@param string $checkname What $checkvalue is checking for. * @param mixed $checkvalue What constraint the value should pass. * @return bool Whether check passes. */ function wp_kses_check_attr_val( $value, $vless, $checkname, $checkvalue ) { $ok = true; switch ( strtolower( $checkname ) ) { case 'maxlen': /* * The maxlen check makes sure that the attribute value has a length not * greater than the given value. This can be used to avoid Buffer Overflows * in WWW clients and various Internet servers. */ if ( strlen( $value ) > $checkvalue ) { $ok = false; } break; case 'minlen': /* * The minlen check makes sure that the attribute value has a length not * smaller than the given value. */ if ( strlen( $value ) < $checkvalue ) { $ok = false; } break; case 'maxval': /* * The maxval check does two things: it checks that the attribute value is * an integer from 0 and up, without an excessive amount of zeroes or * whitespace (to avoid Buffer Overflows). It also checks that the attribute * value is not greater than the given value. * This check can be used to avoid Denial of Service attacks. */ if ( ! preg_match( '/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value ) ) { $ok = false; } if ( $value > $checkvalue ) { $ok = false; } break; case 'minval': /* * The minval check makes sure that the attribute value is a positive integer, * and that it is not smaller than the given value. */ if ( ! preg_match( '/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value ) ) { $ok = false; } if ( $value < $checkvalue ) { $ok = false; } break; case 'valueless': /* * The valueless check makes sure if the attribute has a value * (like ``) or not (`