Re: [patch] to add device+inode check to ipt_owner.c - HACKED UP

[Luke Kenneth Casson Leighton <lkcl@lkcl.net>]

On Wed, Sep 08, 2004 at 12:14:50PM +0200, Arjan van de Ven wrote:
> On Wed, 2004-09-08 at 12:09, Luke Kenneth Casson Leighton wrote:
> > dear kernel people,
> > 
> > this is a first pass at attempting to add per-program firewall rule
> > checking to iptables.
> 
> question: any reason you didn't use something like selinux-like contexts
> instead of dentry/device pairs ? 

a very good question: stephen smalley described an approach in which
exactly what you suggest can be done.

please bear with me whilst i explain, then i will answer.

the issue is that FireFlier is an on-demand (user-driven) popup firewall
program [and there literally ISN'T any firewall program available for
linux that even remotely comes close to the same capabilities as
fireflier]

so rules are queued (ipt_queue) and the popup thrown at the user until
they select "yes, no, create-a-firewall-rule".

to parallel the same functionality i would need to place a hook in
selinux to catch an audit operation (hooks are already there), then
alert the user to it, then create a rule, recompile the policy, and
_then_ let the hook proceed.

i'm not sure if this would work!!!

so, i didn't want to use selinux contexts because  it involves
dynamically creating selinux policy rules.

fireflier is NOT a "create-it-once-then-apply-it-suck-it-and-see"
firewall program.

it's an on-demand "popup" firewall program where the default is
"block by virtue of the packet being in the ip_queue, awaiting
 user approval or disapproval".


unless... *shudder* ... you mean ... why didn't i consider getting
FireFlier to _create_ selinux contexts, blatting them into the policy
directly? (which i know is possible, there do exist binary policy
editing-and-writing tools).

well... if this approach turns out to be a total nightmare, then
your question is really appreciated because it makes me think of
other possibilities.

l.


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