-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ============================================================================= FreeBSD-SA-07:05.libarchive Security Advisory The FreeBSD Project Topic: Errors handling corrupt tar files in libarchive(3) Category: core Module: libarchive Announced: 2007-07-12 Credits: CPNI, CERT-FI, Tim Kientzle, Colin Percival Affects: FreeBSD 5.3 and later. Corrected: 2007-07-12 15:00:44 UTC (RELENG_6, 6.2-STABLE) 2007-07-12 15:01:14 UTC (RELENG_6_2, 6.2-RELEASE-p6) 2007-07-12 15:01:32 UTC (RELENG_6_1, 6.1-RELEASE-p18) 2007-07-12 15:01:42 UTC (RELENG_5, 5.5-STABLE) 2007-07-12 15:01:56 UTC (RELENG_5_5, 5.5-RELEASE-p14) CVE Name: CVE-2007-3641, CVE-2007-3644, CVE-2007-3645 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background The libarchive library provides a flexible interface for reading and writing streaming archive files such as tar and cpio, and has been the basis for FreeBSD's implementation of the tar(1) utility since FreeBSD 5.3. II. Problem Description Several problems have been found in the code used to parse the tar and pax interchange formats. These include entering an infinite loop if an archive prematurely ends within a pax extension header or if certain types of corruption occur in pax extension headers [CVE-2007-3644]; dereferencing a NULL pointer if an archive prematurely ends within a tar header immediately following a pax extension header or if certain other types of corruption occur in pax extension headers [CVE-2007-3645]; and miscomputing the length of a buffer resulting in a buffer overflow if yet another type of corruption occurs in a pax extension header [CVE-2007-3641]. III. Impact An attacker who can cause a corrupt archive of his choice to be parsed by libarchive, including by having "tar -x" (extract) or "tar -t" (list entries) run on it, can cause libarchive to enter an infinite loop, to core dump, or possibly to execute arbitrary code provided by the attacker. IV. Workaround No workaround is available, but systems which do not read tar or pax extension archives provided by untrusted sources are not vulnerable. Note that while these issues do not affect libarchive's ability to parse cpio, ISO9660, or zip format archives, libarchive automatically detects the format of an archive, so external metadata (e.g., a file name) is not sufficient to ensure that a file will not be parsed using the vulnerable tar/pax format parser. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to 5-STABLE, or 6-STABLE, or to the RELENG_6_2, RELENG_6_1, or RELENG_5_5 security branch dated after the correction date. 2) To patch your present system: The following patches have been verified to apply to FreeBSD 5.5, 6.1, and 6.2 systems. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch http://security.FreeBSD.org/patches/SA-07:05/libarchive.patch # fetch http://security.FreeBSD.org/patches/SA-07:05/libarchive.patch.asc b) Execute the following commands as root: # cd /usr/src # patch < /path/to/patch # cd /usr/src/lib/libarchive # make obj && make depend && make && make install # cd /usr/src/rescue # make obj && make depend && make && make install NOTE: On the amd64 platform, the above procedure will not update the lib32 (i386 compatibility) libraries. On amd64 systems where the i386 compatibility libraries are used, the operating system should instead be recompiled as described in VI. Correction details The following list contains the revision numbers of each file that was corrected in FreeBSD. Branch Revision Path - ------------------------------------------------------------------------- RELENG_5 src/lib/libarchive/archive_read_support_format_tar.c 1.26.2.8 RELENG_5_5 src/UPDATING 1.342.2.35.2.14 src/sys/conf/newvers.sh 1.62.2.21.2.16 src/lib/libarchive/archive_read_support_format_tar.c 1.26.2.7.2.1 RELENG_6 src/lib/libarchive/archive_read_support_format_tar.c 1.32.2.5 RELENG_6_2 src/UPDATING 1.416.2.29.2.9 src/sys/conf/newvers.sh 1.69.2.13.2.9 src/lib/libarchive/archive_read_support_format_tar.c 1.32.2.2.2.1 RELENG_6_1 src/UPDATING 1.416.2.22.2.20 src/sys/conf/newvers.sh 1.69.2.11.2.20 src/lib/libarchive/archive_read_support_format_tar.c 1.32.6.1 - ------------------------------------------------------------------------- VII. References http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3641 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3644 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3645 The latest revision of this advisory is available at http://security.FreeBSD.org/advisories/FreeBSD-SA-07:05.libarchive.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD4DBQFGlkN5FdaIBMps37IRAl/vAJ4vKkZ9eXBW4PPljvbgALUlAPdxCQCXRMzY 4hKO09Xhj1akwPufFXJS2w== =sRGA -----END PGP SIGNATURE-----