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Fix GH-16321: UAF in list_entry_destructor when resource dtor adds references #21686

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Fix GH-16321: UAF in list_entry_destructor when resource dtor adds references #21686

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8 changes: 7 additions & 1 deletion Zend/zend_list.c
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Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,9 @@ ZEND_API zend_result ZEND_FASTCALL zend_list_delete(zend_resource *res)
ZEND_API void ZEND_FASTCALL zend_list_free(zend_resource *res)
{
ZEND_ASSERT(GC_REFCOUNT(res) == 0);
zend_hash_index_del(&EG(regular_list), res->handle);
if (zend_hash_index_del(&EG(regular_list), res->handle) == FAILURE) {
efree_size(res, sizeof(zend_resource));
}
}

static void zend_resource_dtor(zend_resource *res)
Expand Down Expand Up @@ -177,7 +179,11 @@ void list_entry_destructor(zval *zv)

ZVAL_UNDEF(zv);
if (res->type >= 0) {
GC_ADDREF(res);
zend_resource_dtor(res);
if (GC_DELREF(res) != 0) {
return;
}
}
efree_size(res, sizeof(zend_resource));
}
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32 changes: 32 additions & 0 deletions ext/standard/tests/filters/gh16321.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
--TEST--
GH-16321 (UAF when stream filter throws during stream close)
--FILE--
<?php
class TestFilter extends php_user_filter {
function filter($in, $out, &$consumed, $closing): int {
stream_bucket_new($this->stream, "42");
return PSFS_ERR_FATAL;
}
}

stream_filter_register("test_filter", "TestFilter");

function test() {
$stream = fopen('php://memory', 'wb+');
fwrite($stream, "data");
fseek($stream, 0, SEEK_SET);
stream_filter_append($stream, "test_filter");
stream_get_contents($stream);
}

test();
?>
--EXPECTF--
Warning: stream_get_contents(): Unprocessed filter buckets remaining on input brigade in %s on line %d

Fatal error: Uncaught TypeError: stream_bucket_new(): Argument #1 ($stream) must be an open stream resource in %s:%d
Stack trace:
#0 %s(%d): stream_bucket_new(Resource id #%d, '42')
#1 %s(%d): TestFilter->filter(Resource id #%d, Resource id #%d, 0, true)
#2 {main}
thrown in %s on line %d
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