Hi, I'm working on a way to extend syzkaller [1] to support fuzzing of the USB subsystem. The idea is to be able to emulate various USB devices and fuzz communication between the emulated device and the kernel. I'm looking for a way to emulate devices from userspace. Similar to how tuntap allows to create virtual network interfaces and emit ethernet traffic by writing to /dev/net/tun. While googling for some information on this I found mentions of gadgetfs and functionfs. As far as I understand, they allow to turn a USB host into a gadget and provide a way to communicate with another host from a userspace application running on the gadget machine. There's also usbfs, which allows to communicate with a usb gadget directly from a userspace application. Am I right, that none of the above actually fit my needs? Is there some way to emulate USB devices from a userspace application via some kernel interface? If not, what would be the easiest way to implement one? I'm thinking this should be possible by adding some hooks into the kernel, the question is what to hook and where? Thanks! [1] https://github.com/google/syzkaller -- 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
