Due converting PIO to the new memory read/write api we no longer provide separate I/O region lenghts for read and write operations. As a result, reading from PIT Mode/Command register will end with accessing pit->channels with invalid index and potentially cause memory corruption and/or minor information leak. A privileged guest user in a guest with QEMU PIT emulation enabled could potentially (tough unlikely) use this flaw to execute arbitrary code on the host with the privileges of the hosting QEMU process. (QEMU part of the vulnerability) A privileged guest user in a guest could potentially (tough unlikely) use this flaw to execute arbitrary code on the host. (KVM part of the vulnerability) Acknowledgements: Red Hat would like to thank Matt Tait of Google's Project Zero security team for reporting this issue.
Created attachment 1036692 [details] Upstream patch
Statement: This issue does not affect the versions of the qemu and qemu-kvm packages as shipped with Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3. This issue does affect the Red Hat Enterprise Linux 7 qemu-kvm and Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3. Future updates for the respective releases may address this flaw. Please note that by default QEMU/KVM guests use in-kernel (KVM) PIT emulation in which case the following applies: This issue does not affect the Linux kernel versions as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise Linux MRG 2. This issue does affect the kvm package as shipped with Red Hat Enterprise Linux 5. Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
Upstream patch submission: https://www.mail-archive.com/qemu-devel@nongnu.org/msg304063.html
Upstream commits: KVM -- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ee73f656a604d5aa9df86a97102e4e462dd79924 QEMU -- http://git.qemu.org/?p=qemu.git;a=commit;h=d4862a87e31a51de9eb260f25c9e99a75efe3235
Created qemu tracking bugs for this issue: Affects: fedora-all [bug 1243728]
Created qemu tracking bugs for this issue: Affects: epel-7 [bug 1243729]
This issue has been addressed in the following products: RHEV-H and Agents for RHEL-7 Via RHSA-2015:1508 https://rhn.redhat.com/errata/RHSA-2015-1508.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:1507 https://rhn.redhat.com/errata/RHSA-2015-1507.html
This issue has been addressed in the following products: OpenStack 5 for RHEL 7 OpenStack 6 for RHEL 7 Via RHSA-2015:1512 https://rhn.redhat.com/errata/RHSA-2015-1512.html
qemu-2.3.1-1.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
qemu-2.4.0-1.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
qemu-2.1.3-9.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.