Re: Kernel GPL Violations and How to Research

[Matthew Dharm <mdharm-kernel@one-eyed-alien.net>]

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On Mon, Feb 09, 2004 at 10:53:50PM -0600, Gidon wrote:
> So what I am writing to ask, is what is the best way to ascertain
> whether or not a binary (in this case a "kernel image" of this project)
> contains GPL'd code or functions. So far I have found nearly a hundred
> identical (down to formatting specifiers, punctuation, etc.) or nearly
> identical error messages that consistently match areas of Linux i386
> arch specific kernel code or drivers as well as matching function names,
> using the "strings" program on their Kernel image.

Usually for me, the next step is to disassemble their object code for
symbol information using objdump.

You should be able to get some function names, variable names, etc.  from
that -- if those match the kernel code in question, that's about as good a
"smoking gun" as you can expect to find.  'strings' isn't as good for
function names.

As a final level of analysis, you can always look at the compiled binary
code -- if you think they are using a _reasonably_ compatible compiler, you
might actually be able to find long sections of identical or near-identical
assembly (modulo loop unrolling, etc. which you should be able to identify
by hand.)

Matt

-- 
Matthew Dharm                              Home: mdharm-usb@one-eyed-alien.net 
Maintainer, Linux USB Mass Storage Driver

It's monday.  It must be monday.
					-- Greg
User Friendly, 5/4/1998

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