[Bug 1597876] [NEW] installing/upgrading packages containing systemd services results in prompt for cryptoswap passphrase [xenial]

Thu Jun 30 18:29:21 UTC 2016

Public bug reported:

This is an extremely odd bug that requires a very specific scenario to
reproduce:

1) You need to be using an ecryptfs-style cryptoswap partition (as would
be setup when you choose "Encrypt my home directory" during the
installation)

2) The underlying physical swap partition used for the cryptoswap needs
to be on a GPT partitioned drive

3) The GUID specific bit 63 ("no auto mounting") must *not* be set on
the underlying physical swap partition

In this scenario, installing/upgrading/reinstalling seemingly *any*
package with a systemd service will result in the user getting *twice*
prompted for a passphrase to unlock their cryptoswap partition. If
upgrades are performed using the graphical Software Updater, the user
wont be aware of this issue unless they've expanded the details,
resulting in the Software Updater hanging indefinitely.

For example, if you have the needed setup, you can easily reproduce this
bug with:

sudo apt-get install --reinstall whoopsie

After which you'll encounter something like this:

(Reading database ... 177827 files and directories currently installed.)
Preparing to unpack .../whoopsie_0.2.52.1_amd64.deb ...
Please enter passphrase for disk primary (cryptswap1) on none! 
Unpacking whoopsie (0.2.52.1) over (0.2.52) ...
Preparing to unpack .../libwhoopsie0_0.2.52.1_amd64.deb ...
Unpacking libwhoopsie0:amd64 (0.2.52.1) over (0.2.52) ...
Processing triggers for systemd (229-4ubuntu6) ...
Processing triggers for ureadahead (0.100.0-19) ...
ureadahead will be reprofiled on next reboot
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Setting up libwhoopsie0:amd64 (0.2.52.1) ...
Setting up whoopsie (0.2.52.1) ...
Please enter passphrase for disk primary (cryptswap1) on none! 
Processing triggers for libc-bin (2.23-0ubuntu3) ...

(You can just hit enter each time the "Please enter passphrase for..."
prompt comes up.)

For some background: in modern systemd times, ecryptfs-style cryptoswaps
are broken when the underlying physical GPT swap partition does not have
bit 63 set:

https://bugs.launchpad.net/ubuntu/+source/ecryptfs-utils/+bug/1447282

During the boot the user is erroneously prompted for a passpharase to
unlock the cryptoswap (you can hit enter for an empty passphrase, or
enter any passphrase you want... either way, nothing seems to actually
be done with it). After the boot completes, the underlying physical swap
partition will be mounted normally (ie, you wont actually be using
encrypted swap... so a false sense of security, which is of course
concerning).

Although lp:1447282 has been fixed for the most common hardware
configurations, it's still possible for users to encounter this problem
in the real-word: ecryptfs-setup-swap currently fails to set bit 63 when
the physical GPT swap partition is on an NVMe or MMC drive:

https://bugs.launchpad.net/ecryptfs/+bug/1597154

So one way to reproduce this is to install Ubuntu 16.04 onto an NVMe
drive and choose "Encrypt my home directory" during the installation.

To make debugging this easier without requiring an NVMe drive (and
especially so it's easier to debug in a UEFI VM), I'm attaching a script
that will unset bit 63 on the underlying GPT swap partitions used by any
ecryptfs-style cryptoswaps that are present.

If you run my script:

sudo python3 unset-bit-63.py

And then reboot, you should now be able to reproduce this bug.

Even though fixing lp:1597154 will mean users shouldn't encounter
(during normal real-world usage) this strange behavior when
installing/upgrading/reinstalling packages that contain systemd
services, I have a strong hunch that the fact this can happen at all
indicates something is quite wonky in either systemd itself or in the
Debian/Ubuntu specific systemd trigger handling.

Thanks!

** Affects: systemd (Ubuntu)
     Importance: Undecided
         Status: New

** Attachment added: "unset-bit-63.py"
   https://bugs.launchpad.net/bugs/1597876/+attachment/4692952/+files/unset-bit-63.py

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https://bugs.launchpad.net/bugs/1597876

Title:
  installing/upgrading packages containing systemd services results in
  prompt for cryptoswap passphrase [xenial]

Status in systemd package in Ubuntu:
  New

Bug description:
  This is an extremely odd bug that requires a very specific scenario to
  reproduce:

  1) You need to be using an ecryptfs-style cryptoswap partition (as
  would be setup when you choose "Encrypt my home directory" during the
  installation)

  2) The underlying physical swap partition used for the cryptoswap
  needs to be on a GPT partitioned drive

  3) The GUID specific bit 63 ("no auto mounting") must *not* be set on
  the underlying physical swap partition

  In this scenario, installing/upgrading/reinstalling seemingly *any*
  package with a systemd service will result in the user getting *twice*
  prompted for a passphrase to unlock their cryptoswap partition. If
  upgrades are performed using the graphical Software Updater, the user
  wont be aware of this issue unless they've expanded the details,
  resulting in the Software Updater hanging indefinitely.

  For example, if you have the needed setup, you can easily reproduce
  this bug with:

  sudo apt-get install --reinstall whoopsie

  After which you'll encounter something like this:

  (Reading database ... 177827 files and directories currently installed.)
  Preparing to unpack .../whoopsie_0.2.52.1_amd64.deb ...
  Please enter passphrase for disk primary (cryptswap1) on none! 
  Unpacking whoopsie (0.2.52.1) over (0.2.52) ...
  Preparing to unpack .../libwhoopsie0_0.2.52.1_amd64.deb ...
  Unpacking libwhoopsie0:amd64 (0.2.52.1) over (0.2.52) ...
  Processing triggers for systemd (229-4ubuntu6) ...
  Processing triggers for ureadahead (0.100.0-19) ...
  ureadahead will be reprofiled on next reboot
  Processing triggers for libc-bin (2.23-0ubuntu3) ...
  Setting up libwhoopsie0:amd64 (0.2.52.1) ...
  Setting up whoopsie (0.2.52.1) ...
  Please enter passphrase for disk primary (cryptswap1) on none! 
  Processing triggers for libc-bin (2.23-0ubuntu3) ...

  (You can just hit enter each time the "Please enter passphrase for..."
  prompt comes up.)

  For some background: in modern systemd times, ecryptfs-style
  cryptoswaps are broken when the underlying physical GPT swap partition
  does not have bit 63 set:

  https://bugs.launchpad.net/ubuntu/+source/ecryptfs-utils/+bug/1447282

  During the boot the user is erroneously prompted for a passpharase to
  unlock the cryptoswap (you can hit enter for an empty passphrase, or
  enter any passphrase you want... either way, nothing seems to actually
  be done with it). After the boot completes, the underlying physical
  swap partition will be mounted normally (ie, you wont actually be
  using encrypted swap... so a false sense of security, which is of
  course concerning).

  Although lp:1447282 has been fixed for the most common hardware
  configurations, it's still possible for users to encounter this
  problem in the real-word: ecryptfs-setup-swap currently fails to set
  bit 63 when the physical GPT swap partition is on an NVMe or MMC
  drive:

  https://bugs.launchpad.net/ecryptfs/+bug/1597154

  So one way to reproduce this is to install Ubuntu 16.04 onto an NVMe
  drive and choose "Encrypt my home directory" during the installation.

  To make debugging this easier without requiring an NVMe drive (and
  especially so it's easier to debug in a UEFI VM), I'm attaching a
  script that will unset bit 63 on the underlying GPT swap partitions
  used by any ecryptfs-style cryptoswaps that are present.

  If you run my script:

  sudo python3 unset-bit-63.py

  And then reboot, you should now be able to reproduce this bug.

  Even though fixing lp:1597154 will mean users shouldn't encounter
  (during normal real-world usage) this strange behavior when
  installing/upgrading/reinstalling packages that contain systemd
  services, I have a strong hunch that the fact this can happen at all
  indicates something is quite wonky in either systemd itself or in the
  Debian/Ubuntu specific systemd trigger handling.

  Thanks!

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