7e3734256c
- Fix paths in SA-16:03 for 'make sysent'. - SA-16:04 doesn't need 'make sysent'. Noticed by: Robert Ames <robertames hotmail.com>
141 lines
5.1 KiB
Text
141 lines
5.1 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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=============================================================================
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FreeBSD-SA-16:04.linux Security Advisory
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The FreeBSD Project
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Topic: Linux compatibility layer setgroups(2) system call
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vulnerability
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Category: core
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Module: kernel
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Announced: 2016-01-14
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Credits: Dmitry Chagin
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Affects: All supported versions of FreeBSD
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Corrected: 2016-01-14 09:11:42 UTC (stable/10, 10.2-STABLE)
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2016-01-14 09:10:46 UTC (releng/10.2, 10.2-RELEASE-p9)
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2016-01-14 09:11:16 UTC (releng/10.1, 10.1-RELEASE-p26)
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2016-01-14 09:11:48 UTC (stable/9, 9.3-STABLE)
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2016-01-14 09:11:26 UTC (releng/9.3, 9.3-RELEASE-p33)
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CVE Name: CVE-2016-1881
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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:https://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. The support is
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provided on amd64 and i386 machines.
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II. Problem Description
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A programming error in the Linux compatibility layer setgroups(2) system
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call can lead to an unexpected results, such as overwriting random kernel
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memory contents.
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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 a supported FreeBSD stable or
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release / security branch (releng) dated after the correction date.
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Reboot the system or unload and reload the linux.ko kernel module.
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2) To update your vulnerable system via a binary patch:
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Systems running a RELEASE version of FreeBSD on the i386 or amd64
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platforms can be updated via the freebsd-update(8) utility:
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# freebsd-update fetch
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# freebsd-update install
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Reboot the system or unload and reload the linux.ko kernel module.
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3) To update your vulnerable system via a source code patch:
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The following patches have been verified to apply to the applicable
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FreeBSD release branches.
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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 https://security.FreeBSD.org/patches/SA-16:04/linux.patch
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# fetch https://security.FreeBSD.org/patches/SA-16:04/linux.patch.asc
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# gpg --verify linux.patch.asc
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b) Apply the patch. 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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c) Recompile your kernel as described in
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<URL:https://www.FreeBSD.org/handbook/kernelconfig.html>.
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Reboot the system or unload and reload the linux.ko kernel module.
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VI. Correction details
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The following list contains the correction revision numbers for each
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affected branch.
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Branch/path Revision
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- -------------------------------------------------------------------------
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stable/9/ r293898
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releng/9.3/ r293896
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stable/10/ r293897
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releng/10.1/ r293894
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releng/10.2/ r293893
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- -------------------------------------------------------------------------
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To see which files were modified by a particular revision, run the
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following command, replacing NNNNNN with the revision number, on a
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machine with Subversion installed:
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# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base
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Or visit the following URL, replacing NNNNNN with the revision number:
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<URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>
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VII. References
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<URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-1881>
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The latest revision of this advisory is available at
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<URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-16:04.linux.asc>
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