Make WordPress Core

Changeset 46908


Ignore:
Timestamp:
12/12/2019 06:37:13 PM (4 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 4.0 branch.

Props: xknown, nickdaugherty, peterwilsoncc.

Location:
branches/4.0
Files:
3 edited

Legend:

Unmodified
Added
Removed
  • branches/4.0

  • branches/4.0/src/wp-includes/kses.php

    r46015 r46908  
    13421342function wp_kses_bad_protocol_once($string, $allowed_protocols, $count = 1 ) {
    13431343    $string  = preg_replace( '/(&#0*58(?![;0-9])|&#x0*3a(?![;a-f0-9]))/i', '$1;', $string );
    1344     $string2 = preg_split( '/:|&#0*58;|&#x0*3a;/i', $string, 2 );
     1344    $string2 = preg_split( '/:|&#0*58;|&#x0*3a;|:/i', $string, 2 );
    13451345    if ( isset($string2[1]) && ! preg_match('%/\?%', $string2[0]) ) {
    13461346        $string = trim( $string2[1] );
  • branches/4.0/tests/phpunit/tests/kses.php

    r46015 r46908  
    170170        }
    171171
     172        $bad_not_normalized = array(
     173            'dummy:alert(1)',
     174            'javascript:alert(1)',
     175            'javascript&CoLon;alert(1)',
     176            'javascript:alert(1);',
     177            'javascript:alert(1);',
     178            'javascript:alert(1);',
     179            'javascript&#0000058alert(1);',
     180            'jav    ascript:alert(1);',
     181            'javascript:javascript:alert(1);',
     182            'javascript:javascript:alert(1);',
     183            'javascript&#0000058javascript:alert(1);',
     184            'javascript:javascript&#0000058alert(1);',
     185            'javascript&#58alert(1)',
     186        );
     187        foreach ( $bad_not_normalized as $k => $x ) {
     188            $result = wp_kses_bad_protocol( $x, wp_allowed_protocols() );
     189            if ( ! empty( $result ) && 'alert(1);' !== $result && 'alert(1)' !== $result ) {
     190                $this->fail( "wp_kses_bad_protocol failed on $k, $x. Result: $result" );
     191            }
     192        }
     193
    172194        $safe = array(
    173195            'dummy:alert(1)',
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