Important: kernel security and bug fix update

Updated kernel packages that fix multiple security issues and various bugs
are now available for Red Hat Enterprise Linux 5.3 Extended Update Support.

This update has been rated as having important security impact by the Red
Hat Security Response Team.

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

This update fixes the following security issues:

* a system with SELinux enforced was more permissive in allowing local
users in the unconfined_t domain to map low memory areas even if the
mmap_min_addr restriction was enabled. This could aid in the local
exploitation of NULL pointer dereference bugs. (CVE-2009-2695, Important)

* a NULL pointer dereference flaw was found in each of the following
functions in the Linux kernel: pipe_read_open(), pipe_write_open(), and
pipe_rdwr_open(). When the mutex lock is not held, the i_pipe pointer could
be released by other processes before it is used to update the pipe's
reader and writer counters. This could lead to a local denial of service or
privilege escalation. (CVE-2009-3547, Important)

This update also fixes the following bugs:

* a caching bug in nfs_readdir() has been resolved. This may have caused
parts of directory listings to become stale, as they came from cached data
when they should not have, possibly causing NFS clients to see duplicate
files or not see all files in a directory. (BZ#526959)

* a bug prevented the pciehp driver from detecting PCI Express hot plug
slots on some systems. (BZ#530381)

* when a process attempted to read from a page that had first been accessed
by writing to part of it (via write(2)), the NFS client needed to flush the
modified portion of the page out to the server, and then read the entire
page back in. This flush caused performance issues. (BZ#521243)

* a deadlock was found in the cciss driver. In rare cases, this caused an
NMI lockup during boot. Messages such as "cciss: controller cciss[x]
failed, stopping." and "cciss[x]: controller not responding." may have been
displayed on the console. (BZ#525728)

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.

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

517830 - CVE-2009-2695 kernel: SELinux and mmap_min_addr
521243 - Read/Write NFS I/O performance degraded by FLUSH_STABLE page flushing [rhel-5.3.z]
525728 - cciss: spinlock deadlock causes NMI on HP systems [rhel-5.3.z]
526959 - [NetApp 5.5 bug] nfs_readdir() may fail to return all the files in the directory [rhel-5.3.z]
530381 - [5.3] PCIe hotplug slot detection failure [rhel-5.3.z]
530490 - CVE-2009-3547 kernel: fs: pipe.c null pointer dereference

https://www.redhat.com/security/data/cve/CVE-2009-2695.html
https://www.redhat.com/security/data/cve/CVE-2009-3547.html
http://www.redhat.com/security/updates/classification/#important
http://kbase.redhat.com/faq/docs/DOC-18042
http://kbase.redhat.com/faq/docs/DOC-20481