From: Michael Niedermayer <michael@niedermayer.cc>
Date: Tue, 14 May 2019 18:23:48 +0000 (+0200)
Subject: avcodec/pngdec: Check input space
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=c830752142bb5e052d540c429d41fb6dafe920db;p=ffmpeg

avcodec/pngdec: Check input space

Fixes: Timeout (33sec -> 78ms)
Fixes: 14668/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LSCR_fuzzer-5767073352908800

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 7fcf83e3479..5209e342db5 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -1535,6 +1535,9 @@ static int decode_frame_lscr(AVCodecContext *avctx,
     AVFrame *frame = data;
     int ret, nb_blocks, offset = 0;
 
+    if (avpkt->size < 2)
+        return AVERROR_INVALIDDATA;
+
     bytestream2_init(gb, avpkt->data, avpkt->size);
 
     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)