[systemd-devel] Antw: Re: systemd's connections to /run/systemd/private ?

[Michael Chapman]

On Wed, 14 Aug 2019, Reindl Harald wrote:
> Am 14.08.19 um 12:41 schrieb Michael Chapman:
> > On Wed, 14 Aug 2019, Reindl Harald wrote:
> >> Am 14.08.19 um 12:10 schrieb Ulrich Windl:
> >>>>>> Michael Chapman <mike at very.puzzling.org> schrieb am 14.08.2019 um 11:47 in
> >>>> That's all true, but the thing we need to check here is that systemd 
> >>>> correctly handles junk on the /run/systemd/private socket. The change on 
> >>>> the systemctl side certainly tries to prevent incorrect data being sent 
> >>>> down the socket -- though it looks like there's several ways in which 
> >>>> fd_move_above_stdio() can fail, so this isn't foolproof -- but we need to 
> >>>> ensure that some _malicious_ client can't DoS systemd.
> >>>
> >>> I don't want to contradict in principle, but doesn't "private socket" mean it's intended to be used by systemd only? Of course being root allows you to use any socket...
> >>
> >> may is ask you to read the thread you are responding to?
> >> nobody is touching the private socket
> > 
> > systemctl will mostly use /run/systemd/private when run as root
> 
> that's not the point - the point is his talking about "doesn't private
> socket mean" when the code triggering in the thread the issue don't talk
> to it directly

I don't know who specifically you are referring to.

Brian's example, when run as root, connects to systemd using the private 
socket. When run as an unprivileged user it will go via the DBus daemon 
instead.