[dm-crypt] Avoiding fsck.ext4 destruction of crypto_luks data

Arno Wagner arno at wagner.name
Sat Dec 29 12:52:22 CET 2012

On Sat, Dec 29, 2012 at 10:05:12AM +0100, Milan Broz wrote:
> On 12/29/2012 08:06 AM, Arno Wagner wrote:
> > On Fri, Dec 28, 2012 at 08:22:25PM +0100, Milan Broz wrote:
> > Ext2 superblock signatures are all not wiped. Test I ran:
> Backup signatures should not be problem, (from the fsck problem
> POV, not from security/old data on disk POV of course).
> Tools screams a lot if you want to use these only and primary
> signature is missing.

Yes, they should. I don't see this as a real problem.
> Anyway, for wiping signature please suggest wipefs(8),
> this tool is designed to wipe all known signatures.

Added. I also give long wipe instructions, but have now
wipefs as fast one.


> (I am trying to avoid linking cryptsetup to libblkid, but
> if this happens some time in future, cryptsetup can call wipefs
> directly.)
>  wipefs -a <device>
> should destroy all known signatures to blkid
> (by minimalistic writes, this is not full device
> wipe, so it is very quick).
> Milan
> _______________________________________________
> dm-crypt mailing list
> dm-crypt at saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt

Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
One of the painful things about our time is that those who feel certainty
are stupid, and those with any imagination and understanding are filled
with doubt and indecision. -- Bertrand Russell

More information about the dm-crypt mailing list