integer overflow in session.c:1353

[chongwick]

Description

The following code:

<?php
session_set_cookie_params(PHP_INT_MAX, '/', null, false, true);
session_start();
?>

Resulted in this output:

/home/dan/php-8.3.9/ext/session/session.c:1353:5: runtime error: signed integer overflow: 1728342208 + 9223372036854775807 cannot be represented in type 'long int'

Also, not tested with 8.3.12, yet.

PHP Version

8.3.9

Operating System

No response

[MarcusXavierr]

I've tested it on a docker container with PHP 8.3.9 and went fine

I've also tested on my machine with PHP 8.2.15 and also didn't had any problem

Did you make any steps besides running this code?

[MarcusXavierr]

Maybe the error occurs because the PS(cookie_lifetime) is already the max positive size of long.

But why does this overflow doesn't break anything on my machine?

And if the overflow is the problem, and the user can set cookie_lifetime to the max long int value, what are our options? Turning t into unsigned long?
Test the possible overflow before assigning t, and treating the overflow case with the LONG_MAX value from limits.h?

[cmb69]

But why does this overflow doesn't break anything on my machine?

That overflow is undefined behavior; it may not necessarily cause issues, but should be fixed nonetheless. To reliably detect it, you either need to debug manually, or to employ something like UBSan.