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

Milan Broz gmazyland at gmail.com
Fri Dec 28 20:22:25 CET 2012


On 12/28/2012 04:04 PM, Arno Wagner wrote:
> I am thinking about a "basic LUKS setup" section for the FAQ 
> that is more in the nature of a mini-howto. Things like blanking
> a previously used partition before a LUKS install seem to be 
> not obvious to many people. Step-by-step instructions may help.

Wiping (whole) device (with some crypt random way) is still on TODO list.

But I believe that common signatures are wiped during LUKS format already
(we had several bugs related to this already) so it should never
happen that device contains ext4/swap/whatever signature parallel with
LUKS. (If so, please let me know, it is a bug.)

fsck can possibly use blkid and warn user
"Warning: device seems to contain xyz signature, do you really want...."
but this is feature for fsck (util-linux), not for cryptsetup.
(Anyway, I can ask util-linux maintainer later next year:)

Milan


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