[FFmpeg-cvslog] avcodec/ffwavesynth: Fix integer overflow in wavesynth_synth_sample / WS_SINE

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Sep  5 17:58:53 2020 +0200| [a0da95df77a528251a326fc8b7e2ff48c60e41d0] | committer: Michael Niedermayer

avcodec/ffwavesynth: Fix integer overflow in wavesynth_synth_sample / WS_SINE

Fixes: signed integer overflow: -1429092 * -32596 cannot be represented in type 'int'
Fixes: 24419/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FFWAVESYNTH_fuzzer-5157849974702080

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a0da95df77a528251a326fc8b7e2ff48c60e41d0
---

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

diff --git a/libavcodec/ffwavesynth.c b/libavcodec/ffwavesynth.c
index 8d3ac81aef..d92bb38c45 100644
--- a/libavcodec/ffwavesynth.c
+++ b/libavcodec/ffwavesynth.c
@@ -373,7 +373,7 @@ static void wavesynth_synth_sample(struct wavesynth_context *ws, int64_t ts,
         in->amp  += in->damp;
         switch (in->type) {
             case WS_SINE:
-                val = amp * ws->sin[in->phi >> (64 - SIN_BITS)];
+                val = amp * (unsigned)ws->sin[in->phi >> (64 - SIN_BITS)];
                 in->phi  += in->dphi;
                 in->dphi += in->ddphi;
                 break;