From 6a1e14fccd09c02d8991008897e825adaa89f4f5 Mon Sep 17 00:00:00 2001
From: Randy Mackay <rmackay9@yahoo.com>
Date: Wed, 20 Sep 2017 09:23:15 +0900
Subject: [PATCH] Sub: command-long DO_SET_HOME check first param is zero

---
 ArduSub/GCS_Mavlink.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ArduSub/GCS_Mavlink.cpp b/ArduSub/GCS_Mavlink.cpp
index bd945f258d..6dcda8749e 100644
--- a/ArduSub/GCS_Mavlink.cpp
+++ b/ArduSub/GCS_Mavlink.cpp
@@ -1090,6 +1090,10 @@ void GCS_MAVLINK_Sub::handleMessage(mavlink_message_t* msg)
                     result = MAV_RESULT_ACCEPTED;
                 }
             } else {
+                // ensure param1 is zero
+                if (!is_zero(packet.param1)) {
+                    break;
+                }
                 // sanity check location
                 if (!check_latlng(packet.param5, packet.param6)) {
                     break;