From 74357ced0c0ee2e78d6b68af8116c158111c7a27 Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Wed, 21 Feb 2018 15:17:02 +0200
Subject: [PATCH] Fixed read of potentially junk values in ZScript parser

The following ill-formed ZScript code might crash targets with sizeof(int) != sizeof(void*) like 64-bit Intel
class test { void func() { if (true) ( return; ) } }
---
 src/scripting/zscript/zcc_parser.cpp |  1 +
 src/scripting/zscript/zcc_parser.h   | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/scripting/zscript/zcc_parser.cpp b/src/scripting/zscript/zcc_parser.cpp
index cb927bb502..02d78021bd 100644
--- a/src/scripting/zscript/zcc_parser.cpp
+++ b/src/scripting/zscript/zcc_parser.cpp
@@ -267,6 +267,7 @@ static void ParseSingleFile(FScanner *pSC, const char *filename, int lump, void
 
 	while (sc.GetToken())
 	{
+		value.Largest = 0;
 		value.SourceLoc = sc.GetMessageLine();
 		switch (sc.TokenType)
 		{
diff --git a/src/scripting/zscript/zcc_parser.h b/src/scripting/zscript/zcc_parser.h
index 3c1e55805e..5f0889fd2e 100644
--- a/src/scripting/zscript/zcc_parser.h
+++ b/src/scripting/zscript/zcc_parser.h
@@ -7,11 +7,31 @@
 
 struct ZCCToken
 {
+	template <typename... Ts>
+	struct TLargest;
+
+	template <typename T>
+	struct TLargest<T>
+	{
+		using Type = T;
+	};
+
+	template <typename T, typename U, typename... Ts>
+	struct TLargest<T, U, Ts...>
+	{
+		using Type = typename TLargest<
+			typename std::conditional<
+				(sizeof(T) > sizeof(U)), T, U
+			>::type, Ts...
+		>::Type;
+	};
+
 	union
 	{
 		int Int;
 		double Float;
 		FString *String;
+		TLargest<decltype(Int), decltype(Float), decltype(String)>::Type Largest;
 	};
 	int SourceLoc;