Changeset 72577 in vbox for trunk/src/VBox/Storage

Timestamp:

Jun 15, 2018 9:31:58 PM (6 years ago)

Author:

vboxsync

Message:

Storage/VHD: Stay within possible limits of the VDH spec for the block allocation table and reject images violating the spec, missing status code check [build fix]

File:

• trunk/src/VBox/Storage/VHD.cpp (modified) (2 diffs)

trunk/src/VBox/Storage/VHD.cpp

@@ -47 +47 @@
 #define VHD_MAX_SIZE    (2 * _1T)
 /** Maximum number of 512 byte sectors for a VHD image. */
-#define VHD_MAX_SECTORS ((uint32_t)(VHD_MAX_SIZE / VHD_SECTOR_SIZE))
+#define VHD_MAX_SECTORS (VHD_MAX_SIZE / VHD_SECTOR_SIZE)
 
 /* This is common to all VHD disk types and is located at the end of the image */
@@ -756 +756 @@
     AssertMsg(!(pImage->cbDataBlock % VHD_SECTOR_SIZE), ("%s: Data block size is not a multiple of %!\n", __FUNCTION__, VHD_SECTOR_SIZE));
 
-    /* Bail out if the number of BAT entries exceeds the number of sectors for a maximum image. */
-    if (pImage->cBlockAllocationTableEntries > VHD_MAX_SECTORS)
+    /*
+     * Bail out if the number of BAT entries exceeds the number of sectors for a maximum image.
+     * Lower the number of sectors in the BAT as a few sectors are already occupied by the footers
+     * and headers.
+     */
+    if (pImage->cBlockAllocationTableEntries > (VHD_MAX_SECTORS - 2))
         return VERR_VD_VHD_INVALID_HEADER;