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Work on encrypted URLs

    1: # The LearningOnline Network
    2: # URL translation for encrypted filenames
    3: #
    4: # $Id: lonenc.pm,v 1.1 2004/03/31 04:38:06 www Exp $
    5: #
    6: # Copyright Michigan State University Board of Trustees
    7: #
    8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
    9: #
   10: # LON-CAPA is free software; you can redistribute it and/or modify
   11: # it under the terms of the GNU General Public License as published by
   12: # the Free Software Foundation; either version 2 of the License, or
   13: # (at your option) any later version.
   14: #
   15: # LON-CAPA is distributed in the hope that it will be useful,
   16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   18: # GNU General Public License for more details.
   19: #
   20: # You should have received a copy of the GNU General Public License
   21: # along with LON-CAPA; if not, write to the Free Software
   22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   23: #
   24: # /home/httpd/html/adm/gpl.txt
   25: #
   26: # http://www.lon-capa.org/
   27: #
   28: 
   29: package Apache::lonenc;
   30: 
   31: use strict;
   32: use Apache::Constants qw(:common :remotehost);
   33: use Apache::lonnet();
   34: use Apache::File();
   35: use Apache::loncommon;
   36: use Crypt::IDEA;
   37: 
   38: sub handler {
   39:     my $r = shift;
   40:     my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
   41:     my $lonid=$cookies{'lonID'};
   42:     my $cookie;
   43:     if ($lonid) {
   44: 	my $handle=$lonid->value;
   45:         $handle=~s/\W//g;
   46:         my $lonidsdir=$r->dir_config('lonIDsDir');
   47:         if ((-e "$lonidsdir/$handle.id") && ($handle ne '')) {
   48: # Initialize Environment
   49:             &Apache::lonnet::transfer_profile_to_env($lonidsdir,$handle);
   50: # Decrypt URL and redirect
   51: 	    $r->internal_redirect(&unencrypted($r->uri));
   52: 	    return OK;
   53: 	} 
   54:     }
   55:     return FORBIDDEN;
   56: }
   57: 
   58: sub unencrypted {
   59:     my $uri=shift;
   60:     $uri=~s/^\/enc\/(\d+)\///;
   61:     &Apache::lonnet::logthis($uri);
   62:     my $cmdlength=$1;
   63:     unless ($ENV{'course.'.$ENV{'request.course.id'}.'.internal.encseed'}) {
   64: 	return '/'.$uri;
   65:     }
   66:     $uri=&Apache::lonnet::unescape($uri);
   67:     my $cipher=
   68: 	new IDEA $ENV{'course.'.$ENV{'request.course.id'}.'.internal.encseed'};
   69:     &Apache::lonnet::logthis($ENV{'course.'.$ENV{'request.course.id'}.'.internal.encseed'});
   70:     my $decuri='';
   71:     for (my $encidx=0;$encidx<length($uri);$encidx+=16) {
   72: 	$decuri.=$cipher->decrypt(
   73: 				  pack("H16",substr($uri,$encidx,16))
   74: 				  );
   75:     }
   76:     return substr($decuri,0,$cmdlength);
   77: }
   78: 
   79: sub encrypted {
   80:     my $uri=shift;
   81:     my $cmdlength=length($uri);
   82:     my $encuri='';
   83:     my $cipher=
   84: 	new IDEA $ENV{'course.'.$ENV{'request.course.id'}.'.internal.encseed'};
   85:     for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {
   86: 	$encuri.=unpack("H16",
   87: 			$cipher->encrypt(substr($uri,$encidx,8)));
   88:     }
   89:     return '/enc/'.$cmdlength.'/'.&Apache::lonnet::escape($encuri);
   90: }
   91: 
   92: 1;
   93: __END__
   94: 
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