[PATCH 6/6 RFC] netfilter: add audit netns ID

[Richard Guy Briggs]

On 2017-05-24 19:31, Pablo Neira Ayuso wrote:
> Cc'ing Eric Biederman.
> 
> On Thu, May 18, 2017 at 01:21:52PM -0400, Richard Guy Briggs wrote:
> > diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
> > index 59b63a8..0f77b2a 100644
> > --- a/net/bridge/netfilter/ebtables.c
> > +++ b/net/bridge/netfilter/ebtables.c
> > @@ -27,6 +27,7 @@
> >  #include <linux/smp.h>
> >  #include <linux/cpumask.h>
> >  #include <linux/audit.h>
> > +#define PROC_DYNAMIC_FIRST 0xF0000000U
> >  #include <net/sock.h>
> >  /* needed for logical [in,out]-dev filtering */
> >  #include "../br_private.h"
> > @@ -1075,7 +1076,8 @@ static int do_replace_finish(struct net *net, struct ebt_replace *repl,
> >  			ab = audit_log_start(current->audit_context, GFP_KERNEL,
> >  					     AUDIT_NETFILTER_CFG);
> >  			if (ab) {
> > -				audit_log_format(ab, "op=replace family=%u table=%s entries=%u",
> > +				audit_log_format(ab, "op=replace net=%u family=%u table=%s entries=%u",
> > +						 net->ns.inum - PROC_DYNAMIC_FIRST,
> 
> IIRC, there was a discussion on exposing netns i-node number to
> userspace time ago on netdev and Eric Biederman was not happy about
> this?

He was not happy about it being exposed in the /proc filesystem.  We've
been talking since then and while we've not come to a definitive
conclusion there is a communication channel open.

This is more of an RFC patch than the rest of this set and I didn't
seriously expect this one to be accepted, I did want to present the idea
to see if there were concerns or better ideas generated how to
differentiate this record from a seemingly identical one.  The only
other ID would be the network namespace' struct pointer.

At this stage, one thing that is missing is a device number to qualify
this namespace ID.

Once I started printing the namespace proc inode number (minus the
starting offset) in decimal, it was very clear what was happenning and
seemed worth sharing that debugging tool patch.

- RGB

--
Richard Guy Briggs <rgb at redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635