Dm-crypt/Mounting at login

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Revision as of 11:10, 11 October 2019 by Bzhb (talk | contribs) (→‎Mounting at login: : add mount command in the script)
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It is possible to configure PAM and systemd to automatically mount a dm-crypt encrypted home partition when its owner logs in, and to unmount it when he logs out.

This tutorial assumes you have already created your encrypted partition, as described in Dm-crypt/Encrypting a non-root file system.

  • You need to use the same password for your user account and for LUKS.
  • In all the examples, replace YOURNAME with your username, 1000 with your user ID and PARTITION with the name of your encrypted partition's device.

Mounting at login

pam_exec can be used to unlock the device at login. Edit /etc/pam.d/system-login and add the line below emphasized in bold after auth include system-auth:

Note: GDM, LightDM, and maybe other display managers might require pam_exec for session as well, see Talk:Dm-crypt/Mounting at login#pam_exec required for session & using script.

auth       include    system-auth
auth       optional expose_authtok /etc/


Then create the mentioned script.



if [ "$PAM_USER" == "$CRYPT_USER" ] && [ ! -e $MAPPER ]
  tr '\0' '\n' | /usr/bin/cryptsetup open /dev/PARTITION home-$CRYPT_USER && mount $MAPPER

Execute chmod +x /etc/ to make it executable.

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Reason: Reconfirmation needed. See Talk. (Discuss in Talk:Dm-crypt/Mounting at login#Suggestion: Remove x-systemd.automount)

Now add your partition to /etc/fstab:


/dev/mapper/home-YOURNAME  /home/YOURNAME     ext4            rw,noatime,noauto 0 2


Your home directory will be mounted automatically on the first access made by your desktop environment or shell.

Unmouting at logout

After you log out of all your sessions, systemd-logind automatically shuts down user@1000.service. Therefore, you can specify that your mountpoint requires it, and systemd will unmount it automatically:


This will however create a circular dependency loop that cannot by resolved automatically by systemd, so you need to describe the dependencies and ordering explicitly:

Note: If your desktop environment or some other application does not kill all its processes on logout, you might need to set KillUserProcesses=yes in /etc/systemd/logind.conf.


After unmounting, the device will still be unlocked, and it will be possible to mount it without re-entering password. You can set up and enable a service that starts when the device gets unlocked (BindsTo=dev-mapper-home\x2dYOURNAME.device) and dies after the device gets unmounted (Requires,Before=home-YOURNAME.mount), locking the device in the process (ExecStop=cryptsetup close):


ExecStop=/usr/bin/cryptsetup close home-YOURNAME

Note: dev-PARTITION is the result of systemd-escape -p /dev/PARTITION