[dm-crypt] yet another "lost my partition" message

Cristian KLEIN cristiklein at gmail.com
Fri Apr 15 15:52:34 CEST 2011

Hello list,

> I've just lost my home partition trying to reinstall ubuntu.
> On the installation process, trying to configure my encrypted home
> partition, I thought it was going to mount my partition but it was asking
> for the new key.
> After that I rebooted and didn't make any other changes to my partition.
> It seems the partitioner used "cryptsetup luksFormat". Do you think I can
> still restore my partition?
> I used the same passphrase configured for my home.

This is *exactly* what I did yesterday. I thought I was tired or
something, but seeing that it happened to somebody else too, I start
thinking that the installer's interface sucks ... badly!

I assume there is no way to recover the original file system. Ubuntu has
most likely overwritten the LUKS header where the pretious salt is being
stored. The unencrypted disk most likely looks like random data now.
According to the FAQ [1], you can still resort to the dm-crypt
mailing-list to get over the five stages of grief.

A posteriori, I cannot help wonder why such pretious information isn't
kept redundantly. Surely LUKS could have stored the header in 10 random
sectors with an easy-to-grep "HERE I AM" banner. Wouldn't this allow
users to recover the master-key (and part of the file-system) without
compromising security?


P.S. Could anybody donate 2^256 CPU-seconds?
P.S.2. What stage of grief am I in? :D

[1] http://code.google.com/p/cryptsetup/wiki/FrequentlyAskedQuestions

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