Subject: Re: [PATCH 7/7] secid reconciliation-v03: Enforcement for SELinux

From: Paul Moore <[email-masked]>
Date: Fri, 29 Sep 2006 13:50:28 -0400

James Morris wrote:
> On Fri, 29 Sep 2006, James Morris wrote:
> 
> 
>>On Fri, 29 Sep 2006, Paul Moore wrote:
>>
>>
>>>>It seems more of a pain to actually
>>>>prevent their use at the same time and/or explain strange/unnatural
>>>>behavior.
>>>
>>>Agreed, the solution that we agreed upon is much easier to implement and
>>>explain than a lot of the alternatives.
>>
>>Ok, can you please explain it further?
>>
>>i.e. show me what the policy looks like, exactly what the user is trying 
>>to achieve, and explain what happens to each packet exactly in terms of 
>>labeling on the input and output paths.
>  
> Also, why can't this be done just with xfrm labeling?

I believe the issue Venkat and I were discussing was how to handle the
case of multiple external labeling protocols, i.e. what to do if we get
a packet through labeled SA which has a CIPSO option.  As I've said
before, I don't believe this is something we will see much in practice
but I think we need to decide what to do: handle it somehow or just punt
on the problem and drop it.  Several people with experience with
external labeling have commented on how supporting both external
labeling protocols would be a good idea so Venkat and I are trying to
come up with a solution that works.

Please see my reponse with the pseudo code/policy examples as this might
help clear things up.

-- 
paul moore
linux security @ hp