<alt>+<PrtScreen>+<k> works even though Screen is locked

[Wuestenschiff]

Not quite sure if this is a BUG, but besause it can result in dataloss I report it nevertheless.

<alt>+<PrtScreen>+<k> works even though Screen is locked

Of course I could deaktivate the command in /proc/sys/kernel/sysrq but I would rather like not to. And allow this combination to work can resolt in dataloss, If there is unsaved work in the session.

Reproduce:
- SAVE YOUR WORK!!
- set /proc/sys/kernel/sysrq to 1 (Ubuntu default)
- lock your screen
- <alt>+<PrtScreen>+<k>

Expected behavior:
-gnome-screensaver should intercept the command.

Actual behaviour:
- All processes incl. X-Server are killed you will get to a Login-Screen

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gnome-screensaver 3.4.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.39-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Tue May 29 19:40:21 2012
EcryptfsInUse: Yes
GnomeSessionIdleInhibited: No
GnomeSessionInhibitors: None
GsettingsGnomeSession:
 org.gnome.desktop.session idle-delay uint32 600
 org.gnome.desktop.session session-name 'ubuntu'
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
SourcePackage: gnome-screensaver
Symptom: security
Title: Screen locking issue
UpgradeStatus: Upgraded to precise on 2012-05-21 (8 days ago)
WindowManager: No value set for `/desktop/gnome/session/required_components/windowmanager'

[Wuestenschiff (wuestenschiff)]

Admitting it a duplicate. But maybe it would be easier to forbid sysrq in gnome-screensaver (if technical possible) than change the system globally. Would reduce the implications of the bug tremendously.

[Marc Deslauriers (mdeslaur)]

It's not possible for gnome-screensaver to intercept the key combination as it is handled at the kernel level.