Backport of:

From 09803e225de515c8881fd13ed464c23771a4d1a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Mon, 30 Sep 2024 19:19:42 +0300
Subject: [PATCH] matroskademux: Skip over zero-sized Xiph stream headers

Thanks to Antonio Morales for finding and reporting the issue.

Fixes GHSL-2024-251
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/3867

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8058>
---
 gst/matroska/matroska-ids.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/gst/matroska/matroska-ids.c
+++ b/gst/matroska/matroska-ids.c
@@ -184,8 +184,10 @@ gst_matroska_parse_xiph_stream_headers (
     if (offset + length[i] > codec_data_size)
       goto error;
 
-    hdr = gst_buffer_new_wrapped (g_memdup (p + offset, length[i]), length[i]);
-    gst_buffer_list_add (list, hdr);
+    if (length[i] > 0) {
+      hdr = gst_buffer_new_wrapped (g_memdup (p + offset, length[i]), length[i]);
+      gst_buffer_list_add (list, hdr);
+    }
 
     offset += length[i];
   }