Red Hat Bugzilla – Bug 469389
Any user can send dbus messages to gdm that start a new X session
Last modified: 2015-01-14 18:21:57 EST
Any local user can call CreateTransientDisplay on the org.gnome.DisplayManager.LocalDisplayFactory interface which results in a new X session. Beyond that this will annoy the hell out of whoever is on the local machine I suspect that a loop that keeps sending the message can be an effective DOS.
Created attachment 322103 [details] example "exploit"
So at a minimum we should modify the dbus security policy in /etc/dbus-1/system.d to only allow at_console users to run it, but really we should be using policykit to levy access.
Is this interface used to spawn another local session when some user is already logged-in in X? If so, restricting this to console users only sounds good. I'm not sure how PolicyKit is expected to be used here.
I at least have no idea at all as to what is using this interface. Probably just fast user switching but you never know. I am not sure that I want my users to be able to start an unlimited amount of X servers even if they are in the console to tell the truth but this is a different story I guess.
This bug appears to have been reported against 'rawhide' during the Fedora 10 development cycle. Changing version to '10'. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
This message is a reminder that Fedora 10 is nearing its end of life. Approximately 30 (thirty) days from now Fedora will stop maintaining and issuing updates for Fedora 10. It is Fedora's policy to close all bug reports from releases that are no longer maintained.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 WONTFIX if it remains open with a Fedora 'version' of '10'. 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 prior to Fedora 10's end of life. Bug Reporter: Thank you for reporting this issue and we are sorry that we may not be able to fix it before Fedora 10 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 please change the 'version' of this bug to the applicable version. If you are unable to change the version, please add a comment here and someone will do it for you. 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. The process we are following is described here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
Fedora 10 changed to end-of-life (EOL) status on 2009-12-17. Fedora 10 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. Thank you for reporting this bug and we are sorry it could not be fixed.