我們開始分析core/Input.php。
它會先針對使用者傳入的值進行處理、確保系統安全。
_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
$this->_sanitize_globals();
}
// --------------------------------------------------------------------
/**
* Fetch from array
*
* This is a helper function to retrieve values from global arrays
*
* @access private
* @param array
* @param string
* @param bool
* @return string
*/
function _fetch_from_array(&$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];
}
整個Input類別的一大重點。
在CI中，要取得使用者輸入值，都是$this->input->get或是$this->input->post之類的。
這些函式基本上都是去呼叫這個_fetch_from_array函式，允許你將$_GET、$_POST變數經由xss_clean處理之後回傳。
注意：xss_clean函數做的檢查非常多，主要是防止
這份列表上的攻擊行為。
// --------------------------------------------------------------------
/**
* Fetch an item from the GET array
*
* @access public
* @param string
* @param bool
* @return string
*/
function get($index = NULL, $xss_clean = FALSE)
{
// Check if a field has been provided
if ($index === NULL AND ! 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, $xss_clean);
}
與直接使用$_GET的唯一不同，在於第二個參數傳入TRUE可以進行xss過濾。
// --------------------------------------------------------------------
/**
* Fetch an item from the POST array
*
* @access public
* @param string
* @param bool
* @return string
*/
function post($index = NULL, $xss_clean = FALSE)
{
// Check if a field has been provided
if ($index === NULL AND ! 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, $xss_clean);
}
與直接使用$_POST的唯一不同，在於第二個參數傳入TRUE可以進行xss過濾。
// --------------------------------------------------------------------
/**
* Fetch an item from either the GET array or the POST
*
* @access public
* @param string The index key
* @param bool XSS cleaning
* @return string
*/
function get_post($index = '', $xss_clean = FALSE)
{
if ( ! isset($_POST[$index]) )
{
return $this->get($index, $xss_clean);
}
else
{
return $this->post($index, $xss_clean);
}
}
PHP內建的$_REQUEST變數讓懶人可以直接拿$_GET, $_POST, $_COOKIE變數的值。
這個函數怎麼不連$_COOKIE的值一起抓？不是很懶？囧。
// --------------------------------------------------------------------
/**
* Fetch an item from the COOKIE array
*
* @access public
* @param string
* @param bool
* @return string
*/
function cookie($index = '', $xss_clean = FALSE)
{
return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
}
與直接使用$_COOKIE的唯一不同，在於第二個參數傳入TRUE可以進行xss過濾。
// ------------------------------------------------------------------------
/**
* Set cookie
*
* Accepts six parameter, or you can submit an associative
* array in the first parameter containing all the values.
*
* @access public
* @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
*/
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 == '' AND config_item('cookie_prefix') != '')
{
$prefix = config_item('cookie_prefix');
}
if ($domain == '' AND config_item('cookie_domain') != '')
{
$domain = config_item('cookie_domain');
}
if ($path == '/' AND config_item('cookie_path') != '/')
{
$path = config_item('cookie_path');
}
if ($secure == FALSE AND 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, $secure);
}
// --------------------------------------------------------------------
/**
* Fetch an item from the SERVER array
*
* @access public
* @param string
* @param bool
* @return string
*/
function server($index = '', $xss_clean = FALSE)
{
return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
}
$_SERVER變數一樣用_fetch_from_array包過一次，主要好處是它們會確認並檢視這些項目是否已被設定並且在未設定時回傳 false。
這讓你可以方便地使用資料而不必預先測試它們是否存在。
$_SERVER變數的值都是伺服器產生、與使用者無關。所以完全不需要xss過濾。
雖然用_fetch_from_array包過，但$xss_clean參數其實沒意義。
// --------------------------------------------------------------------
/**
* Fetch the IP Address
*
* @return string
*/
public function ip_address()
{
if ($this->ip_address !== FALSE)
{
return $this->ip_address;
}
$proxy_ips = config_item('proxy_ips');
if ( ! empty($proxy_ips))
{
$proxy_ips = explode(',', str_replace(' ', '', $proxy_ips));
foreach (array('HTTP_X_FORWARDED_FOR', 'HTTP_CLIENT_IP', 'HTTP_X_CLIENT_IP', 'HTTP_X_CLUSTER_CLIENT_IP') as $header)
{
if (($spoof = $this->server($header)) !== FALSE)
{
// Some proxies typically list the whole chain of IP
// addresses through which the client has reached us.
// e.g. client_ip, proxy_ip1, proxy_ip2, etc.
if (strpos($spoof, ',') !== FALSE)
{
$spoof = explode(',', $spoof, 2);
$spoof = $spoof[0];
}
if ( ! $this->valid_ip($spoof))
{
$spoof = FALSE;
}
else
{
break;
}
}
}
$this->ip_address = ($spoof !== FALSE && in_array($_SERVER['REMOTE_ADDR'], $proxy_ips, TRUE))
? $spoof : $_SERVER['REMOTE_ADDR'];
}
else
{
$this->ip_address = $_SERVER['REMOTE_ADDR'];
}
if ( ! $this->valid_ip($this->ip_address))
{
$this->ip_address = '0.0.0.0';
}
return $this->ip_address;
}
// --------------------------------------------------------------------
/**
* Validate IP Address
*
* @access public
* @param string
* @param string ipv4 or ipv6
* @return bool
*/
public function valid_ip($ip, $which = '')
{
$which = strtolower($which);
// First check if filter_var is available
if (is_callable('filter_var'))
{
switch ($which) {
case 'ipv4':
$flag = FILTER_FLAG_IPV4;
break;
case 'ipv6':
$flag = FILTER_FLAG_IPV6;
break;
default:
$flag = '';
break;
}
return (bool) filter_var($ip, FILTER_VALIDATE_IP, $flag);
}
if ($which !== 'ipv6' && $which !== 'ipv4')
{
if (strpos($ip, ':') !== FALSE)
{
$which = 'ipv6';
}
elseif (strpos($ip, '.') !== FALSE)
{
$which = 'ipv4';
}
else
{
return FALSE;
}
}
$func = '_valid_'.$which;
return $this->$func($ip);
}
// --------------------------------------------------------------------
/**
* Validate IPv4 Address
*
* Updated version suggested by Geert De Deckere
*
* @access protected
* @param string
* @return bool
*/
protected function _valid_ipv4($ip)
{
$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;
}
// --------------------------------------------------------------------
/**
* Validate IPv6 Address
*
* @access protected
* @param string
* @return bool
*/
protected function _valid_ipv6($str)
{
// 8 groups, separated by :
// 0-ffff per group
// one set of consecutive 0 groups can be collapsed to ::
$groups = 8;
$collapsed = FALSE;
$chunks = array_filter(
preg_split('/(:{1,2})/', $str, NULL, PREG_SPLIT_DELIM_CAPTURE)
);
// Rule out easy nonsense
if (current($chunks) == ':' OR end($chunks) == ':')
{
return FALSE;
}
// PHP supports IPv4-mapped IPv6 addresses, so we'll expect those as well
if (strpos(end($chunks), '.') !== FALSE)
{
$ipv4 = array_pop($chunks);
if ( ! $this->_valid_ipv4($ipv4))
{
return FALSE;
}
$groups--;
}
while ($seg = array_pop($chunks))
{
if ($seg[0] == ':')
{
if (--$groups == 0)
{
return FALSE; // too many groups
}
if (strlen($seg) > 2)
{
return FALSE; // long separator
}
if ($seg == '::')
{
if ($collapsed)
{
return FALSE; // multiple collapsed
}
$collapsed = TRUE;
}
}
elseif (preg_match("/[^0-9a-f]/i", $seg) OR strlen($seg) > 4)
{
return FALSE; // invalid segment
}
}
return $collapsed OR $groups == 1;
}
// --------------------------------------------------------------------
/**
* User Agent
*
* @access public
* @return string
*/
function user_agent()
{
if ($this->user_agent !== FALSE)
{
return $this->user_agent;
}
$this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];
return $this->user_agent;
}
// --------------------------------------------------------------------
/**
* 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
*
* @access private
* @return void
*/
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)
{
$_GET = array();
}
else
{
if (is_array($_GET) AND 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) AND 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) AND 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 on HTTP requests
if ($this->_enable_csrf == TRUE && ! $this->is_cli_request())
{
$this->security->csrf_verify();
}
log_message('debug', "Global POST and COOKIE data sanitized");
}
// --------------------------------------------------------------------
/**
* Clean Input Data
*
* This is a helper function. It escapes data and
* standardizes newline characters to \n
*
* @access private
* @param string
* @return string
*/
function _clean_input_data($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 ($this->_standardize_newlines == TRUE)
{
if (strpos($str, "\r") !== FALSE)
{
$str = str_replace(array("\r\n", "\r", "\r\n\n"), PHP_EOL, $str);
}
}
return $str;
}
// --------------------------------------------------------------------
/**
* Clean Keys
*
* This is a helper function. To prevent malicious users
* from trying to exploit keys we make sure that keys are
* only named with alpha-numeric text and a few other items.
*
* @access private
* @param string
* @return string
*/
function _clean_input_keys($str)
{
if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str))
{
exit('Disallowed Key Characters.');
}
// Clean UTF-8 if supported
if (UTF8_ENABLED === TRUE)
{
$str = $this->uni->clean_string($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 => $val)
{
if (strncmp($key, 'HTTP_', 5) === 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 $this->headers
* @param boolean XSS Clean or not
* @return mixed FALSE on failure, string on success
*/
public function get_request_header($index, $xss_clean = FALSE)
{
if (empty($this->headers))
{
$this->request_headers();
}
if ( ! isset($this->headers[$index]))
{
return FALSE;
}
if ($xss_clean === TRUE)
{
return $this->security->xss_clean($this->headers[$index]);
}
return $this->headers[$index];
}
// --------------------------------------------------------------------
/**
* Is ajax Request?
*
* Test to see if a request contains the HTTP_X_REQUESTED_WITH header
*
* @return boolean
*/
public function is_ajax_request()
{
return ($this->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'));
}
}
/* End of file Input.php */
/* Location: ./system/core/Input.php */