Since a few days, my user groups seem to be missing after loging in via lightdm/slick greeter.
My username is ‘tobias’
When I execute groups I get just my main groups (‘tobias’) while executing sudo -u tobias groups yields ‘tobias adm voice cdrom sudo audio dip video plugdev users lpadmin sambashare pulse pulse-access kvm libvirt docker ntfs libvirt-qemu’
Obviously this is very annoying since it breaks all sorts of permission-related functionality. Additionaly I can’t logout anymore - attempting to do so just restarts the session (I’m logged in again and don’t see the greeter).
Has anyone encountered this problem before or has any clue what could be the cause?
I’ve already tried to reinstall (with --purge) lightdm and slick-greeter, but it did not resolve the issue. However, I’m also trying to restore the default slick-greeter theming now 
- any help on that is also appreciated.
The only hint I could find is the following error in my ‘/var/log/auth.log’:
dbus-daemon[1368]: [system] Rejected send message, 2 matched rules; type="method_call", sender=":1.117" (uid=1000 pid=5252 comm="lightdm --session-child 13 22 " label="unconfined") interface="org.freedesktop.login1.Manager" member="ReleaseSession" error name="(unset)" requested_reply="0" destination="org.freedesktop.login1" (uid=0 pid=1491 comm="/lib/systemd/systemd-logind " label="unconfined")
which seems to occur on any login.
Does the account have enough permissions to create another administrator account?
If yes what happens if you login with that?
I do have the necessary permissions.
I have created a new admin account (“testadmin”) and it shows exactly the same symptoms.
E.g.
$ groups
testadmin
$ sudo -u testadmin groups
testadmin sudo
You could also try sudo apt-get install --reinstall <package name>
That’s precisely what I attempted (with the --purge parameter) for the packages lightdm*, slick-greeter and dbus*.
By best guess is that there’s an issue with the session, would you agree with that? I’m still quite puzzled about where to start troubleshooting…
Thanks for the responses so far!
EDIT: Btw, I have created this bug report on the lightdm bug tracker - but I thought it might as well be an issue with the budgie-desktop (session), so I posted the issue here too.
Nothing to do with budgie
This sounds more like permissions or screwed up /etc/passwd or /etc/groups or one or more of the other /etc files that are installed.
Not sure though how to resolve … but that is generally the area I would look at.
Okay, thanks for your thoughts on it. Is lightdm running as a separate user? In that case this might be the reason why I can see the groups from e.g. a TTY session (or with sudo -u ) but not after graphical login.
Regarding my follow-up problem: What’s the easiest way to restore the slick-greeter theming (after purging the config) to the ubuntu-budgie defaults? Should I look on github for the config files?
Yes . As I understand it there is a lightdm user account
The default theming is via the pocillo gtk theme. So make sure you have that installed.
Oh, so the theme does also change the greeter… Cool.
In that case I probably simply need to change it to something else and back to Pocillo.
Thanks for your help!
The “Login Window” app can be used to change the config of slick-greeter. The default theme is “Pocillo dark” in Login Window. Icon set is gnome
The “Login Window” actually creates a file /etc/lightdm/slick-greeter.conf - so you can remove that (I think) and the defaults will then be inherited by the UB defaults.
Oh, I totally missed that app. Thank you!
Wait, that looks exactly like lightdm-settings 
Did you just relabel that?
it is indeed lightdm-settings - “Login Window” is the name given by the lighdm-settings .desktop file
Ah I see. I was always a bit annoyed (with Gnome itself too) that there is no easy way to find the command of a .desktop file from inside the menu, btw. Maybe that’s something that could be added… It makes it unnecessarily complicated to e.g. execute a program with sudo.
Maybe I’ll make a suggestion for this (e.g. for adding a right-click menu to the applications in the menu).
Use the menu-editor app to view what is being executed by a particular menu option
Yes, that’s what I’m currently doing. But I think there should be an easier way 
A right-click option to edit the menu entry would be very comfortable - not sure if that’s possible with the way, menulibre is integrated.
No - that would need a code change in budgie-desktop to achieve that.
Are you in general accepting pull requests for things like that? I’m definitely interested in digging into the budgie-desktop a bit. I love the feel of it (allthough some things definitely need a bit more time to develop).
Not our call - this is an upstream issue.
The last time someone brought up the ability to edit the menu directly from the budgie menu, upstream closed the issue saying that it was an unnecessary complication and a dedicated tool like menulibre should be used.
EDIT:
upstream is https://github.com/solus-project/budgie-desktop
Debian package is “budgie-desktop”
Hm, editing would be nice, but getting information about an item, executing it with elevated permissions and other things are the more important additions.
Those are things that are required quite often and currently unnecessary cumbersome. But if it’s an upstream issue, I should probably discuss it with the maintainers. Can you point me to the correct package (is it e.g. gnome-shell)?
Thanks for the answer