usbvision: revert commit 588afcc1

usbvision: revert commit 588afcc1

commit d5468d7afaa9c9e961e150f0455a14a9f4872a98 upstream.

Commit 588afcc1c0e4 ("[media] usbvision fix overflow of interfaces
array")' should be reverted, because:

* "!dev->actconfig->interface[ifnum]" won't catch a case where the value
is not NULL but some garbage. This way the system may crash later with
GPF.

* "(ifnum >= USB_MAXINTERFACES)" does not cover all the error
conditions. "ifnum" should be compared to "dev->actconfig->
desc.bNumInterfaces", i.e. compared to the number of "struct
usb_interface" kzalloc()-ed, not to USB_MAXINTERFACES.

* There is a "struct usb_device" leak in this error path, as there is
usb_get_dev(), but no usb_put_dev() on this path.

* There is a bug of the same type several lines below with number of
endpoints. The code is accessing hard-coded second endpoint
("interface->endpoint[1].desc") which may not exist. It would be great
to handle this in the same patch too.

* All the concerns above are resolved by already-accepted commit fa52bd50
("[media] usbvision: fix crash on detecting device with invalid
configuration")

* Mailing list message:
http://www.spinics.net/lists/linux-media/msg94832.html

Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Luis Henriques <luis.henriques@canonical.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>