Bug #78409 [Ana->Csd]: Segfault when creating instance of ArrayIterator without constructor
Edit report at https://bugs.php.net/bug.php?id=78409&edit=1
ID: 78409
Updated by: nikic@php.net
Reported by: nicolas dot grekas+php at gmail dot com
Summary: Segfault when creating instance of ArrayIterator
without constructor
-Status: Analyzed
+Status: Closed
Type: Bug
Package: Reproducible crash
PHP Version: 7.4.0beta2
Block user comment: N
Private report: N
New Comment:
Automatic comment on behalf of nikita.ppv@gmail.com
Revision: http://git.php.net/?p=php-src.git;a=commit;h=34885408db9e16c48e8c25195c39e0ef758faaaa
Log: Fixed bug #78409
Previous Comments:
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[2019-08-15 08:35:26] nikic@php.net
I believe the root cause here is this:
$a = new ArrayObject;
$u = [
0,
[],
[],
];
$a->__unserialize($u);
var_dump($u);
array(3) {
[0]=>
int(0)
[1]=>
NULL <-- changed to NULL
[2]=>
array(0) {
}
}
------------------------------------------------------------------------
[2019-08-13 17:00:38] nicolas dot grekas+php at gmail dot com
Description:
------------
This is related to the new serialization mechanism of PHP 7.4.
I don't have a better reproducer because when I try to isolate the crash, it works...
Here is my reproducer, sorry I don't have a better one for now:
Clone https://github.com/nicolas-grekas/symfony
checkout branch "ve-php74"
Then run
./phpunit src/Symfony/Component/VarExporter/ --do-not-cache-result --filter testExport#6
boom
What the code does is that it:
- uses newInstanceWithoutConstructor to create an ArrayIterator
- clones that instance
- calls __unserialize on the clone instance with a valid payload
The crash happens after these step, when e.g. calling print_r() on the object.
When done "manually", it works. But in the context of the test case, it segfaults.
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Edit this bug report at https://bugs.php.net/bug.php?id=78409&edit=1
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