An Attack that Goes to the Heart of Free Software

The key hack that made free software possible was a legal one: using copyright to keep software free. It did that by demanding a quid pro quo: if you use software made available under the GNU GPL, modify it and distribute it, you too must make...


The key hack that made free software possible was a legal one: using copyright to keep software free. It did that by demanding a quid pro quo: if you use software made available under the GNU GPL, modify it and distribute it, you too must make it available under the GNU GPL.

If it were possible to take software released under the GPL, modify it and release it, but without passing on the freedoms to users downstream, the entire edifice of free software would be in trouble. And that, alas, seems to be precisely what is happening in a German court case:

Tomorrow on June 21st a legal case will be heard before the District Court of Berlin which may have enormous consequences for the way that software is developed and distributed. The adversaries in the case are the manufacturer and distributor of DSL routers AVM Computersysteme Vertriebs GmbH (AVM), and Cybits AG (Cybits) which produces children's web-filtering software. Both companies use the Linux kernel, which is licensed under the GNU General Public License, version 2 (GNU GPL); a Free Software license permitting everyone to use, study, share, and improve works which use it.

The case was brought to court by AVM with the aim of preventing Cybits from changing any parts of the firmware used in AVM's routers, including the Linux kernel. The Free Software Foundation Europe (FSFE) and consider AVM's action as a broad attack against the principles of Free Software, and thus against the thousands of individuals and companies developinging, improving and distributing Free Software.

"I decided to contribute my work to the Linux kernel under the GNU GPL, and let others benefit from it. I'm happy if companies make a lot of money with software written by me and thousands of others. But in return, when they distribute our software I want them to give others the same rights they received from me", said Harald Welte, founder of and copyright holder of several parts of the Linux kernel.

This is however exactly what AVM tried to avoid when in 2010 they filed two actions against Cybits. AVM claimed that when their customers install Cybits' filtering software on AVM routers it changes the routers' firmware and consequently infringes on AVM's copyright. In the opinion of AVM, even changing the Linux kernel components of the firmware is not allowed. The Court of Appeals of Berlin rejected this argument in its decision on the request for a preliminary injunction in September 2010, after Mr. Welte intervened in the case. Now, the District Court of Berlin will have to decide on the issue again, this time in the main proceedings.

IANAL, but this seems pretty clear-cut to me. AVM use GPL'd software, which it distributes. The GPL licence means that it must be made available on the same terms; that is, Cybit is perfectly entitled to take the GPL'd code, modify it, and distribute under the GPL.

The Free Software Foundation Europe has some interesting information on how AVM have tried to get around what looks like a cast-iron case against them:

First, they stated that their whole product software must be regarded as an entity under AVM copyright, and that this entity must not be modified. The position Mr Welte took was that the whole product software would in that case be a derivative work according to the GPL, and thus the whole product software should be licensed under the GNU GPL.

This seems to indicate that they don't really understand the terms of the GPL, since their "defence" would trigger the application of the GPL to the "whole product". Then they tried this:

AVM then switched to a second argument: that the software embedded on its DSL terminals consisted of several parts. According to Mr Welte, AVM could then not prohibit anyone from modifying or distributing the GPL licensed software parts.

Again, this argument is manifestly self-defeating: it the software is made up of parts, there is no way that the GPL'd elements could be released under different terms. The company's final attempt is as follows:

The final argument by AVM was that the software on their DSL terminals is a composition of several different programs, which, due to the creative process, would be a protected compilation and thus under the copyright of AVM and not affected by the copyleft of the GPL.

This sounds pretty desperate – claiming some kind of originality in the "composition of several different programs", and thus protected. And if it were accepted it would be hugely damaging for free software, since any such "original composition" of free software would then become unfree. Indeed, it might even be enough to add just a few new pieces of software alongside GPL'd software to nullify the latter's free licence.

Let's hope the German judges see through this ploy – and realise just what is at stake here. The current case is nothing less than an attempt to remove what is a key guarantee for the sustainability of the free software movement. If AVM win, the danger is that the whole legal underpinnings of free software may be seriously compromised.

Follow me @glynmoody on Twitter or

"Recommended For You"

Cisco sued by Free Software Foundation for copyright infringement Free software group slaps copyright suit on Verizon