From 279e3aaa14daba6b7a37d75f3fb6e29c732d123f Mon Sep 17 00:00:00 2001
From: Luca Barbato <lu_zero@gentoo.org>
Date: Mon, 17 Apr 2017 14:10:52 +0000
Subject: [PATCH] flv: Validate the packet size

Size can be negative at that point.

Bug-Id: 1041
CC: libav-stable@libav.org
---
 libavformat/flvdec.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 693c859ebf..1b29740f41 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -912,6 +912,12 @@ skip:
         st->codecpar->codec_id == AV_CODEC_ID_H264) {
         int type = avio_r8(s->pb);
         size--;
+
+        if (size < 0) {
+            ret = AVERROR_INVALIDDATA;
+            goto leave;
+        }
+
         if (st->codecpar->codec_id == AV_CODEC_ID_H264) {
             // sign extension
             int32_t cts = (avio_rb24(s->pb) + 0xff800000) ^ 0xff800000;