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

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Message-ID: <20150414065016.GB20597@amd>
Date:	Tue, 14 Apr 2015 08:50:16 +0200
From:	Pavel Machek <pavel@....cz>
To:	Pali Rohár <pali.rohar@...il.com>
Cc:	Mike Snitzer <snitzer@...hat.com>,
	Alasdair Kergon <agk@...hat.com>, Neil Brown <neilb@...e.de>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, dm-devel@...hat.com,
	linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCH 0/3] dm-crypt: Adds support for wiping key when doing
 suspend/hibernation

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 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.

But that might be too hard / impossible. And at that point, I think
Pali's patch is right thing to do.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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