Subject: Re: securely erasing a hard disk
To: None <tls@rek.tjls.com>
From: Philip Jensen <philiprjensen@gmail.com>
List: tech-security
Date: 10/21/2005 15:03:46
On 10/21/05, Thor Lancelot Simon <tls@rek.tjls.com> wrote:
> On Fri, Oct 21, 2005 at 01:35:24PM +1300, Philip Jensen wrote:
> >
> > If so, then does the -P switch for the NetBSD rm command really
> > provide the "security" of data erasure people think they are getting?
> > Or should the man page have an addition of "If you are serious about
> > removing all traces of this file then ......."?
>
> Did you read the entire manual page? The -P option is the subject of
> extensive text in the BUGS section
BUGS
The -P option assumes that the underlying file system is a fixed-block
file system. UFS is a fixed-block file system, LFS is not. In additi=
on,
only regular files are overwritten, other types of files are not.
But it doesn't talk about the validity of the process for removing a
file. More specifically whether you should do something else if you
want to be more sure of erasing the file's contents.
> and a rather lengthy warning in the
> COMPATIBILITY section.
COMPATIBILITY
The rm utility differs from historical implementations in that the -f =
op-
tion only masks attempts to remove non-existent files instead of maski=
ng
a large variety of errors.
Also, historical BSD implementations prompted on the standard output, =
not
the standard error output.
-P is not mentioned in compatibility at all.
> I don't think we could really be much more
> specific about it than we already are.
>
> Thor
>