3571e53040
patches for easier mirroring, to eliminate a special copy, to make www.freebsd.org/security a full copy of security.freebsd.org and be eventually be the same. For now files are just sitting there. The symlinks are missing. Discussed on: www (repository location) Discussed with: simon (so)
129 lines
5.1 KiB
Text
129 lines
5.1 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-06:26.gtar Security Advisory
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The FreeBSD Project
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Topic: gtar name mangling symlink vulnerability
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Category: contrib
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Module: contrib_tar
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Announced: 2006-12-06
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Credits: Teemu Salmela
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Affects: FreeBSD 4.x and 5.x releases
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Corrected: 2006-12-06 09:16:17 UTC (RELENG_5, 5.5-STABLE)
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2006-12-06 09:16:41 UTC (RELENG_5_5, 5.5-RELEASE-p9)
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2006-12-06 09:17:09 UTC (RELENG_4, 4.11-STABLE)
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2006-12-06 09:18:02 UTC (RELENG_4_11, 4.11-RELEASE-p26)
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CVE Name: CVE-2006-6097
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For general information regarding FreeBSD Security Advisories,
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including descriptions of the fields above, security branches, and the
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following sections, please visit <URL:http://security.FreeBSD.org/>.
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I. Background
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GNU tar (gtar) is a utility to create and extract "tape archives",
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commonly known as tar files. GNU tar is included in FreeBSD 4.x as
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/usr/bin/tar, and in FreeBSD 5.x as /usr/bin/gtar.
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II. Problem Description
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Symlinks created using the "GNUTYPE_NAMES" tar extension can be
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absolute due to lack of proper sanity checks.
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III. Impact
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If an attacker can get a user to extract a specially crafted tar
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archive the attacker can overwrite arbitrary files with the
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permissions of the user running gtar. If file system permissions
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allow it, this may allow the attacker to overwrite important system
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file (if gtar is being run as root), or important user configuration
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files such as .tcshrc or .bashrc, which would allow the attacker to
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run arbitrary commands.
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IV. Workaround
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Use "bsdtar", which is the default tar implementation in FreeBSD 5.3
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and higher. For FreeBSD 4.x, bsdtar is available in the FreeBSD Ports
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Collection as ports/archivers/libarchive.
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V. Solution
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NOTE: The solution described below causes GNU tar to exit with an error
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when handling an archive with GNUTYPE_NAMES entries. The FreeBSD
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Security Team does not consider this to be a significant regression,
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since GNUTYPE_NAMES has not been used for many years and is not
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supported by other archival software such as libarchive(3); but the
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original (insecure) behaviour can be retained by running GNU tar with
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the newly added --allow-name-mangling option.
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Perform one of the following:
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1) Upgrade your vulnerable system to 4-STABLE, or 5-STABLE, or to the
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RELENG_5_5 or RELENG_4_11 security branch dated after the correction
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date.
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2) To patch your present system:
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The following patches have been verified to apply to FreeBSD 4.11 and
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5.5 systems.
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a) Download the relevant patch from the location below, and verify the
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detached PGP signature using your PGP utility.
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# fetch http://security.FreeBSD.org/patches/SA-06:26/gtar.patch
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# fetch http://security.FreeBSD.org/patches/SA-06:26/gtar.patch.asc
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b) Execute the following commands as root:
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# cd /usr/src
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# patch < /path/to/patch
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# cd /usr/src/gnu/usr.bin/tar
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# make obj && make depend && make && make install
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VI. Correction details
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The following list contains the revision numbers of each file that was
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corrected in FreeBSD.
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Branch Revision
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Path
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- -------------------------------------------------------------------------
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RELENG_4
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src/contrib/tar/src/common.h 1.2.2.2
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src/contrib/tar/src/extract.c 1.4.2.4
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src/contrib/tar/src/tar.c 1.2.2.3
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RELENG_4_11
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src/UPDATING 1.73.2.91.2.27
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src/sys/conf/newvers.sh 1.44.2.39.2.30
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src/contrib/tar/src/common.h 1.2.2.1.10.1
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src/contrib/tar/src/extract.c 1.4.2.3.8.1
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src/contrib/tar/src/tar.c 1.2.2.2.6.1
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RELENG_5
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src/contrib/tar/src/common.h 1.2.10.1
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src/contrib/tar/src/extract.c 1.6.8.1
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src/contrib/tar/src/tar.c 1.3.4.1
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RELENG_5_5
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src/UPDATING 1.342.2.35.2.9
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src/sys/conf/newvers.sh 1.62.2.21.2.11
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src/contrib/tar/src/common.h 1.2.22.1
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src/contrib/tar/src/extract.c 1.6.20.1
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src/contrib/tar/src/tar.c 1.3.16.1
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- -------------------------------------------------------------------------
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VII. References
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http://marc.theaimsgroup.com/?l=full-disclosure&m=116414883029517
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-6097
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-06:26.gtar.asc
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