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Re: Permissions 101



On Mon, 15 Jan 2001, Bob Bernstein wrote:

> $ ./sutest
> does this work?
> /var/log/user.log: Permission denied
> 
> Can someone explain what's going on here? Is starting a shell the problem?

The setuid bit doesn't work on shell scripts.  You will have to compile a
C program use use perl.  Perl scripts work with the setuid bit because
perl has a special setuid executable to run them with.

Essentially having shell scripts work with the setuid bit allows a
malicious user to "trick" the system into running a false interpreter with
root permissions.  This won't do, so root shell scripts are prohibited.



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