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riders and extra restrictions on the GPL, and internal consistency

On Tue, Apr 22, 2003 at 09:41:34AM +0100, Edmund GRIMLEY EVANS wrote:
> Glenn Maynard <g_deb@zewt.org>:
> > > Well, doesn't the GPL say something on it being illegal to impose additional 
> > > restrictions on distribution?
> > 
> > If the restriction is agreed upon by all copyright holders, then the issue
> > is murky; as far as I know, there's no consensus on this issue on debian-
> > legal.  (I believe Branden Robinson claims that any such additional
> > restrictions render the license internally inconsistent, such that it's
> > impossible to satisfy, but not everyone agrees.)
> That's not what I remember.
> If the copyright holder includes a copy of the GPL but writes that the
> software is licensed under the GPL plus additional restrictions, then
> this is not "illegal" as far as I know (there's nothing in the GPL
> that prevents it from being used in this way). Of course, the
> resulting licence is not compatibile with the GPL, so if the program
> were linked with other GPL software Debian could not distribute it.

I have never asserted that adding restrictions to the GNU GPL is
"illegal".  I have asserted, as Glenn Maynard points out, that the way
most people do this -- at least in cases that have come to my attention
via the debian-legal list -- results in a license that is internally
inconsistent, and thus impossible to satisfy while exercising one's
traditional freedoms with a copyleft.  The result is that the license
never attaches, and people have only the rights that traditional
copyright law -- or, potentially, an alternative license arrangement
with the copyright holder -- grant.

It's not illegal to not have a license to copy and distribute a
copyrighted work, so you misrepresent my position by implying that I
think so.

My argument hinges on three observations.

Observation One
The scope of the terms and conditions, a.k.a. restrictions, is clearly
defined by the text of the GNU GPL.  Any restrictions beyond that are
forbidden by section six.

I'll do some snipping of the GPL text[1] to make it clear.

  6.  Each time you redistribute the Program (or any work based on the
  Program), the recipient automatically receives a license from the
  original licensor to copy, distribute or modify the Program subject to
  these terms and conditions. You may not impose any further restrictions
  on the recipients' exercise of the rights granted herein. You are not
  responsible for enforcing compliance by third parties to this License.

"...the recipient automatically receives a license from the original
licensor to copy, distribute or modify the Program subject to

It is obvious to me that "THESE TERMS AND CONDITIONS" is meant to refer

Observation Two
The FSF claims copyright in the text of the GPL itself, and does not
extend permission to anyone to modify it.

  Copyright (C) 1989, 1991 Free Software Foundation, Inc.
  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA

  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.

Therefore, making modifications to the area between "TERMS AND
AND CONDITIONS" might be considered by the FSF as an infringement of
their copyright in the text of the GNU GPL.

Observation Three
The FSF does not want people "forking" the GPL, and think that license
proliferation is a bad thing.  To the extent that they can, they
prevent proliferation of GPL-esque licenses by withholding permission
from people to modify the text of the GPL itself.

See the GPL FAQ[2]:

  Can I modify the GPL and make a modified license?
      You can use the GPL terms (possibly modified) in another license
      provided that you call your license by another name and do not
      include the GPL preamble, and provided you modify the
      instructions-for-use at the end enough to make it clearly
      different in wording and not mention GNU (though the actual
      procedure you describe may be similar).

      If you want to use our preamble in a modified license, please
      write to <licensing@gnu.org> for permission. For this purpose we
      would want to check the actual license requirements to see if we
      approve of them.

      Although we will not raise legal objections to your making a
      modified license in this way, we hope you will think twice and not
      do it. Such a modified license is almost certainly incompatible
      with the GNU GPL, and that incompatibility blocks useful
      combinations of modules. The mere proliferation of different free
      software licenses is a burden in and of itself.

We can see that it is possible to create license derivative in effect of
the GNU GPL; perhaps the FSF is cognizant of legal cases in the U.S.
that withhold copyright protection from the terms of contracts, since
they seem -- vaguely -- to be constraining the actual restriction on
modification to the preamble and instructions-for-use, which fall outside
the "TERMS AND CONDITIONS".  (While as far as I know this area is still
being litigated -- of course -- I am given to understand that many
lawyers and judges feel that it places too much on the legal system to
compel people to reword the terms of contracts, possibility introducing
ambiguity or unenforceability, to avoid infringing the copyrights of

However, in practice, most people don't do what the FSF recommends in
their FAQ.  They just say "it's under the GPL" and slap extra
restrictions somewhere else -- perhaps in a README file.  It is this
practice that I call internally inconsistent, for it demands that the
phrase "these terms and conditions" be incompletely specified as used in
the GNU GPL.  And, of course, even if one feels that this isn't a
problem, there is *still* the issue of incompatibility with all other
GPLed works in the world.  I therefore think it's a good idea for people
forking the GPL to rename the license, quite apart from whether or not
one fears criticism or suit from the FSF over it.  If your license isn't
the "GNU GPL" that everyone reads at [1] and which the Debian Project
and tons of other people tell the whole world they can get by writing to
the Free Software Foundation, then you run the risk of goading people
into infringing the copyright license you thought you were imposing.  I
am not sure that a copyright holder can be held liable for vicarious
infringement in his own work -- probably not -- but it's an unfriendly
thing to do, and the Debian Project is right to reject such licenses as
ambiguous.  It is valuable to the Free Software community that "GNU GPL"
consistently mean the same thing when people refer to it.

[1] http://www.gnu.org/copyleft/gpl.html
[2] http://www.gnu.org/copyleft/gpl-faq.html

G. Branden Robinson                |    People are equally horrified at
Debian GNU/Linux                   |    hearing the Christian religion
branden@debian.org                 |    doubted, and at seeing it
http://people.debian.org/~branden/ |    practiced.         -- Samuel Butler

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