kernel security update

CentOS Errata and Security Advisory CESA-2009:1243

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

These updated packages fix the following security issues:

• it was discovered that, when executing a new process, the clear_child_tid
  pointer in the Linux kernel is not cleared. If this pointer points to a
  writable portion of the memory of the new program, the kernel could corrupt
  four bytes of memory, possibly leading to a local denial of service or
  privilege escalation. (CVE-2009-2848, Important)

• a flaw was found in the way the do_sigaltstack() function in the Linux
  kernel copies the stack_t structure to user-space. On 64-bit machines, this
  flaw could lead to a four-byte information leak. (CVE-2009-2847, Moderate)

• a flaw was found in the ext4 file system code. A local attacker could use
  this flaw to cause a denial of service by performing a resize operation on
  a specially-crafted ext4 file system. (CVE-2009-0745, Low)

• multiple flaws were found in the ext4 file system code. A local attacker
  could use these flaws to cause a denial of service by mounting a
  specially-crafted ext4 file system. (CVE-2009-0746, CVE-2009-0747,
  CVE-2009-0748, Low)

These updated packages also include several hundred bug fixes for and
enhancements to the Linux kernel. Space precludes documenting each of these
changes in this advisory and users are directed to the Red Hat Enterprise
Linux 5.4 Release Notes for information on the most significant of these
changes:

http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Release_Notes/

Also, for details concerning every bug fixed in and every enhancement added
to the kernel for this release, see the kernel chapter in the Red Hat
Enterprise Linux 5.4 Technical Notes:

http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Technical_Notes/kernel.html

All Red Hat Enterprise Linux 5 users are advised to install these updated
packages, which address these vulnerabilities as well as fixing the bugs
and adding the enhancements noted in the Red Hat Enterprise Linux 5.4
Release Notes and Technical Notes. The system must be rebooted for this
update to take effect.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2009-September/078299.html
https://lists.centos.org/pipermail/centos-announce/2009-September/078300.html

Affected packages:
kernel
kernel-PAE
kernel-PAE-devel
kernel-debug
kernel-debug-devel
kernel-devel
kernel-doc
kernel-headers
kernel-xen
kernel-xen-devel

Upstream details at:
https://access.redhat.com/errata/RHSA-2009:1243