PHP 过滤表单提交特殊字符（防注入)

$dbstr='D:test
<a href="http://www.111cn.net">http://www.111cn.net</a>,天缘博客
'!='1' OR '1'
</DIV>
<script  language="javascript" type="text/javascript">alert("Fail");</script>

<?php echo "<br/>PHP OUTPUT"; ?>';

 header("Content-Type: text/html; charset=UTF-8");
echo "------------------------------------------------------<br/>rn";
echo  $dbstr."<br/>rn------------------------------------------------------<br/>rn";
$str=fnAddSlashes($_POST['dd']);
echo $str."<br/>rn------------------------------------------------------<br/>rn";

$str = preg_replace("/s(?=s)/","\1",$str);//多个连续空格只保留一个
$str = str_replace("r","<br/>",$str);
$str = str_replace("n","<br/>",$str);
$str = preg_replace("/((<br/?>)+)/i", "<br/>", $str);//多个连续<br/>标签只保留一个

$str=stripslashes($str);
echo strip_tags($str)."<br/>rn------------------------------------------------------<br/>rn";
echo htmlspecialchars($str)."<br/>rn------------------------------------------------------<br/>rn";
echo htmlentities($str)."<br/>rn------------------------------------------------------<br/>rn";
echo mysql_escape_string($str)."<br/>rn------------------------------------------------------<br/>rn";

function fnAddSlashes($data)
{
    if(!get_magic_quotes_gpc()) //只对POST/GET/cookie过来的数据增加转义
        return is_array($data)?array_map('addslashes',$data):addslashes($data);
    else
        return $data;
}

$data = preg_replace("/s(?=s)/","\1",$data );//多个连续空格只保留一个

function fnEscapeStr($data)

{

if (get_magic_quotes_gpc())
{
        $data= stripslashes($value);
}
$data="'". mysql_escape_string($value) ."'";
return $data;
}

$data=fnEscapeStr($data);

<?php
session_start();
$k=$_GET['k'];
$t=$_GET['t'];
$allowTime = 1800;//防刷新时间
$ip = get_client_ip();
$allowT = md5($ip.$k.$t);
if(!isset($_SESSION[$allowT]))
{
$refresh = true;
$_SESSION[$allowT] = time();
}elseif(time() - $_SESSION[$allowT]>$allowTime){
$refresh = true;
$_SESSION[$allowT] = time();
}else{
$refresh = false;
}
?>

if(isset($_POST))
{ 
if(变量不符合要求)
<script> history.go(-1); </script>
else
操作数据
...
if(操作完成)
header( "location: ".$_SERVER[ 'PHP_SELF ']);
}
<script language= "JavaScript ">
<!--
　javascript:window.history.forward(1);
//-->
</script>

<?php
$c_file="counter.txt"; //文件名赋值给变量
if(!file_exists($c_file)) //如果文件不存在的操作
{
$myfile=fopen($c_file,"w"); //创建文件
fwrite($myfile,"0"); //置入“0”
fclose($myfile); //关闭文件
}
$t_num=file($c_file); //把文件内容读入变量
if($_COOKIE["date"]!="date(Y年m月d日)") //判断COOKIE内容与当前日期是否一致
{
$t_num[0]++; //原始数据自增1
$myfile=fopen($c_file,"w"); //写入方式打开文件
fwrite($myfile,$t_num[0]); //写入新数值
fclose($myfile); //关闭文件
//重新将当前日期写入COOKIE并设定COOKIE的有效期为24小时
setcookie("date","date(Y年m月d日)",time()+60*60*24);
}
?>

if (!get_magic_quotes_gpc()) {

　　$lastname = addslashes($_POST[‘lastname’]);

　　} else {

　　$lastname = $_POST[‘lastname’];

}

$sql = "select count(*) as ctr from users where username02.='".mysql_real_escape_string($username)."' and 03.password='". mysql_real_escape_string($pw)."' limit 1";

function inject_check($sql_str) {
    return eregi('select|insert|and|or|update|delete|'|/*|*|../|./|union|into|load_file|outfile', $sql_str);
}
 
function verify_id($id=null) {
    if(!$id) {
        exit('没有提交参数！');
    } elseif(inject_check($id)) {
        exit('提交的参数非法！');
    } elseif(!is_numeric($id)) {
        exit('提交的参数非法！');
    }
    $id = intval($id);
    
    return $id;
}
 
 
function str_check( $str ) {
    if(!get_magic_quotes_gpc()) {
        $str = addslashes($str); // 进行过滤
    }
    $str = str_replace("_", "_", $str);
    $str = str_replace("%", "%", $str);
    
   return $str;
}
 
 
function post_check($post) {
    if(!get_magic_quotes_gpc()) {
        $post = addslashes($post);
    }
    $post = str_replace("_", "_", $post);
    $post = str_replace("%", "%", $post);
    $post = nl2br($post);
    $post = htmlspecialchars($post);
    
    return $post;
}

function _code($_code_length = 4, $_width = 75, $_height = 25){
    for($i=0;$i<$_code_length;$i++){
        $_nmsg .= dechex(mt_rand(0,15));
    }
    $_SESSION["code"] = $_nmsg;

    $_img = imagecreatetruecolor($_width, $_height);

    $_white = imagecolorallocate($_img, 250, 250, 250);

    imagefill($_img, 0, 0, $_white);

    $_gray = imagecolorallocate($_img, 196, 196, 196);

    imagerectangle($_img, 0, 0, $_width-1, $_height-1, $_gray);

    for ($i=0; $i < 6; $i++) {
        $_md_color = imagecolorallocate($_img, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));
        imageline($_img, mt_rand(0,$_width), mt_rand(0, $_height),mt_rand(0,$_width), mt_rand(0, $_height), $_md_color);
    }

    for ($i=0; $i < 50; $i++) {
        $_md_color = imagecolorallocate($_img, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));
        imagestring($_img, 1, mt_rand(1,$_width-5), mt_rand(1, $_height-5), "*", $_md_color);
    }

    for ($i=0; $i < $_code_length ; $i++) {
        $_md_color = imagecolorallocate($_img, mt_rand(0,102), mt_rand(0,102), mt_rand(0,102));
        imagestring($_img, 5, $i * $_width/$_code_length+ mt_rand(1, 10), mt_rand(1, $_height/2), $_SESSION["code"][$i], $_md_color);
    }

    header("Content-Type:image/png");

    imagepng($_img);

    imagedestroy($_img);
}

$getcode = $_POST['code'];

if( $_SESSION["code"] = $getcode )
{
  echo ' 验证合法，进入下一步';
  unset( $_SESSION["code"] );
}
else
{
  echo ' 验证码不正确';
  header('location:vial.php');
}

<?php 
session_start();
//设置: 你可以在这里修改验证码图片的参数
$image_width = 120;
$image_height = 40;
$characters_on_image = 6;
$font = './monofont.ttf'; 
 
//以下字符将用于验证码中的字符 
//为了避免混淆去掉了数字1和字母i
$possible_letters = '23456789bcdfghjkmnpqrstvwxyz';
$random_dots = 10;
$random_lines = 30;
$captcha_text_color="0x142864";
$captcha_noice_color = "0x142864"; 
 
$code = ''; 
 
$i = 0;
while ($i < $characters_on_image) { 
    $code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1);
    $i++;
}
 
$font_size = $image_height * 0.75; 
$image = @imagecreate($image_width, $image_height);
 
/* 设置背景、文本和干扰的噪点 */
$background_color = imagecolorallocate($image, 255, 255, 255);
 
$arr_text_color = hexrgb($captcha_text_color); 
$text_color = imagecolorallocate($image, $arr_text_color['red'], 
$arr_text_color['green'], $arr_text_color['blue']);
 
$arr_noice_color = hexrgb($captcha_noice_color); 
$image_noise_color = imagecolorallocate($image, $arr_noice_color['red'], 
$arr_noice_color['green'], $arr_noice_color['blue']);
 
/* 在背景上随机的生成干扰噪点 */
for( $i=0; $i<$random_dots; $i++ ) {
    imagefilledellipse($image, mt_rand(0,$image_width),
    mt_rand(0,$image_height), 2, 3, $image_noise_color);
}
 
/* 在背景图片上，随机生成线条 */
for( $i=0; $i<$random_lines; $i++ ) {
    imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height),
    mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color);
}
 
/* 生成一个文本框，然后在里面写生6个字符 */
$textbox = imagettfbbox($font_size, 0, $font, $code); 
$x = ($image_width - $textbox[4])/2;
$y = ($image_height - $textbox[5])/2;
imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);
 
/* 将验证码图片在HTML页面上显示出来 */
header('Content-Type: image/jpeg');
// 设定图片输出的类型
imagejpeg($image);
//显示图片
imagedestroy($image);
//销毁图片实例
$_SESSION['6_letters_code'] = $code;
 
function hexrgb ($hexstr) {
    $int = hexdec($hexstr);
 
    return array( "red" => 0xFF & ($int >> 0x10),
                "green" => 0xFF & ($int >> 0x8),
                "blue" => 0xFF & $int
    );
}
?>

验证码

<p>验证码：<input type="text" class="input" id="code_num" name="code_num" maxlength="4" />  
<img src="code_num.php" id="getcode_num" title="看不清，点击换一张" align="absmiddle"></p> 
<p><input type="button" class="btn" id="chk_num" value="提交" /></p> 

$(function(){ 
    //数字验证 
    $("#getcode_num").click(function(){ 
        $(this).attr("src",'code_num.php?' + Math.random()); 
    }); 
    ... 
}); 

$(function(){ 
    ... 
    $("#chk_num").click(function(){ 
        var code_num = $("#code_num").val(); 
        $.post("chk_code.php?act=num",{code:code_num},function(msg){ 
            if(msg==1){ 
                alert("验证码正确！"); 
            }else{ 
                alert("验证码错误！"); 
            } 
        }); 
    }); 
}); 

session_start(); 
 
$code = trim($_POST['code']); 
if($code==$_SESSION["helloweba_num"]){ 
   echo '1'; 
}