From 467e368cc1c6b50ed8ed3c517606ad59c4211f6c Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Wed, 22 Oct 2014 21:08:34 +0100
Subject: [PATCH] check for overflowing msg len when unpacking A

unclebadtouches catched this.

closes #141
---
 msg.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/msg.go b/msg.go
index 2b12cd48..6ed21a07 100644
--- a/msg.go
+++ b/msg.go
@@ -1005,7 +1005,7 @@ func unpackStructValue(val reflect.Value, msg []byte, off int) (off1 int, err er
 				if off == lenmsg {
 					break // dyn. update
 				}
-				if off+net.IPv4len > rdend {
+				if off+net.IPv4len > rdend || off+net.IPv4len > lenmsg {
 					return lenmsg, &Error{err: "overflow unpacking a"}
 				}
 				fv.Set(reflect.ValueOf(net.IPv4(msg[off], msg[off+1], msg[off+2], msg[off+3])))