USN-3169-2: Linux kernel (Xenial HWE) vulnerabilities
11 January 2017
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 14.04 LTS
Several security issues were fixed in the kernel.
- linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty
USN-3169-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu 14.04 LTS.
Dmitry Vyukov discovered that the KVM implementation in the Linux kernel did not properly initialize the Code Segment (CS) in certain error cases. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2016-9756)
Andrey Konovalov discovered that signed integer overflows existed in the setsockopt() system call when handling the SO_SNDBUFFORCE and SO_RCVBUFFORCE options. A local attacker with the CAP_NET_ADMIN capability could use this to cause a denial of service (system crash or memory corruption). (CVE-2016-9793)
Baozeng Ding discovered a race condition that could lead to a use-after- free in the Advanced Linux Sound Architecture (ALSA) subsystem of the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2016-9794)
The problem can be corrected by updating your system to the following package versions:
- Ubuntu 14.04 LTS
- linux-image-4.4.0-59-generic - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-generic-lpae - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-lowlatency - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-powerpc-e500mc - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-powerpc-smp - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-powerpc64-emb - 4.4.0-59.80~14.04.1
- linux-image-4.4.0-59-powerpc64-smp - 4.4.0-59.80~14.04.1
- linux-image-generic-lpae-lts-xenial - 22.214.171.124.46
- linux-image-generic-lts-xenial - 126.96.36.199.46
- linux-image-lowlatency-lts-xenial - 188.8.131.52.46
- linux-image-powerpc-e500mc-lts-xenial - 184.108.40.206.46
- linux-image-powerpc-smp-lts-xenial - 220.127.116.11.46
- linux-image-powerpc64-emb-lts-xenial - 18.104.22.168.46
- linux-image-powerpc64-smp-lts-xenial - 22.214.171.124.46
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.