From ebb0ca3d70465ab6d369a66b2ef43bb059705db8 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Sat, 23 May 2015 00:23:05 +0200
Subject: [PATCH] avformat/nutdec: Check X in 2nd branch of index reading

Prevents read of uninitialized variable

Based on patch by: Andreas Cadhalpun <andreas.cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
 libavformat/nutdec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c
index f1cece8967..ad9053cf73 100644
--- a/libavformat/nutdec.c
+++ b/libavformat/nutdec.c
@@ -720,6 +720,10 @@ static int find_and_decode_index(NUTContext *nut)
                     has_keyframe[n++] = flag;
                 has_keyframe[n++] = !flag;
             } else {
+                if (x <= 1) {
+                    av_log(s, AV_LOG_ERROR, "index: x %"PRIu64" is invalid\n", x);
+                    goto fail;
+                }
                 while (x != 1) {
                     if (n >= syncpoint_count + 1) {
                         av_log(s, AV_LOG_ERROR, "index overflow B\n");