webrtcdatachannel: Bind to parent webrtcbin using a weak reference

The previous approach of using a simple pointer could lead to a use-after-free
in case a data-channel was created and its parent webrtcbin was disposed soon
after.

Fixes #2103

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4580>
This commit is contained in:
Philippe Normand 2023-03-12 14:55:22 +00:00 committed by Tim-Philipp Müller
parent 0161687505
commit 268ce06c78
3 changed files with 30 additions and 5 deletions

View file

@ -2543,7 +2543,7 @@ _on_sctpdec_pad_added (GstElement * sctpdec, GstPad * pad,
if (!channel) {
channel = g_object_new (WEBRTC_TYPE_DATA_CHANNEL, NULL);
channel->parent.id = stream_id;
channel->webrtcbin = webrtc;
webrtc_data_channel_set_webrtcbin (channel, webrtc);
g_signal_emit (webrtc, gst_webrtc_bin_signals[PREPARE_DATA_CHANNEL_SIGNAL],
0, channel, FALSE);
@ -7166,7 +7166,7 @@ gst_webrtc_bin_create_data_channel (GstWebRTCBin * webrtc, const gchar * label,
gst_element_sync_state_with_parent (ret->sink_bin);
ret = gst_object_ref (ret);
ret->webrtcbin = webrtc;
webrtc_data_channel_set_webrtcbin (ret, webrtc);
g_ptr_array_add (webrtc->priv->data_channels, ret);
DC_UNLOCK (webrtc);

View file

@ -51,6 +51,7 @@ typedef void (*ChannelTask) (GstWebRTCDataChannel * channel,
struct task
{
GstWebRTCBin *webrtcbin;
GstWebRTCDataChannel *channel;
ChannelTask func;
gpointer user_data;
@ -69,6 +70,7 @@ _execute_task (GstWebRTCBin * webrtc, struct task *task)
static void
_free_task (struct task *task)
{
g_object_unref (task->webrtcbin);
gst_object_unref (task->channel);
if (task->notify)
@ -80,14 +82,22 @@ static void
_channel_enqueue_task (WebRTCDataChannel * channel, ChannelTask func,
gpointer user_data, GDestroyNotify notify)
{
struct task *task = g_new0 (struct task, 1);
GstWebRTCBin *webrtcbin = NULL;
struct task *task = NULL;
webrtcbin = g_weak_ref_get (&channel->webrtcbin_weak);
if (!webrtcbin)
return;
task = g_new0 (struct task, 1);
task->webrtcbin = webrtcbin;
task->channel = gst_object_ref (channel);
task->func = func;
task->user_data = user_data;
task->notify = notify;
gst_webrtc_bin_enqueue_task (channel->webrtcbin,
gst_webrtc_bin_enqueue_task (task->webrtcbin,
(GstWebRTCBinFunc) _execute_task, task, (GDestroyNotify) _free_task,
NULL);
}
@ -1130,6 +1140,8 @@ gst_webrtc_data_channel_finalize (GObject * object)
g_clear_object (&channel->appsrc);
g_clear_object (&channel->appsink);
g_weak_ref_clear (&channel->webrtcbin_weak);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
@ -1155,6 +1167,8 @@ webrtc_data_channel_init (WebRTCDataChannel * channel)
G_LOCK (outstanding_channels_lock);
outstanding_channels = g_list_prepend (outstanding_channels, channel);
G_UNLOCK (outstanding_channels_lock);
g_weak_ref_init (&channel->webrtcbin_weak, NULL);
}
static void
@ -1204,3 +1218,10 @@ webrtc_data_channel_link_to_sctp (WebRTCDataChannel * channel,
}
}
}
void
webrtc_data_channel_set_webrtcbin (WebRTCDataChannel * channel,
GstWebRTCBin * webrtcbin)
{
g_weak_ref_set (&channel->webrtcbin_weak, webrtcbin);
}

View file

@ -51,7 +51,7 @@ struct _WebRTCDataChannel
GstElement *sink_bin;
GstElement *appsink;
GstWebRTCBin *webrtcbin;
GWeakRef webrtcbin_weak;
gboolean opened;
gulong src_probe;
GError *stored_error;
@ -72,6 +72,10 @@ G_GNUC_INTERNAL
void webrtc_data_channel_link_to_sctp (WebRTCDataChannel *channel,
WebRTCSCTPTransport *sctp_transport);
G_GNUC_INTERNAL
void webrtc_data_channel_set_webrtcbin (WebRTCDataChannel *channel,
GstWebRTCBin *webrtcbin);
G_DECLARE_FINAL_TYPE (WebRTCErrorIgnoreBin, webrtc_error_ignore_bin, WEBRTC, ERROR_IGNORE_BIN, GstBin);
G_END_DECLS