Re: [AppArmor 39/41] AppArmor: Profile loading and manipulation, pathname matching

Alan Cox
2007-04-16T21:57:31Z

> don't actually have to care --- if loading an invalid profile can bring down
> the system, then that's no worse than an arbitrary module that crashes the
> machine. Not sure if there will ever be user loadable profiles; at least at
> that point we had to care.

CAP_SYS_RAWIO is needed to do arbitary patching/loading in the capability
model so if you are using lesser capabilities it is a (minor) capability
rise but not a big problem, just ugly and wanting a fix

> > > + /*
> > > + * Replacement needs to allocate a new aa_task_context for each
> > > + * task confined by old_profile. To do this the profile locks
> > > + * are only held when the actual switch is done per task. While
> > > + * looping to allocate a new aa_task_context the old_task list
> > > + * may get shorter if tasks exit/change their profile but will
> > > + * not get longer as new task will not use old_profile detecting
> > > + * that is stale.
> > > + */
> > > + do {
> > > + new_cxt = aa_alloc_task_context(GFP_KERNEL | __GFP_NOFAIL);
> >
> > NOFAIL is usually a bad sign. It should be only used if there is no
> > alternative.
>
> At this point there is no secure alternative to allocating a task context ---
> except killing the task, maybe.

Can you count the number needed, preallocate them and then when you know
for sure either succeed or fail the operation as a whole ?