usb: core: add sanity checks when using bInterfaceClass with new_id

Check if that field is actually used and if so, bail out if it exeeds a
u8. Make it also future-proof by not requiring "exactly three"
parameters in new_id, but simply "more than two".

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 8d989b1..574f5a0 100644 (file)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -60,7 +60,10 @@ ssize_t usb_store_new_id(struct usb_dynids *dynids,
        dynid->id.idVendor = idVendor;
        dynid->id.idProduct = idProduct;
        dynid->id.match_flags = USB_DEVICE_ID_MATCH_DEVICE;
-       if (fields == 3) {
+       if (fields > 2 && bInterfaceClass) {
+               if (bInterfaceClass > 255)
+                       return -EINVAL;
+
                dynid->id.bInterfaceClass = (u8)bInterfaceClass;
                dynid->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
        }