Synopsis:    Important: kernel security and bug fix update
Issue Date:  2012-02-09
CVE Numbers: CVE-2011-3638
             CVE-2011-4086
             CVE-2011-4127
             CVE-2012-0028
             CVE-2012-0207


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

This update fixes the following security issues:

* Using the SG_IO ioctl to issue SCSI requests to partitions or LVM volumes
resulted in the requests being passed to the underlying block device. If a
privileged user only had access to a single partition or LVM volume, they
could use this flaw to bypass those restrictions and gain read and write
access (and be able to issue other SCSI commands) to the entire block
device. (CVE-2011-4127, Important)

* A flaw was found in the way the Linux kernel handled robust list pointers
of user-space held futexes across exec() calls. A local, unprivileged user
could use this flaw to cause a denial of service or, eventually, escalate
their privileges. (CVE-2012-0028, Important)

* A flaw was found in the Linux kernel in the way splitting two extents in
ext4_ext_convert_to_initialized() worked. A local, unprivileged user with
the ability to mount and unmount ext4 file systems could use this flaw to
cause a denial of service. (CVE-2011-3638, Moderate)

* A flaw was found in the way the Linux kernel's journal_unmap_buffer()
function handled buffer head states. On systems that have an ext4 file
system with a journal mounted, a local, unprivileged user could use this
flaw to cause a denial of service. (CVE-2011-4086, Moderate)

* A divide-by-zero flaw was found in the Linux kernel's igmp_heard_query()
function. An attacker able to send certain IGMP (Internet Group Management
Protocol) packets to a target system could use this flaw to cause a denial
of service. (CVE-2012-0207, Moderate)

This update also fixes the following bugs:

* When a host was in recovery mode and a SCSI scan operation was initiated,
the scan operation failed and provided no error output. This bug has been
fixed and the SCSI layer now waits for recovery of the host to complete
scan operations for devices.

* SG_IO ioctls were not implemented correctly in the previous virtio-blk driver.
Sending an SG_IO ioctl request to a virtio-blk disk caused the sending thread
to enter an uninterruptible sleep state ("D" state). With this update, SG_IO
ioctls are rejected by the virtio-blk driver: the ioctl system call will simply
return an ENOTTY ("Inappropriate ioctl for device") error and the thread will
continue normally.

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-2.6.18-274.18.1.el5.i686.rpm
     kernel-debug-2.6.18-274.18.1.el5.i686.rpm
     kernel-debug-debuginfo-2.6.18-274.18.1.el5.i686.rpm
     kernel-debug-devel-2.6.18-274.18.1.el5.i686.rpm
     kernel-debuginfo-2.6.18-274.18.1.el5.i686.rpm
     kernel-debuginfo-common-2.6.18-274.18.1.el5.i686.rpm
     kernel-devel-2.6.18-274.18.1.el5.i686.rpm
     kernel-headers-2.6.18-274.18.1.el5.i386.rpm
     kernel-PAE-2.6.18-274.18.1.el5.i686.rpm
     kernel-PAE-debuginfo-2.6.18-274.18.1.el5.i686.rpm
     kernel-PAE-devel-2.6.18-274.18.1.el5.i686.rpm
     kernel-xen-2.6.18-274.18.1.el5.i686.rpm
     kernel-xen-debuginfo-2.6.18-274.18.1.el5.i686.rpm
     kernel-xen-devel-2.6.18-274.18.1.el5.i686.rpm
  noarch
     kernel-doc-2.6.18-274.18.1.el5.noarch.rpm
  x86_64
     kernel-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-debug-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-debug-debuginfo-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-debug-devel-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-debuginfo-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-debuginfo-common-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-devel-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-headers-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-xen-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-xen-debuginfo-2.6.18-274.18.1.el5.x86_64.rpm
     kernel-xen-devel-2.6.18-274.18.1.el5.x86_64.rpm

- Scientific Linux Development Team