From SELinux Wiki
 Installing SELinux
Starting with Hardy Heron SELinux has been integrated into Ubuntu and can be installed via apt.
- Install the selinux package:
# apt-get install selinux
- Change the SELinux mode in /etc/selinux/config (optional):
# sudo sed -i 's/SELINUX=.*/SELINUX=enforcing/' /etc/selinux/config
# sudo sed -i 's/SELINUX=.*/SELINUX=permissive/' /etc/selinux/config
During shutdown all of the files on the system will be labeled. This may take some time depending on how many files you have and disk speed.