Merge commit '18a245a2'

* commit '18a245a2':
  jpeg2000dec: Add more checks when parsing headers

The check cannot be true in FFmpeg, but does no harm.
I will move it in a subsequent commit so it can detect missing SIZ
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/jpeg2000dec.c

@@ -1394,6 +1394,10 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
                 av_log(s->avctx, AV_LOG_ERROR, "Missing SOT\n");
                 return AVERROR_INVALIDDATA;
             }
+            if (!s->tile) {
+                av_log(s->avctx, AV_LOG_ERROR, "Missing SIZ\n");
+                return AVERROR_INVALIDDATA;
+            }
 
             tile = s->tile + s->curtileno;
             tp = tile->tile_part + tile->tp_idx;