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Home » Security Advisories» FreeBSD » Texindex temp file privilege escalation #2

Texindex temp file privilege escalation #2

This updated advisory provides corrected instructions for rebuilding texindex.

  • Vendor: FreeBSD
  • Vendor ID: SA-06:01.texindex:2
  • Date: January 11, 2006


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FreeBSD-SA-06:01.texindex Security Advisory
The FreeBSD Project

Topic: Texindex temporary file privilege escalation

Category: contrib
Module: texinfo
Announced: 2006-01-11
Credits: Frank Lichtenheld
Affects: All FreeBSD releases.
Corrected: 2006-01-11 08:02:16 UTC (RELENG_6, 6.0-STABLE)
2006-01-11 08:03:18 UTC (RELENG_6_0, 6.0-RELEASE-p2)
2006-01-11 08:03:55 UTC (RELENG_5, 5.4-STABLE)
2006-01-11 08:04:33 UTC (RELENG_5_4, 5.4-RELEASE-p9)
2006-01-11 08:05:54 UTC (RELENG_5_3, 5.3-RELEASE-p24)
2006-01-11 08:06:47 UTC (RELENG_4, 4.11-STABLE)
2006-01-11 08:07:18 UTC (RELENG_4_11, 4.11-RELEASE-p14)
2006-01-11 08:08:08 UTC (RELENG_4_10, 4.10-RELEASE-p20)
CVE Name: CAN-2005-3011

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit
.

0. Revision History.

v1.0 2006-01-11 Initial release.
v1.1 2006-01-11 Corrected instructions for rebuilding texindex.

I. Background

TeX is a document typesetting system which is popular in the mathematics,
physics, and computer science realms because of its ability to typeset
complex mathematical formulas. texindex(1) is a utility which is often
used to generate a sorted index of a TeX file.

II. Problem Description

The "sort_offline" function used by texindex(1) employs the "maketempname"
function, which produces predictable file names and fails to validate that
the paths do not exist.

III. Impact

These predictable temporary file names are problematic because they
allow an attacker to take advantage of a race condition in order to
execute a symlink attack, which could enable them to overwrite files
on the system in the context of the user running the texindex(1) utility.

IV. Workaround

No workaround is available, but the problematic code is only executed
if the input file being processed is 500kB or more in length; as a
result, users working with documents of less than several hundred pages
are very unlikely to be affected.

V. Solution

Perform one of the following:

1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_0, RELENG_5_4, 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, 5.3, 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 4.x and 5.x]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:01/texindex5x.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:01/texindex5x.patch.asc

[FreeBSD 6.x]
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:01/texindex.patch
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-06:01/texindex.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/gnu/usr.bin/texinfo/libtxi
# make obj && make depend && make
# cd /usr/src/gnu/usr.bin/texinfo/texindex
# make obj && make depend && make && make install

VI. Correction details

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

Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_4
contrib/texinfo/util/texindex.c 1.1.1.3.2.4
RELENG_4_11
src/UPDATING 1.73.2.91.2.15
src/sys/conf/newvers.sh 1.44.2.39.2.18
contrib/texinfo/util/texindex.c 1.1.1.3.2.3.6.1
RELENG_4_10
src/UPDATING 1.73.2.90.2.21
src/sys/conf/newvers.sh 1.44.2.34.2.22
contrib/texinfo/util/texindex.c 1.1.1.3.2.3.4.1
RELENG_5
contrib/texinfo/util/texindex.c 1.1.1.7.4.1
RELENG_5_4
src/UPDATING 1.342.2.24.2.18
src/sys/conf/newvers.sh 1.62.2.18.2.14
contrib/texinfo/util/texindex.c 1.1.1.7.8.1
RELENG_5_3
src/UPDATING 1.342.2.13.2.27
src/sys/conf/newvers.sh 1.62.2.15.2.29
contrib/texinfo/util/texindex.c 1.1.1.7.6.1
RELENG_6
contrib/texinfo/util/texindex.c 1.1.1.8.2.1
RELENG_6_0
src/UPDATING 1.416.2.3.2.7
src/sys/conf/newvers.sh 1.69.2.8.2.3
contrib/texinfo/util/texindex.c 1.1.1.8.4.1
- -------------------------------------------------------------------------

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-3011

The latest revision of this advisory is available at
ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:01.texindex.asc
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