[ros-diffs] [tkreuzer] 69760: [WIN32K] Check the size of RLE bitmaps, while decompressing. Fixes possible buffer overrun. Patch by Kamil Hornicek CORE-8735 #resolve

Author: tkreuzer
Date: Sat Oct 31 20:37:20 2015
New Revision: 69760

URL: http://svn.reactos.org/svn/reactos?rev=69760&view=rev
Log:
[WIN32K]
Check the size of RLE bitmaps, while decompressing. Fixes possible buffer overrun.
Patch by Kamil Hornicek
CORE-8735 #resolve

Modified:
    trunk/reactos/win32ss/gdi/eng/eng.h
    trunk/reactos/win32ss/gdi/eng/rlecomp.c
    trunk/reactos/win32ss/gdi/ntgdi/bitmaps.c

Modified: trunk/reactos/win32ss/gdi/eng/eng.h
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/gdi/eng/eng.h?rev=6...
==============================================================================
--- trunk/reactos/win32ss/gdi/eng/eng.h	[iso-8859-1] (original)
+++ trunk/reactos/win32ss/gdi/eng/eng.h	[iso-8859-1] Sat Oct 31 20:37:20 2015
@@ -52,4 +52,5 @@
     BYTE *CompressedBits,
     BYTE *UncompressedBits,
     LONG Delta,
-    ULONG iFormat);
+    ULONG iFormat,
+    ULONG cjSizeImage);

Modified: trunk/reactos/win32ss/gdi/eng/rlecomp.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/gdi/eng/rlecomp.c?r...
==============================================================================
--- trunk/reactos/win32ss/gdi/eng/rlecomp.c	[iso-8859-1] (original)
+++ trunk/reactos/win32ss/gdi/eng/rlecomp.c	[iso-8859-1] Sat Oct 31 20:37:20 2015
@@ -18,14 +18,14 @@
     RLE_DELTA = 2  /* Delta */
 };

-VOID DecompressBitmap(SIZEL Size, BYTE *CompressedBits, BYTE *UncompressedBits, LONG Delta, ULONG Format)
+VOID DecompressBitmap(SIZEL Size, BYTE *CompressedBits, BYTE *UncompressedBits, LONG Delta, ULONG Format, ULONG cjSizeImage)
 {
     INT x = 0;
     INT y = Size.cy - 1;
     INT c;
     INT length;
     INT width;
-    INT height = Size.cy - 1;
+    INT height = y;
     BYTE *begin = CompressedBits;
     BYTE *bits = CompressedBits;
     BYTE *temp;
@@ -40,7 +40,7 @@

_SEH2_TRY
     {
-        while (y >= 0)
+        while (y >= 0 && (bits - begin) <= cjSizeImage)
         {
             length = (*bits++) >> shift;
             if (length)

Modified: trunk/reactos/win32ss/gdi/ntgdi/bitmaps.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/gdi/ntgdi/bitmaps.c...
==============================================================================
--- trunk/reactos/win32ss/gdi/ntgdi/bitmaps.c	[iso-8859-1] (original)
+++ trunk/reactos/win32ss/gdi/ntgdi/bitmaps.c	[iso-8859-1] Sat Oct 31 20:37:20 2015
@@ -107,7 +107,6 @@
         pvCompressedBits = pvBits;
         pvBits = NULL;
         iFormat = (iFormat == BMF_4RLE) ? BMF_4BPP : BMF_8BPP;
-        cjSizeImage = 0;
     }

/* Allocate a surface */
@@ -117,7 +116,7 @@
                                  iFormat,
                                  fjBitmap,
                                  cjWidthBytes,
-                                 cjSizeImage,
+                                 pvCompressedBits ? 0 : cjSizeImage,
                                  pvBits);
     if (!psurf)
     {
@@ -136,7 +135,7 @@
         lDelta = WIDTH_BYTES_ALIGN32(nWidth, gajBitsPerFormat[iFormat]);

pvBits = psurf->SurfObj.pvBits;
-        DecompressBitmap(sizl, pvCompressedBits, pvBits, lDelta, iFormat);
+        DecompressBitmap(sizl, pvCompressedBits, pvBits, lDelta, iFormat, cjSizeImage);
     }

/* Get the handle for the bitmap */