From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422741AbWHEHzt (ORCPT ); Sat, 5 Aug 2006 03:55:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422755AbWHEHzt (ORCPT ); Sat, 5 Aug 2006 03:55:49 -0400 Received: from ug-out-1314.google.com ([66.249.92.169]:36977 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S1422741AbWHEHzt (ORCPT ); Sat, 5 Aug 2006 03:55:49 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=s/RXp4mLRlhfYd6cUUJ7ZhA+DMiM3RZNMixhgdjJpFkImRlGDa3qJWcoJTr9gSohbnF3N+bttpL0BIQX5qDh2uh6+PSJgWuDkWk4PI/F2PrX3HcUSnYWV74ONJj3z8jVpb9mD+laVNRbr1YEh1QtQSSyo4XsmG8U3fBEss3/OXY= Message-ID: Date: Sat, 5 Aug 2006 00:55:47 -0700 From: "Avinash Ramanath" To: arjan@infradead.org Subject: Re: Zeroing data blocks Cc: kernelnewbies@nl.linux.org, linux-kernel@vger.kernel.org In-Reply-To: <1152435182.3255.39.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1152435182.3255.39.camel@laptopd505.fenrus.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, As per your suggestion, if I write a file with zero bits, it would remap to other pages, and I might not zero the real pages. So is there any other way that I can access the pages that a file is using? On 7/9/06, Arjan van de Ven wrote: > On Sat, 2006-07-08 at 18:56 -0700, Avinash Ramanath wrote: > > I am trying to zero data blocks whenever an unlink is invoked as part > > of a secure delete filesystem. > [ > Hi, > > just a question... how secure do you want to be? > (just asking because zeros might not be the best pattern when protecting > against government type use :) I would be using zeroes multiple times followed by random bit patterns. > > I tried to zero the file by writing a buffer (of file size) with > > zeroes onto the file. > > that's not so nice since there is no guarantee that the filesystem or > the disk won't remap the data blocks underneath you... > > >