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Chapter 10.4 - Using and encrypted partition

kolyan007kolyan007 Posts: 4
edited March 2017 in LFS201 Class Forum

My test environment is not VLM. How to create encrypted partition (Ubuntu 14)?

I've created folder /dev/VG/MYSECRET

Command below is not prompting for a passphrase.

#cryptsetup luksFormat /dev/VG/MYSECRET/

WARNING!

========

This will overwrite data on /dev/VG/MYSECRET/ irrevocably.

Are you sure? (Type uppercase yes): yes

 

Thanks for advice,

Nick

Comments

  • sadamahansadamahan Posts: 11

    Hello Nick

    You don't create the folder: /dev/VG/MYSECRET

    Instead, you start by creating a LUKS container. The container gets created on top of storage device (/dev/sda3 in the example below) or a logical volume (like /dev/mapper/lvname). Say, I had a storage device /dev/sda3, I would: 

    cryptsetup luksFormat /dev/sda3

    luksFormat is followed by luksOpen which creates a luks container for the formatted storage or logical volume: cryptsetup –verbose luksOpen  /dev/sda3 c1

    luksOpen above creates a device called /dev/mapper/c1 from /dev/sda3

    You would then format:  mkfs -t ext4 /dev/mapper/c1  and use!

    Best Regards

    SMK

  • Hi SMK,

    Thanks for your reply. I've mounted partition image file as /dev/loop3 and tried to create luks container. See the output below:

    # df -H

    Filesystem      Size  Used Avail Use% Mounted on

    udev            2.0G  8.2k  2.0G   1% /dev

    tmpfs           402M  1.1M  401M   1% /run

    /dev/sda1        19G  7.1G   11G  40% /

    none            4.1k     0  4.1k   0% /sys/fs/cgroup

    none            5.3M     0  5.3M   0% /run/lock

    none            2.1G  148k  2.1G   1% /run/shm

    none            105M   29k  105M   1% /run/user

    /dev/loop3      1.1G  1.4M  952M   1% /mnt/mntpoint

    # cryptsetup luksFormat /dev/loop3

    WARNING!

    ========

    This will overwrite data on /dev/loop3 irrevocably.

    Are you sure? (Type uppercase yes): yes

    # cryptsetup --verbose luksOpen /dev/loop3 c1

    Device /dev/loop3 is not a valid LUKS device.

    Command failed with code 22: Device /dev/loop3 is not a valid LUKS device.

    Why loop3 still not a valid LUKS device?

  • Hi Nick,

    As pointed above, /dev/VG/MYSECRET is not a folder, it's a device (a LVM in this case). You also can work with any other non LVM partition. I recommend first to use a normal partition instead a loop device, so you can get some practice and then try with a loop device.

    Regards,

    Luis.

  • kolyan007kolyan007 Posts: 4
    edited March 2017

    I've mounted normal partition as /dev/sdb1, but still not sure how to encrypt it.

    /dev/sdb1       1.1G  1.4M  968M   1% /home/student/mydata

    Please advise.

    Nick

  • luisviveropenaluisviveropena Posts: 365
    edited March 2017

    Hi Nick,

    1) Unmount the partition.

    2) Then do the following:

    $ sudo cryptsetup luksFormat /dev/sdb1

    $ sudo cryptsetup luksOpen /dev/sdb1 secret-disk

    Then keep following the instructions of the lab.

    Regards,

    Luis.

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