Re: How to audit socket close system call?

[Steve Grubb <sgrubb@redhat.com>]

On Saturday, December 20, 2014 11:39:47 AM Hassan Sultan wrote:
> Are you interested in the syscalls on sockets specifically, or are you
> interested in the network connections underlying these calls instead ?
> 
> You could use netfilter/conntrack instead of auditd if your interest
> really is the network connections rather than sockets.

There is also an AUDIT target for netfilter rules so that events you are 
interested in are recorded in the audit log.

-Steve

> You'll get notified of the various TCP states, so even if a socket is closed
> rather than shutdown (say when a process dies), you should be able to know
> about it that way.
> 
> Thanks,
> 
> Hassan
> 
> On Fri, 19 Dec 2014 06:37:15 -0800, Steve Grubb <sgrubb@redhat.com> wrote:
> > On Friday, December 19, 2014 02:06:52 PM Jie Cui wrote:
> >> How to audit socket close system call?
> > 
> > There's not a good answer on that one.
> > 
> >> I can audit the socket connection by 'connect' system call.
> >> I can also audit the socket termination by 'shutdown' system call.
> >> But I can't figure out how to audit when the socket is closed.
> > 
> > In the past, the kernel developers said that is an exercise left to post
> > processing in user space. Meaning that we'd have to collect everything
> > and
> > then sort it out after the fact. You have the FD returned from
> > socket(2). So,
> > you can audit closes and then match the FD.
> > 
> > Unfortunately, you'll get all closes for all programs unless you had
> > some way
> > to restrict it to the process in question. There is a patch under
> > development
> > for audit by process name. That would at least have allowed restricting
> > closes
> > to a particular program which would be more manageable.
> > 
> >> Does the 'close' system call works?
> > 
> > Yes.
> > 
> >> However all the file close events will also be auditing. That's not
> >> what I
> >> want.
> > 
> > I can understand. But, there is nothing in the present kernel except pid,
> > auid, and subj_type to restrict the auditing in a logical way. If you can
> > think of another way, please propose it. But all the kernel has to work
> > with
> > is an fd number and what's in the process struct. Audit by process name
> > holds
> > the most hope for limiting what gets collected.
> > 
> > -Steve
> > 
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