NAME¶

Net::DNS::RR::TSIG - DNS TSIG resource record

SYNOPSIS¶

    use Net::DNS;
    $tsig = Net::DNS::RR::TSIG->create( $keyfile );
    $tsig = Net::DNS::RR::TSIG->create( $keyfile,
                                        fudge => 300
                                        );

DESCRIPTION¶

Class for DNS Transaction Signature (TSIG) resource records.

METHODS¶

The available methods are those inherited from the base class augmented by the type-specific methods defined in this package.

Use of undocumented package features or direct access to internal data structures is discouraged and could result in program termination or other unpredictable behaviour.

    $algorithm = $rr->algorithm;
    $rr->algorithm( $algorithm );

    $rr->key( $key );

    $rr->keybin( $keybin );

    $time_signed = $rr->time_signed;
    $rr->time_signed( $time_signed );

    $fudge = $rr->fudge;
    $rr->fudge( $fudge );

    $rr->mac( $mac );

    $macbin = $rr->macbin;
    $rr->macbin( $macbin );

    $prior_mac = $rr->prior_mac;
    $rr->prior_mac( $prior_mac );

    $prior_macbin = $rr->prior_macbin;
    $rr->prior_macbin( $prior_macbin );

    $request_mac = $rr->request_mac;
    $rr->request_mac( $request_mac );

    $request_macbin = $rr->request_macbin;
    $rr->request_macbin( $request_macbin );

    $original_id = $rr->original_id;
    $rr->original_id( $original_id );

     $rcode = $tsig->error;

     $other = $tsig->other;

    sub signing_function {
        my ( $keybin, $data ) = @_;
        my $hmac = Digest::HMAC->new( $keybin, 'Digest::MD5' );
        $hmac->add( $data );
        return $hmac->digest;
    }
    $tsig->sig_function( \&signing_function );

     $sigdata = $tsig->sig_data($packet);

    $tsig = Net::DNS::RR::TSIG->create( $keyfile );
    $tsig = Net::DNS::RR::TSIG->create( $keyfile,
                                        fudge => 300
                                        );

    $verify = $tsig->verify( $data );
    $verify = $tsig->verify( $packet );
    $verify = $tsig->verify( $reply,  $query );
    $verify = $tsig->verify( $packet, $prior );

TSIG Keys¶

The TSIG authentication mechanism employs shared secret keys to establish a trust relationship between two entities.

It should be noted that it is possible for more than one key to be in use simultaneously between any such pair of entities.

TSIG keys are generated using the tsig-keygen utility distributed with ISC BIND:

    tsig-keygen -a HMAC-SHA256 host1-host2.example.

Other algorithms may be substituted for HMAC-SHA256 in the above example.

These keys must be protected in a manner similar to private keys, lest a third party masquerade as one of the intended parties by forging the message authentication code (MAC).

Configuring BIND Nameserver¶

The generated key must be added to the /etc/named.conf configuration or a separate file introduced by the $INCLUDE directive:

    key "host1-host2.example. {
        algorithm hmac-sha256;
        secret "Secret+known+only+by+participating+entities=";
    };

ACKNOWLEDGMENT¶

Most of the code in the Net::DNS::RR::TSIG module was contributed by Chris Turbeville.

Support for external signing functions was added by Andrew Tridgell.

TSIG verification, BIND keyfile handling and support for HMAC-SHA1, HMAC-SHA224, HMAC-SHA256, HMAC-SHA384 and HMAC-SHA512 functions was added by Dick Franks.

BUGS¶

A 32-bit representation of time is used, contrary to RFC2845 which demands 48 bits. This design decision will need to be reviewed before the code stops working on 7 February 2106.

COPYRIGHT¶

Copyright (c)2000,2001 Michael Fuhr.

Portions Copyright (c)2002,2003 Chris Reinhardt.

Portions Copyright (c)2013,2020 Dick Franks.

All rights reserved.

Package template (c)2009,2012 O.M.Kolkman and R.W.Franks.

LICENSE¶

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific prior written permission.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

SEE ALSO¶

perl, Net::DNS, Net::DNS::RR, RFC2845-bis, RFC4635

TSIG Algorithm Names <http://www.iana.org/assignments/tsig-algorithm-names>