Security update for kvm

SUSE Security Update: Security update for kvm
Announcement ID: SUSE-SU-2018:1308-1
Rating: important
References: #1068032 #1076114 #1076179 #1082276 #1083291
Affected Products:
  • SUSE Linux Enterprise Server 11-SP3-LTSS
  • SUSE Linux Enterprise Point of Sale 11-SP3

  • An update that solves four vulnerabilities and has one errata is now available.


    This update for kvm fixes the following issues:

    This update has the next round of Spectre v2 related patches, which now
    integrates with corresponding changes in libvirt. A January 2018 release
    of qemu initially addressed the Spectre v2 vulnerability for KVM guests by
    exposing the spec-ctrl feature for all x86 vcpu types, which was the quick
    and dirty approach, but not the proper solution. We remove that initial
    patch and now rely on patches from upstream. This update defines spec_ctrl
    and ibpb cpu feature flags as well as new cpu models which are clones
    of existing models with either -IBRS or -IBPB added to the end of the
    model name. These new vcpu models explicitly include the new feature(s),
    whereas the feature flags can be added to the cpu parameter as with other
    features. In short, for continued Spectre v2 protection, ensure that
    either the appropriate cpu feature flag is added to the QEMU
    command-line, or one of the new cpu models is used. Although migration
    from older versions is supported, the new cpu features won't be properly
    exposed to the guest until it is restarted with the cpu features
    explicitly added. A reboot is insufficient.

    A warning patch is added which attempts to detect a migration from a qemu
    version which had the quick and dirty fix (it only detects certain cases,
    but hopefully is helpful.)

    For additional information on Spectre v2 as it relates to QEMU, see:

    (CVE-2017-5715 bsc#1068032)

    A patch is added to continue to detect Spectre v2 mitigation features (as
    shown by cpuid), and if found provide that feature to guests, even if
    running on older KVM (kernel) versions which do not yet expose that
    feature to QEMU. (bsc#1082276)

    Additional security fixes:

    - CVE-2018-5683: An out-of-bounds read in vga_draw_text routine was fixed
    which could lead to crashes or information leakage. (bsc#1076114)
    - CVE-2018-7550: multiboot OOB access while loading kernel image was fixed
    that could lead to crashes (bsc#1083291)
    - CVE-2017-18030: An out-of-bounds access in cirrus_invalidate_region
    routine could lead to crashes or information leakage (bsc#1076179)

    - Eliminate bogus use of CPUID_7_0_EDX_PRED_CMD which we've carried since
    the initial Spectre v2 patch was added. EDX bit 27 of CPUID Leaf 07H,
    Sub-leaf 0 provides status on STIBP, and not the PRED_CMD MSR. Exposing
    the STIBP CPUID feature bit to the guest is wrong in general, since the
    VM doesn't directly control the scheduling of physical hyperthreads.
    This is left strictly to the L0 hypervisor.

    Patch Instructions:

    To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
    Alternatively you can run the command listed for your product:

    • SUSE Linux Enterprise Server 11-SP3-LTSS:
      zypper in -t patch slessp3-kvm-13603=1
    • SUSE Linux Enterprise Point of Sale 11-SP3:
      zypper in -t patch sleposp3-kvm-13603=1

    Package List:

    • SUSE Linux Enterprise Server 11-SP3-LTSS (i586 s390x x86_64):
      • kvm-1.4.2-53.17.1
    • SUSE Linux Enterprise Point of Sale 11-SP3 (i586):
      • kvm-1.4.2-53.17.1