本节内容：
str_replace函数防注入、XSS攻击等
说明：
str_replace()函数可以用来替换指定字符，也可以使用该函数过滤敏感字符，以达到防注入的目的。
例子，PHP各种过滤字符函数
复制代码 代码示例:
<?php
/**
* 安全过滤函数
*
* @param $string
* @return string
*/
function safe_replace($string) {
$string = str_replace('%20','',$string);
$string = str_replace('%27','',$string);
$string = str_replace('%2527','',$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);
$string = str_replace('','',$string);
return $string;
}
?>
代码：
复制代码 代码示例:
<?php
/**
* 返回经addslashes处理过的字符串或数组
* @param $string 需要处理的字符串或数组
* @return mixed
*/
function new_addslashes($string) {
if(!is_array($string)) return addslashes($string);
foreach($string as $key => $val) $string[$key] = new_addslashes($val);
return $string;
}
?>
代码：
复制代码 代码示例:
<?php
//对请求的字符串进行安全处理
/*
$safestep
0 为不处理，
1 为禁止不安全HTML内容(
javascript等)，
2 完全禁止HTML内容，并替换部份不安全字符串（如：eval(、union、CONCAT(、--、等）
*/
function StringSafe($str, $safestep=-1){
$safestep = ($safestep > -1) ? $safestep : 1;
if($safestep == 1){
$str = preg_replace("#script:#i", "ｓｃｒｉｐｔ：", $str);
$str = preg_replace("#<[/]{0,1}(link|meta|ifr|fra|scr)[^>]*>#isU", '', $str);
$str = preg_replace("#[ ]{1,}#", ' ', $str);
return $str;
}else if($safestep == 2){
$str = addslashes(htmlspecialchars(stripslashes($str)));
$str = preg_replace("#eval#i", 'ｅｖａｌ', $str);
$str = preg_replace("#union#i", 'ｕｎｉｏｎ', $str);
$str = preg_replace("#concat#i", 'ｃｏｎｃａｔ', $str);
$str = preg_replace("#--#", '－－', $str);
$str = preg_replace("#[ ]{1,}#", ' ', $str);
return $str;
}else{
return $str;
}
}
?>
代码：
复制代码 代码示例:
<?php
/**
+----------------------------------------------------------
* 输出安全的html，用于过滤危险代码
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $text 要处理的字符串
* @param mixed $tags 允许的标签列表，如 table|td|th|td
+----------------------------------------------------------
* @return string by www.jb200.com
+----------------------------------------------------------
*/
static public function safeHtml($text, $tags = null)
{
$text = trim($text);
//完全过滤注释
$text = preg_replace('/<!--?.*-->/','',$text);
//完全过滤动态代码
$text = preg_replace('/<?|?'.'>/','',$text);
//完全过滤js
$text = preg_replace('/<script?.*/script>/','',$text);
$text = str_replace('[','[',$text);
$text = str_replace(']',']',$text);
$text = str_replace('|','|',$text);
//过滤换行符
$text = preg_replace('/ ? /','',$text);
//br
$text = preg_replace('/<br(s/)?'.'>/i','[br]',$text);
$text = preg_replace('/([br]s*){10,}/i','[br]',$text);
//过滤危险的属性，如：过滤on事件lang js
while(preg_match('/(<[^><]+)(lang|on|action|background|codebase|dynsrc|lowsrc)[^><]+/i',$text,$mat)){
$text=str_replace($mat[0],$mat[1],$text);
}
while(preg_match('/(<[^><]+)(window.|javascript:|js:|about:|file:|document.|vbs:|cookie)([^><]*)/i',$text,$mat)){
$text=str_replace($mat[0],$mat[1].$mat[3],$text);
}
if( empty($allowTags) ) { $allowTags = self::$htmlTags['allow']; }
//允许的HTML标签
$text = preg_replace('/<('.$allowTags.')( [^><[]]*)>/i','[12]',$text);
//过滤多余html
if ( empty($banTag) ) { $banTag = self::$htmlTags['ban']; }
$text = preg_replace('/</?('.$banTag.')[^><]*>/i','',$text);
//过滤合法的html标签
while(preg_match('/<([a-z]+)[^><[]]*>[^><]*</1>/i',$text,$mat)){
$text=str_replace($mat[0],str_replace('>',']',str_replace('<','[',$mat[0])),$text);
}
//转换引号
while(preg_match('/([[^[]]*=s*)("|')([^2=[]]+)2([^[]]*])/i',$text,$mat)){
$text=str_replace($mat[0],$mat[1].'|'.$mat[3].'|'.$mat[4],$text);
}
//空属性转换
$text = str_replace('''','||',$text);
$text = str_replace('""','||',$text);
//过滤错误的单个引号
while(preg_match('/[[^[]]*("|')[^[]]*]/i',$text,$mat)){
$text=str_replace($mat[0],str_replace($mat[1],'',$mat[0]),$text);
}
//转换其它所有不合法的 < >
$text = str_replace('<','<',$text);
$text = str_replace('>','>',$text);
$text = str_replace('"','"',$text);
//反转换
$text = str_replace('[','<',$text);
$text = str_replace(']','>',$text);
$text = str_replace('|','"',$text);
//过滤多余空格
$text = str_replace(' ',' ',$text);
return $text;
}
?>
代码：
复制代码 代码示例:
<?php
function RemoveXSS($val) {
// remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed
// this prevents some character re-spacing such as <javascript>
// note that you have to handle splits with , , and later since they *are* allowed in some // inputs
$val = preg_replace('/([x00-x08,x0b-x0c,x0e-x19])/', '', $val);
// straight replacements, the user should never need these since they're normal characters
// this prevents like <IMG SRC=@avascript:alert('XSS')>
$search = 'abcdefghijklmnopqrstuvwxyz';
$search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
$search .= '1234567890!@#$%^&*()';
$search .= '~`";:?+/={}[]-_|'';
for ($i = 0; $i < strlen($search); $i++) {
// ;? matches the ;, which is optional
// 0{0,7} matches any padded zeros, which are optional and go up to 8 chars
// @ @ search for the hex values
$val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val);//with a ;
// @ @ 0{0,7} matches '0' zero to seven times
$val = preg_replace('/(?{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;
}
// now the only remaining whitespace attacks are , , and
$ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', '
iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');
$ra2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmou
sedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');
$ra = array_merge($ra1, $ra2);
$found = true; // keep replacing as long as the previous round replaced something
while ($found == true) {
$val_before = $val;
for ($i = 0; $i < sizeof($ra); $i++) {
$pattern = '/';
for ($j = 0; $j < strlen($ra[$i]); $j++) {
if ($j > 0) {
$pattern .= '(';
$pattern .= '(&#[xX]0{0,8}([9ab]);)';
$pattern .= '|';
$pattern .= '|(?{0,8}([9|10|13]);)';
$pattern .= ')*';
}
$pattern .= $ra[$i][$j];
}
$pattern .= '/i';
$replacement = substr($ra[$i], 0, 2).'<x>'.substr($ra[$i], 2); // add in <> to nerf the tag
$val = preg_replace($pattern, $replacement, $val); // filter out the hex tags
if ($val_before == $val) {
// no replacements were made, so exit the loop
$found = false;
}
}
}
return $val;
}
?>
