metadata/glsa/glsa-201703-07.xml


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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
<glsa id="201703-07">
  <title>Xen: Privilege Escalation</title>
  <synopsis>A vulnerability in Xen's bundled QEMU version might allow privilege
    escalation.
  </synopsis>
  <product type="ebuild">xen</product>
  <announced>2017-03-28</announced>
  <revised count="1">2017-03-28</revised>
  <bug>609120</bug>
  <access>local</access>
  <affected>
    <package name="app-emulation/xen-tools" auto="yes" arch="*">
      <unaffected range="ge">4.7.1-r8</unaffected>
      <vulnerable range="lt">4.7.1-r8</vulnerable>
    </package>
  </affected>
  <background>
    <p>Xen is a bare-metal hypervisor.</p>
  </background>
  <description>
    <p>In CIRRUS_BLTMODE_MEMSYSSRC mode the bitblit copy routine
      cirrus_bitblt_cputovideo fails to check wethehr the specified memory
      region is safe.
    </p>
  </description>
  <impact type="normal">
    <p>A local attacker could potentially execute arbitrary code with
      privileges of Xen (QEMU) process on the host, gain privileges on the host
      system, or cause a Denial of Service condition.
    </p>
  </impact>
  <workaround>
    <p>Running guests in Paravirtualization (PV)  mode,  or running guests in
      Hardware-assisted virtualizion (HVM) utilizing stub domains mitigate
      the issue.
    </p>
    
    <p>Running HVM guests with the device model in a stubdomain will mitigate
      the issue.
    </p>
    
    <p>Changing the video card emulation to stdvga (stdvga=1, vga=”stdvga”,
      in the xl domain configuration) will avoid the vulnerability.
    </p>
  </workaround>
  <resolution>
    <p>All Xen Tools users should upgrade to the latest version:</p>
    
    <code>
      # emerge --sync
      # emerge --ask --oneshot --verbose
      "&gt;=app-emulation/xen-tools-4.7.1-r8"
    </code>
    
  </resolution>
  <references>
    <uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2017-2620">CVE-2017-2620</uri>
  </references>
  <metadata tag="requester" timestamp="2017-02-24T02:24:45Z">BlueKnight</metadata>
  <metadata tag="submitter" timestamp="2017-03-28T03:15:18Z">whissi</metadata>
</glsa>