Inside `zend_object_std_dtor` the weakrefs are notified after the destruction
of properties already took place. In this test case, the destructor of an anon
class will be invoked due to the property destruction. That class has a
weak reference to its parent. This means that the destructor can access
parent properties that already have been destroyed, resulting in a UAF.
Fix this by notifying the weakrefs at the start of the object's
destruction.
Closes GH-13613.
This undoes the change from a4b209fdcf
and addresses the original problem by dropping the unrefs during
shutdown. All objects should get unref'ed without that, and this
code path should only get hit for dangling references due to
bailout.
Alternatively we'd have to relax some assertions that check that the
object is part of the weakrefs table, which seems worse.
Fixes oss-fuzz #40090.
While performing resource -> object migrations, we're adding
defensive classes that are final, non-serializable and non-clonable
(unless they are, of course). This path adds a ZEND_ACC_NO_DYNAMIC_PROPERTIES
flag, that also forbids the creation of dynamic properties on these objects.
This is a subset of #3931 and targeted at internal usage only
(though may be extended to userland at some point in the future).
It's already possible to achieve this (what the removed
WeakRef/WeakMap code does), but there's some caveats: First, this
simple approach is only possible if the class has no declared
properties, otherwise it's necessary to special-case those
properties. Second, it's easy to make it overly strict, e.g. by
forbidding isset($obj->prop) as well. And finally, it requires a
lot of boilerplate code for each class.
Closes GH-5572.
