Re: X session and hostname changing policy

[Fırat Birlik <fbirlik gmail com>]

2010/6/17 Dan Williams <dcbw redhat com>:
> On Mon, 2010-06-14 at 23:16 +0300, Fırat Birlik wrote:
>> Hi there,
>>
>> I experience a problem with hostname manipulation of NetworkManager
>> and the X session.  DHCP server sends a hostname within the dhcp
>> offer, which is different the current one.  There is no persistent
>> hostname definition within the 'nm-system-settings.conf' as this is a
>> default installation.  NetworkManager just changes the hostname and as
>> new hostname is not authenticated (xhost cookie MIT-MAGIC-COOKIE-1 for
>> new hostname does not exist) no new application can be started
>> afterwards.
>
> The solution is *not* to use hostname for local X authentication at all.
> Instead, you want to allow all connections via Unix sockets from the
> session user, which means that your X init should be doing something
> like this:
>
> [ -x /usr/bin/xhost ] && [ -x /usr/bin/id ] &&
>    xhost +si:localuser:`id -un` >& /dev/null
>
> which normally goes in 'localuser.sh' in /etc/X11/xinit/xinitrc.d or
> wherever scripts get executed during X init time.  Hostnames do change
> and relying on it for something like local authentication will certainly
> break stuff.
>

Thanks for pointing that out, I think this is the solution for major
part of the problem, instead of forcing a persistent hostname.

But there is also SESSION_MANAGER variable and xauth list, because
both depend on the previous hostname.  Do you have any tips for these
also?

Firat

> Most distros have had this fixed for a while now.
>
> Dan
>
>> To avoid this behavior, I can define a persistent hostname equal the
>> content of /etc/HOSTNAME (this is a slackware system) as the
>> following:
>>
>> --- /etc/NetworkManager/nm-system-settings.conf~
>> +++ /etc/NetworkManager/nm-system-settings.conf
>> @@ -1,2 +1,5 @@
>>  [main]
>>  plugins=keyfile
>> +
>> +[keyfile]
>> +hostname=myhostname
>>
>>
>> As persistent hostname has highest precedence, problem looks solved;
>> but this should be repeated for each installation.
>>
>> What I'm asking is, is there any config option or some way to not let
>> NetworkManager change the hostname?
>>
>> As a note, current precedence order for hostname (taken from
>> NetworkManagerPolicy.c):
>>
>>        * 1) a configured hostname (from system-settings)
>>        * 2) automatic hostname from the default device's config (DHCP, VPN, etc)
>>        * 3) the original hostname when NM started
>>        * 4) reverse-DNS of the best device's IPv4 address
>>
>>
>> Thanks,
>>
>> Firat
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>
>
>