Topic

Updated qemu-kvm packages that fix multiple security issues, several bugs,
and add various enhancements are now available for Red Hat Enterprise
Linux 7.

Red Hat Product Security has rated this update as having Important security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

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

It was found that the Cirrus blit region checks were insufficient. A privileged
guest user could use this flaw to write outside of VRAM-allocated buffer
boundaries in the host's QEMU process address space with attacker-provided data.
(CVE-2014-8106)

An uninitialized data structure use flaw was found in the way the
set_pixel_format() function sanitized the value of bits_per_pixel. An attacker
able to access a guest's VNC console could use this flaw to crash the guest.
(CVE-2014-7815)

It was found that certain values that were read when loading RAM during
migration were not validated. A user able to alter the savevm data (either on
the disk or over the wire during migration) could use either of these flaws to
corrupt QEMU process memory on the (destination) host, which could potentially
result in arbitrary code execution on the host with the privileges of the QEMU
process. (CVE-2014-7840)

A NULL pointer dereference flaw was found in the way QEMU handled UDP packets
with a source port and address of 0 when QEMU's user networking was in use. A
local guest user could use this flaw to crash the guest. (CVE-2014-3640)

Red Hat would like to thank James Spadaro of Cisco for reporting CVE-2014-7815,
and Xavier Mehrenberger and Stephane Duverger of Airbus for reporting
CVE-2014-3640. The CVE-2014-8106 issue was found by Paolo Bonzini of Red Hat,
and the CVE-2014-7840 issue was discovered by Michael S. Tsirkin of Red Hat.

Bug fixes:

• The KVM utility executed demanding routing update system calls every time it

performed an MSI vector mask/unmask operation. Consequently, guests running
legacy systems such as Red Hat Enterprise Linux 5 could, under certain
circumstances, experience significant slowdown. Now, the routing system calls
during mask/unmask operations are skipped, and the performance of legacy guests
is now more consistent. (BZ#1098976)

• Due to a bug in the Internet Small Computer System Interface (iSCSI) driver, a

qemu-kvm process terminated unexpectedly with a segmentation fault when the
"write same" command was executed in guest mode under the iSCSI protocol. This
update fixes the bug, and the "write same" command now functions in guest mode
under iSCSI as intended. (BZ#1083413)

• The QEMU command interface did not properly handle resizing of cache memory

during guest migration, causing QEMU to terminate unexpectedly with a
segmentation fault. This update fixes the related code, and QEMU no longer
crashes in the described situation. (BZ#1066338)

Enhancements:

• The maximum number of supported virtual CPUs (vCPUs) in a KVM guest has been

increased to 240. This increases the number of virtual processing units that the
user can assign to the guest, and therefore improves its performance potential.
(BZ#1134408)

• Support for the 5th Generation Intel Core processors has been added to the

QEMU hypervisor, the KVM kernel code, and the libvirt API. This allows KVM
guests to use the following instructions and features: ADCX, ADOX, RDSFEED,
PREFETCHW, and supervisor mode access prevention (SMAP). (BZ#1116117)

• The "dump-guest-memory" command now supports crash dump compression. This

makes it possible for users who cannot use the "virsh dump" command to require
less hard disk space for guest crash dumps. In addition, saving a compressed
guest crash dump frequently takes less time than saving a non-compressed one.
(BZ#1157798)

• This update introduces support for flight recorder tracing, which uses

SystemTap to automatically capture qemu-kvm data while the guest machine is
running. For detailed instructions on how to configure and use flight recorder
tracing, see the Virtualization Deployment and Administration Guide, linked to
in the References section below. (BZ#1088112)

Solution

All qemu-kvm users 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.

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for Power, big endian 7 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.7 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.7 ppc64
• Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 895436 - qemu-kvm core dump when guest do S3/S4 with max(232) virtio block devices (multifunction=on)
• BZ - 949385 - passthrough USB speaker to win2012 guest fail to work well
• BZ - 980747 - flood with 'xhci: wrote doorbell while xHC stopped or paused' when redirected USB Webcam from usb-host with xHCI controller
• BZ - 980833 - xhci: FIXME: endpoint stopped w/ xfers running, data might be lost
• BZ - 990724 - qemu-kvm failing when invalid machine type is provided
• BZ - 996011 - vlan and queues options cause core dumped when qemu-kvm process quit(or ctrl+c)
• BZ - 999789 - qemu should give a more friendly prompt when didn't specify read-only for VMDK format disk
• BZ - 1002493 - qemu-img convert rate about 100k/second from qcow2/raw to vmdk format on nfs system file
• BZ - 1017685 - Gluster etc. should not be a dependency of vscclient and libcacard
• BZ - 1021788 - the error message "scsi generic interface too old" is wrong more often than not
• BZ - 1026314 - BUG: qemu-kvm hang when use '-sandbox on'+'vnc'+'hda'
• BZ - 1027565 - fail to reboot guest after migration from RHEL6.5 host to RHEL7.0 host
• BZ - 1029271 - Format specific information (create type) was wrong when create it specified subformat='streamOptimized'
• BZ - 1038914 - Guest can't receive any character transmitted from host after hot unplugging virtserialport then hot plugging again
• BZ - 1039791 - qemu-img creates truncated VMDK image with subformat=twoGbMaxExtentFlat
• BZ - 1046574 - fail to passthrough the USB speaker redirected from usb-redir with xhci controller
• BZ - 1046873 - fail to be recognized the hotpluging usb-storage device with xhci controller in win2012R2 guest
• BZ - 1049734 - PCI: QEMU crash on illegal operation: attaching a function to a non multi-function device
• BZ - 1052093 - qcow2 corruptions (leaked clusters after installing a rhel7 guest using virtio_scsi)
• BZ - 1054077 - qemu crash when reboot win7 guest with spice display
• BZ - 1064156 - [qxl] The guest show black screen while resumed guest which managedsaved in pmsuspended status.
• BZ - 1064647 - qemu-kvm core dump when hot-plug virtio-blk-pci device with gluster backend
• BZ - 1066338 - Reduce the migrate cache size during migration causes qemu segment fault
• BZ - 1074219 - qemu core dump when install a RHEL.7 guest(xhci) with migration
• BZ - 1074403 - qemu-kvm can not give any warning hint when set sndbuf with negative value
• BZ - 1074913 - migration can not finish with 1024k 'remaining ram' left after hotunplug 4 nics
• BZ - 1075846 - qemu-kvm core dumped when hotplug/unhotplug USB3.0 device multi times
• BZ - 1076326 - qemu-kvm does not quit when booting guest w/ 161 vcpus and "-no-kvm"
• BZ - 1079147 - [WHQL][balloon][virtio-rng]ob named DPWLK-HotADD-Device Test- Verify dirver support for Hot-Add CPU made win2k8-R2 BSOD (0x7E)
• BZ - 1083413 - qemu-kvm: iSCSI: Failure. SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:INVALID_FIELD_IN_CDB(0x2400)
• BZ - 1085701 - Guest hits call trace migrate from RHEL6.5 to RHEL7.0 host with -M 6.1 & balloon & uhci device
• BZ - 1086598 - migrate_cancel wont take effect on previouly wrong migrate -d cmd
• BZ - 1086987 - src qemu crashed when starting migration in inmigrate mode
• BZ - 1088116 - qemu crash when device_del usb-redir
• BZ - 1088150 - qemu-img coredumpd when try to create a gluster format image
• BZ - 1088176 - QEMU fail to check whether duplicate ID for block device drive using 'blockdev-add' to hotplug
• BZ - 1088695 - there are four "gluster" in qemu-img supported format list
• BZ - 1088822 - hot-plug a virtio-scsi disk via 'blockdev-add' always cause QEMU quit
• BZ - 1089606 - QEMU will not reject invalid number of queues (num_queues = 0) specified for virtio-scsi
• BZ - 1093983 - there are three "nbd" in qemu-img supported format list
• BZ - 1094285 - Hot plug CPU not working with RHEL6 machine types running on RHEL7 host.
• BZ - 1095645 - vectors of virtio-scsi-pci will be 0 when set vectors>=129
• BZ - 1096576 - QEMU core dumped when boot up two scsi-hd disk on the same virtio-scsi-pci controller in Intel host
• BZ - 1097020 - [RFE] qemu-img: Add/improve Disk2VHD tools creating VHDX images
• BZ - 1097363 - qemu ' KVM internal error. Suberror: 1' when query cpu frequently during pxe boot in Intel "Q95xx" host
• BZ - 1098086 - RFE: Supporting creating vmdk/vdi/vpc format disk with protocols (glusterfs)
• BZ - 1104748 - 48% reduction in IO performance for KVM guest, io=native
• BZ - 1107821 - rdma migration: seg if destination isn't listening
• BZ - 1111450 - Guest crash when hotplug usb while disable virt_use_usb
• BZ - 1113009 - Migration failed with virtio-blk from RHEL6.5.0 host to RHEL7.0 host
• BZ - 1116728 - Backport qemu_bh_schedule() race condition fix
• BZ - 1116941 - Return value of virtio_load not checked in virtio_rng_load
• BZ - 1118707 - VMstate static checker: backport -dump-vmstate feature to export json-encoded vmstate info
• BZ - 1122151 - Pass close from qemu-ga
• BZ - 1123372 - qemu-kvm crashed when doing iofuzz testing
• BZ - 1130428 - After migration of RHEL7.1 guest with "-vga qxl", GUI console is hang
• BZ - 1131316 - fail to specify wwn for virtual IDE CD-ROM
• BZ - 1134237 - Opening malformed VMDK description file should fail
• BZ - 1134241 - QEMU fails to correctly read/write on VMDK with big flat extent
• BZ - 1134251 - Opening an obviously truncated VMDK image should fail
• BZ - 1134283 - qemu-img convert from ISO to streamOptimized fails
• BZ - 1138639 - fail to login spice session with password + expire time
• BZ - 1138691 - Allow qemu-img to bypass the host cache (check, compare, convert, rebase, amend)
• BZ - 1140618 - Should replace "qemu-system-i386" by "/usr/libexec/qemu-kvm" in manpage of qemu-kvm for our official qemu-kvm build
• BZ - 1140742 - Enable native qemu support for Ceph
• BZ - 1141667 - Qemu crashed if reboot guest after hot remove AC97 sound device
• BZ - 1142290 - guest is stuck when setting balloon memory with large guest-stats-polling-interval
• BZ - 1144818 - CVE-2014-3640 qemu: slirp: NULL pointer deref in sosendto()
• BZ - 1155518 - qemu-kvm: undefined symbol: glfs_discard_async
• BZ - 1157641 - CVE-2014-7815 qemu: vnc: insufficient bits_per_pixel from the client sanitization
• BZ - 1160237 - qemu-img convert intermittently corrupts output images
• BZ - 1161563 - invalid QEMU NOTEs in vmcore that is dumped for multi-VCPU guests
• BZ - 1163075 - CVE-2014-7840 qemu: insufficient parameter validation during ram load
• BZ - 1169454 - CVE-2014-8106 qemu: cirrus: insufficient blit region checks
• BZ - 1175325 - Delete cow block driver
• BZ - 1180942 - qemu core dumped when unhotplug gpu card assigned to guest

CVEs

• CVE-2014-7840
• CVE-2014-7815
• CVE-2014-3640
• CVE-2014-8106

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Deployment_and_Administration_Guide/index.html