[FFmpeg-cvslog] avcodec/agm: Include block size in the MV check for flags == 3

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Dec 16 23:09:04 2019 +0100| [1f2096945709a32315da740691b5716da55893c3] | committer: Michael Niedermayer

avcodec/agm: Include block size in the MV check for flags == 3

Fixes: out of array read
Fixes: 19331/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5644115983466496

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=1f2096945709a32315da740691b5716da55893c3
---

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

diff --git a/libavcodec/agm.c b/libavcodec/agm.c
index 628f324913..80f4697ee5 100644
--- a/libavcodec/agm.c
+++ b/libavcodec/agm.c
@@ -423,8 +423,8 @@ static int decode_inter_plane(AGMContext *s, GetBitContext *gb, int size,
                 int map = s->map[x];
 
                 if (orig_mv_x >= -32) {
-                    if (y * 8 + mv_y < 0 || y * 8 + mv_y >= h ||
-                        x * 8 + mv_x < 0 || x * 8 + mv_x >= w)
+                    if (y * 8 + mv_y < 0 || y * 8 + mv_y + 8 >= h ||
+                        x * 8 + mv_x < 0 || x * 8 + mv_x + 8 >= w)
                         return AVERROR_INVALIDDATA;
 
                     copy_block8(frame->data[plane] + (s->blocks_h - 1 - y) * 8 * frame->linesize[plane] + x * 8,