* Re: GPL issuefor run time kernel function overwrite
2001-07-30 14:48 ` Richard B. Johnson
2001-07-30 15:26 ` Sven Vermeulen
@ 2001-07-31 0:31 ` Rob Landley
1 sibling, 0 replies; 5+ messages in thread
From: Rob Landley @ 2001-07-31 0:31 UTC (permalink / raw)
To: Richard B. Johnson, kumar M; +Cc: linux-kernel
On Monday 30 July 2001 10:48, Richard B. Johnson wrote:
> On Mon, 30 Jul 2001, kumar M wrote:
> > Hi,
> >
> > I have a query regarding the GPL for Linux kernel.
> > We were having a heated discussion regarding
> > opening up / disclosing source code for features
> > added to kernel (as per GPL) if we do the following :
> >
> > * We implement a driver which will overwrite any existing
> > (global kernel data strcuture) function pointer in linux
> > kernel space run-time.
> > * No kernel source code is modified in the process.
You mean like writing to /dev/kmem or some such?
Good luck. Deep, evil black magic. According to Linus you can basically do
anything you want from user space (including loading binary kernel modules at
run-time), but the only way any sort of hook to make intrusive binary-only
changes EASIER is over Linus's dead body. That's my understanding of it,
anyway.
It's going to break going from 2.4.7 to 2.4.8. And then it's going to break
again going from 2.4.8 to 2.4.9. And anybody who has a kernel with your
binary-only gorp in it won't even be LISTENED to if they submit bug reports
to this list with that stuff loaded. They will be sent back to you for all
support including stuff that IS a problem with the rest of the kernel.
> > regards,
> > Kumar
>
> Not only is the wording of GPL, but also its intentions important.
> If the intentions of the GPL are to help promote the free flow
> of ideas, and to show explicitly how some software is implemented,
> then any attempt to obscure, disguise or hide the implementation
> details is contrary to its intent.
>
> It is my opinion that any software that is provided without its
> source-code is contrary to the intent of GPL.
Sure. Including anyone anywhere on the planet to buy or use a copy of
Windows. But intent isn't the only consideration, there ARE the questions of
applicability and standing. :)
> However, I'm sure
> that there are lawyers who will disagree.
Most of them, I suspect.
The intent of the GPL is also bounded by what copyright law will allow (and,
if supplemented by contract law, fun little issues like informed consent and
some formal phrasing of "reasonableness" which I can't remember at the
moment).
You can write a license that says everybody who views your web page owes you
a pint of blood. And although they DID copy your web page (downloading it
and viewing it), it would be just about impossible to enforce in court for a
ton of reasons.
> We already have so-called "proprietary" code being included into
> the kernel. This started with "harmless" bits of binary which is
> uploaded into the hardware when some drivers are installed.
> Including such binary is also contrary to GPL, but without this
> secret goo, the hardware won't run.
Yup. LIke the BIOS calls that boot the sucker up and handle half of APM...
> This exception to GPL, in my opinion, opened the door to future
> corruption and exploitation. Time will tell.
Yeah, so did switching from a "no commercial sales" to the GPL in the first
place. Never play Holier Than Thou with Zeus. (Or Richard Stallman.)
I think the door was open for corruption and exploitation when Linus uploaded
his "term program that grew legs" to the net at large. Once you no longer
personally know all the users...
Linus's weapon against this is frequent, flagrant, severe, and even
gratuitous breakage of intra-kernel binary compatability. You gotta
recompile all your modules with every dot-release. In fact there's the
"include version info" option that make you do that even when nothing really
changed. :)
Anybody who wants to maintain a binary-only module is welcome to try. And is
in for a WORLD of pain. No license by itself will protect code from
exploitation. And neither will wishful thinking about how that license
SHOULD work. An active and informed user community that responds and adapts
to things is what will do it. Only thing that can.
> Now, if your code attacks and destroys, replaces, or otherwise
> modifies a kernel, I think that's fine as long as the source-code
> is provided. You can even develop modules that are designed to
> do harm.
Copyright does not cover use. Copyright has never covered use. It covers
creation and "first sale" disposal of copies. If you own two books, and you
cut and paste the pages together to form a third book, you haven't violated
either copyright. They are your pages, if the use you choose to make of them
involves sticking them in a blender or lining a bird cage with them, that's
your option. Making MORE copies you don't have the legal authority to do,
but manipulating your existing legal copy is your problem.
Computer distribution is slightly different because each time it's
distributed you're making a new copy. (Even if you copy it onto a disk.) So
"first sale" turned into "the license is the entity you own, not any
particular copy of the I.P.", thanks to a certain redmond company lobbying
circa 1980. (Bill Gates did invent ONE thing. Most of the legal backing for
modern proprietary software. He WAS studying to be a lawyer at Harvard
before dropping out...)
But there's still fair use, which got extended to making an archival copy of
things (which you're still allowed to do), and of course space shifting and
time shifting and such...
Creating copies of derived works IS covered by copyright law, and since
that's integral to distribution of computerized gorp, copyright directly
applies (regardless of first sale limits, it seems). Or looked at another
way, the license you own has terms which can make it expire. This has never
quite been upheld in court but has been taken as policy for years and years,
and if it WAS overturned it would probably do a lot MORE damage to
proprietary software companies (out there selling licenses that may not be
worth much, with shrinkwrap clauses limiting the number of "seats" a server
install is good for and such) than to free software. (You'll notice MS is
happy to badmouth the GPL, but isn't going to go near it with lawyers any
time soon.)
Stallman was the first person to figure out that turnabout could be fair
play, and make his own license with terms that followed the software and
dictated terms about its distribution.
So if you make your own program that XORs the kernel image, or compresses it,
your program doesn't have to be GPL. This is fair use, of your own data on
your own hard drive. (And THIS kind of copying has been confirmed fair use a
number of times. Loading a program from disk into ram is not a copyright
violation, it's what the program is FOR.)
And if your program patches the kernel on your hard drive, and your program
contains no GPL itself, the GPL doesn't have any kind of hold over your
program. It hasn't got any leverage to apply copyright law to it.
It's only when you distribute the modified version you get into trouble. If
neither the license nor fair use give you the right to do that, then you're
in for a speeding ticket.
>
> Cheers,
> Dick Johnson
Rob
(P.S. I'm a big fan of the GPL. But trying to stretch it too far, or
claiming it can do things that it can't, only weakens it. Understand your
tools...)
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