[FFmpeg-cvslog] avcodec/motionpixels: Mask pixels to valid values

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Thu Jan 12 23:42:59 2023 +0100| [fa201297650b3e4ce0155645efe8246c5eff75e0] | committer: Michael Niedermayer

avcodec/motionpixels: Mask pixels to valid values

Fixes: out of array access
Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MOTIONPIXELS_fuzzer-6724203352555520

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 ac6eec1fc258efce219e4fccb84312a1b13a7a23)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fa201297650b3e4ce0155645efe8246c5eff75e0
---

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

diff --git a/libavcodec/motionpixels.c b/libavcodec/motionpixels.c
index b08a2f624b..07febd3c22 100644
--- a/libavcodec/motionpixels.c
+++ b/libavcodec/motionpixels.c
@@ -184,7 +184,7 @@ static YuvPixel mp_get_yuv_from_rgb(MotionPixelsContext *mp, int x, int y)
     int color;
 
     color = *(uint16_t *)&mp->frame->data[0][y * mp->frame->linesize[0] + x * 2];
-    return mp_rgb_yuv_table[color];
+    return mp_rgb_yuv_table[color & 0x7FFF];
 }
 
 static void mp_set_rgb_from_yuv(MotionPixelsContext *mp, int x, int y, const YuvPixel *p)