installer uses /dev/dm-* in /etc/crypttab

[GeorgeAllen]

The /dev/dm-* names can get re-numbered when adding/removing changing LVM logical volumes and adding/removing USB drives containing LVM volumes. I performed a fresh install on a new hard drive, connected my old drive via USB, then ran into errors late in a 100G rsync copy. I traced the problem down to: my /dev/dm-* drives had been renumbered, and when cryptswap touched what it thought was the swap volume, it destroyed at data volume instead.

Cryptswap should reference volumes by /dev/disk/by-*/ or /dev/volumegroup/* rather than /dev/dm-*

Steps to recreate: (using Kubuntu 13.04 in a vm)
 - Disk Setup
 - Switch to console.
   sudo -i
   parted
    mktable gpt
    mkpart primary ext4 2048s 200M
    mkpart primary 200M -1s
    toggle 2 lvm
   reboot
   sudo -i
   pvcreate /dev/sda2
   vgcreate vg /dev/sda2
   lvcreate -L 5G -n root vg
   lvcreate -L 2G -n home vg
   lvcreate -L 1G -n swap vg
 - switch to installer
 - Custom Disk setup
   - assign disks as listed:
     vg-home /home
     vg-root /
     vg-swap swap
 - start installer

 - switch to console
    sudo -i
    cat /target/etc/crypttab
    cryptswap1 /dev/dm-2 /dev/urandom swap,cipher=aes-cbc-essiv:sha256

from /var/log/installer/syslog
Apr 30 01:30:35 kubuntu ubiquity: INFO: Setting up swap: [/dev/dm-3]
Apr 30 01:30:35 kubuntu ubiquity: INFO: Successfully setup encrypted swap!

[GeorgeAllen (glallen01)]

Maybe this will help stabilize the device names in /etc/crypttab

--- /tmp/ecryptfs-setup-swap 2013-05-01 21:06:55.750474891 -0400
+++ /usr/bin/ecryptfs-setup-swap 2013-05-01 21:58:43.249884148 -0400
@@ -161,7 +161,7 @@
                [ -e "/dev/mapper/cryptswap$i" ] || break
        done
        # Add crypttab entry
- echo "cryptswap$i $swap /dev/urandom swap,cipher=aes-cbc-essiv:sha256" >> /etc/crypttab
+ echo "cryptswap$i $(findfs UUID=$uuid) /dev/urandom swap,cipher=aes-cbc-essiv:sha256" >> /etc/crypttab

        # Add fstab entry
        echo "/dev/mapper/cryptswap$i none swap sw 0 0" >> /etc/fstab

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "fix-dm-reference.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]