Re: Exporting USB device ids from the kernel

[Andrey Konovalov <andreyknvl@google.com>]

On Fri, Nov 15, 2019 at 4:06 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Fri, Nov 15, 2019 at 03:25:38PM +0100, Andrey Konovalov wrote:
> > Hi Greg and Alan,
> >
> > For USB fuzzing it would be nice to be able to export usb_device_id
> > structs from the kernel to facilitate the fuzzer with generating USB
> > descriptors that match to actual drivers. The same is required for
> > hid_device_id structs, since those are matched separately by the
> > usbhid driver (are there other cases like this?).
> >
> > Currently I have a hacky patch [1] that walks all drivers for USB and
> > HID buses and then prints all device ids for those drivers into the
> > kernel log. Those are manually parsed and built into the fuzzer [2]
> > and then used to generate USB descriptors [3].
>
> The kernel will spit out all device ids of all USB devices when found if
> you have CONFIG_USB_ANNOUNCE_NEW_DEVICES enabled, if you want to parse
> the log.
>
> Otherwise, just walk usbfs or sysfs and get the ids there.  If you use
> libusb you can do this with just a few lines of code, or worst case,
> just implement the same thing on your own (like lsusb used to do).
> Heck, just copy what lsusb does, or again worst case, parse the output
> of it.
>
> There's also 'lsusb.py' as part of usbutils that shows how to do this
> from within python in userspace, and if you really want it, we also
> export the whole raw usb descriptor is in sysfs as well, if you want to
> not trust how the kernel parses it.
>
> hope this helps,

Either I misunderstand you or you misunderstood me. I don't want to
see IDs of devices that are connected. I want to see all of the IDs
for all of the devices that might be connected and bound to some
driver at some point in the future. Essentially I want to all IDs that
are passed to MODULE_DEVICE_TABLE(usb, ...) and
MODULE_DEVICE_TABLE(hid, ...). Is it possible to obtain those via
usbfs/sysfs?