[PATCH v4 7/7] test/py: efi_secboot: add test for intermediate certificates

Heinrich Schuchardt
2020-07-17T10:29:06Z

On 17.07.20 09:16, AKASHI Takahiro wrote:
> In this test case, an image may have a signature with additional
> intermediate certificates. A chain of trust will be followed and all
> the certificates in the middle of chain must be verified before loading.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Thanks for providing all these tests and for rebasing on 53ce9a6ed98b6
("test: use virt-make-fs to build image").

Essentially this patch could have been split into two:

* style corrections for existing code
* new tests

Unfortunatly the setup not working correctly. 'make tests' shows:

test/py/tests/test_efi_secboot/test_authvar.py FFFFF
test/py/tests/test_efi_secboot/test_signed.py .F..FF
test/py/tests/test_efi_secboot/test_signed_intca.py sss
test/py/tests/test_efi_secboot/test_unsigned.py ...

SKIPPED [3] test/py/tests/test_efi_secboot/conftest.py:254: Setup
failed: cd build-sandbox/mnt_efisecure; sbsign --key TestCert.key --cert
TestCert.crt --addcert TestSub.crt --out helloworld.efi.signed_ab
helloworld.efi

If you replace as follows in test/run you get the extra skip messages:

%s/--bd/-ra --bd/g

> ---
> test/py/tests/test_efi_secboot/conftest.py | 134 ++++++++++++++++-
> test/py/tests/test_efi_secboot/defs.py | 8 +-
> test/py/tests/test_efi_secboot/openssl.cnf | 48 +++++++
> .../test_efi_secboot/test_signed_intca.py | 135 ++++++++++++++++++
> 4 files changed, 317 insertions(+), 8 deletions(-)
> create mode 100644 test/py/tests/test_efi_secboot/openssl.cnf
> create mode 100644 test/py/tests/test_efi_secboot/test_signed_intca.py
>
> diff --git a/test/py/tests/test_efi_secboot/conftest.py b/test/py/tests/test_efi_secboot/conftest.py
> index c6709700a876..20d0cbf3ab01 100644
> --- a/test/py/tests/test_efi_secboot/conftest.py
> +++ b/test/py/tests/test_efi_secboot/conftest.py
> @@ -37,7 +37,7 @@ def efi_boot_env(request, u_boot_config):
> global HELLO_PATH
>
> image_path = u_boot_config.persistent_data_dir
> - image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME
> + image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME + '.img'

I would prefer a separate constant for
EFI_SECBOOT_IMAGE_NAME + '_intca.img'
to ensure that conftest.py and test_signed_intca.py use the same value.

>
> if HELLO_PATH == '':

Shouldn't we set HELLO_PATH = 'lib/efi_loader/helloworld.efi' in defs.py
and use another variable name here?

bin_path = u_boot_config.build_dir + '/' + HELLO_PATH

> HELLO_PATH = u_boot_config.build_dir + '/lib/efi_loader/helloworld.efi'

Capitalization should only be used for constants.

Best regards

Heinrich

> @@ -87,21 +87,21 @@ def efi_boot_env(request, u_boot_config):
> # db1-update
> check_call('cd %s; %ssign-efi-sig-list -t "2020-04-06" -a -c KEK.crt -k KEK.key db db1.esl db1-update.auth'
> % (mnt_point, EFITOOLS_PATH), shell=True)
> - ## dbx (TEST_dbx certificate)
> + # dbx (TEST_dbx certificate)
> check_call('cd %s; openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_dbx/ -keyout dbx.key -out dbx.crt -nodes -days 365'
> % mnt_point, shell=True)
> check_call('cd %s; %scert-to-efi-sig-list -g %s dbx.crt dbx.esl; %ssign-efi-sig-list -t "2020-04-05" -c KEK.crt -k KEK.key dbx dbx.esl dbx.auth'
> % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> shell=True)
> - ## dbx_hash (digest of TEST_db certificate)
> + # dbx_hash (digest of TEST_db certificate)
> check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 db.crt dbx_hash.crl; %ssign-efi-sig-list -t "2020-04-05" -c KEK.crt -k KEK.key dbx dbx_hash.crl dbx_hash.auth'
> % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> shell=True)
> - ## dbx_hash1 (digest of TEST_db1 certificate)
> + # dbx_hash1 (digest of TEST_db1 certificate)
> check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 db1.crt dbx_hash1.crl; %ssign-efi-sig-list -t "2020-04-05" -c KEK.crt -k KEK.key dbx dbx_hash1.crl dbx_hash1.auth'
> % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> shell=True)
> - ## dbx_db (with TEST_db certificate)
> + # dbx_db (with TEST_db certificate)
> check_call('cd %s; %ssign-efi-sig-list -t "2020-04-05" -c KEK.crt -k KEK.key dbx db.esl dbx_db.auth'
> % (mnt_point, EFITOOLS_PATH),
> shell=True)
> @@ -112,10 +112,10 @@ def efi_boot_env(request, u_boot_config):
> # Sign image
> check_call('cd %s; sbsign --key db.key --cert db.crt helloworld.efi'
> % mnt_point, shell=True)
> - ## Sign already-signed image with another key
> + # Sign already-signed image with another key
> check_call('cd %s; sbsign --key db1.key --cert db1.crt --output helloworld.efi.signed_2sigs helloworld.efi.signed'
> % mnt_point, shell=True)
> - ## Digest image
> + # Digest image
> check_call('cd %s; %shash-to-efi-sig-list helloworld.efi db_hello.hash; %ssign-efi-sig-list -t "2020-04-07" -c KEK.crt -k KEK.key db db_hello.hash db_hello.auth'
> % (mnt_point, EFITOOLS_PATH, EFITOOLS_PATH),
> shell=True)
> @@ -136,3 +136,123 @@ def efi_boot_env(request, u_boot_config):
> yield image_path
> finally:
> call('rm -f %s' % image_path, shell=True)
> +
> +#
> +# Fixture for UEFI secure boot test of intermediate certificates
> +#
> +
> +
> + at pytest.fixture(scope='session')
> +def efi_boot_env_intca(request, u_boot_config):
> + """Set up a file system to be used in UEFI secure boot test
> + of intermediate certificates.
> +
> + Args:
> + request: Pytest request object.
> + u_boot_config: U-boot configuration.
> +
> + Return:
> + A path to disk image to be used for testing
> + """
> + global HELLO_PATH
> +
> + image_path = u_boot_config.persistent_data_dir
> + image_path = image_path + '/' + EFI_SECBOOT_IMAGE_NAME + '_intca.img'
> +
> + if HELLO_PATH == '':

See comment above.

> + HELLO_PATH = u_boot_config.build_dir + '/lib/efi_loader/helloworld.efi'

Capitalization should only be used for constants.

> +
> + try:
> + mnt_point = u_boot_config.build_dir + '/mnt_efisecure'
> + check_call('rm -rf {}'.format(mnt_point), shell=True)
> + check_call('mkdir -p {}'.format(mnt_point), shell=True)
> +
> + # Create signature database
> + # PK
> + check_call('cd %s; openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_PK/ -keyout PK.key -out PK.crt -nodes -days 365'
> + % mnt_point, shell=True)
> + check_call('cd %s; %scert-to-efi-sig-list -g %s PK.crt PK.esl; %ssign-efi-sig-list -c PK.crt -k PK.key PK PK.esl PK.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> + # KEK
> + check_call('cd %s; openssl req -x509 -sha256 -newkey rsa:2048 -subj /CN=TEST_KEK/ -keyout KEK.key -out KEK.crt -nodes -days 365'
> + % mnt_point, shell=True)
> + check_call('cd %s; %scert-to-efi-sig-list -g %s KEK.crt KEK.esl; %ssign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl KEK.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> +
> + # We will have three-tier hierarchy of certificates:
> + # TestRoot: Root CA (self-signed)
> + # TestSub: Intermediate CA (signed by Root CA)
> + # TestCert: User certificate (signed by Intermediate CA, and used
> + # for signing an image)
> + #
> + # NOTE:
> + # I consulted the following EDK2 document for certificate options:
> + # BaseTools/Source/Python/Pkcs7Sign/Readme.md
> + # Please not use them as they are in product system. They are
> + # for test purpose only.
> +
> + # TestRoot
> + check_call('cp %s/test/py/tests/test_efi_secboot/openssl.cnf %s'
> + % (u_boot_config.source_dir, mnt_point), shell=True)
> + check_call('cd %s; openssl genrsa -out TestRoot.key 2048; openssl req --config openssl.cnf -extensions v3_ca -new -x509 -days 365 -key TestRoot.key -out TestRoot.crt -subj "/CN=TEST_root/"; touch index.txt'
> + % mnt_point, shell=True)
> + # TestSub
> + check_call('cd %s; openssl genrsa -out TestSub.key 2048; openssl req -new -key TestSub.key -out TestSub.csr -subj "/CN=TEST_sub/"; openssl ca --config openssl.cnf -in TestSub.csr -out TestSub.crt -extensions v3_int_ca -days 365 -batch -rand_serial -cert TestRoot.crt -keyfile TestRoot.key'
> + % mnt_point, shell=True)
> + # TestCert
> + check_call('cd %s; openssl genrsa -out TestCert.key 2048; openssl req -new -key TestCert.key -out TestCert.csr -subj "/CN=TEST_cert/"; openssl ca --config openssl.cnf -in TestCert.csr -out TestCert.crt -extensions usr_cert -days 365 -batch -rand_serial -cert TestSub.crt -keyfile TestSub.key'
> + % mnt_point, shell=True)
> + # db
> + # for TestCert
> + check_call('cd %s; %scert-to-efi-sig-list -g %s TestCert.crt TestCert.esl; %ssign-efi-sig-list -c KEK.crt -k KEK.key db TestCert.esl db_a.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> + # for TestSub
> + check_call('cd %s; %scert-to-efi-sig-list -g %s TestSub.crt TestSub.esl; %ssign-efi-sig-list -t "2020-07-16" -c KEK.crt -k KEK.key db TestSub.esl db_b.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> + # for TestRoot
> + check_call('cd %s; %scert-to-efi-sig-list -g %s TestRoot.crt TestRoot.esl; %ssign-efi-sig-list -t "2020-07-17" -c KEK.crt -k KEK.key db TestRoot.esl db_c.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> + ## dbx (hash of certificate with revocation time)
> + # for TestCert
> + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestCert.crt TestCert.crl; %ssign-efi-sig-list -c KEK.crt -k KEK.key dbx TestCert.crl dbx_a.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)

Not to be corrected in this patch:

-t 0 means revocation for all times.

Shouldn't we have a test that checks that revocation time stamps are
correctly used? As we use explicit timestamps now for sign-efi-sig-list
this should be feasible.

> + # for TestSub
> + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestSub.crt TestSub.crl; %ssign-efi-sig-list -t "2020-07-18" -c KEK.crt -k KEK.key dbx TestSub.crl dbx_b.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> + # for TestRoot
> + check_call('cd %s; %scert-to-efi-hash-list -g %s -t 0 -s 256 TestRoot.crt TestRoot.crl; %ssign-efi-sig-list -t "2020-07-19" -c KEK.crt -k KEK.key dbx TestRoot.crl dbx_c.auth'
> + % (mnt_point, EFITOOLS_PATH, GUID, EFITOOLS_PATH),
> + shell=True)
> +
> + # Sign image
> + # additional intermediate certificates may be included
> + # in SignedData
> +
> + check_call('cp %s %s' % (HELLO_PATH, mnt_point), shell=True)
> + # signed by TestCert
> + check_call('cd %s; %ssbsign --key TestCert.key --cert TestCert.crt --out helloworld.efi.signed_a helloworld.efi'
> + % (mnt_point, SBSIGN_PATH), shell=True)
> + # signed by TestCert with TestSub in signature
> + check_call('cd %s; %ssbsign --key TestCert.key --cert TestCert.crt --addcert TestSub.crt --out helloworld.efi.signed_ab helloworld.efi'
> + % (mnt_point, SBSIGN_PATH), shell=True)
> + # signed by TestCert with TestSub and TestRoot in signature
> + check_call('cd %s; cat TestSub.crt TestRoot.crt > TestSubRoot.crt; %ssbsign --key TestCert.key --cert TestCert.crt --addcert TestSubRoot.crt --out helloworld.efi.signed_abc helloworld.efi'
> + % (mnt_point, SBSIGN_PATH), shell=True)
> +
> + check_call('virt-make-fs --partition=gpt --size=+1M --type=vfat {} {}'.format(mnt_point, image_path), shell=True)
> + check_call('rm -rf {}'.format(mnt_point), shell=True)
> +
> + except CalledProcessError as e:
> + pytest.skip('Setup failed: %s' % e.cmd)
> + return
> + else:
> + yield image_path
> + finally:
> + call('rm -f %s' % image_path, shell=True)
> diff --git a/test/py/tests/test_efi_secboot/defs.py b/test/py/tests/test_efi_secboot/defs.py
> index ba6b9f391e60..a26bbc103cd9 100644
> --- a/test/py/tests/test_efi_secboot/defs.py
> +++ b/test/py/tests/test_efi_secboot/defs.py
> @@ -1,14 +1,20 @@
> # SPDX-License-Identifier: GPL-2.0+
>
> # Disk image name
> -EFI_SECBOOT_IMAGE_NAME = 'test_efi_secboot.img'
> +EFI_SECBOOT_IMAGE_NAME = 'test_efi_secboot'
>
> # Owner guid
> GUID = '11111111-2222-3333-4444-123456789abc'
>
> # v1.5.1 or earlier of efitools has a bug in sha256 calculation, and
> # you need build a newer version on your own.
> +# The path must terminate with '/'.
> EFITOOLS_PATH = ''
>
> +# "--addcert" option of sbsign must be available, otherwise
> +# you need build a newer version on your own.
> +# The path must terminate with '/'.
> +SBSIGN_PATH = ''
> +
> # Hello World application for sandbox
> HELLO_PATH = ''
> diff --git a/test/py/tests/test_efi_secboot/openssl.cnf b/test/py/tests/test_efi_secboot/openssl.cnf
> new file mode 100644
> index 000000000000..f684f1df7e69
> --- /dev/null
> +++ b/test/py/tests/test_efi_secboot/openssl.cnf
> @@ -0,0 +1,48 @@
> +[ ca ]
> +default_ca = CA_default
> +
> +[ CA_default ]
> +new_certs_dir = .
> +database = ./index.txt
> +serial = ./serial
> +default_md = sha256
> +policy = policy_min
> +
> +[ req ]
> +distinguished_name = def_distinguished_name
> +
> +[def_distinguished_name]
> +
> +# Extensions
> +# -addext " ... = ..."
> +#
> +[ v3_ca ]
> + # Extensions for a typical Root CA.
> + basicConstraints = critical,CA:TRUE
> + keyUsage = critical, digitalSignature, cRLSign, keyCertSign
> + subjectKeyIdentifier = hash
> + authorityKeyIdentifier = keyid:always,issuer
> +
> +[ v3_int_ca ]
> + # Extensions for a typical intermediate CA.
> + basicConstraints = critical, CA:TRUE
> + keyUsage = critical, digitalSignature, cRLSign, keyCertSign
> + subjectKeyIdentifier = hash
> + authorityKeyIdentifier = keyid:always,issuer
> +
> +[ usr_cert ]
> + # Extensions for user end certificates.
> + basicConstraints = CA:FALSE
> + keyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment
> + extendedKeyUsage = clientAuth, emailProtection
> + subjectKeyIdentifier = hash
> + authorityKeyIdentifier = keyid,issuer
> +
> +[ policy_min ]
> + countryName = optional
> + stateOrProvinceName = optional
> + localityName = optional
> + organizationName = optional
> + organizationalUnitName = optional
> + commonName = supplied
> + emailAddress = optional
> diff --git a/test/py/tests/test_efi_secboot/test_signed_intca.py b/test/py/tests/test_efi_secboot/test_signed_intca.py
> new file mode 100644
> index 000000000000..1240174758cf
> --- /dev/null
> +++ b/test/py/tests/test_efi_secboot/test_signed_intca.py
> @@ -0,0 +1,135 @@
> +# SPDX-License-Identifier: GPL-2.0+
> +# Copyright (c) 2020, Linaro Limited
> +# Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
> +#
> +# U-Boot UEFI: Image Authentication Test (signature with certificates chain)
> +
> +"""
> +This test verifies image authentication for a signed image which is signed
> +by user certificate and contains additional intermediate certificates in its
> +signature.
> +"""
> +
> +import pytest
> +
> +
> + at pytest.mark.boardspec('sandbox')
> + at pytest.mark.buildconfigspec('efi_secure_boot')
> + at pytest.mark.buildconfigspec('cmd_efidebug')
> + at pytest.mark.buildconfigspec('cmd_fat')
> + at pytest.mark.buildconfigspec('cmd_nvedit_efi')
> + at pytest.mark.slow
> +class TestEfiSignedImageExt(object):
> + def test_efi_signed_image_ext1(self, u_boot_console, efi_boot_env_intca):
> + """
> + Test Case 1 - authenticated by root CA in db
> + """
> + u_boot_console.restart_uboot()
> + disk_img = efi_boot_env_intca
> + with u_boot_console.log.section('Test Case 1a'):
> + # Test Case 1a, with no Int CA and not authenticated by root CA
> + output = u_boot_console.run_command_list([
> + 'host bind 0 %s' % disk_img,
> + 'fatload host 0:1 4000000 db_c.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db',
> + 'fatload host 0:1 4000000 KEK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK',
> + 'fatload host 0:1 4000000 PK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK'])
> + assert 'Failed to set EFI variable' not in ''.join(output)
> +
> + output = u_boot_console.run_command_list([
> + 'efidebug boot add 1 HELLO_a host 0:1 /helloworld.efi.signed_a ""',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert '\'HELLO_a\' failed' in ''.join(output)
> + assert 'efi_start_image() returned: 26' in ''.join(output)
> +
> + with u_boot_console.log.section('Test Case 1b'):
> + # Test Case 1b, signed and authenticated by root CA
> + output = u_boot_console.run_command_list([
> + 'efidebug boot add 2 HELLO_ab host 0:1 /helloworld.efi.signed_ab ""',
> + 'efidebug boot next 2',
> + 'bootefi bootmgr'])
> + assert 'Hello, world!' in ''.join(output)
> +
> + def test_efi_signed_image_ext2(self, u_boot_console, efi_boot_env_intca):
> + """
> + Test Case 2 - authenticated by root CA in db
> + """
> + u_boot_console.restart_uboot()
> + disk_img = efi_boot_env_intca
> + with u_boot_console.log.section('Test Case 2a'):
> + # Test Case 2a, unsigned and not authenticated by root CA
> + output = u_boot_console.run_command_list([
> + 'host bind 0 %s' % disk_img,
> + 'fatload host 0:1 4000000 KEK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK',
> + 'fatload host 0:1 4000000 PK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK'])
> + assert 'Failed to set EFI variable' not in ''.join(output)
> +
> + output = u_boot_console.run_command_list([
> + 'efidebug boot add 1 HELLO_abc host 0:1 /helloworld.efi.signed_abc ""',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert '\'HELLO_abc\' failed' in ''.join(output)
> + assert 'efi_start_image() returned: 26' in ''.join(output)
> +
> + with u_boot_console.log.section('Test Case 2b'):
> + # Test Case 2b, signed and authenticated by root CA
> + output = u_boot_console.run_command_list([
> + 'fatload host 0:1 4000000 db_b.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert '\'HELLO_abc\' failed' in ''.join(output)
> + assert 'efi_start_image() returned: 26' in ''.join(output)
> +
> + with u_boot_console.log.section('Test Case 2c'):
> + # Test Case 2c, signed and authenticated by root CA
> + output = u_boot_console.run_command_list([
> + 'fatload host 0:1 4000000 db_c.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert 'Hello, world!' in ''.join(output)
> +
> + def test_efi_signed_image_ext3(self, u_boot_console, efi_boot_env_intca):
> + """
> + Test Case 3 - revoked by dbx
> + """
> + u_boot_console.restart_uboot()
> + disk_img = efi_boot_env_intca
> + with u_boot_console.log.section('Test Case 3a'):
> + # Test Case 3a, revoked by int CA in dbx
> + output = u_boot_console.run_command_list([
> + 'host bind 0 %s' % disk_img,
> + 'fatload host 0:1 4000000 dbx_b.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize dbx',
> + 'fatload host 0:1 4000000 db_c.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize db',
> + 'fatload host 0:1 4000000 KEK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize KEK',
> + 'fatload host 0:1 4000000 PK.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize PK'])
> + assert 'Failed to set EFI variable' not in ''.join(output)
> +
> + output = u_boot_console.run_command_list([
> + 'efidebug boot add 1 HELLO_abc host 0:1 /helloworld.efi.signed_abc ""',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert 'Hello, world!' in ''.join(output)
> + # Or,
> + # assert '\'HELLO_abc\' failed' in ''.join(output)
> + # assert 'efi_start_image() returned: 26' in ''.join(output)
> +
> + with u_boot_console.log.section('Test Case 3b'):
> + # Test Case 3b, revoked by root CA in dbx
> + output = u_boot_console.run_command_list([
> + 'fatload host 0:1 4000000 dbx_c.auth',
> + 'setenv -e -nv -bs -rt -at -i 4000000,$filesize dbx',
> + 'efidebug boot next 1',
> + 'efidebug test bootmgr'])
> + assert '\'HELLO_abc\' failed' in ''.join(output)
> + assert 'efi_start_image() returned: 26' in ''.join(output)
>