[FFmpeg-cvslog] avcodec/shorten: Fix integer overflow in residual/LPC combination

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sun Aug 12 22:55:59 2018 +0200| [bb070fc4684dd80a82983469ccf685dfeb3e1c4e] | committer: Michael Niedermayer

avcodec/shorten: Fix integer overflow in residual/LPC combination

Fixes: signed integer overflow: -540538872 + -2012739576 cannot be represented in type 'int'
Fixes: 9255/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5758630052757504

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 db7e9082e1a1479c6a8844f7adf77eae03cc2aa7)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bb070fc4684dd80a82983469ccf685dfeb3e1c4e
---

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

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 047fb05a9b..de2be90e77 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -315,7 +315,7 @@ static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
         for (j = 0; j < pred_order; j++)
             sum += coeffs[j] * (unsigned)s->decoded[channel][i - j - 1];
         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) +
-                                 (sum >> qshift);
+                                 (unsigned)(sum >> qshift);
     }
 
     /* add offset to current samples */