web程序在显示数据时候一定要转义

[下载]php java javascript 相关 api 手册的下载

防止web的注入漏洞，当然是要处理用户输入的（这个不谈了）

但是千万不要忘记数据显示的时候，也要处理一下，比如htmlspecialchars 一下所有的数据再显示，否则依然会被hack的
可以参考一下smarty的escape函数，看看人家怎么做的转义，这样转义之后显示数据，肯定是安全的了

function smarty_modifier_escape($string, $esc_type = 'html', $char_set = 'ISO-8859-1')
{
    switch ($esc_type) {
        case 'html':
            return htmlspecialchars($string, ENT_QUOTES, $char_set);

        case 'htmlall':
            return htmlentities($string, ENT_QUOTES, $char_set);

        case 'url':
            return rawurlencode($string);

        case 'urlpathinfo':
            return str_replace('%2F','/',rawurlencode($string));
           
        case 'quotes':
            // escape unescaped single quotes
            return preg_replace("%(?<!\\\\)'%", "\\'", $string);

        case 'hex':
            // escape every character into hex
            $return = '';
            for ($x=0; $x < strlen($string); $x++) {
                $return .= '%' . bin2hex($string[$x]);
            }
            return $return;
           
        case 'hexentity':
            $return = '';
            for ($x=0; $x < strlen($string); $x++) {
                $return .= '&#x' . bin2hex($string[$x]) . ';';
            }
            return $return;

        case 'decentity':
            $return = '';
            for ($x=0; $x < strlen($string); $x++) {
                $return .= '&#' . ord($string[$x]) . ';';
            }
            return $return;

        case 'javascript':
            // escape quotes and backslashes, newlines, etc.
            return strtr($string, array('\\'=>'\\\\',"'"=>"\\'",'"'=>'\\"',"\r"=>'\\r',"\n"=>'\\n','</'=>'<\/'));
           
        case 'mail':
            // safe way to display e-mail address on a web page
            return str_replace(array('@', '.'),array(' [AT] ', ' [DOT] '), $string);
           
        case 'nonstd':
           // escape non-standard chars, such as ms document quotes
           $_res = '';
           for($_i = 0, $_len = strlen($string); $_i < $_len; $_i++) {
               $_ord = ord(substr($string, $_i, 1));
               // non-standard char, escape it
               if($_ord >= 126){
                   $_res .= '&#' . $_ord . ';';
               }
               else {
                   $_res .= substr($string, $_i, 1);
               }
           }
           return $_res;

        default:
            return $string;
    }
}

Tags: