USB reset fails when using a LimeSDR Mini on FreeBSD

[Jan Behrens]

On Thu, 2 Jul 2020 10:54:27 +0200
Hans Petter Selasky <hps at selasky.org> wrote:

> On 2020-07-02 10:47, Jan Behrens wrote:
> > But wouldn't both drivers require access to the entries in /dev ?
> 
> Yes, user-space drivers would require access to /dev, yes, but kernel 
> drivers not, like mouse, keyboard, storage, network.
> 
> > Thus not every user could mess with any USB device, or do I get it
> > wrong?
> 
> A so-called composite USB device may appear like a USB storage device 
> (kernel driver) and a security token (firefox). Firefox can only grab 
> the device if you set the proper permissions for /dev of course, but the 
> reset device IOCTL then also becomes possible, which is why we currently 
> block it for non-root.
> 
> --HPS

Okay, so if I understand it right, the problem is due to devices that
shall be partly accessible by root, and partly by users. Some device
nodes (e.g. /dev/usb/2.2.1 ) while others (e.g. /dev/usr/2.2.2 ) are
limited to root access only. An USB reset always affects all devices
(e.g. also /dev/usb/2.2.2, 2.2.3, etc.), right?

Disregarding implementation complexity, I'd say that resetting a USB
device should only be possible if a user has access to all sub-devices
(or even better to a special device node that represents the device as
a whole).

That sounds better than adding a sysctl option to me. But I assume that
would require a lot of changes in the code?


Regards,
Jan