Re: [PATCH 0/3] dm-crypt: Adds support for wiping key when doing suspend/hibernation

From: Pali RohÃr
Date: Thu Apr 23 2015 - 13:02:22 EST


On Tuesday 14 April 2015 08:50:16 Pavel Machek wrote:
> Hi!
>
> > > > > > So proper way is to wipe luks crypto keys *after* userspace processes
> > > > > > are freezed.
> > > > >
> > > > > I know you believe that I'm just not accepting that at face value.
> > > >
> > > > If disks are synced before any DM suspend operation then we have higher
> > > > chance of preventing data corruption.
> > >
> > > disks are already synced as part of the DM suspend operation!
> > >
> >
> > Yes, but part of hibernate operation is also sync call.
>
> Yes. Maybe that was a mistake.
>

I think not. I do not see any reason why system should not sync disks...

> > > > I still think that correct order is only:
> > > >
> > > > * freeze processes (which doing continous I/O)
> > > > * fs & disk sync
> > > > * DM suspend
> > > > * wipe crypto keys
> > > > * enter hibernate
> > >
> > > I just don't think that extreme is _required_ to have a hibernate/resume
> > > that incorporates dm-crypt key wiping.
> >
> > Ok, and what other developers think?
>
> If someone can fix freezer to work with LUKS stopped, that would be a
> good thing. Can you do it, Mike? Then we can look if it works well
> enough for Pali.
>

Its not only LUKS devices. Its for all dm devices when are suspended.

> But that might be too hard / impossible. And at that point, I think
> Pali's patch is right thing to do.
> Pavel

Yes I think it is hard too...

--
Pali RohÃr
pali.rohar@xxxxxxxxx
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