[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Bug-tar] Security Question - Unused File Space from a file'sEOF to

From: Joerg Schilling
Subject: Re: [Bug-tar] Security Question - Unused File Space from a file'sEOF to end of physical block on disk
Date: Fri, 03 Feb 2006 14:35:52 +0100
User-agent: nail 11.2 8/15/04

"Stone, Todd -Systems" <address@hidden> wrote:

> Our system contains both UNCLASSIFIED and CLASSIFIED data.  Our security 
> agency (AF-CERT in our case) have procedures for copying from a mixed 
> classification system to UNCLASSIFIED media.
> Files occupy full blocks and the concern is over contents of the unused 
> (slack) space between the files's EOF (End-of-File) marker and physical end 
> of the data block as occupied on disk.  This unused data could be considered 
> CLASSIFIED if contents aren't zeroed out.  Does or has anyone modified 
> GNU-TAR to clear unallocated (slack) space?

You cannot reliably and (you should not) do this inside a tar implementation.

If the OS you are using does not do this by default, you should chose another
OS or filesystem implemenataion. I cannot speak for other OS, but Solaris 
grants you to clear the space at leat on UFS and I would guess this is also 
true for ZFS.


 EMail:address@hidden (home) Jörg Schilling D-13353 Berlin
       address@hidden                (uni)  
       address@hidden     (work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily

reply via email to

[Prev in Thread] Current Thread [Next in Thread]