[pschweitzer] 50090: [FASTFAT] Fix for a buffer overflow and then a buffer overrun (if ever it fixes something) The way filenames are handled for FAT entries should be REALLY simplified. This would...

Author: pschweitzer
Date: Wed Dec 22 00:13:03 2010
New Revision: 50090

URL: http://svn.reactos.org/svn/reactos?rev=50090&view=rev
Log:
[FASTFAT]
Fix for a buffer overflow and then a buffer overrun (if ever it fixes something)
The way filenames are handled for FAT entries should be REALLY simplified. This would prevent such errors.
Thus, there are more magic values in fastfat driver than everywhere else in ReactOS which makes proper fixing hard (impossible?).
Finally, the code for that fix is crappy, but I don't care, it fits the rest of the fastfat driver code.
*pissed off*
Fixes CID #2502

Modified:
    trunk/reactos/drivers/filesystems/fastfat/volume.c

Modified: trunk/reactos/drivers/filesystems/fastfat/volume.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/filesystems/fastfat...
==============================================================================
--- trunk/reactos/drivers/filesystems/fastfat/volume.c [iso-8859-1] (original)
+++ trunk/reactos/drivers/filesystems/fastfat/volume.c [iso-8859-1] Wed Dec 22 00:13:03 2010
@@ -220,8 +220,16 @@
   }
   else
   {
-    RtlCopyMemory(VolumeLabelDirEntry.Fat.Filename, cString, LabelLen);
-    memset(&VolumeLabelDirEntry.Fat.Filename[LabelLen], ' ', 11 - LabelLen);
+    RtlCopyMemory(VolumeLabelDirEntry.Fat.Filename, cString, max(sizeof(VolumeLabelDirEntry.Fat.Filename), LabelLen));
+    if (LabelLen > sizeof(VolumeLabelDirEntry.Fat.Filename))
+    {
+      memset(VolumeLabelDirEntry.Fat.Ext, ' ', sizeof(VolumeLabelDirEntry.Fat.Ext));
+      RtlCopyMemory(VolumeLabelDirEntry.Fat.Ext, cString + sizeof(VolumeLabelDirEntry.Fat.Filename), LabelLen - sizeof(VolumeLabelDirEntry.Fat.Filename));
+    }
+    else
+    {
+      memset(&VolumeLabelDirEntry.Fat.Filename[LabelLen], ' ', sizeof(VolumeLabelDirEntry.Fat.Filename) - LabelLen);
+    }
     VolumeLabelDirEntry.Fat.Attrib = 0x08;
   }