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=============================================================================
FreeBSD-SA-08:02.libc Security Advisory
The FreeBSD Project

Topic: inet_network() buffer overflow

Category: core
Module: libc
Announced: 2008-01-14
Credits: Bjoern A. Zeeb and Nate Eldredge
Affects: FreeBSD 6.2
Corrected: 2008-01-14 22:57:45 UTC (RELENG_7, 7.0-PRERELEASE)
2008-01-14 22:55:54 UTC (RELENG_7_0, 7.0-RC2)
2008-01-14 22:56:05 UTC (RELENG_6, 6.3-PRERELEASE)
2008-01-14 22:56:18 UTC (RELENG_6_3, 6.3-RELEASE)
2008-01-14 22:56:44 UTC (RELENG_6_2, 6.2-RELEASE-p10)
CVE Name: CVE-2008-0122

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/&gt;.

I. Background

The resolver is the part of libc that resolves hostnames (example.com) to
internet protocol (IP) addresses (192.0.2.1) and vice versa.

The inet_network() function returns an in_addr_t representing the network
address of the IP address given to inet_network() as a character string in
the dot-notation.

II. Problem Description

An off-by-one error in the inet_network() function could lead to memory
corruption with certain inputs.

III. Impact

For programs which passes untrusted data to inet_network(), an
attacker may be able to overwrite a region of memory with user defined
data by causing specially crafted input to be passed to
inet_network().

Depending on the region of memory the attacker is able to overwrite,
this might lead to a denial of service or potentially code execution
in the program using inet_network().

IV. Workaround

No workaround is available.

V. Solution

Perform one of the following:

1) Upgrade your vulnerable system to 7.0-PRERELEASE, or 6-STABLE, or
to the, RELENG_7_0, RELENG_6_3, or RELENG_6_2 security branch dated
after the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 7.0, 6.3,
or 6.2 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/SA-08:02/libc.patch

fetch http://security.FreeBSD.org/patches/SA-08:02/libc.patch.asc

b) Execute the following commands as root:

cd /usr/src

patch < /path/to/patch

c) Recompile the operating system as described in
<URL: http://www.freebsd.org/handbook/makeworld.html&gt; 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
src/lib/libc/inet/inet_network.c 1.2.2.2
RELENG_6_3
src/UPDATING 1.416.2.37.2.3
src/sys/conf/newvers.sh 1.69.2.15.2.3
src/lib/libc/inet/inet_network.c 1.2.2.1.4.1
RELENG_6_2
src/UPDATING 1.416.2.29.2.13
src/sys/conf/newvers.sh 1.69.2.13.2.13
src/lib/libc/inet/inet_network.c 1.2.2.1.2.1
RELENG_7
src/lib/libc/inet/inet_network.c 1.4.2.1
RELENG_7_0
src/UPDATING 1.507.2.3.2.1
src/sys/conf/newvers.sh 1.72.2.5.2.2
src/lib/libc/inet/inet_network.c 1.4.4.1

---

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-0122

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-08:02.libc.asc
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