1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2022 Massimo Pegorer
"""
Test that mkimage generates auto-FIT with signatures and/or hashes as expected.
The mkimage tool can create auto generated (i.e. without an ITS file
provided as input) FIT in three different flavours: with crc32 checksums
of 'images' subnodes; with signatures of 'images' subnodes; with sha1
hashes of 'images' subnodes and signatures of 'configurations' subnodes.
This test verifies that auto-FIT are generated as expected, in all of
the three flavours, including check of hashes and signatures (except for
configurations ones).
The test does not run the sandbox. It only checks the host tool mkimage.
"""
import os
import pytest
import u_boot_utils as util
import binascii
from Cryptodome.Hash import SHA1
from Cryptodome.Hash import SHA256
from Cryptodome.PublicKey import RSA
from Cryptodome.Signature import pkcs1_15
class SignedFitHelper(object):
"""Helper to manipulate a FIT with signed/hashed images/configs."""
def __init__(self, cons, file_name):
self.fit = file_name
self.cons = cons
self.images_nodes = set()
self.confgs_nodes = set()
def __fdt_list(self, path):
return util.run_and_log(self.cons,
f'fdtget -l {self.fit} {path}')
def __fdt_get_string(self, node, prop):
return util.run_and_log(self.cons,
f'fdtget -ts {self.fit} {node} {prop}')
def __fdt_get_binary(self, node, prop):
numbers = util.run_and_log(self.cons,
f'fdtget -tbi {self.fit} {node} {prop}')
bignum = bytearray()
for little_num in numbers.split():
bignum.append(int(little_num))
return bignum
def build_nodes_sets(self):
"""Fill sets with FIT images and configurations subnodes."""
for node in self.__fdt_list('/images').split():
subnode = f'/images/{node}'
self.images_nodes.add(subnode)
for node in self.__fdt_list('/configurations').split():
subnode = f'/configurations/{node}'
self.confgs_nodes.add(subnode)
return len(self.images_nodes) + len(self.confgs_nodes)
def check_fit_crc32_images(self):
"""Test that all images in the set are hashed as expected.
Each image must have an hash with algo=crc32 and hash value must match
the one calculated over image data.
"""
for node in self.images_nodes:
algo = self.__fdt_get_string(f'{node}/hash', 'algo')
assert algo == "crc32\n", "Missing expected crc32 image hash!"
raw_crc32 = self.__fdt_get_binary(f'{node}/hash', 'value')
raw_bin = self.__fdt_get_binary(node, 'data')
assert raw_crc32 == (binascii.crc32(raw_bin) &
0xffffffff).to_bytes(4, 'big'), "Wrong crc32 hash!"
def check_fit_signed_images(self, key_name, sign_algo, verifier):
"""Test that all images in the set are signed as expected.
Each image must have a signature with: key-name-hint matching key_name
argument; algo matching sign_algo argument; value matching the one
calculated over image data using verifier argument.
"""
for node in self.images_nodes:
hint = self.__fdt_get_string(f'{node}/signature', 'key-name-hint')
assert hint == key_name + "\n", "Missing expected key name hint!"
algo = self.__fdt_get_string(f'{node}/signature', 'algo')
assert algo == sign_algo + "\n", "Missing expected signature algo!"
raw_sig = self.__fdt_get_binary(f'{node}/signature', 'value')
raw_bin = self.__fdt_get_binary(node, 'data')
verifier.verify(SHA256.new(raw_bin), bytes(raw_sig))
def check_fit_signed_confgs(self, key_name, sign_algo):
"""Test that all configs are signed, and images hashed, as expected.
Each image must have an hash with algo=sha1 and hash value must match
the one calculated over image data. Each configuration must have a
signature with key-name-hint matching key_name argument and algo
matching sign_algo argument.
TODO: configurations signature checking.
"""
for node in self.images_nodes:
algo = self.__fdt_get_string(f'{node}/hash', 'algo')
assert algo == "sha1\n", "Missing expected sha1 image hash!"
raw_hash = self.__fdt_get_binary(f'{node}/hash', 'value')
raw_bin = self.__fdt_get_binary(node, 'data')
assert raw_hash == SHA1.new(raw_bin).digest(), "Wrong sha1 hash!"
for node in self.confgs_nodes:
hint = self.__fdt_get_string(f'{node}/signature', 'key-name-hint')
assert hint == key_name + "\n", "Missing expected key name hint!"
algo = self.__fdt_get_string(f'{node}/signature', 'algo')
assert algo == sign_algo + "\n", "Missing expected signature algo!"
@pytest.mark.buildconfigspec('fit_signature')
@pytest.mark.requiredtool('fdtget')
def test_fit_auto_signed(u_boot_console):
"""Test that mkimage generates auto-FIT with signatures/hashes as expected.
The mkimage tool can create auto generated (i.e. without an ITS file
provided as input) FIT in three different flavours: with crc32 checksums
of 'images' subnodes; with signatures of 'images' subnodes; with sha1
hashes of 'images' subnodes and signatures of 'configurations' subnodes.
This test verifies that auto-FIT are generated as expected, in all of
the three flavours, including check of hashes and signatures (except for
configurations ones).
The test does not run the sandbox. It only checks the host tool mkimage.
"""
cons = u_boot_console
mkimage = cons.config.build_dir + '/tools/mkimage'
tempdir = os.path.join(cons.config.result_dir, 'auto_fit')
os.makedirs(tempdir, exist_ok=True)
kernel_file = f'{tempdir}/vmlinuz'
dt1_file = f'{tempdir}/dt-1.dtb'
dt2_file = f'{tempdir}/dt-2.dtb'
key_name = 'sign-key'
sign_algo = 'sha256,rsa4096'
key_file = f'{tempdir}/{key_name}.key'
fit_file = f'{tempdir}/test.fit'
# Create a fake kernel image and two dtb files with random data
with open(kernel_file, 'wb') as fd:
fd.write(os.urandom(512))
with open(dt1_file, 'wb') as fd:
fd.write(os.urandom(256))
with open(dt2_file, 'wb') as fd:
fd.write(os.urandom(256))
# Create 4096 RSA key and write to file to be read by mkimage
key = RSA.generate(bits=4096)
verifier = pkcs1_15.new(key)
with open(key_file, 'w') as fd:
fd.write(str(key.export_key(format='PEM').decode('ascii')))
b_args = " -d" + kernel_file + " -b" + dt1_file + " -b" + dt2_file
s_args = " -k" + tempdir + " -g" + key_name + " -o" + sign_algo
# 1 - Create auto FIT with images crc32 checksum, and verify it
util.run_and_log(cons, mkimage + ' -fauto' + b_args + " " + fit_file)
fit = SignedFitHelper(cons, fit_file)
if fit.build_nodes_sets() == 0:
raise ValueError('FIT-1 has no "/image" nor "/configuration" nodes')
fit.check_fit_crc32_images()
# 2 - Create auto FIT with signed images, and verify it
util.run_and_log(cons, mkimage + ' -fauto' + b_args + s_args + " " +
fit_file)
fit = SignedFitHelper(cons, fit_file)
if fit.build_nodes_sets() == 0:
raise ValueError('FIT-2 has no "/image" nor "/configuration" nodes')
fit.check_fit_signed_images(key_name, sign_algo, verifier)
# 3 - Create auto FIT with signed configs and hashed images, and verify it
util.run_and_log(cons, mkimage + ' -fauto-conf' + b_args + s_args + " " +
fit_file)
fit = SignedFitHelper(cons, fit_file)
if fit.build_nodes_sets() == 0:
raise ValueError('FIT-3 has no "/image" nor "/configuration" nodes')
fit.check_fit_signed_confgs(key_name, sign_algo)
|