Re: Taroon-list Digest, Vol 14, Issue 25

[Stephen Gardner <stephen-rhel uk org>]

On Mon, 18 Apr 2005, Sam Lalonde wrote:

> What does it mean to boot with "noexec=off"?
>
> I assume this means I should change grub.conf to include the following line:
>
> kernel /vmlinuz-2.6.9-5.0.3.ELsmp ro root=/dev/VolGroup00/LogVol00 rhgb quiet 
> noexec=off
>
> What are the other consequences of doing this?
>
> sam

Sam,
    The basic answer is that noexec=off disables the processor level No 
eXecute function and the Red Hat non-executable stack buffer overflow 
protection. The detailed answer is available in Arjan van de Ven's Exec 
Shield paper at

http://people.redhat.com/mingo/exec-shield/docs/WHP0006US_Execshield.pdf

    You should only need to boot with this option once, perform the grub 
install and then reboot again having unset it.

Regards,
   Stephen

References:

Fedora Rawhide grub package changelog

* Tue Feb 08 2005 Peter Jones <pjones redhat com> 0.95-8

- Mark the simulation stack executable

[ this version of grub is not shipped in RHEL4-U0 or U1 ]