avcodec/huffyuvdec: Check that slice height is non negative.

Fixes: out of array access
Fixes: 12381/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HYMT_fuzzer-5705474280783872
Fixes: 12384/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HYMT_fuzzer-5725303345774592
Fixes: 12389/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HYMT_fuzzer-5704033050820608
Fixes: 12391/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HYMT_fuzzer-5707284146028544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/huffyuvdec.c

@@ -1254,7 +1254,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
         slices_info_offset = AV_RL32(avpkt->data + buf_size - 4);
         slice_height = AV_RL32(avpkt->data + buf_size - 8);
         nb_slices = AV_RL32(avpkt->data + buf_size - 12);
-        if (nb_slices * 8LL + slices_info_offset > buf_size - 16)
+        if (nb_slices * 8LL + slices_info_offset > buf_size - 16 || slice_height <= 0)
             return AVERROR_INVALIDDATA;
     } else {
         slice_height = height;