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ESB-2006.0077 -- [FreeBSD] -- Local kernel memory disclosure

Date: 27 January 2006

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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                        ESB-2006.0077 -- [FreeBSD]
                      Local kernel memory disclosure
                              27 January 2006

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           kmem
Publisher:         FreeBSD
Operating System:  FreeBSD
Impact:            Access Privileged Data
Access:            Existing Account
CVE Names:         CVE-2006-0380 CVE-2006-0379

Original Bulletin: 
  ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:06.kmem.asc

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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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NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/render.html?cid=1980

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

        http://www.auscert.org.au/render.html?it=3192

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================

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