[FFmpeg-cvslog] avcodec/midivid: Check vector index

Michael Niedermayer git at videolan.org
Mon Feb 10 00:34:02 EET 2020


ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb  9 14:53:15 2020 +0100| [b0eec1391e1daeade456698b1aee9b2d43a6f538] | committer: Michael Niedermayer

avcodec/midivid: Check vector index

Fixes: out of array read
Fixes: 20494/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MVDV_fuzzer-5681452423577600

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b0eec1391e1daeade456698b1aee9b2d43a6f538
---

 libavcodec/midivid.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/midivid.c b/libavcodec/midivid.c
index bb5105bd57..8d4c3b369e 100644
--- a/libavcodec/midivid.c
+++ b/libavcodec/midivid.c
@@ -126,6 +126,8 @@ static int decode_mvdv(MidiVidContext *s, AVCodecContext *avctx, AVFrame *frame)
                 idx9bits--;
                 idx = bytestream2_get_byte(gb) | (((idx9val >> (7 - idx9bits)) & 1) << 8);
             }
+            if (idx >= nb_vectors)
+                return AVERROR_INVALIDDATA;
 
             dsty[x  +frame->linesize[0]] = vec[idx * 12 + 0];
             dsty[x+1+frame->linesize[0]] = vec[idx * 12 + 3];



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