[nrf fromtree] usb: device_next: fix null pointer dereference in Get Interface

Respond with a Request Error in default and addressed states.

Signed-off-by: Johann Fischer <[email protected]>
(cherry picked from commit 1a5ab2c)
Signed-off-by: Tomasz Moń <[email protected]>

Author: jfischer-no

subsys/usb/device_next/usbd_ch9.c

@@ -858,7 +858,13 @@ static int sreq_get_interface(struct usbd_context *const uds_ctx,
 		return 0;
 	}
 
+	/* Treat as error in default (not specified) and addressed states. */
 	cfg_nd = usbd_config_get_current(uds_ctx);
+	if (cfg_nd == NULL) {
+		errno = -EPERM;
+		return 0;
+	}
+
 	cfg_desc = cfg_nd->desc;
 
 	if (setup->wIndex > UINT8_MAX ||