Re: [Bug #11500] /proc/net bug related to selinux

Eric W. Biederman
2008-09-18T18:09:31Z

Stephen Smalley <sds@tycho.nsa.gov> writes:

> On Thu, 2008-09-18 at 08:38 -0400, Stephen Smalley wrote:
>> I do however think that the mantra that we can't require users to update
>> policy for kernel changes is unsupportable in general. The precise set
>> of permission checks on a given operation is not set in stone and it is
>> not part of the kernel/userland interface/contract. Policy isn't
>> "userspace"; it governs what userspace can do, and it has to adapt to
>> kernel changes.
>
> I should note here that for changes to SELinux, we have gone out of our
> way to avoid such breakage to date through the introduction of
> compatibility switches, policy flags to enable any new checks, etc
> (albeit at a cost in complexity and ever creeping compatibility code).
> But changes to the rest of the kernel can just as easily alter the set
> of permission checks that get applied on a given operation, and I don't
> think we are always going to be able to guarantee that new kernel + old
> policy will Just Work.

I know of at least 2 more directories that I intend to turn into
symlinks into somewhere under /proc/self. How do we keep from
breaking selinux policies when I do that?

For comparison how do we handle sysfs?
How do we handle device nodes in tmpfs?
Ultimately do we want to implement xattrs and inotify on /proc?
Or is there another way that would simplify maintenance?

Eric