From 5c9b46a52cbb654debdaf77a827dc4b2e48abc35 Mon Sep 17 00:00:00 2001
From: Peter Veenstra <qbix79@users.sourceforge.net>
Date: Tue, 27 Jan 2004 14:26:43 +0000
Subject: [PATCH] don't allow dos it's memory to be freed

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@1605
---
 src/dos/dos_memory.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/dos/dos_memory.cpp b/src/dos/dos_memory.cpp
index 2279c216..e2e3d9d3 100644
--- a/src/dos/dos_memory.cpp
+++ b/src/dos/dos_memory.cpp
@@ -165,6 +165,11 @@ bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks) {
 
 bool DOS_FreeMemory(Bit16u segment) {
 //TODO Check if allowed to free this segment
+	if ((segment-1) < MEM_START){
+		LOG(LOG_DOSMISC,LOG_ERROR)("Program tried to free %X ---ERROR",segment);
+		return false;
+	}
+      
 	DOS_MCB mcb(segment-1);
 	mcb.SetPSPSeg(MCB_FREE);
 	DOS_CompressMemory();