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\begin{document}+
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\section*{Coursework for 7CCSMSEN}+
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+
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This coursework is worth 10\% and is due on 1 December at 16:00. You+
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are asked to fill in the access control matrix below giving the+
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correct access rights. You have to submit your answers at KEATS. You+
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can submit your answers in a txt-file or as pdf.+
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+
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+
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\subsubsection*{Disclaimer}+
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+
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It should be understood that the work you submit represents your+
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\textbf{own} effort! You are not supposed to work in groups and have+
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not copied any solution from anyone else.\bigskip+
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+
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+
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\subsection*{Task}+
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+
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A Unix directory might look as follows:+
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+
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\begin{center}+
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\begin{verbatim}+
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$ ls -ld . * */*+
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drwxr-xr-x 1 ping staff     32768 Apr  2 2010 .+
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-rw----r-- 1 ping students  31359 Jul 24 2011 manual.txt+
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-r--rw--w- 1 bob  students   4359 Jul 24 2011 report.txt+
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-rwsr--r-x 1 bob  students 141359 Jun  1 2013 microedit+
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dr--r-xr-x 1 bob  staff     32768 Jul 23 2011 src+
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-rw-r--r-- 1 bob  staff     81359 Feb 28 2012 src/code.c+
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-r--rw---- 1 emma students    959 Jan 23 2012 src/code.h+
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\end{verbatim}+
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\end{center}+
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+
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\noindent+
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with group memberships assigned as follows:+
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\begin{center}+
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\begin{tabular}{ll}+
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Members of group staff: & \texttt{ping}, \texttt{bob}, \texttt{emma}\\ +
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Members of group students: & \texttt{emma}\\+
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\end{tabular}+
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\end{center}+
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+
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\noindent+
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The file \texttt{microedit} is a text editor, which allows its users+
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to open, edit and save files. Note carefully that microedit has set+
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its \textbf{setuid bit}.  Fill in the access control matrix below+
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that shows for each of the above five files, whether \texttt{ping},+
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\texttt{bob}, or \texttt{emma} are able to read (R) or replace (W) its+
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contents using the editor microedit.\bigskip+
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+
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\begin{center}+
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\def\arraystretch{1.5}  +
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\begin{tabular}{r|c|c|c|c|c}+
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        & manual.txt & report.txt & microedit & src/code.c & src/code.h \\\hline+
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ping & & & & &\\\hline+
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bob & & & & &\\\hline+
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emma   & & & & &\\+
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\end{tabular}+
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\end{center}\bigskip+
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+
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\noindent+
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For help about how to fill in the access control matrix, see additional hints+
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uploaded to KEATS.+
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\end{document}+
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+
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