USN-2887-2: Linux kernel (Trusty HWE) vulnerabilities

Ubuntu Security Notice USN-2887-2

1st February, 2016

linux-lts-trusty 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-trusty - Linux hardware enablement kernel from Trusty

Details

It was discovered that a use-after-free vulnerability existed in the
AF_UNIX implementation in the Linux kernel. A local attacker could use
crafted epoll_ctl calls to cause a denial of service (system crash) or
expose sensitive information. (CVE-2013-7446)

It was discovered that the KVM implementation in the Linux kernel did not
properly restore the values of the Programmable Interrupt Timer (PIT). A
user-assisted attacker in a KVM guest could cause a denial of service in
the host (system crash). (CVE-2015-7513)

Sasha Levin discovered that the Reliable Datagram Sockets (RDS)
implementation in the Linux kernel had a race condition when checking
whether a socket was bound or not. A local attacker could use this to cause
a denial of service (system crash). (CVE-2015-7990)

It was discovered that the Btrfs implementation in the Linux kernel
incorrectly handled compressed inline extants on truncation. A local
attacker could use this to expose sensitive information. (CVE-2015-8374)

Update instructions

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

Ubuntu 12.04 LTS:

linux-image-3.13.0-77-generic 3.13.0-77.121~precise1

linux-image-3.13.0-77-generic-lpae 3.13.0-77.121~precise1

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References

CVE-2013-7446, CVE-2015-7513, CVE-2015-7990, CVE-2015-8374