Launchpad has imported 4 comments from the remote bug at https://bugzilla.redhat.com/show_bug.cgi?id=1745147.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2019-08-23T17:40:00+00:00 sfroemer wrote: Description of problem: A user with login-shell set to /sbin/nologin is still able to login using GDM Version-Release number of selected component (if applicable): gdm-3.28.3-20.el8.x86_64 How reproducible: 100% Steps to Reproduce: 1. RHEL 8 2. useradd -s /sbin/nologin -m user2 3. login via GDM Actual results: The user is able to login Expected results: The user should not be able to login Additional info: # grep user2 /etc/passwd user2:x:1001:1001::/home/user2:/sbin/nologin # w 17:39:27 up 30 min, 2 users, load average: 0,80, 0,17, 0,07 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root pts/0 172.16.100.100 17:09 1.00s 0.11s 0.01s w user2 :1 :1 17:39 ?xdm? 16.42s 0.02s /usr/libexec/gdm-x-session gnome-session # su - user2 Last login: Fr Aug 23 17:39:24 UTC 2019 on tty2 This account is currently not available. Reply at: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2039354/comments/0 ------------------------------------------------------------------------ On 2019-09-13T03:33:44+00:00 dchen wrote: I can reproduce it with gdm-3.28-3-20.el8.x86_64 Reply at: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2039354/comments/1 ------------------------------------------------------------------------ On 2019-10-21T14:30:52+00:00 rstrode wrote: So this is an interesting bug. For console logins, they get the lock out for "free", because they're just handing off to the shell which is /sbin/nologin. For graphical logins, we're starting a graphical desktop, not the users shell. We do still run a shell, however, as part of the login process. /usr/bin/gnome-session is a shell script that does: if [ "x$XDG_SESSION_TYPE" = "xwayland" ] && [ "x$XDG_SESSION_CLASS" != "xgreeter" ] && [ -n "$SHELL" ] && grep -q "$SHELL" /etc/shells && ! (echo "$SHELL" | grep -q "false") && ! (echo "$SHELL" | grep -q "nologin"); then if [ "$1" != '-l' ]; then exec bash -c "exec -l '$SHELL' -c '$0 -l $*'" else shift fi fi See it runs exec -l '$SHELL' to execute the users shell as a "login shell" so all the appropriate startup scripts get run. But also see it explicitly avoids this step for the "nologin" shell. The reasoning for this is discussed upstream here: https://bugzilla.gnome.org/show_bug.cgi?id=736660#c58 Namely, the login screen itself uses gnome-session and has its shell set to nologin! But i think we're still safe to remove the check because we also check XDG_SESSION_CLASS to make sure it's not a login screen before proceeding. In other words, we had redundant checks to skip the script loading for the login screen and dropping one shouldn't hurt anything. Dropping it, will mean that we try to run nologin as the users shell during login. it will fail and login will be aborted which is the desired behavior. devack+ Reply at: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2039354/comments/2 ------------------------------------------------------------------------ On 2020-04-28T16:09:41+00:00 errata-xmlrpc wrote: Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2020:1766 Reply at: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2039354/comments/3 ** Changed in: gdm3 (Fedora) Status: Unknown => Fix Released ** Changed in: gdm3 (Fedora) Importance: Unknown => High ** Bug watch added: bugzilla.gnome.org/ #736660 https://bugzilla.gnome.org/show_bug.cgi?id=736660 -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gdm3 in Ubuntu. https://bugs.launchpad.net/bugs/2039354 Title: GDM does not prevent users with login shell /sbin/nologin from logging on To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/2039354/+subscriptions -- desktop-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
