sudo apport-kde is in a different design (stripped XDG_CURRENT_DESKTOP)

[Jānis Kangarooo]

[Impact]

Running ubuntu-bug as normal user has the correct theme (see screenshots attached to bug #1881640), but running "sudo ubuntu-bug" has a different, non-matching theme (see attached screenshot). This applies to all Qt applications.

[Test Plan]

This problem can be reproduce by running a KDE application on Ubuntu Desktop (GNOME):

1. Launch ubuntu-22.04-desktop-amd64.iso
2. Install apport-kde
3. Run: /usr/share/apport/apport-kde -f
4. Run: sudo /usr/share/apport/apport-kde -f
5. Compare both windows. They have different icons and font size.

Same result with KDE:

1. Use kubuntu-22.04-desktop-amd64.iso
2. Run ubuntu-bug -f
3. Run: sudo ubuntu-bug -f

[Where problems could occur]
Passing through an additional environment variable could lead to an undesired side effect (if an application expect it not be be set when run as root). Since this environment variable changes the code paths, it could reveal Qt bugs related to running as root.

[Analysis]

Qt needs XDG_CURRENT_DESKTOP to be set to determine the correct theme, but XDG_CURRENT_DESKTOP is not in the list of environment variables to preserve (and not in env_keep in /etc/sudoers).

On other other hand, sudo preserves the DISPLAY environment variable:

$ sudo env | grep -Ev '^(LC|LS|SUDO|LANG|COLOR|TERM|PATH)'
XAUTHORITY=/run/user/1000/gdm/Xauthority
DISPLAY=:0
MAIL=/var/mail/root
LOGNAME=root
USER=root
HOME=/root
SHELL=/bin/bash

[Workaround]

Prevent sudo from dropping XDG_CURRENT_DESKTOP by running: sudo XDG_CURRENT_DESKTOP=$XDG_CURRENT_DESKTOP /usr/share/apport/apport-kde -f

[Other Info]

This changes was accepted upstream: https://github.com/sudo-project/sudo/pull/165

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: apport 2.20.9-0ubuntu7.27
ProcVersionSignature: Ubuntu 5.4.0-94.106~18.04.1-generic 5.4.157
Uname: Linux 5.4.0-94-generic i686
ApportVersion: 2.20.9-0ubuntu7.27
Architecture: i386
CurrentDesktop: KDE
Date: Sun Jan 16 05:04:24 2022
InstallationDate: Installed on 2022-01-15 (0 days ago)
InstallationMedia: Kubuntu 18.04.5 LTS "Bionic Beaver" - Release i386 (20200806.1)
PackageArchitecture: all
SourcePackage: apport
UpgradeStatus: No upgrade log present (probably fresh install)

[Benjamin Drung (bdrung)]

Re-assigning this ticket to sudo. IMO XDG_CURRENT_DESKTOP should be added to the list of environment variables to preserve, e.g. by adding it to env_keep in /etc/sudoers.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dimitri John Ledkov (xnox)]

i wonder if things work fine if called with pkexec.

[Seth Arnold (seth-arnold)]

I'm a bit surprised ubuntu-bug shows a GUI when run under sudo at all. I think I'd expect the usual X11 "no cookies" failure to connect.

Running X programs as another user is bound to be trouble. Perhaps ubuntu-bug should quit immediately if it detects running via sudo, su, etc things?

Thanks

[Benjamin Drung (bdrung)]

Tested with kubuntu-22.04-desktop-amd64.iso. Running "pkexec ubuntu-bug -f" failed to determine that there is a desktop, because neither DESKTOP nor WAYLAND_DISPLAY are set:

$ pkexec env | grep -Ev '^(LC|LS|PATH|TERM|COLOR|LANG)'
SHELL=/bin/bash
LOGNAME=root
USER=root
HOME=/root
PKEXEC_UID=1000

sudo on the other hand preserves XAUTHORITY and DISPLAY.

If you think that apport should not show a GUI when run under sudo, please open a separate bug against apport. This bug report is about sudo. sudo preserves some environment variables to run GUI applications, but not enough to get the theme right.

[Benjamin Drung (bdrung)]

Upstream plugins/sudoers/env.c defines:

static const char *initial_keepenv_table[] = {
    "COLORS",
    "DISPLAY",
    "HOSTNAME",
    "KRB5CCNAME",
    "LS_COLORS",
    "PATH",
    "PS1",
    "PS2",
    "XAUTHORITY",
    "XAUTHORIZATION",
    NULL
};

Debian adds DPKG_COLORS to it.

[Benjamin Drung (bdrung)]

I created an upstream merge request to add XDG_CURRENT_DESKTOP to initial_keepenv_table: https://github.com/sudo-project/sudo/pull/165

[Benjamin Drung (bdrung)]

Uploaded sudo 1.9.10-3ubuntu1 to kinetic and sudo 1.9.9-1ubuntu2.1 to jammy (patch attached).

[Launchpad Janitor (janitor)]

This bug was fixed in the package sudo - 1.9.10-3ubuntu1

---------------
sudo (1.9.10-3ubuntu1) kinetic; urgency=medium

  * Merge from Debian unstable. Remaining changes:
    - debian/control:
      + Build-Conflicts on fakeroot (<< 1.25.3-1.1ubuntu1)
    - debian/sudo[-ldap].manpages: install man/man8/sudo_root.8
    - debian/sudo[-ldap].init: delete init scripts, as they are no longer
      necessary.
    - debian/etc/pam.d/sudo[-i]:
      + Use pam_env to read /etc/environment and /etc/default/locale
        environment files. Reading ~/.pam_environment is not permitted due
        to security reasons.
    - debian/etc/sudoers:
      + also grant admin group sudo access
      + include /snap/bin in the secure_path
    - debian/tests/control: 03-getroot-ldap:
      + allow removal of 'sudo' in autopkgtest (SUDO_FORCE_REMOVE=yes)
  * Dropped changes (applied in Debian):
    - debian/rules:
      + compile with --without-lecture --with-tty-tickets --enable-admin-flag
  * Add XDG_CURRENT_DESKTOP to initial_keepenv_table for Qt to determine the
    correct theme (LP: #1958055)

sudo (1.9.10-3) unstable; urgency=medium

  * some changes to 03-getroot-ldap autopkgtest to find out
    about ppc64el failure

sudo (1.9.10-2) unstable; urgency=medium

  * upload to unstable (fixed autopkgtest is needed to allow
    adduser to migrate)

sudo (1.9.10-1) experimental; urgency=medium

  * new upstream version
    * unverified upstream changelog
    * implement workaround if /proc/self/stat is invalid.
      (Closes: #940533)
    * Fix compilation problem on kFreeBSD. (Closes: #1004909)
      (different fix than the Debian patch, disable Debian patch)
    * get rid of e-mails "problem with defaults entries" in sss
      configurations. (Closes: #793660)
    * regular expression support for sudoers. (Closes: #945366)
    * handle /proc/self/fd in qemu.
    * Apply Upstream Patch to allow test suite with non-english LANG
      https://bugzilla.sudo.ws/show_bug.cgi?id=1025
    * Apply Upstream Patch to allow test suite with faketime
  * re-introduce MVPROG patch that got lost in dh migration.
    Thanks to Vagrant Cascadian (Closes: #976307)
  * revert back to directly shipping the mask symlink in the package.
    Thanks to Michael Biebl (Closes: #1004730)
  * adopt configure changes from Ubuntu
    --without-lecture --with-tty-tickets --enable-admin-flag (Closes: #1006273)
  * fix wrong handling of --with-systemd-tmpfiles.d
  * bring OPTIONS up to date.
  * have upstream install docs directly to correct directory
  * let debhelper handle the upstream changelog
  * remove LICENSE.md in both packages
  * autopkgtest: send deluser stderr to null in cleanup
  * Add cron to autopkgtest 03-getroot-ldap dependencies
  * improve lintian overrides

 -- Benjamin Drung <email address hidden> Wed, 03 Aug 2022 10:45:04 +0200

[Steve Langasek (vorlon)]

This bug report lacks the 'Where problems could occur' section of the SRU bug template.

[Benjamin Drung (bdrung)]

Added 'Where problems could occur' section.

[Robie Basak (racb)]

Is there any possibility that passing through this environment variable when we previously did not will change behaviour in such a way that a user treats that as a regression? For example, if some user has a setting that causes some app to now break, when it didn't before?

Your upload changes the mode of debian/source_sudo.py. I presume this is a mistake?

[Robie Basak (racb)]

An upload of sudo to jammy-proposed has been rejected from the upload queue for the following reason: "The mode of debian/source_sudo.py is changed but this is not explained in the changelog or SRU information".

[Benjamin Drung (bdrung)]

The change of the mode of debian/source_sudo.py was unintentional (I used the git checkout from Debian to put the changes on top). I reuploaded the jammy SRU without the mode change of debian/source_sudo.py.

> Is there any possibility that passing through this environment variable when we previously did not will change behaviour in such a way that a user treats that as a regression? For example, if some user has a setting that causes some app to now break, when it didn't before?

XDG_CURRENT_DESKTOP is probably only taken into account by UI applications. If setting this variable causes a code path change and a regression for this one, the same regression should be triggered by running the application without sudo.

If the user blocked passing environment variables like DISPLAY, setting only XDG_CURRENT_DESKTOP did not made UI applications start (tested with: sudo env -i XDG_CURRENT_DESKTOP=$XDG_CURRENT_DESKTOP gnome-calculator)

[Robie Basak (racb)]

Hello Kangarooo, or anyone else affected,

Accepted sudo into jammy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/sudo/1.9.9-1ubuntu2.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-jammy to verification-done-jammy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-jammy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted sudo (1.9.9-1ubuntu2.1) for jammy have finished running.
The following regressions have been reported in tests triggered by the package:

gvfs/1.48.2-0ubuntu1 (amd64)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/jammy/update_excuses.html#sudo

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Benjamin Drung (bdrung)]

Upgraded sudo and verified that /usr/share/apport/apport-kde looks the same when started with sudo.

[Chris Halse Rogers (raof)]

The verification of the Stable Release Update for sudo has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package sudo - 1.9.9-1ubuntu2.1

---------------
sudo (1.9.9-1ubuntu2.1) jammy; urgency=medium

  * Add XDG_CURRENT_DESKTOP to initial_keepenv_table for Qt to determine the
    correct theme (LP: #1958055)

 -- Benjamin Drung <email address hidden> Thu, 04 Aug 2022 12:35:21 +0200