Is there Exec Shield buffer overflow protection for Ubuntu?

Is there Exec Shield buffer overflow protection for Ubuntu?

I tried to enable Exec Shield on Ubuntu 12.04 with the following command

sudo sysctl -w kernel.exec-shield=1

but it said

error: "kernel.exec-shield" is an unknown key

If not, what is the equivalent solution for Ubuntu and how can I install and enable it?

Ubuntu has NX protection enabled by default. This either uses hardware NX when the CPU supports it, or uses NX emulation in the kernel (the equivalent of the Red Hat Exec Shield patch).

For more information, visit: https://wiki.ubuntu.com/Security/Features

more specifically: https://wiki.ubuntu.com/Security/Features#nx