[FFmpeg-cvslog] avformat/mov: Check samplesize and offset to avoid integer overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Mon Feb 20 19:19:32 2023 +0100| [26a98f0dba6cd7ee95a1ae9342acb67a4719cd92] | committer: Michael Niedermayer

avformat/mov: Check samplesize and offset to avoid integer overflow

Fixes: signed integer overflow: 9223372036854775584 + 536870912 cannot be represented in type 'long'
Fixes: 55844/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-510613920664780

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 53c1f5c2e28e54ea8174b196d5cf4a158907395a)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=26a98f0dba6cd7ee95a1ae9342acb67a4719cd92
---

 libavformat/mov.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 8698b85e92..fd82ca460b 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -3899,6 +3899,13 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
                 if (keyframe)
                     distance = 0;
                 sample_size = sc->stsz_sample_size > 0 ? sc->stsz_sample_size : sc->sample_sizes[current_sample];
+                if (current_offset > INT64_MAX - sample_size) {
+                    av_log(mov->fc, AV_LOG_ERROR, "Current offset %"PRId64" or sample size %u is too large\n",
+                           current_offset,
+                           sample_size);
+                    return;
+                }
+
                 if (sc->pseudo_stream_id == -1 ||
                    sc->stsc_data[stsc_index].id - 1 == sc->pseudo_stream_id) {
                     AVIndexEntry *e;