avcodec/utvideodec: Check subsample factors

Fixes: Out of array read
Fixes: heap_poc
Found-by: GwanYeong Kim <gy741.kim@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 7414d0bd)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/utvideodec.c

@@ -28,6 +28,7 @@
 #include <stdlib.h>
 
 #include "libavutil/intreadwrite.h"
+#include "libavutil/pixdesc.h"
 #include "avcodec.h"
 #include "bswapdsp.h"
 #include "bytestream.h"
@@ -474,6 +475,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     UtvideoContext * const c = avctx->priv_data;
+    int h_shift, v_shift;
 
     c->avctx = avctx;
 
@@ -538,6 +540,13 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return AVERROR_INVALIDDATA;
     }
 
+    av_pix_fmt_get_chroma_sub_sample(avctx->pix_fmt, &h_shift, &v_shift);
+    if ((avctx->width  & ((1<<h_shift)-1)) ||
+        (avctx->height & ((1<<v_shift)-1))) {
+        avpriv_request_sample(avctx, "Odd dimensions");
+        return AVERROR_PATCHWELCOME;
+    }
+
     return 0;
 }