Bug#458141: gdm: user Xauthority not deleted on logout if permissions/group changed

[Daniel Dickinson]

Package: gdm
Version: 2.16.4-1
Severity: normal


I have a user with home directory /home/user and am using a sudo sandbox 
for applications such as iceweasel.  In order to make that work it is 
necessary to change the permissions on /home/user/.Xauthority to group 
readable and the group to a group created to allow access to the 
..Xauthority file by the iceweasel-user user.  The difficulty arises when 
I logout and login again (to a gnome desktop).  In that case the 
..Xauthority file is no longer used and a new one under /tmp is created 
and used in the XAUTHORITY environment variable.  Before I realize 
this I was using a hardcoded /home/user/.Xauthority in the changing 
permissions script, which meant xuser never got permission to use the 
new XAUTHORITY file and therefore iceweasel refused to start (via sudo 
-u iceweasel-user iceweasel).  If I manually deleted the 
/home/user/.Xauthority before I logged out things worked as expected.

It may also matter that I am using a dual-headed display.

-- System Information:
Debian Release: 4.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-5-686
Locale: LANG=en_CA.UTF-8, LC_CTYPE=en_CA.UTF-8 (charmap=UTF-8)

Versions of packages gdm depends on:
ii  adduser                3.102             Add and remove users and groups
ii  debconf [debconf-2.0]  1.5.11etch1       Debian configuration management sy
ii  gksu                   2.0.0-1           graphical frontend to su
ii  gnome-session          2.14.3-5          The GNOME 2 Session Manager
ii  gnome-terminal [x-term 2.14.2-1          The GNOME 2 terminal emulator appl
ii  libart-2.0-2           2.3.17-1          Library of functions for 2D graphi
ii  libatk1.0-0            1.12.4-3          The ATK accessibility toolkit
ii  libattr1               2.4.32-1          Extended attribute shared library
ii  libc6                  2.3.6.ds1-13etch4 GNU C Library: Shared libraries
ii  libcairo2              1.2.4-4           The Cairo 2D vector graphics libra
ii  libdmx1                1:1.0.2-2         X11 Distributed Multihead extensio
ii  libfontconfig1         2.4.2-1.2         generic font configuration library
ii  libglade2-0            1:2.6.0-4         library to load .glade files at ru
ii  libglib2.0-0           2.12.4-2          The GLib library of C routines
ii  libgnomecanvas2-0      2.14.0-2          A powerful object-oriented display
ii  libgtk2.0-0            2.8.20-7          The GTK+ graphical user interface 
ii  libpam-modules         0.79-5            Pluggable Authentication Modules f
ii  libpam-runtime         0.79-5            Runtime support for the PAM librar
ii  libpam0g               0.79-5            Pluggable Authentication Modules l
ii  libpango1.0-0          1.14.8-5          Layout and rendering of internatio
ii  libpopt0               1.10-3            lib for parsing cmdline parameters
ii  librsvg2-2             2.14.4-3          SAX-based renderer library for SVG
ii  librsvg2-common        2.14.4-3          SAX-based renderer library for SVG
ii  libselinux1            1.32-3            SELinux shared libraries
ii  libwrap0               7.6.dbs-13        Wietse Venema's TCP wrappers libra
ii  libx11-6               2:1.0.3-7         X11 client-side library
ii  libxau6                1:1.0.1-2         X11 authorisation library
ii  libxcursor1            1.1.7-4           X cursor management library
ii  libxdmcp6              1:1.0.1-2         X11 Display Manager Control Protoc
ii  libxext6               1:1.0.1-2         X11 miscellaneous extension librar
ii  libxfixes3             1:4.0.1-5         X11 miscellaneous 'fixes' extensio
ii  libxi6                 1:1.0.1-4         X11 Input extension library
ii  libxinerama1           1:1.0.1-4.1       X11 Xinerama extension library
ii  libxml2                2.6.27.dfsg-1     GNOME XML library
ii  libxrandr2             2:1.1.0.2-5       X11 RandR extension library
ii  libxrender1            1:0.9.1-3         X Rendering Extension client libra
ii  lsb-base               3.1-23.2etch1     Linux Standard Base 3.1 init scrip
ii  metacity [x-window-man 1:2.14.5-4        A lightweight GTK2 based Window Ma
ii  twm [x-window-manager] 1:1.0.1-4         Tab window manager
ii  xbase-clients          1:7.1.ds1-2       miscellaneous X clients
ii  xterm [x-terminal-emul 222-1etch2        X terminal emulator

Versions of packages gdm recommends:
pn  gdm-themes                    <none>     (no description available)
ii  whiptail                      0.52.2-10  Displays user-friendly dialog boxe
ii  zenity                        2.14.3-1   Display graphical dialog boxes fro

-- debconf information:
  gdm/daemon_name: /usr/bin/gdm
* shared/default-x-display-manager: gdm