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FreeBSD-EN-06:02.net Errata Notice
The FreeBSD Project
Topic: Networking Issues
Category: core
Module: sys
Announced: 2006-08-28
Credits: Robert Watson, JINMEI Tatuya
Affects: FreeBSD 6.1-RELEASE
Corrected: 2006-08-28 07:31:11 UTC (RELENG_6_1, 6.1-RELEASE-p5)
For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit
.
I. Background
The FreeBSD kernel provides basic networking services, supporting the
IPv4 and IPv6 network protocols.
II. Problem Description
Several issues have been discovered in the networking code in the
FreeBSD 6.1 kernel. Specifically:
1. A pointer was not being checked for validity before being
dereferenced.
2. Some statistics-keeping code in the UMA memory allocator
erroneously counted certain types of successful memory allocations
as failures.
3. IPv6 neighbor discovery did not work correctly over point-to-point
links.
III. Impact
The impacts of these bugs are varied.
1. The pointer dereferencing issue could cause a kernel panic.
2. The memory statistics-keeping error could cause the kernel to
report an incorrect number of memory allocations that failed.
One symptom of this problem is a artificially high count of
"requests for mbufs denied" in the output from "netstat -m".
3. The IPv6 neighbor discovery bug could cause spurious warnings to
be generated when running IPv6 over point-to-point links. This
problem was particularly noticeable over gif(4) tunnels.
IV. Workaround
No workaround is available.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 6-STABLE, or to the RELENG_6_1
security branch dated after the correction date.
2) To patch your present system:
The following patch has been verified to apply to FreeBSD 6.1 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch http://security.FreeBSD.org/patches/EN-06:02/net.patch
# fetch http://security.FreeBSD.org/patches/EN-06:02/net.patch.asc
b) Apply the patch.
# cd /usr/src
# patch < /path/to/patch
c) Recompile your kernel as described in
and reboot the
system.
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_6_1
src/UPDATING 1.416.2.22.2.7
src/sys/conf/newvers.sh 1.69.2.11.2.7
src/sys/netinet/ip_output.c 1.242.2.8.2.1
src/sys/netinet6/in6.c 1.51.2.8.2.1
src/sys/netinet6/nd6.c 1.48.2.12.2.1
src/sys/vm/uma_core.c 1.119.2.15.2.1
- -------------------------------------------------------------------------
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-EN-06:02.net.asc
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