[FFmpeg-cvslog] avformat/mov: check offset for overflow in mov_probe()

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Sun Apr  4 21:01:46 2021 +0200| [d22550dd61003ffefc1a7738b2c14916083116a9] | committer: Michael Niedermayer

avformat/mov: check offset for overflow in mov_probe()

Fixes: Invalid read of size 4
Fixes: ASAN_Deadlysignal.zip

Found-by: Hardik Shah <hardik05 at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 0f6a3405e8987ad761a2d9139fdc95bbb6a61118)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d22550dd61003ffefc1a7738b2c14916083116a9
---

 libavformat/mov.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 50234f3b5f..38a70589be 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7122,7 +7122,7 @@ static int mov_probe(const AVProbeData *p)
         int64_t size;
         int minsize = 8;
         /* ignore invalid offset */
-        if ((offset + 8) > (unsigned int)p->buf_size)
+        if ((offset + 8ULL) > (unsigned int)p->buf_size)
             break;
         size = AV_RB32(p->buf + offset);
         if (size == 1 && offset + 16 <= (unsigned int)p->buf_size) {
@@ -7169,6 +7169,8 @@ static int mov_probe(const AVProbeData *p)
             score  = FFMAX(score, AVPROBE_SCORE_EXTENSION);
             break;
         }
+        if (size > INT64_MAX - offset)
+            break;
         offset += size;
     }
     if (score > AVPROBE_SCORE_MAX - 50 && moov_offset != -1) {