1.5 - RHSA-2013:1790

Problem Description:

Updated kernel packages that fix one security issue and several bugs are now available for Red Hat Enterprise Linux 5.

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 (v. 5 server) - i386, ia64, noarch, ppc, s390x, x86_64 Red Hat Enterprise Linux Desktop (v. 5 client) - i386, noarch, x86_64

3. Description:

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

* An information leak flaw was found in the way the Xen hypervisor handled error conditions when reading guest memory during certain guest-originated operations, such as port or memory mapped I/O writes. A privileged user in a fully-virtualized guest could use this flaw to leak hypervisor stack memory to a guest. (CVE-2013-4355, Moderate)

Red Hat would like to thank the Xen project for reporting this issue.

This update also fixes the following bugs:

* A previous fix to the kernel did not contain a memory barrier in the percpu_up_write() function. Consequently, under certain circumstances, a race condition could occur leading to memory corruption and a subsequent kernel panic. This update introduces a new memory barrier pair, light_mb() and heavy_mb(), for per-CPU basis read and write semaphores (percpu-rw-semaphores) ensuring that the race condition can no longer occur. In addition, the read path performance of "percpu-rw-semaphores" has been improved. (BZ#1014715)

* Due to a bug in the tg3 driver, systems that had the Wake-on-LAN (WOL) feature enabled on their NICs could not have been woken up from suspension or hibernation using WOL. A missing pci_wake_from_d3() function call has been added to the tg3 driver, which ensures that WOL functions properly by setting the PME_ENABLE bit. (BZ#1014973)

* Due to an incorrect test condition in the mpt2sas driver, the driver was unable to catch failures to map a SCSI scatter-gather list. The test condition has been corrected so that the mpt2sas driver now handles SCSI scatter-gather mapping failures as expected. (BZ#1018458)

* A previous patch to the kernel introduced the "VLAN tag re-insertion" workaround to resolve a problem with incorrectly handled VLAN-tagged packets with no assigned VLAN group while the be2net driver was in promiscuous mode. However, this solution led to packet corruption and a subsequent kernel oops if such a processed packed was a GRO packet. Therefore, a patch has been applied to restrict VLAN tag re-insertion only to non-GRO packets. The be2net driver now processes VLAN-tagged packets with no assigned VLAN group correctly in this situation. (BZ#1023348)

All kernel users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. 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/site/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 (https://bugzilla.redhat.com/):

1009598 - CVE-2013-4355 Kernel: Xen: Xsa-63: information leak via I/O instruction emulation