[avahi] Avahi daemon dies on certain hostnames

[Iván Sánchez Ortega]

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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.

And the following line in /var/log/syslog:

Mar 21 16:23:27 localhost avahi-daemon[14700]: Disconnnected from D-BUS, 
terminating...



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?



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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