[FFmpeg-cvslog] avcodec/h264_cabac: Tighten allowed coeff_abs range

[Michael Niedermayer]

ffmpeg | branch: release/3.3 | Michael Niedermayer <michael at niedermayer.cc> | Wed Feb 14 00:32:30 2018 +0100| [878fc42a906d13cd6a78b0820eed75f4fd8e26e5] | committer: Michael Niedermayer

avcodec/h264_cabac: Tighten allowed coeff_abs range

Fixes: integer overflows
Reported-by: "Xiaohan Wang (王消寒)" <xhwang at chromium.org>

Based on limits in "8.5 Transform coefficient decoding process and picture
construction process prior to deblocking  filter process"

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit f26a63c4ee1bdbe21d7ab462cd66f8ba20b14244)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=878fc42a906d13cd6a78b0820eed75f4fd8e26e5
---

 libavcodec/h264_cabac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c
index 04b77f284f..1e05c04680 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -1735,7 +1735,7 @@ decode_cabac_residual_internal(const H264Context *h, H264SliceContext *sl,
 \
             if( coeff_abs >= 15 ) { \
                 int j = 0; \
-                while (get_cabac_bypass(CC) && j < 30) { \
+                while (get_cabac_bypass(CC) && j < 16+7) { \
                     j++; \
                 } \
 \