Re: SMACK netfilter smacklabel socket match

From: Tilman Baumann
Date: Thu Dec 11 2008 - 05:25:39 EST



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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/