Date: Fri, 8 Dec 2000 07:53:03 -0800 (PST) From: didier.poirot@sun.com To: freebsd-gnats-submit@FreeBSD.org Subject: i386/23380: newfs_msdos breaks the DOS partition table (and BSD label sector) Message-ID: <200012081553.eB8Fr3853015@freefall.freebsd.org> Resent-Message-ID: <200012081600.eB8G04c54728@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 23380 >Category: i386 >Synopsis: newfs_msdos breaks the DOS partition table (and BSD label sector) >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Dec 08 08:00:04 PST 2000 >Closed-Date: >Last-Modified: >Originator: Poirot >Release: 4.1 >Organization: Sun Microsystems >Environment: FreeBSD bongo 4.0-RELEASE FreeBSD 4.0-RELEASE #11: Fri Dec 8 16:37:27 CET 2000 dp@bongo:/usr/src/sys/compile/GENERIC i386 >Description: Installing a MSDOS filesystem with the newfs_msdos(1) utility in the first partition of the first slice (e.g /dev/ad0s1a) of a disk breaks the DOS partition table contained in the sector 0 of the disk (the MBR). Note: the partition 'a' must start at the beginning of the slice, e.g the oa# field of the disktab entry must be set to 0. The newfs_msdos utility writes to 'absolute' sector 0 of the disk, instead of writing to 'relative' sector 0 (relative to beginning of the slice, not of the disk). It also tries to write to 'absolute' sector 1 (which contain the BSD label), must access is denied by the system. >How-To-Repeat: 1. Using fdisk(1) create 1 slice( e.g ad0s1), starting at 0, type 165 2. Using disklabel, write a label to the disk slice mentionned above. This label should contain a partition starting at 0. 3. Use newfs_msdos on this partition (e.g /dev/ad0s1a). 4. Try to re-read the DOS partition table with fdisk. >Fix: The disktab entry used must not start at offset 0 in the slice, but say at 16. >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200012081553.eB8Fr3853015>