[wasm] Add HB_ARRAY_APP2NATIVE

src/hb-wasm-api-buffer.hh

@@ -113,10 +113,8 @@ HB_WASM_API (bool_t, buffer_copy_contents) (HB_WASM_EXEC_ENV
 
   if (length <= contents->length)
   {
-    unsigned bytes = length * sizeof (hb_glyph_info_t);
-
-    glyph_info_t *info = (glyph_info_t *) (validate_app_addr (contents->info, bytes) ? addr_app_to_native (contents->info) : nullptr);
-    glyph_position_t *pos = (glyph_position_t *) (validate_app_addr (contents->pos, bytes) ? addr_app_to_native (contents->pos) : nullptr);
+    glyph_info_t *info = HB_ARRAY_APP2NATIVE (glyph_info_t, contents->info, length);
+    glyph_position_t *pos = HB_ARRAY_APP2NATIVE (glyph_position_t, contents->pos, length);
 
     if (unlikely (!info || !pos))
     {
@@ -124,6 +122,7 @@ HB_WASM_API (bool_t, buffer_copy_contents) (HB_WASM_EXEC_ENV
       return false;
     }
 
+    unsigned bytes = length * sizeof (hb_glyph_info_t);
     memcpy (info, buffer->info, bytes);
     memcpy (pos, buffer->pos, bytes);
 

src/hb-wasm-api-face.hh

@@ -48,7 +48,7 @@ HB_WASM_API (bool_t, face_copy_table) (HB_WASM_EXEC_ENV
 
   if (length <= blob->length)
   {
-    char *data = (char *) (validate_app_addr (blob->data, length) ? addr_app_to_native (blob->data) : nullptr);
+    char *data = HB_ARRAY_APP2NATIVE (char, blob->data, length);
 
     if (unlikely (!data))
     {

src/hb-wasm-api-font.hh

@@ -140,8 +140,8 @@ HB_WASM_API (bool_t, font_copy_glyph_outline) (HB_WASM_EXEC_ENV
   if (hb_outline.points.length <= outline->n_points &&
       hb_outline.contours.length <= outline->n_contours)
   {
-    glyph_outline_point_t *points = (glyph_outline_point_t *) (validate_app_addr (outline->points, hb_outline.points.get_size ()) ? addr_app_to_native (outline->points) : nullptr);
-    uint32_t *contours = (uint32_t *) (validate_app_addr (outline->contours, hb_outline.contours.get_size ()) ? addr_app_to_native (outline->contours) : nullptr);
+    glyph_outline_point_t *points = HB_ARRAY_APP2NATIVE (glyph_outline_point_t, outline->points, hb_outline.points.length);
+    uint32_t *contours = HB_ARRAY_APP2NATIVE (uint32_t, outline->contours, hb_outline.contours.length);
 
     if (unlikely (!points || !contours))
     {

src/hb-wasm-api.hh

@@ -108,5 +108,10 @@ HB_INTERNAL extern hb_user_data_key_t _hb_wasm_ref_type_key;
       name = (type *) wasm_runtime_addr_app_to_native (module_inst, name##ptr); \
   } HB_STMT_END
 
+#define HB_ARRAY_APP2NATIVE(type, name, length) \
+    ((type *) (!hb_unsigned_mul_overflows (length, sizeof (type)) && \
+	       validate_app_addr (name, (length) * sizeof (type)) ? \
+	       addr_app_to_native (name) : nullptr))
+
 
 #endif /* HB_WASM_API_HH */