skip invalid blocks more efficiently

volatility3/framework/layers/intel.py

@@ -269,9 +269,12 @@ class Intel(linear.LinearlyMappedLayer):
     @functools.lru_cache(maxsize=1025)
     def _get_valid_table(self, base_address: int) -> Optional[bytes]:
         """Extracts the table, validates it and returns it if it's valid."""
-        table = self._context.layers.read(
-            self._base_layer, base_address, self.page_size
-        )
+        try:
+            table = self._context.layers.read(
+                self._base_layer, base_address, self.page_size
+            )
+        except exceptions.InvalidAddressException:
+            return None
 
         # If the table is entirely duplicates, then mark the whole table as bad
         if table == table[: self._entry_size] * self._entry_number:
@@ -375,12 +378,19 @@ class Intel(linear.LinearlyMappedLayer):
         while length > 0:
             try:
                 chunk_offset, page_size, layer_name = self._translate(offset)
-                chunk_size = min(page_size - (chunk_offset % page_size), length)
+                # Page align the chunk size value
+                chunk_size = min(page_size - (offset % page_size), length)
                 if not self._context.layers[layer_name].is_valid(
                     chunk_offset, chunk_size
                 ):
-                    raise exceptions.InvalidAddressException(
-                        layer_name=layer_name, invalid_address=chunk_offset
+                    # Virtual -> physical is contiguous in the chunk_size range.
+                    # If we fail, we can jump directly to the end as we know all bytes in between
+                    # aren't mapped (virtually and) physically anyway.
+                    raise exceptions.PagedInvalidAddressException(
+                        layer_name=layer_name,
+                        invalid_address=chunk_offset,
+                        entry=0,
+                        invalid_bits=int(math.log2(chunk_size)),
                     )
             except (
                 exceptions.PagedInvalidAddressException,