Re: [dm-crypt] miscellaneous dm-crypt/LUKS/cryptsetup questions

[Arno Wagner <arno@wagner.name>]

On Thu, May 27, 2010 at 08:21:11PM +0200, Milan Broz wrote:
> On 05/27/2010 06:21 PM, Mario 'BitKoenig' Holbe wrote:
> > Milan Broz <mbroz@redhat.com> wrote:
> >> (read from /dev/random can return if there is not enough entropy, it needs
> > 
> > Nope. It blocks.
> 
> yep, you are right :)
> 
> The problem is that can wait very long time, so it should inform user that
> system is out of entropy and ask for some action etc. This should be part
> of the RNG handler in cryptsetup if using /dev/random is supported.

Indeed. You could also just flush an explanation to stdout and ask
the user to provide keystrokes if things take long. That would 
remove the need for monitoring what comes from /dev/random.
Maybe use this as a temporary fix that amounts to one printf.

However that does not solve the case of automatic installation
on, e.g., embedded devices that have a low-entropy envoronment.

Arno
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
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