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Xen Security Advisory 10 - HVM guest user mode MMIO emulation DoS
From: Xen.org security team <security () xen org>
Date: Thu, 26 Jul 2012 16:30:43 +0100
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Xen Security Advisory XSA-10
HVM guest user mode MMIO emulation DoS vulnerability
Internal data of the emulator for MMIO operations may, under
certain rare conditions, at the end of one emulation cycle be left
in a state affecting a subsequent emulation such that this second
emulation would fail, causing an exception to be reported to the
guest kernel where none is expected.
Guest mode unprivileged (user) code, which has been granted
the privilege to access MMIO regions, may leverage that access
to crash the whole guest.
All HVM guests exposing MMIO ranges to unprivileged (user) mode.
All versions of Xen which support HVM guests are vulnerable to this issue.
This issue can be mitigated by running PV (para-virtualised)
guests only, or by ensuring (inside the guest) that MMIO regions
can be accessed only by trustworthy processes.
Applying the appropriate attached patch will resolve the issue.
NOTE REGARDING CVE
We do not yet have a CVE Candidate number for this vulnerability.
The attached patches resolve this issue
$ sha256sum xsa10-*.patch
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- Xen Security Advisory 10 - HVM guest user mode MMIO emulation DoS Xen . org security team (Jul 26)