[ GLSA 200709-11 ] GDM: Local Denial of Service

[GLSA]

Gentoo Linux Security Advisory

Title: GDM: Local Denial of Service (GLSA 200709-11)
Severity: low
Exploitable: local
Date: September 18, 2007
Bug(s): #187919
ID: 200709-11

Synopsis

GDM can be crashed by a local user, preventing it from managing future displays.

Background

GDM is the GNOME display manager.

Affected Packages

Package: gnome-base/gdm
Vulnerable: < 2.18.4
Unaffected: >= 2.18.4
Unaffected: >= 2.16.7 < 2.16.8
Architectures: All supported architectures


Description

The result of a g_strsplit() call is incorrectly parsed in the files daemon/gdm.c, daemon/gdmconfig.c, gui/gdmconfig.c and gui/gdmflexiserver.c, allowing for a null pointer dereference.

Impact

A local user could send a crafted message to /tmp/.gdm_socket that would trigger the null pointer dereference and crash GDM, thus preventing it from managing future displays.

Workaround

Restrict the write permissions on /tmp/.gdm_socket to trusted users only after each GDM restart.

Resolution

All GDM users should upgrade to the latest version: