kdesudo "cannot connect to X server" after upgrade to 12.04

[themroc]

After upgrading from Kubuntu amd64 11.10 to 12.04 any application, which use kdesudo doesn't work any longer.

e.g. edit software sources, synaptic, krusader root-mode, ...

After enter my password nothing happens.

So I test kdesudo in the terminal:

kdesudo kwrite
(In the popup-windows I enter my password and push enter or OK)
Answer in terminal:
kwrite: cannot connect to X server

[themroc (rauchweihe)]

I have found a solution of the described problem:

I had have this additional entries in my /etc/sudoers:

# Allow proxy environment variables to pass through
Defaults env_keep="no_proxy NO_PROXY"
Defaults env_keep+="all_proxy ALL_PROXY"
Defaults env_keep+="http_proxy HTTP_PROXY"
Defaults env_keep+="https_proxy HTTPS_PROXY"
Defaults env_keep+="ftp_proxy FTP_PROXY"

After deleting this two entries

Defaults env_keep="no_proxy NO_PROXY"
Defaults env_keep+="all_proxy ALL_PROXY"

kdesudo works again.

Note, the environment variables NO_PROXY ans ALL_PROXY are not defined for my normal users, so perhaps this was the reason, why kdesudo fails in Kubuntu 12.04.

[Denise Brooks (denise-d-brooks)]

I am having exactly the same problem. I set up a Kubuntu /Win8 dual boot on an Asus zenbook. ubuntu boots, and then brings up the nice dual boot screen, but when I pick ubuntu, I just get the wallpaper but no kde gui. When I alt-ctl-F1 into terminal, and try something like kdesudo kate, I get kdesudo: cannot connect to X server.

I don't have any of the entries that themroc has in /etc/sudoers. This is a totally fresh install.

[Jonathan Riddell (jr)]

Densie your problem sounds different to the bug reporter's problem, I wouldn't expect kdesudo to work from a linux console. I recomment looking in ~/.xsession-errors and lots in /var/log and filing a new bug

[Harald Sitter (apachelogger)]

Denise, you'll have to export the DISPLAY variable to start GUI applications from a TTY.

e.g.
export DISPLAY=:0
kdesudo kate

Indeed not related to the report, nor is it a bug.

[David Pérez (david-perez-ingeniero)]

Working with Linux Mint Rebecca (based in Ubuntu 14.04).

I have this in /etc/sudoers:

    Defaults env_keep = "http_proxy https_proxy ftp_proxy"

If I comment this line, I can run e.g.
    kdesudo partitionmanager

otherwise I get this error:
    "cannot connect to X server"

[Jonathan Riddell (jr)]

kdesudo has moved to KDE infrastructure.

If you feel your bug is still relevant please open a new bug on bugs.kde.org

https://bugs.kde.org/describecomponents.cgi?product=kdesudo