[FFmpeg-cvslog] avcodec/pictordec: Check plane value before doing value/mask computations

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb 26 20:28:00 2017 +0100| [63e400a8807dca7b0ffa3841df2e31f7419abb8d] | committer: Michael Niedermayer

avcodec/pictordec: Check plane value before doing value/mask computations

Fixes integer overflow
Fixes: 675/clusterfuzz-testcase-6722971232108544

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=63e400a8807dca7b0ffa3841df2e31f7419abb8d
---

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

diff --git a/libavcodec/pictordec.c b/libavcodec/pictordec.c
index a3d72e3..a09ee37 100644
--- a/libavcodec/pictordec.c
+++ b/libavcodec/pictordec.c
@@ -77,10 +77,10 @@ static void picmemset(PicContext *s, AVFrame *frame, int value, int run,
                 if (*y < 0) {
                    *y = s->height - 1;
                    *plane += 1;
-                   value <<= bits_per_plane;
-                   mask  <<= bits_per_plane;
                    if (*plane >= s->nb_planes)
                        return;
+                   value <<= bits_per_plane;
+                   mask  <<= bits_per_plane;
                 }
             }
         }