[FFmpeg-cvslog] avcodec/h266_metadata_bsf: Check if there are CodedBitstreamFragment units

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Jul 23 19:52:35 2023 +0200| [c5c719f030a209cc404754f928972a6c1a24dfef] | committer: Michael Niedermayer

avcodec/h266_metadata_bsf: Check if there are CodedBitstreamFragment units

Fixes: NULL pointer dereference
Fixes: 60269/clusterfuzz-testcase-minimized-ffmpeg_BSF_VVC_METADATA_fuzzer-5215449416335360

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c5c719f030a209cc404754f928972a6c1a24dfef
---

 libavcodec/h266_metadata_bsf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/h266_metadata_bsf.c b/libavcodec/h266_metadata_bsf.c
index c0dbf8ef96..1f0f875cfe 100644
--- a/libavcodec/h266_metadata_bsf.c
+++ b/libavcodec/h266_metadata_bsf.c
@@ -43,7 +43,7 @@ static int h266_metadata_update_fragment(AVBSFContext *bsf, AVPacket *pkt,
     int err, i;
 
     // If an AUD is present, it must be the first NAL unit.
-    if (pu->units[0].type == VVC_AUD_NUT) {
+    if (pu->nb_units && pu->units[0].type == VVC_AUD_NUT) {
         if (ctx->aud == BSF_ELEMENT_REMOVE)
             ff_cbs_delete_unit(pu, 0);
     } else if ( pkt && ctx->aud == BSF_ELEMENT_INSERT) {