Hi there, I am the co-maintainer of boinc-client [1]. boinc-client runs as a service, and both it and its working units run as 'boinc' user and they are confined by SELinux. Recently, I investigated to figure out why boinc-client, while running as a service, could not detect videocard for GPU calculus. In order to fix this problem I had to add Group=video to boinc-client systemd unit file. I have not yet pushed such change to boinc-client Fedora git, because I would like to ask you if this can cause a breach into boinc-client confinement. I mean, I am wondering if a process that can have access to videocard, could for example read what you are doing on your machine, the passwords you copy and paste, etc. What do you think about?
Best regards
For convenience I attached boinc-client unit file
================================= [Unit] Description=Berkeley Open Infrastructure Network Computing Client Documentation=man:boinc(1) After=network-online.target
[Service] Type=forking Nice=10 User=boinc WorkingDirectory=/var/lib/boinc ExecStart=/usr/bin/boinc_client --daemon --start_delay 1 ExecStop=/usr/bin/boinccmd --quit ExecReload=/usr/bin/boinccmd --read_cc_config ExecStopPost=/bin/rm -f /var/lib/boinc/lockfile IOSchedulingClass=idle Environment=LD_LIBRARY_PATH=/opt/amdgpu-pro/lib64 Group=video
[Install] WantedBy=multi-user.target =================================
[1]: https://admin.fedoraproject.org/pkgdb/package/rpms/boinc-client/
Ah, forget the line Environment=LD_LIBRARY_PATH=/opt/amdgpu-pro/lib64 since it is needed only for my system
On Tue, 06.06.17 11:48, Germano Massullo (germano.massullo@gmail.com) wrote:
Hi there, I am the co-maintainer of boinc-client [1]. boinc-client runs as a service, and both it and its working units run as 'boinc' user and they are confined by SELinux. Recently, I investigated to figure out why boinc-client, while running as a service, could not detect videocard for GPU calculus. In order to fix this problem I had to add Group=video to boinc-client systemd unit file. I have not yet pushed such change to boinc-client Fedora git, because I would like to ask you if this can cause a breach into boinc-client confinement. I mean, I am wondering if a process that can have access to videocard, could for example read what you are doing on your machine, the passwords you copy and paste, etc.
The "video" group is pretty broad, it covers video4linux, DRM and related, DVB, even some firewire stuff. Giving a service access to the local display hardware means you possibly grant access to reading backing the screen contents, and giving a service access to the v4l devices means the service can film the user.
Note sure what "boinc-client" does, but if this isn't turstworthy then it probably shouldn't be able to get access to "video".
ExecStopPost=/bin/rm -f /var/lib/boinc/lockfile
If this file is not supposed to survive a daemon restart it really should be placed in /run somewhere.
Group=video
I don't know your package, but I have the suspicion you should better use SupplementaryGroups=video than Group=, as the latter chooses the group your service creates files as, and the former only grants access to additional resources.
But then again, you probably shouldn't do all this at all, unless your service shall be able to film your users.
Lennart
2017-06-06 14:40 GMT+02:00 Lennart Poettering mzerqung@0pointer.de:
Note sure what "boinc-client" does, but if this isn't turstworthy then it probably shouldn't be able to get access to "video".
boinc-client is the client side version of BOINC (Berkeley Open Infrastructure for Network Computing). You can use your computers to help scientific research of many different projects. You can think about it as a music player, the projects as the music discs, and the working units as disc tracks. Since working units are closed source software we always considered them not trustworthy, therefore they always runned confined as much as possible
ExecStopPost=/bin/rm -f /var/lib/boinc/lockfile
If this file is not supposed to survive a daemon restart it really should be placed in /run somewhere.
I will take care of this.
Group=video
I have the suspicion you should better use SupplementaryGroups=video than Group=, [...]
I will not use any of them, as soon as possible I will start investigating on using udev/ACLs on dri/render to solve the GPU detection problem.
Thank you for clarifing my dubts Lennart Have a nice day!
On Tue, 06.06.17 17:44, Germano Massullo (germano.massullo@gmail.com) wrote:
2017-06-06 14:40 GMT+02:00 Lennart Poettering mzerqung@0pointer.de:
Note sure what "boinc-client" does, but if this isn't turstworthy then it probably shouldn't be able to get access to "video".
boinc-client is the client side version of BOINC (Berkeley Open Infrastructure for Network Computing). You can use your computers to help scientific research of many different projects. You can think about it as a music player, the projects as the music discs, and the working units as disc tracks. Since working units are closed source software we always considered them not trustworthy, therefore they always runned confined as much as possible
If so, this sounds like a great candidate for using systemd's sandboxing functionality. Things like CapabilityBoundingSet=, PrivateTmp=, ProtectSystem=, ProtectHome=, ProtectKernelTunables=, ProtectKernelModules=, ProtectControlGroup=, SystemCallFilter=, SystemCallArchitectures=, RestrictAddressFamilies=, RestrictNamespaces=, RestrictRealtime=, ...
See systemd.exec(5) for more information.
Lennart
Il 07/06/2017 09:22, Lennart Poettering ha scritto:
On Tue, 06.06.17 17:44, Germano Massullo (germano.massullo@gmail.com) wrote:
2017-06-06 14:40 GMT+02:00 Lennart Poettering mzerqung@0pointer.de:
Note sure what "boinc-client" does, but if this isn't turstworthy then it probably shouldn't be able to get access to "video".
boinc-client is the client side version of BOINC (Berkeley Open Infrastructure for Network Computing). You can use your computers to help scientific research of many different projects. You can think about it as a music player, the projects as the music discs, and the working units as disc tracks. Since working units are closed source software we always considered them not trustworthy, therefore they always runned confined as much as possible
If so, this sounds like a great candidate for using systemd's sandboxing functionality. Things like CapabilityBoundingSet=, PrivateTmp=, ProtectSystem=, ProtectHome=, ProtectKernelTunables=, ProtectKernelModules=, ProtectControlGroup=, SystemCallFilter=, SystemCallArchitectures=, RestrictAddressFamilies=, RestrictNamespaces=, RestrictRealtime=, ...
See systemd.exec(5) for more information.
Lennart
Thank you, I will consider systemd sandboxing too
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Lennart Poettering