staging: wlan-ng: properly check endpoint types

As syzkaller detected, wlan-ng driver does not do sanity check of
endpoints in prism2sta_probe_usb(), add check for xfer direction and type

Reported-and-tested-by: syzbot+c2a1fa67c02faa0de723@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=c2a1fa67c02faa0de723
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200722161052.999754-1-rkovhaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: rustylife

drivers/staging/wlan-ng/prism2usb.c

@@ -61,11 +61,25 @@ static int prism2sta_probe_usb(struct usb_interface *interface,
 			       const struct usb_device_id *id)
 {
 	struct usb_device *dev;
-
+	const struct usb_endpoint_descriptor *epd;
+	const struct usb_host_interface *iface_desc = interface->cur_altsetting;
 	struct wlandevice *wlandev = NULL;
 	struct hfa384x *hw = NULL;
 	int result = 0;
 
+	if (iface_desc->desc.bNumEndpoints != 2) {
+		result = -ENODEV;
+		goto failed;
+	}
+
+	result = -EINVAL;
+	epd = &iface_desc->endpoint[1].desc;
+	if (!usb_endpoint_is_bulk_in(epd))
+		goto failed;
+	epd = &iface_desc->endpoint[2].desc;
+	if (!usb_endpoint_is_bulk_out(epd))
+		goto failed;
+
 	dev = interface_to_usbdev(interface);
 	wlandev = create_wlan();
 	if (!wlandev) {