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Fix missing write lock validation in SplHeap::next() #21448

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Fix missing write lock validation in SplHeap::next() #21448

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e17cfab
Fix missing write lock validation in SplHeap::next()
ndossche Mar 14, 2026
e0dff23
fix incorrect flag
ndossche Mar 15, 2026
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6 changes: 5 additions & 1 deletion ext/spl/spl_heap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -961,7 +961,7 @@ static void spl_heap_it_move_forward(zend_object_iterator *iter) /* {{{ */
{
spl_heap_object *object = Z_SPLHEAP_P(&iter->data);

if (UNEXPECTED(spl_heap_consistency_validations(object, false) != SUCCESS)) {
if (UNEXPECTED(spl_heap_consistency_validations(object, true) != SUCCESS)) {
return;
}

Expand Down Expand Up @@ -992,6 +992,10 @@ PHP_METHOD(SplHeap, next)
RETURN_THROWS();
}

if (UNEXPECTED(spl_heap_consistency_validations(intern, true) != SUCCESS)) {
RETURN_THROWS();
}

spl_ptr_heap_delete_top(intern->heap, NULL, ZEND_THIS);
}
/* }}} */
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34 changes: 34 additions & 0 deletions ext/spl/tests/heap_next_write_lock.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
--TEST--
SplHeap::next() write lock
--CREDITS--
cnitlrt
--FILE--
<?php

class EvilPQ extends SplPriorityQueue {
private bool $did = false;

public function compare(mixed $p1, mixed $p2): int {
if (!$this->did) {
$this->did = true;
// Re-entrant write during internal heap insertion comparison.
if (!$this->isEmpty()) {
$this->next(); // no write-lock validation
}
}
return parent::compare($p1, $p2);
}
}

$q = new EvilPQ();
try {
for ($i = 0; $i < 200; $i++) {
$q->insert("d$i", 100 - $i);
}
} catch (RuntimeException $e) {
echo $e::class, ": ", $e->getMessage(), "\n";
}

?>
--EXPECT--
RuntimeException: Heap cannot be changed when it is already being modified.
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