1. Forum
  2. Usenet
  3. COMP.UNIX.BSD.FREEBSD.ANN

  • [FreeBSD-Announce] FreeBSD Security Advisory FreeBSD-SA-20:29.bhyve_svm

    From FreeBSD Security Advisories@21:1/5 to All on Tue Sep 15 23:53:01 2020
    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA512

    ============================================================================= FreeBSD-SA-20:29.bhyve_svm Security Advisory
    The FreeBSD Project

    Topic: bhyve SVM guest escape

    Category: core
    Module: bhyve
    Announced: 2020-09-15
    Credits: Maxime Villard
    Affects: All supported versions of FreeBSD.
    Corrected: 2020-09-15 20:25:30 UTC (stable/12, 12.2-STABLE)
    2020-09-15 21:46:39 UTC (releng/12.2, 12.2-BETA1-p1)
    2020-09-15 21:46:39 UTC (releng/12.1, 12.1-RELEASE-p10)
    2020-09-15 20:26:31 UTC (stable/11, 11.4-STABLE)
    2020-09-15 21:46:39 UTC (releng/11.4, 11.4-RELEASE-p4)
    2020-09-15 21:46:39 UTC (releng/11.3, 11.3-RELEASE-p14)
    CVE Name: CVE-2020-7467

    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/>.

    I. Background

    bhyve(8) is a hypervisor that supports running a variety of guest operating systems in virtual machines on AMD and Intel CPUs. AMD and Intel provide broadly similar virtualization interfaces, but each provides its own specific instructions for manipulating virtual machine state.

    II. Problem Description

    A number of AMD virtualization instructions operate on host physical
    addresses, are not subject to nested page table translation, and guest use of these instructions was not trapped.

    III. Impact

    - From kernel mode a malicious guest can write to arbitrary host memory (with some constraints), affording the guest full control of the host.

    IV. Workaround

    No workaround is available. Systems not using bhyve, and systems that
    use bhyve with an Intel CPU, are not vulnerable.

    V. Solution

    Upgrade your vulnerable system to a supported FreeBSD stable or
    release / security branch (releng) dated after the correction date,
    and reboot.

    Perform one of the following:

    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
    # shutdown -r +10min "Rebooting for a security update"

    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.

    # fetch https://security.FreeBSD.org/patches/SA-20:29/bhyve_svm.patch
    # fetch https://security.FreeBSD.org/patches/SA-20:29/bhyve_svm.patch.asc
    # gpg --verify bhyve_svm.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> and reboot the
    system.

    VI. Correction details

    The following list contains the correction revision numbers for each
    affected branch.

    Branch/path Revision
    - ------------------------------------------------------------------------- stable/12/ r365767 releng/12.2/ r365780 releng/12.1/ r365780 stable/11/ r365769 releng/11.4/ r365780 releng/11.3/ r365780
    - -------------------------------------------------------------------------

    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://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-7467>

    The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-20:29.bhyve_svm.asc> -----BEGIN PGP SIGNATURE-----

    iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAl9hOJhfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cJxjxAAjy783UUnVvhtiJt4p5TGMpaU+ZrLnKaOASiTDdbp6z3IFuLZ1VbkekAM aMGgZNmYkRotcTM0mbhoeRROSrYlmO2ZHNmJyxchbOaIfKXL3iTFYP5gRirN1r+Q i8+Gr5HzTL5SkvTEx0wKUp6uRqD26nf7i4KrdOWmf5ivhB66Z2vk/56aX53eSNJ5 iPZYvlFnVIcy1wKPE1RIP67H+nqqWBApavWUMK6f01cAMr5w0BE+f4RdSvzEFnuG p2Id8A3ptt0VoIdZzbJkLKog4/dlC1C+PVPPLND2gcCY2c/+gG0nNTy9Fjdvsoor AnmRvlarCCcEVOSxGk+WNUwWdQnQPFykpZxGtid53km3Yjw1smPmfOVwvNhTkzoP tPZ568wFyaBGLI+39hC0u0AtLT93MBHpxpCMpQZ9rlFauxn5OuyBFkxgCuEyq728 GcrMVggyrzOetW7GqdlOEzFDj3nxHme+08qmbLXjv5X8N1RK+TGZDAjYFqLU1NXi cyPhbGqV4SuYw3dW7E0C8eOocuVmpXTEW82R9ff1pobUZUNVGKZse1rjT344VTSc DazL/q2TIo5fyDWEaNWsPad8mdyQGWft2cfYHYrO+Y6Smn/oKS3LmX61bGC37FEF b0rqunbDdq4775q6H6KKbRgVTKGiVyC/Nt/2xkg//GymzNnuFvY=
    =lplz
    -----END PGP SIGNATURE-----
    _______________________________________________
    freebsd-announce@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-announce
    To unsubscribe, send any mail to "freebsd-announce-unsubscribe@freebsd.org"

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)