[FFmpeg-cvslog] avcodec/pictordec: Do not read more than nb_planes

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Feb 20 12:31:43 2017 +0100| [01d196a67dc55eb01cf3e06d6338c5d096a29b1c] | committer: Michael Niedermayer

avcodec/pictordec: Do not read more than nb_planes

Fixes undefined behavior
Fixes: 622/clusterfuzz-testcase-5745722022428672

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=01d196a67dc55eb01cf3e06d6338c5d096a29b1c
---

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

diff --git a/libavcodec/pictordec.c b/libavcodec/pictordec.c
index 0cfc785..a3d72e3 100644
--- a/libavcodec/pictordec.c
+++ b/libavcodec/pictordec.c
@@ -80,7 +80,7 @@ static void picmemset(PicContext *s, AVFrame *frame, int value, int run,
                    value <<= bits_per_plane;
                    mask  <<= bits_per_plane;
                    if (*plane >= s->nb_planes)
-                       break;
+                       return;
                 }
             }
         }
@@ -236,7 +236,7 @@ static int decode_frame(AVCodecContext *avctx,
             }
         }
 
-        if (x < avctx->width) {
+        if (plane < s->nb_planes && x < avctx->width) {
             int run = (y + 1) * avctx->width - x;
             if (bits_per_plane == 8)
                 picmemset_8bpp(s, frame, val, run, &x, &y);