Created attachment 1297141 [details] logs Description of problem: GDM fails to start when SELinux default user is mapped to the guest_u user on Fedora 26. The following error message is shown in the console: Failed to start User Manager for UID 42 UID 42 is gdm: getent passwd | grep 42 gdm:x:42:42::/var/lib/gdm:/sbin/nologin On Fedora 25 GDM starts without any problems when SELinux default user mapped is to guest_u user. Version-Release number of selected component (if applicable): gdm-3.24.2-1.fc26.x86_64 Some other component versions: pam-1.3.0-2.fc26.x86_64 selinux-policy-targeted-3.13.1-259.fc26.noarch systemd-pam-233-6.fc26.x86_64 systemd-libs-233-6.fc26.x86_64 How reproducible: Always. Steps to Reproduce: 1. Install Fedora 26 Workstation with default settings. 2. Change mapping of default SELinux user to guest_u with the following command: semanage login -m -s guest_u __default__ 3. Reboot the computer Actual results: Computer boot stops in text mode. The following error message is show: Failed to start User Manager for UID 42 Expected results: Computer booting to GNOME login screen. Additional info: It looks like gdm is started with guest_r role and this role is picked because SELinux default user is mapped to guest_u. SELinux default user should not be used for services. See attachment for journalctl and AVCs output.
Got this problem while upgrading from 25 with DNF system-upgrade plugin. Is it possible to fix it via specifying SELinux settings for GDM manually?
This also appears to be a problem when the default user is user_u.
I also have this issue. It seems to be temporarily fixed by first logging in as the xguest user without a desktop environment, then logging in with the desktop environment. So long as the xguest user is already logged in, selinux seems to allow the user to log in with GDM as well.
This message is a reminder that Fedora 26 is nearing its end of life. Approximately 4 (four) weeks from now Fedora will stop maintaining and issuing updates for Fedora 26. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '26'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 26 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
Fedora 26 changed to end-of-life (EOL) status on 2018-05-29. Fedora 26 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.