From f8327c312f980f87d78ec4cf6e326eea6de5236d Mon Sep 17 00:00:00 2001
From: Florian Obser <florian@narrans.de>
Date: Sun, 23 Apr 2017 11:33:56 +0200
Subject: [PATCH] send dns updates for tlsa records

---
 dnsupdate_tlsa | 194 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)
 create mode 100755 dnsupdate_tlsa

diff --git a/dnsupdate_tlsa b/dnsupdate_tlsa
new file mode 100755
index 0000000..4daffbb
--- /dev/null
+++ b/dnsupdate_tlsa
@@ -0,0 +1,194 @@
+#! /usr/bin/perl
+# Copyright (c) 2017 Florian Obser <florian@narrans.de>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+use strict;
+use warnings;
+use 5.010;
+use autodie;
+
+use Digest::SHA;
+use Getopt::Long;
+use MIME::Base64;
+use Net::DNS;
+use Net::DNS::RR::TSIG;
+use Pod::Usage;
+
+use constant WAIT_BEGIN => 1;
+use constant WAIT_END => 2;
+use constant END_FOUND =>3;
+
+my $port = 53;
+my $ttl = 3600;
+my $help = 0;
+my ($oldcert, $cert, $tsigname, $tsigkey, $server, $verbose, $tsig);
+my ($old_rr, $new_rr, $update, $resolver, $reply);
+
+GetOptions("help|?" => \$help,
+	   "verbose" => \$verbose,
+	   "port=i" => \$port,
+	   "server=s" => \$server,
+	   "oldcert=s" => \$oldcert,
+	   "cert=s" => \$cert,
+	   "ttl=i" => \$ttl,
+	   "tsigname=s" => \$tsigname,
+	   "tsigkey=s" => \$tsigkey)
+    or die("Error in command line arguments\n");
+
+pod2usage(1) if ($help or scalar(@ARGV) != 2);
+
+my ($zone, $label) = @ARGV;
+
+if (!defined $server) {
+    say STDERR "DNS Server missing.";
+    pod2usage(1);
+}
+
+if (!defined $oldcert and !defined $cert) {
+    say STDERR "At least -oldcert or -cert must be provided";
+    pod2usage(1);
+}
+
+if (defined $oldcert) {
+    $old_rr = gen_tlsa($label, $oldcert);
+    if (!defined $old_rr) {
+	say STDERR "cannot parse $oldcert";
+	exit(1);
+    }
+}
+
+if (defined $cert) {
+    $new_rr = gen_tlsa($label, $cert);
+    if (!defined $new_rr) {
+	say STDERR "cannot parse $oldcert";
+	exit(1);
+    }
+}
+
+say "del: ", $old_rr->string  if (defined $old_rr && $verbose);
+say "add: ", $new_rr->string  if (defined $new_rr && $verbose);
+
+$update = new Net::DNS::Update($zone);
+
+if (defined $old_rr && defined $new_rr) {
+    $update->push(update => rr_del($old_rr->string), rr_add($new_rr->string));
+} elsif (defined $old_rr && !defined $new_rr) {
+    $update->push(update => rr_del($old_rr->string));
+} elsif (!defined $old_rr && defined $new_rr) {
+    $update->push(update => rr_add($new_rr->string));
+} else {
+    say STDERR "neither old nor new cert defined, don't know what to do";
+    exit(1);
+}
+
+if (defined $tsigname && defined $tsigkey) {
+    $tsig =  Net::DNS::RR::TSIG->create($tsigname, $tsigkey);
+    say $tsig->string if ($verbose);
+    $update->push( additional => $tsig);
+}
+
+say $update->string if ($verbose);
+
+$resolver = new Net::DNS::Resolver;
+$resolver->nameservers($server);
+$resolver->port($port);
+
+$reply = $resolver->send($update);
+
+if ($reply) {
+    if ( $reply->header->rcode eq 'NOERROR') {
+	say "Update succeeded" if($verbose);
+    } else {
+	say STDERR 'Update failed: ', $reply->header->rcode;
+	exit(1);
+    }
+} else {
+    say 'Update failed: ', $resolver->errorstring;
+    exit(1);
+}
+
+exit(0);
+
+sub gen_tlsa {
+    my ($label, $cert_file) = @_;
+    my $state = WAIT_BEGIN;
+    my $pem = '';
+    my ($fh, $line, $rr);
+    
+    open($fh, '<', $cert_file);
+    while($line = <$fh>) {
+	if ($state == WAIT_BEGIN) {
+	    if ($line=~/^-----BEGIN CERTIFICATE-----/) {
+		$state = WAIT_END;
+	    }
+	} elsif ($state == WAIT_END) {
+	    if ($line=~/^-----END CERTIFICATE-----/) {
+		$state = END_FOUND;
+		last;
+	    } else {
+		$pem.=$line;
+	    }
+	}
+    }
+    close($fh);
+
+    return undef if ($state != END_FOUND);
+    
+    $rr = new Net::DNS::RR(join(' ', $label, $ttl, 'IN TLSA 1 0 1',
+			   Digest::SHA::sha256_hex(decode_base64($pem))));
+    return $rr;
+}
+
+__END__
+=head1 NAME
+
+dnsupdate_tlsa - send dns updates for tlsa records
+
+=head1 SYNOPSIS
+
+dnsupdate_tlsa [options] zone dnsname
+
+ Options:
+    -help	brief help message
+    -verbose	verbose output
+    -server	DNS server
+    -port	DNS port
+    -tsigname	Name of tsig key
+    -tsigkey	tsig key
+    -oldcert	old certificate, to remote TLSA record
+    -cert	current certificate, to add TLSA record
+
+=head1 OPTIONS
+
+=over 8
+
+=item B<-help>
+
+Print a brief help message and exits.
+
+=item B<-server>
+
+DNS server to send DNS updates to.
+
+=item B<-port>
+
+DNS port to send DNS updates to, default 53.
+
+=back
+
+=head 1 DESCRIPTION
+
+B<This program> will update TLSA records.
+
+=cut