Articles / Ubuntu: Security update for…

Ubuntu: Security update for the Linux kernel

A flaw was discovered in the macvtap device driver, which is used in KVM (Kernel-based Virtual Machine) to create a network bridge between host and guest. A privleged user in a guest could exploit this flaw to crash the host, if the vhost_net module is loaded with the experimental_zcopytx option enabled. An error was discovered in the network TUN/TAP device implementation. A local user with access to the TUN/TAP interface (which is not available to unprivileged users until granted by a root user) could exploit this flaw to crash the system or potential gain administrative privileges. A flaw was found in how the KVM (Kernel-based Virtual Machine) subsystem handled MSI (Message Signaled Interrupts). A local unprivileged user could exploit this flaw to cause a denial of service or potentially elevate privileges.

A flaw was found in the Reliable Datagram Sockets (RDS) protocol implementation. A local, unprivileged user could use this flaw to cause a denial of service. Ulrich Obergfell discovered an error in the memory management subsystem on 32 bit PAE systems with more than 4GB of memory installed. A local unprivileged user could exploit this flaw to crash the system. Dan Rosenberg discovered flaws in the NCI (Near Field Communication Controller Interface). A remote attacker could exploit these flaws to crash the system or potentially execute privileged code.

A flaw was discovered in the epoll system call. An unprivileged local user could use this flaw to crash the system. Some errors where discovered in the UDF file system, which is used to mount some CD-ROMs and DVDs. An unprivileged local user could use these flaws to crash the system.

Updated packages are available from security.ubuntu.com.

==========================================================================
Ubuntu Security Notice USN-1529-1
August 10, 2012

linux vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 12.04 LTS

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

A flaw was discovered in the Linux kernel's macvtap device driver, which is
used in KVM (Kernel-based Virtual Machine) to create a network bridge
between host and guest. A privleged user in a guest could exploit this flaw
to crash the host, if the vhost_net module is loaded with the
experimental_zcopytx option enabled. (CVE-2012-2119)

An error was discovered in the Linux kernel's network TUN/TAP device
implementation. A local user with access to the TUN/TAP interface (which is
not available to unprivileged users until granted by a root user) could
exploit this flaw to crash the system or potential gain administrative
privileges. (CVE-2012-2136)

A flaw was found in how the Linux kernel's KVM (Kernel-based Virtual
Machine) subsystem handled MSI (Message Signaled Interrupts). A local
unprivileged user could exploit this flaw to cause a denial of service or
potentially elevate privileges. (CVE-2012-2137)

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)

Ulrich Obergfell discovered an error in the Linux kernel's memory
management subsystem on 32 bit PAE systems with more than 4GB of memory
installed. A local unprivileged user could exploit this flaw to crash the
system. (CVE-2012-2373)

Dan Rosenberg discovered flaws in the Linux kernel's NCI (Near Field
Communication Controller Interface). A remote attacker could exploit these
flaws to crash the system or potentially execute privileged code.
(CVE-2012-3364)

A flaw was discovered in the Linux kernel's epoll system call. An
unprivileged local user could use this flaw to crash the system.
(CVE-2012-3375)

Some errors where discovered in the Linux kernel's UDF file system, which
is used to mount some CD-ROMs and DVDs. An unprivileged local user could
use these flaws to crash the system. (CVE-2012-3400)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 12.04 LTS:
 linux-image-3.2.0-29-generic    3.2.0-29.46
 linux-image-3.2.0-29-generic-pae  3.2.0-29.46
 linux-image-3.2.0-29-highbank   3.2.0-29.46
 linux-image-3.2.0-29-omap       3.2.0-29.46
 linux-image-3.2.0-29-powerpc-smp  3.2.0-29.46
 linux-image-3.2.0-29-powerpc64-smp  3.2.0-29.46
 linux-image-3.2.0-29-virtual    3.2.0-29.46

After a standard system update you need to reboot your computer to make
all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed. If
you use linux-restricted-modules, you have to update that package as
well to get modules which work with the new kernel version. Unless you
manually uninstalled the standard kernel metapackages (e.g. linux-generic,
linux-server, linux-powerpc), a standard system upgrade will automatically
perform this as well.

References:
 http://www.ubuntu.com/usn/usn-1529-1
 CVE-2012-2119, CVE-2012-2136, CVE-2012-2137, CVE-2012-2372,
 CVE-2012-2373, CVE-2012-3364, CVE-2012-3375, CVE-2012-3400

Package Information:
 https://launchpad.net/ubuntu/+source/linux/3.2.0-29.46
Screenshot

Project Spotlight

Kigo Video Converter Ultimate for Mac

A tool for converting and editing videos.

Screenshot

Project Spotlight

Kid3

An efficient tagger for MP3, Ogg/Vorbis, and FLAC files.