Linux comes with the cryptsetup command. It is used to setup dm-crypt (transparent disk encryption subsystem in Linux kernel) managed device-mapper mappings.

Linux comes with the cryptsetup command. It is used to setup dm-crypt (transparent disk encryption subsystem in Linux kernel) managed device-mapper mappings. This shell script can be used to mount dm-crypt based partitions with passphrase:

  • #!/bin/bash
  • # A simple shell to mount disk encryption based parition under Linux.
  • # Tested on Debian and Ubuntu base NAS servers.
  • # –––––––––––––––––––––––––-
  • # Written by Vivek Gite <http://www.cyberciti.biz/>
  • # (c) 2008 nixCraft under GNU GPL v2.0+
  • # –––––––––––––––––––––––––-
  • # Last updated: 05/Dec/2011
  • # –––––––––––––––––––––––––-
  •  
  • ### commands ###
  • _crypt=„/sbin/cryptsetup”
  • _vg=„/sbin/vgscan”
  • _vgc=„/sbin/vgchange”
  • _mnt=„/bin/mount”
  •  
  • ### SET ME FIRST ###
  • ### Partition specific settings ###
  • ### SET ME FIRST ###
  • _device=„/dev/md3”
  • _name=„securebackup”
  • _mnts=„/dev/cryptvg/mybackup „
  • _mntd=„/securebackup/”
  •  
  • echo
  • ${_crypt} luksOpen ${_device} $_name
  •  
  • echo
  • ${_vg} –mknodes
  • ${_vgc} -ay
  •  
  • echo
  • ${_mnt} ${_mnts} ${_mntd}
 

This script is stored on our nas server. All backups are on RAID-6 disks are encrypted. The nas server is online 24×7. After rebooting the server you need to run this script to mount the dm-crypt based partition. A sample session is as follows:

$ ssh vivek@nas112.backup.lan.nixcraft.co.in
$ sudo /usr/local/sbin/mount.crypt

Sample outputs:

 Enter passphrase for /dev/md3:   Reading all physical volumes.  This may take a while...   Found volume group "cryptvg" using metadata type lvm2   1 logical volume(s) in volume group "cryptvg" now active

Verify disk space and newly mounted partition:

$ df -H

Sample outputs:

 Filesystem             Size   Used  Avail Use% Mounted on /dev/md0               127G   930M   120G   1% / tmpfs                  1.1G      0   1.1G   0% /lib/init/rw udev                   1.1G   267k   1.1G   1% /dev tmpfs                  1.1G      0   1.1G   0% /dev/shm /dev/md2               1.6T    88G   1.5T   6% /data /dev/mapper/cryptvg-mybackup                        635G    59G   544G  10% /securebackup

 

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