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Re: restricted bash (rbash)



On Tue, Nov 14, 2000 at 04:34:33PM +0100, Jan Martin Mathiassen wrote:
> On Tue, Nov 14, 2000 at 01:30:57PM -0200, Pedro Zorzenon Neto wrote:

> >   When the user logs in, rbash is being executed and the restricted login is
> > working well. But, if the user executes 'bash', everything becames unrestricted.
> > 
> >   How can I deny the execution of shells inside rbash?
> > 
> >     Thanks
> >     Pedro
> 
> My first thought would be to remove the executable flag for other users,
> make a special group for bash, and add anyone that should have access to
> bash in that group.
> 
> haven't tried it, so... take it with a grain of salt.

that won't work since rbash is just a symlink to bash.  

the real way of using restricted shell is to change the user's PATH to
something very limited say /usr/local/restricted and putting a very
limited set of symlinks in there.  its very easy to break out of a
restricted shell if you allow the user to run too much, for example,
if you let them run emacs or vi they can use built in shell escapes to
run a real shell.

-- 
Ethan Benson
http://www.alaska.net/~erbenson/

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