From 02174790726dd20a5c73ce2002189bf240ad4fe0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= Date: Wed, 3 Mar 2021 11:31:52 +0200 Subject: [PATCH] matroskademux: Initialize track context out parameter to NULL before parsing Various error return paths don't set it to NULL and callers are only checking if the pointer is NULL. As it's allocated on the stack this usually contains random stack memory, and more often than not the memory of a previously parsed track. This then causes all kinds of memory corruptions further down the line. Thanks to Natalie Silvanovich for reporting. Fixes https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/issues/858 Part-of: Upstream-Status: Backport [ https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/commit/02174790726dd20a5c73ce2002189bf240ad4fe0?merge_request_iid=903 ] CVE: CVE-2021-3498 Signed-off-by: Chee Yang Lee --- gst/matroska/matroska-demux.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/gst/matroska/matroska-demux.c b/gst/matroska/matroska-demux.c index 4d0234743..467815986 100644 --- a/gst/matroska/matroska-demux.c +++ b/gst/matroska/matroska-demux.c @@ -692,6 +692,8 @@ gst_matroska_demux_parse_stream (GstMatroskaDemux * demux, GstEbmlRead * ebml, DEBUG_ELEMENT_START (demux, ebml, "TrackEntry"); + *dest_context = NULL; + /* start with the master */ if ((ret = gst_ebml_read_master (ebml, &id)) != GST_FLOW_OK) { DEBUG_ELEMENT_STOP (demux, ebml, "TrackEntry", ret); -- GitLab