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&check_encrypt() now accepts a reference to a scalar  - i.e, the same as check_decrypt().

    1: # The LearningOnline Network
    2: # URL translation for encrypted filenames
    3: #
    4: # $Id: lonenc.pm,v 1.18 2006/12/08 22:04:57 raeburn 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::lonnet;
   33: use Crypt::IDEA;
   34: use Time::HiRes qw(gettimeofday);
   35: use LONCAPA;
   36:  
   37: sub encryptseed {
   38:     my $seed=$env{'course.'.$env{'request.course.id'}.'.internal.encseed'};
   39:     $seed=~s/[^0-9a-f]/0/g;
   40:     $seed.='0123456789abcdef';
   41:     $seed=substr($seed.$seed,0,32);
   42:     return pack("H32",$seed);
   43: }
   44: 
   45: sub unencrypted {
   46:     my $uri=shift;
   47:     $uri=~s/^\/enc\/(\d+)\///;
   48:     my $cmdlength=$1;
   49:     # strip any added extension
   50:     $uri=~s/\.[^.]*//;
   51:     my $seed=&encryptseed();
   52:     unless ($seed) {
   53: 	return '/'.$uri;
   54:     }
   55:     $uri=&unescape($uri);
   56:     my $cipher=new IDEA $seed;
   57:     my $decuri='';
   58:     for (my $encidx=0;$encidx<length($uri);$encidx+=16) {
   59: 	$decuri.=$cipher->decrypt(
   60: 				  pack("H16",substr($uri,$encidx,16))
   61: 				  );
   62:     }
   63:     $env{'request.enc'}=1;
   64:     $decuri=&remove_noise($decuri);
   65:     return substr($decuri,0,$cmdlength);
   66: }
   67: 
   68: # add a randomish character after every 4th caharacter
   69: sub add_noise {
   70:     my ($uri)=@_;
   71:     my @noise=split(/(.)/,(&gettimeofday())[1]);
   72:     my $noisy;
   73:     my $i;
   74:     foreach my $chunk (split(/(....)/,$uri)) {
   75: 	$noisy.=$chunk;
   76: 	$noisy.=$noise[($i++)%(scalar@noise)];
   77:     }
   78:     return $noisy;
   79: }
   80: 
   81: # remove every fifth character
   82: sub remove_noise {
   83:     my ($uri)=@_;
   84:     my $clean;
   85:     foreach my $chunk (split(/(....)./,$uri)) { $clean.=$chunk; }
   86:     return $clean;
   87: }
   88: 
   89: sub encrypted {
   90:     my ($uri,$force_enc) = @_;
   91:     if (!$force_enc && $env{'request.role.adv'}) { return($uri); }
   92:     my $seed=&encryptseed();
   93:     unless ($seed) {
   94: 	return $uri;
   95:     }
   96:     my $cmdlength=length($uri);
   97:     # add noise before enc so that that same url's look different
   98:     $uri=&add_noise($uri);
   99:     my $noiselength=length($uri);
  100:     $uri.=time;
  101:     my $encuri='';
  102:     my $cipher=new IDEA $seed;
  103:     for (my $encidx=0;$encidx<=$noiselength;$encidx+=8) {
  104: 	$encuri.=unpack("H16",
  105: 			$cipher->encrypt(substr($uri,$encidx,8)));
  106:     }
  107:     return '/enc/'.$cmdlength.'/'.&escape($encuri);
  108: }
  109: 
  110: sub check_encrypt {
  111:     my $str=shift;
  112:     if (ref($str)) {
  113:         if ($env{'request.enc'}) { $$str = &Apache::lonenc::encrypted($$str); }
  114:         return;
  115:     } else {
  116:         if ($env{'request.enc'}) { return &Apache::lonenc::encrypted($str); }
  117:     }
  118:     return $str;
  119: }
  120: 
  121: sub check_decrypt {
  122:     my ($str)=@_;
  123:     if (ref($str)) {
  124: 	if ($$str=~m|^/enc/|) { $$str=&Apache::lonenc::unencrypted($$str); }
  125: 	return;
  126:     }
  127:     if ($str=~m|^/enc/|) { return &Apache::lonenc::unencrypted($str); }
  128:     return $str;
  129: }
  130: 
  131: sub encrypt_ref {
  132:     my ($token,$elements,$force_enc)=@_;
  133:     my $html;
  134:     if ($force_enc || $env{'request.enc'}) {
  135: 	while (my ($name,$value)= each(%{ $elements })) {
  136: 	    if (!$value) { next; }
  137: 	    my $href=&Apache::lonnet::hreflocation($Apache::lonxml::pwd[-1],$value);
  138: 	    if ($href !~ /^http:/) {
  139: 		# IE really wants an extension
  140: 		my ($extension) = ($href =~ m/(\.[^.]*)$/);
  141: 		$href = &Apache::lonenc::encrypted($href,$force_enc);
  142: 		$href .= $extension;
  143: 	    }
  144: 	    $token->[2]->{$name}=$href;
  145: 	}
  146: 	delete($token->[2]->{'encrypturl'});
  147: 	$html = &Apache::edit::rebuild_tag($token);
  148:     } else {
  149: 	$html = $token->[4];
  150:     }
  151:     return $html;
  152: }
  153: 1;
  154: __END__
  155: 
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