avcodec/vb: Check input packet size to be large enough to contain flags

Fixes: Timeout (->9sec)
Fixes: 16292/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VB_fuzzer-5747063496638464
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavcodec/vb.c b/libavcodec/vb.c
index c6dd6fb4561e11a2004fb4707806b11355881e77..d9c6b93a7376fa5e5467703e069bfab56e8ff733 100644 (file)
--- a/libavcodec/vb.c
+++ b/libavcodec/vb.c
@@ -199,6 +199,9 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
     uint32_t size;
     int offset = 0;
 
+    if (avpkt->size < 2)
+        return AVERROR_INVALIDDATA;
+
     bytestream2_init(&c->stream, avpkt->data, avpkt->size);
 
     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)