On Sun, Oct 06, 2019 at 11:22:00AM +0200, Laurent Bigonville wrote: > Hello, > > I discovered today that the GDM own processes are started as unconfined_t > instead of xdm_t because systemd --user process itself is started in that > context. > > This is probably related to: > > commit da156aea1e89a6ff6025be7e50c9c8173e5a6dcf > Author: Chris PeBenito <Christopher.PeBenito@xxxxxxxxxxxxx> > Date: Fri Apr 19 11:50:59 2019 -0400 > > systemd: Add initial policy for systemd --user. > > This is just a start; it does not cover all uses. > > Signed-off-by: Chris PeBenito <Christopher.PeBenito@xxxxxxxxxxxxx> > > Was that expected and/or wanted? It just means that gdm hooks into pam, and since 1. your __default__ id is set to unconfined_u and 2. you do not have a private id for gdm (and gnome-initial-setup) systemd will start gdm's systemd --user instance with unconfined_u:unconfined_r:unconfined_t. One (ugly but arguable less ugly than the alternative) solution is to create a "xdm_u" and allow systemd to run a systemd --user instance on behalf of gdm with "xdm_u:system_r:xdm_t" That way you can tell selinux that gdm's systemd --user instance should never transition out of xdm_u:system_r:xdm_t echo "system_r:init_t:s0 system_r:xdm_t:s0" > /etc/selinux/TYPE/contexts/users/xdm_u Then all processes in the gdm session should stay in xdm_t (but some processes will be associate with xdm_u and other with system_u). You would probably also want to add to semanage.conf: ignoredirs = /var/lib/gdm;/run/gnome-initial-setup and make sure that selinux does not relabel /run/user/$(id -u gdm) > > Kind regards, > > Laurent Bigonville > -- Key fingerprint = 5F4D 3CDB D3F8 3652 FBD8 02D5 3B6C 5F1D 2C7B 6B02 https://sks-keyservers.net/pks/lookup?op=get&search=0x3B6C5F1D2C7B6B02 Dominick Grift
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