[FFmpeg-cvslog] avcodec/wmalosslessdec: Fix 2 overflows in mclms

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Wed Nov 20 22:05:40 2019 +0100| [45eef1be3a42d9fb548d39a27af00343ff412866] | committer: Michael Niedermayer

avcodec/wmalosslessdec: Fix 2 overflows in mclms

Fixes: signed integer overflow: 2038337026 + 109343477 cannot be represented in type 'int'
Fixes: 18886/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5673660505653248

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 92455c8c65c403ea696cb8c63d474d386d631bbd)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=45eef1be3a42d9fb548d39a27af00343ff412866
---

 libavcodec/wmalosslessdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index 2b064e5f76..8fb08fb36d 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -625,7 +625,7 @@ static void mclms_update(WmallDecodeCtx *s, int icoef, int *pred)
     int range        = 1 << (s->bits_per_sample - 1);
 
     for (ich = 0; ich < num_channels; ich++) {
-        pred_error = s->channel_residues[ich][icoef] - pred[ich];
+        pred_error = s->channel_residues[ich][icoef] - (unsigned)pred[ich];
         if (pred_error > 0) {
             for (i = 0; i < order * num_channels; i++)
                 s->mclms_coeffs[i + ich * order * num_channels] +=
@@ -677,7 +677,7 @@ static void mclms_predict(WmallDecodeCtx *s, int icoef, int *pred)
                          s->mclms_coeffs_cur[i + num_channels * ich];
         pred[ich] += (1 << s->mclms_scaling) >> 1;
         pred[ich] >>= s->mclms_scaling;
-        s->channel_residues[ich][icoef] += pred[ich];
+        s->channel_residues[ich][icoef] += (unsigned)pred[ich];
     }
 }