Bug 1337806 (CVE-2016-4440) - CVE-2016-4440 Kernel: kvm: vmx: incorrect state update leading to MSR access
Summary: CVE-2016-4440 Kernel: kvm: vmx: incorrect state update leading to MSR access
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2016-4440
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1337807
Blocks: 1337277
TreeView+ depends on / blocked
 
Reported: 2016-05-20 06:37 UTC by Prasad Pandit
Modified: 2021-02-17 03:52 UTC (History)
28 users (show)

Fixed In Version:
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Last Closed: 2019-06-08 02:52:10 UTC
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Description Prasad Pandit 2016-05-20 06:37:59 UTC 
Linux kernel built with the Kernel-based virtual machine(CONFIG_KVM) along
with Hyper-v Synthetic Interrupt Controller(SynIC) support is vulnerable to
an undue APIC register access issue. In that a guest with SynIC enabled, could
gain access to host's Machine Specific Registers(MSR).

A privileged user inside guest could use this flaw to crash the host kernel
resulting in DoS OR potentially leverage it to escalate privileges on the host.

Upstream patch:
---------------
  -> http://permalink.gmane.org/gmane.comp.emulators.kvm.devel/152191

Reference:
----------
  -> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/152100


Note: It requires fairly latest features to be available and enabled on the
host(APICv) as well as in the guest(-hv-synic).
Comment 1 Prasad Pandit 2016-05-20 06:38:48 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1337807]
Comment 2 Prasad Pandit 2016-05-20 06:39:45 UTC 
Statement:

This issue does not affect the versions of the kernel package as shipped with
Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.
Comment 4 Fedora Update System 2016-06-02 14:58:20 UTC 
kernel-4.5.5-201.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
Comment 5 Fedora Update System 2016-06-18 18:50:00 UTC 
kernel-4.5.6-300.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.
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