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Homephp教程php手册PHP魔术引号所带来的安全问题分析,魔术引号

PHP魔术引号所带来的安全问题分析,魔术引号

PHP通过提取魔术引号产生的“\”字符会带来一定的安全问题,例如下面这段代码片段:

// foo.php?xigr='ryat
function daddslashes($string, $force = 0) {
!defined('MAGIC_QUOTES_GPC') && define('MAGIC_QUOTES_GPC', get_magic_quotes_gpc());
if(!MAGIC_QUOTES_GPC || $force) {
if(is_array($string)) {
foreach($string as $key => $val) {
$string[$key] = daddslashes($val, $force);
}
} else {
$string = addslashes($string);
}
}
return $string;
}
...
foreach(array('_COOKIE', '_POST', '_GET') as $_request) {
foreach($$_request as $_key => $_value) {
$_key{0} != '_' && $$_key = daddslashes($_value);
}
}
echo $xigr['hi'];
// echo \

上面的代码原本期望得到一个经过daddslashes()安全处理后的数组变量$xigr['hi'],但是没有对变量$xigr做严格的类型规定,当我们提交一个字符串变量$xigr='ryat,经过上面的处理变为\'ryat,到最后$xigr['hi']就会输出\,如果这个变量引入到SQL语句,那么就会引起严重的安全问题了,对此再来看下面的代码片段:

...
if($xigr) {
foreach($xigr as $k => $v) {
$uids[] = $v['uid'];
}
$query = $db->query("SELECT uid FROM users WHERE uid IN ('".implode("','", $uids)."')");

利用上面提到的思路,通过提交foo.php?xigr[]='&xigr[][uid]=evilcode这样的构造形式可以很容易的突破GPC或类似的安全处理,形成SQL注射漏洞!对此应给与足够的重视!

[php学习]教1个魔术引号修正函数

多谢,基本理解了,这个函数的作用应该是:如果魔术引号功能打开,就把它添加的反斜线去掉,再根据情况自己用addslashes()或mysql_real_escape_string()来处理。
 

thinkphp 对于php魔术引号 我只要上传 带连接的 或者是 图片 之类的 就给我自动加一个 “ / ” 解决

我想确定一下,你传过来的值加的是"/"吗,如果是"/",你可以尝试在Action中把"/"替换成空。
以前我传过来的值加的是"\",所以我当初是用的stripslashes($_POST['ck'])来搞定的。
 

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