From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Oliver Neukum <oliver@neukum.org>
Subject: Re: [PATCH] zero disk pages used by swsusp on resume
Date: Mon, 11 Apr 2005 18:39:50 +0200
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Cc: Pavel Machek <pavel@ucw.cz>, Andreas Steinmetz <ast@domdv.de>,
       Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>
References: <42592697.8060909@domdv.de> <20050410201455.GA21568@elf.ucw.cz> <200504111237.45452.oliver@neukum.org>
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Hi,

On Monday, 11 of April 2005 12:37, Oliver Neukum wrote:
> Am Sonntag, 10. April 2005 22:14 schrieb Pavel Machek:
> > Hi!
> > 
> > > > Oliver Neukum wrote:
> > > > > What is the point in doing so after they've rested on the disk for ages?
> > > > 
> > > > The point is not physical access to the disk but data gathering after
> > > > resume or reboot.
> > > 
> > > After resume or reboot normal access control mechanisms will work
> > > again. Those who can read a swap partition under normal circumstances
> > > can also read /dev/kmem. It seems to me like you are putting an extra
> > > lock on a window on the third floor while leaving the front door open.
> > 
> > Andreas is right, his patches are needed.
> > 
> > Currently, if your laptop is stolen after resume, they can still data
> > in swsusp image.
> > 
> > Zeroing the swsusp pages helps a lot here, because at least they are
> > not getting swsusp image data without heavy tools. [Or think root
> > compromise month after you used swsusp.]
> > 
> > Encrypting swsusp image is of course even better, because you don't
> > have to write large ammounts of zeros to your disks during resume ;-).
> 
> Not only is it better, it completely supercedes wiping the image.
> Your laptop being stolen after resume is very much a corner case.
> You suspend your laptop while you are not around, don't you?

Not necessarily.  Some people use suspend instead of shutdown. :-)

Greets,
Rafael


-- 
- Would you tell me, please, which way I ought to go from here?
- That depends a good deal on where you want to get to.
		-- Lewis Carroll "Alice's Adventures in Wonderland"
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