RHSA-2012:0571 - Security Advisory

Topic

Updated kernel packages that fix two security issues and several bugs are
now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
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

The kernel packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issues:

• A flaw was found in the way the Linux kernel's journal_unmap_buffer()

function handled buffer head states. On systems that have an ext4 file
system with a journal mounted, a local, unprivileged user could use this
flaw to cause a denial of service. (CVE-2011-4086, Moderate)

• A flaw was found in the way the KVM_CREATE_IRQCHIP ioctl was handled.

Calling this ioctl when at least one virtual CPU (VCPU) already existed
could lead to a NULL pointer dereference later when the VCPU is scheduled
to run. A local, unprivileged user on a KVM host could use this flaw to
crash the host. (CVE-2012-1601, Moderate)

This update also fixes several bugs. Documentation for these changes will
be available shortly from the Technical Notes document linked to in the
References section.

Users should upgrade to these updated packages, which contain backported
patches to correct these issues, and fix the bugs noted in the Technical
Notes. The system must be rebooted 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/knowledge/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.2 i386
• Red Hat Enterprise Linux Server - AUS 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.2 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.2 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.2 i386
• Red Hat Storage 2.0 x86_64
• Red Hat Gluster Storage Server for On-premise 2.0 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.0 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 749143 - CVE-2011-4086 kernel: jbd2: unmapped buffer with _Unwritten or _Delay flags set can lead to DoS
• BZ - 808199 - CVE-2012-1601 kernel: kvm: irqchip_in_kernel() and vcpu->arch.apic inconsistency
• BZ - 809374 - AMD IOMMU driver hands out dma handles that are in the MSI address range [rhel-6.2.z]
• BZ - 811135 - readdir64_r calls fail with ELOOP [rhel-6.2.z]
• BZ - 811299 - Fix RPC priority queue wake up all tasks processing [rhel-6.2.z]

CVEs

• CVE-2011-4086
• CVE-2012-1601

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.2_Technical_Notes/kernel.html#RHSA-2012-0571