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FreeBSD-SA-05:08.kmem                                       Security Advisory
                                                          The FreeBSD Project

Topic:          Local kernel memory disclosure

Category:       core
Module:         sys
Announced:      2005-05-06
Credits:        Christian S.J. Peron
                Uwe Doering
Affects:        All FreeBSD releases prior to 5.4-RELEASE
Corrected:      2005-05-08 10:19:37 UTC (RELENG_5, 5.4-STABLE)
                2005-05-07 03:58:26 UTC (RELENG_5_4, 5.4-RELEASE)
                2005-05-08 10:23:52 UTC (RELENG_5_3, 5.3-RELEASE-p14)
                2005-05-08 10:26:42 UTC (RELENG_4, 4.11-STABLE)
                2005-05-08 10:29:54 UTC (RELENG_4_11, 4.11-RELEASE-p8)
                2005-05-08 10:35:56 UTC (RELENG_4_10, 4.10-RELEASE-p13)
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/>.

0.   Revision History

v1.0 2005-05-06  Initial release.
v1.1 2005-05-07  Updated patch to include related issues reported by
                 Uwe Doering.

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/kmem4x.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem4x.patch.asc

[FreeBSD 5.x]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem5x.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-05:08/kmem5x.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_4
  src/sys/kern/uipc_usrreq.c                                    1.54.2.11
  src/sys/kern/vfs_subr.c                                      1.249.2.32
  src/sys/net/if_mib.c                                            1.8.2.3
  src/sys/netinet/ip_divert.c                                    1.42.2.8
  src/sys/netinet/raw_ip.c                                      1.64.2.20
  src/sys/netinet/tcp_subr.c                                    1.73.2.34
  src/sys/netinet/udp_usrreq.c                                  1.64.2.20
RELENG_4_11
  src/UPDATING                                              1.72.2.91.2.9
  src/sys/conf/newvers.sh                                  1.44.2.39.2.12
  src/sys/kern/uipc_usrreq.c                                1.54.2.10.8.1
  src/sys/kern/vfs_subr.c                                  1.249.2.31.6.1
  src/sys/net/if_mib.c                                        1.8.2.2.2.1
  src/sys/netinet/ip_divert.c                                1.42.2.7.2.1
  src/sys/netinet/raw_ip.c                                  1.64.2.19.2.1
  src/sys/netinet/tcp_subr.c                                1.73.2.33.4.1
  src/sys/netinet/udp_usrreq.c                              1.64.2.19.6.1
RELENG_4_10
  src/UPDATING                                             1.73.2.90.2.14
  src/sys/conf/newvers.sh                                  1.44.2.34.2.15
  src/sys/kern/uipc_usrreq.c                                1.54.2.10.6.1
  src/sys/kern/vfs_subr.c                                  1.249.2.31.4.1
  src/sys/net/if_mib.c                                       1.8.2.1.16.2
  src/sys/netinet/ip_divert.c                                1.42.2.6.6.1
  src/sys/netinet/raw_ip.c                                  1.64.2.18.4.1
  src/sys/netinet/tcp_subr.c                                1.73.2.33.2.1
  src/sys/netinet/udp_usrreq.c                              1.64.2.19.4.1
RELENG_5
  src/sys/kern/subr_bus.c                                       1.156.2.7
  src/sys/kern/uipc_usrreq.c                                   1.138.2.14
  src/sys/kern/vfs_subr.c                                       1.522.2.5
  src/sys/net/if_mib.c                                           1.13.4.2
  src/sys/netinet/ip_divert.c                                    1.98.2.3
  src/sys/netinet/raw_ip.c                                      1.142.2.5
  src/sys/netinet/tcp_subr.c                                   1.201.2.18
  src/sys/netinet/udp_usrreq.c                                  1.162.2.8
RELENG_5_4
  src/UPDATING                                             1.342.2.24.2.9
  src/sys/kern/subr_bus.c                                   1.156.2.5.2.1
  src/sys/kern/uipc_usrreq.c                               1.138.2.13.2.1
  src/sys/kern/vfs_subr.c                                   1.522.2.4.2.1
  src/sys/net/if_mib.c                                       1.13.4.1.2.1
  src/sys/netinet/ip_divert.c                                1.98.2.2.2.1
  src/sys/netinet/raw_ip.c                                  1.142.2.4.2.1
  src/sys/netinet/tcp_subr.c                               1.201.2.15.2.1
  src/sys/netinet/udp_usrreq.c                              1.162.2.7.2.1
RELENG_5_3
  src/UPDATING                                            1.342.2.13.2.17
  src/sys/conf/newvers.sh                                  1.62.2.15.2.19
  src/sys/kern/subr_bus.c                                   1.156.2.2.2.1
  src/sys/kern/uipc_usrreq.c                                1.138.2.2.2.2
  src/sys/kern/vfs_subr.c                                   1.522.2.1.2.1
  src/sys/net/if_mib.c                                           1.13.6.1
  src/sys/netinet/ip_divert.c                                    1.98.4.1
  src/sys/netinet/raw_ip.c                                  1.142.2.2.2.1
  src/sys/netinet/tcp_subr.c                                1.201.2.1.2.2
  src/sys/netinet/udp_usrreq.c                              1.162.2.3.2.1
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The latest revision of this advisory is available at ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-05:08.kmem.asc
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