F21 System Wide Change: Workstation: Disable firewall

Simo Sorce simo at redhat.com
Wed Apr 16 16:51:56 UTC 2014


On Wed, 2014-04-16 at 18:43 +0200, Tomasz Torcz wrote:
> On Wed, Apr 16, 2014 at 12:32:02PM -0400, Simo Sorce wrote:
> > > > I think what you are describing could be probably realized with SELinux
> > > > today, just with a special setroubleshoot frontend that catches the AVC
> > > > when the service tries to listen and ask the user if he wants to allow
> > > > it.
> > > >
> > > > However this would still not be completely sufficient as you completely
> > > > lack any context about what network you are operating on.
> > > >
> > > > The firewall's purpose is to block access to local services on bad
> > > > networks too, it is not a binary open/close equation when you have
> > > > machines (laptops) that roam across a variety of networks.
> > > >
> > > > Simo.
> > > >
> > > Nothing worse then asking Users Security related questions about opening
> > > firewall ports.
> > > Users will just answer yes, whether or not they are being hacked.
> > > 
> > > firefox wants to listen on port 9900 in order to see this page, OK?
> > 
> > 
> > Which is not what I proposed Dan.
> > 
> > I in fact said we should *NOT* ask per application.
> > 
> > What we should ask is one single question, upon connecting to an unknown
> > network: "Is this network trusted ?"
> > 
> > If yes you open up to the local network. If no you keep ports not
> > accessible on that network.
> 
>   But firewalld currently lacks flexibility to express this fully.
> Firewalld only classifies ”whole” interfaces, which breaks badly in
> many situations.  Consider following scenario:  VM with single 
> network interface.  This single interface has RFC1918 IPv4 address AND
> globally accesible IPv6 address.  How it should be described
> in firewalld?
> 
>   – for any IPv4 incoming connection, this interface is in ”trusted” (”home”?
>     I never know what home/work/dmz/etc really mean)
>   – for IPv6 incoming connection from 2001:6a0:138:1::/64 subnet, the zone
>     is still ”trusted”
>   – for any other incoming connection the zone is ”public” (I hope this
>     means ”general Internet”).
> 
>   Above is trivial in iptables, but impossible with firewalld's zones.

Clearly firewalld zones need to be improved.
The underlying iptables (and nftables in the future) clearly are
capable.

The fact firewalld is currently limited doesn't mean we need to write
off the approach. There is still value in being able to say virt0 is
trusted and wlan0 is not.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York



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