Slashdot Mirror
LWN on the Patent Encumbrence of SELinux
Anonymous Coward writes "LWN has a story about patents in SELinux. The article says: "Much of the actual work in the implementation of SELinux was done by Secure Computing Corporation (SCC). SCC, in its implementation of SELinux, used a technology that it calls type enforcement. As it turns out, SCC has a patent on this technology." Sigh.
From clause 7 at http://www.gnu.org/copyleft/gpl.html
"If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program."
No.
From clause 7 at http://www.gnu.org/copyleft/gpl.html
"If you cannot distribute so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not distribute the Program at all. For example, if a patent license would not permit royalty-free redistribution of the Program by all those who receive copies directly or indirectly through you, then the only way you could satisfy both it and this License would be to refrain entirely from distribution of the Program."
You should read the GPL. In the introduction, it states: "We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all." For the details, you should check sections 7 and 8 of the GPL.
Let's put this in a different way: if a company distributes some code for which they own a patent under the GPL, then the only way for them to comply with section 7 of the GPL is to allow royalty-free usage, redistribution and modification of the code. Otherwise, they would not be allowed to distribute the code under the GPL. They would have to stop distributing it, or change the license.
-Raphaël
I'll post the relevant section here:
The situation that the FSF had in mind was a company taking GPL code, then injecting patented code in a attempt to de-GPL it and make it proprietary. The protection provided by copyright is the leverage that enforces this.
What they didn't apparently consider was a patent owner voluntarily providing code (that they have the copyright to) under the GPL license. However, I think (I hope) the license is clear enough that if the code is GPL, it can't be retracted (even by the copyright holder) or restricted by patents.
IANAL, but I bet this is giving some FSF lawyers pause to consider whether they need an explicit clause in the GPL to cover this.
If you were blocking sigs, you wouldn't have to read this.
oever asks:
Where is the problem exactly with patents in GPL-ed software?
Worst case scenario: a patent could make it illegal to use a particular software package, even one licensed under the GPL. Depending on patent laws, it could also interfere with redistributing GPL code.
If a company has a patent on a software technique and writes and distributes GPL code to implement it, anybody can use this code. Or can't they?
Potentially not. The GPL is a copyright license, it gives people the right to distribute the software. It is not a patent license, it does not grant people the right to use any patents.
A patent holder who is friendly to the Free software community will provide, seperately from the GPL, a license permitting anyone to use, for free, the patent within the context of software licensed under a Free Software license. The DFSG makes a good set of guidelines for this purpose. Generally such licenses are void if you sue the patent holder over their use of your own patents. These are called Royalty-Free patents (or RF Patents). Some companies, whose patents are purely defensive, give a royalty-free license to everyone who isn't suing them.
To my knowledge, SCC has not done this for the patents connected to SELinux. This is why people are upset.
And can people modify that code? I guess one cannot write new GPL-ed code that does the same thing.
You can modify existing code or write new code if and only if you do so within the bounds of the above discussed patent licenses.
Or can a company charge you for using the GPL-ed code with patents?
Yes they can. Let's say the ACME Software company comes up with a great streaming video codec, they post the specifications online and encourage people to use it. A group of people take those specifications and make programs to make, broadcast and view ACME video, the program gets distributed widely. Two years later we find that prior to publishing the spec, ACME quietly filed for a patent, and it has come through.
My understanding is that ACME would have the legal right (though not the moral right, IMHO) to charge everyone who uses that software, or who has used it in the two year period while the patent is pending, for each time they use the software, or distribute files that were made with that software. This scenario is not that different from what Unisys did with LZW encryption, and GIF files.
Note: I am not a lawyer, none of the above should be construed as legal advice.
----
Open mind, insert foot.