system/core/Input.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * NOTICE OF LICENSE
 *
 * Licensed under the Open Software License version 3.0
 *
 * This source file is subject to the Open Software License (OSL 3.0) that is
 * bundled with this package in the files license.txt / license.rst.  It is
 * also available through the world wide web at this URL:
 * http://opensource.org/licenses/OSL-3.0
 * If you did not receive a copy of the license and are unable to obtain it
 * through the world wide web, please send an email to
 * licensing@ellislab.com so we can send you a copy immediately.
 *
 * @package		CodeIgniter
 * @author		EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
 * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

/**
 * Input Class
 *
 * Pre-processes global input data for security
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Input
 * @author		EllisLab Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/input.html
 */
class CI_Input {

	/**
	 * IP address of the current user
	 *
	 * @var string
	 */
	public $ip_address				= FALSE;
	/**
	 * user agent (web browser) being used by the current user
	 *
	 * @var string
	 */
	public $user_agent				= FALSE;
	/**
	 * If FALSE, then $_GET will be set to an empty array
	 *
	 * @var bool
	 */
	protected $_allow_get_array		= TRUE;
	/**
	 * If TRUE, then newlines are standardized
	 *
	 * @var bool
	 */
	protected $_standardize_newlines	= TRUE;
	/**
	 * Determines whether the XSS filter is always active when GET, POST or COOKIE data is encountered
	 * Set automatically based on config setting
	 *
	 * @var bool
	 */
	protected $_enable_xss			= FALSE;
	/**
	 * Enables a CSRF cookie token to be set.
	 * Set automatically based on config setting
	 *
	 * @var bool
	 */
	protected $_enable_csrf			= FALSE;
	/**
	 * List of all HTTP request headers
	 *
	 * @var array
	 */
	protected $headers			= array();

	/**
	 * Constructor
	 *
	 * Sets whether to globally enable the XSS processing
	 * and whether to allow the $_GET array
	 */
	public function __construct()
	{
		log_message('debug', 'Input Class Initialized');

		$this->_allow_get_array	= (config_item('allow_get_array') === TRUE);
		$this->_enable_xss	= (config_item('global_xss_filtering') === TRUE);
		$this->_enable_csrf	= (config_item('csrf_protection') === TRUE);

		global $SEC;
		$this->security =& $SEC;

		// Do we need the UTF-8 class?
		if (UTF8_ENABLED === TRUE)
		{
			global $UNI;
			$this->uni =& $UNI;
		}

		// Sanitize global arrays
		$this->_sanitize_globals();
	}

	// --------------------------------------------------------------------

	/**
	 * Fetch from array
	 *
	 * This is a helper function to retrieve values from global arrays
	 *
	 * @param	array
	 * @param	string
	 * @param	bool
	 * @return	string
	 */
	protected function _fetch_from_array(&$array, $index = '', $xss_clean = FALSE)
	{
		if ( ! isset($array[$index]))
		{
			return FALSE;
		}

		if ($xss_clean === TRUE)
		{
			return $this->security->xss_clean($array[$index]);
		}

		return $array[$index];
	}

	// --------------------------------------------------------------------

	/**
	* Fetch an item from the GET array
	*
	* @param	string
	* @param	bool
	* @return	string
	*/
	public function get($index = NULL, $xss_clean = FALSE)
	{
		// Check if a field has been provided
		if ($index === NULL && ! empty($_GET))
		{
			$get = array();

			// loop through the full _GET array
			foreach (array_keys($_GET) as $key)
			{
				$get[$key] = $this->_fetch_from_array($_GET, $key, $xss_clean);
			}
			return $get;
		}

		return $this->_fetch_from_array($_GET, $index, $xss_clean);
	}

	// --------------------------------------------------------------------

	/**
	* Fetch an item from the POST array
	*
	* @param	string
	* @param	bool
	* @return	string
	*/
	public function post($index = NULL, $xss_clean = FALSE)
	{
		// Check if a field has been provided
		if ($index === NULL && ! empty($_POST))
		{
			$post = array();

			// Loop through the full _POST array and return it
			foreach (array_keys($_POST) as $key)
			{
				$post[$key] = $this->_fetch_from_array($_POST, $key, $xss_clean);
			}
			return $post;
		}

		return $this->_fetch_from_array($_POST, $index, $xss_clean);
	}


	// --------------------------------------------------------------------

	/**
	* Fetch an item from either the GET array or the POST
	*
	* @param	string	The index key
	* @param	bool	XSS cleaning
	* @return	string
	*/
	public function get_post($index = '', $xss_clean = FALSE)
	{
		return isset($_POST[$index])
			? $this->post($index, $xss_clean)
			: $this->get($index, $xss_clean);
	}

	// --------------------------------------------------------------------

	/**
	* Fetch an item from the COOKIE array
	*
	* @param	string
	* @param	bool
	* @return	string
	*/
	public function cookie($index = '', $xss_clean = FALSE)
	{
		return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
	}

	// ------------------------------------------------------------------------

	/**
	* Set cookie
	*
	* Accepts six parameter, or you can submit an associative
	* array in the first parameter containing all the values.
	*
	* @param	mixed
	* @param	string	the value of the cookie
	* @param	string	the number of seconds until expiration
	* @param	string	the cookie domain.  Usually:  .yourdomain.com
	* @param	string	the cookie path
	* @param	string	the cookie prefix
	* @param	bool	true makes the cookie secure
	* @return	void
	*/
	public function set_cookie($name = '', $value = '', $expire = '', $domain = '', $path = '/', $prefix = '', $secure = FALSE)
	{
		if (is_array($name))
		{
			// always leave 'name' in last place, as the loop will break otherwise, due to $$item
			foreach (array('value', 'expire', 'domain', 'path', 'prefix', 'secure', 'name') as $item)
			{
				if (isset($name[$item]))
				{
					$$item = $name[$item];
				}
			}
		}

		if ($prefix == '' && config_item('cookie_prefix') != '')
		{
			$prefix = config_item('cookie_prefix');
		}
		if ($domain == '' && config_item('cookie_domain') != '')
		{
			$domain = config_item('cookie_domain');
		}
		if ($path == '/' && config_item('cookie_path') !== '/')
		{
			$path = config_item('cookie_path');
		}
		if ($secure == FALSE && config_item('cookie_secure') != FALSE)
		{
			$secure = config_item('cookie_secure');
		}

		if ( ! is_numeric($expire))
		{
			$expire = time() - 86500;
		}
		else
		{
			$expire = ($expire > 0) ? time() + $expire : 0;
		}

		setcookie($prefix.$name, $value, $expire, $path, $domain, $secure);
	}

	// --------------------------------------------------------------------

	/**
	* Fetch an item from the SERVER array
	*
	* @param	string
	* @param	bool
	* @return	string
	*/
	public function server($index = '', $xss_clean = FALSE)
	{
		return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
	}

	// --------------------------------------------------------------------

	/**
	* Fetch the IP Address
	*
	* @return	string
	*/
	public function ip_address()
	{
		if ($this->ip_address !== FALSE)
		{
			return $this->ip_address;
		}

		if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))
		{
			$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
			$proxies = is_array($proxies) ? $proxies : array($proxies);

			$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
		}
		elseif ( ! $this->server('HTTP_CLIENT_IP') && $this->server('REMOTE_ADDR'))
		{
			$this->ip_address = $_SERVER['REMOTE_ADDR'];
		}
		elseif ($this->server('REMOTE_ADDR') && $this->server('HTTP_CLIENT_IP'))
		{
			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
		}
		elseif ($this->server('HTTP_CLIENT_IP'))
		{
			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
		}
		elseif ($this->server('HTTP_X_FORWARDED_FOR'))
		{
			$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
		}

		if ($this->ip_address === FALSE)
		{
			return $this->ip_address = '0.0.0.0';
		}

		if (strpos($this->ip_address, ',') !== FALSE)
		{
			$x = explode(',', $this->ip_address);
			$this->ip_address = trim(end($x));
		}

		if ( ! $this->valid_ip($this->ip_address))
		{
			return $this->ip_address = '0.0.0.0';
		}

		return $this->ip_address;
	}

	// --------------------------------------------------------------------

	/**
	* Validate IP Address
	*
	* Updated version suggested by Geert De Deckere
	*
	* @param	string
	* @return	bool
	*/
	public function valid_ip($ip)
	{
		// if php version >= 5.2, use filter_var to check validate ip.
		if (function_exists('filter_var'))
		{
			return (bool) filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4);
		}

		$ip_segments = explode('.', $ip);

		// Always 4 segments needed
		if (count($ip_segments) !== 4)
		{
			return FALSE;
		}
		// IP can not start with 0
		if ($ip_segments[0][0] == '0')
		{
			return FALSE;
		}
		// Check each segment
		foreach ($ip_segments as $segment)
		{
			// IP segments must be digits and can not be
			// longer than 3 digits or greater then 255
			if ($segment == '' OR preg_match('/[^0-9]/', $segment) OR $segment > 255 OR strlen($segment) > 3)
			{
				return FALSE;
			}
		}

		return TRUE;
	}

	// --------------------------------------------------------------------

	/**
	* User Agent
	*
	* @return	string
	*/
	public function user_agent()
	{
		if ($this->user_agent !== FALSE)
		{
			return $this->user_agent;
		}

		return $this->user_agent = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : FALSE;
	}

	// --------------------------------------------------------------------

	/**
	* Sanitize Globals
	*
	* This function does the following:
	*
	* - Unsets $_GET data (if query strings are not enabled)
	* - Unsets all globals if register_globals is enabled
	* - Standardizes newline characters to \n
	*
	* @return	void
	*/
	protected function _sanitize_globals()
	{
		// It would be "wrong" to unset any of these GLOBALS.
		$protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST',
					'_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
					'system_folder', 'application_folder', 'BM', 'EXT',
					'CFG', 'URI', 'RTR', 'OUT', 'IN'
				);

		// Unset globals for securiy.
		// This is effectively the same as register_globals = off
		foreach (array($_GET, $_POST, $_COOKIE) as $global)
		{
			if ( ! is_array($global))
			{
				if ( ! in_array($global, $protected))
				{
					global $$global;
					$$global = NULL;
				}
			}
			else
			{
				foreach ($global as $key => $val)
				{
					if ( ! in_array($key, $protected))
					{
						global $$key;
						$$key = NULL;
					}
				}
			}
		}

		// Is $_GET data allowed? If not we'll set the $_GET to an empty array
		if ($this->_allow_get_array == FALSE)
		{
			$_GET = array();
		}
		elseif (is_array($_GET) && count($_GET) > 0)
		{
			foreach ($_GET as $key => $val)
			{
				$_GET[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
			}
		}

		// Clean $_POST Data
		if (is_array($_POST) && count($_POST) > 0)
		{
			foreach ($_POST as $key => $val)
			{
				$_POST[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
			}
		}

		// Clean $_COOKIE Data
		if (is_array($_COOKIE) && count($_COOKIE) > 0)
		{
			// Also get rid of specially treated cookies that might be set by a server
			// or silly application, that are of no use to a CI application anyway
			// but that when present will trip our 'Disallowed Key Characters' alarm
			// http://www.ietf.org/rfc/rfc2109.txt
			// note that the key names below are single quoted strings, and are not PHP variables
			unset($_COOKIE['$Version']);
			unset($_COOKIE['$Path']);
			unset($_COOKIE['$Domain']);

			foreach ($_COOKIE as $key => $val)
			{
				$_COOKIE[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
			}
		}

		// Sanitize PHP_SELF
		$_SERVER['PHP_SELF'] = strip_tags($_SERVER['PHP_SELF']);

		// CSRF Protection check
		if ($this->_enable_csrf == TRUE)
		{
			$this->security->csrf_verify();
		}

		log_message('debug', 'Global POST and COOKIE data sanitized');
	}

	// --------------------------------------------------------------------

	/**
	* Clean Input Data
	*
	* This is a helper function. It escapes data and
	* standardizes newline characters to \n
	*
	* @param	string
	* @return	string
	*/
	protected function _clean_input_data($str)
	{
		if (is_array($str))
		{
			$new_array = array();
			foreach ($str as $key => $val)
			{
				$new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
			}
			return $new_array;
		}

		/* We strip slashes if magic quotes is on to keep things consistent

		   NOTE: In PHP 5.4 get_magic_quotes_gpc() will always return 0 and
			 it will probably not exist in future versions at all.
		*/
		if ( ! is_php('5.4') && get_magic_quotes_gpc())
		{
			$str = stripslashes($str);
		}

		// Clean UTF-8 if supported
		if (UTF8_ENABLED === TRUE)
		{
			$str = $this->uni->clean_string($str);
		}

		// Remove control characters
		$str = remove_invisible_characters($str);

		// Should we filter the input data?
		if ($this->_enable_xss === TRUE)
		{
			$str = $this->security->xss_clean($str);
		}

		// Standardize newlines if needed
		if ($this->_standardize_newlines == TRUE && strpos($str, "\r") !== FALSE)
		{
			return str_replace(array("\r\n", "\r", "\r\n\n"), PHP_EOL, $str);
		}

		return $str;
	}

	// --------------------------------------------------------------------

	/**
	* Clean Keys
	*
	* This is a helper function. To prevent malicious users
	* from trying to exploit keys we make sure that keys are
	* only named with alpha-numeric text and a few other items.
	*
	* @param	string
	* @return	string
	*/
	protected function _clean_input_keys($str)
	{
		if ( ! preg_match('/^[a-z0-9:_\/-]+$/i', $str))
		{
			set_status_header(503);
			exit('Disallowed Key Characters.');
		}

		// Clean UTF-8 if supported
		if (UTF8_ENABLED === TRUE)
		{
			return $this->uni->clean_string($str);
		}

		return $str;
	}

	// --------------------------------------------------------------------

	/**
	 * Request Headers
	 *
	 * In Apache, you can simply call apache_request_headers(), however for
	 * people running other webservers the function is undefined.
	 *
	 * @param	bool XSS cleaning
	 * @return	array
	 */
	public function request_headers($xss_clean = FALSE)
	{
		// Look at Apache go!
		if (function_exists('apache_request_headers'))
		{
			$headers = apache_request_headers();
		}
		else
		{
			$headers['Content-Type'] = isset($_SERVER['CONTENT_TYPE']) ? $_SERVER['CONTENT_TYPE'] : @getenv('CONTENT_TYPE');

			foreach ($_SERVER as $key => $val)
			{
				if (strpos($key, 'HTTP_') === 0)
				{
					$headers[substr($key, 5)] = $this->_fetch_from_array($_SERVER, $key, $xss_clean);
				}
			}
		}

		// take SOME_HEADER and turn it into Some-Header
		foreach ($headers as $key => $val)
		{
			$key = str_replace('_', ' ', strtolower($key));
			$key = str_replace(' ', '-', ucwords($key));

			$this->headers[$key] = $val;
		}

		return $this->headers;
	}

	// --------------------------------------------------------------------

	/**
	 * Get Request Header
	 *
	 * Returns the value of a single member of the headers class member
	 *
	 * @param	string	array key for $this->headers
	 * @param	bool	XSS Clean or not
	 * @return	mixed	FALSE on failure, string on success
	 */
	public function get_request_header($index, $xss_clean = FALSE)
	{
		if (empty($this->headers))
		{
			$this->request_headers();
		}

		if ( ! isset($this->headers[$index]))
		{
			return FALSE;
		}

		return ($xss_clean === TRUE)
			? $this->security->xss_clean($this->headers[$index])
			: $this->headers[$index];
	}

	// --------------------------------------------------------------------

	/**
	 * Is ajax Request?
	 *
	 * Test to see if a request contains the HTTP_X_REQUESTED_WITH header
	 *
	 * @return 	bool
	 */
	public function is_ajax_request()
	{
		return ( ! empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) === 'xmlhttprequest');
	}

	// --------------------------------------------------------------------

	/**
	 * Is cli Request?
	 *
	 * Test to see if a request was made from the command line
	 *
	 * @return 	bool
	 */
	public function is_cli_request()
	{
		return (php_sapi_name() === 'cli' OR defined('STDIN'));
	}

	// --------------------------------------------------------------------

	/**
	 * Get Request Method
	 *
	 * Return the Request Method
	 *
	 * @param	bool	uppercase or lowercase
	 * @return 	mixed
	 */
	public function method($upper = FALSE)
	{
		return ($upper)
			? strtoupper($this->server('REQUEST_METHOD'))
			: strtolower($this->server('REQUEST_METHOD'));
	}

}

/* End of file Input.php */
/* Location: ./system/core/Input.php */