From 8385f137b50242c632bd8f91a495a2b7e5adfee4 Mon Sep 17 00:00:00 2001
From: Alexandre Julliard <julliard@winehq.org>
Date: Fri, 1 Dec 2006 11:38:52 +0100
Subject: [PATCH] ntdll: Don't free the DOS area when a broken app passes a
 NULL pointer to NtFreeVirtualMemory.

---
 dlls/ntdll/virtual.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dlls/ntdll/virtual.c b/dlls/ntdll/virtual.c
index c62390ac512..573072e2391 100644
--- a/dlls/ntdll/virtual.c
+++ b/dlls/ntdll/virtual.c
@@ -1430,6 +1430,9 @@ NTSTATUS WINAPI NtFreeVirtualMemory( HANDLE process, PVOID *addr_ptr, SIZE_T *si
     size = ROUND_SIZE( addr, size );
     base = ROUND_ADDR( addr, page_mask );
 
+    /* avoid freeing the DOS area when a broken app passes a NULL pointer */
+    if (!base && !(type & MEM_SYSTEM)) return STATUS_INVALID_PARAMETER;
+
     RtlEnterCriticalSection(&csVirtual);
 
     if (!(view = VIRTUAL_FindView( base )) ||