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Fix GH-24989: Use-after-free in GC when an exception is thrown. #24993

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Fix GH-24989: Use-after-free in GC when an exception is thrown. #24993

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29 changes: 29 additions & 0 deletions Zend/tests/gh24989.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
--TEST--
GH-24989 (Use-after-free in GC when an exception is thrown)
--CREDITS--
vi3tL0u1s
--FILE--
<?php
class D { function __destruct() { gc_collect_cycles(); } }

function loop_var() {
foreach (range(1, 2) as $v) {
$x = [new D, throw new Exception('loop')];
}
}

function tmp_var() {
$x = [range(1, 2), [new D, throw new Exception('tmp')]];
}

foreach (['loop_var', 'tmp_var'] as $f) {
try {
$f();
} catch (Exception $e) {
echo $e::class, ': ', $e->getMessage(), PHP_EOL;
}
}
?>
--EXPECT--
Exception: loop
Exception: tmp
16 changes: 16 additions & 0 deletions Zend/tests/gh24989_uncaught.phpt
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@@ -0,0 +1,16 @@
--TEST--
GH-24989 (Use-after-free in GC when an exception is thrown, uncaught)
--CREDITS--
vi3tL0u1s
--FILE--
<?php
class D { function __destruct() { gc_collect_cycles(); } }
foreach (range(1, 2) as $v) {
$x = [new D, throw new Exception];
}
?>
--EXPECTF--
Fatal error: Uncaught Exception in %s:%d
Stack trace:
#0 {main}
thrown in %s on line %d
10 changes: 8 additions & 2 deletions Zend/zend_execute.c
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Expand Up @@ -4713,7 +4713,10 @@ static void cleanup_live_vars(zend_execute_data *execute_data, uint32_t op_num,
}

if (kind == ZEND_LIVE_TMPVAR) {
zval_ptr_dtor_nogc(var);
zval tmp;
ZVAL_COPY_VALUE(&tmp, var);
ZVAL_UNDEF(var);
zval_ptr_dtor_nogc(&tmp);
} else if (kind == ZEND_LIVE_NEW) {
zend_object *obj;
ZEND_ASSERT(Z_TYPE_P(var) == IS_OBJECT);
Expand All @@ -4724,7 +4727,10 @@ static void cleanup_live_vars(zend_execute_data *execute_data, uint32_t op_num,
if (Z_TYPE_P(var) != IS_ARRAY && Z_FE_ITER_P(var) != (uint32_t)-1) {
zend_hash_iterator_del(Z_FE_ITER_P(var));
}
zval_ptr_dtor_nogc(var);
zval tmp;
ZVAL_COPY_VALUE(&tmp, var);
ZVAL_UNDEF(var);
zval_ptr_dtor_nogc(&tmp);
} else if (kind == ZEND_LIVE_ROPE) {
zend_string **rope = (zend_string **)var;
zend_op *last = EX(func)->op_array.opcodes + op_num;
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