root / pykota / trunk / SECURITY @ 2069

# $Id$

PyKota - Print Quota for CUPS and LPRng

(c) 2003, 2004, 2005 Jerome Alet <alet@librelogiciel.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

====================================================================

How to improve PyKota's security :
----------------------------------

  - Secure your printers :  
  
    Tell them to refuse any print job not coming from your print server. 
    Do this with telnet to set ACLs based on incoming IP addresses if 
    possible, or through any other way. 
        
    Put all your printers on a private unroutable subnet, different from 
    the subnet on which your client hosts will reside. Ensure that the 
    only machine allowed to access to this subnet is your print server. 
    
    
  - Secure your print servers :  
  
    Don't give shell access to your users on your print servers, and 
    don't let them execute unauthorized commands : they could very well 
    compile and/or execute tools like NetCat, and send datas directly to 
    the printer in the case the printer is networked, thus bypassing the 
    printing system and PyKota. 
        
    Ensure that no regular user can read PyKota administrator's 
    configuration file, but that both the PyKota Administrator and the 
    user the printing system is run as can read it. With CUPS under 
    Debian you may want to do : 
    
        $ chown pykota.pykota pykota.conf pykotadmin.conf    
        $ chmod 640 pykota.conf
        $ chmod 600 pykotadmin.conf
        
    Depending on your needs, you may want to put the user the printing 
    system is run as in the group 'pykota', and relax permissions a bit 
    so that this user can read the pykotadmin.conf file while printing. 
    For example : 
    
        $ chmod 640 pykotadmin.conf
        $ adduser lp pykota
          (this makes user 'lp' a member of group 'pykota')
    
    Letting any user read PyKota administrator's configuration file may 
    expose passwords or database information which would allow write 
    access to the database, and so may transform your print quota 
    management in a nightmare. 
  
    If you want to let users generate their own print quota reports, 
    then ensure that /etc/pykota/pykota.conf is readable by these users. 
    To do this you can either put this users in the group 'pykota' while 
    ensuring they can't read pykotadmin.conf with 'chmod 600 pykotadmin.conf'
    or simply allow everyone to read pykota.conf with 'chmod 644 pykota.conf'
      
  - Secure your CGI scripts :    
  
    If you use printquota.cgi or dumpykota.cgi, ensure that the user 
    they are run as can read the pykota.conf file but NOT the 
    pykotadmin.conf file. 
        
    The particular user they will be run as depends on your web server's 
    settings. 
        
    If you want to further restrict the access to these CGI scripts, 
    please read your web server's documentation to add either 
    encryption, authentication or both. 
        
    The CGI scripts will honor the content of the REMOTE_USER CGI 
    environment variable which is set by your web server if an 
    authentication took place. If REMOTE_USER contains 'root' then, even 
    if you didn't authenticate using the real root account and password, 
    the scripts will consider they have been run by a PyKota 
    administrator and will report all datas if asked to do so. If 
    REMOTE_USER is not present, which means that you didn't chose to 
    secure access to your CGI scripts, the same will happen. If 
    REMOTE_USER contains something else, only datas pertaining to this 
    user will be made available through the web. 
    
    NB : In any case, the CGI scripts actually included in PyKota only
    do readonly accesses to PyKota's database.
    
  - Secure your database connection :
  
    Depending on the database backend used, either PostgreSQL or
    OpenLDAP, you may have to take additionnal measures to render
    your database more secure. Please refer to your database system's
    documentation on configuration to learn how to do so. This is out
    of the scope of the present document which will only give basic
    informations.
    
    Keep in mind that if you use a centralized database, you may have
    to restrict which hosts can access to it (i.e. the Print Servers).
    
    For the PostgreSQL backend, PyKota already defines a user with 
    read/write access and another user with read-only access to
    the Print Quota Database. PyKota doesn't set any passwords
    for these users though, but doing it is recommended, and 
    explained elsewhere in PyKota's documentation.
    
    For the LDAP backend, you have to ensure that no regular
    user can write to any PyKota specific attribute or objectClass.
    Otherwise they could modify their quota at will.
    
    You also have to define two binding DNs in your LDAP tree,
    one of them should be able to have a read only access to
    everything. The other one should be able to write, for 
    example your LDAP admin user is fine for this.
    Now put the readonly user in /etc/pykota/pykota.conf
    and the read-write one in /etc/pykota/pykotadmin.conf
    
====================================================================