Input: kbtab - sanity check for endpoint type

commit c88090dfc84254fa149174eb3e6a8458de1912c4 upstream.

The driver should check whether the endpoint it uses has the correct
type.

Reported-by: syzbot+c7df50363aaff50aa363@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/tablet/kbtab.c b/drivers/input/tablet/kbtab.c
index 4d9d649..b7ea64e 100644
--- a/drivers/input/tablet/kbtab.c
+++ b/drivers/input/tablet/kbtab.c
@@ -125,6 +125,10 @@
 	if (intf->cur_altsetting->desc.bNumEndpoints < 1)
 		return -ENODEV;
 
+	endpoint = &intf->cur_altsetting->endpoint[0].desc;
+	if (!usb_endpoint_is_int_in(endpoint))
+		return -ENODEV;
+
 	kbtab = kzalloc(sizeof(struct kbtab), GFP_KERNEL);
 	input_dev = input_allocate_device();
 	if (!kbtab || !input_dev)
@@ -163,8 +167,6 @@
 	input_set_abs_params(input_dev, ABS_Y, 0, 0x1750, 4, 0);
 	input_set_abs_params(input_dev, ABS_PRESSURE, 0, 0xff, 0, 0);
 
-	endpoint = &intf->cur_altsetting->endpoint[0].desc;
-
 	usb_fill_int_urb(kbtab->irq, dev,
 			 usb_rcvintpipe(dev, endpoint->bEndpointAddress),
 			 kbtab->data, 8,