[apparmor] AppArmor and ntpd

Martin Burnicki martin.burnicki at meinberg.de
Mon Dec 6 16:38:22 GMT 2010


Steve Beattie wrote:
[...]
> Right, as was pointed out in
> https://bugzilla.novell.com/show_bug.cgi?id=230700#c12 To expand on
> the comment, though, the tunable variables can hold multiple values,
> such that defining:
> 
>   @{NTPD_DEVICE}="/dev/tty10" /dev/mbgclock* /dev/some_other_mfctr_devices*
> 
> will cause
> 
>   @{NTPD_DEVICE} rw,
> 
> to allow read and write access to all three sets of devices.

That's an interesting way to get this working.

> I think the important question that Martin is asking whether we
> think it's appropriate to include /dev/mbgclock* in the default
> tunable field in the distributed profile set.

I've not really been asking to include /dev/mbgclock* as a default. Just
wanted to be sure it can easily be added. Anyway, if it can become one
of the defaults it's even better.

> IMO, considering that
> it's a much more specialized device path than /dev/ttyS*, which the
> original referenced bugzilla report was asking about, I think it's
> a reasonable thing to include, as well as documentation explaining
> how to add additional devices to the tunable.
> 
> As an aside, looking at what our existing ntpd tunable has, we already
> allow /dev/tty10. It looks like it got added in response to novell
> bugzilla bugs 433368 or 402693, which I'm not privileged enough
> to view.  Christian, do you have access to those bugs to clarify the
> justification for it? I really don't like it as a default, though I'll
> admit it's far less likely that /dev/tty10 will be used by anything
> else, unlike /dev/ttyS*.

I also find it strange to include one single dedicated serial port as
default.

Maybe it could be better to use /dev/refclock-* as a default. These are
usually symlinks used by ntpd's parse driver which point to real
/dev/ttyS* devices, if used by ntpd, and even if /dev/mbgclock* is used
by ntpd it is accesssed via a /dev/refclock-* symlink.

Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany



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