kernel security update

CentOS Errata and Security Advisory CESA-2010:0474

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

Security fixes:

• a NULL pointer dereference flaw was found in the Linux kernel NFSv4
  implementation. Several of the NFSv4 file locking functions failed to check
  whether a file had been opened on the server before performing locking
  operations on it. A local, unprivileged user on a system with an NFSv4
  share mounted could possibly use this flaw to cause a kernel panic (denial
  of service) or escalate their privileges. (CVE-2009-3726, Important)

• a flaw was found in the sctp_process_unk_param() function in the Linux
  kernel Stream Control Transmission Protocol (SCTP) implementation. A remote
  attacker could send a specially-crafted SCTP packet to an SCTP listening
  port on a target system, causing a kernel panic (denial of service).
  (CVE-2010-1173, Important)

• a race condition between finding a keyring by name and destroying a freed
  keyring was found in the Linux kernel key management facility. A local,
  unprivileged user could use this flaw to cause a kernel panic (denial of
  service) or escalate their privileges. (CVE-2010-1437, Important)

Red Hat would like to thank Simon Vallet for responsibly reporting
CVE-2009-3726; and Jukka Taimisto and Olli Jarva of Codenomicon Ltd, Nokia
Siemens Networks, and Wind River on behalf of their customer, for
responsibly reporting CVE-2010-1173.

Bug fixes:

• RHBA-2007:0791 introduced a regression in the Journaling Block Device
  (JBD). Under certain circumstances, removing a large file (such as 300 MB
  or more) did not result in inactive memory being freed, leading to the
  system having a large amount of inactive memory. Now, the memory is
  correctly freed. (BZ#589155)

• the timer_interrupt() routine did not scale lost real ticks to logical
  ticks correctly, possibly causing time drift for 64-bit Red Hat Enterprise
  Linux 4 KVM (Kernel-based Virtual Machine) guests that were booted with the
  “divider=x” kernel parameter set to a value greater than 1. “warning: many
  lost ticks” messages may have been logged on the affected guest systems.
  (BZ#590551)

• a bug could have prevented NFSv3 clients from having the most up-to-date
  file attributes for files on a given NFSv3 file system. In cases where a
  file type changed, such as if a file was removed and replaced with a
  directory of the same name, the NFSv3 client may not have noticed this
  change until stat(2) was called (for example, by running “ls -l”).
  (BZ#596372)

• RHBA-2007:0791 introduced bugs in the Linux kernel PCI-X subsystem. These
  could have caused a system deadlock on some systems where the BIOS set the
  default Maximum Memory Read Byte Count (MMRBC) to 4096, and that also use
  the Intel PRO/1000 Linux driver, e1000. Errors such as “e1000: eth[x]:
  e1000_clean_tx_irq: Detected Tx Unit Hang” were logged. (BZ#596374)

• an out of memory condition in a KVM guest, using the virtio-net network
  driver and also under heavy network stress, could have resulted in
  that guest being unable to receive network traffic. Users had to manually
  remove and re-add the virtio_net module and restart the network service
  before networking worked as expected. Such memory conditions no longer
  prevent KVM guests receiving network traffic. (BZ#597310)

• when an SFQ qdisc that limited the queue size to two packets was added to
  a network interface, sending traffic through that interface resulted in a
  kernel crash. Such a qdisc no longer results in a kernel crash. (BZ#597312)

• when an NFS client opened a file with the O_TRUNC flag set, it received
  a valid stateid, but did not use that stateid to perform the SETATTR call.
  Such cases were rejected by Red Hat Enterprise Linux 4 NFS servers with an
  “NFS4ERR_BAD_STATEID” error, possibly preventing some NFS clients from
  writing files to an NFS file system. (BZ#597314)

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.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2010-August/079096.html
https://lists.centos.org/pipermail/centos-announce/2010-August/079097.html
https://lists.centos.org/pipermail/centos-announce/2010-August/079112.html
https://lists.centos.org/pipermail/centos-announce/2010-August/079113.html

Affected packages:
kernel
kernel-devel
kernel-doc
kernel-hugemem
kernel-hugemem-devel
kernel-largesmp
kernel-largesmp-devel
kernel-smp
kernel-smp-devel
kernel-xenU
kernel-xenU-devel

Upstream details at:
https://access.redhat.com/errata/RHSA-2010:0474