=========================================================================Ubuntu Security Notice USN-1795-1
April 08, 2013

linux-lts-quantal 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-lts-quantal: Linux hardware enablement kernel from Quantal

Details:

Andrew Jones discovered a flaw with the xen_iret function in Linux kernel's
Xen virtualizeation. In the 32-bit Xen paravirt platform an unprivileged
guest OS user could exploit this flaw to cause a denial of service (crash
the system) or gain guest OS privilege. (CVE-2013-0228)

Emese Revfy discovered that in the Linux kernel signal handlers could leak
address information across an exec, making it possible to by pass ASLR
(Address Space Layout Randomization). A local user could use this flaw to
by pass ASLR to reliably deliver an exploit payload that would otherwise be
stopped (by ASLR). (CVE-2013-0914)

A memory use after free error was discover in the Linux kernel's tmpfs
filesystem. A local user could exploit this flaw to gain privileges or
cause a denial of service (system crash). (CVE-2013-1767)

Mateusz Guzik discovered a race in the Linux kernel's keyring. A local user
could exploit this flaw to cause a denial of service (system crash).
(CVE-2013-1792)

Mathias Krause discovered a memory leak in the Linux kernel's crypto report
API. A local user with CAP_NET_ADMIN could exploit this leak to examine
some of the kernel's stack memory. (CVE-2013-2546)

Mathias Krause discovered a memory leak in the Linux kernel's crypto report
API. A local user with CAP_NET_ADMIN could exploit this leak to examine
some of the kernel's heap memory. (CVE-2013-2547)

Mathias Krause discovered information leaks in the Linux kernel's crypto
algorithm report API. A local user could exploit these flaws to leak kernel
stack and heap memory contents. (CVE-2013-2548)

Update instructions:

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

Ubuntu 12.04 LTS:
  linux-image-3.5.0-27-generic    3.5.0-27.46~precise1

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:
  https://ubuntu.com/security/notices/USN-1795-1
  CVE-2013-0228, CVE-2013-0914, CVE-2013-1767, CVE-2013-1792,
  CVE-2013-2546, CVE-2013-2547, CVE-2013-2548

Package Information:
  https://launchpad.net/ubuntu/+source/linux-lts-quantal/3.5.0-27.46~precise1