[FFmpeg-devel] [PATCH 2/3] avcodec/vp3: Check version in all cases when VP4 code is not built

[Michael Niedermayer]

Fixes: out of array read
Fixes: 40284/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VP3_fuzzer-4599568176644096

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/vp3.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
index 16726080b35..5b9ba60f499 100644
--- a/libavcodec/vp3.c
+++ b/libavcodec/vp3.c
@@ -2685,7 +2685,14 @@ static int vp3_decode_frame(AVCodecContext *avctx,
             skip_bits(&gb, 4); /* width code */
             skip_bits(&gb, 4); /* height code */
             if (s->version) {
-                s->version = get_bits(&gb, 5);
+                int version = get_bits(&gb, 5);
+#if !CONFIG_VP4_DECODER
+                if (version >= 2) {
+                    av_log(avctx, AV_LOG_ERROR, "This build does not support decoding VP4.\n");
+                    return AVERROR_DECODER_NOT_FOUND;
+                }
+#endif
+                s->version = version;
                 if (avctx->frame_number == 0)
                     av_log(s->avctx, AV_LOG_DEBUG,
                            "VP version: %d\n", s->version);
-- 
2.17.1