cr50: add firmware upgrade test

This extends the test harness with a test verifying firmware upgrade.
The test in fact just determines the area available for upgrade, picks
the appropriate image and sends it to the device, 1K at a time.

The test does not verify that the device in fact switched to the new
image, the test succeeds if the device accepts all update messages.

BRANCH=none
BUG=chrome-os-partner:37774
TEST=verified that all tests still pass:
   $ ./test/tpm_test/tpmtest.py
   Starting MPSSE at 800 kHz
   Connected to device vid:did:rid of 1ae0:0028:00
   SUCCESS: AES:ECB common
   SUCCESS: AES:ECB128 1
   SUCCESS: AES:ECB192 1
   SUCCESS: AES:ECB256 1
   SUCCESS: AES:ECB256 2
   SUCCESS: AES:CTR128I 1
   SUCCESS: AES:CTR256I 1
   SUCCESS: EC-SIGN:NIST-P256:ECDSA
   New max timeout: 1 s
   SUCCESS: EC-KEYGEN:NIST-P256
   SUCCESS: EC-KEYDERIVE:NIST-P256
   SUCCESS: sha1:single:0
   SUCCESS: sha256:single:0
   SUCCESS: sha1:single:3
   SUCCESS: sha256:single:3
   SUCCESS: sha256:finish:1
   SUCCESS: sha1:finish:3
   SUCCESS: sha256:finish:2
   -New max timeout: 3 s
   SUCCESS: RSA-ENC:OAEP:SHA1:768
   SUCCESS: RSA-ENC:OAEP:SHA256:768
   SUCCESS: RSA-ENC:PKCS1-ES:NONE:768
   New max timeout: 49 s
   SUCCESS: RSA-ENC:PKCS1-ES:NONE:2048
   SUCCESS: RSA-SIGN:PKCS1-SSA:SHA1:768
   SUCCESS: RSA-SIGN:PKCS1-SSA:SHA256:768
   SUCCESS: Firmware upgrade

Change-Id: I49052feb8e97a3e281bb20b7fddc359a55e96ae3
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/327416
Reviewed-by: Nagendra Modadugu <ngm@google.com>

test/tpm_test/subcmd.py

@@ -10,7 +10,7 @@ AES = 0
 HASH = 1
 RSA = 2
 EC = 3
-
+FW_UPGRADE = 4
 
 # The same exception class used by all tpmtest modules.
 class TpmTestError(Exception):

test/tpm_test/tpmtest.py

@@ -24,7 +24,7 @@ import ftdi_spi_tpm
 import hash_test
 import rsa_test
 import subcmd
-
+import upgrade_test
 
 # Extension command for dcypto testing
 EXT_CMD = 0xbaccd00a
@@ -137,6 +137,7 @@ if __name__ == '__main__':
     ecc_test.ecc_test(t)
     hash_test.hash_test(t)
     rsa_test.rsa_test(t)
+    upgrade_test.upgrade(t)
   except subcmd.TpmTestError as e:
     exc_file, exc_line = traceback.extract_tb(sys.exc_traceback)[-1][:2]
     print('\nError in %s:%s: ' % (os.path.basename(exc_file), exc_line), e)

test/tpm_test/upgrade_test.py

@@ -0,0 +1,68 @@
+#!/usr/bin/python
+# Copyright 2016 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.
+
+from __future__ import print_function
+
+import hashlib
+import os
+import struct
+
+import subcmd
+import utils
+
+
+def upgrade(tpm):
+  """Exercise the upgrade command.
+
+  The target expect the upgrade extension command to have the following
+  structure:
+
+  cmd         1  value of FW_UPGRADE
+  digest      4  first 4 bytes of sha1 of the remainder of the message
+  block_base  4  address of the block to write
+  data      var
+
+  Args:
+    tpm: a properly initialized tpmtest.TPM object
+    Raises:
+      subcmd.TpmTestError: In case of various test problems
+  """
+  cmd  = struct.pack('>I', 0)  # address
+  cmd += struct.pack('>I', 0)  # data (a noop)
+  wrapped_response = tpm.command(tpm.wrap_ext_command(subcmd.FW_UPGRADE, cmd))
+  base_str = tpm.unwrap_ext_response(subcmd.FW_UPGRADE, wrapped_response)
+  if len(base_str) < 4:
+    raise subcmd.TpmTestError('Initialization error %d' %
+                              ord(base_str[0]))
+  base = struct.unpack('>I', base_str)[0]
+  if base == 0x84000:
+    fname = 'build/cr50/RW/ec.RW_B.flat'
+  elif base == 0x44000:
+    fname = 'build/cr50/RW/ec.RW.flat'
+  else:
+    raise subcmd.TpmTestError('Unknown base address 0x%x' % base)
+  fname = os.path.join(os.path.dirname(__file__), '../..', fname)
+  data = open(fname, 'r').read()
+  transferred = 0
+  block_size = 1024
+
+  while transferred < len(data):
+    tx_size = min(block_size, len(data) - transferred)
+    chunk = data[transferred:transferred+tx_size]
+    cmd  = struct.pack('>I', base)  # address
+    h = hashlib.sha1()
+    h.update(cmd)
+    h.update(chunk)
+    cmd = h.digest()[0:4] + cmd + chunk
+    resp = tpm.unwrap_ext_response(subcmd.FW_UPGRADE,
+                                   tpm.command(tpm.wrap_ext_command(
+                                     subcmd.FW_UPGRADE, cmd)))
+    code = ord(resp[0])
+    if code:
+      raise subcmd.TpmTestError('%x - resp %d' % (base, code))
+    base += tx_size
+    transferred += tx_size
+
+  print('%sSUCCESS: Firmware upgrade' % (utils.cursor_back()))