[FFmpeg-cvslog] avcodec/h264_slice: Fix signed integer overflow

[Michael Niedermayer]

ffmpeg | branch: release/3.1 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jul  5 00:05:11 2017 +0200| [965f15551fb07f1c0be37fd369b0ab4462da0965] | committer: Michael Niedermayer

avcodec/h264_slice: Fix signed integer overflow

Fixes: runtime error: signed integer overflow: 26 + 2147483644 cannot be represented in type 'int'
Fixes: 2456/clusterfuzz-testcase-minimized-4822695051001856

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 7592d97f10134422d4509ab1287796af70e003ba)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=965f15551fb07f1c0be37fd369b0ab4462da0965
---

 libavcodec/h264_slice.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/h264_slice.c b/libavcodec/h264_slice.c
index 474400ba2f..d3f1360359 100644
--- a/libavcodec/h264_slice.c
+++ b/libavcodec/h264_slice.c
@@ -1667,7 +1667,7 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl)
     }
 
     sl->last_qscale_diff = 0;
-    tmp = pps->init_qp + get_se_golomb(&sl->gb);
+    tmp = pps->init_qp + (unsigned)get_se_golomb(&sl->gb);
     if (tmp > 51 + 6 * (sps->bit_depth_luma - 8)) {
         av_log(h->avctx, AV_LOG_ERROR, "QP %u out of range\n", tmp);
         return AVERROR_INVALIDDATA;