[FFmpeg-cvslog] avformat/sbgdec: Check for overflow in parse_timestamp()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Jul 19 16:20:52 2020 +0200| [b6663adaae948a66574dff58923a862774663439] | committer: Michael Niedermayer

avformat/sbgdec: Check for overflow in parse_timestamp()

Fixes: signed integer overflow: 33986707200000000 + 9195561788997000192 cannot be represented in type 'long'
Fixes: 23790/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-6554232198266880

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b6663adaae948a66574dff58923a862774663439
---

 libavformat/sbgdec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/sbgdec.c b/libavformat/sbgdec.c
index de1de271bb..c11244ef3d 100644
--- a/libavformat/sbgdec.c
+++ b/libavformat/sbgdec.c
@@ -474,6 +474,8 @@ static int parse_timestamp(struct sbg_parser *p,
     while (lex_char(p, '+')) {
         if (!lex_time(p, &dt))
             return AVERROR_INVALIDDATA;
+        if (av_sat_add64(rel, dt) - dt != rel)
+            return AVERROR_INVALIDDATA;
         rel += dt;
         r = 1;
     }