[FFmpeg-cvslog] avcodec/bonk: Avoid undefined overflow in quant

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov  5 19:57:21 2022 +0100| [977028f9f4f40efcac3ec9d6c226349dd0020b90] | committer: Michael Niedermayer

avcodec/bonk: Avoid undefined overflow in quant

Fixes: signed integer overflow: -2889074 * 2048 cannot be represented in type 'int'
Fixes: 51363/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BONK_fuzzer-5660734784143360
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BONK_fuzzer-6617680050520064
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BONK_fuzzer-6743951854141440

No check is done for the overflow as this was rejected in last review, see the ML

Note: the 2nd and 3rd testcase was assigned by ossfuzz to a unrelated theora issue (48567)

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=977028f9f4f40efcac3ec9d6c226349dd0020b90
---

 libavcodec/bonk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/bonk.c b/libavcodec/bonk.c
index 5d736b1563..9e176d5477 100644
--- a/libavcodec/bonk.c
+++ b/libavcodec/bonk.c
@@ -356,7 +356,7 @@ static int bonk_decode(AVCodecContext *avctx, AVFrame *frame,
                 sample++;
             }
 
-            sample[0] = predictor_calc_error(s->k, state, s->n_taps, s->input_samples[i] * quant);
+            sample[0] = predictor_calc_error(s->k, state, s->n_taps, s->input_samples[i] * (unsigned)quant);
             sample++;
         }