[FFmpeg-cvslog] avformat/samidec: Sanity check pts

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sun Jan 31 17:00:38 2021 +0100| [4e08ecb7a4b8bff71b2c4af4e8145defae526285] | committer: Michael Niedermayer

avformat/samidec: Sanity check pts

Fixes: signed integer overflow: 0 - -9223372036854775808 cannot be represented in type 'long'
Fixes: 29743/clusterfuzz-testcase-minimized-ffmpeg_dem_SAMI_fuzzer-5499256859394048

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 2014b0135293c41d261757bfa1aaba51653bab8e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4e08ecb7a4b8bff71b2c4af4e8145defae526285
---

 libavformat/samidec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavformat/samidec.c b/libavformat/samidec.c
index 3070ef9bac..cf5076c7b8 100644
--- a/libavformat/samidec.c
+++ b/libavformat/samidec.c
@@ -95,6 +95,11 @@ static int sami_read_header(AVFormatContext *s)
                 const char *p = ff_smil_get_attr_ptr(buf.str, "Start");
                 sub->pos      = pos;
                 sub->pts      = p ? strtol(p, NULL, 10) : 0;
+                if (sub->pts <= INT64_MIN/2 || sub->pts >= INT64_MAX/2) {
+                    res = AVERROR_PATCHWELCOME;
+                    goto end;
+                }
+
                 sub->duration = -1;
             }
         }