Synopsis:    Important: kernel security update
Issue Date:  2012-06-12
CVE Numbers: CVE-2012-0217
             CVE-2012-2934


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 the Xen hypervisor implementation as shipped with
Scientific Linux 5 did not properly restrict the syscall return
addresses in the sysret return path to canonical addresses. An unprivileged
user in a 64-bit para-virtualized guest, that is running on a 64-bit host
that has an Intel CPU, could use this flaw to crash the host or,
potentially, escalate their privileges, allowing them to execute arbitrary
code at the hypervisor level. (CVE-2012-0217, Important)

* It was found that guests could trigger a bug in earlier AMD CPUs, leading
to a CPU hard lockup, when running on the Xen hypervisor implementation. An
unprivileged user in a 64-bit para-virtualized guest could use this flaw to
crash the host. Warning: After installing this update, hosts that are using
an affected AMD CPU (refer to upstream bug #824966 for a list) will
fail to boot. In order to boot such hosts, the new kernel parameter,
allow_unsafe, can be used ("allow_unsafe=on"). This option should only be
used with hosts that are running trusted guests, as setting it to "on"
reintroduces the flaw (allowing guests to crash the host). (CVE-2012-2934,
Moderate)

Note: For Scientific Linux guests, only privileged guest users can
exploit the CVE-2012-0217 and CVE-2012-2934 issues.

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. The system must be rebooted for this
update to take effect.

SL5:
  i386
     kernel-2.6.18-308.8.2.el5.i686.rpm
     kernel-debug-2.6.18-308.8.2.el5.i686.rpm
     kernel-debug-debuginfo-2.6.18-308.8.2.el5.i686.rpm
     kernel-debug-devel-2.6.18-308.8.2.el5.i686.rpm
     kernel-debuginfo-2.6.18-308.8.2.el5.i686.rpm
     kernel-debuginfo-common-2.6.18-308.8.2.el5.i686.rpm
     kernel-devel-2.6.18-308.8.2.el5.i686.rpm
     kernel-headers-2.6.18-308.8.2.el5.i386.rpm
     kernel-PAE-2.6.18-308.8.2.el5.i686.rpm
     kernel-PAE-debuginfo-2.6.18-308.8.2.el5.i686.rpm
     kernel-PAE-devel-2.6.18-308.8.2.el5.i686.rpm
     kernel-xen-2.6.18-308.8.2.el5.i686.rpm
     kernel-xen-debuginfo-2.6.18-308.8.2.el5.i686.rpm
     kernel-xen-devel-2.6.18-308.8.2.el5.i686.rpm
  noarch
     kernel-doc-2.6.18-308.8.2.el5.noarch.rpm
  x86_64
     kernel-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-debug-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-debug-debuginfo-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-debug-devel-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-debuginfo-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-debuginfo-common-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-devel-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-headers-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-xen-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-xen-debuginfo-2.6.18-308.8.2.el5.x86_64.rpm
     kernel-xen-devel-2.6.18-308.8.2.el5.x86_64.rpm

- Scientific Linux Development Team