linux-kernel - Re: [PATCH] MODSIGN: Discard previous signature when signing modules

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Date:	Wed, 27 Mar 2013 00:48:24 +0100
From:	Michal Marek <mmarek@...e.cz>
To:	David Howells <dhowells@...hat.com>
Cc:	Rusty Russell <rusty@...tcorp.com.au>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] MODSIGN: Discard previous signature when signing modules

On 27.3.2013 00:34, David Howells wrote:
> Michal Marek <mmarek@...e.cz> wrote:
> 
>> The format only supports one signature, so discard any previous
>> signature before signing the module.
> 
> That's not totally true.  The format does not preclude multiple signatures.
> You can just add another signature block on the end that signs everything
> inside of that, including all previous signatures.  The alteration to the code
> to check all of them would be very small, I think.

The question is if this would be useful and desired, as opposed to
supporting a list of signatures that all sign the *same* message. My bet
is that such chain of signatures is more likely going to indicate error
than intention. But I don't care much, I haven't run into this myself, I
just thought that others migh do.

Michal
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