Re: exec and EXECSERVERS

[Thomas Bushnell, BSG]

"Alfred M. Szmidt" <ams@kemisten.nu> writes:

>    > What was the reason for disabling EXECSERVERS in exec?  I think that
>    > it is quite an useful feature when debugging exec, or playing around
>    > with new features for it.
> 
>    This[1] thread might interest you.
> 
>    [1] http://mail.gnu.org/pipermail/bug-hurd/2000-May/001211.html
> 
> Interesting.  Roland and/or Thomas, could you comment on the possible
> security risks, if any such existed with EXECSERVERS?

Well, a setuid exec itself should disable EXECSERVERS.  But the
environment variable might still get inherited, and seven layers of
fork/exec later, do something nasty.  So that means that setuid exec
should in fact clear EXECSERVERS in the passed environment.

That's a nasty wart, however, having the *exec server* go mucking
around with environment variables.