[FFmpeg-cvslog] avcodec/jpeg2000dec: Check atom_size in jp2_find_codestream()

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sun Jan 31 16:54:06 2021 +0100| [186df3419c0a2e9b966333b39aa806e1df0afd5d] | committer: Michael Niedermayer

avcodec/jpeg2000dec: Check atom_size in jp2_find_codestream()

Fixes: Infinite loop
Fixes: 29722/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-6412228041506816

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 2a2082a41bca9dbb22c45288972f2da309443cf8)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=186df3419c0a2e9b966333b39aa806e1df0afd5d
---

 libavcodec/jpeg2000dec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index ab36009a2d..fad614e03a 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -2207,8 +2207,12 @@ static int jp2_find_codestream(Jpeg2000DecoderContext *s)
                 return 0;
             }
             atom_size = bytestream2_get_be32u(&s->g);
+            if (atom_size < 16 || (int64_t)bytestream2_tell(&s->g) + atom_size - 16 > INT_MAX)
+                return AVERROR_INVALIDDATA;
             atom_end  = bytestream2_tell(&s->g) + atom_size - 16;
         } else {
+            if (atom_size <  8 || (int64_t)bytestream2_tell(&s->g) + atom_size -  8 > INT_MAX)
+                return AVERROR_INVALIDDATA;
             atom_end  = bytestream2_tell(&s->g) + atom_size -  8;
         }