Subject: NetBSD Security Advisory 2006-012: SIOCGIFALIAS ioctl may cause system crash
To: None <>
From: NetBSD Security-Officer <>
List: current-users
Date: 04/13/2006 03:32:12
Hash: SHA1

		 NetBSD Security Advisory 2006-012

Topic:		SIOCGIFALIAS ioctl may cause system crash

Version:	NetBSD-current:	source prior to September 28, 2005
		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:	Any local user can crash the system

Fixed:		NetBSD-current:		September 28, 2005
		NetBSD-3-0 branch:	April 02, 2006
						(3.0.1 will include the fix)
		NetBSD-3   branch:	April 02, 2006
		NetBSD-2-1 branch:	April 02, 2006
						(2.1.1 will include the fix)
		NetBSD-2-0 branch:	April 02, 2006
						(2.0.4 will include the fix)
		NetBSD-2 branch:	April 02, 2006
		NetBSD-1-6 branch:	April 02, 2006


A system crash can occur if a user attempts to gather information on a
non-existent alias of a network interface via the SIOCGIFALIAS ioctl.

Technical Details

A NULL dereference occurs in the kernel when the alias in question
was not located, rather than returning an error.  A socket on the
local machine is required.

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/netinet/in.c
	# ./ 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:

Thanks To

Sean Boudreau for PoC code and implementing the fixes.

Revision History

	2006-04-12	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

Information about NetBSD and NetBSD security can be found at and

Copyright 2006, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2006-012.txt,v 1.6 2006/04/12 22:09:50 adrianp Exp $

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