Cannot elevate to root in GUI/desktop

[jelabarre59]

Whenever I run any applications that would prompt me for my password for sudo (USB Image Writer, gparted, etc), all I get is some flickering dialogue box that *should* be prompting me for a password, but instead it seems it's immediately failing on the password prompt without ever taking a password, and the dialogue immediately goes away. I can use sudo and gksudo from a command line with no problem, but this requires me to know what the specific command for that menu entry is (USB Image Writer is the same utility as the USB formatter, just different command switches. That also fails, obviously).

It would seem to be a problem in my profile, since I don't have this happening in other machines.

[austin.texas]

I can't say that I understand what is causing that problem. It could be a problem with pkexec instead of sudo.
Just to check your profile, post the result of the command:

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find $HOME -not -user $USER -exec ls -lad {} \;

[jelabarre59]

I can't say that I understand what is causing that problem. It could be a problem with pkexec instead of sudo.
Just to check your profile, post the result of the command:

Code: Select all

find $HOME -not -user $USER -exec ls -lad {} \;

(I didn't set the original post to notify me of replies, so only just seeing this one)

Tried that command, and the only files not owned by me are some files in my source-code subdir, and my anbox emulator (none of which would interface with the system utilities). Thus far I get failures with USB Image Writer/USB Formatter (they work off the same executable), the "LightDM GTK Greeter settings", Grub-Customizer, GParted, and some other similar ones that I can't remember immediately.

[karlchen]

Hello, jelabarre59.

I just checked here on my Ubuntu 16.04.4. The application menu item "GParted" launches the command gparted-pkexec. I.e. the user id switch to root is not done by gksudo, but by pkexec.
What you could try in order to find out whether it is this pkexec which causes the problem to you is this:

• Open a terminal window.
• Launch GParted by executing

  Code: Select all

  gksudo gparted

  This works correctly? Right?
  Close GParted again.
• Launch GParted by executing

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  gparted-pkexec

  Does it work when invoked from the commandline? Does the terminal window display any error messages? In case it does, please, post them here.

Best regards,
Karl

[jelabarre59]

I just checked here on my Ubuntu 16.04.4. The application menu item "GParted" launches the command gparted-pkexec. I.e. the user id switch to root is not done by gksudo, but by pkexec.
What you could try in order to find out whether it is this pkexec which causes the problem to you is this:

• Open a terminal window.
• Launch GParted by executing

  Code: Select all

  gksudo gparted

  This works correctly? Right?
  Close GParted again.
• Launch GParted by executing

  Code: Select all

  gparted-pkexec

  Does it work when invoked from the commandline? Does the terminal window display any error messages? In case it does, please, post them here.

"gksudo gparted" works fine (have had to do that before, but some other tools want to behave differently depending on how they're called). "gparted-pkexec" fails.

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~ $ gparted-pkexec
Error executing command as another user: Not authorized

This incident has been reported.

[karlchen]

Hello, jelabarre59.

Sorry for not coming back earlier. - Could you, please, check whether the executable has still got its "s" bit on the owner:

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ls -l /usr/bin/pkexec

This should return

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$ ls -l /usr/bin/pkexec
-rwsr-xr-x 1 root root 23376 Jan 18  2016 /usr/bin/pkexec

Note the initial rwsr.

Best regards,
Karl

[jelabarre59]

Same permissions here, date is almost the same.

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-rwsr-xr-x 1 root root 23376 Jan 17  2016 /usr/bin/pkexec

[Flemur]

Code: Select all

~ $ gparted-pkexec
Error executing command as another user: Not authorized
This incident has been reported.

I get the same thing, but with more fluff:
$ gparted-pkexec

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==== AUTHENTICATING FOR com.ubuntu.pkexec.gparted ===
Authentication is required to run the GParted Partition Editor
Authenticating as: lemur,,, (lemur)
Password: 
polkit-agent-helper-1: error response to PolicyKit daemon: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: No session for cookie
==== AUTHENTICATION FAILED ===
Error executing command as another user: Not authorized

This incident has been reported.

In another thread it was reported that "gksudo" is going away, to be replaced by this buggy, touchy "pkexec" and "admin:///" stuff (from freedesktop.org!).

FWIW, I wrote a simple replacement for gksudo:
$ cat bin/Gksudo

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#!/bin/sh
#
xfce4-terminal --command="sudo -H -i -u root bash -c '$*' &" --geometry=45x10 

I tested it with thunar and firefox and it doesn't change settings in your $HOME or take ownership of any files. So far...

In one way it's actually better than the original gksudo because there's a (small) terminal which shows error messages and such.

PS: check :

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ls /usr/share/polkit-1/actions/*part*
/usr/share/polkit-1/actions/com.ubuntu.pkexec.gparted.policy