kernel security update

CentOS Errata and Security Advisory CESA-2010:0723

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

This update fixes the following security issues:

• A buffer overflow flaw was found in the ecryptfs_uid_hash() function in
  the Linux kernel eCryptfs implementation. On systems that have the eCryptfs
  netlink transport (Red Hat Enterprise Linux 5 does) or where the
  “/dev/ecryptfs” file has world writable permissions (which it does not, by
  default, on Red Hat Enterprise Linux 5), a local, unprivileged user could
  use this flaw to cause a denial of service or possibly escalate their
  privileges. (CVE-2010-2492, Important)

• A miscalculation of the size of the free space of the initial directory
  entry in a directory leaf block was found in the Linux kernel Global File
  System 2 (GFS2) implementation. A local, unprivileged user with write
  access to a GFS2-mounted file system could perform a rename operation on
  that file system to trigger a NULL pointer dereference, possibly resulting
  in a denial of service or privilege escalation. (CVE-2010-2798, Important)

• A flaw was found in the Xen hypervisor implementation when running a
  system that has an Intel CPU without Extended Page Tables (EPT) support.
  While attempting to dump information about a crashing fully-virtualized
  guest, the flaw could cause the hypervisor to crash the host as well. A
  user with permissions to configure a fully-virtualized guest system could
  use this flaw to crash the host. (CVE-2010-2938, Moderate)

• Information leak flaws were found in the Linux kernel’s Traffic Control
  Unit implementation. A local attacker could use these flaws to cause the
  kernel to leak kernel memory to user-space, possibly leading to the
  disclosure of sensitive information. (CVE-2010-2942, Moderate)

• A flaw was found in the Linux kernel’s XFS file system implementation.
  The file handle lookup could return an invalid inode as valid. If an XFS
  file system was mounted via NFS (Network File System), a local attacker
  could access stale data or overwrite existing data that reused the inodes.
  (CVE-2010-2943, Moderate)

• An integer overflow flaw was found in the extent range checking code in
  the Linux kernel’s ext4 file system implementation. A local, unprivileged
  user with write access to an ext4-mounted file system could trigger this
  flaw by writing to a file at a very large file offset, resulting in a local
  denial of service. (CVE-2010-3015, Moderate)

• An information leak flaw was found in the Linux kernel’s USB
  implementation. Certain USB errors could result in an uninitialized kernel
  buffer being sent to user-space. An attacker with physical access to a
  target system could use this flaw to cause an information leak.
  (CVE-2010-1083, Low)

Red Hat would like to thank Andre Osterhues for reporting CVE-2010-2492;
Grant Diffey of CenITex for reporting CVE-2010-2798; Toshiyuki Okajima for
reporting CVE-2010-3015; and Marcus Meissner for reporting CVE-2010-1083.

This update also fixes several bugs. Documentation for these bug fixes will
be available shortly from the Technical Notes document linked to in the
References.

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-September/079192.html
https://lists.centos.org/pipermail/centos-announce/2010-September/079193.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-2010:0723