From 8f7c0735143cdcc14df4cc3457c96f7508563318 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <hillbrand@ucdavis.edu>
Date: Wed, 19 Dec 2018 17:12:43 -0700
Subject: [PATCH] pcbnew: Check for valid pointer before deref

In legacy toolkit, we do not keep the corner pointers, so dereferencing
causes crashes.

Fixes: lp:1808852
* https://bugs.launchpad.net/kicad/+bug/1808852

(cherry picked from commit 4aeef1e09e0f55adcac7a88cee8b0479d19be7a8)
---
 pcbnew/class_zone.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pcbnew/class_zone.h b/pcbnew/class_zone.h
index 7a3fa96984..769ff58dde 100644
--- a/pcbnew/class_zone.h
+++ b/pcbnew/class_zone.h
@@ -206,8 +206,10 @@ public:
     int GetSelectedCorner() const
     {
         // Transform relative indices to global index
-        int globalIndex;
-        m_Poly->GetGlobalIndex( *m_CornerSelection, globalIndex );
+        int globalIndex = -1;
+
+        if( m_CornerSelection )
+            m_Poly->GetGlobalIndex( *m_CornerSelection, globalIndex );
 
         return globalIndex;
     }