mpegtsmux: Don't create streams with reserved PID

There are quite a few reserved PID in the various MPEG-TS (and derivate)
specifications which we should definitely not use. Those PID have a certain
meaning and purpose.

Furthermore, a lot of the code in the muxer implementation also makes assumption
on the purpose of streams based on their PID.

Therefore, when requesting a pad with a specific PID, make sure it is not a
restricted PID.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1620>

1 files changed, 11 insertions, 0 deletions

diff --git a/gst/mpegtsmux/gstbasetsmux.c b/gst/mpegtsmux/gstbasetsmux.c
index d2a73dd4f..045c34ddb 100644
--- a/gst/mpegtsmux/gstbasetsmux.c
+++ b/gst/mpegtsmux/gstbasetsmux.c
@@ -1268,6 +1268,10 @@ gst_base_ts_mux_request_new_pad (GstElement * element, GstPadTemplate * templ,
   if (name != NULL && sscanf (name, "sink_%d", &pid) == 1) {
     if (tsmux_find_stream (mux->tsmux, pid))
       goto stream_exists;
+    /* Make sure we don't use reserved PID.
+     * FIXME : This should be extended to other variants (ex: ATSC) reserved PID */
+    if (pid < TSMUX_START_ES_PID)
+      goto invalid_stream_pid;
   } else {
     pid = tsmux_get_new_pid (mux->tsmux);
   }
@@ -1288,6 +1292,13 @@ stream_exists:
         (NULL));
     return NULL;
   }
+
+invalid_stream_pid:
+  {
+    GST_ELEMENT_ERROR (element, STREAM, MUX,
+        ("Invalid Elementary stream PID (< 0x40)"), (NULL));
+    return NULL;
+  }
 }
 
 static void