USN-3005-1: Linux kernel (Xenial HWE) vulnerabilities

10 June 2016

linux-lts-xenial vulnerabilities

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

  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

Justin Yackoski discovered that the Atheros L2 Ethernet Driver in the Linux kernel incorrectly enables scatter/gather I/O. A remote attacker could use this to obtain potentially sensitive information from kernel memory. (CVE-2016-2117)

Jann Horn discovered that eCryptfs improperly attempted to use the mmap() handler of a lower filesystem that did not implement one, causing a recursive page fault to occur. A local unprivileged attacker could use to cause a denial of service (system crash) or possibly execute arbitrary code with administrative privileges. (CVE-2016-1583)

Multiple race conditions where discovered in the Linux kernel’s ext4 file system. A local user could exploit this flaw to cause a denial of service (disk corruption) by writing to a page that is associated with a different users file after unsynchronized hole punching and page-fault handling. (CVE-2015-8839)

Ralf Spenneberg discovered that the Linux kernel’s GTCO digitizer USB device driver did not properly validate endpoint descriptors. An attacker with physical access could use this to cause a denial of service (system crash). (CVE-2016-2187)

Vitaly Kuznetsov discovered that the Linux kernel did not properly suppress hugetlbfs support in X86 paravirtualized guests. An attacker in the guest OS could cause a denial of service (guest system crash). (CVE-2016-3961)

Kangjie Lu discovered an information leak in the ANSI/IEEE 802.2 LLC type 2 Support implementations in the Linux kernel. A local attacker could use this to obtain potentially sensitive information from kernel memory. (CVE-2016-4485)

Kangjie Lu discovered an information leak in the routing netlink socket interface (rtnetlink) implementation in the Linux kernel. A local attacker could use this to obtain potentially sensitive information from kernel memory. (CVE-2016-4486)

Jann Horn discovered that the extended Berkeley Packet Filter (eBPF) implementation in the Linux kernel could overflow reference counters on systems with more than 32GB of physical ram and with RLIMIT_MEMLOCK set to infinite. A local unprivileged attacker could use to create a use-after- free situation, causing a denial of service (system crash) or possibly gain administrative privileges. (CVE-2016-4558)

Jann Horn discovered that the InfiniBand interfaces within the Linux kernel could be coerced into overwriting kernel memory. A local unprivileged attacker could use this to possibly gain administrative privileges on systems where InifiniBand related kernel modules are loaded. (CVE-2016-4565)

It was discovered that in some situations the Linux kernel did not handle propagated mounts correctly. A local unprivileged attacker could use this to cause a denial of service (system crash). (CVE-2016-4581)

Update instructions

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

Ubuntu 14.04 LTS
linux-image-4.4.0-24-generic - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-generic-lpae - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-lowlatency - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-powerpc-e500mc - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-powerpc-smp - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-powerpc64-emb - 4.4.0-24.43~14.04.1
linux-image-4.4.0-24-powerpc64-smp - 4.4.0-24.43~14.04.1

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