line check iteration on non-String options value

[stklcode]

Originally reported in the WP support forums: https://wordpress.org/support/topic/php-notice-breaks-scan/

antivirus/inc/class-antivirus-checkinternals.php

Lines 235 to 238 in fbc3614

	// Check option.
	if ( $matches && $matches[1] && self::_check_file_line( get_option( $matches[1] ), $num ) ) {
	array_push( $results, 'get_option' );
	}

We do scan for a get_option() call, get the option and execute the line check again on the value. The return value however can have any type, not only string. Implicit conversion works quite well for most primitives, but fails for objects and arrays.

I am unsure about the intention behind this routine.
So do we need to add some sanitization here? Allow only scalar types that convert to string? Stringify the value? Personally I would simply drop the options check.

[stklcode]

I tried to resolve the problem introducing a is_scalar (is_string should also do the job, because we do not check for numbers or "true"/"false") filter:

// Check option.
if ( $matches && $matches[1]) {
	$opt_value = get_option( $matches[1] );
	if ( is_scalar( $opt_value ) && self::_check_file_line(strval( $opt_value ), $num ) ) {
		array_push( $results, 'get_option' );
	}
}

Stumbled across one really bad case. Imagine the following line of code:

$o = get_option( 'endless recursion' );

with the option value (string): get_option( 'endless recursion' )

This call does not cause any damage in the theme without an additional eval() or similar, but it breaks Antivirus causing in infinite loop on the server!