Running Steam Proton Games in Firejail

#TechnoPosts

Proton by Valve has greatly increased the number of playable games on Linux, but almost all games running in proton break when Steam is run from firejail.

A couple fixes can be introduced to allow Proton games to run, the errors referred to here come from running Steam from a terminal and watching the feed (just type "steam" into a terminal and hit 'Enter').

#/usr/bin/env: 'python3': Permission denied

Edit /etc/firejail/steam.profile and add the line:

noblacklist /usr/bin/python*

Voila!

ERROR: ld.so: home '/home/user/.local/share/Steam/ubuntu1232/gameoverlayrenderer.so' from LDPRELOAD cannot be preloaded (wrong ELF class: ELFCLASS32): ignored

Edit /etc/firejail/steam.profile and comment out "seccomp" with "#", like so:

#seccomp

This will expose a lot of kernel surface area, reducing the effectiveness of Firejail in protecting the remainder of the operating system from a compromised steam client or a game launched within it. You have to decide if it is worth the games you are playing.

Also consider not playing games on a machine that needs security, you can always buy a chromebook for banking or shopping.

A more open seccomp filter could be generated by running strace on steam, but I am too lazy to do this myself. I once tried, but the syntax of Firejail was undocumented and a lot of syscalls I tried to add to a whitelist from strace were considered invalid to firejail.

Additional problems can sometimes be fixed by removing the steam overlay for a game.

Hope this helps someone; Glory to Linux