On Tue, 2016-04-05 at 09:44 -0400, Greg KH wrote: > 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@xxxxxxxxxx> > > > > > > > > > > > > > > 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? One typically can't defeat the knowledgeable and determined person, but this doesn't mean you don't try. In the windows world, most DLP capabilities make use of Manufacturer/Model/Serial in combination with user and system to determine/record access. In the case of Linux audit, we would be closing the gate after the horse has bolted, but at least we know it has occurred. > > > - 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? Which means audit could be defeated anyway since one controls the OS, but again one still needs to try. > > > - 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 :) I was hoping for a configurable table that could be pre-seeded and either managed via the audit interface (add/delete/masked). Pre-seed with well known devices such as cd/dvd, usb mass storage, scsi devices with the RMB bit set, etc and go from there. We need to start somewhere ... > > thanks, > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
