Re: Dual-Licensing Linux Kernel with GPL V2 and GPL V3

Daniel Hazelton
2007-06-15T10:14:58Z

On Friday 15 June 2007 05:30:09 Bernd Paysan wrote:
> On Friday 15 June 2007 01:46, david@lang.hm wrote:
> > if you cannot modify the software that runs on your Tivo hardware you
> > haven't tried very hard.
>
> Yes, but the GPLv2 clearly says that you don't have to try very hard. The
> preferred form of modification has to be distributed. I can run a
> decompiler or disassembler on a program, and I can even modify it in place
> with a hex editor (I have even modified programs in embedded ROMs by using
> focussed ion beam, so I know you can modify every program if you try hard
> enough). It's certainly possible to crack Tivo's firmware to accept my own
> signature, but it's *not* the preferred form of modification, the source
> code and Tivo's key for the signature.

How is a signing key part of the "preferred form for modification"? It isn't a
requirement to *modify* anything, just to *replace* something. (And I am
*NOT* going to explain why "replace != modify" again)

> Since Tivo's firmware only accepts a signed kernel, the combination of
> kernel+signature is the binary they ship. The kernel itself is useless, the
> signature as well. Therefore, you can imply that Tivo's key is part of
> the "other stuff" the GPLv2 mentions, because you need it to recreate the
> same code as Tivo did and shipped (compilers insert timestamps and such),
> and to modify that code. The source code is just a mean, the thing they
> shipped is the end (the binary), and they have to comply with the GPL for
> that binary - which by all means of practical understanding includes the
> signature.

I can find no such requirement in the GPLv2. In fact, it actually says that
you don't even have to be able to *USE* the program. See section 12 of the
GPL if you don't believe me.

> "You can imply" means: It depends on court and legal system. I'm quite
> confident that in Germany, the legal system might favor the "GPLv2 does not
> allow tivoization" point of view, and in the USA, the legal sysem might do
> the opposite.

In light of the d-link case, I'm pretty certain that the German Courts
interpretation of the GPLv2 makes "Tivoization" a violation. In the US I can
say that the result would be "GPLv2 does not disallow tivoization". As I've
pointed out in other posts, the GPLv2 actually *limits* itself to three
specific "activities". Whether it was intended to "incidentally" cover other
things or not, it does *clearly* state what it's scope is. If that scope *IS*
*NOT* the intent of the person and/or person who authored the license, that
text *SHOULD* *NOT* exist.

DRH

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