[FFmpeg-cvslog] avformat/mxfdec: Check index_edit_rate

[Michael Niedermayer]

ffmpeg | branch: release/6.0 | Michael Niedermayer <michael at niedermayer.cc> | Thu Apr  4 00:38:20 2024 +0200| [fe5946684aa6d117dccbada05365338654768cbe] | committer: Michael Niedermayer

avformat/mxfdec: Check index_edit_rate

Fixes: Assertion b >=0 failed at libavutil/mathematics.c:62
Fixes: 67811/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-5108429687422976

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 ed49391961999f028e0bc55767d0eef6eeb15e49)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fe5946684aa6d117dccbada05365338654768cbe
---

 libavformat/mxfdec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 540d6dbf3d..b09b4086ac 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -1264,6 +1264,9 @@ static int mxf_read_index_table_segment(void *arg, AVIOContext *pb, int tag, int
     case 0x3F0B:
         segment->index_edit_rate.num = avio_rb32(pb);
         segment->index_edit_rate.den = avio_rb32(pb);
+        if (segment->index_edit_rate.num <= 0 ||
+            segment->index_edit_rate.den <= 0)
+            return AVERROR_INVALIDDATA;
         av_log(NULL, AV_LOG_TRACE, "IndexEditRate %d/%d\n", segment->index_edit_rate.num,
                 segment->index_edit_rate.den);
         break;