[FFmpeg-cvslog] avcodec/wmalosslessdec: Fixes undefined overflow in dequantization in decode_subframe()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov 29 22:45:07 2019 +0100| [53efab44a9d0971c6c12d9b3d1af855ca863c847] | committer: Michael Niedermayer

avcodec/wmalosslessdec: Fixes undefined overflow in dequantization in decode_subframe()

Fixes: signed integer overflow: 47875596 * 45 cannot be represented in type 'int'
Fixes: 19082/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5687766512041984

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=53efab44a9d0971c6c12d9b3d1af855ca863c847
---

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

diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index d4dd0ed4e3..d2f9d4a70f 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -979,7 +979,7 @@ static int decode_subframe(WmallDecodeCtx *s)
         if (s->quant_stepsize != 1)
             for (i = 0; i < s->num_channels; i++)
                 for (j = 0; j < subframe_len; j++)
-                    s->channel_residues[i][j] *= s->quant_stepsize;
+                    s->channel_residues[i][j] *= (unsigned)s->quant_stepsize;
     }
 
     /* Write to proper output buffer depending on bit-depth */