[FFmpeg-cvslog] avformat/bfi: check nframes

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Fri Apr 23 19:33:58 2021 +0200| [6d86416c92c127de23f5d62fa5d40cf3613c4b14] | committer: Michael Niedermayer

avformat/bfi: check nframes

Fixes: signed integer overflow: -2147483648 - 1 cannot be represented in type 'int'
Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_BFI_fuzzer-6737028768202752

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 b4e77dfca1c2970446f79277034d8e60c3fe3f4e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6d86416c92c127de23f5d62fa5d40cf3613c4b14
---

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

diff --git a/libavformat/bfi.c b/libavformat/bfi.c
index 2dab986f3a..f9e0bb2e30 100644
--- a/libavformat/bfi.c
+++ b/libavformat/bfi.c
@@ -73,6 +73,8 @@ static int bfi_read_header(AVFormatContext * s)
         return AVERROR_INVALIDDATA;
 
     bfi->nframes           = avio_rl32(pb);
+    if (bfi->nframes < 0)
+        return AVERROR_INVALIDDATA;
     avio_rl32(pb);
     avio_rl32(pb);
     avio_rl32(pb);