|Public release ||2014-11-20 16:26|
|Updated ||2014-11-21 12:25|
|Title ||Guest effectable page reference leak in MMU_MACHPHYS_UPDATE handling|
Filesadvisory-113.txt (signed advisory file)
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Xen Security Advisory CVE-2014-9030 / XSA-113
Guest effectable page reference leak in MMU_MACHPHYS_UPDATE handling
UPDATES IN VERSION 2
An error handling path in the processing of MMU_MACHPHYS_UPDATE failed
to drop a page reference which was acquired in an earlier processing
Malicious or buggy stub domain kernels or tool stacks otherwise living
outside of Domain0 can mount a denial of service attack which, if
successful, can affect the whole system.
Only domains controlling HVM guests can exploit this vulnerability.
(This includes domains providing hardware emulation services to HVM
Xen versions from at least 3.2.x onwards are vulnerable on x86 systems.
Older versions have not been inspected. ARM systems are not vulnerable.
This vulnerability is only applicable to Xen systems using stub domains
or other forms of disaggregation of control domains for HVM guests.
Running only PV guests will avoid this issue.
(The security of a Xen system using stub domains is still better than
with a qemu-dm running as an unrestricted dom0 process. Therefore
users with these configurations should not switch to an unrestricted
NOTE REGARDING LACK OF EMBARGO
A draft of this advisory was mistakenly sent to xen-devel. The Xen
Project Security Team apologises for this error. We are working to
share best working practices amongst the team to reduce the risks of
This issue was discovered by Andrew Cooper of Citrix.
Applying the attached patch resolves this issue.
xsa113.patch xen-unstable, Xen 4.4.x, Xen 4.3.x, Xen 4.2.x
$ sha256sum xsa113*.patch
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Xenproject.org Security Team