[FFmpeg-cvslog] avcodec/takdec: Fix integer overflows in decode_subframe()

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Fri Sep 22 20:45:26 2017 +0200| [a0f854b5ffbd8ccb0d6f7caa666abd02efc1c9e3] | committer: Michael Niedermayer

avcodec/takdec: Fix integer overflows in decode_subframe()

Fixes: runtime error: signed integer overflow: -1562477869 + -691460395 cannot be represented in type 'int'
Fixes: 3196/clusterfuzz-testcase-minimized-4528307146063872

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 3dabb9c69db114b1f30c30e0a2788cffc50bac40)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a0f854b5ffbd8ccb0d6f7caa666abd02efc1c9e3
---

 libavcodec/takdec.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavcodec/takdec.c b/libavcodec/takdec.c
index 4ace0d9a78..e34d773056 100644
--- a/libavcodec/takdec.c
+++ b/libavcodec/takdec.c
@@ -472,10 +472,10 @@ static int decode_subframe(TAKDecContext *s, int32_t *decoded,
                 v += (unsigned)s->adsp.scalarproduct_int16(&s->residues[i], s->filter,
                                                  filter_order & -16);
             for (j = filter_order & -16; j < filter_order; j += 4) {
-                v += s->residues[i + j + 3] * s->filter[j + 3] +
-                     s->residues[i + j + 2] * s->filter[j + 2] +
-                     s->residues[i + j + 1] * s->filter[j + 1] +
-                     s->residues[i + j    ] * s->filter[j    ];
+                v += s->residues[i + j + 3] * (unsigned)s->filter[j + 3] +
+                     s->residues[i + j + 2] * (unsigned)s->filter[j + 2] +
+                     s->residues[i + j + 1] * (unsigned)s->filter[j + 1] +
+                     s->residues[i + j    ] * (unsigned)s->filter[j    ];
             }
             v = (av_clip_intp2(v >> filter_quant, 13) * (1 << dshift)) - (unsigned)*decoded;
             *decoded++ = v;