uwb: i1480-dfu: fix NULL-deref at probe

commit 4ce36271 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer should a malicious device lack endpoints.

Note that the dereference happens in the cmd and wait_init_done
callbacks which are called during probe.

Fixes: 1ba47da5 ("uwb: add the i1480 DFU driver")
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Cc: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/uwb/i1480/dfu/usb.c

@@ -362,6 +362,9 @@ int i1480_usb_probe(struct usb_interface *iface, const struct usb_device_id *id)
 				 result);
 	}
 
+	if (iface->cur_altsetting->desc.bNumEndpoints < 1)
+		return -ENODEV;
+
 	result = -ENOMEM;
 	i1480_usb = kzalloc(sizeof(*i1480_usb), GFP_KERNEL);
 	if (i1480_usb == NULL) {