From ce920f47930d2a1df6628f026a926425f534e8d2 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Date: Mon, 9 Dec 2019 23:26:04 +0100
Subject: [PATCH] avcodec/cbs_mpeg2: Treat slices without data as invalid

They are spec-incompliant.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/cbs_mpeg2.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/cbs_mpeg2.c b/libavcodec/cbs_mpeg2.c
index 13d871cc89..0e5d08ecbf 100644
--- a/libavcodec/cbs_mpeg2.c
+++ b/libavcodec/cbs_mpeg2.c
@@ -245,6 +245,9 @@ static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx,
         if (err < 0)
             return err;
 
+        if (!get_bits_left(&gbc))
+            return AVERROR_INVALIDDATA;
+
         pos = get_bits_count(&gbc);
         len = unit->data_size;