From owner-freebsd-security Thu May 20 0:33: 9 1999 Delivered-To: freebsd-security@freebsd.org Received: from ints.ru (ints.ru [194.67.173.1]) by hub.freebsd.org (Postfix) with ESMTP id 24EEE14FFF for ; Thu, 20 May 1999 00:33:06 -0700 (PDT) (envelope-from ilmar@ws-ilmar.ints.ru) Received: from ws-ilmar.ints.ru (ws-ilmar.ints.ru [194.67.173.16]) by ints.ru (8.9.2/8.9.2) with ESMTP id LAA09659; Thu, 20 May 1999 11:33:05 +0400 (MSD) Received: from localhost (localhost [127.0.0.1]) by ws-ilmar.ints.ru (8.9.2/8.9.1) with ESMTP id LAA20546; Thu, 20 May 1999 11:33:04 +0400 (MSD) Date: Thu, 20 May 1999 11:33:04 +0400 (MSD) From: "Ilmar S. Habibulin" To: Warner Losh Cc: posix1e@cyrus.watson.org, freebsd-security@FreeBSD.ORG Subject: Re: secure deletion In-Reply-To: <199905200624.AAA04145@harmony.village.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Thu, 20 May 1999, Warner Losh wrote: > There is a certain segment of the community that would use it. If > there was zero overhead (beyond a bit compare on unlink) when not > used, binary compatible with current disks and a fairly clean > implementation, then I think that there would be support for its > inclusion. My implementation was very simple. In order to secure ;-) delete file user have to set special flag (bit) of inode. I think, that i can use ufs flags field for that bit and chflags command. When i catch up situations of unlinking file, truncaing its size, i bzero unused blocks. While unlinking i found strange thing. I'm deleting blocks sequently from low blkno to high. If i change this sequence back to front (?) i've go no bzero'ed blocks at all. Maybe there is some other way of wiping blocks? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message