Red Hat 6: RHSA-2013:0622-01 Important: Kernel-Rt Privilege Escalation

The kernel-rt 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 file permission checks for the "/dev/cpu/[x]/msr" files were performed in restricted root environments (for example, when using a capability-based security model). A local user with the ability to write to these files could use this flaw to escalate their privileges to kernel level, for example, by writing to the SYSENTER_EIP_MSR register. (CVE-2013-0268, Important)
* A race condition was found in the way the Linux kernel's ptrace implementation handled PTRACE_SETREGS requests when the debuggee was woken due to a SIGKILL signal instead of being stopped. A local, unprivileged user could use this flaw to escalate their privileges. (CVE-2013-0871, Important)
* An out-of-bounds access flaw was found in the way SOCK_DIAG_BY_FAMILY Netlink messages were processed in the Linux kernel. A local, unprivileged user could use this flaw to escalate their privileges. (CVE-2013-1763, Important)
* It was found that the default SCSI command filter does not accommodate commands that overlap across device classes. A privileged guest user could potentially use this flaw to write arbitrary data to a LUN that is passed-through as read-only. (CVE-2012-4542, Moderate)
* A flaw was found in the way the __skb_recv_datagram() function in the Linux kernel processed payload-less socket buffers (skb) when the MSG_PEEK option was requested. A local, unprivileged user could use this flaw to cause a denial of service (infinite loop). (CVE-2013-0290, Moderate)
The CVE-2012-4542 issue was discovered by Paolo Bonzini of Red Hat.
This update also fixes the following bugs:
* There was high contention on run-queue lock when load balancing before idling, causing latency spikes on high CPU core count systems. With this update, IPI is used to send notification to cores with pending work, and the cores push the work rather than trying to pull it, resolving this issue. (BZ#858396)
* Previously, ACPI lock was converted to an rt_mutex, leading to a traceback when scheduling while atomic. With this update, ACPI lock has been converted back to a raw spinlock. (BZ#909965)
* Fibre Channel (FC)/iSCSI device state was set to off-line and after a timeout, not set back to running. Such a device would not come back online after a fast_io_fail or timeout. With this update, an explicit check for the device being offline has been added, and the device is set back to running when re-initializing, allowing devices to recover after a failure or timeout. (BZ#912942)
Users should upgrade to these updated packages, which correct these issues. The system must be rebooted for this update to take effect.