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test: Add tests for the 'evil' vboot attacks
Add tests to check that these two attacks are mitigated by recent patches. Signed-off-by: Simon Glass <sjg@chromium.org> Reported-by: Bruce Monroe <bruce.monroe@intel.com> Reported-by: Arie Haenel <arie.haenel@intel.com> Reported-by: Julien Lenoir <julien.lenoir@intel.com>
This commit is contained in:
Simon Glass
Tom Rini
parent
fafafacb47
commit
d5f3aadacb
1 changed files with 64 additions and 27 deletions
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@ -24,22 +24,26 @@ For configuration verification:
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Tests run with both SHA1 and SHA256 hashing.
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"""
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import shutil
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import struct
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import pytest
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import u_boot_utils as util
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import vboot_forge
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import vboot_evil
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# Only run the full suite on a few combinations, since it doesn't add any more
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# test coverage.
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TESTDATA = [
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['sha1', '', None, False],
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['sha1', '', '-E -p 0x10000', False],
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['sha1', '-pss', None, False],
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['sha1', '-pss', '-E -p 0x10000', False],
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['sha256', '', None, False],
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['sha256', '', '-E -p 0x10000', False],
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['sha256', '-pss', None, False],
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['sha256', '-pss', '-E -p 0x10000', False],
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['sha256', '-pss', None, True],
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['sha256', '-pss', '-E -p 0x10000', True],
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['sha1', '', None, False, True],
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['sha1', '', '-E -p 0x10000', False, False],
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['sha1', '-pss', None, False, False],
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['sha1', '-pss', '-E -p 0x10000', False, False],
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['sha256', '', None, False, False],
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['sha256', '', '-E -p 0x10000', False, False],
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['sha256', '-pss', None, False, False],
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['sha256', '-pss', '-E -p 0x10000', False, False],
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['sha256', '-pss', None, True, False],
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['sha256', '-pss', '-E -p 0x10000', True, True],
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]
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@pytest.mark.boardspec('sandbox')
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@ -48,8 +52,10 @@ TESTDATA = [
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@pytest.mark.requiredtool('fdtget')
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@pytest.mark.requiredtool('fdtput')
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@pytest.mark.requiredtool('openssl')
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@pytest.mark.parametrize("sha_algo,padding,sign_options,required", TESTDATA)
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def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
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@pytest.mark.parametrize("sha_algo,padding,sign_options,required,full_test",
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TESTDATA)
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def test_vboot(u_boot_console, sha_algo, padding, sign_options, required,
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full_test):
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"""Test verified boot signing with mkimage and verification with 'bootm'.
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This works using sandbox only as it needs to update the device tree used
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@ -71,7 +77,7 @@ def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
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util.run_and_log(cons, 'dtc %s %s%s -O dtb '
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'-o %s%s' % (dtc_args, datadir, dts, tmpdir, dtb))
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def run_bootm(sha_algo, test_type, expect_string, boots):
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def run_bootm(sha_algo, test_type, expect_string, boots, fit=None):
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"""Run a 'bootm' command U-Boot.
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This always starts a fresh U-Boot instance since the device tree may
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@ -84,11 +90,14 @@ def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
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use.
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boots: A boolean that is True if Linux should boot and False if
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we are expected to not boot
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fit: FIT filename to load and verify
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"""
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if not fit:
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fit = '%stest.fit' % tmpdir
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cons.restart_uboot()
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with cons.log.section('Verified boot %s %s' % (sha_algo, test_type)):
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output = cons.run_command_list(
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['host load hostfs - 100 %stest.fit' % tmpdir,
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['host load hostfs - 100 %s' % fit,
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'fdt addr 100',
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'bootm 100'])
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assert expect_string in ''.join(output)
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@ -222,18 +231,41 @@ def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
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util.run_and_log(cons, [fit_check_sign, '-f', fit, '-k', dtb])
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# Make sure that U-Boot checks that the config is in the list of hashed
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# nodes. If it isn't, a security bypass is possible.
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with open(fit, 'rb') as fd:
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root, strblock = vboot_forge.read_fdt(fd)
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root, strblock = vboot_forge.manipulate(root, strblock)
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with open(fit, 'w+b') as fd:
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vboot_forge.write_fdt(root, strblock, fd)
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util.run_and_log_expect_exception(
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cons, [fit_check_sign, '-f', fit, '-k', dtb],
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1, 'Failed to verify required signature')
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if full_test:
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# Make sure that U-Boot checks that the config is in the list of hashed
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# nodes. If it isn't, a security bypass is possible.
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ffit = '%stest.forged.fit' % tmpdir
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shutil.copyfile(fit, ffit)
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with open(ffit, 'rb') as fd:
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root, strblock = vboot_forge.read_fdt(fd)
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root, strblock = vboot_forge.manipulate(root, strblock)
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with open(ffit, 'w+b') as fd:
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vboot_forge.write_fdt(root, strblock, fd)
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util.run_and_log_expect_exception(
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cons, [fit_check_sign, '-f', ffit, '-k', dtb],
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1, 'Failed to verify required signature')
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run_bootm(sha_algo, 'forged config', 'Bad Data Hash', False)
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run_bootm(sha_algo, 'forged config', 'Bad Data Hash', False, ffit)
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# Try adding an evil root node. This should be detected.
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efit = '%stest.evilf.fit' % tmpdir
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shutil.copyfile(fit, efit)
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vboot_evil.add_evil_node(fit, efit, evil_kernel, 'fakeroot')
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util.run_and_log_expect_exception(
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cons, [fit_check_sign, '-f', efit, '-k', dtb],
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1, 'Failed to verify required signature')
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run_bootm(sha_algo, 'evil fakeroot', 'Bad Data Hash', False, efit)
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# Try adding an @ to the kernel node name. This should be detected.
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efit = '%stest.evilk.fit' % tmpdir
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shutil.copyfile(fit, efit)
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vboot_evil.add_evil_node(fit, efit, evil_kernel, 'kernel@')
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util.run_and_log_expect_exception(
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cons, [fit_check_sign, '-f', efit, '-k', dtb],
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1, 'Node name contains @')
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run_bootm(sha_algo, 'evil kernel@', 'Bad Data Hash', False, efit)
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# Create a new properly signed fit and replace header bytes
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make_fit('sign-configs-%s%s.its' % (sha_algo, padding))
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@ -344,8 +376,13 @@ def test_vboot(u_boot_console, sha_algo, padding, sign_options, required):
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create_rsa_pair('prod')
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# Create a number kernel image with zeroes
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with open('%stest-kernel.bin' % tmpdir, 'w') as fd:
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fd.write(500 * chr(0))
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with open('%stest-kernel.bin' % tmpdir, 'wb') as fd:
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fd.write(500 * b'\0')
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# Create a second kernel image with ones
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evil_kernel = '%stest-kernel1.bin' % tmpdir
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with open(evil_kernel, 'wb') as fd:
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fd.write(500 * b'\x01')
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try:
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# We need to use our own device tree file. Remember to restore it
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