Seems GPL2 or GPL3 already requires this [LWN.net]

Seems GPL2 or GPL3 already requires this

Posted Nov 28, 2024 8:21 UTC (Thu) by anselm (subscriber, #2796)
In reply to: Seems GPL2 or GPL3 already requires this by malmedal
Parent article: Arch Linux finally starts licensing PKGBUILDs

According to Bradley Kuhn, this is not correct, he says you could install and run your own Linux-version on TiVo as much as you wanted

I wasn't making a claim about the TiVo in particular – this was just a hypothetical to describe the sort of provisions the GPLv3 adds to prevent clever antics on the part of device makers.

(You could note, too, that Linux specifically is GPLv2, so nothing in the GPLv3 that isn't in the GPLv2 would apply to a Linux-based DVR in any case. Just imagine, for the sake of the discussion, a future Linux-like operating system that DVR manufacturers might like to use and that is published under the GPLv3.)

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Seems GPL2 or GPL3 already requires this

Posted Nov 28, 2024 11:34 UTC (Thu) by malmedal (subscriber, #56172) [Link] (7 responses)

> I wasn't making a claim about the TiVo in particular

Sure, Kuhn's claim is that TiVo agreed that GPLv2 forced them to allow the user to install and run modified Linux.

I believe this sentence from your post is wrong:

>>> but its proprietary boot loader will only run an operating system signed with the device maker's private key, which is not part of your software package.

If I am understanding Kuhn correctly he says that GPLv2 already forces the device manufacturer to provide such keys, and that TiVo agreed and complied in the case of their device.

Seems GPL2 or GPL3 already requires this

Posted Nov 28, 2024 13:35 UTC (Thu) by anselm (subscriber, #2796) [Link] (6 responses)

If I am understanding Kuhn correctly he says that GPLv2 already forces the device manufacturer to provide such keys, and that TiVo agreed and complied in the case of their device.

I'm certainly not going to disagree about GPL interpretation with Bradley Kuhn, who is after all a lawyer and noted GPL expert.

It does leave me wondering, though, why the GPLv3 went to the trouble of adding all sorts of provisions about “User Products” and so on, if the GPLv2 already does what is required. (In the case of the TiVo there's obviously no way the Linux kernel license could prevent the – “merely aggregated” – TiVo user-space software from checking whether it is running on an official TiVo-provided kernel and refusing to work if it isn't, and that would presumably also apply if the kernel was GPLv3 instead of GPLv2.)

Seems GPL2 or GPL3 already requires this

Posted Nov 28, 2024 16:27 UTC (Thu) by malmedal (subscriber, #56172) [Link] (3 responses)

I believe it is because of this paragraph in GPLv3(important bit in bold):

"Installation Information" for a User Product means any methods, procedures, authorization keys, or other information required to install and execute modified versions of a covered work in that User Product from a modified version of its Corresponding Source. The information must suffice to ensure that the continued functioning of the modified object code is in no case prevented or interfered with solely because modification has been made.

Kuhn says he asked Stallman and Stallman confirmed that the point of this was to ensure that proprietary software should continue to function normally even if the GPL parts were modified, and my understanding is that this also holds for "mere aggregation".

Seems GPL2 or GPL3 already requires this

Posted Nov 29, 2024 1:55 UTC (Fri) by pabs (subscriber, #43278) [Link] (2 responses)

That sentence only seems to cover the modified GPLed code though? IIRC from Kuhn's posts, in the TiVo scenario the modified GPLed code still works fine, its just that the proprietary userland code running on it will not.

Seems GPL2 or GPL3 already requires this

Posted Nov 29, 2024 1:57 UTC (Fri) by pabs (subscriber, #43278) [Link] (1 responses)

See also Kuhn's GPLv3 in automotive presentation:

https://events19.linuxfoundation.org/wp-content/uploads/2...

Seems GPL2 or GPL3 already requires this

Posted Nov 29, 2024 10:41 UTC (Fri) by malmedal (subscriber, #56172) [Link]

Interesting, thank you, in his blog-post Kuhn writes.

Specifically, I asked him on 2012-05-05:
[so], these words in GPLv3: “The information must suffice to ensure that the continued functioning of the modified object code is in no case prevented or interfered with solely because modification has been made.” mean that the proprietary software that is not a combined work with the GPLv3'd work must also function?
Stallman replied on 2012-05-06 with:
Absolutely. And I wrote it specifically to do that!

In the slides he says:

Ironically, even if Linux were GPLv3, Tivo’s method of crypto-lock-down would likely comply with GPLv3.

bkuhn checked this with RMS: even he agrees this mechanism complies with GPLv3.

I can't find anywhere he has written his reasoning, would be interested to read a longer explanation of exactly what would and would not be a violation.

Seems GPL2 or GPL3 already requires this

Posted Nov 29, 2024 13:24 UTC (Fri) by paulj (subscriber, #341) [Link]

Last I knew, bkuhn did not claim to have any formal legal qualifications. Even if he were, you certainly could still disagree with Bradley - because there is no consensus in the legal world on a number of questions around the GPL.

Sometimes I get the feeling that some of the leading copyleft lawyers almost prefer not to see these questions argued in court and decided authoritatively (and here I do not refer in any way to bkuhn or anyone related to SFC, just for clarity). But maybe that's just my limited experience.

Seems GPL2 or GPL3 already requires this

Posted Nov 29, 2024 15:42 UTC (Fri) by Wol (subscriber, #4433) [Link]

> It does leave me wondering, though, why the GPLv3 went to the trouble of adding all sorts of provisions about “User Products” and so on, if the GPLv2 already does what is required.

Maybe, at the time, it didn't?

Especially in light of the Playstation II furore, maybe TiVo changed the mechanism to be GPL3-compatible. If I thought something at work was a grey area (legal, H&S, whatever) and I could see a quick fix, I'd push for it ...

Businesses don't like expensive problems. Offer them a quick and cheap fix for a potentially expensive problem, and you should be able to get it through.

Cheers,
Wol