USN-2908-4: Linux kernel regression
26 February 2016
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 15.10
USN-2908-1 introduced a regression in the Linux kernel.
- linux - Linux kernel
USN-2908-1 fixed vulnerabilities in the Linux kernel for Ubuntu 15.10. An incorrect locking fix caused a regression that broke graphics displays for Ubuntu 15.10 guests running within VMWare virtual machines. This update fixes the problem.
We apologize for the inconvenience.
Original advisory 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)
The problem can be corrected by updating your system to the following package versions:
- Ubuntu 15.10
- linux-image-4.2.0-30-generic - 4.2.0-30.36
- linux-image-4.2.0-30-generic-lpae - 4.2.0-30.36
- linux-image-4.2.0-30-lowlatency - 4.2.0-30.36
- linux-image-4.2.0-30-powerpc-e500mc - 4.2.0-30.36
- linux-image-4.2.0-30-powerpc-smp - 4.2.0-30.36
- linux-image-4.2.0-30-powerpc64-emb - 4.2.0-30.36
- linux-image-4.2.0-30-powerpc64-smp - 4.2.0-30.36
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.