ra288: Check block align.

Fixes OOM
Fixes Ticket1893

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/ra288.c

@@ -67,6 +67,11 @@ static av_cold int ra288_decode_init(AVCodecContext *avctx)
     avctx->channel_layout = AV_CH_LAYOUT_MONO;
     avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;
 
+    if (avctx->block_align <= 0) {
+        av_log_ask_for_sample(avctx, "unsupported block align\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
     avpriv_float_dsp_init(&ractx->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
 
     avcodec_get_frame_defaults(&ractx->frame);