On Tue, Apr 05, 2016 at 11:07:48PM +1000, Burn Alting wrote:
On Mon, 2016-04-04 at 14:53 -0700, Greg KH wrote:
> On Mon, Apr 04, 2016 at 02:48:43PM -0700, Greg KH wrote:
> > On Mon, Apr 04, 2016 at 05:33:10PM -0400, Steve Grubb wrote:
> > > On Monday, April 04, 2016 05:56:26 AM Greg KH wrote:
> > > > On Mon, Apr 04, 2016 at 12:02:42AM -0400, wmealing wrote:
> > > > > From: Wade Mealing <wmealing(a)redhat.com>
> > > > >
> > > > > Gday,
> > > > >
> > > > > I'm looking to create an audit trail for when devices are
added or removed
> > > > > from the system.
> > > >
> > > > Then please do it in userspace, as I suggested before, that way you
> > > > catch all types of devices, not just USB ones.
> > > >
> > > > Also I don't think you realize that USB interfaces are what are
bound to
> > > > drivers, not USB devices, so that is going to mess with any
attempted
> > > > audit trails here. How are you going to distinguish between the 5
> > > > different devices that just got plugged in that all have 0000/0000
as
> > > > vid/pid for them because they are "cheap" devices from
China, yet do
> > > > totally different things because they are different _types_ of
devices?
> > >
> > > This sounds like vid/pid should be captured in the event.
> >
> > The code did that, the point is, vid/pid means nothing in the real
> > world. So why are you going to audit anything based on it? :)
>
> Oh wait, it's worse, it is logging strings, which are even more
> unreliable than vid/pid values. It's pretty obvious this has not been
> tested on any large batch of real-world devices, or thought through as
> to why any of this is even needed at all.
>
> So why is this being added? Who needs/wants this? What are their
> requirements here?
As a consumer of auditd events for security purposes, the questions I
would like answered via the sort of audit framework Wade is putting
together are
- when was a (possible) removable media device plugged into a system and
what were the device details - perhaps my corporation has a policy on
what devices are 'official' and hence one looks for alternatives,
and/or,
How do you determine if a USB device is "official" or not? What
attribute(s) are you going to care about that can't be trivially
spoofed?
- was it there at boot ? (in case someone adds and removes such
devices
when powered off), and eventually
What if you booted off of it?
- has an open for write (or other system calls) occurred on
designated
removable media? (i.e. what may have been written to removable media -
cooked or raw) - Yes, this infers a baseline of what's connected or an
efficient means of working out if a device is 'removable' at system call
time.
Yes, determining "removable" is non-trivial, good luck with that :)
thanks,
greg k-h