
+            my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+            push @ans, $rr;
+	    print ("\twait=$wait ans: $qname $ttl $qclass $qtype $rdata\n");
+        }
+        $rcode = "NOERROR";
+    } elsif( $qname =~ /^ns1\.(\d+)\.example\.net$/ ) {
+        my $next = ($1 + 1) * 16;
+        for (my $i = 1; $i < 16; $i++) {
+            my $s = $next + $i;
+            my $rr = new Net::DNS::RR("$1.example.net 86400 $qclass NS ns1.$s.example.net");
+            push @auth, $rr;
+	    print ("\twait=$wait auth: $1.example.net 86400 $qclass NS ns1.$s.example.net\n");
+            $rr = new Net::DNS::RR("ns1.$s.example.net 86400 $qclass A 10.53.0.7");
+	    print ("\twait=$wait add: ns1.$s.example.net 86400 $qclass A 10.53.0.7\n");
+            push @add, $rr;
+        }
+        $rcode = "NOERROR";
+    } else {
+	$rcode = "NXDOMAIN";
+	    print ("\twait=$wait NXDOMAIN\n");
+    }
+
+    return ($rcode, \@ans, \@auth, \@add, $wait);
+}
+
+sub handleUDP {
+	my ($buf, $peer) = @_;
+	my ($request, $rcode, $ans, $auth, $add, $wait);
+
+	$request = new Net::DNS::Packet(\$buf, 0);
+	$@ and die $@;
+
+	my ($question) = $request->question;
+	my $qname = $question->qname;
+	my $qclass = $question->qclass;
+	my $qtype = $question->qtype;
+
+	($rcode, $ans, $auth, $add, $wait) = reply_handler($qname, $qclass, $qtype);
+
+	my $reply = $request->reply();
+
+	$reply->header->rcode($rcode);
+	$reply->header->aa(@$ans ? 1 : 0);
+	$reply->header->id($request->header->id);
+	$reply->{answer} = $ans if $ans;
+	$reply->{authority} = $auth if $auth;
+	$reply->{additional} = $add if $add;
+
+	if ($wait) {
+		# reply_handler() asked us to delay sending this reply until
+		# another reply with $wait == 1 is generated or a timeout
+		# occurs.
+		if (@delayed_response) {
+			# A delayed reply is already queued, so we can now send
+			# both the delayed reply and the current reply.
+			send_delayed_response();
+			return $reply;
+		} elsif ($no_more_waiting) {
+			# It was determined before that there is no point in
+			# waiting for "accompanying" queries.  Thus, send the
+			# current reply immediately.
+			return $reply;
+		} else {
+			# No delayed reply is queued and the client is expected
+			# to send an "accompanying" query shortly.  Do not send
+			# the current reply right now, just save it for later
+			# and wait for an "accompanying" query to be received.
+			@delayed_response = ($reply, $peer);
+			$timeout = 0.5;
+			return;
+		}
+	} else {
+		# Send reply immediately.
+		return $reply;
+	}
+}
+
+sub send_delayed_response {
+	my ($reply, $peer) = @delayed_response;
+	# Truncation to 512 bytes is required for triggering "NS explosion" on
+	# builds without IPv6 support
+	$udpsock->send($reply->data(512), 0, $peer);
+	undef @delayed_response;
+	undef $timeout;
+	print ("send_delayed_response\n");
+}
+
+# Main
+my $rin;
+my $rout;
+for (;;) {
+	$rin = '';
+	vec($rin, fileno($udpsock), 1) = 1;
+
+	select($rout = $rin, undef, undef, $timeout);
+
+	if (vec($rout, fileno($udpsock), 1)) {
+		my ($buf, $peer, $reply);
+		$udpsock->recv($buf, 512);
+		$peer = $udpsock->peername();
+		$reply = handleUDP($buf, $peer);
+		# Truncation to 512 bytes is required for triggering "NS
+		# explosion" on builds without IPv6 support
+		$udpsock->send($reply->data(512), 0, $peer) if $reply;
+	} else {
+		# An "accompanying" query was expected to come in, but did not.
+		# Assume the client never sends "accompanying" queries to
+		# prevent pointlessly waiting for them ever again.
+		$no_more_waiting = 1;
+		# Send the delayed reply to the query which caused us to wait.
+		send_delayed_response();
+	}
+}
diff --git a/bin/tests/system/reclimit/ans7/ans.pl b/bin/tests/system/reclimit/ans7/ans.pl
new file mode 100644
index 0000000..41a44a6
--- /dev/null
+++ b/bin/tests/system/reclimit/ans7/ans.pl
@@ -0,0 +1,76 @@
+#!/usr/bin/env perl
+
+# 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.
+
+use strict;
+use warnings;
+
+use IO::File;
+use Getopt::Long;
+use Net::DNS::Nameserver;
+
+my $pidf = new IO::File "ans.pid", "w" or die "cannot open pid file: $!";
+print $pidf "$$\n" or die "cannot write pid file: $!";
+$pidf->close or die "cannot close pid file: $!";
+sub rmpid { unlink "ans.pid"; exit 1; };
+
+$SIG{INT} = \&rmpid;
+$SIG{TERM} = \&rmpid;
+
+my $count = 0;
+
+my $localaddr = "10.53.0.7";
+my $localport = int($ENV{'PORT'});
+if (!$localport) { $localport = 5300; }
+my $verbose = 0;
+
+sub reply_handler {
+    my ($qname, $qclass, $qtype, $peerhost, $query, $conn) = @_;
+    my ($rcode, @ans, @auth, @add);
+
+    print ("request: $qname/$qtype\n");
+    STDOUT->flush();
+
+    $count += 1;
+
+    if ($qname eq "count" ) {
+        if ($qtype eq "TXT") {
+            my ($ttl, $rdata) = (0, "$count");
+            my $rr = new Net::DNS::RR("$qname $ttl $qclass $qtype $rdata");
+            push @ans, $rr;
+            print ("\tcount: $count\n");
+        }
+        $rcode = "NOERROR";
+    } elsif ($qname eq "reset") {
+        $count = 0;
+        $rcode = "NOERROR";
+    } else {
+        $rcode = "REFUSED";
+    }
+
+    # mark the answer as authoritative (by setting the 'aa' flag
+    return ($rcode, \@ans, \@auth, \@add, { aa => 1 });
+}
+
+GetOptions(
+    'port=i' => \$localport,
+    'verbose!' => \$verbose,
+);
+
+my $ns = Net::DNS::Nameserver->new(
+    LocalAddr => $localaddr,
+    LocalPort => $localport,
+    ReplyHandler => \&reply_handler,
+    Verbose => $verbose,
+);
+
+$ns->main_loop;
diff --git a/bin/tests/system/reclimit/clean.sh b/bin/tests/system/reclimit/clean.sh
new file mode 100644
index 0000000..0a92f90
--- /dev/null
+++ b/bin/tests/system/reclimit/clean.sh
@@ -0,0 +1,22 @@
+#!/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.
+
+rm -f dig.out*
+rm -f ans?/ans.run
+rm -f ans2/ans.limit
+rm -f ans4/ans.limit
+rm -f ns?/named.memstats
+rm -f ns?/named.run
+rm -f ns*/named.conf
+rm -f ns*/named.lock
+rm -f ns*/managed-keys.bind*
diff --git a/bin/tests/system/reclimit/ns1/named.conf.in b/bin/tests/system/reclimit/ns1/named.conf.in
new file mode 100644
index 0000000..63cb706
--- /dev/null
+++ b/bin/tests/system/reclimit/ns1/named.conf.in
@@ -0,0 +1,27 @@
+/*
+ * 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 10.53.0.1;
+	notify-source 10.53.0.1;
+	transfer-source 10.53.0.1;
+	port @PORT@;
+	pid-file "named.pid";
+	listen-on { 10.53.0.1; };
+	listen-on-v6 { none; };
+	recursion no;
+	dnssec-validation no;
+};
+
+zone "." { type primary; file "root.db"; };
diff --git a/bin/tests/system/reclimit/ns1/root.db b/bin/tests/system/reclimit/ns1/root.db
new file mode 100644
index 0000000..412715c
--- /dev/null
+++ b/bin/tests/system/reclimit/ns1/root.db
@@ -0,0 +1,21 @@
+; 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.
+
+. 60 IN SOA ns.nil. hostmaster.ns.nil. 1 0 0 0 0
+. 60 IN NS ns.nil.
+ns.nil. 60 IN A 10.53.0.1
+ns.tld1. 60 IN A 10.53.0.1
+example.org. 60 IN NS direct.example.org.
+direct.example.org. 60 IN A 10.53.0.2
+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
diff --git a/bin/tests/system/reclimit/ns3/hints.db b/bin/tests/system/reclimit/ns3/hints.db
new file mode 100644
index 0000000..c9264bf
--- /dev/null
+++ b/bin/tests/system/reclimit/ns3/hints.db
@@ -0,0 +1,13 @@
+; 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.
+
+. 60 IN NS ns.nil.
+ns.nil. 60 IN A 10.53.0.1
diff --git a/bin/tests/system/reclimit/ns3/named1.conf.in b/bin/tests/system/reclimit/ns3/named1.conf.in
new file mode 100644
index 0000000..3eaaf6a
--- /dev/null
+++ b/bin/tests/system/reclimit/ns3/named1.conf.in
@@ -0,0 +1,39 @@
+/*
+ * 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;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm hmac-sha256;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };
diff --git a/bin/tests/system/reclimit/ns3/named2.conf.in b/bin/tests/system/reclimit/ns3/named2.conf.in
new file mode 100644
index 0000000..12bf35f
--- /dev/null
+++ b/bin/tests/system/reclimit/ns3/named2.conf.in
@@ -0,0 +1,39 @@
+/*
+ * 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 5;
+	recursion yes;
+	dnssec-validation yes;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm hmac-sha256;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };
diff --git a/bin/tests/system/reclimit/ns3/named3.conf.in b/bin/tests/system/reclimit/ns3/named3.conf.in
new file mode 100644
index 0000000..0910f94
--- /dev/null
+++ b/bin/tests/system/reclimit/ns3/named3.conf.in
@@ -0,0 +1,40 @@
+/*
+ * 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 100;
+	max-recursion-queries 50;
+	recursion yes;
+	dnssec-validation yes;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm hmac-sha256;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };
diff --git a/bin/tests/system/reclimit/ns3/named4.conf.in b/bin/tests/system/reclimit/ns3/named4.conf.in
new file mode 100644
index 0000000..84b5f4b
--- /dev/null
+++ b/bin/tests/system/reclimit/ns3/named4.conf.in
@@ -0,0 +1,40 @@
+/*
+ * 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 100;
+	max-recursion-queries 40;
+	recursion yes;
+	dnssec-validation yes;
+};
+
+key rndc_key {
+	secret "1234abcd8765";
+	algorithm hmac-sha256;
+};
+
+controls {
+	inet 10.53.0.3 port @CONTROLPORT@ allow { any; } keys { rndc_key; };
+};
+
+zone "." { type hint; file "hints.db"; };
diff --git a/bin/tests/system/reclimit/prereq.sh b/bin/tests/system/reclimit/prereq.sh
new file mode 100644
index 0000000..8c587c3
--- /dev/null
+++ b/bin/tests/system/reclimit/prereq.sh
@@ -0,0 +1,37 @@
+#!/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.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    if $PERL -e 'use Net::DNS; die if ($Net::DNS::VERSION <= 0.78);' 2>/dev/null
+    then
+        :
+    else
+        echo_i "Net::DNS versions up to 0.78 have a bug that causes this test to fail: please update." >&2
+        exit 1
+    fi
+else
+    echo_i "This test requires the Net::DNS library." >&2
+    exit 1
+fi
+
+if $PERL -e 'use Net::DNS::Nameserver;' 2>/dev/null
+then
+    :
+else
+    echo_i "This test requires the Net::DNS::Nameserver library." >&2
+    exit 1
+fi
diff --git a/bin/tests/system/reclimit/setup.sh b/bin/tests/system/reclimit/setup.sh
new file mode 100644
index 0000000..5b39cdf
--- /dev/null
+++ b/bin/tests/system/reclimit/setup.sh
@@ -0,0 +1,18 @@
+#!/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.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+copy_setports ns1/named.conf.in ns1/named.conf
+copy_setports ns3/named1.conf.in ns3/named.conf
diff --git a/bin/tests/system/reclimit/tests.sh b/bin/tests/system/reclimit/tests.sh
new file mode 100644
index 0000000..7fe8ee9
--- /dev/null
+++ b/bin/tests/system/reclimit/tests.sh
@@ -0,0 +1,211 @@
+#!/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.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+DIGOPTS="-p ${PORT}"
+
+status=0
+n=0
+
+ns3_reset() {
+	copy_setports $1 ns3/named.conf
+	$RNDC -c ../common/rndc.conf -s 10.53.0.3 -p ${CONTROLPORT} reconfig 2>&1 | sed 's/^/I:ns3 /'
+	$RNDC -c ../common/rndc.conf -s 10.53.0.3 -p ${CONTROLPORT} flush | sed 's/^/I:ns3 /'
+}
+
+ns3_sends_aaaa_queries() {
+	if grep "started AAAA fetch" ns3/named.run >/dev/null; then
+		return 0
+	else
+		return 1
+	fi
+}
+
+# Check whether the number of queries ans2 received from ns3 (this value is
+# read from dig output stored in file $1) is as expected.  The expected query
+# count is variable:
+#   - if ns3 sends AAAA queries, the query count should equal $2,
+#   - if ns3 does not send AAAA queries, the query count should equal $3.
+check_query_count() {
+	count1=`sed 's/[^0-9]//g;' $1`
+	count2=`sed 's/[^0-9]//g;' $2`
+	count=`expr $count1 + $count2`
+	#echo_i "count1=$count1 count2=$count2 count=$count"
+	expected_count_with_aaaa=$3
+	expected_count_without_aaaa=$4
+
+	if ns3_sends_aaaa_queries; then
+		expected_count=$expected_count_with_aaaa
+	else
+		expected_count=$expected_count_without_aaaa
+	fi
+
+	if [ $count -ne $expected_count ]; then
+		echo_i "count $count (actual) != $expected_count (expected)"
+		ret=1
+	fi
+}
+
+echo_i "set max-recursion-depth=12"
+
+n=`expr $n + 1`
+echo_i "attempt excessive-depth lookup ($n)"
+ret=0
+echo "1000" > ans2/ans.limit
+echo "1000" > ans4/ans.limit
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.4 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect1.example.org > dig.out.1.test$n || ret=1
+grep "status: SERVFAIL" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.4 count txt > dig.out.4.test$n || ret=1
+check_query_count dig.out.2.test$n dig.out.4.test$n 27 14
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+n=`expr $n + 1`
+echo_i "attempt permissible lookup ($n)"
+ret=0
+echo "12" > ans2/ans.limit
+echo "12" > ans4/ans.limit
+ns3_reset ns3/named1.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.4 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect2.example.org > dig.out.1.test$n || ret=1
+grep "status: NOERROR" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.4 count txt > dig.out.4.test$n || ret=1
+check_query_count dig.out.2.test$n dig.out.4.test$n 50 26
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+echo_i "set max-recursion-depth=5"
+
+n=`expr $n + 1`
+echo_i "attempt excessive-depth lookup ($n)"
+ret=0
+echo "12" > ans2/ans.limit
+ns3_reset ns3/named2.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.4 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect3.example.org > dig.out.1.test$n || ret=1
+grep "status: SERVFAIL" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.4 count txt > dig.out.4.test$n || ret=1
+check_query_count dig.out.2.test$n dig.out.4.test$n 13 7
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+n=`expr $n + 1`
+echo_i "attempt permissible lookup ($n)"
+ret=0
+echo "5" > ans2/ans.limit
+echo "5" > ans4/ans.limit
+ns3_reset ns3/named2.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.4 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect4.example.org > dig.out.1.test$n || ret=1
+grep "status: NOERROR" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.4 count txt > dig.out.4.test$n || ret=1
+check_query_count dig.out.2.test$n dig.out.4.test$n 22 12
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+echo_i "set max-recursion-depth=100, max-recursion-queries=50"
+
+n=`expr $n + 1`
+echo_i "attempt excessive-queries lookup ($n)"
+ret=0
+echo "13" > ans2/ans.limit
+echo "13" > ans4/ans.limit
+ns3_reset ns3/named3.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.4 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect5.example.org > dig.out.1.test$n || ret=1
+if ns3_sends_aaaa_queries; then
+  grep "status: SERVFAIL" dig.out.1.test$n > /dev/null || ret=1
+fi
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.4 count txt > dig.out.4.test$n || ret=1
+eval count=`cat dig.out.2.test$n`
+[ $count -le 50 ] || { ret=1; echo_i "count ($count) !<= 50"; }
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+n=`expr $n + 1`
+echo_i "attempt permissible lookup ($n)"
+ret=0
+echo "12" > ans2/ans.limit
+ns3_reset ns3/named3.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect6.example.org > dig.out.1.test$n || ret=1
+grep "status: NOERROR" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+eval count=`cat dig.out.2.test$n`
+[ $count -le 50 ] || { ret=1; echo_i "count ($count) !<= 50"; }
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+echo_i "set max-recursion-depth=100, max-recursion-queries=40"
+
+n=`expr $n + 1`
+echo_i "attempt excessive-queries lookup ($n)"
+ret=0
+echo "11" > ans2/ans.limit
+ns3_reset ns3/named4.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect7.example.org > dig.out.1.test$n || ret=1
+if ns3_sends_aaaa_queries; then
+  grep "status: SERVFAIL" dig.out.1.test$n > /dev/null || ret=1
+fi
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+eval count=`cat dig.out.2.test$n`
+[ $count -le 40 ] || { ret=1; echo_i "count ($count) !<= 40"; }
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+n=`expr $n + 1`
+echo_i "attempt permissible lookup ($n)"
+ret=0
+echo "9" > ans2/ans.limit
+ns3_reset ns3/named4.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS @10.53.0.3 indirect8.example.org > dig.out.1.test$n || ret=1
+grep "status: NOERROR" dig.out.1.test$n > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+eval count=`cat dig.out.2.test$n`
+[ $count -le 40 ] || { ret=1; echo_i "count ($count) !<= 40"; }
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+n=`expr $n + 1`
+echo_i "attempting NS explosion ($n)"
+ret=0
+ns3_reset ns3/named4.conf.in
+$DIG $DIGOPTS @10.53.0.2 reset > /dev/null || ret=1
+$DIG $DIGOPTS +short @10.53.0.3 ns1.1.example.net > dig.out.1.test$n || ret=1
+$DIG $DIGOPTS +short @10.53.0.2 count txt > dig.out.2.test$n || ret=1
+eval count=`cat dig.out.2.test$n`
+[ $count -lt 50 ] || ret=1
+$DIG $DIGOPTS +short @10.53.0.7 count txt > dig.out.3.test$n || ret=1
+eval count=`cat dig.out.3.test$n`
+[ $count -lt 50 ] || { ret=1; echo_i "count ($count) !<= 50";  }
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+#grep "duplicate query" ns3/named.run
+echo_i "exit status: $status"
+[ $status -eq 0 ] || exit 1