Re: SMACK netfilter smacklabel socket match

From: Tilman Baumann <tilman.baumann@collax.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Linux-Kernel <linux-kernel@vger.kernel.org>,
	linux-security-module@vger.kernel.org
Subject: Re: SMACK netfilter smacklabel socket match
Date: Thu, 30 Oct 2008 17:06:18 +0100	[thread overview]
Message-ID: <4909DB7A.7040209@collax.com> (raw)
In-Reply-To: <48FE9FCB.6070202@schaufler-ca.com>

Casey Schaufler wrote:
> Tilman Baumann wrote:
>>> If you're up to trying out something that you know is going to get
>>> rewhacked before it goes in anywhere let me know.
>>
>> Sure. I will be happy to use that.
>> Just tell me where to find it and how to use it and what I should look 
>> out for.
>>
> 
> You'll need to start out with Paul Moore's testing tree:
> 
> % git clone git://git.infradead.org/users/pcmoore/lblnet-2.6_testing
> 
> Apply the attached patch (attachments are discouraged for review purposes,
> but this is handier for this purpose) and compile.
> 
> This is NOT production code. Again, we're hashing out the netlabel api and
> we know that they are going to change. This is demo only. The amount of
> testing it's gotten is really small.
> 
> I have created a new system label "@", pronounced "at" and referred to as
> the internet label. Processes cannot be assigned the internet label. A
> subject with the internet label (as identified by a packet thus labeled)
> can write to any object and any subject can write to an object thus 
> labeled,
> thereby explicitly blowing a hole in the Access Control Policy.
> 
> Have fun, let me know what you hit next.

Sorry for the long delay. I was annoyingly occupied with other things.

I just tried this out. But one thing makes me wonder if I had understood 
what it should do.
The syntax for /smack/slhost is IP[/MASK] LABEL.
When I give one host (in my case generously 0.0.0.0/0 *g*) a label what 
is the significance of the @ label?
First I used the _ label here which had the effect that everything seems 
  to work but labeled processes still produced labeled packet which got 
slaughtered in different ways and degrees over the internet.
If I gave my slhost the @ label my machine was offline and did not even 
get pings out locally.

I get the feeling I did not understand the concept yet.
Sorry but if you don't mind giving me a hint...

-- 
Tilman Baumann
Software Developer
Collax GmbH . Boetzinger Strasse 60 . 79111 Freiburg . Germany

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