[FFmpeg-cvslog] avformat/asfdec_f: Saturate presentation time in marker

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Oct  1 00:00:28 2023 +0200| [cedb4736f568a9cc693f81b1f7c33ea2499715ab] | committer: Michael Niedermayer

avformat/asfdec_f: Saturate presentation time in marker

Fixes: signed integer overflow: -9223372036315799520 - 3873890816 cannot be represented in type 'long'
Fixes: 51896/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5009302746431488

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cedb4736f568a9cc693f81b1f7c33ea2499715ab
---

 libavformat/asfdec_f.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index 5405956467..a579c3e894 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -674,7 +674,7 @@ static int asf_read_marker(AVFormatContext *s)
 
         avio_rl64(pb);             // offset, 8 bytes
         pres_time = avio_rl64(pb); // presentation time
-        pres_time -= asf->hdr.preroll * 10000;
+        pres_time = av_sat_sub64(pres_time, asf->hdr.preroll * 10000);
         avio_rl16(pb);             // entry length
         avio_rl32(pb);             // send time
         avio_rl32(pb);             // flags