From 487dfa9f04bb825669441476ffd683a7783d5ce9 Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Tue, 27 Jul 2021 12:00:03 -0300
Subject: [PATCH] avformat/concat: check the terminating character returned by
 av_get_token()

Don't attempt to increase the cursor pointer if it was \0.
Fixes invalid reads.

Reviewed-by: Marton Balint <cus@passwd.hu>
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavformat/concat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/concat.c b/libavformat/concat.c
index aec1f52d8e..2560811ff9 100644
--- a/libavformat/concat.c
+++ b/libavformat/concat.c
@@ -251,7 +251,8 @@ static av_cold int concatf_open(URLContext *h, const char *uri, int flags)
             err = AVERROR(ENOMEM);
             break;
         }
-        cursor++;
+        if (*cursor)
+            cursor++;
 
         if (++len == SIZE_MAX / sizeof(*nodes)) {
             av_free(node_uri);