How To Break The GPL

pvolcko at pvolcko at
Fri Mar 3 16:20:26 UTC 2000

This is very similar to the fiasco involving some Quake patches that have been
flying around (check out slashdot's archives froma  few days ago to get
links).  Basically someone had taken the GPL'd Quake source and tried to clean
up some server security problems.  They released the changes in the form of
compiled binary patches, not source.  This person also intended on not giving
his source level changes out to anyone.  

This person claimed that they were in the clear because they were not
re-distributing any of the original code in source or binary form, only binary

John Carmack took issue with this entire situation and has apparently resolved
it for the time being, however there is still some question as to if the
releasor of the patches was legally in the clear or not.

The arguments against the logic are mostly based around the fact that whether
or not the distributed material is binary only or source diffs or whatever,
the changes are based on a GPL'd code based.  In order to make the changes the
GPL'd code needed to be linked together at some point and the entire derived
program created in binary form.  As such distribution of the changes is
tantamount to distributing the entire system since it needed to be linked at
some point against the GPL'd code.  The Bainary patches, although resulting
from an individual's code changes (and are thus his property), were indeed
still a derivation of the GPL'd work.  Thus the GPL or less restricitve form
of licensing must be used as per the terms of the original program's GPL
licensing.  The patch creator doesn't need to give source for that original
system (in this case Quake), only the changes that he made.  

It boils down to trying to make a distinction between machine language patches
and source code patches.  As far as I know everyone agrees that source level
patching requires that the patches be licensed under the GPL or "less".  There
is no reason at all that the machine language version of those patches should
be excluded.  

If I made an incorrect assumtion in there (especially with regard to source
patches being subject to the requirements of the license of the base
program) please let me know.  Also, if I misrepresented the case described
above with the quake patching, accept my appologies... I was going from
memory which isn't always the smart way to go.  :)

Paul Volcko

On Fri, 3 Mar 2000, John Cowan wrote:

> This is offered in the spirit of "How To Make Atomic Bombs", and does
> *not* mean that the author approves of the conduct described herein.
> A close reading of the GPL suggests the following way to distribute
> unfree software that contains GPL-specific components.
> 1.  Alice designs, debugs, and tests (but does not distribute)
>     commercial software that uses a GPLed library that is copyrighted
>     by Trent and publicly available from Trent's homepage.
> 2.  Alice distributes a compiled version of her code *only* to her
>     paying customer, Bob, under a restrictive end-user license agreement.
>     Trent's library is not included.
> 3.  Alice sends instructions (in English, sh, or make) that cause Bob's
>     system to download Trent's library from its homepage and link it with
>     Alice's modules.
> Now who has violated Trent's copyright?  Not Alice: she did not modify or
> distribute Trent's work.  Not Bob: he cannot distribute the executable
> version because of Alice's license.  Bob might be said to have made a derivative
> work, but only in the sense that Bob would make a derivative of a book by
> Trent by writing marginal notes in a copy that he owns, a perfectly legitimate
> behavior.  Nor would it matter if Bob marked up the book in accordance
> with instructions sent him by Alice.  (If Bob tried to duplicate and sell the
> marked-up book, Trent's copyright *would* be violated, but he doesn't.)
> I would very much like to hear that there is a flaw in this logic.  If so,
> where is it?
> -- 
> Schlingt dreifach einen Kreis vom dies! || John Cowan <jcowan at>
> Schliesst euer Aug vor heiliger Schau,  ||
> Denn er genoss vom Honig-Tau,           ||
> Und trank die Milch vom Paradies.            -- Coleridge (tr. Politzer)

More information about the License-discuss mailing list