[Bug 1837437] Re: disk content permanently lost when changing LUKS password

[Mathew Hodson]

** Package changed: gnome-disk-utility (Debian) => libblockdev (Debian)

** Changed in: libblockdev (Ubuntu)
   Importance: Undecided => High

** Changed in: libblockdev (Ubuntu Disco)
   Importance: Undecided => High

-- 
You received this bug notification because you are a member of Ubuntu
Sponsors Team, which is subscribed to the bug report.
https://bugs.launchpad.net/bugs/1837437

Title:
  disk content permanently lost when changing LUKS password

Status in libblockdev package in Ubuntu:
  Fix Released
Status in libblockdev source package in Disco:
  Confirmed
Status in libblockdev package in Debian:
  Unknown

Bug description:
  [Impact]

  Users with full disk encryption trying to change the encryption
  passphrase in gnome-disks will get an error message, and after
  rebooting neither the old passphrase nor the new one can unlock their
  disk, rendering the machine unusable.

  
  [Test Case]

  (can be done in a virtual machine, for testing purposes)
  1. Download a 19.04 ISO, and install it, choosing the full disk encryption option
  2. When rebooting after the installation is complete, you are prompted for your passphrase to unlock the disk
  3. Once logged in, open gnome-disks, select the encrypted disk and click the contextual action to change the encryption passphrase
  4. Enter your old passphrase and the new one (twice), as prompted, then click OK

  Expected result: the passphrase is changed successfully, and when
  rebooting the new passphrase can unlock the disk

  Current result: changing the passphrase fails, the user is presented
  with an error message ("Error changing passphrase on device /dev/sda5:
  Failed to add the new passphrase: Invalid argument (udisks-error-
  quark, 0)"), and when rebooting neither the old passphrase nor the new
  one can unlock the disk, which renders it unusable

  To test the fix, the updated libblockdev* packages need to be
  installed on the machine before attempting to change the encryption
  passphrase in gnome-disks.

  
  [Regression Potential]

  The patch only touches code related to changing the LUKS encryption passphrase, so non-encrypted disk setups should not be affected.
  Scenarii with full-disk encryption should be carefully tested, including changing an existing passphrase, adding and removing passphrases, both from the gnome-disks UI and using the cryptsetup CLI.

  
  [Original Description]

  This is fixed upstream. Logging this bug to track the fix in to
  Ubuntu.

  From the upstream bug:

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=928893

  Dear Maintainer,

     * What led up to the situation?

  Install system using normal full disk encryption LUKS+Ext4.
  After install open gnome-disk-utility and change
  encryption password. It gives some error dialog and
  now you are royally screwed. It deleted the only
  LUKS keyslot. Cannot add new keyslots because of that.
  All data will be lost after reboot.

  Here is output of luksdump:

  udo cryptsetup luksDump /dev/sda5
  LUKS header information
  Version: 2
  Epoch: 4
  Metadata area: 16384 [bytes]
  Keyslots area: 16744448 [bytes]
  UUID: 3c16ad4c-294c-4547-bf3e-bb8864ba5ea3
  Label: (no label)
  Subsystem: (no subsystem)
  Flags: (no flags)

  Data segments:
    0: crypt
          offset: 16777216 [bytes]
          length: (whole device)
          cipher: aes-xts-plain64
          sector: 512 [bytes]

  Keyslots:
  Tokens:
  Digests:
    0: pbkdf2
          Hash: sha256
          Iterations: 59904
          Salt: XX XX XX XX XX ....
          Digest: XX XX XX XX XX ...

  ----------------------------------------

  I changed salt and digest. No Keyslots are present!!!

  I tried this 2 times in a row with new install,
  exactly same result.

  -- System Information:
  Debian Release: buster/sid
    APT prefers testing
    APT policy: (500, 'testing')
  Architecture: amd64 (x86_64)
  Foreign Architectures: i386

  Kernel: Linux 5.0.8-xanmod5 (SMP w/2 CPU cores; PREEMPT)
  Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8), LANGUAGE=ru_RU.UTF-8 (charmap=UTF-8)
  Shell: /bin/sh linked to /usr/bin/dash
  Init: systemd (via /run/systemd/system)
  LSM: AppArmor: enabled

  Versions of packages gnome-disk-utility depends on:
  ii dconf-gsettings-backend [gsettings-backend] 0.30.1-2
  ii libatk1.0-0 2.30.0-2
  ii libc6 2.28-10
  ii libcairo2 1.16.0-4
  ii libcanberra-gtk3-0 0.30-7
  ii libdvdread4 6.0.1-1
  ii libgdk-pixbuf2.0-0 2.38.1+dfsg-1
  ii libglib2.0-0 2.58.3-1
  ii libgtk-3-0 3.24.5-1
  ii liblzma5 5.2.4-1
  ii libnotify4 0.7.7-4
  ii libpango-1.0-0 1.42.4-6
  ii libpangocairo-1.0-0 1.42.4-6
  ii libpwquality1 1.4.0-3
  ii libsecret-1-0 0.18.7-1
  ii libsystemd0 241-3
  ii libudisks2-0 2.8.1-4
  ii udisks2 2.8.1-4

  gnome-disk-utility recommends no packages.

  gnome-disk-utility suggests no packages.

  -- no debconf information

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/libblockdev/+bug/1837437/+subscriptions