avcodec/ffv1dec: Check chroma shift parameters

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit d43cd6b0)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/ffv1dec.c

@@ -536,6 +536,12 @@ static int read_extra_header(FFV1Context *f)
     f->num_h_slices               = 1 + get_symbol(c, state, 0);
     f->num_v_slices               = 1 + get_symbol(c, state, 0);
 
+    if (f->chroma_h_shift > 4U || f->chroma_v_shift > 4U) {
+        av_log(f->avctx, AV_LOG_ERROR, "chroma shift parameters %d %d are invalid\n",
+               f->chroma_h_shift, f->chroma_v_shift);
+        return AVERROR_INVALIDDATA;
+    }
+
     if (f->num_h_slices > (unsigned)f->width  || !f->num_h_slices ||
         f->num_v_slices > (unsigned)f->height || !f->num_v_slices
        ) {
@@ -641,6 +647,12 @@ static int read_header(FFV1Context *f)
             }
         }
 
+        if (chroma_h_shift > 4U || chroma_v_shift > 4U) {
+            av_log(f->avctx, AV_LOG_ERROR, "chroma shift parameters %d %d are invalid\n",
+                   chroma_h_shift, chroma_v_shift);
+            return AVERROR_INVALIDDATA;
+        }
+
         f->colorspace                 = colorspace;
         f->avctx->bits_per_raw_sample = bits_per_raw_sample;
         f->chroma_planes              = chroma_planes;