[BUGFIX] Use callback in preg_replace in RemoveXSS 55/24755/2
authorJigal van Hemert <jigal.van.hemert@typo3.org>
Mon, 14 Oct 2013 08:34:52 +0000 (10:34 +0200)
committerMarkus Klein <klein.t3@mfc-linz.at>
Mon, 14 Oct 2013 22:04:14 +0000 (00:04 +0200)
Since PHP 5.5.0 the use of the /e modifier is deprecated in preg_replace.
Use callback function instead.
Also change comments to CGL format.

Change-Id: I44f12e8bfa1c976e494dae847cc6c53d15ed7c2d
Fixes: #52771
Releases: 6.0, 6.1, 6.2
Reviewed-on: https://review.typo3.org/24755
Reviewed-by: Markus Klein
Tested-by: Markus Klein
typo3/contrib/RemoveXSS/RemoveXSS.php

index eb07bc4..b492f6e 100644 (file)
@@ -32,25 +32,37 @@ class RemoveXSS {
         * @return string Input string with potential XSS code removed
         */
        public static function process($val, $replaceString = '<x>') {
-                       // don't use empty $replaceString because then no XSS-remove will be done
+               // Don't use empty $replaceString because then no XSS-remove will be done
                if ($replaceString == '') {
                        $replaceString = '<x>';
                }
-                       // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed
-                       // this prevents some character re-spacing such as <java\0script>
-                       // note that you have to handle splits with \n, \r, and \t later since they *are* allowed in some inputs
+               // Remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed.
+               // This prevents some character re-spacing such as <java\0script>
+               // Note that you have to handle splits with \n, \r, and \t 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=&#X40&#X61&#X76&#X61&#X73&#X63&#X72&#X69&#X70&#X74&#X3A&#X61&#X6C&#X65&#X72&#X74&#X28&#X27&#X58&#X53&#X53&#X27&#X29>
-               $searchHexEncodings = '/&#[xX]0{0,8}(21|22|23|24|25|26|27|28|29|2a|2b|2d|2f|30|31|32|33|34|35|36|37|38|39|3a|3b|3d|3f|40|41|42|43|44|45|46|47|48|49|4a|4b|4c|4d|4e|4f|50|51|52|53|54|55|56|57|58|59|5a|5b|5c|5d|5e|5f|60|61|62|63|64|65|66|67|68|69|6a|6b|6c|6d|6e|6f|70|71|72|73|74|75|76|77|78|79|7a|7b|7c|7d|7e);?/ie';
-               $searchUnicodeEncodings = '/&#0{0,8}(33|34|35|36|37|38|39|40|41|42|43|45|47|48|49|50|51|52|53|54|55|56|57|58|59|61|63|64|65|66|67|68|69|70|71|72|73|74|75|76|77|78|79|80|81|82|83|84|85|86|87|88|89|90|91|92|93|94|95|96|97|98|99|100|101|102|103|104|105|106|107|108|109|110|111|112|113|114|115|116|117|118|119|120|121|122|123|124|125|126);?/ie';
+               // Straight replacements, the user should never need these since they're normal characters.
+               // This prevents like <IMG SRC=&#X40&#X61&#X76&#X61&#X73&#X63&#X72&#X69&#X70&#X74&#X3A&#X61&#X6C&#X65&#X72&#X74&#X28&#X27&#X58&#X53&#X53&#X27&#X29>
+               $searchHexEncodings = '/&#[xX]0{0,8}(21|22|23|24|25|26|27|28|29|2a|2b|2d|2f|30|31|32|33|34|35|36|37|38|39|3a|3b|3d|3f|40|41|42|43|44|45|46|47|48|49|4a|4b|4c|4d|4e|4f|50|51|52|53|54|55|56|57|58|59|5a|5b|5c|5d|5e|5f|60|61|62|63|64|65|66|67|68|69|6a|6b|6c|6d|6e|6f|70|71|72|73|74|75|76|77|78|79|7a|7b|7c|7d|7e);?/i';
+               $searchUnicodeEncodings = '/&#0{0,8}(33|34|35|36|37|38|39|40|41|42|43|45|47|48|49|50|51|52|53|54|55|56|57|58|59|61|63|64|65|66|67|68|69|70|71|72|73|74|75|76|77|78|79|80|81|82|83|84|85|86|87|88|89|90|91|92|93|94|95|96|97|98|99|100|101|102|103|104|105|106|107|108|109|110|111|112|113|114|115|116|117|118|119|120|121|122|123|124|125|126);?/i';
                while (preg_match($searchHexEncodings, $val) || preg_match($searchUnicodeEncodings, $val)) {
-                       $val = preg_replace($searchHexEncodings, "chr(hexdec('\\1'))", $val);
-                       $val = preg_replace($searchUnicodeEncodings, "chr('\\1')", $val);
+                       $val = preg_replace_callback(
+                               $searchHexEncodings,
+                               function ($matches) {
+                                       return chr(hexdec($matches[1]));
+                               },
+                               $val
+                       );
+                       $val = preg_replace_callback(
+                               $searchUnicodeEncodings,
+                               function ($matches) {
+                                       return chr($matches[1]);
+                               },
+                               $val
+                       );
                }
 
-                       // now the only remaining whitespace attacks are \t, \n, and \r
+               // Now the only remaining whitespace attacks are \t, \n, and \r
                $ra1 = array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed',
                        'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base', 'video', 'audio', 'track',
                        'canvas', 'onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut',
@@ -86,13 +98,13 @@ class RemoveXSS {
                        'onsuspend', 'ontimeupdate', 'onundo', 'onunload', 'onvolumechange', 'onwaiting');
                $ra_protocol = array('javascript', 'vbscript', 'expression');
 
-                       //remove the potential &#xxx; stuff for testing
+               // Remove the potential &#xxx; stuff for testing
                $val2 = preg_replace('/(&#[xX]?0{0,8}(9|10|13|a|b);?)*\s*/i', '', $val);
                $ra = array();
 
                foreach ($ra1 as $ra1word) {
-                               // stripos is faster than the regular expressions used later and because the words we're looking for only have
-                               // chars < 0x80 we can use the non-multibyte safe version
+                       // Stripos is faster than the regular expressions used later and because the words we're looking for only have
+                       // chars < 0x80 we can use the non-multibyte safe version.
                        if (stripos($val2, $ra1word ) !== FALSE ) {
                                        //keep list of potential words that were found
                                if (in_array($ra1word, $ra_protocol, TRUE)) {
@@ -104,13 +116,13 @@ class RemoveXSS {
                                if (in_array($ra1word, $ra_attribute, TRUE)) {
                                        $ra[] = array($ra1word, 'ra_attribute');
                                }
-                                       //some keywords appear in more than one array
-                                       //these get multiple entries in $ra, each with the appropriate type
+                               // Some keywords appear in more than one array.
+                               // These get multiple entries in $ra, each with the appropriate type
                        }
                }
-                       //only process potential words
+               // Only process potential words
                if (count($ra) > 0) {
-                               // keep replacing as long as the previous round replaced something
+                       // Keep replacing as long as the previous round replaced something
                        $found = TRUE;
                        while ($found == TRUE) {
                                $val_before = $val;
@@ -122,29 +134,29 @@ class RemoveXSS {
                                                }
                                                $pattern .= $ra[$i][0][$j];
                                        }
-                                               //handle each type a little different (extra conditions to prevent false positives a bit better)
+                                       // Handle each type a little different (extra conditions to prevent false positives a bit better)
                                        switch ($ra[$i][1]) {
                                                case 'ra_protocol':
-                                                               //these take the form of e.g. 'javascript:'
+                                                       // These take the form of e.g. 'javascript:'
                                                        $pattern .= '((&#[xX]0{0,8}([9ab]);?)|(&#0{0,8}(9|10|13);?)|\s)*(?=:)';
                                                        break;
                                                case 'ra_tag':
-                                                               //these take the form of e.g. '<SCRIPT[^\da-z] ....';
+                                                       // These take the form of e.g. '<SCRIPT[^\da-z] ....';
                                                        $pattern = '(?<=<)' . $pattern . '((&#[xX]0{0,8}([9ab]);?)|(&#0{0,8}(9|10|13);?)|\s)*(?=[^\da-z])';
                                                        break;
                                                case 'ra_attribute':
-                                                               //these take the form of e.g. 'onload='  Beware that a lot of characters are allowed
-                                                               //between the attribute and the equal sign!
+                                                       // These take the form of e.g. 'onload='  Beware that a lot of characters are allowed
+                                                       // between the attribute and the equal sign!
                                                        $pattern .= '[\s\!\#\$\%\&\(\)\*\~\+\-\_\.\,\:\;\?\@\[\/\|\\\\\]\^\`]*(?==)';
                                                        break;
                                        }
                                        $pattern = '/' . $pattern . '/i';
-                                               // add in <x> to nerf the tag
+                                       // Add in <x> to nerf the tag
                                        $replacement = substr_replace($ra[$i][0], $replaceString, 2, 0);
-                                               // filter out the hex tags
+                                       // Filter out the hex tags
                                        $val = preg_replace($pattern, $replacement, $val);
                                        if ($val_before == $val) {
-                                                       // no replacements were made, so exit the loop
+                                               // No replacements were made, so exit the loop
                                                $found = FALSE;
                                        }
                                }
@@ -154,4 +166,4 @@ class RemoveXSS {
        }
 }
 
-?>
\ No newline at end of file
+?>