4.9 - RHSA-2012:0571

Problem Description:

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64 Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64 Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64 Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64 Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64 Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, x86_64

3. 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.

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 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.

5. Bugs fixed (http://bugzilla.redhat.com/):

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