在网站中表单提交或url获取值我们都可能碰到一些安全问题,下面我总结了一些常用的过滤一些危险特殊字符的解决方法,一般,对于传进来的字符，php可以用addslashes函数处理一遍（要get_magic_quotes_gpc()为假才处理，不然就重复转义了！），这样就能达到一定程度的安全要求,比如这样,代码如下:
if (!get_magic_quotes_gpc()) {
add_slashes($_GET);
add_slashes($_POST);
add_slashes($_COOKIE);
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}
function add_slashes($string) {
if (is_array($string)) {
foreach ($string as $key => $value) {
$string[$key] = add_slashes($value);
}
} else {
$string = addslashes($string);
}
return $string;
}
但是还可以更进一步进行重新编码,解码,代码如下:
//编码
function htmlencode($str) {
if(emptyempty($str)) return;
if($str=="") return $str;
$str=trim($str);
$str=str_replace("&","&",$str);
$str=str_replace("youjiankuohaophpcn",">",$str);
$str=str_replace("zuojiankuohaophpcn","
$str=str_replace(chr(32)," ",$str);
$str=str_replace(chr(9)," ",$str);
$str=str_replace(chr(34),"&",$str);
$str=str_replace(chr(39),"'",$str);
$str=str_replace(chr(13),"zuojiankuohaophpcnbr /youjiankuohaophpcn",$str);
$str=str_replace("'","''",$str);
$str=str_replace("select","select",$str);
$str=str_replace("join","join",$str);
$str=str_replace("union","union",$str);
$str=str_replace("where","where",$str);
$str=str_replace("insert","insert",$str);
$str=str_replace("delete","delete",$str);
$str=str_replace("update","update",$str);
$str=str_replace("like","like",$str);
$str=str_replace("drop","drop",$str);
$str=str_replace("create","create",$str);
$str=str_replace("modify","modify",$str);
$str=str_replace("rename","rename",$str);
$str=str_replace("alter","alter",$str);
$str=str_replace("cast","cas",$str);
return $str;
}
这样就能更放心的对外来数据进行入库处理了,但是从数据库取出来,在前台显示的时候,必须重新解码一下,代码如下:
//解码
function htmldecode($str) {
if(emptyempty($str)) return;
if($str=="") return $str;
$str=str_replace("select","select",$str);
$str=str_replace("join","join",$str);
$str=str_replace("union","union",$str);
$str=str_replace("where","where",$str);
$str=str_replace("insert","insert",$str);
$str=str_replace("delete","delete",$str);
$str=str_replace("update","update",$str);
$str=str_replace("like","like",$str);
$str=str_replace("drop","drop",$str);
$str=str_replace("create","create",$str);
$str=str_replace("modify","modify",$str);
$str=str_replace("rename","rename",$str);
$str=str_replace("alter","alter",$str);
$str=str_replace("cas","cast",$str);
$str=str_replace("&","&",$str);
$str=str_replace(">","youjiankuohaophpcn",$str);
$str=str_replace("
$str=str_replace(" ",chr(32),$str);
$str=str_replace(" ",chr(9),$str);
$str=str_replace("&",chr(34),$str);
$str=str_replace("'",chr(39),$str);
$str=str_replace("zuojiankuohaophpcnbr /youjiankuohaophpcn",chr(13),$str);
$str=str_replace("''","'",$str); //开源代码phpfensi.com
return $str;
}
虽然多了一步编码,解码的过程,但是安全方面,会更进一步,要如何做,自己取舍吧.
再附一些代码如下:
function safe_replace($string) {
$string = str_replace(' ','',$string);
$string = str_replace(''','',$string);
$string = str_replace(''','',$string);
$string = str_replace('*','',$string);
$string = str_replace('"','"',$string);
$string = str_replace("'",'',$string);
$string = str_replace('"','',$string);
$string = str_replace(';','',$string);
$string = str_replace('
$string = str_replace('>','>',$string);
$string = str_replace("{",'',$string);
$string = str_replace('}','',$string);
return $string;
}
//更全面的代码如下:
//处理提交的数据
function htmldecode($str) {
if (emptyempty ( $str ) || "" == $str) {
return "";
}
$str = strip_tags ( $str );
$str = htmlspecialchars ( $str );
$str = nl2br ( $str );
$str = str_replace ( "?", "", $str );
$str = str_replace ( "*", "", $str );
$str = str_replace ( "!", "", $str );
$str = str_replace ( "~", "", $str );
$str = str_replace ( "$", "", $str );
$str = str_replace ( "%", "", $str );
$str = str_replace ( "^", "", $str );
$str = str_replace ( "^", "", $str );
$str = str_replace ( "select", "", $str );
$str = str_replace ( "join", "", $str );
$str = str_replace ( "union", "", $str );
$str = str_replace ( "where", "", $str );
$str = str_replace ( "insert", "", $str );
$str = str_replace ( "delete", "", $str );
$str = str_replace ( "update", "", $str );
$str = str_replace ( "like", "", $str );
$str = str_replace ( "drop", "", $str );
$str = str_replace ( "create", "", $str );
$str = str_replace ( "modify", "", $str );
$str = str_replace ( "rename", "", $str );
$str = str_replace ( "alter", "", $str );
$str = str_replace ( "cast", "", $str );
$farr = array ("//s+/", //过滤多余的空白
"/]*?)>/isU", //过滤
;
$tarr = array (" ", "", //如果要直接清除不安全的标签，这里可以留空
"" );
return $str;
}
