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Fix use-after-free in StreamPollHandle when its stream is closed #23804

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nicolas-grekas wants to merge 1 commit into from
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Fix use-after-free in StreamPollHandle when its stream is closed #23804

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31 changes: 21 additions & 10 deletions ext/standard/io_poll.c
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,6 @@ struct php_io_poll_context_object {

/* Stream poll handle specific data */
typedef struct php_stream_poll_handle_data {
php_stream *stream;
zend_resource *res;
} php_stream_poll_handle_data;

Expand Down Expand Up @@ -180,16 +179,29 @@ static const char *php_io_poll_backend_type_to_name(php_poll_backend_type type)

/* Stream Poll Handle Implementation */

static php_socket_t php_stream_poll_handle_get_fd(php_poll_handle_object *handle)
static php_stream *php_stream_poll_handle_get_stream(php_poll_handle_object *handle)
{
php_stream_poll_handle_data *data = handle->handle_data;

/* The reference taken on the resource keeps it alive, but fclose() may have
* destroyed the stream it points to in the meantime. */
if (!data || !data->res || data->res->ptr == NULL) {
return NULL;
}

return (php_stream *) data->res->ptr;
}

static php_socket_t php_stream_poll_handle_get_fd(php_poll_handle_object *handle)
{
php_stream *stream = php_stream_poll_handle_get_stream(handle);
php_socket_t fd;

if (!data || !data->stream) {
if (!stream) {
return SOCK_ERR;
}

if (php_stream_cast(data->stream, PHP_STREAM_AS_FD_FOR_SELECT | PHP_STREAM_CAST_INTERNAL,
if (php_stream_cast(stream, PHP_STREAM_AS_FD_FOR_SELECT | PHP_STREAM_CAST_INTERNAL,
(void *) &fd, 1)
!= SUCCESS
|| fd == -1) {
Expand All @@ -201,8 +213,8 @@ static php_socket_t php_stream_poll_handle_get_fd(php_poll_handle_object *handle

static int php_stream_poll_handle_is_valid(php_poll_handle_object *handle)
{
php_stream_poll_handle_data *data = handle->handle_data;
return data && data->stream && !php_stream_eof(data->stream);
php_stream *stream = php_stream_poll_handle_get_stream(handle);
return stream && !php_stream_eof(stream);
}

static void php_stream_poll_handle_cleanup(php_poll_handle_object *handle)
Expand Down Expand Up @@ -454,7 +466,6 @@ PHP_METHOD(StreamPollHandle, __construct)

/* Set up stream-specific data */
php_stream_poll_handle_data *data = emalloc(sizeof(php_stream_poll_handle_data));
data->stream = stream;
data->res = stream->res;
intern->handle_data = data;

Expand All @@ -469,12 +480,12 @@ PHP_METHOD(StreamPollHandle, getStream)
php_poll_handle_object *intern = PHP_POLL_HANDLE_OBJ_FROM_ZV(getThis());
php_stream_poll_handle_data *data = intern->handle_data;

if (!data || !data->stream) {
if (!data || !data->res) {
RETURN_NULL();
}

GC_ADDREF(data->stream->res);
php_stream_to_zval(data->stream, return_value);
GC_ADDREF(data->res);
RETURN_RES(data->res);
}

PHP_METHOD(StreamPollHandle, isValid)
Expand Down
37 changes: 37 additions & 0 deletions ext/standard/tests/poll/poll_stream_handle_close_then_use.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
--TEST--
Io\Poll: StreamPollHandle operations are safe when the stream is closed first
--FILE--
<?php
require_once __DIR__ . '/poll.inc';

list($r, $w) = pt_new_socket_pair();
$ctx = pt_new_stream_poll();
$handle = new StreamPollHandle($r);
$watcher = $ctx->add($handle, [Io\Poll\Event::Read]);

fclose($r);

var_dump($handle->isValid());
var_dump(is_resource($handle->getStream()));

try {
$watcher->modifyEvents([Io\Poll\Event::Read, Io\Poll\Event::Write]);
} catch (Io\Poll\InvalidHandleException $e) {
echo $e->getMessage(), "\n";
}

echo "Events count: ", count($ctx->wait(Time\Duration::fromSeconds(0))), "\n";

$watcher->remove();
var_dump($watcher->isActive());

fclose($w);
echo "ok\n";
?>
--EXPECT--
bool(false)
bool(false)
Invalid handle for polling
Events count: 0
bool(false)
ok
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