Re: [AppArmor 39/45] AppArmor: Profile loading and manipulation,pathname matching
From: Jack Stone
Date: Thu Jun 14 2007 - 15:17:17 EST
> On Sun, 10 Jun 2007, Pavel Machek wrote:
>> But you have that regex in _user_ space, in a place where policy
>> is loaded into kernel.
> then the kernel is going to have to call out to userspace every time a
> file is created or renamed and the policy is going to be enforced
> incorrectly until userspace finished labeling/relabeling whatever is
> moved. building this sort of race condigion for security into the kernel
> is highly questionable at best.
>> AA has regex parser in _kernel_ space, which is very wrong.
> see Linus' rants about why it's not automaticaly the best thing to move
> functionality into userspace.
> remember that the files covered by an AA policy can change as files are
> renamed. this isn't the case with SELinux so it doesn't have this sort
> of problem.
How about using the inotify interface on / to watch for file changes and
updating the SELinux policies on the fly. This could be done from a
userspace daemon and should require minimal SELinux changes.
The only possible problems I can see are the (hopefully) small gap
between the file change and updating the policy and the performance
problems of watching the whole system for changes.
Just my $0.02.
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