gst: Initialize optional event/message fields when parsing

These might not exist inside the structure and then we would potentially
keep around uninitialized memory from the caller in the out parameter.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/887>

2 files changed, 12 insertions, 1 deletions

diff --git a/gst/gstevent.c b/gst/gstevent.c
index 9ace25a7bd..225ed3bf54 100644
--- a/gst/gstevent.c
+++ b/gst/gstevent.c
@@ -863,6 +863,10 @@ gst_event_parse_gap_flags (GstEvent * event, GstGapFlags * flags)
   g_return_if_fail (event != NULL);
   g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_GAP);
 
+  /* Initialize to 0 for GAP events that don't have the field set */
+  if (flags)
+    *flags = 0;
+
   gst_structure_id_get (GST_EVENT_STRUCTURE (event),
       GST_QUARK (GAP_FLAGS), GST_TYPE_GAP_FLAGS, flags, NULL);
 }
@@ -1478,6 +1482,9 @@ gst_event_parse_seek_trickmode_interval (GstEvent * event,
   g_return_if_fail (interval != NULL);
   g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_SEEK);
 
+  if (interval)
+    *interval = GST_CLOCK_TIME_NONE;
+
   gst_structure_id_get (GST_EVENT_STRUCTURE (event),
       GST_QUARK (TRICKMODE_INTERVAL), GST_TYPE_CLOCK_TIME, interval, NULL);
 }
@@ -1814,10 +1821,10 @@ gst_event_parse_stream (GstEvent * event, GstStream ** stream)
   g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
 
   if (stream) {
+    *stream = NULL;
     gst_structure_id_get (GST_EVENT_STRUCTURE (event),
         GST_QUARK (STREAM), GST_TYPE_STREAM, stream, NULL);
   }
-
 }
 
 /**
@@ -1852,6 +1859,7 @@ gst_event_parse_stream_flags (GstEvent * event, GstStreamFlags * flags)
   g_return_if_fail (GST_EVENT_TYPE (event) == GST_EVENT_STREAM_START);
 
   if (flags) {
+    *flags = 0;
     gst_structure_id_get (GST_EVENT_STRUCTURE (event),
         GST_QUARK (FLAGS), GST_TYPE_STREAM_FLAGS, flags, NULL);
   }
@@ -1902,6 +1910,7 @@ gst_event_parse_group_id (GstEvent * event, guint * group_id)
       FALSE);
 
   if (group_id) {
+    *group_id = 0;
     return gst_structure_id_get (GST_EVENT_STRUCTURE (event),
         GST_QUARK (GROUP_ID), G_TYPE_UINT, group_id, NULL);
   }
diff --git a/gst/gstmessage.c b/gst/gstmessage.c
index f3f200709e..45d4f4f010 100644
--- a/gst/gstmessage.c
+++ b/gst/gstmessage.c
@@ -2472,6 +2472,8 @@ gst_message_parse_group_id (GstMessage * message, guint * group_id)
   if (!group_id)
     return TRUE;
 
+  *group_id = 0;
+
   structure = GST_MESSAGE_STRUCTURE (message);
 
   v = gst_structure_id_get_value (structure, GST_QUARK (GROUP_ID));