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Fix #80663: Recursive SplFixedArray::setSize() may cause double-free #7503

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Fix #80663: Recursive SplFixedArray::setSize() may cause double-free #7503

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fff017b
Fix #80663: Recursive SplFixedArray::setSize() may cause double-free
cmb69 Sep 20, 2021
a5a3c72
Remove superfluous check
cmb69 Sep 20, 2021
e5f150f
Move recursion prevention into the size == 0 branch
cmb69 Sep 20, 2021
f29d2d8
Reset size before destroying
cmb69 Sep 21, 2021
b0af852
Fix test case
cmb69 Sep 21, 2021
c851798
Fix actual issue and restore test expectation
cmb69 Sep 21, 2021
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12 changes: 7 additions & 5 deletions ext/spl/spl_fixedarray.c
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Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ static void spl_fixedarray_init(spl_fixedarray *array, zend_long size) /* {{{ */

static void spl_fixedarray_resize(spl_fixedarray *array, zend_long size) /* {{{ */
{
if (size == array->size) {
if (size == array->size || (size == 0 && array->elements == NULL)) {
/* nothing to do */
return;
}
Expand All @@ -107,14 +107,16 @@ static void spl_fixedarray_resize(spl_fixedarray *array, zend_long size) /* {{{
/* clearing the array */
if (size == 0) {
zend_long i;
zval *elements = array->elements;

array->elements = NULL;

for (i = 0; i < array->size; i++) {
zval_ptr_dtor(&(array->elements[i]));
zval_ptr_dtor(&(elements[i]));
}

if (array->elements) {
efree(array->elements);
array->elements = NULL;
if (elements) {
efree(elements);
}
} else if (size > array->size) {
array->elements = safe_erealloc(array->elements, size, sizeof(zval), 0);
Expand Down
20 changes: 20 additions & 0 deletions ext/spl/tests/bug80663.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
--TEST--
Bug #80663 (Recursive SplFixedArray::setSize() may cause double-free)
--FILE--
<?php
class InvalidDestructor {
public function __destruct() {
try {
$GLOBALS['obj']->setSize(0);
} catch (LogicException $ex) {
echo $ex->getMessage();
}
}
}

$obj = new SplFixedArray(1000);
$obj[0] = new InvalidDestructor();
$obj->setSize(0);
?>
--EXPECT--