From 668643b9239c70b777aea322eab411ebc960d9a0 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 4 Sep 2013 08:55:17 +0200
Subject: [PATCH] matroskadec: check av_strdup() when setting defaults

---
 libavformat/matroskadec.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index dc32fd1cc1..e6c9adf547 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -851,7 +851,13 @@ static int ebml_parse_nest(MatroskaDemuxContext *matroska, EbmlSyntax *syntax,
             break;
         case EBML_STR:
         case EBML_UTF8:
-            *(char    **)((char *)data+syntax[i].data_offset) = av_strdup(syntax[i].def.s);
+            // the default may be NULL
+            if (syntax[i].def.s) {
+                uint8_t **dst = (uint8_t**)((uint8_t*)data + syntax[i].data_offset);
+                *dst = av_strdup(syntax[i].def.s);
+                if (!*dst)
+                    return AVERROR(ENOMEM);
+            }
             break;
         }