Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 13 Feb 2002 04:34:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 13 Feb 2002 04:34:35 -0500 Received: from hermine.idb.hist.no ([158.38.50.15]:23304 "HELO hermine.idb.hist.no") by vger.kernel.org with SMTP id ; Wed, 13 Feb 2002 04:34:21 -0500 Message-ID: <3C6A32ED.755159F3@aitel.hist.no> Date: Wed, 13 Feb 2002 10:33:33 +0100 From: Helge Hafting X-Mailer: Mozilla 4.76 [no] (X11; U; Linux 2.5.4-dj1 i686) X-Accept-Language: no, en, en MIME-Version: 1.0 To: Andreas Ferber , linux-kernel@vger.kernel.org Subject: Re: secure erasure of files? In-Reply-To:

<20020212165504.A5915@devcon.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andreas Ferber wrote: > I don't know if any filesystem currently relocates blocks if you > overwrite a file, but it's certainly possible and allowed (everything > else except the filesystem itself simply must not care where the data > actually ends up on the disk). > A log-structured fs will write new blocks everytime, afaik. Ext3 with data journalling keeps copies of recently written data in the journal. Now, if you create a "secret" file and then overwrite it you'll still find a copy in the journal until the journal wraps It may not wrap if the next thing you do is umount/shutdown. A secure rm must know the fs it works with. A better solution is to overwrite the entire partition with garbage. The only perfect way is to destroy the magnetic surfaces though. Helge Hafting - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/