بررسی امنیت سایت در برنامه نویسی

سلام
با توجه به این که هر سایتی مطرحی که احتمال حمله و سو استفاده وجود داره نیازمند امنیت خواهد بود این تاپیک رو ایجاد کردم تا با کمک دوستان حرفه ای و هر کسی که اطلاعاتی در زمینه database, php , inject , sql script داره مسائل امنیتی در سایت و حفره های نفوذی رو بررسی کنیم (البته تا جایی که دست ماست : یعنی برنامه نویس سایت)

بهتره خودم شروع کنم (البته با اجازه اساتید محترم):
بنظر من اولین و اساسی ترین حمله ها در اینترنت از طریق sql injection صورت می گیره که با یکسری عملیات حرفه ای کدهای sql رو از طریق متود های get یا post در سرور sql اجرا می کنن.
نمی خوام وارد بحث تخصصی این مبحث بشم چون می دونم حتی توی این فروم هم چند جا بحث شده اما یه function برای جلوگیری از inject نوشتم که برای دوستان میذارم (البته اگر ایرادی داشت دوستان می تونن تکمیلش کنن)
[PHP]
function sql_quote($string)
{
if(get_magic_quotes_gpc())
{
return stripslashes($string);
}

//check if this function exists
if(function_exists( "mysql_real_escape_string" ))

{
return mysql_real_escape_string($string);
}

//for PHP version < 4.3.0 use addslashes

else
{
return addslashes($string);
}
}
[/PHP]
این تابع کاراکترهایی که در sql حالت اجرایی دارند رو تبدیل به کاراکتر های معادل و یا غیر فعال می کنه:
مثال: کاراکتر ' را به کاراکتر /' تبدیل می کنه.

برای جلوگیری از ورود کدهای html نیز می تونیم از تابع زیر استفاده کنیم تا تگ های html رو به معادل غیر اجرایی (فقط نمایشی ) تبدیل کنه
مثال: > رو به &lt; تبدیل می کنه

تابع:
[PHP]
function htmlspecialchars_uni($message)
{
$message = preg_replace("#&(?!\#[0-9]+;)#si", "&amp;", $message); // Fix & but allow unicode
$message = str_replace("<","&lt;",$message);
$message = str_replace(">","&gt;",$message);
$message = str_replace("\"","&quot;",$message);
return $message;
}
[/PHP]

نقل قول:

---

برای جلوگیری از ورود کدهای html نیز می تونیم از تابع زیر استفاده کنیم تا تگ های html رو به معادل غیر اجرایی (فقط نمایشی ) تبدیل کنه
مثال: > رو به &lt; تبدیل می کنه

---

سلام
مرسی بابت کدهایی که قرار دادی

[php]
mysql_real_escape_string(htmlspecialchars(harchi:D ));

[/php]

مرسی حتما منتظرت هستم.

در ضمن:
یک مورد در مورد امنیت دیتابیس هم هست که شما می تونید از طریق کنترل پنل هاست و اگر دسترسی به سرور mysql داشتید از طریق تنظیمات mysql سطح دسترسی و عملیات روی دیتابیس مورد نظر را محدود کنید
مثلا drop را غیرفعال کنید.

از دوستانی تجربه دارن می خوام ضعف های امنیتی معمول و سطح بالا در یک برنامه تحت وب با php و روشهای حل اونا رو از این topic دریغ نکنند.

سلام
ما هم کدمون رو قرار دادیم :31: ( پست ویرایش شده )
==
تا چند روز دیگه یه کد آماده میکنم که خیلی توپه واسه امنیت ( جلوگیری از حملات xss و sql injection ) که تمامی GET هایی که در صفحه انجام میشه رو با یکبار اجرا امن میکنه :31: تا چند روز دیگه کد نویسیش رو تمام میکنم

تشکر//

یک کلاس session که سیشن ها رو برای کنترل بیشتر وامنیت بالاتر در دیتابیس ذخیره می کنه!
[PHP]
class dbSession
{

/**
* Constructor of class
*
* Initializes the class and starts a new session
*
* There is no need to call start_session() after instantiating this class
*
* @param integer $gc_maxlifetime the number of seconds after which data will be seen as 'garbage' and
* cleaned up on the next run of the gc (garbage collection) routine
*
* Default is specified in php.ini file
*
* @param integer $gc_probability used in conjunction with gc_divisor, is used to manage probability that
* the gc routine is started. the probability is expressed by the formula
*
* probability = $gc_probability / $gc_divisor
*
* So if $gc_probability is 1 and $gc_divisor is 100 means that there is
* a 1% chance the the gc routine will be called on each request
*
* Default is specified in php.ini file
*
* @param integer $gc_divisor used in conjunction with gc_probability, is used to manage probability
* that the gc routine is started. the probability is expressed by the formula
*
* probability = $gc_probability / $gc_divisor
*
* So if $gc_probability is 1 and $gc_divisor is 100 means that there is
* a 1% chance the the gc routine will be called on each request
*
* Default is specified in php.ini file
*
* @return void
*/
//this function run
function dbSession($gc_maxlifetime = "600", $gc_probability = "", $gc_divisor = "")
{
global $settings;
if($_COOKIE['rememberMe__ID_main'] == md5("3month"))
{
$gc_maxlifetime = 8035200;
}
elseif($_COOKIE['rememberMe__ID_main'] == md5("6month"))
{
$gc_maxlifetime = 16070400;
}
else
{
$gc_maxlifetime = $settings['session_lifetime'];
}

// if $gc_maxlifetime is specified and is an integer number
if ($gc_maxlifetime != "" && is_integer($gc_maxlifetime)) {

// set the new value
@ini_set('session.gc_maxlifetime', $gc_maxlifetime);

}

// if $gc_probability is specified and is an integer number
if ($gc_probability != "" && is_integer($gc_probability)) {

// set the new value
@ini_set('session.gc_probability', $gc_probability);

}

// if $gc_divisor is specified and is an integer number
if ($gc_divisor != "" && is_integer($gc_divisor)) {

// set the new value
@ini_set('session.gc_divisor', $gc_divisor);

}

// get session lifetime
$this->sessionLifetime = ini_get("session.gc_maxlifetime");

// register the new handler
session_set_save_handler(
array(&$this, 'open'),
array(&$this, 'close'),
array(&$this, 'read'),
array(&$this, 'write'),
array(&$this, 'destroy'),
array(&$this, 'gc')
);

register_shutdown_function('session_write_close');

// start the session
session_start();

}

/**
* Deletes all data related to the session
*
* @return void
*/
function stop()
{
$this->regenerate_id();
session_unset();
session_destroy();
}

/**
* Regenerates the session id.
*
* <b>Call this method whenever you do a privilege change!</b>
*
* @return void
*/
function regenerate_id()
{

// saves the old session's id
$oldSessionID = session_id();

// regenerates the id
// this function will create a new session, with a new id and containing the data from the old session
// but will not delete the old session
session_regenerate_id();

// because the session_regenerate_id() function does not delete the old session,
// we have to delete it manually
$this->destroy($oldSessionID);

}

/**
* Get the number of online users
*
* This is not 100% accurate. It depends on how often the garbage collector is run
*
* @return integer approximate number of users currently online
*/
function get_users_online()
{
global $db;

// counts the rows from the database
$query = $db->simple_select(TABLE_PREFIX."session_data", $fields="COUNT(session_id) as count", $conditions="online_expire > ".time()."", $options=array());

$result = $db->fetch_array($query);

// return the number of found rows
return $result["count"];

}

/**
* Custom open() function
*
* @access private
*/
function open($save_path, $session_name)
{

return true;

}

/**
* Custom close() function
*
* @access private
*/
function close()
{
return true;
}

/**
* Custom read() function
*
* @access private
*/
function read($session_id)
{
global $db;

// reads session data associated with the session id
// but only if the HTTP_USER_AGENT is the same as the one who had previously written to this session
// and if session has not expired
$result = $db->simple_select(TABLE_PREFIX."session_data", $fields="session_data", $conditions="session_id = '".$session_id."' AND http_user_agent = '".$_SERVER["HTTP_USER_AGENT"]."' AND session_expire > '".time()."'");

// if anything was found
if (is_resource($result) && @mysql_num_rows($result) > 0) {

// return found data
$fields = @mysql_fetch_assoc($result);
// don't bother with the unserialization - PHP handles this automatically
return $fields["session_data"];

}

// if there was an error return an empty string - this HAS to be an empty string
return "";

}

/**
* Custom write() function
*
* @access private
*/
function write($session_id, $session_data)
{
global $db,$settings;
// first checks if there is a session with this id

$result = $db->simple_select(TABLE_PREFIX."session_data", $fields="session_data", $conditions="session_id = '".$session_id."'");

// if there is
if (@mysql_num_rows($result) > 0) {

// update the existing session's data
// and set new expiry time

$array = array();
$array['session_data'] = $session_data;
$array['online_expire'] = (time() + $settings['online_expire_time_limit']);
$array['session_expire'] = (time() + $this->sessionLifetime);
$array['memberID'] = $_SESSION['memberID'];
$array['request_URI'] = $_SERVER['REQUEST_URI'];
$array['session_id'] = $session_id;

$result = $db->update_query(TABLE_PREFIX."session_data", $array, $where="session_id = '".$session_id."'");


// if anything happened
if (@mysql_affected_rows()) {

// return true
return true;

}

// if this session id is not in the database
} else {

// insert a new record
$array = array();
$array['session_id'] = $session_id;
$array['http_user_agent'] = $_SERVER["HTTP_USER_AGENT"];
$array['session_data'] = $session_data;
$array['IP'] = $_SERVER['REMOTE_ADDR'];
$array['online_expire'] = (time() + $settings['online_expire_time_limit']);
$array['request_URI'] = $_SERVER['REQUEST_URI'];
$array['session_expire'] = (time() + $this->sessionLifetime);

$result = $db->insert_query(TABLE_PREFIX."session_data", $array);

// if anything happened
if (@mysql_affected_rows()) {

// return an empty string
return "";

}

}

// if something went wrong, return false
return false;

}

/**
* Custom destroy() function
*
* @access private
*/
/* Destroy session record in database */
function destroy($session_id) {
$session_sql = "DELETE FROM ".TABLE_PREFIX."session_data WHERE session_id = '$session_id'";
$session_res = mysql_query($session_sql);
if (!$session_res) {
return false;
} else {
return true;
}
}


/**
* Custom gc() function (garbage collector)
*
* @access private
*/
function gc($maxlifetime)
{
global $db;

// it deletes expired sessions from database
$result = $db->delete_query(TABLE_PREFIX."session_data", $where="session_expire < '".(time() - $maxlifetime)."'");

}

}

[/PHP]

دیتابیس:
[PHP]

CREATE TABLE IF NOT EXISTS `site_session_data` (
`session_id` varchar(32) NOT NULL DEFAULT '',
`http_user_agent` varchar(255) NOT NULL DEFAULT '',
`session_data` longtext NOT NULL,
`IP` varchar(20) NOT NULL,
`memberID` bigint(20) NOT NULL,
`request_URI` varchar(450) NOT NULL,
`session_expire` int(11) NOT NULL DEFAULT '0',
`online_expire` int(11) NOT NULL,
PRIMARY KEY (`session_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
[/PHP]

البته این کلاس مربوط به kernel من هست.
برای استفاده باید برخی از توابع رو تغییر بدین مثل : simple_select update_query و...

این ها رو در فایل core.php لود کنید:
[PHP]
// PHP5 with register_long_arrays off?
if (!isset($HTTP_POST_VARS) && isset($_POST))
{
$HTTP_POST_VARS = $_POST;
$HTTP_GET_VARS = $_GET;
$HTTP_SERVER_VARS = $_SERVER;
$HTTP_COOKIE_VARS = $_COOKIE;
$HTTP_ENV_VARS = $_ENV;
$HTTP_POST_FILES = $_FILES;

// _SESSION is the only superglobal which is conditionally set
if (isset($_SESSION)){
$HTTP_SESSION_VARS = $_SESSION;
} else {
$HTTP_SESSION_VARS = array();
}
}

// PHP4.1 ?
if (!isset($_POST) && isset($HTTP_POST_VARS))
{
$_POST = $HTTP_POST_VARS;
$_GET = $HTTP_GET_VARS;
$_SERVER = $HTTP_SERVER_VARS;
$_COOKIE = $HTTP_COOKIE_VARS;
$_ENV = $HTTP_ENV_VARS;
$_FILES = $HTTP_POST_FILES;

// _SESSION is the only superglobal which is conditionally set
if (isset($HTTP_SESSION_VARS)){
$_SESSION = $HTTP_SESSION_VARS;
} else {
$_SESSION = array();
}
}

if (!isset($_REQUEST))
$_REQUEST = array_merge( $_GET, $_POST, $_COOKIE );

// _SESSION is the only superglobal which is conditionally set
if (!(isset($_SESSION ))){
$_SESSION = array();
}

// Delete Globals:
$da_kine_globals = array_merge($_GET, $_POST, $_COOKIE, $_SESSION);
unset($da_kine_globals['da_kine_globals']);
while (list($var,$val) = @each($da_kine_globals)){
unset($$var);
}
unset($val);
unset($da_kine_globals);
[/PHP]

این هم از کلاس safedata که می تونین توی فایل core لود کنید:
[PHP]
/*
Copyright (c) 2005, Matt Smith
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:

1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the distri-
bution.

3. Neither the copyright holders nor the contributors names may be
used to endorse or promote products derived from this software
without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/

/*
safedata.class.php -- version 1.0
A class that effectively disables both register_globals and magic_quotes.

It includes wrapper functions for MySQL / MySQLi's escape string
functions and for htmlentities / htmlspecialchars that allow you to use
both strings and arrays.

It can also help with HTML forms, so you can ensure that the submitted
form values are of the correct type (int, float, string, array).

License:
Berkeley Software Distribution (revised; 3-clause)

Requirements:
PHP 4 >= 4.1.0, PHP 5

Changes:
v1.0 (October 17, 2005)
- cleaned things up a bit.
- added: safedata::__init() - as part of the clean-up,
safedata::mysqli_escape_string(), safedata::is_string()
- updated: safedata::gettype(), safedata::htmlentities_array(),
safedata::htmlspecialchars_array()
- fixed: safedata::is_float() - should now be compatible
with PHP 4 >= 4.1.0 and PHP 4 < 4.2.0
- renamed: safedata::fix_register_globals() => safedata::__disable_register_globals() - internal
safedata::fix_magic_quotes() => safedata::__disable_magic_quotes() - internal
safedata::_current_version() => safedata::__version()
safedata::_release_date() => safedata::__release()
safedata::htmlentities_array() => safedata::htmlentities()
safedata::htmlspecialchars_array() => safedata::htmlspecialchars()
- legacy: safedata::htmlentities_array(), safedata::htmlspecialchars_array()
v0.3 (April 14, 2005)
- added: safedata::is_int(), safedata::is_float(), safedata::gettype(),
safedata::_current_version(), safedata::_release_date()
v0.2 (April 7, 2005)
- safedata::mysql_escape_string() has a new argument, MySQL link_id.
- added: safedata::htmlentities_array(), safedata::htmlspecialchars_array()
v0.1 (April 3, 2005)
- initial release

Class Functions:
Internal Functions
- safedata::__init()
This is called at the end of this file, just outside of the class,
and sets up a couple things that safedata will use. This function
also calls __disable_register_globals() and __disable_magic_quotes()
for you.
- safedata::__version()
Returns a string of the current version of safedata.
- safedata::__release(optional date_format)
Returns a string of the release date of safedata.
The default date_format is 'F d, Y' -- January 1, 2001

SQL-Safe Functions
- safedata::mysql_escape_string (string/array, optional link_identifier)
When used with PHP 4 >= 4.3.0, and PHP 5, mysql_real_escape_string()
will be used, otherwise, mysql_escape_string().
It can take both strings and arrays containing strings.
- safedata::mysqli_escape_string (string/array, reference mysqli)
An object-oriented mysqli_real_escape_string() wrapper for
both strings and arrays that contain strings.

HTML-Safe Functions
- safedata::htmlentities (string/array, optional quote_style, optional charset)
- safedata::htmlspecialchars (string/array, optional quote_style, optional charset)
A wrapper for htmlentities() and htmlspecialchars() that takes
both strings and arrays containing strings.
- [LEGACY] safedata::htmlentities_array
alias of safedata::htmlentities()
- [LEGACY] safedata::htmlspecialchars_array
alias of safedata::htmlspecialchars()

Form Validation Functions
- safedata::is_int (form_variable)
Tests if the form variable is a valid integer.
- safedata::is_float (form_variable)
Tests if the form variable is a valid float.
- safedata::is_string (form_variable)
Tests if the form variable is a valid string.
- safedata::gettype (form_variable)
Returns the form variable's type.
('int', 'float', 'string', 'array', 'unknown')

How to use:
To automatically disable register_globals and magic_quotes, and enable the
use of safedata's helpful functions, simply include this class file at the
top of your script. For example:
require_once('safedata.class.php');

Then, you can use the methods of this class either statically:
$_POST = safedata::mysqli_escape_string ($_POST, &$mysqli);
or through an instantiated object:
$safedata = new safedata();
$_POST = $safedata->mysqli_escape_string ($_POST, &$mysqli);

Credits:
Created by Matt Smith and released under the BSD (3-clause) license --
this class is based on:

- The articles at the PHP Security Consortium
http://phpsec.org
- This ONLamp.com article, entitled "PHP Form Handling"
http://www.onlamp.com/pub/a/php/2004/08/26/PHPformhandling.html
- This NYPHP article
http://education.nyphp.org/phundamentals/PH_storingretrieving.php
- and PHP function comments at
http://php.net

*/

class safedata
{
// Private/Internal Functions

function __init ()
{
safedata::__disable_register_globals ();
safedata::__disable_magic_quotes ();

$phpversion = phpversion ();
$GLOBALS['__safedata__']['php4'] = version_compare ($phpversion, "5.0.0", "lt");
$GLOBALS['__safedata__']['php420'] = version_compare ($phpversion, "4.2.0", "ge");
$GLOBALS['__safedata__']['php430'] = version_compare ($phpversion, "4.3.0", "lt");
$GLOBALS['__safedata__']['version'] = '1.0';
$GLOBALS['__safedata__']['release'] = array ('month' => 10, 'day' => 17, 'year' => 2005);
}

// This gives the current version of the safedata class.
function __version ()
{
return $GLOBALS['__safedata__']['version'];
}

// This gives the release date of this version.
function __release ($datefmt = 'F d, Y')
{
extract ($GLOBALS['__safedata__']['release']);
return date ($datefmt, mktime (0, 0, 0, $month, $day, $year) );
}

// A function to fix register_globals
function __disable_register_globals ()
{
if ( ini_get ('register_globals') )
{
foreach ( array ('_ENV', '_REQUEST', '_GET', '_POST', '_COOKIE', '_SERVER') as $globalkey )
foreach ( $GLOBALS[$globalkey] as $sub_globalkey => $sub_globalval )
if ( isset ($GLOBALS[$sub_globalkey]) )
{
if ( $GLOBALS['__safedata__']['php4'] ) // PHP 4
$unset_line = "if ( !is_a (\$GLOBALS[\$sub_globalkey], 'safedata') ) { unset (\$GLOBALS[\$sub_globalkey]); }";
else // PHP 5
$unset_line = "if ( !(\$GLOBALS[\$sub_globalkey] instanceof safedata) ) { unset (\$GLOBALS[\$sub_globalkey]); }";
eval ($unset_line);
}

ini_set ('register_globals', 0);
}
}

// NYPHP's fix_magic_quotes function
// http://education.nyphp.org/phundamentals/PH_storingretrieving.php
function __disable_magic_quotes ($var = NULL, $sybase = NULL)
{
// if sybase style quoting isn't specified, use ini setting
if ( !isset ($sybase) )
{
$sybase = ini_get ('magic_quotes_sybase');
}

// if no var is specified, fix all affected superglobals
if ( !isset ($var) )
{
// if magic quotes is enabled
if ( get_magic_quotes_gpc () )
{
// workaround because magic_quotes does not change $_SERVER['argv']
$argv = isset($_SERVER['argv']) ? $_SERVER['argv'] : NULL;

// fix all affected arrays
foreach ( array ('_ENV', '_REQUEST', '_GET', '_POST', '_COOKIE', '_SERVER') as $var )
{
$GLOBALS[$var] = safedata::__disable_magic_quotes ($GLOBALS[$var], $sybase);
}

$_SERVER['argv'] = $argv;

// turn off magic quotes, this is so scripts which
// are sensitive to the setting will work correctly
ini_set ('magic_quotes_gpc', 0);
}

// disable magic_quotes_sybase
if ( $sybase )
{
ini_set ('magic_quotes_sybase', 0);
}

// disable magic_quotes_runtime
set_magic_quotes_runtime (0);
return TRUE;
}

// if var is an array, fix each element
if ( is_array ($var) )
{
foreach ( $var as $key => $val )
{
$var[$key] = safedata::__disable_magic_quotes ($val, $sybase);
}

return $var;
}

// if var is a string, strip slashes
if ( is_string ($var) )
{
return $sybase ? str_replace ('\'\'', '\'', $var) : stripslashes ($var);
}

// otherwise ignore
return $var;
}

// SQL-Safe Functions

// A mysql_[real_]escape_string() wrapper for both strings and arrays.
function mysql_escape_string ($var, $link_id = NULL)
{
if ( is_array ($var) )
{
foreach ($var as $key => $val)
$var[$key] = safedata::mysql_escape_string ($val, $link_id);
}
else
{
if ( !is_numeric ($var) )
{
if ( $GLOBALS['__safedata__']['php430'] )
return mysql_escape_string ($var);
else
return isset ($link_id) ? mysql_real_escape_string ($var, $link_id) : mysql_real_escape_string ($var);
}
}

return $var;
}

// An object-oriented mysqli_real_escape_string() wrapper for
// both strings and arrays.
function mysqli_escape_string ($var, $mysqli)
{
if ( is_array ($var) )
{
foreach ($var as $key => $val)
$var[$key] = safedata::mysqli_escape_string ($val, $mysqli);
}
else
{
if ( !is_numeric ($var) )
return $mysqli->real_escape_string ($var);
}

return $var;
}

// HTML-Safe Functions

// An htmlentities() wrapper for both strings and arrays.
function htmlentities ($var, $quote_style = ENT_COMPAT, $charset = 'ISO-8859-1')
{
if ( is_array ($var) )
{
foreach ($var as $key => $val)
$var[$key] = safedata::htmlentities ($val, $quote_style, $charset);
}
else
{
if ( !is_numeric ($var) )
return htmlentities ($var, $quote_style, $charset);
}

return $var;
}
// Legacy
function htmlentities_array ($var, $quote_style = ENT_COMPAT, $charset = 'ISO-8859-1')
{
return safedata::htmlentities ($var, $quote_style, $charset);
}

// An htmlspecialchars() wrapper for both strings and arrays.
function htmlspecialchars ($var, $quote_style = ENT_COMPAT, $charset = 'ISO-8859-1')
{
if ( is_array ($var) )
{
foreach ($var as $key => $val)
$var[$key] = safedata::htmlspecialchars ($val, $quote_style, $charset);
}
else
{
if ( !is_numeric ($var) )
return htmlspecialchars ($var, $quote_style, $charset);
}

return $var;
}
// Legacy
function htmlspecialchars_array ($var, $quote_style = ENT_COMPAT, $charset = 'ISO-8859-1')
{
return safedata::htmlspecialchars ($var, $quote_style, $charset);
}

// Form Validation Functions

// Tests for integer.
function is_int ($var)
{
if ( is_array ($var) || is_object ($var) )
return false;

return ( $var == strval (intval ($var) ) ) ? true : false;
}

// Tests for float.
function is_float ($var)
{
if ( is_array ($var) || is_object ($var) )
return false;

if ( $GLOBALS['__safedata__']['php420'] )
return ( $var == strval (floatval ($var) ) ) ? true : false;
else
return ( $var == strval (doubleval ($var) ) ) ? true : false;
}

// Tests for string.
function is_string ($var)
{
if ( is_array ($var) || is_object ($var) )
return false;

return ( $var == strval ($var) ) ? true : false;
}

// Tests for variable type and returns it's type:
// 'int', 'float, 'string', 'array', or 'unknown'
function gettype ($var)
{
if ( safedata::is_int ($var) )
return 'int';
elseif ( safedata::is_float ($var) )
return 'float';
elseif ( safedata::is_string ($var) )
return 'string';
elseif ( is_array ($var) )
return 'array';
else
return 'unknown';
}

}

// Initialize safedata
safedata::__init ();


[/PHP]

کلاس capcha یا آنتی اسپم:

[PHP]
class captchaZDR {

var $UserString;
var $font_path;

function captchaZDR(){
switch(rand(1,11))
{
case 1 : $this->font_path = '../images/fonts/architextregular.ttf'; break;
case 2 : $this->font_path = '../images/fonts/ASTUTEI.ttf'; break;
case 3 : $this->font_path = '../images/fonts/augie.ttf'; break;
case 4 : $this->font_path = '../images/fonts/BASSETI.ttf'; break;
case 5 : $this->font_path = '../images/fonts/BITMAP.ttf'; break;
case 6 : $this->font_path = '../images/fonts/BITMAPW.ttf'; break;
case 7 : $this->font_path = '../images/fonts/BOLSTER.ttf'; break;
case 8 : $this->font_path = '../images/fonts/font.ttf'; break;
case 9 : $this->font_path = '../images/fonts/freesans.ttf'; break;
case 10 : $this->font_path = '../images/fonts/lockergnome.ttf'; break;
case 11 : $this->font_path = '../images/fonts/mrph.ttf'; break;
default : $this->font_path = '../images/fonts/font.ttf'; break;
}
}

function LoadPNG(){
$bgNUM = rand(1,8);
$im = @imagecreatefrompng('../images/captcha_bank/bg'.$bgNUM.'.png'); /* Attempt to open */
if (!$im) {
$im = imagecreatetruecolor(150, 30); /* Create a blank image */
$bgc = imagecolorallocate($im, 255, 255, 255);
$tc = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 150, 30, $bgc);
imagestring($im, 1, 5, 5, "Error loading $imgname", $tc);
}
return $im;
}

function drawElipse($image){
for($i=0;$i<5;$i++){
// choose a color for the ellipse
$red = rand(0,155);
$green = rand(0,155);
$blue = rand(0,155);
$col_ellipse = imagecolorallocate($image, $red, $green, $blue);
// draw the ellipse
$cx = rand(50,250);
$cy = rand(50,250);
$cw = rand(30,250);
$ch = rand(20,250);
imageellipse($image, $cx, $cy, $cw, $ch, $col_ellipse);
}

foreach (range('A', 'Z') as $letter) {
$red = rand(0,155);
$green = rand(0,155);
$blue = rand(0,155);
$col_ellipse = imagecolorallocate($image, $red, $green, $blue);
$font_size = 2; //rand(1,12);
$x = rand(0,400);
$y = rand(0,200);
imagechar($image, $font_size, $x, $y, $letter, $col_ellipse);
}

foreach (range('0', '9') as $letter) {
$red = rand(0,155);
$green = rand(0,155);
$blue = rand(0,155);
$col_ellipse = imagecolorallocate($image, $red, $green, $blue);
$font_size = 2;
$x = rand(0,200);
$y = rand(0,100);
imagechar($image, $font_size, $x, $y, $letter, $col_ellipse);
}

}

function task_string(){

// create a image from png bank
$image = $this->LoadPNG();

$string_a = array("A","B","C","D","E","F","G","H","J","K",
"L","M","N","P","R","S","T","U","V","W","X","Y","Z ",
"2","3","4","5","6","7","8","9");

$width = 0;
for($i=0;$i<5;$i++)
{
$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$font = $this->font_path;
$angle = rand(-15,15);
// Add the text
$width_pos = rand(20,30);
$width = $width + $width_pos;
$height = rand(35,75);
$temp = $string_a[rand(0,25)];
$this->UserString .= $temp;
imagettftext($image, 26, $angle, $width, $height, $colour, $font, $temp);
$width = $width + 3;
$height = $height + 3;
imagettftext($image, 26, $angle, $width, $height, $colour, $font, $temp);

}

$_SESSION['captcha'] = $this->UserString;

return $image;
}

function task_sum(){
// create a image from png bank
$image = $this->LoadPNG();

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$font = $this->font_path;
$angle = rand(-15,15);
// Add the text
$width = rand(20,30);
$height = rand(35,75);

$number1 = rand(1,99);
$number2 = rand(1,9);


imagettftext($image, 26, $angle, $width, $height, $colour, $font, $number1);

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$width += 45;
imagettftext($image, 26, 0, $width, $height, $colour, $font, '+');

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$width += 25;
$angle = rand(-15,15);
imagettftext($image, 26, $angle, $width, $height, $colour, $font, $number2.'=?');

$this->UserString = $number1+$number2;

$_SESSION['captcha'] = $this->UserString;

return $image;
}

function task_deduction(){
// create a image from png bank
$image = $this->LoadPNG();

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$font = $this->font_path;
$angle = rand(-15,15);
// Add the text
$width = rand(20,30);
$height = rand(35,75);

$number1 = rand(1,99);
$number2 = rand(1,9);

imagettftext($image, 26, $angle, $width, $height, $colour, $font, $number1);

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$width += 45;
imagettftext($image, 26, 0, $width, $height, $colour, $font, '-');

$colour = imagecolorallocate($image, rand(0,155), rand(0,155), rand(0,155));
$width += 25;
$angle = rand(-15,15);
imagettftext($image, 26, $angle, $width, $height, $colour, $font, $number2.'=?');

$this->UserString = $number1-$number2;

$_SESSION['captcha'] = $this->UserString;

return $image;
}

function display(){

switch(rand(1,3))
{
case 1 : $image = $this->task_string(); break;
case 2 : $image = $this->task_sum(); break;
case 3 : $image = $this->task_deduction(); break;

default : $image = $this->task_string(); break;
}

$this->drawElipse($image);

// output the picture
header("Content-type: image/png");
imagepng($image);
}

function check_result(){
if($_SESSION['captcha']!=$_REQUEST['capt'] || $_SESSION['captcha']=='BADCODE')
{
$_SESSION['captcha']='BADCODE';
return false;
}
else
{
return true;
}
}

}


[/PHP]

نحوه استفاده:
[PHP]
$captcha = new captchaZDR();

$captcha->display();
[/PHP]

نحوه چک کردن:
[PHP]
if(!$captcha->check_result()){
$errors[] = $plang['err_antisam_captcha'];
}
[/PHP]

البته باید بک گراندها و فونت هارو هم داشته باشید تا کار کنه!

دوستان اگه بهتر می تونن. ادامه بدن

یه تابع کاملتر برای چک کردن ورودی ها نوشتم که میتونید از این استفاده کنید . این کاملتره به نظرم:
[PHP]
function filter_html($what){


///.. BASIC ASCII Entities with new Entity Names
$what = str_replace( "&#" , "(^)-(^)" , $what );
$what = str_replace( "&" , "&amp;" , $what );
$what = str_replace( ">" , "&gt;" , $what );
$what = str_replace( "<" , "&lt;" , $what );
$what = ereg_replace( "\"" , "&quot;" , $what );
$what = str_replace( "!" , "!" , $what );
$what = str_replace( "'" , "'" , $what );
$what = str_replace( "(^)-(^)" , "&#" , $what );
$what = str_replace("`" ,"" , $what );
$what = ereg_replace("\n" , "<br>" , $what );
$what = ereg_replace("\r" , "" , $what );

///.. ISO 8859-1 Symbol Entities
$what = str_replace("¡" , "&iexcl;" , $what );
$what = str_replace("¤" , "&curren;" , $what );
$what = str_replace("¢" , "&cent;" , $what );
$what = str_replace("£" , "&pound;" , $what );
$what = str_replace("€" , "&euro;" , $what );
$what = str_replace("¥" , "&yen;" , $what );
$what = str_replace("¦" , "&brvbar;" , $what );
$what = str_replace("§" , "&sect;" , $what );
$what = str_replace("©" , "&copy;" , $what );
$what = str_replace("¿" , "&iquest;" , $what );
$what = str_replace("¶" , "&para;" , $what );

///.. ISO 8859-1 Character Entities
$what = str_replace("À" , "&Agrave;" , $what );
$what = str_replace("Á" , "&Aacute;" , $what );
$what = str_replace("Â" , "&Acirc;" , $what );
$what = str_replace("Ä" , "&Auml;" , $what );
$what = str_replace("Å" , "&Aring;" , $what );
$what = str_replace("Æ" , "&AElig;" , $what );
$what = str_replace("Ç" , "&Ccedil;" , $what );
$what = str_replace("È" , "&Egrave;" , $what );
$what = str_replace("É" , "&Eacute;" , $what );
$what = str_replace("Ê" , "&Ecirc;" , $what );
$what = str_replace("Ë" , "&Euml;" , $what );
$what = str_replace("Ì" , "&Igrave;" , $what );
$what = str_replace("Î" , "&Icirc;" , $what );
$what = str_replace("Ï" , "&Iuml;" , $what );
$what = str_replace("Ð" , "&ETH;" , $what );
$what = str_replace("Ñ" , "&Ntilde;" , $what );
$what = str_replace("Ò" , "&Ograve;" , $what );
$what = str_replace("Ó" , "&Oacute;" , $what );
$what = str_replace("Ô" , "&Ocirc;" , $what );
$what = str_replace("Õ" , "&Otilde;" , $what );
$what = str_replace("Ö" , "&Ouml;" , $what );
$what = str_replace("Ø" , "&Oslash;" , $what );
$what = str_replace("Ù" , "&Ugrave;" , $what );
$what = str_replace("Ú" , "&Uacute;" , $what );
$what = str_replace("Û" , "&Ucirc;" , $what );
$what = str_replace("Ü" , "&Uuml;" , $what );
$what = str_replace("Ý" , "&Yacute;" , $what );
$what = str_replace("Þ" , "&THORN;" , $what );
$what = str_replace("ß" , "&szlig;" , $what );
$what = str_replace("à" , "&agrave;" , $what );
$what = str_replace("á" , "&aacute;" , $what );
$what = str_replace("â" , "&acirc;" , $what );
$what = str_replace("à" , "&aacute;" , $what );
$what = str_replace("ä" , "&auml;" , $what );
$what = str_replace("å" , "&aring;" , $what );
$what = str_replace("æ" , "&aelig;" , $what );
$what = str_replace("ç" , "&ccedil;" , $what );
$what = str_replace("è" , "&egrave;" , $what );
$what = str_replace("é" , "&eacute;" , $what );
$what = str_replace("ê" , "&ecirc;" , $what );
$what = str_replace("ë" , "&euml;" , $what );
$what = str_replace("ì" , "&igrave;" , $what );
$what = str_replace("í" , "&iacute;" , $what );
$what = str_replace("î" , "&icirc;" , $what );
$what = str_replace("ï" , "&iuml;" , $what );
$what = str_replace("ð" , "&eth;" , $what );
$what = str_replace("ñ" , "&ntilde;" , $what );
$what = str_replace("ò" , "&ograve;" , $what );
$what = str_replace("ó" , "&oacute;" , $what );
$what = str_replace("ô" , "&ocirc;" , $what );
$what = str_replace("õ" , "&otilde;" , $what );
$what = str_replace("ö" , "&ouml;" , $what );
$what = str_replace("ø" , "&oslash;" , $what );
$what = str_replace("ù" , "&ugrave;" , $what );
$what = str_replace("ú" , "&uacute;" , $what );
$what = str_replace("û" , "&ucirc;" , $what );
$what = str_replace("ü" , "&uuml;" , $what );
$what = str_replace("ý" , "&yacute;" , $what );
$what = str_replace("þ" , "&thorn;" , $what );
$what = str_replace("ÿ" , "&yuml;" , $what );

///.. ISO 8859-1 Other Entities
$what = str_replace("Œ" , "&OElig;" , $what );
$what = str_replace("œ" , "&oelig;" , $what );
$what = str_replace("Š" , "&Scaron;" , $what );
$what = str_replace("š" , "&scaron;" , $what );
$what = str_replace("˜" , "&tilde;" , $what );
$what = str_replace("‘" , "&lsquo;" , $what );
$what = str_replace("’" , "&rsquo;" , $what );
$what = str_replace("‚" , "&sbquo;" , $what );

// for some really strange reason this is replacing all characters:
$what = str_replace("Ã" , "&Atilde;" , $what );
$what = str_replace("ã" , "&atilde;" , $what );

return $what;
}

[/PHP]

و در ضمن تابع زیر رو زمانی میشه بکار برد که به ورودی اجازه کدهای html رو میدیم ولی اجازه ورود تگ های حساس رو منع می کنیم:
[PHP]
function filter_html_dangerous_tags($what){
$what = str_replace( "<script>" , "&lt;script&gt;" , $what );
$what = str_replace( "</script>" , "&lt;/script&gt;" , $what );
$what = str_replace( "<object>" , "&lt;object&gt;" , $what );
$what = str_replace( "</object>" , "&lt;/object&gt;" , $what );
$what = str_replace( "<iframe>" , "&lt;iframe&gt;" , $what );
$what = str_replace( "</iframe>" , "&lt;/iframe&gt;" , $what );
$what = str_replace( "<frameset>" , "&lt;frameset&gt;" , $what );
$what = str_replace( "<frameset>" , "&lt;frameset&gt;" , $what );
$what = str_replace( "<frame>" , "&lt;frame&gt;" , $what );
$what = str_replace( "</frame>" , "&lt;/frame&gt;" , $what );
$what = str_replace( "<link>" , "&lt;link&gt;" , $what );
$what = str_replace( "</link>" , "&lt;/link&gt;" , $what );
return $what;
}

[/PHP]

سلام
چطوری میشه از این کدا استفاده کرد و در چه مواقعی
البته ببخشید اگه خیلی مبتدی هست سوالم

اگر میشه نحوه استفاده از این کدها رو هم توضیح بدید. الان من نمی دونم این کدهارو کجا کپی کنم تا سایتم اینهارو استفاده کنه...
ممنون