USN-2643-2: Linux kernel regression

Releases

• Ubuntu 14.04 ESM

Packages

• linux - Linux kernel

Details

The Fix for CVE-2015-1328 introduced a regression into the Linux kernel's
overlayfs file system. The removal of a directory that only exists on the
lower layer results in a kernel panic.

We apologize for the inconvenience.

Original advisory details:

Philip Pettersson discovered a privilege escalation when using overlayfs
mounts inside of user namespaces. A local user could exploit this flaw to
gain administrative privileges on the system.

Update instructions

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

Ubuntu 14.04

• linux-image-3.13.0-55-generic - 3.13.0-55.94
• linux-image-3.13.0-55-generic-lpae - 3.13.0-55.94
• linux-image-3.13.0-55-lowlatency - 3.13.0-55.94
• linux-image-3.13.0-55-powerpc-e500 - 3.13.0-55.94
• linux-image-3.13.0-55-powerpc-e500mc - 3.13.0-55.94
• linux-image-3.13.0-55-powerpc-smp - 3.13.0-55.94
• linux-image-3.13.0-55-powerpc64-emb - 3.13.0-55.94
• linux-image-3.13.0-55-powerpc64-smp - 3.13.0-55.94

After a standard system update you need to reboot your computer to make
all the necessary changes.

References

• http://bugs.launchpad.net/bugs/1465998