USN-2908-1: Linux kernel vulnerabilities

22 February 2016

linux vulnerabilities

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

  • Ubuntu 15.10

Summary

Several security issues were fixed in the kernel.

Software Description

  • linux - Linux kernel

Details

halfdog discovered that OverlayFS, when mounting on top of a FUSE mount, incorrectly propagated file attributes, including setuid. A local unprivileged attacker could use this to gain privileges. (CVE-2016-1576)

halfdog discovered that OverlayFS in the Linux kernel incorrectly propagated security sensitive extended attributes, such as POSIX ACLs. A local unprivileged attacker could use this to gain privileges. (CVE-2016-1575)

It was discovered that the Linux kernel did not properly enforce rlimits for file descriptors sent over UNIX domain sockets. A local attacker could use this to cause a denial of service. (CVE-2013-4312)

It was discovered that the Linux kernel’s Filesystem in Userspace (FUSE) implementation did not handle initial zero length segments properly. A local attacker could use this to cause a denial of service (unkillable task). (CVE-2015-8785)

Andy Lutomirski discovered a race condition in the Linux kernel’s translation lookaside buffer (TLB) handling of flush events. A local attacker could use this to cause a denial of service or possibly leak sensitive information. (CVE-2016-2069)

Update instructions

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

Ubuntu 15.10
linux-image-4.2.0-30-generic - 4.2.0-30.35
linux-image-4.2.0-30-generic-lpae - 4.2.0-30.35
linux-image-4.2.0-30-lowlatency - 4.2.0-30.35
linux-image-4.2.0-30-powerpc-e500mc - 4.2.0-30.35
linux-image-4.2.0-30-powerpc-smp - 4.2.0-30.35
linux-image-4.2.0-30-powerpc64-emb - 4.2.0-30.35
linux-image-4.2.0-30-powerpc64-smp - 4.2.0-30.35

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