[FFmpeg-cvslog] avformat/av1dec: Check bits left before get_leb128()

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Aug  6 18:18:15 2024 +0200| [6996e1238e80b23caf05428dcbdd065fbd70ff10] | committer: Michael Niedermayer

avformat/av1dec: Check bits left before get_leb128()

Fixes: use of uninitialized value
Fixes: 70872/clusterfuzz-testcase-minimized-ffmpeg_dem_OBU_fuzzer-6005782487826432

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6996e1238e80b23caf05428dcbdd065fbd70ff10
---

 libavformat/av1dec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavformat/av1dec.c b/libavformat/av1dec.c
index 3363003b18..a5b620a0ab 100644
--- a/libavformat/av1dec.c
+++ b/libavformat/av1dec.c
@@ -326,6 +326,9 @@ static int read_obu_with_size(const uint8_t *buf, int buf_size, int64_t *obu_siz
         skip_bits(&gb, 3);  // extension_header_reserved_3bits
     }
 
+    if (get_bits_left(&gb) < 8)
+        return AVERROR_INVALIDDATA;
+
     *obu_size  = get_leb128(&gb);
     if (*obu_size > INT_MAX)
         return AVERROR_INVALIDDATA;