On Thu, Aug 05, 2021 at 10:58:46AM -0700, Andi Kleen wrote:

On 8/5/2021 10:51 AM, Greg Kroah-Hartman wrote:

quoted

It's controlled by whatever you want to use in userspace.  usbguard has
been handling this logic in userspace for over a decade now just fine.

So how does that work with builtin USB drivers? Do you delay the USB binding
until usbguard starts up?

Yes.

quoted

quoted

This doesn't help us handle builtin drivers that initialize before user
space is up.

Then have the default setting for your bus be "unauthorized" like we
allow for some busses today.

We need some early boot drivers, just not all of them. For example in your
scheme we would need to reject all early platform drivers, which would break
booting. Or allow all early platform drivers, but then we exactly get into
the problem that there are far too many of them to properly harden.

Define "harden" please.  Why not just allow all platform drivers, they
should all be trusted.  If not, well, you have bigger problems...

Anyway, feel free to build on top of the existing scheme please, but do
not ignore it and try to create yet-another-way-to-do-this that I have
to maintain for the next 20+ years.

thanks,

greg k-h