RHSA-2014:0704 - Security Advisory

Topic

Updated qemu-kvm packages that fix one security issue and several bugs are
now available for Red Hat Enterprise Linux 7.

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.

Description

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

An out-of-bounds memory access flaw was found in the way QEMU's IDE device
driver handled the execution of SMART EXECUTE OFFLINE commands.
A privileged guest user could use this flaw to corrupt QEMU process memory
on the host, which could potentially result in arbitrary code execution on
the host with the privileges of the QEMU process. (CVE-2014-2894)

This update also fixes the following bugs:

• Prior to this update, a bug in the migration code caused the following

error on specific machine types: after a Red Hat Enterprise Linux 6.5 guest
was migrated from a Red Hat Enterprise Linux 6.5 host to a Red Hat
Enterprise Linux 7.0 host and then restarted, the boot failed and the guest
automatically restarted. Thus, the guest entered an endless loop. With this
update, the migration code has been fixed and the Red Hat Enterprise Linux
6.5 guests migrated in the aforementioned scenario now boot properly.
(BZ#1091322)

• Due to a regression bug in the iSCSI driver, the 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 regression and the "write same" command now functions in guest
mode under iSCSI as intended. (BZ#1090978)

• Due to a mismatch in interrupt request (IRQ) routing, migration of a Red

Hat Enterprise Linux 6.5 guest from a Red Hat Enterprise Linux 6.5 host to
a Red Hat Enterprise Linux 7.0 host could produce a call trace.
This happened if memory ballooning and a Universal Host Control Interface
(UHCI) device were used at the same time on certain machine types.
With this patch, the IRQ routing mismatch has been amended and the
described migration now proceeds as expected. (BZ#1090981)

• Previously, an internal error prevented KVM from executing a CPU hot plug

on a Red Hat Enterprise Linux 7 guest running on a Red Hat Enterprise Linux
7 host. This update addresses the internal error and CPU hot plugging in
the described scenario now functions correctly. (BZ#1094820)

All qemu-kvm users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. 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.

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
https://access.redhat.com/site/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 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 Server - Extended Life Cycle Support 7 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux for Scientific Computing 7 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 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 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 7.5 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 for x86_64 - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - 1087971 - CVE-2014-2894 QEMU: out of bounds buffer accesses, guest triggerable via IDE SMART
• BZ - 1090978 - qemu-kvm: iSCSI: Failure. SENSE KEY:ILLEGAL_REQUEST(5) ASCQ:INVALID_FIELD_IN_CDB(0x2400)
• BZ - 1090981 - Guest hits call trace migrate from RHEL6.5 to RHEL7.0 host with -M 6.1 & balloon & uhci device
• BZ - 1091322 - fail to reboot guest after migration from RHEL6.5 host to RHEL7.0 host
• BZ - 1094820 - Hot plug CPU not working with RHEL6 machine types running on RHEL7 host.

CVEs

• CVE-2014-2894

References

• https://access.redhat.com/security/updates/classification/#moderate