linux-kernel - Re: SMACK netfilter smacklabel socket match

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Date:	Thu, 11 Dec 2008 11:18:43 +0100
From:	Tilman Baumann <tilman.baumann@...lax.com>
To:	Casey Schaufler <casey@...aufler-ca.com>
Cc:	Linux-Kernel <linux-kernel@...r.kernel.org>,
	linux-security-module@...r.kernel.org
Subject: Re: SMACK netfilter smacklabel socket match


Am 11.12.2008 um 01:03 schrieb Casey Schaufler:

>
>>
>> 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...
>>
>
> OK, Paul and I knocked our heads together until we got the behavior  
> and
> interfaces ironed out if not to our mutual satisfaction at least to a
> workable level. Paul's next tree:
>
>   % git clone git://git.infradead.org/users/pcmoore/lblnet-2.6_next

Nice, I'm eager to try that out.

>
>
> has the current version. There are a couple interesting things going  
> on.
>
>   - /smack/nltype is gone. It never lived up to its promise and is no
>     longer required to determine the labeling scheme.
>   - /smack/netlabel replaces the earlier /smack/slhost because it  
> better
>     describes what it gets used for.
>   - The "@" label (pronounced "web") has been added to the list of  
> special
>     labels. A packet with the web label will get delivered anywhere. A
>     network address specified to have the web label can be written  
> to by
>     any process. Processes can not have the web label.
>   - An incoming packet from an address in the netlabel list that has  
> a CIPSO
>     label attached will still use the label from the CIPSO packet.
>   - An unlabeled packet coming from an address in the netlabel list  
> will be
>     given the label associated with that address.
>   - A process that wants to send a packet to an address on the list  
> needs
>     write access to the label associated with that address. The  
> packet will
>     be sent unlabeled if it is allowed.
>
>

I guess the question will be, can the /smack/netlabel network also be  
0.0.0.0/0?
I know, that's not how it was meant to be used, but that's what would
solve my problems with outgoing labeled packets.

However, I will try this out...
Thanks

Regards
  Tilman
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