Re: [dm-crypt] Broken header of a luks-partition - more than once

From: Arno Wagner <arno@wagner.name>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] Broken header of a luks-partition - more than once
Date: Tue, 25 Aug 2009 05:08:49 +0200	[thread overview]
Message-ID: <20090825030849.GA4485@tansi.org> (raw)
In-Reply-To: <20090824180857.GB31701@tansi.org>

I was too hasty, this should have gone to the list...

On Mon, Aug 24, 2009 at 08:08:57PM +0200, Arno Wagner wrote:
> On Mon, Aug 24, 2009 at 05:55:37PM +0200, Milan Broz wrote:
> > spamzad@googlemail.com wrote:
> > > Something must have overwritten the header (posted it at the bottom) -
> > > and I have no clue what.
> > > That's exactly my question now: might it be a bug in cryptsetup or can
> > > i rule that out?
> > 
> > Cryptsetup never write empty first sectors except explicit LUKS format.
> > (Of course this can very rarely happen if hw/driver problem appears...)
> > 
> > But see crypttab here - you have tmp device created as regular 
> > encrypted device
> > with random key - are you sure that kernel _cannot_ swap sda & sdb and
> > your system just formats temp device here?
> 
> I had that happen to me. Nasty. The BIOS seemd to modify disk order
> when booting from a different drive via the bootup boot device 
> selection.
> 
> One simple way to get around this is to create one-drive RAID1 
> devices and then use them. No moving by the kernel on these.
> 
> Arno
> 
> 
>  
> > > # <target name> <source device>         <key file>      <options>
> > > home            /dev/sdb2               none            luks
> > > ctmp            /dev/sda2               /dev/urandom
> > > tmp,cipher=aes-cbc-essiv:sha256
> > > cswap           /dev/sda5               /dev/urandom
> > > swap,cipher=aes-cbc-essiv:sha256
> > 
> > Milan
> > --
> > mbroz@redhat.com
> > 
> > _______________________________________________
> > dm-crypt mailing list
> > dm-crypt@saout.de
> > http://www.saout.de/mailman/listinfo/dm-crypt
> > 
> 
> -- 
> Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
> GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
> ----
> Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
> 
> If it's in the news, don't worry about it.  The very definition of 
> "news" is "something that hardly ever happens." -- Bruce Schneier 

-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier 