In https://rt.cpan.org/Public/Bug/Display.html?id=43597
the autor clarified the license of this software,
though he did not add this information to the package itself yet:

On Wed Feb 25 04:08:03 2009, RSRCHBOY wrote:
> I'm looking to package Archive::Cpio for Fedora, but I can't seem to
> find the license for this package. 
> 
> Did you intend to license this package "under the same terms as Perl
> itself", that is, GPL v1+ and the Artistic License?  (or maybe the LGPL
> v2+...? :))

yeah, same as Perl. I'll try to add a mention of it in next release. thanks