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FreeBSD-SA-09:17.freebsd-update                             Security Advisory
                                                          The FreeBSD Project

Topic:          Inappropriate directory permissions in freebsd-update(8)

Category:       core
Module:         usr.sbin
Announced:      2009-12-03
Credits:        KAMADA Ken'ichi
Affects:        All supported versions of FreeBSD.
Corrected:      2009-12-03 09:18:40 UTC (RELENG_8, 8.0-STABLE)
                2009-12-03 09:18:40 UTC (RELENG_8_0, 8.0-RELEASE-p1)
                2009-12-03 09:18:40 UTC (RELENG_7, 7.2-STABLE)
                2009-12-03 09:18:40 UTC (RELENG_7_2, 7.2-RELEASE-p5)
                2009-12-03 09:18:40 UTC (RELENG_7_1, 7.1-RELEASE-p9)
                2009-12-03 09:18:40 UTC (RELENG_6, 6.4-STABLE)
                2009-12-03 09:18:40 UTC (RELENG_6_4, 6.4-RELEASE-p8)
                2009-12-03 09:18:40 UTC (RELENG_6_3, 6.3-RELEASE-p14)

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

I.   Background

The freebsd-update(8) utility is used to fetch, install, and rollback
updates to the FreeBSD base system, and also to upgrade from one FreeBSD
release to another.

II.  Problem Description

When downloading updates to FreeBSD via 'freebsd-update fetch' or
'freebsd-update upgrade', the freebsd-update(8) utility copies currently
installed files into its working directory (/var/db/freebsd-update by
default) both for the purpose of merging changes to configuration files
and in order to be able to roll back installed updates.

The default working directory used by freebsd-update(8) is normally
created during the installation of FreeBSD with permissions which allow
all local users to see its contents, and freebsd-update(8) does not take
any steps to restrict access to files stored in said directory.

III. Impact

A local user can read files which have been updated by freebsd-update(8),
even if those files have permissions which would normally not allow users
to read them.  In particular, on systems which have been upgraded using
'freebsd-update upgrade', local users can read freebsd-update's backed-up
copy of the master password file.

IV.  Workaround

Set the permissions on the freebsd-update(8) working directory to not
allow unprivileged users to read said directory:

# chmod 0700 /var/db/freebsd-update

Note that if freebsd-update(8) is run using the '-d workdir' option, the
directory which should have its permissions adjusted will be different.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 6-STABLE, 7-STABLE or 8-STABLE,
or to the RELENG_8_0, RELENG_7_2, RELENG_7_1, RELENG_6_4, or
RELENG_6_3 security branch dated after the correction date.

2) To patch your present system:

The following patch has been verified to apply to FreeBSD 6.3, 6.4,
7.1, 7.2, and 8.0 systems.

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

# fetch https://security.FreeBSD.org/patches/SA-09:17/freebsd-update.patch
# fetch https://security.FreeBSD.org/patches/SA-09:17/freebsd-update.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/usr.sbin/freebsd-update
# make obj && make depend && make && make install
# chmod 0700 /var/db/freebsd-update

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

CVS:

Branch                                                           Revision
  Path
- -------------------------------------------------------------------------
RELENG_6
  src/usr.sbin/freebsd-update/freebsd-update.sh                  1.2.2.11
  src/etc/mtree/BSD.var.dist                                     1.71.2.4
RELENG_6_4
  src/UPDATING                                            1.416.2.40.2.12
  src/sys/conf/newvers.sh                                  1.69.2.18.2.14
  src/usr.sbin/freebsd-update/freebsd-update.sh              1.2.2.10.2.2
  src/etc/mtree/BSD.var.dist                                 1.71.2.3.6.2
RELENG_6_3
  src/UPDATING                                            1.416.2.37.2.19
  src/sys/conf/newvers.sh                                  1.69.2.15.2.18
  src/usr.sbin/freebsd-update/freebsd-update.sh               1.2.2.8.2.1
  src/etc/mtree/BSD.var.dist                                 1.71.2.3.4.1
RELENG_7
  src/usr.sbin/freebsd-update/freebsd-update.sh                   1.8.2.5
  src/etc/mtree/BSD.var.dist                                     1.75.2.1
RELENG_7_2
  src/UPDATING                                             1.507.2.23.2.8
  src/sys/conf/newvers.sh                                   1.72.2.11.2.9
  src/usr.sbin/freebsd-update/freebsd-update.sh               1.8.2.4.4.2
  src/etc/mtree/BSD.var.dist                                     1.75.8.2
RELENG_7_1
  src/UPDATING                                            1.507.2.13.2.12
  src/sys/conf/newvers.sh                                   1.72.2.9.2.13
  src/usr.sbin/freebsd-update/freebsd-update.sh               1.8.2.4.2.2
  src/etc/mtree/BSD.var.dist                                     1.75.6.2
RELENG_8
  src/usr.sbin/freebsd-update/freebsd-update.sh                  1.16.2.3
  src/etc/mtree/BSD.var.dist                                    1.75.10.2
RELENG_8_0
  src/UPDATING                                              1.632.2.7.2.4
  src/sys/conf/newvers.sh                                    1.83.2.6.2.4
  src/usr.sbin/freebsd-update/freebsd-update.sh              1.16.2.2.2.2
  src/etc/mtree/BSD.var.dist                                1.75.10.1.2.2
- -------------------------------------------------------------------------

Subversion:

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/6/                                                         r200054
releng/6.4/                                                       r200054
releng/6.3/                                                       r200054
stable/7/                                                         r200054
releng/7.2/                                                       r200054
releng/7.1/                                                       r200054
stable/8/                                                         r200054
releng/8.0/                                                       r200054
- -------------------------------------------------------------------------

VII. References

The latest revision of this advisory is available at
https://security.FreeBSD.org/advisories/FreeBSD-SA-09:17.freebsd-update.asc
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