From 14617fa7b8e688f5688d3679c906c8cb75ff42ed Mon Sep 17 00:00:00 2001
From: Laurent Aimar <fenrir@videolan.org>
Date: Thu, 29 Sep 2011 01:04:51 +0200
Subject: [PATCH] Prevent NULL dereference when the palette is missing in the
 xan decoder.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 56ee5a9ad1b385129c40ba4773f99bc5943ae8af)
---
 libavcodec/xan.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/xan.c b/libavcodec/xan.c
index 52f3a3f64a..b90353967d 100644
--- a/libavcodec/xan.c
+++ b/libavcodec/xan.c
@@ -552,6 +552,9 @@ static int xan_decode_frame(AVCodecContext *avctx,
         }
         buf_size = buf_end - buf;
     }
+    if (s->palettes_count <= 0)
+        return AVERROR_INVALIDDATA;
+
     if ((ret = avctx->get_buffer(avctx, &s->current_frame))) {
         av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;