media: usbvision: Fix invalid accesses after device disconnect

The syzbot fuzzer found two invalid-access bugs in the usbvision
driver.  These bugs occur when userspace keeps the device file open
after the device has been disconnected and usbvision_disconnect() has
set usbvision->dev to NULL:

	When the device file is closed, usbvision_radio_close() tries
	to issue a usb_set_interface() call, passing the NULL pointer
	as its first argument.

	If userspace performs a querycap ioctl call, vidioc_querycap()
	calls usb_make_path() with the same NULL pointer.

This patch fixes the problems by making the appropriate tests
beforehand.  Note that vidioc_querycap() is protected by
usbvision->v4l2_lock, acquired in a higher layer of the V4L2
subsystem.

Reported-and-tested-by: [email protected]

Signed-off-by: Alan Stern <[email protected]>
CC: <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

0 files changed, 0 insertions, 0 deletions