paycheck.py revision be8ceab2a94fc68a4e4521e1f3e818a671c44414 
1#!/usr/bin/python
2#
3# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7"""Command-line tool for checking and applying Chrome OS update payloads."""
8
9import optparse
10import os
11import sys
12
13# pylint: disable=F0401
14lib_dir = os.path.join(os.path.dirname(__file__), 'lib')
15if os.path.exists(lib_dir) and os.path.isdir(lib_dir):
16  sys.path.insert(1, lib_dir)
17import update_payload
18
19
20_TYPE_FULL = 'full'
21_TYPE_DELTA = 'delta'
22
23
24def ParseArguments(argv):
25  """Parse and validate command-line arguments.
26
27  Args:
28    argv: command-line arguments to parse (excluding the program name)
29  Returns:
30    A tuple (opts, payload, extra_args), where `opts' are the options
31    returned by the parser, `payload' is the name of the payload file
32    (mandatory argument) and `extra_args' are any additional command-line
33    arguments.
34
35  """
36  parser = optparse.OptionParser(
37      usage=('Usage: %prog [OPTION...] PAYLOAD [DST_KERN DST_ROOT '
38             '[SRC_KERN SRC_ROOT]]'),
39      description=('Applies a Chrome OS update PAYLOAD to SRC_KERN and '
40                   'SRC_ROOT emitting DST_KERN and DST_ROOT, respectively. '
41                   'SRC_KERN and SRC_ROOT are only needed for delta payloads. '
42                   'When no partitions are provided, verifies the payload '
43                   'integrity.'),
44      epilog=('Note: a payload may verify correctly but fail to apply, and '
45              'vice versa; this is by design and can be thought of as static '
46              'vs dynamic correctness. A payload that both verifies and '
47              'applies correctly should be safe for use by the Chrome OS '
48              'Update Engine. Use --check to verify a payload prior to '
49              'applying it.'))
50
51  default_key = os.path.join(lib_dir,
52                             'update_payload/update-payload-key.pub.pem')
53
54  check_opts = optparse.OptionGroup(parser, 'Payload integrity checking')
55  check_opts.add_option('-c', '--check', action='store_true', default=False,
56                        help=('force payload integrity check (e.g. before '
57                              'applying)'))
58  check_opts.add_option('-r', '--report', metavar='FILE',
59                        help="dump payload report (`-' for stdout)")
60  check_opts.add_option('-t', '--type', metavar='TYPE', dest='assert_type',
61                        help=("assert that payload is either `%s' or `%s'" %
62                              (_TYPE_FULL, _TYPE_DELTA)))
63  check_opts.add_option('-z', '--block-size', metavar='NUM', default=0,
64                        type='int',
65                        help='assert a non-default (4096) payload block size')
66  check_opts.add_option('-u', '--allow-unhashed', action='store_true',
67                        default=False, help='allow unhashed operations')
68  check_opts.add_option('-d', '--disabled_tests', metavar='TESTLIST',
69                        default=(),
70                        help=('comma-separated list of tests to disable; '
71                              'available values: ' +
72                              ', '.join(update_payload.CHECKS_TO_DISABLE)))
73  check_opts.add_option('-k', '--key', metavar='FILE',
74                        help='Override standard key used for signature '
75                             'validation',
76                        default=default_key)
77  check_opts.add_option('-m', '--meta-sig', metavar='FILE',
78                        help='verify metadata against its signature')
79  parser.add_option_group(check_opts)
80
81  trace_opts = optparse.OptionGroup(parser, 'Block tracing')
82  trace_opts.add_option('-b', '--root-block', metavar='BLOCK', type='int',
83                        help='trace the origin for a rootfs block')
84  trace_opts.add_option('-B', '--kern-block', metavar='BLOCK', type='int',
85                        help='trace the origin for a kernel block')
86  trace_opts.add_option('-s', '--skip', metavar='NUM', default='0', type='int',
87                        help='skip first NUM occurrences of traced block')
88  parser.add_option_group(trace_opts)
89
90  # Parse command-line arguments.
91  opts, args = parser.parse_args(argv)
92
93  # Validate a value given to --type, if any.
94  if opts.assert_type not in (None, _TYPE_FULL, _TYPE_DELTA):
95    parser.error('invalid argument to --type: %s' % opts.assert_type)
96
97  # Convert and validate --disabled_tests value list, if provided.
98  if opts.disabled_tests:
99    opts.disabled_tests = opts.disabled_tests.split(',')
100    for test in opts.disabled_tests:
101      if test not in update_payload.CHECKS_TO_DISABLE:
102        parser.error('invalid argument to --disabled_tests: %s' % test)
103
104  # Ensure consistent use of block tracing options.
105  do_block_trace = opts.root_block or opts.kern_block
106  if opts.skip and not do_block_trace:
107    parser.error('--skip must be used with either --root-block or --kern-block')
108
109  # There are several options that imply --check.
110  opts.check = (opts.check or opts.report or opts.assert_type or
111                opts.block_size or opts.allow_unhashed or opts.key or
112                opts.meta_sig)
113
114  # Check number of arguments, enforce payload type accordingly.
115  if len(args) == 3:
116    if opts.assert_type == _TYPE_DELTA:
117      parser.error('%s payload requires source partition arguments' %
118                   _TYPE_DELTA)
119    opts.assert_type = _TYPE_FULL
120  elif len(args) == 5:
121    if opts.assert_type == _TYPE_FULL:
122      parser.error('%s payload does not accept source partition arguments' %
123                   _TYPE_FULL)
124    opts.assert_type = _TYPE_DELTA
125  elif len(args) == 1:
126    # Not applying payload; if block tracing not requested either, do an
127    # integrity check.
128    if not do_block_trace:
129      opts.check = True
130  else:
131    parser.error('unexpected number of arguments')
132
133  # By default, look for a metadata-signature file with a name based on the name
134  # of the payload we are checking.
135  if not opts.meta_sig:
136    print "Looking for default signature."
137    default_meta_sig = args[0] + '.metadata-signature'
138    if os.path.isfile(default_meta_sig):
139      opts.meta_sig = default_meta_sig
140      print "Using default signature %s." % opts.meta_sig
141
142  return opts, args[0], args[1:]
143
144
145def main(argv):
146  # Parse and validate arguments.
147  options, payload_file_name, extra_args = ParseArguments(argv[1:])
148
149  with open(payload_file_name) as payload_file:
150    payload = update_payload.Payload(payload_file)
151    try:
152      # Initialize payload.
153      payload.Init()
154
155      # Perform payload integrity checks.
156      if options.check:
157        report_file = None
158        do_close_report_file = False
159        try:
160          if options.report:
161            if options.report == '-':
162              report_file = sys.stdout
163            else:
164              report_file = open(options.report, 'w')
165              do_close_report_file = True
166
167          payload.Check(
168              pubkey_file_name=options.key,
169              metadata_sig_file=open(options.meta_sig)
170              if options.meta_sig else None,
171              report_out_file=report_file,
172              assert_type=options.assert_type,
173              block_size=int(options.block_size),
174              allow_unhashed=options.allow_unhashed,
175              disabled_tests=options.disabled_tests)
176        finally:
177          if do_close_report_file:
178            report_file.close()
179
180      # Trace blocks.
181      if options.root_block is not None:
182        payload.TraceBlock(options.root_block, options.skip, sys.stdout, False)
183      if options.kern_block is not None:
184        payload.TraceBlock(options.kern_block, options.skip, sys.stdout, True)
185
186      # Apply payload.
187      if extra_args:
188        if options.assert_type == _TYPE_FULL:
189          payload.Apply(extra_args[0], extra_args[1])
190        elif options.assert_type == _TYPE_DELTA:
191          payload.Apply(extra_args[0], extra_args[1],
192                        src_kernel_part=extra_args[2],
193                        src_rootfs_part=extra_args[3])
194        else:
195          assert False, 'cannot get here'
196
197    except update_payload.PayloadError, e:
198      sys.stderr.write('Error: %s\n' % e)
199      return 1
200
201  return 0
202
203
204if __name__ == '__main__':
205  sys.exit(main(sys.argv))
206