USN-1644-1: Linux kernel vulnerabilities

30 November 2012

Several security issues were fixed in the kernel.

Releases

Packages

  • linux - Linux kernel

Details

Brad Spengler discovered a flaw in the Linux kernel's uname system call. An
unprivileged user could exploit this flaw to read kernel stack memory.
(CVE-2012-0957)

Dmitry Monakhov reported a race condition flaw the Linux ext4 filesystem
that can expose stale data. An unprivileged user could exploit this flaw to
cause an information leak. (CVE-2012-4508)

Rodrigo Freire discovered a flaw in the Linux kernel's TCP illinois
congestion control algorithm. A local attacker could use this to cause a
denial of service. (CVE-2012-4565)

Mathias Krause discovered a flaw in the Linux kernel's XFRM netlink
interface. A local user with the NET_ADMIN capability could exploit this
flaw to leak the contents of kernel memory. (CVE-2012-6536)

Mathias Krause discovered several errors in the Linux kernel's xfrm_user
implementation. A local attacker could exploit these flaws to examine parts
of kernel memory. (CVE-2012-6537)

Mathias Krause discovered an information leak in the Linux kernel's
xfrm_user copy_to_user_auth function. A local user could exploit this flaw
to examine parts of kernel heap memory. (CVE-2012-6538)

Dave Jones discovered that the Linux kernel's socket subsystem does not
correctly ensure the keepalive action is associated with a stream socket. A
local user could exploit this flaw to cause a denial of service (system
crash) by creating a raw socket. (CVE-2012-6657)

A flaw was discovered in the Linux kernels handling of memory ranges with
PROT_NONE when transparent hugepages are in use. An unprivileged local user
could exploit this flaw to cause a denial of service (crash the system).
(CVE-2013-0309)

Mathias Krause discovered a flaw in xfrm_user in the Linux kernel. A local
attacker with NET_ADMIN capability could potentially exploit this flaw to
escalate privileges. (CVE-2013-1826)

An information leak was discovered in the Linux kernel's /dev/dvb device. A
local user could exploit this flaw to obtain sensitive information from the
kernel's stack memory. (CVE-2013-1928)

Update instructions

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

Ubuntu 12.04

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.