[FFmpeg-cvslog] avcodec/vmdaudio: Check chunk counts to avoid integer overflow

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov  8 17:28:27 2019 +0100| [47d963335eb2c36c0e6615d7971c762458e813dd] | committer: Michael Niedermayer

avcodec/vmdaudio: Check chunk counts to avoid integer overflow

Fixes: signed integer overflow: 4 * 538976288 cannot be represented in type 'int'
Fixes: 18622/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VMDAUDIO_fuzzer-5092166174507008

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=47d963335eb2c36c0e6615d7971c762458e813dd
---

 libavcodec/vmdaudio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/vmdaudio.c b/libavcodec/vmdaudio.c
index e8c8a064c7..c7826fa3ce 100644
--- a/libavcodec/vmdaudio.c
+++ b/libavcodec/vmdaudio.c
@@ -179,6 +179,9 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
     /* drop incomplete chunks */
     buf_size     = audio_chunks * s->chunk_size;
 
+    if (silent_chunks + audio_chunks >= INT_MAX / avctx->block_align)
+        return AVERROR_INVALIDDATA;
+
     /* get output buffer */
     frame->nb_samples = ((silent_chunks + audio_chunks) * avctx->block_align) /
                         avctx->channels;