[nsd-users] NSD still shows permission errors on Debian 10 Buster

[Anand Buddhdev]

On 27/05/2020 19:02, Simon Deziel wrote:

Hi Simon,

>> Are you certain of this? I have never seen any errors on my NSD systems.
> 
> I reproduced it all in a Debian Buster VM before posting. Are you using
> the same systemd unit as Debian Buster's [*] ?

No, I'm running NSD on CentOS 7. I'm not using the unit file from 
contrib. I find it a mess. It's trying to enable every possible option 
in systemd, without taking care of all the related permission problems 
they cause. I build my own packages of NSD, and ship a very simple unit 
file with it:

[Unit]
Description=NSD DNS Server
After=network-online.target

[Service]
LimitNOFILE=8192
ExecStart=/usr/sbin/nsd -d
KillMode=process

[Install]
WantedBy=multi-user.target

>>> [Service]
>>> ExecStartPre=-/bin/chown --quiet root:root /var/log/nsd.log
>>
>> All of this seems to be band-aid upon band-aid of unnecessary hacks.
> 
> That's a band-aid indeed. IMHO the proper fix is to be consistent in
> handling the file. So either open it as root and not chown it or always
> touch it after setuid().

I agree. In order to avoid problems, on my systems, I log to 
/var/log/nsd, where that directory is owned by nsd:nsd.

>>> As for the failed unlinking of the pidfile, this is harmless and should
>>> not be logged as a warning. It may already be fixed in newer releases as
>>> it was done with Unbound already.
>>
>> PID files are so passé! They are irrelevant on systems where daemons are
>> run under supervisors. I would highly recommend setting "pidfile" to ""
>> in nsd.conf. This prevents creation of a PID file. Systemd already knows
>> the PID of the NSD process, and can signal it directly.
> 
> Would it make sense to simply ignore the pidfile directive when running
> through systemd?

No. I don't like it when software silently does things. Instead, when 
package maintainers build NSD for systems with systemd, they should pass 
the --with-pidfile="" option to the configure script, so that by 
default, NSD doesn't create PID files. If a user still wants a PID file 
for some bizarre reason, he can set the "pidfile" option in nsd.conf. 
And then deal with the permissions issues himself.

Regards,
Anand