Re: RFC/patch 1/6: wusb: add authorization control for devices

On Tuesday 24 April 2007, David Brownell wrote:
> On Tuesday 24 April 2007, Inaky Perez-Gonzalez wrote:
> > This patch introduces 'struct usb_device'->authorized. Devices with
> > that bit set can be used in the system (drivers are allow to
> > attach). Devices that don't will have the usb_probe routine aborting
> > driver binding.
> >
> > This is needed for WUSB devices: until we don't do the crypto
> > handshake, we can't allow the device to be used -- but in the
> > meantime, we need to be able to talk to it's default endpoint.
>
> How would this be different from testing whether
>
> 	udev->state == USB_STATE_UNAUTHENTICATED
>
> Other than "authenticated" != "authorized" ... as in, WUSB talks
> about the not-authenticated state, but a "not authorized" notion
> exceeds (what I recall of the) WUSB specs by presuming an identity
> based acceess control mechanism.  (Access control list, etc.)

Well, for once, the authorized-to-connect/authenticated are two
different concepts (as I have explained in previous emails).

On the case of udev->state, I considered that, but rejected it due
to the following reason: a non-authorized to connect device could
be in the DEFAULT/ADDRESS/CONFIGURED or SUSPENDED states, as what
differentiates from a normal device is that drivers are not bound
to it, so effectively, it cannot be used.

I am still pondering how much the USB_STATE_UNAUTHENTICATHED/
RECONNECTING states can be used for the WUSB auth model, as we need
the device up and running and ready to service requests on ep0 to
do the authentication--so that means the whole stack needs to recognize
it as a normal device.



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