Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

When I installed Ubuntu, I setup an encrypted home partition. Now I have come to an issue where I am running out of memory because I haven't setup swap. How can I setup an encrypted swap file?

A couple of times while booting I've seen some reference to cryptswap. I've also got these lines contained in /etc/fstab

# swap was on /dev/sda6 during installation
#UUID=1ba8a53b-1842-4de7-8e38-2d6c79f3a1ab none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0
share|improve this question
    
In newer ubuntu-versions (tested 14.10). You have to run /etc/init.d/cryptdisks-early reload @Adam Ryczkowski could you post your startup script? –  Jan B Jan 23 at 13:02

1 Answer 1

up vote 13 down vote accepted

Thanks to this guide I have setup an encrypted swap file (can't be used for hiberation).

  1. Firstly create an appropriately sized (I used 8GB) file to store the swap data.

    truncate -s 4GB /cryptswap

  2. Generate the swap using mkswap.

    mkswap /cryptswap

  3. Install a necessary package. apt-get install cryptsetup

  4. Add the following to /etc/fstab

    /dev/mapper/cryptswap none swap sw 0 0

  5. Add the following to /etc/crypttab

    cryptswap /cryptswap /dev/urandom swap

  6. Activate the new encrypted swap file.

    /etc/init.d/cryptdisks reload

    swapon -a

share|improve this answer
    
This encrypted swap is the only secure option for hibernation. With a little change to /etc/crypttab and a startup script (to ask user for mount password) –  Adam Ryczkowski Feb 5 '14 at 15:23
    
@AdamRyczkowski if you're around, another user was asking for that startup script, if you made one. See comment on the question. –  muru Jan 23 at 21:20
    
@muru On Ubuntu 14.04 there is no need for such script. If I recall correctly, the early booting scripts parse the /etc/crypttab for a line like cryptswap /dev/sda5 none luks and asks the user for a password autmatically –  Adam Ryczkowski Jan 24 at 10:39
    
Instead of truncate use fallocate to allocate inode to file; the mkswap step is useless as it is overwritten later when encrypted swap is setup. –  solsTiCe May 28 at 9:49

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.