Subject: Re: security and journaling
From: Steve Lord <lord@sgi.com>
To: Ray Muno <muno@aem.umn.edu>
Cc: linux-xfs@oss.sgi.com
In-Reply-To: <20020930191821.GO15322@aem.umn.edu>
References: <1033412016.12588.12.camel@lws020.get2chip.com>
	<20020930185617.GA15397@tapu.f00f.org> <20020930151013.F24367@questra.com> 
	<20020930191821.GO15322@aem.umn.edu>
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Date: 30 Sep 2002 14:29:27 -0500
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On Mon, 2002-09-30 at 14:18, Ray Muno wrote:
> SHRED(1)                       FSF                       SHRED(1)
> 
> NAME
>        shred  -  delete  a file securely, first overwriting it to
>        hide its contents
> 
> SYNOPSIS
>        shred [OPTIONS] FILE [...]
> 
> ...stuff deleted
> 
>        CAUTION:  Note  that  shred  relies  on  a  very important
>        assumption: that the filesystem overwrites data in  place.
>        This  is the traditional way to do things, but many modern
>        filesystem designs do not satisfy  this  assumption.   The
>        following  are  examples  of filesystems on which shred is
>        not effective:
> 
>        * log-structured or journaled filesystems, such  as  those
>        supplied with
> 
>               AIX and Solaris (and JFS, ReiserFS, XFS, etc.)

If shred just overwrites in place it will be effective with XFS,
that man page is wrong.

Steve


-- 

Steve Lord                                      voice: +1-651-683-3511
Principal Engineer, Filesystem Software         email: lord@sgi.com