File _patchinfo of Package patchinfo.7444

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File _patchinfo of Package patchinfo.7444

<patchinfo incident="7444">
  <issue id="1092885" tracker="bnc">VUL-0: EMBARGOED: CVE-2018-3639:  qemu,kvm,libvirt: V4 &#8211; Speculative Store Bypass aka "Memory Disambiguation"</issue>
  <issue id="1082276" tracker="bnc">KVM doesn't correctly return CPUID_7_0_EDX_SPEC_CTRL as supported feature</issue>
  <issue id="1068032" tracker="bnc">VUL-0: speculative side channel attacks on various CPU platforms aka "SpectreAttack" and "MeltdownAttack"</issue>
  <issue id="2017-5715" tracker="cve" />
  <issue id="2018-3639" tracker="cve" />
  <category>security</category>
  <rating>important</rating>
  <packager>bfrogers</packager>
    <description>This update for qemu fixes several issues.

This security issue was fixed:

- CVE-2018-3639: Spectre v4 vulnerability mitigation support for KVM guests (bsc#1092885).

Systems with microprocessors utilizing speculative execution and speculative
  execution of memory reads before the addresses of all prior memory writes are
  known may allow unauthorized disclosure of information to an attacker with
  local user access via a side-channel analysis.

This patch permits the new x86 cpu feature flag named "ssbd" to be
  presented to the guest, given that the host has this feature, and
  KVM exposes it to the guest as well.

For this feature to be enabled please use the qemu commandline
  -cpu $MODEL,+spec-ctrl,+ssbd
  so the guest OS can take advantage of the feature.

spec-ctrl and ssbd support is also required in the host.
- CVE-2017-5715: 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. We remove that
  initial patch and now rely on patches from upstream (bsc#1068032).

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 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)
</description>
  <summary>Security update for qemu</summary>
</patchinfo>

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