str_replace()函数的使用就是用来替换指定字符了,那么我们正好可以利用它这一点来过滤敏感字符以太到防注入的效果,下面我来给大家总结了一些方法,给大家分享一下.

PHP各种过滤字符函数,代码如下:

1. <?php
2. /**
3. * 安全过滤函数
4. *
5. * @param $string
6. * @return string
7. */
8. function safe_replace($string) {
9. $string = str_replace('%20','',$string);
10. $string = str_replace('%27','',$string);
11. $string = str_replace('%2527','',$string);
12. $string = str_replace('*','',$string);
13. $string = str_replace('"','&quot;',$string);
14. $string = str_replace("'",'',$string);
15. $string = str_replace('"','',$string);
16. $string = str_replace(';','',$string);
17. $string = str_replace('<','&lt;',$string);
18. $string = str_replace('>','&gt;',$string);
19. $string = str_replace("{",'',$string);
20. $string = str_replace('}','',$string);
21. $string = str_replace('','',$string);
22. return $string;
23. }
24. ?>
25. <?php
26. /**
27. * 返回经addslashes处理过的字符串或数组
28. * @param $string 需要处理的字符串或数组
29. * @return mixed
30. */
31. function new_addslashes($string) {
32. if(!is_array($string)) return addslashes($string);
33. foreach($string as $key => $val) $string[$key] = new_addslashes($val);
34. return $string;
35. }
36. ?>
37. <?php
38. //对请求的字符串进行安全处理
39. /*
40. $safestep
41. 0 为不处理，
42. 1 为禁止不安全HTML内容(javascript等)，
43. 2 完全禁止HTML内容，并替换部份不安全字符串（如：eval(、union、CONCAT(、--、等）
44. */
45. function StringSafe($str, $safestep=-1){
46. $safestep = ($safestep > -1) ? $safestep : 1;
47. if($safestep == 1){
48. $str = preg_replace("#script:#i", "ｓｃｒｉｐｔ：", $str);
49. $str = preg_replace("#<[/]{0,1}(link|meta|ifr|fra|scr)[^>]*>#isU", '', $str);
50. $str = preg_replace("#[ ]{1,}#", ' ', $str);
51. return $str;
52. }else if($safestep == 2){
53. $str = addslashes(htmlspecialchars(stripslashes($str)));
54. $str = preg_replace("#eval#i", 'ｅｖａｌ', $str);
55. $str = preg_replace("#union#i", 'ｕｎｉｏｎ', $str);
56. $str = preg_replace("#concat#i", 'ｃｏｎｃａｔ', $str);
57. $str = preg_replace("#--#", '－－', $str);
58. $str = preg_replace("#[ ]{1,}#", ' ', $str);
59. return $str;
60. }else{
61. return $str;
62. }
63. }
64. ?>
65. <?php
66. /**
67. +----------------------------------------------------------
68. * 输出安全的html，用于过滤危险代码
69. +----------------------------------------------------------
70. * @access public
71. +----------------------------------------------------------
72. * @param string $text 要处理的字符串
73. * @param mixed $tags 允许的标签列表，如 table|td|th|td
74. +----------------------------------------------------------
75. * @return string
76. +----------------------------------------------------------
77. */
78. static public function safeHtml($text, $tags = null)
79. {
80. $text = trim($text);
81. //完全过滤注释
82. $text = preg_replace('/<!--?.*-->/','',$text);
83. //完全过滤动态代码
84. $text = preg_replace('/<?|?'.'>/','',$text);
85. //完全过滤js
86. $text = preg_replace('/<script?.*/script>/','',$text);
87. $text = str_replace('[','&#091;',$text);
88. $text = str_replace(']','&#093;',$text);
89. $text = str_replace('|','&#124;',$text);
90. //过滤换行符
91. $text = preg_replace('/ ? /','',$text);
92. //br
93. $text = preg_replace('/<br(s/)?'.'>/i','[br]',$text);
94. $text = preg_replace('/([br]s*){10,}/i','[br]',$text);
95. //过滤危险的属性，如：过滤on事件lang js
96. while(preg_match('/(<[^><]+)(lang|on|action|background|codebase|dynsrc|lowsrc)[^><]+/i',$text,$mat)){
97. $text=str_replace($mat[0],$mat[1],$text);
98. }
99. while(preg_match('/(<[^><]+)(window.|javascript：|js:|about:|file:|document.|vbs:|cookie)([^><]*)/i',$text,$mat)){
100. $text=str_replace($mat[0],$mat[1].$mat[3],$text);
101. }
102. if( emptyempty($allowTags) ) { $allowTags = self::$htmlTags['allow']; }
103. //允许的HTML标签
104. $text = preg_replace('/<('.$allowTags.')( [^><[]]*)>/i','[12]',$text);
105. //过滤多余html
106. if ( emptyempty($banTag) ) { $banTag = self::$htmlTags['ban']; }
107. $text = preg_replace('/</?('.$banTag.')[^><]*>/i','',$text);
108. //过滤合法的html标签
109. while(preg_match('/<([a-z]+)[^><[]]*>[^><]*</1>/i',$text,$mat)){
110. $text=str_replace($mat[0],str_replace('>',']',str_replace('<','[',$mat[0])),$text);
111. }
112. //转换引号
113. while(preg_match('/([[^[]]*=s*)("|')([^2=[]]+)2([^[]]*])/i',$text,$mat)){
114. $text=str_replace($mat[0],$mat[1].'|'.$mat[3].'|'.$mat[4],$text);
115. }
116. //空属性转换
117. $text = str_replace('''','||',$text);
118. $text = str_replace('""','||',$text);
119. //过滤错误的单个引号
120. while(preg_match('/[[^[]]*("|')[^[]]*]/i',$text,$mat)){
121. $text=str_replace($mat[0],str_replace($mat[1],'',$mat[0]),$text);
122. }
123. //转换其它所有不合法的 < >
124. $text = str_replace('<','&lt;',$text);
125. $text = str_replace('>','&gt;',$text);
126. $text = str_replace('"','&quot;',$text);
127. //反转换
128. $text = str_replace('[','<',$text);
129. $text = str_replace(']','>',$text);
130. $text = str_replace('|','"',$text);
131. //过滤多余空格
132. $text = str_replace(' ',' ',$text);
133. return $text;
134. }
135. ?>
136. <?php
137. function RemoveXSS($val) {
138. // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed
139. // this prevents some character re-spacing such as <javascript>
140. // note that you have to handle splits with , , and later since they *are* allowed in some // inputs
141. $val = preg_replace('/([x00-x08,x0b-x0c,x0e-x19])/', '', $val);
142. // straight replacements, the user should never need these since they're normal characters
143. // this prevents like <IMG SRC=@avascript:alert('XSS')>
144. $search = 'abcdefghijklmnopqrstuvwxyz';
145. $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
146. $search .= '1234567890!@#$%^&*()';
147. $search .= '~`";:?+/={}[]-_|'';
148. for ($i = 0; $i < strlen($search); $i++) {
149. // ;? matches the ;, which is optional
150. // 0{0,7} matches any padded zeros, which are optional and go up to 8 chars
151. // @ @ search for the hex values
152. $val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val);//with a ;
153. // @ @ 0{0,7} matches '0' zero to seven times
154. $val = preg_replace('/(&#0{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;
155. }
156. // now the only remaining whitespace attacks are , , and
157. $ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');
158. $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', 'onmousedown', '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');
159. $ra = array_merge($ra1, $ra2);
160. $found = true; // keep replacing as long as the previous round replaced something
161. while ($found == true) {
162. $val_before = $val;
163. for ($i = 0; $i < sizeof($ra); $i++) {
164. $pattern = '/';
165. for ($j = 0; $j < strlen($ra[$i]); $j++) {
166. if ($j > 0) {
167. $pattern .= '(';
168. $pattern .= '(&#[xX]0{0,8}([9ab]);)';
169. $pattern .= '|';
170. $pattern .= '|(&#0{0,8}([9|10|13]);)';
171. $pattern .= ')*';
172. }
173. $pattern .= $ra[$i][$j];
174. }
175. $pattern .= '/i';
176. $replacement = substr($ra[$i], 0, 2).'<x>'.substr($ra[$i], 2); // add in <> to nerf the tag
177. $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags
178. if ($val_before == $val) {
179. // no replacements were made, so exit the loop
180. $found = false;
181. }
182. } //开源代码phpfensi.com
183. }
184. return $val;
185. }
186. ?>