FreeBSD Security Advisory FreeBSD-SA-16:10.linux

Fabricante: FreeBSD
Fecha: 27/01/2016
Identificador: FreeBSD-SA-16:10.linux
FreeBSD Security Advisory FreeBSD-SA-16:10.linux
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-16:10.linux Security Advisory The FreeBSD Project Topic: Linux compatibility layer issetugid(2) system call vulnerability Category: core Module: kernel Announced: 2016-01-27 Credits: Isaac Dunham, Brent Cook, Warner Losh Affects: All supported versions of FreeBSD. Corrected: 2016-01-27 07:28:55 UTC (stable/10, 10.2-STABLE) 2016-01-27 07:41:31 UTC (releng/10.2, 10.2-RELEASE-p11) 2016-01-27 07:41:31 UTC (releng/10.1, 10.1-RELEASE-p28) 2016-01-27 07:34:23 UTC (stable/9, 9.3-STABLE) 2016-01-27 07:42:11 UTC (releng/9.3, 9.3-RELEASE-p35) CVE Name: CVE-2016-1883 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit . I. Background FreeBSD is binary-compatible with the Linux operating system through a loadable kernel module/optional kernel component. The support is provided on amd64 and i386 machines. II. Problem Description A programming error in the Linux compatibility layer could cause the issetugid(2) system call to return incorrect information. III. Impact If an application relies on output of the issetugid(2) system call and that information is incorrect, this could lead to a privilege escalation. IV. Workaround No workaround is available, but systems not using the Linux binary compatibility layer are not vulnerable. The following command can be used to test if the Linux binary compatibility layer is loaded: # kldstat -m linuxelf V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. Reboot the system or unload and reload the linux.ko kernel module. 2) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install Reboot the system or unload and reload the linux.ko kernel module. 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. # fetch https://security.FreeBSD.org/patches/SA-16:10/linux.patch # fetch https://security.FreeBSD.org/patches/SA-16:10/linux.patch.asc # gpg --verify linux.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in and reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/9/ r294903 releng/9.3/ r294905 stable/10/ r294901 releng/10.1/ r294904 releng/10.2/ r294904 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.8 (FreeBSD) iQIcBAEBCgAGBQJWqHmfAAoJEO1n7NZdz2rnsr0QAJtM4C+IgRcRHdNGL7vXp1NP u3sFyktcRGCR0p+lMOaFYPp/Vmu09NglhcaxYFbk4WONVSnZKOuiWsjOL9by/eof 77i8bXINlB/8Pp+34KpxDtz5wR3jVAApaL8xvS+/DaKj3RdQ63RrHgtQRTAk+VSO ISAXxF2U/XAcRlmBQ3oOtqeHads6M1LNG/D/I0FgpU2G17QoUpfa+AvOkS1wBw7d mdcnC4NDKKx3QnyD0FTrh4z444PwvE3IQ7OSm7VX4/oOZdH+CC9coLCV1BXALrfA WVmaUMDy8bWiv7JMsda2xl4KhcEx2Y0UN2hGYdMZJubqYcnUknMimW3b2fhsfgl1 UaQDD6xv9I4xZqo1NHh4/WiH33PvOmM+U0E6IMb5hTUbfSd0mXOn4yzTP5gJxe4h fPk5ZUj/HTKx6C8ERMknTDdn+ZrLLlQJAoDbipPZkRBMcsgvRYGjKquBnrW9N0z2 BUtuLODg/GxMmkQXYV7mT08xw7YLvIbfSwGvlOd/k5hB/0KMTRLBFGd6vc2lZ+CL dseeK59vUK50Arua8qbg6AlOYc9Dga/XeQ753za0zEm7LOXzjr7jlBex/04ZxvE/ N4OTxNYlASk1cwBcoytZ8da3D7Vqh7vw7QmUR8lAb/x5ijR1QjCApji+yRupCEG+ PGHIMcxSGeBx7Drd1eBE =PyM5 -----END PGP SIGNATURE-----