Re: [dm-crypt] Restore a LUKS partition

[Arno Wagner <arno@wagner.name>]

On Thu, Nov 21, 2013 at 02:25:16 CET, Michael Grosseck wrote:
> Hello,
> 
> I created a luks partition for a long time with Ubuntu 10.04. Most
> likely I used following command to create it.
> 
> # cryptsetup -c blowfish-cbc-essiv:sha256 -y -s 256 luksFormat /dev/sda6
> 
> In the meantime I changed the distro to Linux Mint 13.
> Now I tried to open it, but I get an error. Also if I try to dump
> the header information.
> 
> $ sudo cryptsetup luksDump -vc blowfish-cbc-essiv:sha256 /dev/sda6
> Device /dev/sda6 is not a valid LUKS device.
> Command failed with code 22: Device /dev/sda6 is not a valid LUKS device.

Use cryptsetup -v isLuks to find whether it is a LUKS container,
no other parameters.

> I was not sure if the drive is a LUKS device at all and I have read
> in another forum I should search for LUKS, what I did.
> 
> $ sudo dd if=/dev/sda6 | grep -a -b LUKS
> 0:�������?\x111�U�LUKS��\x01blowfishcbc-essiv:sha256sh
> E���\x17���֬�y[8�@��/�\x06ā\x04�]1b(�?K \x1c�uP�Xb6'\x18��C��
> 362478668:rC�+9���\\x01D�#�8*\x12tfoye�/�34ڛ�OCI\x1f[��\x19�5���E\x15!U�3_B\x02��%�\x11rLUKS�\x01$i}�H�[g>�rw̋��G�O
> �����6��>�b�\x02�s��e$�tɞV

That is not the way to search. Better post what
  hd /dev/sda6 | head 
gives you. 
 
> So indeed it seems a LUKS device, but the header is somehow corrupt.
> 
> Now I tried to make a plain mapping what unexpected really works.
> But the joy was short. I can not mount the mapped device.

You can always create a plain mapping, there is no error checking
as a plain device has no header.

> $ sudo cryptsetup create -c blowfish-cbc-essiv:sha256 -s 256 crypt /dev/sda6
> Enter passphrase:
> $ sudo mount /dev/mapper/crypt /home/crypt/
> mount: you must specify the filesystem type
> $ sudo mount -t ext3 /dev/mapper/crypt /home/crypt/
> mount: wrong fs type, bad option, bad superblock on /dev/mapper/crypt,
> missing codepage or helper program, or other error
> In some cases useful info is found in syslog - try
> dmesg | tail or so
> 
> Now my question. Is there a little hope to restore the LUKS header
> or at least to read the content of this partition somehow?

Completely unclear at this time. 
 
Arno

> Thanks for your help
> 
> Michael
> 
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-- 
Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno@wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
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so simple that there are obviously no deficiencies, and the other way is to
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