[FFmpeg-devel] [PATCH 3/3] avformat/mxfdec: check number of index table entires more strictly

[Marton Balint]

Let's ignore the index table if the number of index entries does not match the
index duration (or the special AVID index entry counts).

Fixes: OOM
Fixes: 50551/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-6607795234930688

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavformat/mxfdec.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 2e61e77d67..0dc61648b1 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -1937,6 +1937,14 @@ static int mxf_compute_ptses_fake_index(MXFContext *mxf, MXFIndexTable *index_ta
             return 0;
         }
 
+        if (s->nb_index_entries != s->index_duration &&
+            s->nb_index_entries != s->index_duration + 1 &&
+            s->nb_index_entries != s->index_duration * 2 + 1) {
+            index_table->nb_ptses = 0;
+            av_log(mxf->fc, AV_LOG_ERROR, "ignoring IndexSID %d, duration does not match nb_index_entries\n", s->index_sid);
+            return 0;
+        }
+
         index_table->nb_ptses += s->index_duration;
     }
 
-- 
2.35.3