Date: Wed, 10 Sep 2008 15:26:43 GMT From: Anatoly Borodin <anatoly.borodin@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/127270: fsck_msdosfs may crash Message-ID: <200809101526.m8AFQhC6082061@www.freebsd.org> Resent-Message-ID: <200809101530.m8AFU163041787@freefall.freebsd.org>
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>Number: 127270
>Category: misc
>Synopsis: fsck_msdosfs may crash
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Sep 10 15:30:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator: Anatoly Borodin
>Release: 7.1-PRERELEASE
>Organization:
>Environment:
FreeBSD hp.home 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Mon Sep 1 16:07:24 EEST 2008 anatoly.borodin@gmail.com:/usr/obj/usr/src/sys/GENERIC i386
>Description:
I use some FAT32 filesystem from a file image. It has errors, so I tried to check it with fsck_msdosfs /dev/md0 and got this:
** /dev/md0
Floating exception (core dumped)
I compiled fsck_msdosfs with debug information and found the faulty code block at /usr/src/sbin/fsck_msdosfs/boot.c:174
boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
/ boot->BytesPerSec
+ boot->ResSectors
+ boot->FATs * boot->FATsecs
- CLUST_FIRST * boot->SecPerClust;
It fails because in my case boot->BytesPerSec == 0. IMHO such condition should be checked, fixed in the FS, but not crashed.
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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