123 lines
4.3 KiB
Text
123 lines
4.3 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-12:08.linux Security Advisory
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The FreeBSD Project
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Topic: Linux compatibility layer input validation error
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Category: core
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Module: kernel
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Announced: 2012-11-22
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Credits: Mateusz Guzik
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Affects: All supported versions of FreeBSD.
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Corrected: 2012-11-22 23:15:38 UTC (RELENG_7, 7.4-STABLE)
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2012-11-22 22:52:15 UTC (RELENG_7_4, 7.4-RELEASE-p11)
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2012-11-22 22:52:15 UTC (RELENG_8, 8.3-STABLE)
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2012-11-22 22:52:15 UTC (RELENG_8_3, 8.3-RELEASE-p5)
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2012-11-22 22:52:15 UTC (RELENG_9, 9.1-PRERELEASE)
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2012-11-22 22:52:15 UTC (RELENG_9_0, 9.0-RELEASE-p5)
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2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC1-p1)
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2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC2-p1)
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2012-11-22 22:52:15 UTC (RELENG_9_1, 9.1-RC3-p1)
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CVE Name: CVE-2012-4576
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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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FreeBSD is binary-compatible with the Linux operating system through a
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loadable kernel module/optional kernel component.
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II. Problem Description
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A programming error in the handling of some Linux system calls may
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result in memory locations being accessed without proper validation.
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III. Impact
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It is possible for a local attacker to overwrite portions of kernel
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memory, which may result in a privilege escalation or cause a system
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panic.
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IV. Workaround
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No workaround is available, but systems not using the Linux binary
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compatibility layer are not vulnerable.
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The following command can be used to test if the Linux binary
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compatibility layer is loaded:
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# kldstat -m linuxelf
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V. Solution
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Perform one of the following:
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1) Upgrade your vulnerable system to 7-STABLE, 8-STABLE, or 9-STABLE,
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or to the RELENG_7_4, RELENG_8_3, RELENG_9_0, or RELENG_9_1 security
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branch dated after the correction date.
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2) To update your vulnerable system via a source code patch:
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The following patches have been verified to apply to FreeBSD 7.4,
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8.3, 9.0, and 9.1 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-12:08/linux.patch
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# fetch http://security.FreeBSD.org/patches/SA-12:08/linux.patch.asc
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b) Apply the patch.
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# cd /usr/src
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# patch < /path/to/patch
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c) Recompile your kernel as described in
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<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
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system.
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3) To update your vulnerable system via a binary patch:
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Systems running 7.4-RELEASE, 8.3-RELEASE, 9.0-RELEASE, 9.1-RC1,
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9.1-RC2, or 9.1-RC3 on the i386 or amd64 platforms can be updated via
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the freebsd-update(8) utility:
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# freebsd-update fetch
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# freebsd-update 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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Subversion:
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Branch/path Revision
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- -------------------------------------------------------------------------
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stable/7/ r243418
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releng/7.4/ r243417
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stable/8/ r243417
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releng/8.3/ r243417
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stable/9/ r243417
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releng/9.0/ r243417
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releng/9.1/ r243417
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- -------------------------------------------------------------------------
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VII. References
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-4576
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-12:08.linux.asc
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