Hide Forgot
If the guest writes a noncanonical value to certain MSR registers, KVM will write that value to the MSR in the host context and a #GP will be raised leading to kernel panic. A privileged guest user can use this flaw to crash the host. Enabling CONFIG_PARAVIRT when building the kernel mitigates this issue because wrmsrl() ends up invoking safe msr write variant. Acknowledgements: Red Hat would like to thank Lars Bull of Google and Nadav Amit for reporting this issue.
Statement: This issue does not affect Linux kernel packages as shipped with Red Hat Enterprise Linux 6 and 7. Future kvm package updates for Red Hat Enterprise Linux 5 may address this issue.
Upstream patches: http://git.kernel.org/cgit/virt/kvm/kvm.git/commit/?id=854e8bb1aa06c578c2c9145fa6bfe3680ef63b23 http://git.kernel.org/cgit/virt/kvm/kvm.git/commit/?id=8b3c3104c3f4f706e99365c3e0d2aa61b95f969f
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1156543]
kernel-3.16.6-203.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
kernel-3.17.2-300.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
kernel-3.14.23-100.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 the following products: Red Hat Enterprise Linux 5 Via RHSA-2015:0869 https://rhn.redhat.com/errata/RHSA-2015-0869.html