Locking the screen doesn't really lock under certain circumstances

[Donarsson]

When the screen is locked while an action causes a window to gain focus, it allows full keyboard interaction with the locked session. I was able to trigger this behaviour doing one of the following:

* Changing to a desktop with at least one window on it and, without releasing Ctrl+Alt, pressing L to lock the screen
* While dragging a window, lock the screen using the keyboard shortcut
* While Alt+Tab-ing, lock the screen without releasing the Alt key

In all cases, a window can gain focus after the screen was locked and all keyboard input goes to that window. Also, the window switcher remains fully functional and even shows the window previews like it would normally. It's even possible to open applications using keyboard shortcuts, for example a terminal.
To enter the password and unlock the session, the password field needs to be focused by opening and closing an indicator in the lockscreen and then clicking the password field.

While most of these actions aren't something a normal user would do, they clearly show that the new lockscreen is far less secure than the old one. The first trigger action is even something I've done in the past during normal use, switching to a desktop and then locking the session, so I would say there is at least a small "real" security risk in this.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.1.2+14.04.20140311-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-17.37-generic 3.13.6
Uname: Linux 3.13.0-17-generic x86_64
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CurrentDesktop: Unity
Date: Wed Mar 12 18:36:09 2014
InstallationDate: Installed on 2014-02-24 (16 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140223)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)

[Stephen M. Webb (bregma)]

Fix Released in Unity Unity 7.2.0.

[Matthias Geheim (matthias-geheim)]

I've got unity 7.2.2+14.04.20140714-0ubuntu1 installed and sometimes (~every 3rd time) i'm still able to perform keyboard inputs to applications, when the screen is locked. When this happens, I can't type to the password field. I have to klick around on the indicators, to get focus back to lockscreen.