[SOLVED] How to re-encrypt full disk encryption (Ubuntu)?

quickquestion111 · 04-20-2020, 12:18 PM

Im on a live installation and I sometimes need to unlock the full disk encryption on the underling hard drive. The encryption is the one Ubuntu has you setup during the installation process. Once unlocked from the live environment, I don't know how to lock it again? Help?

dc.901 · 04-20-2020, 12:59 PM

Assuming, you are using cryptsetup, there is option to "close"; from man page:

Quote:

close <name>

Removes the existing mapping <name> and wipes the key from kernel memory.

For backward compatibility there are close command aliases: remove, plainClose, luksClose, loopaesClose, tcryptClose (all behaves exactly the same, device type is determined
automatically from active device).

<options> can be [--deferred]

quickquestion111 · 04-20-2020, 08:51 PM

Quote:

Originally Posted by dc.901

Assuming, you are using cryptsetup, there is option to "close"; from man page:

Hi thanks, but im getting the error 'Device luks-7e3384a1-415c-41bd-bc9e-4a96074238d1 is still in use.' I even un-mounted it from /media, and it still says that.

quickquestion111 · 04-21-2020, 12:02 AM

Apparently that error is not very common, which im suprised as I guess not many people need to close their encrypted hard disks from a live install... I had to deactivate an LVM volume group that existed on the LUKS encrypted partition before closing the crypto-device, before i could run the command

Code:

crypsetup close <mapper-label>

.. Here's the one and only well written article that explained how to do that. https://linux-blog.anracom.com/2018/...s-device-busy/..