25 Aug 2014

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How to Enable an Encrypted Swap Partition

Tags: Ubuntu 14.04

I came up with this solution when ecryptfs-setup-swap failed to work on my system, possibly because I have a GUID Partition Table on my disk. So I used the Ubuntu Disks GUI utility to format my swap partition as LUKS+ext4 and then put together this script to enable it on log-in.

/etc/profile.d/encrypted-swap.sh

System specific parameters

PARTITION_RAW="/dev/sda10"
PARTITION_UNLOCKED="/dev/mapper/luks-5edddf9e-76b9-4030-9fd3-90502211ace3"

The code

First, make sure the swap partition isn’t already unlocked.

if [[ -z `ls $PARTITION_UNLOCKED` ]];
then
  echo "Unlocking encrypted swap partition..."  
  udisksctl unlock -b $PARTITION_RAW
fi

Make sure it’s not already enabled as a swap device.

if [[ -z `swapon -s | grep $PARTITION_UNLOCKED` ]]
then
  echo "Enabling swap..."
  sudo swapon $PARTITION_UNLOCKED
fi

To ensure this works for GUI sessions run this script as a “Start-up Application” using the GUI tool for such, or by manually adding a .desktop file to ~/.config/autostart to run this script, e.g.,

gnome-terminal -e "/etc/profile.d/encrypted-swap.sh"

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