7.8 - RHSA-2013:0911

Problem Description:

Updated kernel packages that fix three security issues, several bugs, and add one enhancement are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team 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.

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 KVM (Kernel-based Virtual Machine) initialized a guest's registered pv_eoi (paravirtualized end-of-interrupt) indication flag when entering the guest. An unprivileged guest user could potentially use this flaw to crash the host. (CVE-2013-1935, Important)

* A missing sanity check was found in the kvm_set_memory_region() function in KVM, allowing a user-space process to register memory regions pointing to the kernel address space. A local, unprivileged user could use this flaw to escalate their privileges. (CVE-2013-1943, Important)

* A double free flaw was found in the Linux kernel's Virtual Ethernet Tunnel driver (veth). A remote attacker could possibly use this flaw to crash a target system. (CVE-2013-2017, Moderate)

Red Hat would like to thank IBM for reporting the CVE-2013-1935 issue and Atzm WATANABE of Stratosphere Inc. for reporting the CVE-2013-2017 issue. The CVE-2013-1943 issue was discovered by Michael S. Tsirkin of Red Hat.

This update also fixes several bugs and adds one enhancement. 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 add this enhancement. 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/):

949981 - CVE-2013-1935 kernel: kvm: pv_eoi guest updates with interrupts disabled 950490 - CVE-2013-1943 kernel: kvm: missing check in kvm_set_memory_region() 957705 - CVE-2013-2017 kernel: veth: double-free flaw in case of congestion