1 files changed, 207 insertions, 0 deletions
diff --git a/sag-0.6.1-www/sag-0.6.1.html/x1991.html b/sag-0.6.1-www/sag-0.6.1.html/x1991.html
new file mode 100644
index 0000000..b8184e9
--- /dev/null
+++ b/sag-0.6.1-www/sag-0.6.1.html/x1991.html
@@ -0,0 +1,207 @@
+<!DOCTYPE HTML PUBLIC "-//Norman Walsh//DTD DocBook HTML 1.0//EN">
+<HTML
+><HEAD
+><TITLE
+>Access control</TITLE
+><META
+NAME="GENERATOR"
+CONTENT="Modular DocBook HTML Stylesheet"><LINK
+REL="HOME"
+TITLE="The Linux System Administrators' Guide"
+HREF="book1.html"><LINK
+REL="UP"
+TITLE="Logging In And Out"
+HREF="c1905.html"><LINK
+REL="PREVIOUS"
+TITLE="X and xdm"
+HREF="x1988.html"><LINK
+REL="NEXT"
+TITLE="Shell startup"
+HREF="x2008.html"></HEAD
+><BODY
+BGCOLOR="#FFFFFF"
+TEXT="#000000"
+><DIV
+CLASS="NAVHEADER"
+><TABLE
+WIDTH="100%"
+BORDER="0"
+CELLPADDING="0"
+CELLSPACING="0"
+><TR
+><TH
+COLSPAN="3"
+ALIGN="center"
+>The Linux System Administrators' Guide</TH
+></TR
+><TR
+><TD
+WIDTH="10%"
+ALIGN="left"
+VALIGN="bottom"
+><A
+HREF="x1988.html"
+>Prev</A
+></TD
+><TD
+WIDTH="80%"
+ALIGN="center"
+VALIGN="bottom"
+>Chapter 8. Logging In And Out</TD
+><TD
+WIDTH="10%"
+ALIGN="right"
+VALIGN="bottom"
+><A
+HREF="x2008.html"
+>Next</A
+></TD
+></TR
+></TABLE
+><HR
+ALIGN="LEFT"
+WIDTH="100%"></DIV
+><DIV
+CLASS="SECT1"
+><H1
+CLASS="SECT1"
+><A
+NAME="AEN1991"
+>Access control</A
+></H1
+><P
+> The user database is traditionally contained in the
+	<TT
+CLASS="FILENAME"
+>/etc/passwd</TT
+> file.	Some systems use
+	<I
+CLASS="GLOSSTERM"
+>shadow passwords</I
+>, and have moved the
+	passwords to <B
+CLASS="COMMAND"
+>/etc/shadow</B
+>.  Sites with many
+	computers that share the accounts use NIS or some other method
+	to store the user database; they might also automatically copy
+	the database from one central location to all other computers.
+	</P
+><P
+> The user database contains not only the passwords, but
+	also some additional information about the users, such as their
+	real names, home directories, and login shells.  This other
+	information needs to be public, so that anyone can read it.
+	Therefore the password is stored encrypted.  This does have
+	the drawback that anyone with access to the encrypted password
+	can use various cryptographical methods to guess it, without
+	trying to actually log into the computer.  Shadow passwords try
+	to avoid this by moving the password into another file, which
+	only root can read (the password is still stored encrypted).
+	However, installing shadow passwords later onto a system that
+	did not support them can be difficult.	</P
+><P
+> With or without passwords, it is important to make
+	sure that all passwords in a system are good, i.e., not easily
+	guessable.  The <B
+CLASS="COMMAND"
+>crack</B
+> program can be used
+	to crack passwords; any password it can find is by definition
+	not a good one.  While <B
+CLASS="COMMAND"
+>crack</B
+> can be run
+	by intruders, it can also be run by the system adminstrator
+	to avoid bad passwords.  Good passwords can also be enforced
+	by the <B
+CLASS="COMMAND"
+>passwd</B
+> program; this is in fact more
+	effective in CPU cycles, since cracking passwords requires quite
+	a lot of computation.  </P
+><P
+> The user group database is kept in
+	<TT
+CLASS="FILENAME"
+>/etc/group</TT
+>; for systems with shadow
+	passwords, there can be a <TT
+CLASS="FILENAME"
+>/etc/shadow.group</TT
+>.
+	</P
+><P
+> root usually can't login via most terminals
+	or the network, only via terminals listed in the
+	<TT
+CLASS="FILENAME"
+>/etc/securetty</TT
+> file.  This makes it necessary
+	to get physical access to one of these terminals.  It is, however,
+	possible to log in via any terminal as any other user, and use
+	the <B
+CLASS="COMMAND"
+>su</B
+> command to become root.  </P
+></DIV
+><DIV
+CLASS="NAVFOOTER"
+><HR
+ALIGN="LEFT"
+WIDTH="100%"><TABLE
+WIDTH="100%"
+BORDER="0"
+CELLPADDING="0"
+CELLSPACING="0"
+><TR
+><TD
+WIDTH="33%"
+ALIGN="left"
+VALIGN="top"
+><A
+HREF="x1988.html"
+>Prev</A
+></TD
+><TD
+WIDTH="34%"
+ALIGN="center"
+VALIGN="top"
+><A
+HREF="book1.html"
+>Home</A
+></TD
+><TD
+WIDTH="33%"
+ALIGN="right"
+VALIGN="top"
+><A
+HREF="x2008.html"
+>Next</A
+></TD
+></TR
+><TR
+><TD
+WIDTH="33%"
+ALIGN="left"
+VALIGN="top"
+>X and xdm</TD
+><TD
+WIDTH="34%"
+ALIGN="center"
+VALIGN="top"
+><A
+HREF="c1905.html"
+>Up</A
+></TD
+><TD
+WIDTH="33%"
+ALIGN="right"
+VALIGN="top"
+>Shell startup</TD
+></TR
+></TABLE
+></DIV
+></BODY
+></HTML
+>
+\ No newline at end of file