Bug 510968

Summary: Environment variables starting without digits are not filtered
Product: [Frameworks and Libraries] frameworks-kio Reporter: N <equaa>
Component: generalAssignee: KIO Bugs <kio-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: christoph, equaa, kdelibs-bugs-null, nate
Priority: NOR    
Version First Reported In: 6.19.0   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: https://invent.kde.org/frameworks/kio/-/commit/292fadb4cce90ade731330ee126cd829232e37df Version Fixed/Implemented In: 6.21
Sentry Crash Report:
Attachments: test case, sets env 0 and then runs a bash shell

Description N 2025-10-23 16:18:43 UTC 
Created attachment 186046 [details]
test case, sets env 0 and then runs a bash shell

SUMMARY
When launching a process with xdg-open via kio's systemd process launcher, environment variables whose names are not made of [a-zA-Z0-9_]* are filtered to fit systemd unit files[1]; but systemd has an additional restriction that environment variables not start with digits[2]. If an environment variable like "0a" is set, the process will fail to launch.

STEPS TO REPRODUCE
1. Set an environment variable starting with "0". (Ex: setenv.c)
2. Run xdg-open somefile.png

OBSERVED RESULT
kf.kio.gui: Failed to launch process as service: "app-firefox@[...].service" "org.freedesktop.DBus.Error.InvalidArgs" "Invalid environment block."

EXPECTED RESULT
The environment should be filtered alongside other illegal systemd environment variables.

SOFTWARE/OS VERSIONS
Operating System: NixOS 25.05
KDE Plasma Version: 6.3.6
KDE Frameworks Version: 6.14.0
Qt Version: 6.9.1
xdg-utils 1.2.1
kio-6.14.0

ADDITIONAL INFORMATION
[1] https://invent.kde.org/frameworks/kio/-/blob/67fa68b82e1795f636936b4f77623d0146f2ee8e/src/gui/systemd/systemdprocessrunner.cpp#L94
[2] https://www.freedesktop.org/software/systemd/man/latest/systemd.exec.html#Environment=
Comment 1 Bug Janitor Service 2025-11-08 17:12:34 UTC 
A possibly relevant merge request was started @ https://invent.kde.org/frameworks/kio/-/merge_requests/2050
Comment 2 Christoph Cullmann 2025-11-08 17:16:01 UTC 
Could you try my patch?
Comment 3 Méven 2025-11-16 14:24:47 UTC 
Git commit 292fadb4cce90ade731330ee126cd829232e37df by Méven Car, on behalf of Christoph Cullmann.
Committed on 16/11/2025 at 14:24.
Pushed by meven into branch 'master'.

systemd: prevent passing invalid env vars starting with digit

filter them out, too
for safety: filter empty vars, should not happen, but still

M  +1    -1    src/gui/systemd/systemdprocessrunner.cpp

https://invent.kde.org/frameworks/kio/-/commit/292fadb4cce90ade731330ee126cd829232e37df