[apparmor] Bug#735470: Fwd: Bug#735470: Could be implemented centrally with a dpkg trigger instead of requiring every package shipping an apparmor file to use dh_apparmor

[John Johansen]

On 01/16/2014 02:57 PM, John Johansen wrote:
> On 01/16/2014 02:49 PM, Kees Cook wrote:
>> On Thu, Jan 16, 2014 at 07:37:04PM +0100, Didier 'OdyX' Raboud wrote:
>>> Le jeudi, 16 janvier 2014 10.14:14, vous avez écrit :
>>>> On Thu, Jan 16, 2014 at 11:11:22AM +0100, Didier 'OdyX' Raboud wrote:
>>>>> As far as I understand deb-triggers' manpage, this can be enforced
>>>>> using 'activate /etc/apparmor.d/', which will then make the trigger
>>>>> run "at the start of the configure operation", which ensures
>>>>> exactly what you want.
>>>>
>>>> Per-policy reloads must happen before a daemon restarts, so they
>>>> cannot be triggers.
>>>
>>> Err…
>>>
>>> man deb-trigggers contradicts you, in my reading; an 'activate 
>>> /etc/apparmor.d' triggers' file in apparmor would make its action run 
>>> _before_ cups (which would have shipped /etc/apparmor.d/usr.sbin.cupsd) 
>>> would be 'configured' (hence its postinst run).
>>>
>>> Isn't it?
>>
>> Right, sorry, you are right, but my original observation stands: we should
>> never reload all apparmor profiles when installing a single profile. Just
>> the single profile should be reloaded. Otherwise we end up doing very
>> CPU expensive work for no reason. The point of dh-apparmor is to reload a
>> single profile, not all of them. Doing a trigger for all-profile reload
>> isn't something we want. Think of the situation where someone has 5000
>> apache virtual host profiles and they update cups. We never want to wait
>> for those 5000 to be reloaded when cups's profile is installed. Hence,
>> dh_apparmor.
>>
> Is there a way for a trigger to notice which file was updated?
> That way we could use a trigger.
> 
> If not another option that comes to mind is we could add a new flag to the
> parser that would say reload only if the cache is out of date.
> 
> The trigger would have to still do work figuring out which cache files
> are out of date but thats still better than reloading everything to the
> kernel.
> 
by trigger, I mean the parser/script called by the trigger.