Don't trust cbSize

[Uwe Bonnes]

Changelog:
	dlls/ntdll/heap.c: RtlHeapWalk()
	Don't trust the cbSize input parameter

The MS CRT implementation of _heapwalk doesn't explizitly set cbSize. This
may result in a bogus value for cbSize 
-- 
Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
Index: wine/dlls/ntdll/heap.c
===================================================================
RCS file: /home/wine/wine/dlls/ntdll/heap.c,v
retrieving revision 1.33
diff -u -w -r1.33 heap.c
--- wine/dlls/ntdll/heap.c	25 Feb 2005 14:07:57 -0000	1.33
+++ wine/dlls/ntdll/heap.c	2 Mar 2005 16:49:02 -0000
@@ -1503,6 +1503,7 @@
     }
     else
     {
+        ARENA_INUSE *pArena;
         ptr = entry->lpData;
         sub = &heapPtr->subheap;
         while (sub)
@@ -1522,7 +1523,11 @@
             ret = STATUS_NO_MORE_ENTRIES;
             goto HW_end;
         }
-
+	/* Native MSVCRT _heapwalk() doesn't set cbData */
+	pArena = (ARENA_INUSE *)ptr -1;
+	if (pArena->magic == ARENA_INUSE_MAGIC)
+	  ptr += pArena->size & ARENA_SIZE_MASK; /* point to next arena */
+	else
         ptr += entry->cbData; /* point to next arena */
         if (ptr > (char *)currentheap + currentheap->size - 1)
         {   /* proceed with next subheap */