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105 lines
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<!Converted with LaTeX2HTML 95.1 (Fri Jan 20 1995) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds >
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<TITLE>4.1.1 The root account</TITLE>
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<BR> <HR><A NAME=tex2html3778 HREF="node158.html"><IMG ALIGN=BOTTOM ALT="next" SRC="next_motif.gif"></A> <A NAME=tex2html3776 HREF="node156.html"><IMG ALIGN=BOTTOM ALT="up" SRC="up_motif.gif"></A> <A NAME=tex2html3770 HREF="node156.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif"></A> <A NAME=tex2html3780 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <A NAME=tex2html3781 HREF="node250.html"><IMG ALIGN=BOTTOM ALT="index" SRC="index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html3779 HREF="node158.html">4.1.2 Abusing the system</A>
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<B>Up:</B> <A NAME=tex2html3777 HREF="node156.html">4.1 About RootHats, </A>
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<B> Previous:</B> <A NAME=tex2html3771 HREF="node156.html">4.1 About RootHats, </A>
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<BR> <HR> <P>
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<H2><A NAME=SECTION00611000000000000000>4.1.1 The root account</A></H2>
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<P>
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<A NAME=4173> </A>
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Ordinary users are generally
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restricted so that they can't do harm to anybody else on the
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system, just to themselves. File permissions on the system
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are arranged such that normal users aren't allowed to delete
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or modify files in directories shared by all users (such as
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<tt>/bin</tt> and <tt>/usr/bin</tt>. Most users also protect their
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own files with the appropriate file permissions so that other
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users can't access or modify those files.
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<P>
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There are no such restrictions on <tt>root</tt>. The user <tt>root</tt>
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can read, modify, or delete any file on the system, change
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permissions and ownerships on any file, and run special programs,
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such as those which partition the drive or create filesystems.
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The basic idea is that the person or persons who run and take
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care of the system logs in as <tt>root</tt> whenever it is necessary to
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perform tasks that cannot be executed as a normal user.
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Because <tt>root</tt> can do anything, it is easy
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to make mistakes that have catastrophic consequences when logged
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in using this account.
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<A NAME=4180> </A>
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<P>
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For example, as a normal user, if you inadvertently attempt to delete
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all of the files in <tt>/etc</tt>, the system will not permit you to do so.
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However, when logged in as <tt>root</tt>, the system won't complain at all.
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It is very easy to trash your system when using <tt>root</tt>. The best
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way to prevent accidents is to:
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<UL><LI> Sit on your hands before you press <IMG BORDER=0 ALIGN=BOTTOM ALT="" SRC="img238.gif"> on a command which
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may cause damage. For example, if you're about to clean out a directory,
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before hitting <IMG BORDER=0 ALIGN=BOTTOM ALT="" SRC="img239.gif">, re-read the entire command and make sure
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that it is correct.
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<P>
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<LI> Don't get accustomed to using <tt>root</tt>. The more comfortable you
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are in the role of the <tt>root</tt> user, the more likely you are to
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confuse your privileges with those of a normal user. For example, you
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might <em>think</em> that you're logged in as <tt>larry</tt>, when you're
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really logged in as <tt>root</tt>.
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<P>
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<A NAME=4192> </A>
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<LI> Use a different prompt for the <tt>root</tt> account. You should
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change <tt>root</tt>'s <tt>.bashrc</tt> or <tt>.login</tt> file to set the
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shell prompt to something other than your regular user prompt. For
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example, many people use the character ``<tt>$</tt>'' in prompts for
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regular users, and reserve the character ``<tt>#</tt>'' for the <tt>root</tt>
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user prompt.
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<P>
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<LI> Only login as <tt>root</tt> when absolutely necessary. And, as soon as
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you're finished with your work as <tt>root</tt>, log out. The less you use
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the <tt>root</tt> account, the less likely you'll be to do damage on your
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system.
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<P>
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</UL>
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Of course, there is a breed of UNIX hackers out there who use <tt>root</tt>
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for virtually everything. But every one of them has, at some point,
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made a silly mistake as <tt>root</tt> and trashed the system. The general
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rule is, until you're familiar with the lack of restrictions on <tt>root</tt>,
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and are comfortable using the system without such restrictions, login
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as <tt>root</tt> sparingly.
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<P>
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Of course, everyone makes mistakes. Linus Torvalds himself once accidentally
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deleted the entire kernel directory tree on his system. Hours of work
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were lost forever. Fortunately, however, because of his knowledge of
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the filesystem code, he was able to reboot the system and reconstruct the
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directory tree by hand on disk.
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<P>
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Put another way, if you picture using the <tt>root</tt>
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account as wearing a special magic hat that gives you lots of
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power, so that you can, by waving your hand, destroy entire
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cities, it is a good idea to be a bit careful about what you
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do with your hands. Since it is easy to move your hand in a
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destructive way by accident, it is not a good idea to wear the
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magic hat when it is not needed, despite the wonderful
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feeling.
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<A NAME=4209> </A>
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<P>
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<BR> <HR><A NAME=tex2html3778 HREF="node158.html"><IMG ALIGN=BOTTOM ALT="next" SRC="next_motif.gif"></A> <A NAME=tex2html3776 HREF="node156.html"><IMG ALIGN=BOTTOM ALT="up" SRC="up_motif.gif"></A> <A NAME=tex2html3770 HREF="node156.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="previous_motif.gif"></A> <A NAME=tex2html3780 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <A NAME=tex2html3781 HREF="node250.html"><IMG ALIGN=BOTTOM ALT="index" SRC="index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html3779 HREF="node158.html">4.1.2 Abusing the system</A>
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<B>Up:</B> <A NAME=tex2html3777 HREF="node156.html">4.1 About RootHats, </A>
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<B> Previous:</B> <A NAME=tex2html3771 HREF="node156.html">4.1 About RootHats, </A>
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<BR> <HR> <P>
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<BR> <HR>
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<P><ADDRESS>
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<I>Matt Welsh <BR>
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mdw@sunsite.unc.edu</I>
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