RHEL 6 : kernel (RHSA-2012:0743)

This script is Copyright (C) 2012-2014 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

Updated kernel packages that fix multiple security issues and several
bugs are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS)
base scores, which give detailed severity ratings, are available for
each vulnerability from the CVE links in the References section.

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

This update fixes the following security issues :

* A local, unprivileged user could use an integer overflow flaw in
drm_mode_dirtyfb_ioctl() to cause a denial of service or escalate
their privileges. (CVE-2012-0044, Important)

* A buffer overflow flaw was found in the macvtap device driver, used
for creating a bridged network between the guest and the host in KVM
(Kernel-based Virtual Machine) environments. A privileged guest user
in a KVM guest could use this flaw to crash the host. Note: This issue
only affected hosts that have the vhost_net module loaded with the
experimental_zcopytx module option enabled (it is not enabled by
default), and that also have macvtap configured for at least one
guest. (CVE-2012-2119, Important)

* When a set user ID (setuid) application is executed, certain
personality flags for controlling the application's behavior are
cleared (that is, a privileged application will not be affected by
those flags). It was found that those flags were not cleared if the
application was made privileged via file system capabilities. A local,
unprivileged user could use this flaw to change the behavior of such
applications, allowing them to bypass intended restrictions. Note that
for default installations, no application shipped by Red Hat for Red
Hat Enterprise Linux is made privileged via file system capabilities.
(CVE-2012-2123, Important)

* It was found that the data_len parameter of the
sock_alloc_send_pskb() function in the Linux kernel's networking
implementation was not validated before use. A privileged guest user
in a KVM guest could use this flaw to crash the host or, possibly,
escalate their privileges on the host. (CVE-2012-2136, Important)

* A buffer overflow flaw was found in the setup_routing_entry()
function in the KVM subsystem of the Linux kernel in the way the
Message Signaled Interrupts (MSI) routing entry was handled. A local,
unprivileged user could use this flaw to cause a denial of service or,
possibly, escalate their privileges. (CVE-2012-2137, Important)

* A race condition was found in the Linux kernel's memory management
subsystem in the way pmd_none_or_clear_bad(), when called with
mmap_sem in read mode, and Transparent Huge Pages (THP) page faults
interacted. A privileged user in a KVM guest with the ballooning
functionality enabled could potentially use this flaw to crash the
host. A local, unprivileged user could use this flaw to crash the
system. (CVE-2012-1179, Moderate)

* A flaw was found in the way device memory was handled during guest
device removal. Upon successful device removal, memory used by the
device was not properly unmapped from the corresponding IOMMU or
properly released from the kernel, leading to a memory leak. A
malicious user on a KVM host who has the ability to assign a device to
a guest could use this flaw to crash the host. (CVE-2012-2121,
Moderate)

* A flaw was found in the Linux kernel's Reliable Datagram Sockets
(RDS) protocol implementation. A local, unprivileged user could use
this flaw to cause a denial of service. (CVE-2012-2372, Moderate)

* A race condition was found in the Linux kernel's memory management
subsystem in the way pmd_populate() and pte_offset_map_lock()
interacted on 32-bit x86 systems with more than 4GB of RAM. A local,
unprivileged user could use this flaw to cause a denial of service.
(CVE-2012-2373, Moderate)

Red Hat would like to thank Chen Haogang for reporting CVE-2012-0044.

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

Users should upgrade to these updated packages, which contain
backported patches to correct these issues, and fix the bugs noted in
the Technical Notes. The system must be rebooted for this update to
take effect.

See also :

https://www.redhat.com/security/data/cve/CVE-2012-0044.html
https://www.redhat.com/security/data/cve/CVE-2012-1179.html
https://www.redhat.com/security/data/cve/CVE-2012-2119.html
https://www.redhat.com/security/data/cve/CVE-2012-2121.html
https://www.redhat.com/security/data/cve/CVE-2012-2123.html
https://www.redhat.com/security/data/cve/CVE-2012-2136.html
https://www.redhat.com/security/data/cve/CVE-2012-2137.html
https://www.redhat.com/security/data/cve/CVE-2012-2372.html
https://www.redhat.com/security/data/cve/CVE-2012-2373.html
https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/
http://rhn.redhat.com/errata/RHSA-2012-0743.html

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.2
(CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 6.3
(CVSS2#E:ND/RL:OF/RC:C)
Public Exploit Available : false