Re: saved IDs and exec (standard violation?)

[Thomas Bushnell, BSG]

Roland McGrath <roland@frob.com> writes:

> The only drawback I see is in the case when svuid!=euid or svgid!=egid, and
> you are executing an sugid file.  The user will reauthenticate everything
> for the svuid=euid, svgid=egid change and then the filesystem will
> reauthenticate everything again to do the suid/sgid.  So, a sugid program
> that execs another sugid program directly without an intervening exec of a
> non-suid program--a pretty rare event, I would guess.

I'm happy to gunk up setuid execs with however many extra RPCs as long
as normal execs can remain speedy.

> > But there might be a security reason why we have to force the change
> > to be made.  But I can't possibly see what that would be.
> 
> I don't think any concept of security is sensical for non-sugid execs with
> EXEC_SECURE.  The user who made the call will always be able to grab the
> process by its scrawny little task port and diddle its ports out the wazoo.

Exactly my thinking.