[avahi] Avahi daemon dies on certain hostnames

[Sebastien Estienne]

On 3/21/06, Iván Sánchez Ortega <i.sanchez at mirame.net> wrote:
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> Hi,
>
> I just discovered that the Avahi daemon dies if one machine in the network
> handles out a response with a strange host (or domain) name.
>
> I'm attaching the ethereal capture of the packet that "kills" the avahi
> daemon, but this is how I can reproduce this:
>
> - - Buy an Axis IP camera
> - - Change the camera hostname by issuing the following command:
> wget
> http://{camera_ip_address}/axis-cgi/admin/param.cgi?action=update&Network.Bonjour.FriendlyName=fóobar
> (notice the acute in the 'ó')
> - - Run avahi-browse -at
> - - Watch how the avahi daemon dies.
>
> I guess that setting up any other kind of mDNS responder (an avahi daemon, a
> Bonjour-enabled Mac, etc) to return a hostname with "strange" characters
> (anything not in 7-bit ASCII, I guess, like in "fóobar") may be able to
> reproduce this bug. By the way, I'm running Avahi 0.6.9 here.
>
>
> Running avahi-browse -at in a network with such a device results in the
> following error message:
>
> Client failure, exiting: Daemon connection failed
> 14700: arguments to dbus_connection_get_is_connected() were incorrect,
> assertion "connection != NULL" failed in file dbus-connection.c line 1984.
> This is normally a bug in some application using the D-BUS library.

Are you sure that it's not the dbus daemon that is dying and then
avahi-daemon cleanly exit because no more dbus-daemon is available?

>
> And the following line in /var/log/syslog:
>
> Mar 21 16:23:27 localhost avahi-daemon[14700]: Disconnnected from D-BUS,
> terminating...
this message happens when the dbus-daemon is stopped, so avahi-daemon
exits cleanly

>
>
>
> Obviously, capable network administrators won't set invalid FQDNs in their
> networks, but I don't like the possibility of an (un)intentionally malformed
> mDNS response packet being able to shut down the avahi daemons in my network.
>
>
>
> P.S.: Should I open a new ticket in the Avahi TRAC with this information?

yes please

>
>
>
> Best regards,
> - - --
> - - ----------------------------------
> Iván Sánchez Ortega <ivansanchez at escomposlinux.org> <i.sanchez at mirame.net>
>
> Now listening to: Underworld - Café Del Mar: Volumen Uno - [8] Second Hand
> (9:01) (94%)
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--
Sebastien Estienne