[FFmpeg-cvslog] avformat/mov: Check for EOF in mov_read_glbl()

[Michael Niedermayer]

ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Sat Dec  4 20:11:35 2021 +0100| [c63fed42930e40b08034c7b0db1139d2739771a8] | committer: Michael Niedermayer

avformat/mov: Check for EOF in mov_read_glbl()

Fixes: Infinite loop
Fixes: 41351/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5433895854669824

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 59b4e7cbd87889c0bac710ac7f62782b637419a1)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c63fed42930e40b08034c7b0db1139d2739771a8
---

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

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 3ec6e91098..aeb3cbbc7e 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1700,6 +1700,8 @@ static int mov_read_glbl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         // wrap a whole fiel atom inside of a glbl atom.
         unsigned size = avio_rb32(pb);
         unsigned type = avio_rl32(pb);
+        if (avio_feof(pb))
+            return AVERROR_INVALIDDATA;
         avio_seek(pb, -8, SEEK_CUR);
         if (type == MKTAG('f','i','e','l') && size == atom.size)
             return mov_read_default(c, pb, atom);