[truetype] Minor update to forthcoming OpenType 1.8.4 standard.

* src/truetype/ttgxvar.c (ft_var_load_item_variation_store): Limit
size of `regionCount`.

ChangeLog

@@ -1,3 +1,10 @@
+2020-10-28  Werner Lemberg  <wl@gnu.org>
+
+	[truetype] Minor update to forthcoming OpenType 1.8.4 standard.
+
+	* src/truetype/ttgxvar.c (ft_var_load_item_variation_store): Limit
+	size of `regionCount`.
+
 2020-10-26  Werner Lemberg  <wl@gnu.org>
 
 	* meson.build: Fix 'harfbuzz' and 'brotli' build options (#59347).

src/truetype/ttgxvar.c

@@ -493,6 +493,15 @@
       goto Exit;
     }
 
+    /* new constraint in OpenType 1.8.4 */
+    if ( itemStore->regionCount >= 32768U )
+    {
+      FT_TRACE2(( "ft_var_load_item_variation_store:"
+                  " too many variation region tables\n" ));
+      error = FT_THROW( Invalid_Table );
+      goto Exit;
+    }
+
     if ( FT_NEW_ARRAY( itemStore->varRegionList, itemStore->regionCount ) )
       goto Exit;