[FFmpeg-cvslog] avformat/wtvdec: Check length of read mpeg2_descriptor

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Wed Aug  7 00:18:53 2024 +0200| [f09b8df1d06ed427c3f60d0a77e767778fa6b8e5] | committer: Michael Niedermayer

avformat/wtvdec: Check length of read mpeg2_descriptor

Fixes: Use of uninitialized value
Fixes: 70900/clusterfuzz-testcase-minimized-ffmpeg_dem_WTV_fuzzer-6286909377150976

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Peter Ross <pross at xvid.org>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit c390234da2e3c7a8884f5592f0b9b4928c482b3e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f09b8df1d06ed427c3f60d0a77e767778fa6b8e5
---

 libavformat/wtvdec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/wtvdec.c b/libavformat/wtvdec.c
index 996297ce0e..ae317177af 100644
--- a/libavformat/wtvdec.c
+++ b/libavformat/wtvdec.c
@@ -863,7 +863,8 @@ static int parse_chunks(AVFormatContext *s, int mode, int64_t seekts, int *len_p
                 }
 
                 buf_size = FFMIN(len - consumed, sizeof(buf));
-                avio_read(pb, buf, buf_size);
+                if (avio_read(pb, buf, buf_size) != buf_size)
+                    return AVERROR_INVALIDDATA;
                 consumed += buf_size;
                 ff_parse_mpeg2_descriptor(s, st, 0, &pbuf, buf + buf_size, NULL, 0, 0, NULL);
             }