On Mon, Nov 18, 2019 at 05:12:34PM +0100, Andrey Konovalov wrote: > On Sat, Nov 16, 2019 at 9:49 AM Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Fri, Nov 15, 2019 at 05:10:26PM +0100, Andrey Konovalov wrote: > > > On Fri, Nov 15, 2019 at 4:44 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > On Fri, 15 Nov 2019, 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]. > > > > > > > > There are so many different flags for those id structures, parsing and > > > > understanding them must be quite difficult. > > > > > > > > > I'm thinking of making a proper patch that will add a debugfs entry > > > > > like usb/drivers (and usb/hid_drivers?), that can be read to get > > > > > USB/HID device ids for all loaded drivers. Would that be acceptable? > > > > > Or should I use some other interface to do that? > > > > > > > > I can't think of a better way to get the information from a running > > > > kernel. > > > > > > > > There is another possibility, though. If the drivers are built as > > > > modules, the information is already available to userspace tools via > > > > depmod. You could get it from the modules.dep.bin file. This has the > > > > advantage that it will work even for drivers that aren't currently > > > > loaded. > > > > > > This is the same thing Greg mentions above, right? > > > > Yes. > > > > > Would this work for drivers that are built into the kernel (as =y)? > > > > No, sorry. There has not been any need to export that information to > > userspace as nothing has ever needed that. > > > > The only reason we exported that at all was to allow modules to > > auto-load to handle the device. > > OK, I see. Ideally we would want to support both builtin drivers and > modules. I'll then implement the approach with exporting the ids > through debugfs. I'll send a patch once I have it. Note, this is part of the build/link process (see what MODULE_DEVICE_TABLE() does), so I don't know if you will be able to do it in debugfs very easily. Why not put it in /sys/module/MODULE_NAME/ ? thanks, greg k-h
