HID: logitech-hidpp: add boundary check for name retrieval

The HID response has a limited size. Do not trust the value returned by
hardware, check that it really fits in the message.
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-logitech-hidpp.c

@@ -313,6 +313,9 @@ static char *hidpp_get_unifying_name(struct hidpp_device *hidpp_dev)
 
 	len = response.rap.params[1];
 
+	if (2 + len > sizeof(response.rap.params))
+		return NULL;
+
 	name = kzalloc(len + 1, GFP_KERNEL);
 	if (!name)
 		return NULL;