[FFmpeg-devel] [PATCH 1/2] avformat/mvi: Check audio size for more overflows

[Michael Niedermayer]

Fixes: left shift of negative value -352256000
Fixes: 30837/clusterfuzz-testcase-minimized-ffmpeg_dem_MVI_fuzzer-5755626262888448

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/mvi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavformat/mvi.c b/libavformat/mvi.c
index 2d4b11aa32..cfdbe5d273 100644
--- a/libavformat/mvi.c
+++ b/libavformat/mvi.c
@@ -120,6 +120,10 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
         mvi->video_frame_size = (mvi->get_int)(pb);
         if (mvi->audio_size_left == 0)
             return AVERROR(EIO);
+        if (mvi->audio_size_counter + 512 > UINT64_MAX - mvi->audio_frame_size ||
+            mvi->audio_size_counter + 512 + mvi->audio_frame_size >= ((uint64_t)INT32_MAX) << MVI_FRAC_BITS)
+            return AVERROR_INVALIDDATA;
+
         count = (mvi->audio_size_counter + mvi->audio_frame_size + 512) >> MVI_FRAC_BITS;
         if (count > mvi->audio_size_left)
             count = mvi->audio_size_left;
-- 
2.17.1