-# Copyright (c) 2016, Google Inc.
-#
# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2016, Google Inc.
#
# U-Boot Verified Boot Test
import pytest
import sys
+import struct
import u_boot_utils as util
+import vboot_forge
+
+TESTDATA = [
+ ['sha1', '', False],
+ ['sha1', '-pss', False],
+ ['sha256', '', False],
+ ['sha256', '-pss', False],
+ ['sha256', '-pss', True],
+]
@pytest.mark.boardspec('sandbox')
@pytest.mark.buildconfigspec('fit_signature')
-def test_vboot(u_boot_console):
+@pytest.mark.requiredtool('dtc')
+@pytest.mark.requiredtool('fdtget')
+@pytest.mark.requiredtool('fdtput')
+@pytest.mark.requiredtool('openssl')
+@pytest.mark.parametrize("sha_algo,padding,required", TESTDATA)
+def test_vboot(u_boot_console, sha_algo, padding, 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
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):
+ 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
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(
- ['sb load hostfs - 100 %stest.fit' % tmpdir,
+ ['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.
util.run_and_log(cons, [mkimage, '-F', '-k', tmpdir, '-K', dtb,
'-r', fit])
- def test_with_algo(sha_algo):
+ def sign_fit_norequire(sha_algo):
+ """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.
+ """
+ cons.log.action('%s: Sign images' % sha_algo)
+ util.run_and_log(cons, [mkimage, '-F', '-k', tmpdir, '-K', dtb,
+ fit])
+
+ 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 test_with_algo(sha_algo, padding):
"""Test verified boot with the given hash algorithm.
This is the main part of the test code. The same procedure is followed
# 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.its' % sha_algo)
- run_bootm(sha_algo, 'unsigned images', 'dev-')
+ 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)
- run_bootm(sha_algo, 'signed images', 'dev+')
+ 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.its' % sha_algo)
- run_bootm(sha_algo, 'unsigned config', '%s+ OK' % 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)
- run_bootm(sha_algo, 'signed config', 'dev+')
+ 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', tmpdir,
- '-k', dtb])
+ 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 fp:
+ root, strblock = vboot_forge.read_fdt(fp)
+ root, strblock = vboot_forge.manipulate(root, strblock)
+ with open(fit, 'w+b') as fp:
+ vboot_forge.write_fdt(root, strblock, fp)
+ 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)
+ 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' %
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')
+ 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):
+ """Test verified boot with the given hash algorithm.
+
+ This function test if u-boot reject 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.
+ """
+ # 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 with prod key (keys required)
+ # Build the FIT with dev key (keys NOT required)
+ # The dtb contain the key prod and dev and the key prod are set as required.
+ # Then try to boot the FIT with dev key
+ # This FIT should not be accepted by u-boot because the key prod is required
+ cons.log.action('%s: Test FIT with configs images' % sha_algo)
+ make_fit('sign-configs-%s%s-prod.its' % (sha_algo , padding))
+ sign_fit(sha_algo)
+ make_fit('sign-configs-%s%s.its' % (sha_algo , padding))
+ sign_fit(sha_algo)
+
+ run_bootm(sha_algo, 'signed configs', '', False)
+
cons = u_boot_console
tmpdir = cons.config.result_dir + '/'
tmp = tmpdir + 'vboot.tmp'
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@1'
+ sig_node = '/configurations/conf-1/signature'
# Create an RSA key pair
public_exponent = 65537
util.run_and_log(cons, 'openssl genpkey -algorithm RSA -out %sdev.key '
'-pkeyopt rsa_keygen_bits:2048 '
- '-pkeyopt rsa_keygen_pubexp:%d '
- '2>/dev/null' % (tmpdir, public_exponent))
+ '-pkeyopt rsa_keygen_pubexp:%d' %
+ (tmpdir, public_exponent))
# Create a certificate containing the public key
util.run_and_log(cons, 'openssl req -batch -new -x509 -key %sdev.key -out '
'%sdev.crt' % (tmpdir, tmpdir))
+ # Create an RSA key pair (prod)
+ public_exponent = 65537
+ util.run_and_log(cons, 'openssl genpkey -algorithm RSA -out %sprod.key '
+ '-pkeyopt rsa_keygen_bits:2048 '
+ '-pkeyopt rsa_keygen_pubexp:%d' %
+ (tmpdir, public_exponent))
+
+ # Create a certificate containing the public key (prod)
+ util.run_and_log(cons, 'openssl req -batch -new -x509 -key %sprod.key -out '
+ '%sprod.crt' % (tmpdir, tmpdir))
+
# Create a number kernel image with zeroes
with open('%stest-kernel.bin' % tmpdir, 'w') as fd:
fd.write(5000 * chr(0))
# afterwards.
old_dtb = cons.config.dtb
cons.config.dtb = dtb
- test_with_algo('sha1')
- test_with_algo('sha256')
+ if required:
+ test_required_key(sha_algo, padding)
+ else:
+ test_with_algo(sha_algo, padding)
finally:
# Go back to the original U-Boot with the correct dtb.
cons.config.dtb = old_dtb
projects / oweals / u-boot.git / blobdiff