>function invalideregtest($input)
>
>script just check $topic by invalideregtest function

I think this function just *tries* to check inputs, but doesn't
succeed. Did you do any live testing using $topic ?

We should expect to see more erroneous cleansing/checking functions as
programmers attempt to implement security in their products.

> $checkcount = 0;

This matters later on.

> //$exinput = str_split($input);
> $countname = count($exinput);

Since the assignment of $exinput is commented out, the variable is
undefined. So, $countname is set to 0.

(This was probably commented out because the function doesn't exist in
PHP 4.)

> for($i=0; $i<$countname; $i++)
> {

Since $countname is 0, this loop is not entered.

> if($checkcount != 0)
> {
> $input = "no";
> }
> else
> {
> $input = "yes";
> }

Since $checkcount is 0, the function always returns "yes", meaning
"the input looks valid to me."

<SCRIPT>abc</SCRIPT> === yes

ABCDE GHIF AKLSM === yes

ABCDEGHIFAKLSM === yes

There might be other logic errors in the function, but this is the
most obvious one.

- Steve

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