xen-kernel -- PV superpage functionality missing sanity checks

The Xen Project reports: The PV superpage functionality lacks certain validity checks on data being passed to the hypervisor by guests. This is the case for the page identifier MFN passed to MMUEXTMARKSUPER and MMUEXTUNMARKSUPER sub-ops of the HYPERVISORmmuextop hypercall as well as for various...

xen-kernel -- information leak in legacy x86 FPU/XMM initialization

The Xen Project reports: When XSAVE/XRSTOR are not in use by Xen to manage guest extended register state, the initial values in the FPU stack and XMM registers seen by the guest upon first use are those left there by the previous user of those registers. A malicious domain may be able to leverage...

xen-tools -- libxl leak of pv kernel and initrd on error

The Xen Project reports: When constructing a guest which is configured to use a PV bootloader which runs as a userspace process in the toolstack domain e.g. pygrub libxl creates a mapping of the files to be used as kernel and initial ramdisk when building the guest domain. However if building the...

xen-kernel -- XENMEM_exchange error handling issues

The Xen Project reports: Error handling in the operation may involve handing back pages to the domain. This operation may fail when in parallel the domain gets torn down. So far this failure unconditionally resulted in the host being brought down due to an internal error being assumed. This is...

xen-kernel -- CPU lockup during exception delivery

The Xen Project reports: A malicious HVM guest administrator can cause a denial of service. Specifically, prevent use of a physical CPU for a significant, perhaps indefinite period. If a host watchdog Xen or dom0 is in use, this can lead to a watchdog timeout and consequently a reboot of the host...

xen-kernel -- some pmu and profiling hypercalls log without rate limiting

The Xen Project reports: HYPERCALLxenoprofop and HYPERVISORxenpmuop log some errors and attempts at invalid operations. These log messages are not rate-limited, even though they can be triggered by guests. A malicious guest could cause repeated logging to the hypervisor console, leading to a Deni...

xen-tools -- populate-on-demand balloon size inaccuracy can crash guests

The Xen Project reports: Guests configured with PoD might be unstable, especially under load. In an affected guest, an unprivileged guest user might be able to cause a guest crash, perhaps simply by applying load so as to cause heavy memory pressure within the guest...

xen-kernel -- Long latency populate-on-demand operation is not preemptible

The Xen Project reports: When running an HVM domain in Populate-on-Demand mode, Xen would sometimes search the domain for memory to reclaim, in response to demands for population of other pages in the same domain. This search runs without preemption. The guest can, by suitable arrangement of its...

Moderate: Red Hat Security Advisory: qemu-kvm security update

Updated qemu-kvm packages that fix one security issue are now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available fr...

xen-tools -- libxl fails to honour readonly flag on disks with qemu-xen

The Xen Project reports: Callers of libxl can specify that a disk should be read-only to the guest. However, there is no code in libxl to pass this information to qemu-xen the upstream-based qemu; and indeed there is no way in qemu to make a disk read-only. The vulnerability is exploitable only v...

RHEL 7 : qemu-kvm (RHSA-2015:1793)

Updated qemu-kvm packages that fix one security issue are now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available fr...

Moderate: Red Hat Security Advisory: qemu-kvm security fix update

Updated qemu-kvm packages that fix one security issue are now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available fr...

Moderate: Red Hat Security Advisory: qemu-kvm-rhev security update

Updated qemu-kvm-rhev packages that fix one security issue are now available for Red Hat Enterprise Virtualization Hypervisor 7. Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severit...

Moderate: Red Hat Security Advisory: qemu-kvm-rhev security update

Updated qemu-kvm-rhev packages that fix two security issues are now available for Red Hat Enterprise Linux OpenStack Platform 6. Red Hat Product Security has rated this update as having Moderate security impact. Common Vulnerability Scoring System CVSS base scores, which give detailed severity...

FreeBSD : qemu, xen-tools -- QEMU heap overflow flaw with certain ATAPI commands (da451130-365d-11e5-a4a5-002590263bf5)

The Xen Project reports : A heap overflow flaw was found in the way QEMU's IDE subsystem handled I/O buffer access while processing certain ATAPI commands. A privileged guest user in a guest with CDROM drive enabled could potentially use this flaw to execute arbitrary code on the host with the...

qemu, xen-tools -- QEMU heap overflow flaw with certain ATAPI commands

The Xen Project reports: A heap overflow flaw was found in the way QEMU's IDE subsystem handled I/O buffer access while processing certain ATAPI commands. A privileged guest user in a guest with CDROM drive enabled could potentially use this flaw to execute arbitrary code on the host with the...

FreeBSD : xen-kernel -- Certain domctl operations may be abused to lock up the host (103a47d5-27e7-11e5-a4a5-002590263bf5)

The Xen Project reports : XSA-77 put the majority of the domctl operations on a list excepting them from having security advisories issued for them if any effects their use might have could hamper security. Subsequently some of them got declared disaggregation safe, but for a small subset this wa...

FreeBSD : xen-tools -- Unmediated PCI register access in qemu (3d657340-27ea-11e5-a4a5-002590263bf5)

The Xen Project reports : Qemu allows guests to not only read, but also write all parts of the PCI config space but not extended config space of passed through PCI devices not explicitly dealt with for partial emulation purposes. Since the effect depends on the specific purpose of the the config...

FreeBSD : xen-tools -- Guest triggerable qemu MSI-X pass-through error messages (cbe1a0f9-27e9-11e5-a4a5-002590263bf5)

The Xen Project reports : Device model code dealing with guest PCI MSI-X interrupt management activities logs messages on certain supposedly invalid guest operations. A buggy or malicious guest repeatedly invoking such operations may result in the host disk to fill up, possibly leading to a Denia...

FreeBSD : xen-kernel and xen-tools -- Long latency MMIO mapping operations are not preemptible (d40c66cb-27e4-11e5-a4a5-002590263bf5)

The Xen Project reports : The XENDOMCTLmemorymapping hypercall allows long running operations without implementing preemption. This hypercall is used by the device model as part of the emulation associated with configuration of PCI devices passed through to HVM guests and is therefore indirectly...