GPL-only symbol Error

[Graeme Russ]

Hi Jeff,

On Wed, Nov 23, 2011 at 11:34 AM, Jeff Haran <jharan at bytemobile.com> wrote:
>> -----Original Message-----
>> From: Greg KH [mailto:greg at kroah.com]
>> Sent: Tuesday, November 22, 2011 2:44 PM
>> To: Jeff Haran; Sengottuvelan S; Kernel Newbies
>> Subject: Re: GPL-only symbol Error
>>
>> On Tue, Nov 22, 2011 at 02:35:24PM -0800, Jeff Haran wrote:
>> > I've seen others when faced with this who build their own kernels
> from
>> > sources just modify the problematic EXPORT_SYMBOL_GPL()s to
>> > EXPORT_SYMBOL()s. I don't know if that is legal. I wouldn't do it
>> > personally. Consult a lawyer before you go down that road.
>>
>> It is not legal and companies have gotten into big trouble by trying
> to
>> do that, or by creating "gpl-condom" kernel modules that wrap gpl-only
>> symbols and export them again.  Do not do that without the full buy-in
>> from your legal department as they do not want to hear about it from
> an
>> external query first.
>>
>
> Greg,
>
> Just curious, can you provide links to these cases?
>
> I've read the COPYING file at the top of the Linux source tree. I am not
> a lawyer, but I don't see anything in it that would prohibit somebody
> from taking the GPL kernel sources, changing the EXPORT_SYMBOL_GPL()s to
> EXPORT_SYMBOL()s, publishing that modified kernel source as required by
> the GPL license but then keep their module source that uses the now
> non-GPL symbols private. It seems like it should be prohibited in the
> spirit of open source, but I don't see any mention of these symbol
> declarations in the license.

The mere fact that the "gpl-condom" module links to EXPORT_SYMBOL_GPL
functions make it, in and of itself, a GPL module

ergo, there is no such thing as a "gpl-condom" module

Regards,

Graeme