U radu jezgre operacijskog sustava Ubuntu 11.04 uočene su višestruke sigurnosne ranjivosti koje napadaču omogućuju izvođenje DoS napada, stjecanje povećanih ovlasti, otkrivanje osjetljivih informacija i pokretanje proizvoljnog programskog koda.

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Ubuntu Security Notice USN-1246-1
October 25, 2011

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

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

- Ubuntu 11.04

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

Dan Rosenberg discovered that the IPv4 diagnostic routines did not
correctly validate certain requests. A local attacker could exploit this to
consume CPU resources, leading to a denial of service. (CVE-2011-2213)

Dan Rosenberg discovered that the Bluetooth stack incorrectly handled
certain L2CAP requests. If a system was using Bluetooth, a remote attacker
could send specially crafted traffic to crash the system or gain root
privileges. (CVE-2011-2497)

It was discovered that the EXT4 filesystem contained multiple off-by-one
flaws. A local attacker could exploit this to crash the system, leading to
a denial of service. (CVE-2011-2695)

Mauro Carvalho Chehab discovered that the si4713 radio driver did not
correctly check the length of memory copies. If this hardware was
available, a local attacker could exploit this to crash the system or gain
root privileges. (CVE-2011-2700)

Herbert Xu discovered that certain fields were incorrectly handled when
Generic Receive Offload (CVE-2011-2723)

Time Warns discovered that long symlinks were incorrectly handled on Be
filesystems. A local attacker could exploit this with a malformed Be
filesystem and crash the system, leading to a denial of service.
(CVE-2011-2928)

Dan Kaminsky discovered that the kernel incorrectly handled random sequence
number generation. An attacker could use this flaw to possibly predict
sequence numbers and inject packets. (CVE-2011-3188)

Darren Lavender discovered that the CIFS client incorrectly handled certain
large values. A remote attacker with a malicious server could exploit this
to crash the system or possibly execute arbitrary code as the root user.
(CVE-2011-3191)

Update instructions:

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

Ubuntu 11.04:
  linux-image-2.6.38-12-generic   2.6.38-12.51
  linux-image-2.6.38-12-generic-pae  2.6.38-12.51
  linux-image-2.6.38-12-omap      2.6.38-12.51
  linux-image-2.6.38-12-powerpc   2.6.38-12.51
  linux-image-2.6.38-12-powerpc-smp  2.6.38-12.51
  linux-image-2.6.38-12-powerpc64-smp  2.6.38-12.51
  linux-image-2.6.38-12-server    2.6.38-12.51
  linux-image-2.6.38-12-versatile  2.6.38-12.51
  linux-image-2.6.38-12-virtual   2.6.38-12.51

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-1246-1
  CVE-2011-2213, CVE-2011-2497, CVE-2011-2695, CVE-2011-2700,
  CVE-2011-2723, CVE-2011-2928, CVE-2011-3188, CVE-2011-3191

Package Information:
  https://launchpad.net/ubuntu/+source/linux/2.6.38-12.51