USB: usbfs: Filter flags passed in from user space

USB: usbfs: Filter flags passed in from user space

commit 446f666da9f019ce2ffd03800995487e79a91462 upstream.

USBDEVFS_URB_ISO_ASAP must be accepted only for ISO endpoints.
Improve sanity checking.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>