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FreeBSD-SA-06:06.kmem                                       Security Advisory
                                                          The FreeBSD Project

Topic:          Local kernel memory disclosure

Category:       core
Module:         kernel
Announced:      2006-01-25
Credits:        Xin LI, Karl Janmar
Affects:        FreeBSD 5.4-STABLE and FreeBSD 6.0
Corrected:      2006-01-25 10:00:59 UTC (RELENG_6, 6.0-STABLE)
                2006-01-25 10:01:26 UTC (RELENG_6_0, 6.0-RELEASE-p4)
                2006-01-25 10:01:47 UTC (RELENG_5, 5.4-STABLE)
CVE Name:       CVE-2006-0379, CVE-2006-0380

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

I.   Background

The network sub-system commonly utilizes the ioctl(2) mechanism to pass
information regarding the current state and statistics of logical and
physical network devices.

II.  Problem Description

A buffer allocated from the kernel stack may not be completely
initialized before being copied to userland. [CVE-2006-0379]

A logic error in computing a buffer length may allow too much data to
be copied into userland. [CVE-2006-0380]

III. Impact

Portions of kernel memory may be disclosed to local users.  Such
memory might contain sensitive information, such as portions of the
file cache or terminal buffers. This information might be directly
useful, or it might be leveraged to obtain elevated privileges in
some way.  For example, a terminal buffer might include a user-entered
password.

IV.  Workaround

No workaround is available.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 5-STABLE or 6-STABLE, or to the
RELENG_6_0 security branch dated after the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 5.4 and 6.0
systems.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

[FreeBSD 5.4-STABLE and 6.0-STABLE]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:06/kmem.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:06/kmem.patch.asc

[FreeBSD 6.0-RELEASE]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:06/kmem60.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:06/kmem60.patch.asc

b) Apply the patch.

# cd /usr/src
# patch < /path/to/patch

c) Recompile your kernel as described in
<URL:http://www.freebsd.org/handbook/kernelconfig.html> 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_5
  src/sys/net/if_bridge.c                                        1.23.2.7
RELENG_6
  src/sys/net/if_bridge.c                                       1.11.2.24
RELENG_6_0
  src/UPDATING                                              1.416.2.3.2.9
  src/sys/conf/newvers.sh                                    1.69.2.8.2.5
  src/sys/net/if_bridge.c                                   1.11.2.12.2.4
  src/sys/net80211/ieee80211_ioctl.c                         1.25.2.3.2.2
- -------------------------------------------------------------------------

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0379
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0380

The latest revision of this advisory is available at
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:06.kmem.asc
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