[Pkg-utopia-maintainers] Bug#507815: consolekit: race condition during D-Bus activation

[Fabian Knittel]

Package: consolekit
Version: 0.2.10-2
Severity: normal

Hello,

on a system where ConsoleKit is only used sporadically, a race condition
caused by the interaction between D-Bus' activation code and
console-kit-daemon's backgrounding has surfaced.

If console-kit-daemon backgrounds quickly enough that the D-Bus code hasn't
returned to the caller yet, the caller receives the error "Launch helper
exited with unknown return code 0".

This can be demonstrated by the attached python script.

  $ sudo killall /usr/sbin/console-kit-daemon
  $ ./test-ck
  Unable to use PackageKit: org.freedesktop.DBus.Error.Spawn.ChildExited:
  Launch helper exited with unknown return code 0

(You might need to repeat the above steps a few times to reproduce.)

To avoid the race condition, the following change simply disables the
backgrounding in console-kit-daemon for the D-Bus activation case:

--- /usr/share/dbus-1/system-services/org.freedesktop.ConsoleKit.service 2008-12-04 18:17:43.000000000 +0100
+++ /usr/share/dbus-1/system-services/org.freedesktop.ConsoleKit.service 2008-12-04 18:17:34.000000000 +0100
@@ -1,4 +1,4 @@
 [D-BUS Service]
 Name=org.freedesktop.ConsoleKit
-Exec=/usr/sbin/console-kit-daemon
+Exec=/usr/sbin/console-kit-daemon --no-daemon
 User=root

The alternative would be to fix D-Bus to assume return code 0 is fine, as long
as someone continues to provide the requested service. So maybe this is a bug
in D-Bus and not in ConsoleKit.

Cheers, Fabian

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing'), (100, 'unstable'), (1, 'experimental')
Architecture: i386 (x86_64)

Kernel: Linux 2.6.18-6-xen-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages consolekit depends on:
ii  dbus                   1.2.1-4           simple interprocess messaging syst
ii  libc6                  2.7-16            GNU C Library: Shared libraries
ii  libck-connector0       0.2.10-2          ConsoleKit libraries
ii  libdbus-1-3            1.2.1-4           simple interprocess messaging syst
ii  libdbus-glib-1-2       0.76-1            simple interprocess messaging syst
ii  libglib2.0-0           2.16.6-1          The GLib library of C routines
ii  libx11-6               2:1.1.5-2         X11 client-side library
ii  zlib1g                 1:1.2.3.3.dfsg-12 compression library - runtime

Versions of packages consolekit recommends:
pn  libpam-ck-connector           <none>     (no description available)

consolekit suggests no packages.

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