Fix use-after-free during lazy object initialization#119
Closed
iliaal wants to merge 1 commit into
Closed
Conversation
zend_lazy_object_revert_init() and zend_lazy_object_init_proxy() dropped a property value's refcount while the slot or dynamic-properties table still aliased it, so a value whose destructor reaches back through a reference cycle (unset($this->obj->prop)) freed it twice. Clear the slot and detach the properties table before dropping the refcount. Fixes phpGH-22399
7e34907 to
d924213
Compare
Owner
Author
|
Superseded by the upstream PR php#22401. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Lazy object initialization destroyed property values while the slot or the dynamic-properties
HashTablestill aliased them, so a value whose__destructreaches back through a reference cycle (unset($this->obj->prop)) double-freed it, a UAF inzend_objects_store_del. The fix clears the slot and detaches the properties table before dropping the refcount, across all four destruction sites inzend_lazy_object_revert_initandzend_lazy_object_init_proxy(declared and dynamic properties, ghost revert and proxy cleanup); verified under ASAN.Fixes php#22399