On Sun, Oct 06, 2019 at 12:01:25PM +0200, Dominick Grift wrote: > On Sun, Oct 06, 2019 at 11:41:56AM +0200, Dominick Grift wrote: > > 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/$(id -u gdm) > > Just to clarify. The patch you reference is not responsible for the uglyness that is GDM/Gnome > Without this patch, the systemd --user instance of GDM (and any other users) would run in "init_t". This is obviously also not desirable. I wonder what you happen if you would (would gdm still work?): sudo systemctl mask user@$(id -u gdm).service user-runtime-dir@$(id -u gdm).service > > > > > > > > > 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 > > > > -- > Key fingerprint = 5F4D 3CDB D3F8 3652 FBD8 02D5 3B6C 5F1D 2C7B 6B02 > https://sks-keyservers.net/pks/lookup?op=get&search=0x3B6C5F1D2C7B6B02 > Dominick Grift -- 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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