[dm-crypt] Where is the entered password stored?

Arno Wagner arno at wagner.name
Mon Dec 8 13:45:29 CET 2014


this is really not something cryptsetup does. There is some
application or script that your distribution uses to 
implement this functionality, so you have to look there.

Cryptsetup stores the master-key in kernel-memory while the 
LUKS container is mapped (open) and wipes it from memory on 
luksClose. Cryptsetup never stores the passphrase.

You can get the master-key from a mapped device from the
kernel (as root), though. FAQ Item 6.10 explains how.


On Mon, Dec 08, 2014 at 13:06:14 CET, Jian-Ming Zheng wrote:
> Hi,
> When I attach a hard disk with LUKS encrypted partition to a Linux
> machine, a window will pop up and a password or passphrase is required
> to unlock the encrypted partition. In addition to forget passphrase
> immediately, I can choose to 1) remember passphrase until I logout or
> 2) remember forever. I am curious about where the entered passphrase
> is kept in the two cases?
> Thanks.
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Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
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