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Vulnerability of Linux kernel: denial of service via memory_hotplug

Synthesis of the vulnerability 

A local attacker can deplete the memory, in order to force the kernel to dereference a NULL pointer, which stops it.
Vulnerable software: Linux, openSUSE, RHEL, SUSE Linux Enterprise Desktop, SLES.
Severity of this announce: 1/4.
Creation date: 12/11/2012.
Références of this computer vulnerability: BID-56527, CERTA-2013-AVI-412, CVE-2012-5517, MDVSA-2013:194, openSUSE-SU-2013:0925-1, openSUSE-SU-2013:0927-1, RHSA-2012:1580-01, SUSE-SU-2012:1679-1, SUSE-SU-2013:0786-1, VIGILANCE-VUL-12127.

Description of the vulnerability 

The mm/memory_hotplug.c file implements features to add or remove memory. These features are used by:
 - anti-fragmentation : huge page, etc.
 - logical changes: virtualization, Memory capacity on Demand
 - physical changes: power saving, hardware partitioning, etc.

The online_pages() function of the mm/memory_hotplug.c file adds a memory zone, and rebuilds the zone list. However, this zone is not added to some nodes. When the system will use all its memory, a NULL pointer will then be dereferenced.

A local attacker can therefore deplete the memory, on a system which used online_pages(), in order to force the kernel to dereference a NULL pointer, which stops it.
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This computer threat bulletin impacts software or systems such as Linux, openSUSE, RHEL, SUSE Linux Enterprise Desktop, SLES.

Our Vigil@nce team determined that the severity of this security threat is low.

The trust level is of type confirmed by the editor, with an origin of user shell.

An attacker with a expert ability can exploit this computer vulnerability alert.

Solutions for this threat 

Linux kernel: patch for memory_hotplug.
A patch is available in information sources.

Mandriva BS 1: new kernel packages.
New packages are available:
  kernel-server-3.4.52-1.1.mbs1

openSUSE 11.4: new kernel-3.0.58 packages (10/06/2013).
New packages are available:
  kernel-3.0.58-30.2

openSUSE 11.4: new kernel-3.0.74 packages (10/06/2013).
New packages are available:
  kernel-3.0.74-34.1

RHEL 6: new kernel packages.
New packages are available:
  kernel-2.6.32-279.19.1

SUSE LE 11: new kernel packages (20/12/2012 ).
New packages are available:
  kernel-default-3.0.51-0.7.9.1

SUSE LE Real Time: new kernel-rt packages.
New packages are available:
  kernel-rt-3.0.74.rt98-0.6.2.1
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