From e7011a0ca6548e12b458259c51e305e8a4d5ae2e Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Fri, 6 Dec 2019 00:07:17 +0100
Subject: [PATCH] avcodec/mvha: Check remaining space when reading VLC table
 probabilities

Fixes: Infinite loop
Fixes: 19183/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MVHA_fuzzer-5666216765292544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/mvha.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/mvha.c b/libavcodec/mvha.c
index 4b03a79283..c270063b1c 100644
--- a/libavcodec/mvha.c
+++ b/libavcodec/mvha.c
@@ -203,6 +203,9 @@ static int decode_frame(AVCodecContext *avctx,
         for (int i = 0; i < s->nb_symbols; symbol++) {
             int prob;
 
+            if (get_bits_left(gb) < 4)
+                return AVERROR_INVALIDDATA;
+
             if (get_bits1(gb)) {
                 prob = get_bits(gb, 12);
             } else {