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<?php
/**
 * @name Rex
 * @version 1.1
 * @author David Sopas Ferreira <coder at davidsopas dot com>
 * @copyright 2008
 *
 * Changelog:
 *
 * v1.1
 * - Proxy port scan can be disabled (in some cases, it blocks users that have port 80 open in their router configuration)
 * - Added checkspamcop() that checks if a user IP is registered as spammer on Spamcop.net (can be enabled/diabled)
 * - Function filtraxss() renamed to checkxss() because it really checks the presence of malicious xss doesn't filter anything
 * - Function checkxss() only accepts arrays
 * - Added filterxss() that removes or disables tags
 * - Added checksize_db_data() that can be used to check for data size before inserting in database
 * - Added filtersql() that escapes special characters in a string for use in a SQL statement
 * - Portuguese variables renamed to english for better understanding the code to a larger community
 *
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */
 
 class Rex
 {
 // Set the values to your needs (fit your needs)
 private $logfile = "rexlog.txt"; // The log file, I recommend to put it on a protected directory
 private $timeout = 5; // Timeout for the IP verification
 private $lockscan = 1; // 0 - enable proxy port scan | 1 - disable proxy port scan
 private $lockspamcop = 0; // 0 - enable spamcop check | 1 - disable spamcop check
 // -------------------------------------------------------------------------------------------------
 
 // Function that checks if the IP is listed on any spam blacklist on spamcop.net
 public function checkspamcop($ip)
 {
 if ($this->lockspamcop == 0)
 {
 $handle = @fopen("http://www.spamcop.net/w3m?action=checkblock&ip=$ip", "rb");
 stream_set_timeout($handle, $timeout);
 $contents = "";
 while (!feof($handle))
 {
 $contents .= @fread($handle, 8192);
 }
 fclose($handle);
 if (preg_match("/$ip listed in [\w]*\.spamcop\.net/", $contents))
 {
 return true;
 } else
 {
 return false;
 }
 }
 }
 
 // Function that checks if the IP is possibly a PROXY
 public function checkip($ip)
 {
 if ($this->lockscan == 0)
 {
 // Array with the proxy ports, you can add more if you want
 $ports = array(80, 3128, 8080);
 // Flag to be returned: 0 safe - 1 open and unsafe
 $flag = 0;
 foreach ($ports as $port)
 {
 @$fp = fsockopen($ip, $port, $errno, $errstr, $this->timeout);
 // Check if fp return something
 if (!empty($fp))
 {
 $flag = 1;
 fclose($fp);
 }
 }
 return $flag;
 }
 }
 
 // Function that checks $_GET , $_POST , $_SESSION , $_COOKIE or any other arrays for XSS malicious code
 public function checkxss($filter)
 {
 if (is_array($filter))
 {
 foreach ($filter as $check_array)
 {
 if ((eregi("<[^>]*script*\"?[^>]*>", $check_array)) || (eregi("<[^>]*object*\"?[^>]*>",
 $check_array)) || (eregi("<[^>]*iframe*\"?[^>]*>", $check_array)) || (eregi("<[^>]*applet*\"?[^>]*>",
 $check_array)) || (eregi("<[^>]*meta*\"?[^>]*>", $check_array)) || (eregi("<[^>]*style*\"?[^>]*>",
 $check_array)) || (eregi("<[^>]*form*\"?[^>]*>", $check_array)) || (eregi("\([^>]*\"?[^)]*\)",
 $check_array)) || (eregi("\"", $check_array)))
 {
 return true;
 } else
 {
 return false;
 }
 }
 unset($check_array);
 } else
 {
 echo "ERROR: function checkxss() only can treat arrays.";
 }
 }
 
 // Function that filters tags, preventing HTML injections or XSS attacks on variables
 // Option: 0- removes tags 1- disables html
 public function filterxss($filter, $option)
 {
 if ($option == 0)
 {
 $filtered = strip_tags($filter);
 return $filtered;
 } elseif ($option == 1)
 {
 $filtered = htmlspecialchars($filter);
 return $filtered;
 } else
 {
 return "ERROR: function filterxss() doesn't have that option available.";
 }
 }
 
 // Function that checks for the right size of data that will be inserted in the database
 public function checksize_db_data($data, $minsize, $maxsize)
 {
 if (strlen($data) < $minsize || strlen($data) > $maxsize)
 {
 return false;
 } else
 {
 return true;
 }
 }
 
 // Function that escapes special characters in a string for use in a SQL statement
 public function filtersql($data)
 {
 // Strips whitespaces or other characters from the beginning and end of $data
 $filtered = trim($data);
 $filtered = mysql_real_escape_string($filtered);
 return $filtered;
 }
 
 // Function that records all the data in a log file
 public function recordlog($ip, $error)
 {
 if (is_writable($this->logfile))
 {
 if ($this->lockscan == 0)
 {
 if ($this->checkip("$ip") == 1)
 {
 $proxy = "Possible PROXY";
 } else
 {
 $proxy = "";
 }
 }
 if ($this->lockspamcop == 0)
 {
 if ($this->checkspamcop("$ip") == true)
 {
 $spamcop = "(IP is listed as spammer on Spamcop.net)";
 } else
 {
 $spamcop = "";
 }
 }
 
 $fp = fopen($this->logfile, 'a+');
 
 // Data that will be stored in the log file
 $information = "[IP]: " . $ip . " $proxy " . $spamcop;
 $information .= " [Date and time]: " . date("Y/m/d - H:i:s");
 $information .= " [Error]: " . $error . "\n\n";
 fwrite($fp, $information);
 fclose($fp);
 } else
 {
 echo "ERROR: Log file don't have write permissions, please fix it (eg: CHMOD 777 filename.txt).";
 }
 }
 }
 ?>
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