[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
Re: [Bug-tar] Security Question - Unused File Space from a file'sEOF to end of physical block on disk
Fri, 03 Feb 2006 14:35:52 +0100
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 (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily