4.9 - RHSA-2013:0223

Problem Description:

Updated kernel packages that fix three 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:

* It was found that a deadlock could occur in the Out of Memory (OOM) killer. A process could trigger this deadlock by consuming a large amount of memory, and then causing request_module() to be called. A local, unprivileged user could use this flaw to cause a denial of service (excessive memory consumption). (CVE-2012-4398, Moderate)

* A flaw was found in the way the KVM (Kernel-based Virtual Machine) subsystem handled guests attempting to run with the X86_CR4_OSXSAVE CPU feature flag set. On hosts without the XSAVE CPU feature, a local, unprivileged user could use this flaw to crash the host system. (The "grep --color xsave /proc/cpuinfo" command can be used to verify if your system has the XSAVE CPU feature.) (CVE-2012-4461, Moderate)

* A memory disclosure flaw was found in the way the load_script() function in the binfmt_script binary format handler handled excessive recursions. A local, unprivileged user could use this flaw to leak kernel stack memory to user-space by executing specially-crafted scripts. (CVE-2012-4530, Low)

Red Hat would like to thank Tetsuo Handa for reporting CVE-2012-4398, and Jon Howell for reporting CVE-2012-4461.

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/):

853474 - CVE-2012-4398 kernel: request_module() OOM local DoS 862900 - CVE-2012-4461 kernel: kvm: invalid opcode oops on SET_SREGS with OSXSAVE bit set 865305 - fuse: backport scatter-gather direct IO [rhel-6.3.z] 868285 - CVE-2012-4530 kernel: stack disclosure in binfmt_script load_script()