Henne Vogelsang discovered that, as of glib 2.28, it was possible to run the default web browser (usually Firefox) in the GDM session, as the gdm user. This resulted in uncontrolled access to the local file system and possibly other resources as the gdm user. This is because glib 2.28 has changed the way URI handlers are registered; while it used to be controlled via gconf settings, it now is controlled via x-scheme-handler/<scheme> mime types (e.g. x-scheme-handler/http). Statement: Not vulnerable. This issue did not affect the versions of gdm as shipped with Red Hat Enterprise Linux 4, 5, or 6.
Created attachment 501874 [details] upstream patch
This issue only affects Fedora 15; earlier releases of Fedora and Red Hat Enterprise Linux still use the old gconf-based URI-handling method that is not vulnerable to this flaw.
Public now via: http://git.gnome.org/browse/gdm/commit/?id=d13dd72531599ab7e4c747db3b58a8c17753e08d This fix adds a custom MIME configuration for the gdm user to ensure no default URI scheme handler is used to work around the change in glib.
Created gdm tracking bugs for this issue Affects: fedora-15 [bug 709508]