Fix OSS Fuzz #61865: Undef variable in ++/-- for declared property that is unset in error handler #12114
Conversation
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
iluuu1994
reviewed
Sep 3, 2023
Zend/zend_object_handlers.c
Outdated
| zend_error(E_WARNING, "Undefined property: %s::$%s", ZSTR_VAL(zobj->ce->name), ZSTR_VAL(name)); | ||
| /* We set the retval to null AFTER the warning so that an error handler cannot mess | ||
| * with the property value... */ | ||
| ZVAL_NULL(retval); |
Member
There was a problem hiding this comment.
This can leak.
class Foo {}
class C {
public $a;
function errorHandler($errno, $errstr) {
$this->a = new Foo();
}
}
$c = new C;
set_error_handler([$c,'errorHandler']);
unset($c->a);
(++$c->a);
var_dump($c->a);Just wrapping the ZVAL_NULL in a if (Z_TYPE_P(retval) == IS_UNDEF) { should do. This will change the behavior to throw a "TypeError: Cannot increment Foo" exception, which I think is what I would expect.
Member
There was a problem hiding this comment.
I guess if we want that, then for consistency the zend_hash_update for the dynamic case should become zend_hash_add instead too?
Member
There was a problem hiding this comment.
@nielsdos That probably makes sense. The leak doesn't happen in that case because the hash table takes care of releasing the old value.
Member
Girgias
force-pushed
the
oss-61865-in-dec-declared-prop-undef
branch
from
962e84f to
28df23b
Compare
ndossche
added a commit
to ndossche/php-src
that referenced
this pull request
Sep 3, 2023
With the fix in php#12114, the behaviour would change for non-dynamic properties. Align the behaviour for dynamic properties to be the same.
…at is unset in error handler Reorder when we assign the property value to NULL which is identical to a3a3964 Just for the declared property case instead of dynamic.
Girgias
force-pushed
the
oss-61865-in-dec-declared-prop-undef
branch
from
28df23b to
9c123ac
Compare
iluuu1994
approved these changes
Sep 5, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
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.
Reorder when we assign the property value to NULL which is identical to a3a3964
Just for the declared property case instead of dynamic.