Review Request 126115: Unset environment variables before starting kwin_wayland

[Matthias Klumpp]

> On Nov. 19, 2015, 12:26 nachm., Sebastian Kügler wrote:
> > Possibly naive question: How would I use it with my custom-build setup, where I need vars like QT_PLUGIN_PATH, etc. set to be able to start the binaries at all?
> 
> Martin Gräßlin wrote:
>     I don't have a solution for it yet and yes it also affects my setup. I hope qt.conf can be used, but I don't know yet.

A possible solution to that problem is to allow setting this in a system-wide configuration file, or create a special KDE-specific configuration which sets the script to a "debug mode", which doesn't filter env vars.
The important thing is that you need root access to modify these settings (set it to debug mode or set additional variables).


- Matthias


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On Nov. 19, 2015, 12:22 nachm., Martin Gräßlin wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/126115/
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> 
> (Updated Nov. 19, 2015, 12:22 nachm.)
> 
> 
> Review request for Plasma, David Edmundson and Matthias Klumpp.
> 
> 
> Repository: plasma-workspace
> 
> 
> Description
> -------
> 
> Any environment variable which can be used to specify a path to a
> binary object to be loaded in the KWin process bears the risk of
> being abused to add code to KWin to perform as a key logger.
> 
> E.g. an env variable pointing QT_PLUGIN_PATH to a location in $HOME
> and adjusting QT_STYLE_OVERRIDE to load a specific QStyle plugin from
> that location would allow to easily log all keys without KWin noticing.
> 
> As env variables can be specified in scripts sourced before the session
> starts there is not much KWin can do about that to protect itself.
> 
> This affects all the LD_* variables and any library KWin uses and
> loads plugins.
> 
> The list here is based on what I could find:
> * LD_* variables as specified in the man page
> * LIBGL_* and EGL_* as specified on mesa page
> * QT_* variables based on "git grep qgetenv" in qtbase and qtdeclarative
>   combined with Qt's documentation
> * "git grep getenv" in various KDE frameworks based on ldd output of KWin
> 
> Unfortunately the list is unlikely to be complete. If one env variable is
> missed, there is a risk. Even more each change in any library might
> introduce new variables.
> 
> The approach is futile, but needed till Linux has a secure way to start
> the session without sourcing env variable scripts from user owned
> locations.
> 
> 
> Diffs
> -----
> 
>   startkde/startplasmacompositor.cmake 1e46e5be0a0d733fb01e1a87a34ee3c73a06bf8c 
> 
> Diff: https://git.reviewboard.kde.org/r/126115/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Martin Gräßlin
> 
>

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