SecurityTracker.com
    Home    |    View Topics    |    Search    |    Contact Us    |   

SecurityTracker
Archives


 


Category:   OS (UNIX)  >   NetBSD Vendors:   NetBSD
NetBSD if_bridge() May Disclose Portions of Kernel Memory to Local Users
SecurityTracker Alert ID:  1015846
SecurityTracker URL:  http://securitytracker.com/id/1015846
CVE Reference:   GENERIC-MAP-NOMATCH   (Links to External Site)
Date:  Mar 30 2006
Impact:   Disclosure of system information, Disclosure of user information
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): 1.6, 2.0, 2.1, 3.0
Description:   A vulnerability was reported in NetBSD in the bridge(4) implementation. A local user can view portions of kernel memory.

The if_bridge(4) code does not properly initialize stack memory used to temporarily store ioctl(2) request results. As a result, the calling process may be able to access portions of kernel stack memory.

Only a small number of bytes is exposed.

Xin LI reported this vulnerability.

Impact:   A local user can view portions of kernel stack memory.
Solution:   The vendor has issued a fix. The vendor's advisory is available at:

ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2006-005.txt.asc

Vendor URL:  www.netbsd.org/ (Links to External Site)
Cause:   Access control error

Message History:   None.


 Source Message Contents

Subject:  NetBSD Security Advisory 2006-005: bridge memory disclosure


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


		 NetBSD Security Advisory 2006-005
		 =================================

Topic:		bridge memory disclosure

Version:	NetBSD-current:	source prior to January 17, 2006
		NetBSD 3.0:	affected
		NetBSD 2.1:	affected
		NetBSD 2.0.*:	affected
		NetBSD 2.0:	affected
		NetBSD 1.6.*:	affected
		NetBSD 1.6:	affected

Severity:	Kernel sensitive information can be disclosed

Fixed:		NetBSD-current:		January 17, 2006
		NetBSD-3-0 branch:	February 12, 2006
						(3.0.1 will include the fix)
		NetBSD-3   branch:	February 12, 2006
		NetBSD-2-1 branch:	February 12, 2006
						(2.1.1 will include the fix)
		NetBSD-2-0 branch:	February 12, 2006
						(2.0.4 will include the fix)
		NetBSD-2   branch:	February 12, 2006

Abstract
========

An information disclosure issue exists in if_bridge(4) code.

Technical Details
=================

The bridge(4) ioctl(2) calls did not zero out the stack memory used
to temporarily store the results of the ioctl(2) requests before
copying them back to the requesting process. Thus portions of the
kernel stack memory could be exposed to the calling process. The
impact of this is minor since:

	1. the number of bytes exposed is small
	2. the location and therefore the contents cannot be controlled 
	   by the calling process and 
	3. the buffer is partially overwritten by the results

Solutions and Workarounds
=========================

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 -d -P sys/net/if_bridge.c
	# ./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:

   http://www.NetBSD.org/guide/en/chap-kernel.html


Thanks To
=========

Xin LI for notification and the initial fixes.
Christos Zoulas for implementing the fixes.


Revision History
================

	2006-03-29	Initial release


More Information
================

Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at 
  ftp://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2006-005.txt.asc

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-SA2006-005.txt,v 1.8 2006/03/29 11:14:28 adrianp Exp $

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.2 (NetBSD)

iQCVAwUBRCsC8z5Ru2/4N2IFAQI7LwP6A2xNHvoHx92Md1aBBcQ9s46KlbaemaYM
UqmxUz6nlgYSvHq6/DYdFvNxxf2J/2dXNmhkSPdr5eHqXQ+uXIa0nt0WEmR6tVYY
JlrK/HUOkaIQulokGtS3h1fpqgT0UFI4ZkbVd2BMU3zkV+DvfdoVh2+RqgkijpfJ
5DfSETl8gcQ=
=obSz
-----END PGP SIGNATURE-----

 
 


Go to the Top of This SecurityTracker Archive Page





Home   |    View Topics   |    Search   |    Contact Us

This web site uses cookies for web analytics. Learn More

Copyright 2021, SecurityGlobal.net LLC