Linus on DRM

Linus Torvalds weighed in on the DRM debate on the linux-kernel mailing list last night. No, don't click through, his email is reproduced below. Worth reading and thinking about.

Thread on LKML:

Date: Wed, 23 Apr 2003 20:59:45 -0700 (PDT)
From: Linus Torvalds
To: Kernel Mailing List
Subject: Flame Linus to a crisp!

Ok,
there's no way to do this gracefully, so I won't even try. I'm going to
just hunker down for some really impressive extended flaming, and my
asbestos underwear is firmly in place, and extremely uncomfortable.

I want to make it clear that DRM is perfectly ok with Linux!

There, I've said it. I'm out of the closet. So bring it on...

I've had some private discussions with various people about this already,
and I do realize that a lot of people want to use the kernel in some way
to just make DRM go away, at least as far as Linux is concerned. Either by
some policy decision or by extending the GPL to just not allow it.

In some ways the discussion was very similar to some of the software
patent related GPL-NG discussions from a year or so ago: "we don't like
it, and we should change the license to make it not work somehow".

And like the software patent issue, I also don't necessarily like DRM
myself, but I still ended up feeling the same: I'm an "Oppenheimer", and I
refuse to play politics with Linux, and I think you can use Linux for
whatever you want to - which very much includes things I don't necessarily
personally approve of.

The GPL requires you to give out sources to the kernel, but it doesn't
limit what you can _do_ with the kernel. On the whole, this is just
another example of why rms calls me "just an engineer" and thinks I have
no ideals.

[ Personally, I see it as a virtue - trying to make the world a slightly
better place _without_ trying to impose your moral values on other
people. You do whatever the h*ll rings your bell, I'm just an engineer
who wants to make the best OS possible. ]

In short, it's perfectly ok to sign a kernel image - I do it myself
indirectly every day through the kernel.org, as kernel.org will sign the
tar-balls I upload to make sure people can at least verify that they came
that way. Doing the same thing on the binary is no different: signing a
binary is a perfectly fine way to show the world that you're the one
behind it, and that _you_ trust it.

And since I can imaging signing binaries myself, I don't feel that I can
disallow anybody else doing so.

Another part of the DRM discussion is the fact that signing is only the
first step: _acting_ on the fact whether a binary is signed or not (by
refusing to load it, for example, or by refusing to give it a secret key)
is required too.

But since the signature is pointless unless you _use_ it for something,
and since the decision how to use the signature is clearly outside of the
scope of the kernel itself (and thus not a "derived work" or anything like
that), I have to convince myself that not only is it clearly ok to act on
the knowledge of whather the kernel is signed or not, it's also outside of
the scope of what the GPL talks about, and thus irrelevant to the license.

That's the short and sweet of it. I wanted to bring this out in the open,
because I know there are people who think that signed binaries are an act
of "subversion" (or "perversion") of the GPL, and I wanted to make sure
that people don't live under mis-apprehension that it can't be done.

I think there are many quite valid reasons to sign (and verify) your
kernel images, and while some of the uses of signing are odious, I don't
see any sane way to distinguish between "good" signers and "bad" signers.

Comments? I'd love to get some real discussion about this, but in the end
I'm personally convinced that we have to allow it.

Btw, one thing that is clearly _not_ allowed by the GPL is hiding private
keys in the binary. You can sign the binary that is a result of the build
process, but you can _not_ make a binary that is aware of certain keys
without making those keys public - because those keys will obviously have
been part of the kernel build itself.

So don't get these two things confused - one is an external key that is
applied _to_ the kernel (ok, and outside the license), and the other one
is embedding a key _into_ the kernel (still ok, but the GPL requires that
such a key has to be made available as "source" to the kernel).

Linus

Comments

What this is about

[amcguinn]

No-one commenting so far seems to have a clue what this is all about, so here goes.

Imagine someone builds hardware that will only run binaries signed by the manufacturer (current example: X-box, future examples: who knows)

Now imagine someone makes a version of Linux with functionality limited in some way -- think DRM, and gets that version signed by the hardware manufacturer so that it will run on the controlled hardware.

Now, as a user of that version of Linux, you have all your GPL rights to obtain, modify, and redistribute the source. But, since only the exact original signed binary will actually run on the hardware, those rights are (arguably) worthless.

Linus is saying that this is permissible, or at least that it is not his job to try to prevent it.

Now at least the flames can be on-topic...

Re:terrorist

[ReelOddeeo]

Can you name one person who is actually on record arguing that open source software should not be permitted to exist?

They are not on record. And I won't actually name one of my co-workers. But Yes.

There are others who have been far more public however. There was one Jim Allchin a couple years ago. He didn't come right out and say it, but he dances around it and implies it quite well.

From a cnet article here.

Microsoft Corp.'s Windows operating-system chief, Jim Allchin, says that freely distributed software code such as rival Linux could stifle innovation and that legislators need to understand the threat.

....

That, as well as programs such as music-sharing software from Napster Inc., means the world's largest software maker has to do a better job of talking to policymakers, he said.

....

''Open source is an intellectual-property destroyer,'' Allchin said. ''I can't imagine something that could be worse than this for the software business and the intellectual-property business.''

....

''I'm an American, I believe in the American Way,'' he said. ''I worry if the government encourages open source, and I don't think we've done enough education of policy makers to understand the threat.''