\begin{exe} {setuid}

   \begin{enumerate}
      \item
      As root, copy \filelink{/bin/ls} over to the current
      directory.
      \item
      As a normal user, attempt to get a directory listing of
      the \filelink{/root} directory using the local copy of
      \textbf{ls}. This should fail.
      \item
      As root, use the \textbf{chmod} command to set the
      setuid bit on \filelink{./ls}.
      \item
      As a normal user, attempt to get a listing of
      \filelink{/root} again.  It should work this time.
   \end{enumerate}

   \begin{sol}

      \begin{enumerate}
         \item
         \begin{cmd}
$ sudo cp /bin/ls .
         \end{cmd}
         \item
         \begin{cmd}
$ ./ls /root
         \end{cmd}
         \item
         \begin{cmd}
$ sudo chmod +s ./ls
         \end{cmd}
         \item
         \begin{cmd}
./ls /root
         \end{cmd}
      \end{enumerate}
   \end{sol}
\end{exe}

