Changeset 46912

Timestamp:

12/12/2019 06:43:41 PM (7 years ago)

Author:

SergeyBiryukov

Message:

Update wp_kses_bad_protocol() to recognize : on uri attributes,

wp_kses_bad_protocol() makes sure to validate that uri attributes don’t contain invalid/or not allowed protocols. While this works fine in most cases, there’s a risk that by using the colon html5 named entity, one is able to bypass this function.

Brings r46895 to the 4.4 branch.

Props: xknown, nickdaugherty, peterwilsoncc.

Location:

branches/4.4

Files:

• . (modified) (1 prop)
• src/wp-includes/kses.php (modified) (1 diff)
• tests/phpunit/tests/kses.php (modified) (1 diff)

branches/4.4/src/wp-includes/kses.php

@@ -1397 +1397 @@
 function wp_kses_bad_protocol_once($string, $allowed_protocols, $count = 1 ) {
         $string  = preg_replace( '/(&#0*58(?![;0-9])|&#x0*3a(?![;a-f0-9]))/i', '$1;', $string );
-        $string2 = preg_split( '/:|&#0*58;|&#x0*3a;/i', $string, 2 );
+        $string2 = preg_split( '/:|&#0*58;|&#x0*3a;|:/i', $string, 2 );
         if ( isset($string2[1]) && ! preg_match('%/\?%', $string2[0]) ) {
                 $string = trim( $string2[1] );

branches/4.4/tests/phpunit/tests/kses.php

@@ -170 +170 @@
                 }
 
+                $bad_not_normalized = array(
+                        'dummy:alert(1)',
+                        'javascript:alert(1)',
+                        'javascript&CoLon;alert(1)',
+                        'javascript:alert(1);',
+                        'javascript:alert(1);',
+                        'javascript:alert(1);',
+                        'javascript&#0000058alert(1);',
+                        'jav    ascript:alert(1);',
+                        'javascript:javascript:alert(1);',
+                        'javascript:javascript:alert(1);',
+                        'javascript&#0000058javascript:alert(1);',
+                        'javascript:javascript&#0000058alert(1);',
+                        'javascript&#58alert(1)',
+                );
+                foreach ( $bad_not_normalized as $k => $x ) {
+                        $result = wp_kses_bad_protocol( $x, wp_allowed_protocols() );
+                        if ( ! empty( $result ) && 'alert(1);' !== $result && 'alert(1)' !== $result ) {
+                                $this->fail( "wp_kses_bad_protocol failed on $k, $x. Result: $result" );
+                        }
+                }
+
                 $safe = array(
                         'dummy:alert(1)',