FreeBSD Security Advisory FreeBSD-SA-19:07.mds
15 May, 2019 by firstname.lastname@example.org | freebsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-19:07.mds Security Advisory The FreeBSD Project Topic: Microarchitectural Data Sampling (MDS) Category: core Module: kernel Announced: 2019-05-14 Credits: Refer to Intel's security advisory at the URL below for detailed acknowledgements. Affects: All supported versions of FreeBSD. Corrected: 2019-05-14 17:04:00 UTC (stable/12, 12.0-STABLE) 2019-05-15 13:44:27 UTC (releng/12.0, 12.0-RELEASE-p5) 2019-05-14 17:05:02 UTC (stable/11, 11.3-PRERELEASE) 2019-05-14 23:20:16 UTC (releng/11.2, 11.2-RELEASE-p10) CVE Name: CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. 0. Revision history v1.0 2019-05-14 Initial release. v1.1 2019-05-15 Fixed date on microcode update package. v1.2 2019-05-15 Userland startup microcode update details added. Add language specifying which manufacturers is affected. v1.3 2019-05-15 Minor quoting nit for the HT disable loader config. v2.0 2019-05-15 Rerelease 12.0-RELEASE patch as -p5 due to i386 panic bug. I. Background Modern processors make use of speculative execution, an optimization technique which performs some action in advance of knowing whether the result will actually be used. II. Problem Description On some Intel processors utilizing speculative execution a local process may be able to infer stale information from microarchitectural buffers to obtain a memory disclosure. III. Impact An attacker may be able to read secret data from the kernel or from a process when executing untrusted code (for example, in a web browser). IV. Workaround No workaround is available. Only Intel x86 based processors are affected. x86 processors from other manufacturers (eg, AMD) are not believed to be vulnerable. Systems with users or processors in different trust domains should disable Hyper-Threading by setting the machdep.hyperthreading_allowed tunable to 0: # echo 'machdep.hyperthreading_allowed=0' >> /boot/loader.conf # shutdown -r +10min "Security update" V. Solution Perform one of the following: Update CPU microcode, upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, evaluate mitigation and Hyper Threading controls, and reboot the system. New CPU microcode may be available in a BIOS update from your system vendor, or by installing the devcpu-data package or sysutils/devcpu-data port. Ensure that the BIOS update or devcpu-data package is dated after 2019-05-14. If using the package or port the Intel microcode update can be applied at boot time (only on FreeBSD 12 and later) by adding the following lines to the system's /boot/loader.conf: cpu_microcode_load="YES" cpu_microcode_name="/boot/firmware/intel-ucode.bin" To automatically load microcode during userland startup (supported on all FreeBSD versions), add the following to /etc/rc.conf: microcode_update_enable="YES" 1) 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 Follow additional details under "Mitigation Configuration" below. 2) 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. [*** v2.0 NOTE *** Only applies to 12.0-RELEASE ***] Due to an error in the 12.0-RELEASE affecting the i386 architecture, a new set of patches is being released. If your 12.0-RELEASE sources are not yet patched using the initially published patch, then you need to apply the mds.12.0.patch. If your sources are already updated, or patched with the patch from the initial advisory, then you need to apply the incremental patch, named mds.12.0.p4p5.patch [FreeBSD 12.0-STABLE] # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12-stable.patch # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12-stable.patch.asc # gpg --verify mds.12-stable.patch.asc [FreeBSD 12.0-RELEASE, not patched with initial SA-19:07.mds patch] # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12.0.patch # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12.0.patch.asc # gpg --verify mds.12.0.patch.asc [FreeBSD 12.0-RELEASE, patched with initial SA-19:07.mds patch] # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12.0.p4p5.patch # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.12.0.p4p5.patch.asc # gpg --verify mds.12.0.p4p5.patch.asc [FreeBSD 11.3-PRERELEASE] # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.11-stable.patch # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.11-stable.patch.asc # gpg --verify mds.11-stable.patch.asc [FreeBSD 11.2-RELEASE] # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.11.2.patch # fetch https://security.FreeBSD.org/patches/SA-19:07/mds.11.2.patch.asc # gpg --verify mds.11.2.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 <URL:https://www.FreeBSD.org/handbook/kernelconfig.html>. Mitigation Configuration Systems with users, processes, or virtual machines in different trust domains should disable Hyper-Threading by setting the machdep.hyperthreading_allowed tunable to 0: # echo machdep.hyperthreading_allowed=0 >> /boot/loader.conf To activate the MDS mitigation set the hw.mds_disable sysctl. The settings are: 0 - mitigation disabled 1 - VERW instruction (microcode) mitigation enabled 2 - Software sequence mitigation enabled (not recommended) 3 - Automatic VERW or Software selection Automatic mode uses the VERW instruction if supported by the CPU / microcode, or software sequences if not. To enable automatic mode at boot: # echo hw.mds_disable=3 >> /etc/sysctl.conf Reboot the system: # shutdown -r +10min "Security update" Check the mitigation status: # sysctl hw.mds_disable_state hw.mds_disable_state: software Silvermont VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/12/ r347567 releng/12.0/ r347632 stable/11/ r347568 releng/11.2/ r347595 - ------------------------------------------------------------------------- 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: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00233.html> <URL:https://www.intel.com/content/www/us/en/architecture-and-technology/mds.html> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-19:07.mds.asc> -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAlzciUJfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cKc2w//UxEu2JWDEJnpGuYv/Hh+PAEsWjzG2mCuFmriF7//deJTbwWybJk0DXhU n6HCdw47nG/uVaeVOw921BRpJMK9bqpqr80VXKturOacS6kaQmMCXS+ZyPytZT0K XJIgM3QrHsUUd6FnCHZ6Z6PBRLWl72RvNm8b2ZUE32puALlEeDCcd9PP3pyPITgj iU3gP05GafKzG/7liqQuWPffRqAq4oQyQYCjkRfBdPNlacACvbtAXNnDPnwkfIqg Si2Svj2TDS0eTxC5fspQtdWkKru50ZHTFFsoNhT33uX9L1Yr8ui+ajRG0Zxd81fj 0YGGat9QhzF6R2dywU75wXRveM/VMXj2wy5/CWBVI9kY84SeqcDDdkksG3iMC63Q ebkZF38kbZ85Xwpi3z2yHxw16yKg0pLNryW/GBp0xyJz5ivFhgpeFWEHfmjmiX+u Ka0E5RgCHh/eNAihbU8XN9MLnHToaX3mlEM+He+YsAXCMutaiSKaFpUhEs7uVmqu r8YIYLbxJcIfqrRyIJtn9RpWisxJfo/RVLyE3QDg7Pg5x6QeVysyuYkbeOdIk75e KW5B0b3eKh8Xu0mZqexdL9Hb1kEii5RxbSU5qLYoKfkMSo4/dLKgJwYZH61EC5cP dEj/KaIAdMA0VMi8XQfAsPIR4FKhKcd5tUazjBaW97WJjha0dog= =StiT -----END PGP SIGNATURE----- _______________________________________________ email@example.com mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-announce To unsubscribe, send any mail to "firstname.lastname@example.org"