[techtalk] Hi.I'm new.Postfix/mail server questions...

[Penguina]

On Tue, 22 May 2001, Mary Gardiner wrote:

> On Tue, May 22, 2001 at 07:14:38AM +1000, jenn at simegen.com wrote:
> > > It seems a pretty
> > > straitforward thing to ask...no shell access, but I'm finding it
> > > extrememly difficult to find good documentation on it.
> >
> > Set their 'shell' to /bin/false or /bin/true. Either will block them
> > from having a shell, yet give them a username and password.
>
> Or bin/myshell, where myshell is a script that echoes
> "You do not have access to shell account on this box."
>
> Mary.

Yikes!  A script that echos?  How can you be absolutely sure
it runs as the correct user and group, and always exits
in exactly the same way, always returning the same value
(even if the user repeatedly types ctrl-C's and such at
the 'null' shell script).  How can you be sure you're
invoking a shell who's "echo" has no known buffer overflow?

cheers