Logging off logs off other user(s) too

Bug #1066882 reported by Christoph Feenders on 2012-10-15
This bug affects 1 person
Affects Status Importance Assigned to Milestone
lightdm (Ubuntu)

Bug Description

When using the "Switch User" capability of GNOME (Ubuntu 10.04 LTS) or Unity (Ubuntu 12.04 LTS) I sporadically experience the following problem:

Initial Situation:
  User A is logged in.

  1) Select "Log Out" from the panel, then select "Switch User".
  2) Select User B and log in.
  3) After some time log out User B.

  From time to time I find myself back on the login-screen and both users are logged off (with no processes of either of them left running), although logging off User B should not affect User A's processes.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-31-generic 3.2.0-31.50
ProcVersionSignature: Ubuntu 3.2.0-31.50-generic 3.2.28
Uname: Linux 3.2.0-31-generic x86_64
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices: aplay: device_list:252: no soundcards found...
ApportVersion: 2.0.1-0ubuntu13
Architecture: amd64
ArecordDevices: arecord: device_list:252: no soundcards found...
 /dev/snd/controlC1: christoph 25151 F.... pulseaudio
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
Date: Mon Oct 15 15:37:54 2012
HibernationDevice: RESUME=UUID=cc0b3a66-ef3f-452a-be26-56c67e019451
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
 lo no wireless extensions.

 eth1 no wireless extensions.

 eth0 no wireless extensions.
MachineType: System manufacturer System Product Name
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-31-generic root=UUID=e4691ede-9850-4081-8554-1796775aa28a ro quiet splash vt.handoff=7
 linux-restricted-modules-3.2.0-31-generic N/A
 linux-backports-modules-3.2.0-31-generic N/A
 linux-firmware 1.79.1

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/22/2008
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1901
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: Commando
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1901:bd12/22/2008:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnCommando:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer

summary: - Logging off logs off other user(s)
+ Logging off logs off other user(s) too
description: updated
affects: linux (Ubuntu) → lightdm (Ubuntu)

Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.

information type: Private Security → Public
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