[FFmpeg-devel] [PATCH 02/13] avformat/mxfdec: Check run_in to fit in int and be valid

[Michael Niedermayer]

Fixes: signed integer overflow: 9223372036854775807 - -2146905566 cannot be represented in type 'long'
Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_MXF_fuzzer-6570996594769920

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/mxfdec.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index e63e803aa56..da81fea3bc1 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -3681,6 +3681,7 @@ static int mxf_read_header(AVFormatContext *s)
     KLVPacket klv;
     int64_t essence_offset = 0;
     int ret;
+    int64_t run_in;
 
     mxf->last_forward_tell = INT64_MAX;
 
@@ -3690,7 +3691,10 @@ static int mxf_read_header(AVFormatContext *s)
     }
     avio_seek(s->pb, -14, SEEK_CUR);
     mxf->fc = s;
-    mxf->run_in = avio_tell(s->pb);
+    run_in = avio_tell(s->pb);
+    if (run_in < 0 || run_in != (int)run_in)
+        return AVERROR_INVALIDDATA;
+    mxf->run_in = run_in;
 
     mxf_read_random_index_pack(s);
 
-- 
2.17.1