config_mbr: Fix integer overflow

The values need to be converted to loff_t *before* performing
the multiplication, else any sector offset past MAX_INT
bytes will overflow.

Change-Id: Ib8992f28aa4119ac7b4ad354b2448c4b0cfaf846
Signed-off-by: Andrew Boie <[email protected]>

Author: Andrew Boie

libdiskconfig/config_mbr.c

@@ -152,7 +152,7 @@ mk_ext_pentry(struct disk_info *dinfo, struct part_info *pinfo, uint32_t *lba,
 
     /* we are going to write the ebr at the current LBA, and then bump the
      * lba counter since that is where the logical data partition will start */
-    item->offset = (*lba) * dinfo->sect_size;
+    item->offset = ((loff_t)(*lba)) * dinfo->sect_size;
     (*lba)++;
 
     ebr = (struct pc_boot_record *) &item->data;