5.2 - RHSA-2014:0108

Problem Description:

Updated kernel packages that fix one security issue and three 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. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link 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.

* It was found that the Xen hypervisor did not always lock 'page_alloc_lock' and 'grant_table.lock' in the same order. This could potentially lead to a deadlock. A malicious guest administrator could use this flaw to cause a denial of service on the host. (CVE-2013-4494, Moderate)

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

This update also fixes the following bugs:

* A recent patch to the CIFS code that introduced the NTLMSSP (NT LAN Manager Security Support Provider) authentication mechanism caused a regression in CIFS behavior. As a result of the regression, an encryption key that is returned during the SMB negotiation protocol response was only used for the first session that was created on the SMB client. Any subsequent mounts to the same server did not use the encryption key returned by the initial negotiation with the server. As a consequence, it was impossible to mount multiple SMB shares with different credentials to the same server. A patch has been applied to correct this problem so that an encryption key or a server challenge is now provided for every SMB session during the SMB negotiation protocol response. (BZ#1029865)

* The igb driver previously used a 16-bit mask when writing values of the flow control high-water mark to hardware registers on a network device. Consequently, the values were truncated on some network devices, disrupting the flow control. A patch has been applied to the igb driver so that it now uses a 32-bit mask as expected. (BZ#1041694)

* The IPMI driver did not properly handle kernel panic messages. Consequently, when a kernel panic occurred on a system that was utilizing IPMI without Kdump being set up, a second kernel panic could be triggered. A patch has been applied to the IPMI driver to fix this problem, and a message handler now properly waits for a response to panic event messages. (BZ#1049731)

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/):

1026243 - CVE-2013-4494 kernel: xen: Lock order reversal between page allocation and grant table locks