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<title>PShell - Psypete's Shell</title>
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<h1><center>PShell - Psypete's Shell</center></h1>
<p><font face="Arial" size="2">The PShell is a menu-driven and secured shell for use with SSH on a linux/UNIX-derivative operating system. Its menu design was taken from another popular menu-driven shell, loginshell.pl. Although it may appear similar, much code has been added and removed, and with the help of a chroot environment it has become powerfully secured. All in Perl, of
course, and liscenced under the GNU GPL. The original developer of the
loginshell program had no such liscence (even though his website differs), which is why i didnt
modify much of his existing code where i could. He is Jason Woodward (woodwardj@jaos.org)
and his website is http://opensource.jaos.org/ so dont say i never gave
credit }:></font></p>
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<h2><a href="howto.htm">How To Use PShell</a></h2><br>
<h2><a href="chroot.htm">How To Make And Use A Chroot Environment</a></h2>
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<p>Without even access to a real shell like the Bourne Again SHell, it can control access to files,
log-in an individual, and allow them access to only a few restricted programs. Optionally,
internally-handled perl functions can take the place of some of these applications, reducing
overhead of opening a new program and speeding up general access time. Plus the fact that it is
tailored to specific requirements of that command. </p>
<p><font face="Arial">So, how does it work? First one would need to create a chrooted environment
to secure file and system access. If you do not know what chroot means, please look it up. You
may create the chroot "jail" with an additional program which comes with the PShell called
"makechroot.sh". It will copy essential files from your main /usr/, /var/, /etc/, and other
folders and put it into a directory of your choice. I used an NFS-mounted directory so that
another computer holds all my chrooted data. With extra programs that i added and a full linux
installation, my whole chroot directory takes up about 270 megabytes (you only need one of these,
and with the explosion of harddrives today that isnt alot). <br>
<br> Now you need to set up the PShell shell settings in your password file. When you create a new
user, an option is to tell it what shell to use. For users of the PShell, you would give the
shell as the path to the PSell program. If your users already exist, you may edit your password
file (usually /etc/passwd) and change their current shells to the file location of the PSHell.
<br><br> Once this is done, you may simply execute sshd with the command "chroot
/path/to/chroot/directory sshd" (as long as sshd is not running). This will start up ssh in your
chroot environment. Now as soon as they SSH into that computer, they should immediately be given
the PShell menu-driven program. From here they may use the basic commands
given to them. You may easily add or remove commands in the menu if you have
a basic understanding of Perl, the programming language used. Future
releases will have a configuration-file type editing which is easy on
standard users and developers alike.
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<p>REQUIREMENTS:<br>
First and foremost, you need the Curses and Curses::Widgets modules to be
able to actually run the pshell. Secondly, you need most basic linux
utilities and they should be in their standard path (tested with Slackware
Linux 8.0). If you dont think the programs are in their path, go through the
code and simply find the program and put in the direct path. If you do not
put in the direct path, you are not assured that the pshell will be able to
execute it properly (if you got rid of /bin/sh and stuff). Then there's the
web space; the default user home directory for their web space in Apache is
"htaccess". I changed this to "www" in the script, and it's quite easy to
change it in Apache as well. Open up your apache configuration file
(httpd.conf usually) and find the line that configues mod_userdir.c. Edit
the line that says "UserDir htdocs" and replace "htdocs" with "www" and
restart Apache (usually by apachectl restart). And that's about it.
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