From 060e447a7749c981bdc506fe8148e0563279de81 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Herm=C3=A8s=20B=C3=A9lusca-Ma=C3=AFto?=
 <hermes.belusca-maito@reactos.org>
Date: Sat, 26 Dec 2015 17:08:13 +0000
Subject: [PATCH] [NTVDM]: Cast all the number-of-sectors computations to
 DWORD/ULONG to prevent potential overflows. Should fix a strange floppy
 read/write corruption I noticed.

svn path=/trunk/; revision=70424
---
 reactos/subsystems/mvdm/ntvdm/bios/bios32/dskbios32.c | 4 ++--
 reactos/subsystems/mvdm/ntvdm/hardware/disk.c         | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/reactos/subsystems/mvdm/ntvdm/bios/bios32/dskbios32.c b/reactos/subsystems/mvdm/ntvdm/bios/bios32/dskbios32.c
index 9bc83c08801..a4731787bb4 100644
--- a/reactos/subsystems/mvdm/ntvdm/bios/bios32/dskbios32.c
+++ b/reactos/subsystems/mvdm/ntvdm/bios/bios32/dskbios32.c
@@ -608,8 +608,8 @@ VOID WINAPI BiosDiskService(LPWORD Stack)
                 setAH(0x03);
 
                 /* Number of 512-byte sectors in CX:DX */
-                NumSectors = DiskImage->DiskInfo.Cylinders * DiskImage->DiskInfo.Heads
-                                                           * DiskImage->DiskInfo.Sectors;
+                NumSectors = (ULONG)((ULONG)DiskImage->DiskInfo.Cylinders * DiskImage->DiskInfo.Heads)
+                                                                          * DiskImage->DiskInfo.Sectors;
                 setCX(HIWORD(NumSectors));
                 setDX(LOWORD(NumSectors));
             }
diff --git a/reactos/subsystems/mvdm/ntvdm/hardware/disk.c b/reactos/subsystems/mvdm/ntvdm/hardware/disk.c
index 4bc4fad11ea..7f448a6f81b 100644
--- a/reactos/subsystems/mvdm/ntvdm/hardware/disk.c
+++ b/reactos/subsystems/mvdm/ntvdm/hardware/disk.c
@@ -342,7 +342,7 @@ SeekDisk(IN PDISK_IMAGE DiskImage,
 
     /* Set position */
     // Compute the offset
-    FilePointer = ((Cylinder * DiskImage->DiskInfo.Heads + Head)
+    FilePointer = (DWORD)((DWORD)((DWORD)Cylinder * DiskImage->DiskInfo.Heads + Head)
                     * DiskImage->DiskInfo.Sectors + (Sector - 1))
                     * DiskImage->DiskInfo.SectorSize;
     FilePointer = SetFilePointer(DiskImage->hDisk, FilePointer, NULL, FILE_BEGIN);
@@ -373,7 +373,7 @@ ReadDisk(IN PDISK_IMAGE DiskImage,
     if (Result != 0x00)
         return Result;
 
-    BytesToRead = NumSectors * DiskImage->DiskInfo.SectorSize;
+    BytesToRead = (DWORD)NumSectors * DiskImage->DiskInfo.SectorSize;
 
     // FIXME: Consider just looping around filling each time the buffer...
 
@@ -434,7 +434,7 @@ WriteDisk(IN PDISK_IMAGE DiskImage,
     if (Result != 0x00)
         return Result;
 
-    BytesToWrite = NumSectors * DiskImage->DiskInfo.SectorSize;
+    BytesToWrite = (DWORD)NumSectors * DiskImage->DiskInfo.SectorSize;
 
     // FIXME: Consider just looping around filling each time the buffer...