Interesting reading on exec* access checks.

[Yuichi Nakamura]

Daniel J Walsh wrote:
> http://people.redhat.com/drepper/selinux-mem.html
I have basic question about these permissions.
Fedora Core already have "Exec Shield" to prevent execution of malicious code on memory.
I can not understand relationship between exec shield and these permissions.
What is good point of these permissions?
In other words, 
I would like to know 
"Attack that can not be prevented  by exec shield, 
 but can be prevented by these permissions(exec* permissions)".

Does anyone know ?

Yuichi Nakamura