Net::DNS::RR::SIG (3)

Leading comments

Automatically generated by Pod::Man 4.09 (Pod::Simple 3.35)

Standard preamble:
========================================================================

(The comments found at the beginning of the groff file "man3/Net::DNS::RR::SIG.3pm".)

NAME

Net::DNS::RR::SIG - DNS SIG resource record

SYNOPSIS

    use Net::DNS;
    $rr = new Net::DNS::RR('name SIG typecovered algorithm labels
                                orgttl sigexpiration siginception
                                keytag signame signature');

    use Net::DNS::SEC;
    $sigrr = create Net::DNS::RR::SIG( $string, $keypath,
                                        sigval => 10    # minutes
                                        );

    $sigrr->verify( $string, $keyrr ) || die $sigrr->vrfyerrstr;
    $sigrr->verify( $packet, $keyrr ) || die $sigrr->vrfyerrstr;

DESCRIPTION

Class for digital signature () resource records.

In addition to the regular methods inherited from Net::DNS::RR the class contains a method to sign packets and scalar data strings using private keys (create) and a method for verifying signatures.

The

is an implementation of See Net::DNS::RR::RRSIG for an implementation of

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

    $algorithm = $rr->algorithm;

The algorithm number field identifies the cryptographic algorithm used to create the signature.

algorithm() may also be invoked as a class method or simple function to perform mnemonic and numeric code translation.

sigexpiration and siginception times

sigex sigin sigval

    $expiration = $rr->sigexpiration;
    $expiration = $rr->sigexpiration( $value );

    $inception = $rr->siginception;
    $inception = $rr->siginception( $value );

The signature expiration and inception fields specify a validity time interval for the signature.

The value may be specified by a string with format 'yyyymmddhhmmss' or a Perl time() value.

Return values are dual-valued, providing either a string value or numerical Perl time() value.

keytag

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

The keytag field contains the key tag value of the

that validates this signature.

signame

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

The signer name field value identifies the owner name of the

that a validator is supposed to use to validate this signature.

signature

sig

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

The Signature field contains the cryptographic signature that covers the

(excluding the Signature field) and the subject data.

sigbin

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

Binary representation of the cryptographic signature.

create

Create a signature over scalar data.

    use Net::DNS::SEC;

    $keypath = '/home/olaf/keys/Kbla.foo.+001+60114.private';

    $sigrr = create Net::DNS::RR::SIG( $data, $keypath );

    $sigrr = create Net::DNS::RR::SIG( $data, $keypath,
                                        sigval => 10
                                        );
    $sigrr->print;

    # Alternatively use Net::DNS::SEC::Private 

    $private = Net::DNS::SEC::Private->new($keypath);

    $sigrr= create Net::DNS::RR::SIG( $data, $private );

create() is an alternative constructor for a

object.

This method returns a

with the signature over the data made with the private key stored in the key file.

The first argument is a scalar that contains the data to be signed.

The second argument is a string which specifies the path to a file containing the private key as generated with dnssec-keygen, a program that comes with the

distribution.

The optional remaining arguments consist of ( name => value ) pairs as follows:

        sigin  => 20161201010101,       # signature inception
        sigex  => 20161201011101,       # signature expiration
        sigval => 10,                   # validity window (minutes)

The sigin and sigex values may be specified as Perl time values or as a string with the format 'yyyymmddhhmmss'. The default for sigin is the time of signing.

The sigval argument specifies the signature validity window in minutes ( sigex = sigin + sigval ).

By default the signature is valid for 10 minutes.

*

Do not change the name of the file generated by dnssec-keygen, the create method uses the filename as generated by dnssec-keygen to determine the keyowner, algorithm and the keyid (keytag).

verify

    $verify = $sigrr->verify( $data, $keyrr );
    $verify = $sigrr->verify( $data, [$keyrr, $keyrr2, $keyrr3] );

The verify() method performs

verification of the specified data against the signature contained in the $sigrr object itself using the public key in $keyrr.

If a reference to a Net::DNS::Packet is supplied, the method performs a

verification on the packet data.

The second argument can either be a Net::DNS::RR::KEYRR object or a reference to an array of such objects. Verification will return successful as soon as one of the keys in the array leads to positive validation.

Returns false on error and sets $sig->vrfyerrstr

vrfyerrstr

    $sig0 = $packet->sigrr || die 'not signed';
    print $sig0->vrfyerrstr unless $sig0->verify( $packet, $keyrr );

    $sigrr->verify( $packet, $keyrr ) || die $sigrr->vrfyerrstr;

REMARKS

The code is not optimised for speed.

If this code is still around in 2100 (not a leap year) you will need to check for proper handling of times ...

ACKNOWLEDGMENTS

Andy Vaskys (Network Associates Laboratories) supplied the code for handling with (Algorithm 5).

T.J. Mather, the Crypt::OpenSSL::DSA maintainer, for his quick responses to bug report and feature requests.

COPYRIGHT

Copyright (c)2001-2005 Olaf M. Kolkman

Copyright (c)2007-2008 NLnet Labs, Olaf M. Kolkman

Portions Copyright (c)2014 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.

SEE ALSO

perl, Net::DNS, Net::DNS::RR, Net::DNS::SEC, Net::DNS::SEC::DSA, Net::DNS::SEC::RSA

Algorithm Numbers <www.iana.org/assignments/dns-sec-alg-numbers>

Administrator Reference Manual <www.bind9.net/manuals>