cryptsetup versions: cryptsetup 2.3.4 vs. cryptsetup 2.1.0 - thought I had data corruption!?!

Hi all,

I've been cryptsetup and LUKS-encryption a lot in the past 5 years and the
only time I've really lost data is because I locked myself out of my linux
boot-partition during a kernel upgrade/initramfs-generation (still not sure
what happened, but I've learned now that I should ALWAYS have a backup
password instead of relying on a key which I lost). But the last 3-4 days
scared the shit out of me, as I took a complete backup of maybe 15 years of
data (5-6 TB), verified with md5sum that the copy also was ok - but in
order to have space for that (~5-6 TB) I deleted my previous unencrypted
backup, otherwise I had to buy a new disk and I trusted things were ok...
When I saw the md5sum on the backup disk was ok, I felt "safe" and wanted
to unlock my partition (just after deleting the unencrypted data, to have
space). I used cryptsetup on a Debian (proxmox)-installation where the
encrypted data was also stored and it worked before doing the backup. But
after making the backup I got something like:

*"mount: wrong fs type, bad option, bad superblock on /dev/mapper/....,
missing codepage or helper program, or other error*

At first I thought it was simple: I googled and found out I should use
e2fsck with an option to use another superblock. I read I should try the
first, reboot, then the next, reboot, etc - until I've went through them
all or until it works.... It didn't work - I was shocked, I thought I had
made the mistake of my life and lost all my data...

Nothing on google pointed me to the solution - I was screwed - I thought. I
think the problem happened because I was primarily using Debian / proxmox
(where the encrypted data is) with cryptsetup 2.1.0. But it might have
happened that just before doing the backup, I had "sshfs'ed" to my laptop
with Arch Linux, which is using cryptsetup 2.3.4. I think after opening the
LUKS-container with cryptsetup 2.3.4 (and closing it again after use, hence
probably forcing some things to be written), the encrypted data couldn't -
and cannot be opened with cryptsetup 2.1.0 anymore... At least this was/is
the solution for me: Don't use debian/proxmox with cryptsetup 2.1.0
anymore, instead use Arch Linux with version 2.3.4... I'm still terrified -
but tried to investigate the difference with luksDump (encrypted file). It
says LUKS is version 2, epoch 3, pbkdf2 is used, aes-xts-plain64 cipher
with 512 bits key - and everything is completely the same using both
luksDump-versions...

I tried to look in version history but am not into the details of the
difference in crypt-setup versions. Can anyone please tell why I got/get
this error using 2.1.0 and not with 2.3.4?

"mount: wrong fs type, bad option, bad superblock on /dev/mapper/....,
missing codepage or helper program, or other error

Questions that popup are:  Is there a fix? Is it recommended to stick with
2.3.4? Should I worry in the future?

I would be grateful to understand this better, to not screw up in the
future. Furthermore, I think or hope this could/can maybe help others, as I
didn't found this solution on google or any other place. I almost gave up
all hope and was prepared to delete the LUKS-container, before I thought I
would try this "long shot" - phew, I'm just happy I have my data back.
Please elaborate or explain the version difference together with your
comments, I would be very grateful for that, thanks!


Br,
M.

_______________________________________________
dm-crypt mailing list
[email protected]
https://www.saout.de/mailman/listinfo/dm-crypt