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Red Hat: 2011:1531-03: qemu-kvm: Moderate Advisory Print E-mail
User Rating:      How can I rate this item?
Posted by Benjamin D. Thomas   
RedHat Linux Updated qemu-kvm packages that fix one security issue, multiple bugs, and add various enhancements are now available for Red Hat Enterprise Linux 6. The Red Hat Security Response Team has rated this update as having moderate [More...]
                   Red Hat Security Advisory

Synopsis:          Moderate: qemu-kvm security, bug fix, and enhancement update
Advisory ID:       RHSA-2011:1531-03
Product:           Red Hat Enterprise Linux
Advisory URL:
Issue date:        2011-12-06
CVE Names:         CVE-2011-2527 

1. Summary:

Updated qemu-kvm packages that fix one security issue, multiple bugs, and
add various enhancements are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team 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 from the CVE link in
the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - x86_64
Red Hat Enterprise Linux HPC Node (v. 6) - x86_64
Red Hat Enterprise Linux Server (v. 6) - x86_64
Red Hat Enterprise Linux Workstation (v. 6) - x86_64

3. Description:

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. qemu-kvm is the user-space component
for running virtual machines using KVM.

It was found that qemu-kvm did not properly drop supplemental group
privileges when the root user started guests from the command line
("/usr/libexec/qemu-kvm") with the "-runas" option. A qemu-kvm process
started this way could use this flaw to gain access to files on the host
that are accessible to the supplementary groups and not accessible to the
primary group. (CVE-2011-2527)

Note: This issue only affected qemu-kvm when it was started directly from
the command line. It did not affect the Red Hat Enterprise Virtualization
platform or applications that start qemu-kvm via libvirt, such as the
Virtual Machine Manager (virt-manager).

This update also fixes several bugs and adds various enhancements.
Documentation for these bug fixes and enhancements will be available
shortly from the Technical Notes document, linked to in the References

All users of qemu-kvm are advised to upgrade to these updated packages,
which contain backported patches to correct these issues and add these
enhancements. After installing this update, shut down all running virtual
machines. Once all virtual machines have shut down, start them again for
this update to take effect.

4. Solution:

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at

5. Bugs fixed (

561414 - Writes to virtual usb-storage produce I/O errors
599306 - Some strange behaviors on key's appearance viewed by using vnc
609342 - rhel3u9 install can't find package after inserting second CD, but install can continue
621482 - [RFE] Be able to get progress from qemu-img
624983 - QEMU should support the newer set of MSRs for kvmclock
627585 - Improve error messages for bad options in -drive and -device
633370 - [6.1 FEAT] Enhance QED image format to support streaming from remote systems
633380 - [6.2 FEAT] Include QED image format for KVM guests
645351 - Add support for USB 2.0 (EHCI) to QEMU
655719 - no error pops when change cd to non-exist file
656779 - Core dumped when hot plug/un-plug virtio serial port to the same chardev
658467 - kvm clock breaks migration result stability -  for unit test propose
669581 - Migration Never end while Use firewall reject migration tcp port
676982 - RFE: no qmp command for live snapshot
678729 - Hotplug VF/PF with invalid addr value leading to qemu-kvm process quit with core dump
678731 - Update qemu-kvm -device pci-assign,?  properties
680378 - no error message when loading zero size internal snapshot
681736 - Guest->Host communication stops for other ports after one port is unplugged
682227 - qemu-kvm doesn't exit when binding to specified port fails
693645 - RFE: add spice option to enable/disable copy paste
694373 - ballooning value reset to original value after setting a negative number
694378 - Core dump occurs when ballooning memory to 0
698537 - ide: core dump when stop/cont guest
700134 - [qemu-kvm] - qxl runs i/o requests synchronously
705070 - QMP: screendump command does not allow specification of monitor to capture
707130 - ACPI description of serial and parallel ports incorrect with -chardev/-device
709397 - virtio-serial unthrottling needs to use a bottomhalf to avoid recursion
710046 - qemu-kvm prints warning "Using CPU model [...]" (with patch)
711354 - Fix and enable enough of SCSI to make usb-storage work
712046 - Qemu allocates an existed macaddress to hotpluged nic
714773 - qemu missing marker for qemu.kvm.qemu_vmalloc
715017 - Report disk latency (read and write) for each storage device
715141 - Wrong Ethertype for RARP
715582 - qemu-kvm doesn't report error when supplied negative spice port value
717958 - qemu-kvm start vnc even though -spice ... is supplied
718664 - Migration from host RHEL6.1+ to host RHEL6.0.z failed with floppy
720237 - usb migration compatibility
720773 - CVE-2011-2527 qemu: when started as root, extra groups are not dropped correctly
720979 - do not use next  as a variable name in qemu-kvm systemtap tapset
722728 - Update qemu-img convert/re-base man page
723270 - Report cdrom tray status in a monitor command such as info block
723858 - usb: add companion controller support
723863 - usb: fixes various issues.
723864 - usb: compile out the crap
723870 - tag devices without migration support
725565 - migration subsections are still broken
725625 - Hot unplug one virtio balloon device cause another balloon device unavailable
725965 - spice client mouse doesn't work after migration
726014 - Fix memleak on exit in virtio-balloon
726015 - Fix memleak on exit in virtio-blk
726020 - Fix memleaks in all virtio devices
726023 - Migration after hot-unplug virtio-balloon will not succeed
728120 - print error on usb speed mismatch between device and bus/port
728464 - QEMU does not honour '-no-shutdown' flag after the first shutdown attempt
729104 - qemu-kvm: pci needs multifunction property
729572 - qcow2: Loading internal snapshot can corrupt image
729621 - ASSERT worker->running failed on source qemu during migration with Spice session
729869 - qxl: primary surface not saved on migration
729969 - Make screendump command available in QMP
731759 - SPICE: migration fails with  warning: error while loading state section id 4
732949 - Guest screen becomes abnormal after migration with spice
733010 - core dump when issue fdisk -l in guest which has two usb-storage attached
733993 - migration target can crash (assert(d->ssd.running))
734860 - qemu-kvm: segfault when missing host parameter for socket chardev
734995 - Core dump when hotplug three usb-hub into the same port under both uhci and ehci
735716 - QEMU should report the PID of the process that sent it signals for troubleshooting purposes
736975 - Qemu-kvm fails to unregister virtio-balloon-pci device when unplugging
737921 - Spice password on migration target expires before Spice client is connected
738487 - Fix termination by signal with -no-shutdown
738555 - Stop exposing -enable-nested
739480 - qemu-kvm core dumps when migration with reboot
740547 - qxl: migrating in vga mode causes a "panic: virtual address out of range"
741878 - USB tablet mouse does not work well when migrating between 6.2<->6.2 hosts and 6.1<->6.2 hosts
742401 - qemu-kvm disable live snapshot support
742458 - Tracker Bug:Big block layer backport
742469 - Drives can not be locked without media present
742476 - Make eject fail for non-removable drives even with -f
742480 - Don't let locked flag prevent medium load
742484 - should be also have  snapshot on floppy
743269 - Hot unplug of snapshot device crashes
743342 - IDE CD-ROM tray state gets lost on migration
743391 - KVM guest limited to 40bit of physical address space
744518 - qemu-kvm core dumps when qxl-linux guest migrate with reboot
744780 - use-after-free in QEMU SCSI target code

6. Package List:

Red Hat Enterprise Linux Desktop (v. 6):



Red Hat Enterprise Linux HPC Node (v. 6):



Red Hat Enterprise Linux Server (v. 6):



Red Hat Enterprise Linux Workstation (v. 6):



These packages are GPG signed by Red Hat for security.  Our key and 
details on how to verify the signature are available from

7. References:

8. Contact:

The Red Hat security contact is .  More contact
details at

Copyright 2011 Red Hat, Inc.
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