FFICasterTest::testCastNonTrailingCharPointer() breaks PHPs community build #47668
Description
Symfony version(s) affected
6.2
Description
symfony/src/Symfony/Component/VarDumper/Tests/Caster/FFICasterTest.php
Lines 194 to 205 in e6d6bed
See https://github.com/iluuu1994/php-src/actions/runs/3106907448/jobs/5034370701.
How to reproduce
Possible Solution
The NUL byte should be part of the array, otherwise this is writing to unrelated memory. The memory sanitizer complains about $pointer[$actualLength] = "\x01";, because the assignment happens to unowned memory. The string should be allocated as $string = \FFI::new('char['.($actualLength + 1).']'); to allow this, although that likely defeats the purpose of the test as there is probably another NUL byte right after. Printing char* is likely unsafe because user allocated C strings are not guaranteed to be NUL-terminated. Just reading from the unowned memory is also unsafe and can cause SEGFAULTs.
Additional Context
No response