Insufficient or missing error handling in certain routines dealing
with guest memory reads can lead to uninitialized data on the
hypervisor stack (potentially containing sensitive data from prior
work the hypervisor performed) being copied to guest visible storage.
This allows a malicious HVM guest to craft certain operations (namely,
but not limited to, port or memory mapped I/O writes) involving
physical or virtual addresses that have no actual memory associated
with them, so that hypervisor stack contents are copied into the
destination of the operation, thus becoming visible to the guest.
A malicious HVM guest could use this flaw to read data relating to other
Red Hat would like to thank the Xen project for reporting this issue.
This issue does affect the version of the kernel-xen package as shipped with Red Hat Enterprise Linux 5.
This issue does not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG as we did not have support for Xen hypervisor.
This is now public:
Created xen tracking bugs for this issue:
Affects: fedora-all [bug 1013748]
xen-4.3.0-7.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
xen-4.2.3-3.fc18 has been pushed to the Fedora 18 stable repository. If problems still persist, please make note of it in this bug report.
xen-4.2.3-3.fc19 has been pushed to the Fedora 19 stable repository. If problems still persist, please make note of it in this bug report.
This issue has been addressed in following products:
Red Hat Enterprise Linux 5
Via RHSA-2013:1790 https://rhn.redhat.com/errata/RHSA-2013-1790.html