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

[spamzad@googlemail.com]

Hello there,


Some weeks ago, my luks-partition (/dev/sdb2) broke - it was supposed to
be /dev/mapper/home and then /home. Cryptsetup didn't recognize it as a
luks-partition. So i tried to get my data back and failed. Then I set
up the whole thing again - which worked for several days (and reboots),
but finally the same thing happened again - I didn't really know what
to do, so I tried to check my harddisk with a Samsung tool (it's a
spinpoint f1), but that didn't work either. So I replaced the harddisk.
That made it work again for another couple of days until it broke again.
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?
I also saved my /etc/fstab and /etc/crypttab, because they were fine -
however, I'll show you all of it:


fstab:

martin@Computername:~$ cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'vol_id --uuid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name
devices # that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sdb1 during installation
UUID=26aaffd8-b550-4cd7-a85d-3d906f31f396 /               ext3
relatime,errors=remount-ro 0       1 # swap was on /dev/sda5 during
installation # UUID=ec514d0c-11e7-4c6d-ae99-99150ca52f86
none            swap    sw              0
0 /dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec,utf8
0       0 #cryptsetup-zeugs /dev/mapper/home        /home   ext3
defaults  0     2 /dev/mapper/ctmp        /tmp    ext2    defaults
0     0 /dev/mapper/cswap       swap    swap    swap    0       0


crypttab:

martin@Computername:~$ cat /etc/crypttab
# <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



headers:

martin@Computername:~$ sudo xxd /dev/sdb2 | head
[sudo] password for martin:
0000000: 4c55 4b53 babe 0001 6165 7300 0000 0000  LUKS....aes.....
0000010: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000020: 0000 0000 0000 0000 7874 732d 706c 6169  ........xts-plai
0000030: 6e00 0000 0000 0000 0000 0000 0000 0000  n...............
0000040: 0000 0000 0000 0000 7368 6131 0000 0000  ........sha1....
0000050: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000060: 0000 0000 0000 0000 0000 0fc8 0000 0040  ...............@
0000070: 3937 0359 0b40 0608 497a 9995 6734 da4d  97.Y.@..Iz..g4.M
0000080: 6813 8d2e f151 f2df 4f43 9454 5fa8 2d23  h....Q..OC.T_.-#
0000090: 50b5 37f1 46dd 5bc4 aecd 88ea f967 5a51  P.7.F.[......gZQ

A comment about the above one: I think that already is not what it's
supposed to be - but I'm not sure. However at the moment it works -
because i set it up again. When it was broke, you couldn't read
anything, but data-trash - so there was no LUKS, aes or xts-plain to be
read in plain text. It looked more like the last 3 lines.





martin@Computername:~$ sudo xxd /dev/sdb1 | head
0000000: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000010: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000020: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000030: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000040: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000050: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000060: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000070: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000080: 0000 0000 0000 0000 0000 0000 0000 0000  ................
0000090: 0000 0000 0000 0000 0000 0000 0000 0000  ................





0000000: eb48 9010 8ed0 bc00 b0b8 0000 8ed8 8ec0  .H..............
0000010: fbbe 007c bf00 06b9 0002 f3a4 ea21 0600  ...|.........!..
0000020: 00be be07 3804 750b 83c6 1081 fefe 0775  ....8.u........u
0000030: f3eb 16b4 02b0 01bb 007c b280 8a74 0302  .........|...t..
0000040: ff00 0020 0100 0000 0002 fa90 90f6 c280  ... ............
0000050: 7502 b280 ea59 7c00 0031 c08e d88e d0bc  u....Y|..1......
0000060: 0020 fba0 407c 3cff 7402 88c2 52be 7f7d  . ..@|<.t...R..}
0000070: e834 01f6 c280 7454 b441 bbaa 55cd 135a  .4....tT.A..U..Z
0000080: 5272 4981 fb55 aa75 43a0 417c 84c0 7505  RrI..U.uC.A|..u.
0000090: 83e1 0174 3766 8b4c 10be 057c c644 ff01  ...t7f.L...|.D..


no clue if that's okay..




Thanks in advance


Martin :)