handouts/ho04.tex
author Christian Urban <christian dot urban at kcl dot ac dot uk>
Sat, 18 Oct 2014 02:17:21 +0100
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\documentclass{article}
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\usepackage{../style}
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\usepackage{../langs}
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\usetikzlibrary{patterns,decorations.pathreplacing}
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\begin{document}
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\section*{Handout 4 (Unix-Style Access Control)}
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Access control is essentially about deciding whether to grant
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access to a resource or deny it. This sounds easy. Right? Well
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it turns out that things are not as simple as seem at first.
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Let us study as a case how access is organised in Unix-like
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systems (Windows systems have generally similar access
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control, although the details might be quite different).
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Following the Unix-philosophy that everything is considered as
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a file, even memory or ports, access control is organised
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around 11 Bits that specify how a file can be accessed. There
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are three modes for access \textbf{r}ead, \textbf{w}rite and
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e\textbf{x}ecute. Moreover there are .... owner, group and
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everybody else.
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\end{document}
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%%% Local Variables: 
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%%% mode: latex
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%%% TeX-master: t
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%%% End: