kernel security update

CentOS Errata and Security Advisory CESA-2014:0285

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

• A buffer overflow flaw was found in the way the qeth_snmp_command()
  function in the Linux kernel’s QETH network device driver implementation
  handled SNMP IOCTL requests with an out-of-bounds length. A local,
  unprivileged user could use this flaw to crash the system or, potentially,
  escalate their privileges on the system. (CVE-2013-6381, Important)

• A flaw was found in the way the ipc_rcu_putref() function in the Linux
  kernel’s IPC implementation handled reference counter decrementing.
  A local, unprivileged user could use this flaw to trigger an Out of Memory
  (OOM) condition and, potentially, crash the system. (CVE-2013-4483,
  Moderate)

• It was found that the Xen hypervisor implementation did not correctly
  check privileges of hypercall attempts made by HVM guests, allowing
  hypercalls to be invoked from protection rings 1 and 2 in addition to ring

0. A local attacker in an HVM guest able to execute code on privilege
   levels 1 and 2 could potentially use this flaw to further escalate their
   privileges in that guest. Note: Xen HVM guests running unmodified versions
   of Red Hat Enterprise Linux and Microsoft Windows are not affected by this
   issue because they are known to only use protection rings 0 (kernel) and 3
   (userspace). (CVE-2013-4554, Moderate)

• A flaw was found in the way the Linux kernel’s Adaptec RAID controller
  (aacraid) checked permissions of compat IOCTLs. A local attacker could use
  this flaw to bypass intended security restrictions. (CVE-2013-6383,
  Moderate)

• It was found that, under specific circumstances, a combination of write
  operations to write-combined memory and locked CPU instructions may cause a
  core hang on certain AMD CPUs (for more information, refer to AMD CPU
  erratum 793 linked in the References section). A privileged user in a guest
  running under the Xen hypervisor could use this flaw to cause a denial of
  service on the host system. This update adds a workaround to the Xen
  hypervisor implementation, which mitigates the AMD CPU issue. Note: this
  issue only affects AMD Family 16h Models 00h-0Fh Processors. Non-AMD CPUs
  are not vulnerable. (CVE-2013-6885, Moderate)

• It was found that certain protocol handlers in the Linux kernel’s
  networking implementation could set the addr_len value without initializing
  the associated data structure. A local, unprivileged user could use this
  flaw to leak kernel stack memory to user space using the recvmsg, recvfrom,
  and recvmmsg system calls. (CVE-2013-7263, Low)

• A flaw was found in the way the get_dumpable() function return value was
  interpreted in the ptrace subsystem of the Linux kernel. When
  ‘fs.suid_dumpable’ was set to 2, a local, unprivileged local user could
  use this flaw to bypass intended ptrace restrictions and obtain
  potentially sensitive information. (CVE-2013-2929, Low)

Red Hat would like to thank Vladimir Davydov of Parallels for reporting
CVE-2013-4483 and the Xen project for reporting CVE-2013-4554 and
CVE-2013-6885. Upstream acknowledges Jan Beulich as the original reporter
of CVE-2013-4554 and CVE-2013-6885.

This update also fixes several bugs and adds one enhancement.
Documentation for these changes will be available shortly from the
Technical Notes document linked to in the References section.

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add this
enhancement. The system must be rebooted for this update to take effect.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2014-March/082361.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-2014:0285