Bug#289641: gdm: Broken local X server disables xdmcp

[Roland Turner]

Package: gdm
Version: 2.6.0.6-1
Severity: normal

I'm not clear on why this is happening (no clues in logs), but
when the local X server keeps crashing (e.g. on a machine in a
locked room that no-one ever visits and will therefore not see
the helpful error message on the console), gdm not only disables
the starting of a session on the console, but also disables xdmcp
clients. From tethereal:

  0.000000 192.168.0.3 -> 192.168.0.255 XDMCP Broadcast_query
  2.009999 192.168.0.3 -> 192.168.0.255 XDMCP Broadcast_query
  3.535551 192.168.0.3 -> 192.168.0.1 XDMCP Query
  4.009875 192.168.0.3 -> 192.168.0.255 XDMCP Broadcast_query
  4.009898 192.168.0.3 -> 192.168.0.1 XDMCP Query

The reason for the failure to respond to queries is not logged.
Commenting out "0=Standard" in the [servers] section of gdm.conf
and restarting gdm immediately resolves the problem:

382.061415 192.168.0.3 -> 192.168.0.1 XDMCP Query
382.128748 192.168.0.1 -> 192.168.0.3 XDMCP Willing
386.264859 192.168.0.3 -> 192.168.0.1 XDMCP Query
386.265170 192.168.0.1 -> 192.168.0.3 XDMCP Willing
389.029627 192.168.0.3 -> 192.168.0.1 XDMCP Request
389.030300 192.168.0.1 -> 192.168.0.3 XDMCP Accept
389.030464 192.168.0.3 -> 192.168.0.1 XDMCP Manage

XDMCP should work independently of the local X server.

- Raz

-- System Information:
Debian Release: 3.1
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.4.27-1-686-smp
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages gdm depends on:
ii  adduser              3.59                Add and remove users and groups
ii  debconf              1.4.30.11           Debian configuration management sy
ii  dpkg                 1.10.25             Package maintenance system for Deb
ii  gksu                 1.2.2-1             graphical frontend to su
ii  gnome-session        2.8.1-4             The GNOME 2 Session Manager
ii  gnome-terminal [x-te 2.8.0-2             The GNOME 2 terminal emulator appl
ii  libart-2.0-2         2.3.16-6            Library of functions for 2D graphi
ii  libatk1.0-0          1.8.0-4             The ATK accessibility toolkit
ii  libattr1             2.4.16-1            Extended attribute shared library
ii  libaudiofile0        0.2.6-5             Open-source version of SGI's audio
ii  libbonobo2-0         2.8.0-4             Bonobo CORBA interfaces library
ii  libbonoboui2-0       2.8.0-2             The Bonobo UI library
ii  libbz2-1.0           1.0.2-1             A high-quality block-sorting file 
ii  libc6                2.3.2.ds1-20        GNU C Library: Shared libraries an
ii  libcroco3            0.6.0-2             a generic Cascading Style Sheet (C
ii  libesd0              0.2.35-2            Enlightened Sound Daemon - Shared 
ii  libgconf2-4          2.8.1-4             GNOME configuration database syste
ii  libgcrypt11          1.2.0-4             LGPL Crypto library - runtime libr
ii  libglade2-0          1:2.4.1-1           Library to load .glade files at ru
ii  libglib2.0-0         2.4.8-1             The GLib library of C routines
ii  libgnome-keyring0    0.4.0-2             GNOME keyring services library
ii  libgnome2-0          2.8.0-6             The GNOME 2 library - runtime file
ii  libgnomecanvas2-0    2.8.0-1             A powerful object-oriented display
ii  libgnomeui-0         2.8.0-3             The GNOME 2 libraries (User Interf
ii  libgnomevfs2-0       2.8.3-7             The GNOME virtual file-system libr
ii  libgnutls11          1.0.16-9            GNU TLS library - runtime library
ii  libgpg-error0        1.0-1               library for common error values an
ii  libgsf-1             1.11.1-1            Structured File Library - runtime 
ii  libgtk2.0-0          2.4.14-2            The GTK+ graphical user interface 
ii  libice6              4.3.0.dfsg.1-8      Inter-Client Exchange library
ii  libjpeg62            6b-9                The Independent JPEG Group's JPEG 
ii  liborbit2            1:2.10.2-1.1        libraries for ORBit2 - a CORBA ORB
ii  libpam-modules       0.76-22             Pluggable Authentication Modules f
ii  libpam-runtime       0.76-22             Runtime support for the PAM librar
ii  libpam0g             0.76-22             Pluggable Authentication Modules l
ii  libpango1.0-0        1.6.0-3             Layout and rendering of internatio
ii  libpopt0             1.7-5               lib for parsing cmdline parameters
ii  librsvg2-2           2.8.1-2             SAX-based renderer library for SVG
ii  libselinux1          1.18-3              SELinux shared libraries
ii  libsm6               4.3.0.dfsg.1-8      X Window System Session Management
ii  libtasn1-2           0.2.10-3            Manage ASN.1 structures (runtime)
ii  libwrap0             7.6.dbs-6           Wietse Venema's TCP wrappers libra
ii  libx11-6             4.3.0.dfsg.1-8      X Window System protocol client li
ii  libxext6             4.3.0.dfsg.1-8      X Window System miscellaneous exte
ii  libxml2              2.6.11-5            GNOME XML library
ii  metacity [x-window-m 1:2.8.6-1           A lightweight GTK2 based Window Ma
ii  sawfish [x-window-ma 1:1.3+cvs20040617-7 A window manager for X11
ii  xbase-clients        4.3.0.dfsg.1-8      miscellaneous X clients
ii  xfwm4 [x-window-mana 4.0.6-1             window manager of the XFce project
ii  xlibs                4.3.0.dfsg.1-8      X Window System client libraries m
ii  xterm [x-terminal-em 4.3.0.dfsg.1-8      X terminal emulator
ii  zlib1g               1:1.2.2-3           compression library - runtime

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