(RHSA-2010:0606) Important: kernel security and bug fix update

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

This update fixes the following security issues:

• a flaw was found in the CIFSSMBWrite() function in the Linux kernel
  Common Internet File System (CIFS) implementation. A remote attacker could
  send a specially-crafted SMB response packet to a target CIFS client,
  resulting in a kernel panic (denial of service). (CVE-2010-2248, Important)

• buffer overflow flaws were found in the Linux kernel’s implementation of
  the server-side External Data Representation (XDR) for the Network File
  System (NFS) version 4. An attacker on the local network could send a
  specially-crafted large compound request to the NFSv4 server, which could
  possibly result in a kernel panic (denial of service) or, potentially, code
  execution. (CVE-2010-2521, Important)

This update also fixes the following bug:

• the rpc_call_async() function in the SUN Remote Procedure Call (RPC)
  subsystem in the Linux kernel had a reference counting bug. In certain
  situations, some Network Lock Manager (NLM) messages may have triggered
  this bug on NFSv2 and NFSv3 servers, leading to a kernel panic (with
  “kernel BUG at fs/lockd/host.c:[xxx]!” logged to “/var/log/messages”).
  (BZ#612962)

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.