mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-09 22:33:28 +09:00
![Philippe Reynes](/assets/img/avatar_default.png)
The pytest vboot does all his tests on fit without padding. We add the same tests on fit with padding. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
321 lines
12 KiB
Python
321 lines
12 KiB
Python
# SPDX-License-Identifier: GPL-2.0+
|
|
# Copyright (c) 2016, Google Inc.
|
|
#
|
|
# U-Boot Verified Boot Test
|
|
|
|
"""
|
|
This tests verified boot in the following ways:
|
|
|
|
For image verification:
|
|
- Create FIT (unsigned) with mkimage
|
|
- Check that verification shows that no keys are verified
|
|
- Sign image
|
|
- Check that verification shows that a key is now verified
|
|
|
|
For configuration verification:
|
|
- Corrupt signature and check for failure
|
|
- Create FIT (with unsigned configuration) with mkimage
|
|
- Check that image verification works
|
|
- Sign the FIT and mark the key as 'required' for verification
|
|
- Check that image verification works
|
|
- Corrupt the signature
|
|
- Check that image verification no-longer works
|
|
|
|
Tests run with both SHA1 and SHA256 hashing.
|
|
"""
|
|
|
|
import struct
|
|
import pytest
|
|
import u_boot_utils as util
|
|
import vboot_forge
|
|
|
|
TESTDATA = [
|
|
['sha1', '', None, False],
|
|
['sha1', '', '-E -p 0x10000', False],
|
|
['sha1', '-pss', None, False],
|
|
['sha1', '-pss', '-E -p 0x10000', False],
|
|
['sha256', '', None, False],
|
|
['sha256', '', '-E -p 0x10000', False],
|
|
['sha256', '-pss', None, False],
|
|
['sha256', '-pss', '-E -p 0x10000', False],
|
|
['sha256', '-pss', None, True],
|
|
['sha256', '-pss', '-E -p 0x10000', True],
|
|
]
|
|
|
|
@pytest.mark.boardspec('sandbox')
|
|
@pytest.mark.buildconfigspec('fit_signature')
|
|
@pytest.mark.requiredtool('dtc')
|
|
@pytest.mark.requiredtool('fdtget')
|
|
@pytest.mark.requiredtool('fdtput')
|
|
@pytest.mark.requiredtool('openssl')
|
|
@pytest.mark.parametrize("sha_algo,padding,sign_options,required", TESTDATA)
|
|
def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
|
|
"""Test verified boot signing with mkimage and verification with 'bootm'.
|
|
|
|
This works using sandbox only as it needs to update the device tree used
|
|
by U-Boot to hold public keys from the signing process.
|
|
|
|
The SHA1 and SHA256 tests are combined into a single test since the
|
|
key-generation process is quite slow and we want to avoid doing it twice.
|
|
"""
|
|
def dtc(dts):
|
|
"""Run the device tree compiler to compile a .dts file
|
|
|
|
The output file will be the same as the input file but with a .dtb
|
|
extension.
|
|
|
|
Args:
|
|
dts: Device tree file to compile.
|
|
"""
|
|
dtb = dts.replace('.dts', '.dtb')
|
|
util.run_and_log(cons, 'dtc %s %s%s -O dtb '
|
|
'-o %s%s' % (dtc_args, datadir, dts, tmpdir, dtb))
|
|
|
|
def run_bootm(sha_algo, test_type, expect_string, boots):
|
|
"""Run a 'bootm' command U-Boot.
|
|
|
|
This always starts a fresh U-Boot instance since the device tree may
|
|
contain a new public key.
|
|
|
|
Args:
|
|
test_type: A string identifying the test type.
|
|
expect_string: A string which is expected in the output.
|
|
sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
|
|
use.
|
|
boots: A boolean that is True if Linux should boot and False if
|
|
we are expected to not boot
|
|
"""
|
|
cons.restart_uboot()
|
|
with cons.log.section('Verified boot %s %s' % (sha_algo, test_type)):
|
|
output = cons.run_command_list(
|
|
['host load hostfs - 100 %stest.fit' % tmpdir,
|
|
'fdt addr 100',
|
|
'bootm 100'])
|
|
assert expect_string in ''.join(output)
|
|
if boots:
|
|
assert 'sandbox: continuing, as we cannot run' in ''.join(output)
|
|
else:
|
|
assert('sandbox: continuing, as we cannot run'
|
|
not in ''.join(output))
|
|
|
|
def make_fit(its):
|
|
"""Make a new FIT from the .its source file.
|
|
|
|
This runs 'mkimage -f' to create a new FIT.
|
|
|
|
Args:
|
|
its: Filename containing .its source.
|
|
"""
|
|
util.run_and_log(cons, [mkimage, '-D', dtc_args, '-f',
|
|
'%s%s' % (datadir, its), fit])
|
|
|
|
def sign_fit(sha_algo, options):
|
|
"""Sign the FIT
|
|
|
|
Signs the FIT and writes the signature into it. It also writes the
|
|
public key into the dtb.
|
|
|
|
Args:
|
|
sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
|
|
use.
|
|
options: Options to provide to mkimage.
|
|
"""
|
|
args = [mkimage, '-F', '-k', tmpdir, '-K', dtb, '-r', fit]
|
|
if options:
|
|
args += options.split(' ')
|
|
cons.log.action('%s: Sign images' % sha_algo)
|
|
util.run_and_log(cons, args)
|
|
|
|
def replace_fit_totalsize(size):
|
|
"""Replace FIT header's totalsize with something greater.
|
|
|
|
The totalsize must be less than or equal to FIT_SIGNATURE_MAX_SIZE.
|
|
If the size is greater, the signature verification should return false.
|
|
|
|
Args:
|
|
size: The new totalsize of the header
|
|
|
|
Returns:
|
|
prev_size: The previous totalsize read from the header
|
|
"""
|
|
total_size = 0
|
|
with open(fit, 'r+b') as handle:
|
|
handle.seek(4)
|
|
total_size = handle.read(4)
|
|
handle.seek(4)
|
|
handle.write(struct.pack(">I", size))
|
|
return struct.unpack(">I", total_size)[0]
|
|
|
|
def create_rsa_pair(name):
|
|
"""Generate a new RSA key paid and certificate
|
|
|
|
Args:
|
|
name: Name of of the key (e.g. 'dev')
|
|
"""
|
|
public_exponent = 65537
|
|
util.run_and_log(cons, 'openssl genpkey -algorithm RSA -out %s%s.key '
|
|
'-pkeyopt rsa_keygen_bits:2048 '
|
|
'-pkeyopt rsa_keygen_pubexp:%d' %
|
|
(tmpdir, name, public_exponent))
|
|
|
|
# Create a certificate containing the public key
|
|
util.run_and_log(cons, 'openssl req -batch -new -x509 -key %s%s.key '
|
|
'-out %s%s.crt' % (tmpdir, name, tmpdir, name))
|
|
|
|
def test_with_algo(sha_algo, padding, sign_options):
|
|
"""Test verified boot with the given hash algorithm.
|
|
|
|
This is the main part of the test code. The same procedure is followed
|
|
for both hashing algorithms.
|
|
|
|
Args:
|
|
sha_algo: Either 'sha1' or 'sha256', to select the algorithm to
|
|
use.
|
|
padding: Either '' or '-pss', to select the padding to use for the
|
|
rsa signature algorithm.
|
|
sign_options: Options to mkimage when signing a fit image.
|
|
"""
|
|
# Compile our device tree files for kernel and U-Boot. These are
|
|
# regenerated here since mkimage will modify them (by adding a
|
|
# public key) below.
|
|
dtc('sandbox-kernel.dts')
|
|
dtc('sandbox-u-boot.dts')
|
|
|
|
# Build the FIT, but don't sign anything yet
|
|
cons.log.action('%s: Test FIT with signed images' % sha_algo)
|
|
make_fit('sign-images-%s%s.its' % (sha_algo, padding))
|
|
run_bootm(sha_algo, 'unsigned images', 'dev-', True)
|
|
|
|
# Sign images with our dev keys
|
|
sign_fit(sha_algo, sign_options)
|
|
run_bootm(sha_algo, 'signed images', 'dev+', True)
|
|
|
|
# Create a fresh .dtb without the public keys
|
|
dtc('sandbox-u-boot.dts')
|
|
|
|
cons.log.action('%s: Test FIT with signed configuration' % sha_algo)
|
|
make_fit('sign-configs-%s%s.its' % (sha_algo, padding))
|
|
run_bootm(sha_algo, 'unsigned config', '%s+ OK' % sha_algo, True)
|
|
|
|
# Sign images with our dev keys
|
|
sign_fit(sha_algo, sign_options)
|
|
run_bootm(sha_algo, 'signed config', 'dev+', True)
|
|
|
|
cons.log.action('%s: Check signed config on the host' % sha_algo)
|
|
|
|
util.run_and_log(cons, [fit_check_sign, '-f', fit, '-k', dtb])
|
|
|
|
# Make sure that U-Boot checks that the config is in the list of hashed
|
|
# nodes. If it isn't, a security bypass is possible.
|
|
with open(fit, 'rb') as fd:
|
|
root, strblock = vboot_forge.read_fdt(fd)
|
|
root, strblock = vboot_forge.manipulate(root, strblock)
|
|
with open(fit, 'w+b') as fd:
|
|
vboot_forge.write_fdt(root, strblock, fd)
|
|
util.run_and_log_expect_exception(
|
|
cons, [fit_check_sign, '-f', fit, '-k', dtb],
|
|
1, 'Failed to verify required signature')
|
|
|
|
run_bootm(sha_algo, 'forged config', 'Bad Data Hash', False)
|
|
|
|
# Create a new properly signed fit and replace header bytes
|
|
make_fit('sign-configs-%s%s.its' % (sha_algo, padding))
|
|
sign_fit(sha_algo, sign_options)
|
|
bcfg = u_boot_console.config.buildconfig
|
|
max_size = int(bcfg.get('config_fit_signature_max_size', 0x10000000), 0)
|
|
existing_size = replace_fit_totalsize(max_size + 1)
|
|
run_bootm(sha_algo, 'Signed config with bad hash', 'Bad Data Hash',
|
|
False)
|
|
cons.log.action('%s: Check overflowed FIT header totalsize' % sha_algo)
|
|
|
|
# Replace with existing header bytes
|
|
replace_fit_totalsize(existing_size)
|
|
run_bootm(sha_algo, 'signed config', 'dev+', True)
|
|
cons.log.action('%s: Check default FIT header totalsize' % sha_algo)
|
|
|
|
# Increment the first byte of the signature, which should cause failure
|
|
sig = util.run_and_log(cons, 'fdtget -t bx %s %s value' %
|
|
(fit, sig_node))
|
|
byte_list = sig.split()
|
|
byte = int(byte_list[0], 16)
|
|
byte_list[0] = '%x' % (byte + 1)
|
|
sig = ' '.join(byte_list)
|
|
util.run_and_log(cons, 'fdtput -t bx %s %s value %s' %
|
|
(fit, sig_node, sig))
|
|
|
|
run_bootm(sha_algo, 'Signed config with bad hash', 'Bad Data Hash',
|
|
False)
|
|
|
|
cons.log.action('%s: Check bad config on the host' % sha_algo)
|
|
util.run_and_log_expect_exception(
|
|
cons, [fit_check_sign, '-f', fit, '-k', dtb],
|
|
1, 'Failed to verify required signature')
|
|
|
|
def test_required_key(sha_algo, padding, sign_options):
|
|
"""Test verified boot with the given hash algorithm.
|
|
|
|
This function tests if U-Boot rejects an image when a required key isn't
|
|
used to sign a FIT.
|
|
|
|
Args:
|
|
sha_algo: Either 'sha1' or 'sha256', to select the algorithm to use
|
|
padding: Either '' or '-pss', to select the padding to use for the
|
|
rsa signature algorithm.
|
|
sign_options: Options to mkimage when signing a fit image.
|
|
"""
|
|
# Compile our device tree files for kernel and U-Boot. These are
|
|
# regenerated here since mkimage will modify them (by adding a
|
|
# public key) below.
|
|
dtc('sandbox-kernel.dts')
|
|
dtc('sandbox-u-boot.dts')
|
|
|
|
cons.log.action('%s: Test FIT with configs images' % sha_algo)
|
|
|
|
# Build the FIT with prod key (keys required) and sign it. This puts the
|
|
# signature into sandbox-u-boot.dtb, marked 'required'
|
|
make_fit('sign-configs-%s%s-prod.its' % (sha_algo, padding))
|
|
sign_fit(sha_algo, sign_options)
|
|
|
|
# Build the FIT with dev key (keys NOT required). This adds the
|
|
# signature into sandbox-u-boot.dtb, NOT marked 'required'.
|
|
make_fit('sign-configs-%s%s.its' % (sha_algo, padding))
|
|
sign_fit(sha_algo, sign_options)
|
|
|
|
# So now sandbox-u-boot.dtb two signatures, for the prod and dev keys.
|
|
# Only the prod key is set as 'required'. But FIT we just built has
|
|
# a dev signature only (sign_fit() overwrites the FIT).
|
|
# Try to boot the FIT with dev key. This FIT should not be accepted by
|
|
# U-Boot because the prod key is required.
|
|
run_bootm(sha_algo, 'required key', '', False)
|
|
|
|
cons = u_boot_console
|
|
tmpdir = cons.config.result_dir + '/'
|
|
datadir = cons.config.source_dir + '/test/py/tests/vboot/'
|
|
fit = '%stest.fit' % tmpdir
|
|
mkimage = cons.config.build_dir + '/tools/mkimage'
|
|
fit_check_sign = cons.config.build_dir + '/tools/fit_check_sign'
|
|
dtc_args = '-I dts -O dtb -i %s' % tmpdir
|
|
dtb = '%ssandbox-u-boot.dtb' % tmpdir
|
|
sig_node = '/configurations/conf-1/signature'
|
|
|
|
create_rsa_pair('dev')
|
|
create_rsa_pair('prod')
|
|
|
|
# Create a number kernel image with zeroes
|
|
with open('%stest-kernel.bin' % tmpdir, 'w') as fd:
|
|
fd.write(500 * chr(0))
|
|
|
|
try:
|
|
# We need to use our own device tree file. Remember to restore it
|
|
# afterwards.
|
|
old_dtb = cons.config.dtb
|
|
cons.config.dtb = dtb
|
|
if required:
|
|
test_required_key(sha_algo, padding, sign_options)
|
|
else:
|
|
test_with_algo(sha_algo, padding, sign_options)
|
|
finally:
|
|
# Go back to the original U-Boot with the correct dtb.
|
|
cons.config.dtb = old_dtb
|
|
cons.restart_uboot()
|