[FFmpeg-cvslog] avcodec/wmalosslessdec: Check remaining space before padding and channel residue

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Sep 13 21:12:17 2020 +0200| [c467adf3bf9bb4b7fd28956ec698d884e63f145d] | committer: Michael Niedermayer

avcodec/wmalosslessdec: Check remaining space before padding and channel residue

Fixes: Timeout (1101sec -> 0.4sec)
Fixes: 24491/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5725337036783616

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=c467adf3bf9bb4b7fd28956ec698d884e63f145d
---

 libavcodec/wmalosslessdec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index 725e811070..b8d0f6220d 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -932,6 +932,8 @@ static int decode_subframe(WmallDecodeCtx *s)
             s->do_lpc = 0;
     }
 
+    if (get_bits_left(&s->gb) < 1)
+        return AVERROR_INVALIDDATA;
 
     if (get_bits1(&s->gb))
         padding_zeroes = get_bits(&s->gb, 5);