Subject: NetBSD Security Advisory 2006-024: systrace(4) integer overflow
To: None <netbsd-announce@NetBSD.org>
From: NetBSD Security-Officer <email@example.com>
Date: 11/27/2006 23:03:49
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NetBSD Security Advisory 2006-024
Topic: systrace(4) integer overflow
Version: NetBSD-current: source prior to October 6, 2006
NetBSD 3.1: not affected
NetBSD 3.0.2: not affected
NetBSD 3.0.1: affected
NetBSD 3.0: affected
NetBSD 2.1: affected
NetBSD 2.0.*: affected
NetBSD 2.0: affected
Severity: Local privilege escalation and denial of service
Fixed: NetBSD-current: October 6, 2006
NetBSD-3-0 branch: October 16, 2006
NetBSD-3 branch: October 16, 2006
NetBSD-2-1 branch: November 19, 2006
NetBSD-2-0 branch: November 19, 2006
NetBSD-2 branch: November 19, 2006
An integer overflow in systrace(4) can potentially lead to a local
denial of service and/or privilege escalation.
This vulnerability has been assigned CVE reference CVE-2006-5218.
A check for integer overflow is missing in the kernel component of systrace.
The problem is located in the "systrace_preprepl()" function.
The vulnerability can be triggered by passing a large (or negative) integer
value to a systrace ioctl().
Solutions and Workarounds
A possible solution is to disable systrace by commenting out the
"options SYSTRACE" line in your kernel configuration file. You
will need to re-compile and install the new kernel for the change
to become effective on reboot.
For all NetBSD versions, you need to obtain fixed kernel sources,
rebuild and install the new kernel, and reboot the system.
The fixed source may be obtained from the NetBSD CVS repository.
The following instructions briefly summarise how to upgrade your
kernel. In these instructions, replace:
ARCH with your architecture (from uname -m), and
KERNCONF with the name of your kernel configuration file.
To update from CVS, re-build, and re-install the kernel:
# cd src
# cvs update sys/sys/systrace.h \
# ./build.sh kernel=KERNCONF
# mv /netbsd /netbsd.old
# cp sys/arch/ARCH/compile/obj/KERNCONF/netbsd /netbsd
# shutdown -r now
For more information on how to do this, see:
Chris Evans is credited with the discovery of this issue.
2006-11-27 Initial release
Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at
Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.org/ and http://www.NetBSD.org/Security/.
Copyright 2006, The NetBSD Foundation, Inc. All Rights Reserved.
Redistribution permitted only in full, unmodified form.
$NetBSD: NetBSD-SA2006-024.txt,v 1.3 2006/11/27 20:14:45 adrianp Exp $
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