CVE Name:       CAN-2005-1406

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

In many parts of the FreeBSD kernel, names (of mount points, devices,
files, etc.) are manipulated as NULL-terminated strings, but are provided
to applications within fixed-length buffers.

II.  Problem Description

In several places, variable-length strings were copied into fixed-length
buffers without zeroing the unused portion of the buffer.

III. Impact

The previous contents of part of the fixed-length buffers will be
disclosed to applications.  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 4-STABLE or 5-STABLE, or to the
RELENG_5_3, RELENG_4_11, or RELENG_4_10 security branch dated after
the correction date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 4.10,
4.11, and 5.3 systems.

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

[FreeBSD 4.x]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem4.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem4.patch.asc

[FreeBSD 5.x]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem5.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem5.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                                                                                                    
                         Path                                                                            Revision
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