[FFmpeg-cvslog] avcodec/vvc/dec: fix possible null-pointer dereference

[Marvin Scholz]

ffmpeg | branch: master | Marvin Scholz <epirat07-at-gmail.com at ffmpeg.org> | Wed Jun 11 19:53:29 2025 +0200| [3d7668dae12fc07a49ba19875ba4d32a4ff46289] | committer: Nuo Mi

avcodec/vvc/dec: fix possible null-pointer dereference

When checking for filmgrain here, needs_fg can be true even when
film_grain_characteristics is NULL (when aom_film_grain.enable is true),
therefore this check could end up dereferencing film_grain_characteristics
even though it is NULL.

Fix CID 1648347

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3d7668dae12fc07a49ba19875ba4d32a4ff46289
---

 libavcodec/vvc/dec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vvc/dec.c b/libavcodec/vvc/dec.c
index aba31b94fe..7930d64a05 100644
--- a/libavcodec/vvc/dec.c
+++ b/libavcodec/vvc/dec.c
@@ -770,7 +770,8 @@ static int check_film_grain(VVCContext *s, VVCFrameContext *fc)
         !s->avctx->hwaccel;
 
     if (fc->ref->needs_fg &&
-        (fc->sei.common.film_grain_characteristics->present &&
+        (fc->sei.common.film_grain_characteristics &&
+         fc->sei.common.film_grain_characteristics->present &&
             !ff_h274_film_grain_params_supported(fc->sei.common.film_grain_characteristics->model_id,
                 fc->ref->frame->format) ||
             !av_film_grain_params_select(fc->ref->frame))) {