=========================================================================Ubuntu Security Notice USN-2759-1
October 01, 2015

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:

It was discovered that an integer overflow error existed in the SCSI
generic (sg) driver in the Linux kernel. A local attacker with write
permission to a SCSI generic device could use this to cause a denial of
service (system crash) or potentially escalate their privileges.
(CVE-2015-5707)

Marc-André Lureau discovered that the vhost driver did not properly
release the userspace provided log file descriptor. A privileged attacker
could use this to cause a denial of service (resource exhaustion).
(CVE-2015-6252)

It was discovered that the Linux kernel's perf subsystem did not bound
callchain backtraces on PowerPC 64. A local attacker could use this to
cause a denial of service. (CVE-2015-6526)

Update instructions:

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

Ubuntu 12.04 LTS:
  linux-image-3.2.0-91-generic    3.2.0-91.129
  linux-image-3.2.0-91-generic-pae  3.2.0-91.129
  linux-image-3.2.0-91-highbank   3.2.0-91.129
  linux-image-3.2.0-91-omap       3.2.0-91.129
  linux-image-3.2.0-91-powerpc-smp  3.2.0-91.129
  linux-image-3.2.0-91-powerpc64-smp  3.2.0-91.129
  linux-image-3.2.0-91-virtual    3.2.0-91.129

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-2759-1
  CVE-2015-5707, CVE-2015-6252, CVE-2015-6526

Package Information:
  https://launchpad.net/ubuntu/+source/linux/3.2.0-91.129