Subject: NetBSD Security Advisory 2006-026: Multiple denial of service issues
To: None <current-users@NetBSD.org>
From: NetBSD Security-Officer <email@example.com>
Date: 11/27/2006 22:59:31
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NetBSD Security Advisory 2006-026
Topic: Multiple denial of service issues
Version: NetBSD-current: source prior to October 23, 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: Denial of service issues ranging from resource leaks to
Fixed: NetBSD-current: October 23, 2006
NetBSD-3-0 branch: October 24, 2006
NetBSD-3 branch: October 24, 2006
NetBSD-2-1 branch: October 29, 2006
NetBSD-2-0 branch: October 29, 2006
NetBSD-2 branch: October 29, 2006
There are multiple denial of service issues that can result in resource
leaks or kernel panics.
* Dangling socket could exhaust local system resources
If a user supplies a bad 'name' or 'namelen' parameter to accept(2) this
could leave a dangling socket. If bad parameters were supplied and a
copyout(9) failed, the 'file' structure was cleaned up, but not the
associated socket. This could leave sockets in the CLOSE_WAIT state that
could never be closed.
* sendmsg(2) panic
On 64-bit architectures (e.g. amd64, sparc64, and alpha) sendmsg(2)
can cause a kernel panic, due to insufficient checks of the 'msg_controllen'
parameter in sendit().
* mount_procfs panic (with -o linux)
Trying to read '/emul/linux/proc/0/stat' on a procfs mounted with the 'linux'
option results in a kernel panic. The process in question has to no parent
process, resulting in a NULL dereference due to insufficient checks.
Solutions and Workarounds
* The sendmsg(2) panic only affects 64-bit systems.
* By default, procfs is not mounted with the 'linux' option, however it is
often enabled when using Linux emulation.
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/kern/uipc_syscalls.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:
The dangling socket issue was discovered and fixed by Sean Boudreau.
The sendmsg(2) panic was discovered and reported by Ryo Shimizu.
The mount_procfs panic was discovered and reported Nicolas Joly.
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-SA2006-026.txt,v 1.3 2006/11/27 20:14:45 adrianp Exp $
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