Check DNAME resolution via itself

diff --git a/bin/tests/system/chain/ans3/ans.pl b/bin/tests/system/chain/ans3/ans.pl
index 13ee65edc46aa5fa44a919f6091f2dfc3c65acc6..31d22d807b7e92bfc690ddfd00e23951b8a50e1b 100644 (file)
--- a/bin/tests/system/chain/ans3/ans.pl
+++ b/bin/tests/system/chain/ans3/ans.pl
@@ -80,6 +80,34 @@ sub reply_handler {
        $rr = new Net::DNS::RR("$synth2 $ttl $qclass DNAME .");
        push @ans, $rr;
        $rcode = "NOERROR";
+    # The following three code branches referring to the "example.dname"
+    # zone are necessary for the resolver variant of the CVE-2021-25215
+    # regression test to work.  A named instance cannot be used for
+    # serving the DNAME records below as a version of BIND vulnerable to
+    # CVE-2021-25215 would crash while answering the queries asked by
+    # the tested resolver.
+    } elsif ($qname eq "ns3.example.dname") {
+       if ($qtype eq "A") {
+               my $rr = new Net::DNS::RR("$qname $ttl $qclass A 10.53.0.3");
+               push @ans, $rr;
+       }
+       if ($qtype eq "AAAA") {
+               my $rr = new Net::DNS::RR("example.dname. $ttl $qclass SOA . . 0 0 0 0 $ttl");
+               push @auth, $rr;
+       }
+       $rcode = "NOERROR";
+    } elsif ($qname eq "self.example.self.example.dname") {
+       my $rr = new Net::DNS::RR("self.example.dname. $ttl $qclass DNAME dname.");
+       push @ans, $rr;
+       $rr = new Net::DNS::RR("$qname $ttl $qclass CNAME self.example.dname.");
+       push @ans, $rr;
+       $rcode = "NOERROR";
+    } elsif ($qname eq "self.example.dname") {
+       if ($qtype eq "DNAME") {
+               my $rr = new Net::DNS::RR("$qname $ttl $qclass DNAME dname.");
+               push @ans, $rr;
+       }
+       $rcode = "NOERROR";
     } else {
        $rcode = "REFUSED";
     }

diff --git a/bin/tests/system/chain/ns1/root.db b/bin/tests/system/chain/ns1/root.db
index bc70f8c2a0d0627f2f806b8bd92607e68657d3d4..c076a77a1e1ead7bbbefe0ae644642107c55c23a 100644 (file)
--- a/bin/tests/system/chain/ns1/root.db
+++ b/bin/tests/system/chain/ns1/root.db
@@ -24,6 +24,10 @@ ns2.example.         A       10.53.0.2
 example.broken.                NS      ns3.example.broken.
 ns3.example.broken.    A       10.53.0.3
 
+; for the resolver variant of the CVE-2021-25215 regression test
+example.dname.         NS      ns3.example.dname.
+ns3.example.dname.     A       10.53.0.3
+
 domain0.nil.           NS      ns2.domain0.nil
 domain1.nil.           NS      ns2.domain0.nil
 domain2.nil.           NS      ns2.domain0.nil

diff --git a/bin/tests/system/chain/ns2/generic.db b/bin/tests/system/chain/ns2/generic.db
index 8b9d2207dd920db13271050d903ffa0f5a04cd65..566d22265b134d69d66d7e36136e3b3744e54bd2 100644 (file)
--- a/bin/tests/system/chain/ns2/generic.db
+++ b/bin/tests/system/chain/ns2/generic.db
@@ -16,3 +16,5 @@ ns2   86400   AAAA    fd92:7065:b8e:ffff::2
 @       86400  AAAA    1:2:3::4
 *       86400  A       1.2.3.4
 *       86400  AAAA    1:2:3::4
+; CVE-2021-25215 regression test data
+self   86400   DNAME   nil.

diff --git a/bin/tests/system/chain/tests.sh b/bin/tests/system/chain/tests.sh
index a7b2bf5d9f2ea2d1e2c9d1d4d300c187ea39b46e..dc7622be6f050fbec24ab2986128e789ba1b55e5 100644 (file)
--- a/bin/tests/system/chain/tests.sh
+++ b/bin/tests/system/chain/tests.sh
@@ -295,5 +295,23 @@ grep 'status: NOERROR' dig.out.7.$n > /dev/null 2>&1 || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=`expr $status + $ret`
 
+# Regression test for CVE-2021-25215 (authoritative server).
+n=`expr $n + 1`
+echo_i "checking DNAME resolution via itself (authoritative) ($n)"
+ret=0
+$DIG $DIGOPTS @10.53.0.2 DNAME self.domain0.self.domain0.nil. > dig.out.2.$n 2>&1
+grep 'status: NOERROR' dig.out.2.$n > /dev/null 2>&1 || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
+# Regression test for CVE-2021-25215 (recursive resolver).
+n=`expr $n + 1`
+echo_i "checking DNAME resolution via itself (recursive) ($n)"
+ret=0
+$DIG $DIGOPTS @10.53.0.7 DNAME self.example.self.example.dname. > dig.out.7.$n 2>&1
+grep 'status: NOERROR' dig.out.7.$n > /dev/null 2>&1 || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1