From d6c428716f702787c50695a6770f1afcaa1cdbc8 Mon Sep 17 00:00:00 2001
From: "Peter J. Holzer" <hjp@hjp.at>
Date: Sat, 16 Dec 2006 09:46:12 +0000
Subject: [PATCH] Check if the domain name in a DNS response packet matches one
 of the domain names we queried. See the thread "dnsbl or spamhaus
 occassionally blocks wrong IP" starting at 14 Mar 2006 for details.

git-svn-id: https://svn.perl.org/qpsmtpd/branches/0.3x@683 958fd67b-6ff1-0310-b445-bb7760255be9
---
 plugins/dnsbl | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/plugins/dnsbl b/plugins/dnsbl
index 6526cbd..48df98f 100644
--- a/plugins/dnsbl
+++ b/plugins/dnsbl
@@ -57,8 +57,10 @@ sub hook_connect {
 
   my $sel = IO::Select->new();
 
+  my $dom;
   for my $dnsbl (keys %dnsbl_zones) {
     # fix to find A records, if the dnsbl_zones line has a second field 20/1/04 ++msp
+    $dom->{"$reversed_ip.$dnsbl"} = 1;
     if (defined($dnsbl_zones{$dnsbl})) {
       $self->log(LOGDEBUG, "Checking $reversed_ip.$dnsbl for A record in the background");
       $sel->add($res->bgsend("$reversed_ip.$dnsbl"));
@@ -69,6 +71,7 @@ sub hook_connect {
   }
 
   $self->qp->connection->notes('dnsbl_sockets', $sel);
+  $self->qp->connection->notes('dnsbl_domains', $dom);
 
   return DECLINED;
 }
@@ -88,6 +91,7 @@ sub process_sockets {
   $res->udp_timeout(30);
 
   my $sel = $conn->notes('dnsbl_sockets') or return "";
+  my $dom = $conn->notes('dnsbl_domains');
   my $remote_ip = $self->qp->connection->remote_ip;
 
   my $result; 
@@ -110,11 +114,13 @@ sub process_sockets {
     if ($query) {
       my $a_record = 0;
       foreach my $rr ($query->answer) {
-	$a_record = 1 if $rr->type eq "A";
 	my $name = $rr->name;
+	$self->log(LOGDEBUG, "name $name");
+	next unless $dom->{$name};
+	$self->log(LOGDEBUG, "name $name was queried");
+	$a_record = 1 if $rr->type eq "A";
 	($dnsbl) = ($name =~ m/(?:\d+\.){4}(.*)/) unless $dnsbl;
 	$dnsbl = $name unless $dnsbl;
-	$self->log(LOGDEBUG, "name ", $rr->name);
 	next unless $rr->type eq "TXT";
 	$self->log(LOGDEBUG, "got txt record");
 	$result = $rr->txtdata and last;