Ubuntu
gdm3 package

Black screen if PAM session fails to initialize completely

Bug #1935818 reported by Jean-Baptiste Lallement
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
gdm3 (Ubuntu)
Fix Released
High
Unassigned
Focal
Fix Released
High
Unassigned
Ubuntu ubuntu-20.04.3

Bug Description

[Description]
If PAM session fails to initialize completely, the session aborts as expected but GDM stays on VT1 and switches to a black screen. This is the case for example, when requirement to start a session are not met and the session start up has to be aborted.

[Test Plan]
1. In /etc/pam.d/gdm-password insert the line:
    session requisite pam_deny.so
After the line
    @include common-account
2. Login from GDM
3. Verify that:
  - The session fails to start
  - A black TTY is displayed
  - Active TTY is 1
4. Apply the patched version
5. Login from GDM
6. Verify the login fails but GDM is still displayed and an error message in printed under the password box.

[Where problem could occur]
* Cannot login at all with any user.

[Other info]
* Upstream bug report and patch:
  https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/143

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: gdm3 3.38.2.1-3ubuntu2
ProcVersionSignature: Ubuntu 5.11.0-20.21+21.10.1-generic 5.11.21
Uname: Linux 5.11.0-20-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu67
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Mon Jul 12 11:36:11 2021
InstallationDate: Installed on 2020-05-31 (407 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Alpha amd64 (20200527)
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

See original description
Revision history for this message
Jean-Baptiste Lallement (jibel) wrote :
description: updated
Changed in gdm3 (Ubuntu):
importance: Undecided → High
status: New → Triaged
description: updated
Changed in gdm3 (Ubuntu Focal):
assignee: nobody → Jean-Baptiste Lallement (jibel)
milestone: none → ubuntu-20.04.3
Daniel van Vugt (vanvugt)
tags: added: fixed-in-3.38.3 fixed-upstream
tags: added: fixed-in-40.1
Revision history for this message
Brian Murray (brian-murray) wrote :

  [ Laurent Bigonville ]
  * debian/rules: Drop compatibility symlinks now that bullseye is released
  * debian/watch: Update the watch file to follow the new version scheme
  * debian/control.in: Suggest orca instead of gnome-orca, the later is a transitonal package

  [ Marco Trevisan (Treviño) ]
  * debian/patches:
    - Refresh
    - Correctly handle session opening errors (LP: #1935818)
    - Emit specific error on session opened failure

 -- Marco Trevisan (Treviño) <email address hidden> Sat, 10 Jul 2021 18:28:45 +0200

Changed in gdm3 (Ubuntu):
status: Triaged → Fix Committed
Changed in gdm3 (Ubuntu Focal):
status: New → Fix Committed
tags: added: verification-needed verification-needed-focal
Revision history for this message
Brian Murray (brian-murray) wrote : Please test proposed package

Hello Jean-Baptiste, or anyone else affected,

Accepted gdm3 into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/gdm3/3.36.3-0ubuntu0.20.04.4 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-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. 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.

Revision history for this message
Pierre Equoy (pieq) wrote :

Verified OK on focal-proposed using gdm3 3.36.3-0ubuntu0.20.04.4

Jean-Baptiste Lallement (jibel)
tags: added: verification-done verification-done-focal
removed: verification-needed verification-needed-focal
Changed in gdm3 (Ubuntu Focal):
assignee: Jean-Baptiste Lallement (jibel) → nobody
Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package gdm3 - 3.38.2.1-3ubuntu3

---------------
gdm3 (3.38.2.1-3ubuntu3) impish; urgency=medium

  [ Laurent Bigonville ]
  * debian/rules: Drop compatibility symlinks now that bullseye is released
  * debian/watch: Update the watch file to follow the new version scheme
  * debian/control.in: Suggest orca instead of gnome-orca, the later is a transitonal package

  [ Marco Trevisan (Treviño) ]
  * debian/patches:
    - Refresh
    - Correctly handle session opening errors (LP: #1935818)
    - Emit specific error on session opened failure

 -- Marco Trevisan (Treviño) <email address hidden> Sat, 10 Jul 2021 18:28:45 +0200

Changed in gdm3 (Ubuntu):
status: Fix Committed → Fix Released
Adolfo Jayme Barrientos (fitojb)
Changed in gdm3 (Ubuntu Focal):
importance: Undecided → High
Revision history for this message
Chris Halse Rogers (raof) wrote : Update Released

The verification of the Stable Release Update for gdm3 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.

Revision history for this message
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package gdm3 - 3.36.3-0ubuntu0.20.04.4

---------------
gdm3 (3.36.3-0ubuntu0.20.04.4) focal; urgency=medium

  * debian/patches/ubuntu/reset-session-on-pam-error.patch:
    - Backport upstream commit to fix ending up on a black screen when pam
      session errors out. (LP: #1935818)

 -- Didier Roche <email address hidden> Mon, 12 Jul 2021 11:44:23 +0200

Changed in gdm3 (Ubuntu Focal):
status: Fix Committed → Fix Released
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