[FFmpeg-devel] [PATCH 5/5] avformat/mov: Fix last mfra check

[Michael Niedermayer]

Fixes: signed integer overflow: 9223372036854775360 + 536870912 cannot be represented in type 'long'
Fixes: 37940/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6095637855207424

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/mov.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 4bc42d6b20e..d816242c0b7 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -5109,7 +5109,7 @@ static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     // See if the remaining bytes are just an mfra which we can ignore.
     is_complete = offset == stream_size;
-    if (!is_complete && (pb->seekable & AVIO_SEEKABLE_NORMAL)) {
+    if (!is_complete && (pb->seekable & AVIO_SEEKABLE_NORMAL) && stream_size > 0 ) {
         int64_t ret;
         int64_t original_pos = avio_tell(pb);
         if (!c->have_read_mfra_size) {
@@ -5120,7 +5120,7 @@ static int mov_read_sidx(MOVContext *c, AVIOContext *pb, MOVAtom atom)
             if ((ret = avio_seek(pb, original_pos, SEEK_SET)) < 0)
                 return ret;
         }
-        if (offset + c->mfra_size == stream_size)
+        if (offset == stream_size - c->mfra_size)
             is_complete = 1;
     }
 
-- 
2.17.1