Bug#555624: network-manager: pppd connections get killed (dbus communication problem)

[Christoph Haas]

Package: network-manager
Version: 0.7.1-2
Severity: normal

After I create a PPP connection (UMTS here) the connection gets killed
approximately 12 seconds after being established. The syslog showed:

NetworkManager: <WARN> pppd_timed_out(): Looks like pppd didn't initialize our dbus module

Apparently dbus couldn't talk to the Network Manager somehow. I found
a workaround in Ubuntu's bug report #371281 (reply #3) by removing
the "deny" sections from /etc/dbus-1/system.d/NetworkManager.conf.

-- System Information:
Debian Release: squeeze/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 2.6.30-2-686 (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/dash

Versions of packages network-manager depends on:
ii adduser 3.111 add and remove users and groups
ii dbus 1.2.16-2 simple interprocess messaging syst
ii dhcp3-client 3.1.2p1-2 DHCP client
ii hal 0.5.13-3 Hardware Abstraction Layer
ii ifupdown 0.6.9 high level tools to configure netw
ii libc6 2.10.1-5 GNU C Library: Shared libraries
ii libdbus-1-3 1.2.16-2 simple interprocess messaging syst
ii libdbus-glib-1-2 0.82-2 simple interprocess messaging syst
ii libgcrypt11 1.4.4-4 LGPL Crypto library - runtime libr
ii libglib2.0-0 2.22.2-2 The GLib library of C routines
ii libgnutls26 2.8.4-2 the GNU TLS library - runtime libr
ii libgpg-error0 1.6-1 library for common error values an
ii libhal1 0.5.13-3 Hardware Abstraction Layer - share
ii libnl1 1.1-5 library for dealing with netlink s
ii libnm-glib0 0.7.1-2 network management framework (GLib
ii libnm-util1 0.7.1-2 network management framework (shar
ii libpolkit-dbus2 0.9-4 library for accessing PolicyKit vi
ii libpolkit2 0.9-4 library for accessing PolicyKit
ii libtasn1-3 2.3-1 Manage ASN.1 structures (runtime)
ii libudev0 146-5 libudev shared library
ii libuuid1 2.16.1-4 Universally Unique ID library
ii lsb-base 3.2-23 Linux Standard Base 3.2 init scrip
ii wpasupplicant 0.6.9-3 client support for WPA and WPA2 (I
ii zlib1g 1:1.2.3.3.dfsg-15 compression library - runtime

Versions of packages network-manager recommends:
ii dnsmasq-base 2.51-1 A small caching DNS proxy and DHCP
ii iptables 1.4.4-2 administration tools for packet fi
ii network-manager-gnome 0.7.1-1 network management framework (GNOM
ii policykit 0.9-4 framework for managing administrat
ii ppp 2.4.4rel-10.1 Point-to-Point Protocol (PPP) - da

Versions of packages network-manager suggests:
ii avahi-autoipd 0.6.25-1 Avahi IPv4LL network address confi

-- no debconf information

[Michael Biebl]

Post by Christoph Haas
Package: network-manager
Version: 0.7.1-2
Severity: normal

Hi Christoph,

thanks for the bug report.

Post by Christoph Haas
After I create a PPP connection (UMTS here) the connection gets killed
NetworkManager: <WARN> pppd_timed_out(): Looks like pppd didn't initialize our dbus module
Apparently dbus couldn't talk to the Network Manager somehow. I found
a workaround in Ubuntu's bug report #371281 (reply #3) by removing
the "deny" sections from /etc/dbus-1/system.d/NetworkManager.conf.

Were you logged in as root (i.e. is there a file /var/run/console/root) when you
get this failure?
If so, does it make a difference if you logout as root?

Cheers,
Michael

[Christoph Haas]

Thanks for your quick reaction, Michael.

Post by Michael Biebl

Post by Christoph Haas
Package: network-manager
Version: 0.7.1-2
Severity: normal
After I create a PPP connection (UMTS here) the connection gets killed
NetworkManager: <WARN> pppd_timed_out(): Looks like pppd didn't initialize our dbus module
Apparently dbus couldn't talk to the Network Manager somehow. I found
a workaround in Ubuntu's bug report #371281 (reply #3) by removing
the "deny" sections from /etc/dbus-1/system.d/NetworkManager.conf.

Were you logged in as root (i.e. is there a file /var/run/console/root) when you
get this failure?
If so, does it make a difference if you logout as root?

I was logged on in a gnome-terminal and used "su -" to get root privileges
so I could watch the syslog. Now I tried with the original
/etc/dbus-1/system.d/NetworkManager.conf file without having a root
terminal open and the connection gets established properly and stays that way.

What does this mean?

Kind regards
Christoph

[Michael Biebl]

Post by Christoph Haas
Thanks for your quick reaction, Michael.

Post by Michael Biebl

Post by Christoph Haas
Package: network-manager
Version: 0.7.1-2
Severity: normal
After I create a PPP connection (UMTS here) the connection gets killed
NetworkManager: <WARN> pppd_timed_out(): Looks like pppd didn't initialize our dbus module
Apparently dbus couldn't talk to the Network Manager somehow. I found
a workaround in Ubuntu's bug report #371281 (reply #3) by removing
the "deny" sections from /etc/dbus-1/system.d/NetworkManager.conf.

Were you logged in as root (i.e. is there a file /var/run/console/root) when you
get this failure?
If so, does it make a difference if you logout as root?

I was logged on in a gnome-terminal and used "su -" to get root privileges
so I could watch the syslog. Now I tried with the original
/etc/dbus-1/system.d/NetworkManager.conf file without having a root
terminal open and the connection gets established properly and stays that way.
What does this mean?

It's an oddity of the D-Bus policy and the way it is applied.
You first have
<policy user="root">
<allow own="org.freedesktop.NetworkManager"/>
<allow send_destination="org.freedesktop.NetworkManager"/>

<allow send_destination="org.freedesktop.NetworkManager"
send_interface="org.freedesktop.NetworkManager.PPP"/>
</policy>
Which allows to communicate with the PPP service.

A later rule denies that:
<policy at_console="true">
<allow send_destination="org.freedesktop.NetworkManager"/>

<deny send_destination="org.freedesktop.NetworkManager"
send_interface="org.freedesktop.NetworkManager.PPP"/>
</policy>


As you are logged in as user "root", this later deny rule will also be applied
to services running as root, such as the NetworkManager service, if you are not
logged in as user, only the first rule will be applied, and so access is granted.

Cheers,
Michael

[Michael Biebl]

Post by Michael Biebl
It's an oddity of the D-Bus policy and the way it is applied.
You first have
<policy user="root">
<allow own="org.freedesktop.NetworkManager"/>
<allow send_destination="org.freedesktop.NetworkManager"/>
<allow send_destination="org.freedesktop.NetworkManager"
send_interface="org.freedesktop.NetworkManager.PPP"/>
</policy>
Which allows to communicate with the PPP service.

To be more specific: This rule allows the NetworkManager process (running as
root) to communicate with the pppd process (running as root)