Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261741AbUCGEPR (ORCPT ); Sat, 6 Mar 2004 23:15:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261747AbUCGEPR (ORCPT ); Sat, 6 Mar 2004 23:15:17 -0500 Received: from mta7.pltn13.pbi.net ([64.164.98.8]:58339 "EHLO mta7.pltn13.pbi.net") by vger.kernel.org with ESMTP id S261741AbUCGEPN (ORCPT ); Sat, 6 Mar 2004 23:15:13 -0500 Message-ID: <404AA1B2.4090500@matchmail.com> Date: Sat, 06 Mar 2004 20:14:42 -0800 From: Mike Fedyk User-Agent: Mozilla Thunderbird 0.5 (X11/20040209) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Pavel Machek CC: Jean-Luc Cooke , dean gaudet , James Morris , Christophe Saout , Carl-Daniel Hailfinger , Linux Kernel Mailing List , Andrew Morton Subject: DM for detecting bad disks was: dm-crypt, new IV and standards References: <20040220172237.GA9918@certainkey.com> <20040221164821.GA14723@certainkey.com> <20040303150647.GC1586@certainkey.com> <20040304150836.GE531@openzaurus.ucw.cz> In-Reply-To: <20040304150836.GE531@openzaurus.ucw.cz> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1326 Lines: 30 Pavel Machek wrote: > Hi! > > >>>>Well, CTR mode is not recommended for encrypted file systems because it is very >>>>easy to corrupt single bits, bytes, blocks, etc without an integrity check. >>>>If we add a MAC, then any mode of operation except ECB can be used for >>>>encrypted file systems. >>> >>>what does "easy to corrupt" mean? i haven't really seen disks generate >>>bit errors ever. this MAC means you'll need to write integrity data for >>>every real write. that really doesn't seem worth it... >> >>The difference between "_1,000,000" and "_8,000,000" is 1 bit. If an >>attacker knew enough about the layout of the filesystem (modify times on blocks, >>etc) they could flip a single bit and change your _1Mil purchase order >>approved by your boss to a _8Mil order. > > > Hmm... long time ago I created crc loop device to catch > faulty disks. If cryptoloop can do that for me... very good! Yes, a crc, or some other very low overhead DM target would be great for this. I haven't looked at DM too much. :( Does it already have something like this already? - 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/