[dm-crypt] Help needed please with luks volume

Milan Broz mbroz at redhat.com
Sun Apr 1 21:34:21 CEST 2012

On 04/01/2012 09:09 PM, Bhasker C V wrote:
> Hi all
>  Sorry for the cross-list posting; I think this will help.
>   I have a luks formatted volume and on debian this volume just stopped
> working after a  dist-upgrade
>  The error reported is as below
> $ sudo cryptsetup luksOpen /dev/sdc dsk
> LUKS keyslot 6 is invalid.
> LUKS keyslot 7 is invalid.
> $ cryptsetup --version
> cryptsetup 1.4.1
> $ uname -a
> Linux bcv 3.2.9 #1 SMP Sat Mar 10 20:36:56 GMT 2012 x86_64 GNU/Linux
> Whereas when used in an older version (in my office) this disk works
> perfectly fine and I am able to view data.


see http://code.google.com/p/cryptsetup/wiki/FrequentlyAskedQuestions#4._Troubleshooting
and http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=662768#10

I think it is exactly your problem, your LUKS header is corrupted
by written partition table signature - but it can be fixed.

If you want, send me (in private mail) the first 4k of your LUKS
device (IOW the visible part, no keyslot data) and I can fix that.

IOW output of "dd if=/dev/<your luks device> of=bck.img bs=1k count=4

> Can someone help please ? Or is this a bug introduced in the newer
> versions ?

See my comment on the bug - it is additional safety check, using
corrupted header can cause data corruption later.

(If there are more cases, I'll enable repair code by default but it
seems this problem is very rare. It is not bug in cryptsetup, just
previous version ignored unsafe keyslot offsets.)


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