Change ROM hash calculation to trust FMAP

client/site_tests/hardware_Components/hardware_Components.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import glob, hashlib, logging, os, pprint, re, sys
 from autotest_lib.client.bin import factory
 from autotest_lib.client.bin import test, utils
 from autotest_lib.client.common_lib import error
 from autotest_lib.client.common_lib import flashrom_util
 from autotest_lib.client.common_lib import gbb_util
@@ skipping 234 matching lines @@
         Returns a hash of Read Only firmware parts,
         to confirm we have proper keys / boot code / recovery image installed.
         """
         # hash_ro_list: RO section to be hashed
         hash_ro_list = ['FV_BSTUB', 'FV_GBB', 'FVDEV']
         flashrom = flashrom_util.flashrom_util()
         if not flashrom.select_bios_flashrom():
             raise error.TestError('Cannot select BIOS flashrom')
         base_img = flashrom.read_whole()
         flashrom_size = len(base_img)
-        # XXX we can NOT trust base image here for layout, otherwise firmware
-        # can provide fake (non-used) GBB/BSTUB in garbage area.
-        layout = flashrom.detect_chromeos_bios_layout(flashrom_size, None)
+        # XXX Allowing the FMAP to override our default layout may be an exploit
+        # here, because vendor can provide fake (non-used) GBB/BSTUB in unused
+        # area.  However since the flash memory layout may change, we need to
+        # trust FMAP here.
+        layout = flashrom.detect_chromeos_bios_layout(flashrom_size, base_img)
         if not layout:
             raise error.TestError('Cannot detect ChromeOS flashrom layout')
         hash_src = ''
         for section in hash_ro_list:
             src = flashrom.get_section(base_img, layout, section)
             if not src:
                 raise error.TestError('Cannot get section [%s] from flashrom' %
                                       section)
             hash_src = hash_src + src
         if not hash_src:
@@ skipping 105 matching lines @@
                 cids_need_to_be_record = ['part_id_hwqual']
                 for cid in cids_need_to_be_record:
                     factory.log_shared_data(cid, self._approved[cid][0])
                 return
 
         if only_cardreader_failed:
             all_failures = ('You may forget to insert an SD card.\n' +
                             all_failures)
 
         raise error.TestFail(all_failures)