Description of problem: Using XFCE with dm-tool lock results in insecure locking of x session that one can circumvent using ctrl+alt+F1 Version-Release number of selected component (if applicable): lightdm 1.10.5 How reproducible: not sure Steps to Reproduce: 1. upgrade from XFCE fedora 21 to fedora 23 using DNF system upgrade path 2. xfconf-query -c xfce4-session -p /general/LockCommand -s "dm-tool lock" --create -t string 3. logind.conf add some ttys (e.g 11) 4. use xfce4-whiskermenu-plugin to lock screen 5. ctrl+alt+F1 Actual results: see unlocked XVFE session Expected results: see locked screen Additional info: I find that installing and running `light-locker` package does fix the issue and session is securely locked. I beliee this is a security issue and dm-tool should always depend on some sceensaver + raise error if no screensaver to actually lock the screen is available. Otherwise one may think the screen is locked while it is not really locked. Or remove the `dm-tool` lock functionality as it is misleading user that that screen is locked while it isn't. Additionally see #1. I am absolutely sure my fedora 21 installation was locking screen properly somehow (I can't rememeber what I used at that time. After upgrade locking magically stopped working so I started to search for a XFCE specific tool to lock screen and found dm-tool. There was no indication whatsoever that it doesn't properly lock until I started switching ttys for unrelated reasons. Here's a related ubuntu bug: https://bugs.launchpad.net/ubuntu/+source/lxsession/+bug/1205384
Here's a debian bug, it looks like dm-tool lock has been removed upstream? https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=740163
Looking at changeset: http://bazaar.launchpad.net/~ubuntu-branches/debian/sid/lxsession/sid/revision/15 I see the change was to remove dm-tool from lxlock. But I don't even have that binary in my fedora 23. I think we should have by default installed on XFCE light-locker and lxlock or hwatever needed to lock the screen.
I think the fix actually should be: * install light-locker mandatory with XFCE (or some other compatible screensaver) * make xflock4 use the installed screensaver for locking: * https://bugzilla.xfce.org/show_bug.cgi?id=3770 * https://bugs.launchpad.net/ubuntu/+source/xfce4-session/+bug/1254366
Here's upstream bug with attached patch: https://bugzilla.xfce.org/show_bug.cgi?id=12415 The thing that fedora maintainer need to do is add extra dependencies such that light-locker is installed as a dependency of xfce4-session. Or some other supported alternative screen locker.
triaging to xfce-session (with my lightdm maintainer hat on, I'm tempted to just remove dm-tool from lightdm, as far as I can tell, I don't think it works as advertised)
@Rex, +1 for removing that dm-tool. Btw I eventually switched off light-locker because it caused switching consoles and once I lock, closing te laptop lid could not suspend the laptop because of consolekit maybe.. not sure. Also I was unable to switch to tty12 to see my system log like I like to do sometimes. IIRC switching consoles caused screen to lock. Removing light-locker and using gnome-screensaver works like a charm though as it doesn't cause any tty switching. So my vote goes to gnome-screensaver.
Well, the default Xfce group/live install has xscreensaver, which should get started by default and be called by xflock4 to lock the screen. If you want to use light-locker you can by setting the xfconf key. Is there any advantage to light-locker over xscreensaver -lock? gnome-screensaver is not a viable option for Xfce. It will never lock on Xfce (unless forced) because the way it tells idle is by pings to gnome-session. This could result in someone thinking they are locking their screen automatically after N minutes, but it never happening.
Moving this back to lightdm... if the lightdm maintainers want to remove dm-tool, thats fine. I dont think there's anything for me to do here.
File the issue upstream https://github.com/canonical/lightdm/issues