The overlayfs implementation in the linux (aka Linux kernel) package before
3.19.0-21.21 in Ubuntu through 15.04 does not properly check permissions
for file creation in the upper filesystem directory, which allows local
users to obtain root access by leveraging a configuration in which
overlayfs is permitted in an arbitrary mount namespace.

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.

tyhicks	This CVE is specific to Ubuntu since Ubuntu allows overlayfs mounts inside of user namespaces
jdstrand	android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support