From owner-freebsd-hackers Tue Nov 26 03:31:56 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id DAA27182 for hackers-outgoing; Tue, 26 Nov 1996 03:31:56 -0800 (PST) Received: from narcissus.ml.org (brosenga.st.pitzer.edu [134.173.120.201]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id DAA27177 for ; Tue, 26 Nov 1996 03:31:51 -0800 (PST) Received: (from ben@localhost) by narcissus.ml.org (8.7.5/8.7.3) id DAA01069; Tue, 26 Nov 1996 03:31:40 -0800 (PST) Date: Tue, 26 Nov 1996 03:31:39 -0800 (PST) From: Snob Art Genre To: Robert Nordier cc: "Jordan K. Hubbard" , grog@lemis.de, hackers@freebsd.org Subject: Re: A simple way to crash your system. In-Reply-To: <199611261049.MAA02308@eac.iafrica.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk On Tue, 26 Nov 1996, Robert Nordier wrote: > Jordan K. Hubbard wrote: > > > > - remove it and announce the fact on -announce. > > > > That won't last more than a week - people don't search the archives > > and memories are short. > > > > > - make it read-only (will this help?) > > > > It already is read-only by default if you mount it from the label > > editor. People change it back the minute they want to write on > > it. :-) > > > > I'm not sure what to do. Putting it into the release notes under a > > "STILL BROKEN" section seems also excessive.. :) > > FWIW, the table below represents a couple of months of collecting > data from users on -questions, who reported that the msdosfs had > seriously corrupted a UFS partition. > > DRIVE DOS START DOS END > cyl head sect || cyl head sect cyl head sect size > ------------------------------------------------------------------- > wd0 | 525 | 64 | 63 || 0 | 1 | 1 | 126 | 63 | 63 | 512001 > wd0 | 2099 | 64 | 63 || 0 | 1 | 1 | 189 | 63 | 63 | 766017 > same drive || 250 | 0 | 1 | 523 | 63 | 63 | 1104768 > wd0 | 788 | 64 | 63 || 0 | 1 | 1 | 787 | 63 | 63 | 3177153 > wd0 | 621 | 64 | 63 || 0 | 1 | 1 | 619 | 63 | 63 | 2499777 > wd0 | 525 | 64 | 63 || 0 | 1 | 1 | 523 | 63 | 63 | 2112705 > > *All* problems occurred with the DOS FS on a 64/63 IDE drive. FIPS > was not necessarily used. In one case, the corrupted UFS fs was > actually on another drive. > > Unless someone is aware of the problem being more general, it may > be worth patching the msdosfs code to (by default) refuse to access > DOS FSes with > 16 sectors per cluster on such drives. > > Or at least warn that 64/63 IDE setups are particularly vulnerable. > > -- > Robert Nordier > My drive was/is SCSI. Ben