Re: ad hoc license: is it DFSG-conformant ?

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

Ben Finney writes ("Re: ad hoc license: is it DFSG-conformant ?"):
> One significant lack is that the permissions do not include explicit
> permission for a recipient to license the work to third parties under
> the same conditions. This fails DFSG §3.

Such a sublicensing permission is unnecessary since the licence (as
any Free licence must) gives third parties the necessary permission
directly.

To be more concrete, in this case we are imagining a Debian derivative
(Knoppix, say) redistributing a modified version of Debian's modified
version of nauty.

For this to be OK, Debian needs:

 - permission from upstream to modify and redistribute modified
    versions.  This is granted.

Knoppix needs:

 - permission from upstream for Knoppix modify and redistribute the
    modified versions.  This is granted directly to Knoppix by
    upstream in thier licence.

 - permission from the Debian contributors to (modify and)
    redistribute the modifications made for Debian.  This will
    be granted explicitly by the Debian maintainers and contributors,
    presumably on the same terms as the upstream licence (as that is
    conventional).

Ian.