[FFmpeg-cvslog] avcodec/shorten: Fix multiple integer overflows

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Tue Jun  5 13:19:35 2018 +0200| [081874a050d1cdb081df7feb7e6cc99a7d25641e] | committer: Michael Niedermayer

avcodec/shorten: Fix multiple integer overflows

Fixes: signed integer overflow: 3 * 1006632960 cannot be represented in type 'int'
Fixes: 8278/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5692857166856192

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 f2abd36b3863188894fd21964c662b6c17268bfb)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=081874a050d1cdb081df7feb7e6cc99a7d25641e
---

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

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 0bd3e1e5f7..18a12d0b97 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -389,7 +389,7 @@ static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
     for (i = 0; i < s->blocksize; i++) {
         sum = init_sum;
         for (j = 0; j < pred_order; j++)
-            sum += coeffs[j] * s->decoded[channel][i - j - 1];
+            sum += coeffs[j] * (unsigned)s->decoded[channel][i - j - 1];
         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) +
                                  (sum >> qshift);
     }
@@ -700,7 +700,7 @@ static int shorten_decode_frame(AVCodecContext *avctx, void *data,
 
             /* update means with info from the current block */
             if (s->nmean > 0) {
-                int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
+                int64_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
                 for (i = 0; i < s->blocksize; i++)
                     sum += s->decoded[channel][i];