Update TP: PHP - 75_buffer

[felix-20]

Testability pattern

75_buffer

Problem statement

There is not really a problem with the current pattern, this is just a suggestion for a new instance.
According to this there is the function ob_get_clean(), that executes executes both ob_get_contents() and ob_end_clean().
That function is not yet captured by this pattern.

Proposed changes

Introduce a new instance with the following code:

$a = $_GET["p1"]; // source
ob_start();
echo $a;
$x = ob_get_clean();
echo $x; // sink

It is very similar to the first instance, but it only uses one function instead of two.

[compaluca]

@felix-20, @enferas : do we need to keep the original instance? Are you considering that the SAST tool may not have some of these functions properly modeled?

[enferas]

The problem here that static tools will not report the correct sink.
because they will just ignore the buffer.

In this code,

$a = $_GET["p1"]; // source
ob_start();
echo $a;
$x = ob_get_clean();
echo $x; // sink

static tools will report echo $a but actually the correct sink is echo $x.

It is a different case than other patterns because in this pattern we have the alert but not accurate.

I am not sure if we want to delete it or mark it as a special pattern.