esp-idf/tools/test_apps/security/secure_boot/example_test.py

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7.5 KiB
Python

from __future__ import print_function
import os
import struct
import zlib
from io import BytesIO
import ttfw_idf
# To prepare a runner for these tests,
# 1. Connect an FPGA with C3 image
# 2. Use a COM port for programming and export it as ESPPORT
# e.g export ESPPORT=/dev/ttyUSB0
# 3. Use another COM port for resetting efuses and connect its DTR pin to efuse reset pin on the FPGA board.
# Export it as EFUSEPORT
# e.g export EFUSEPORT=/dev/ttyUSB1
# 4. Run these tests
def corrupt_signature(signed_bootloader, seed=0, corrupt_sig=True, corrupt_crc=False, corrupt_single_block=None):
# type: (bytes, int, bool, bool, int) -> bytes
image = signed_bootloader[:-4096]
signature = signed_bootloader[-4096:]
sig_blocks = (signature[0:1216], signature[1216:2432], signature[2432:3648])
new_blocks = tuple(corrupt_sig_block(s, seed, corrupt_sig, corrupt_crc) for s in sig_blocks)
# if corrupt_single_block is None, corrupt all blocks
# otherwise, only corrupt the one with that index set
corr_sig_blocks = tuple(new_blocks[n] if corrupt_single_block in [None, n] else sig_blocks[n] for n in range(3))
return image + b''.join(corr_sig_blocks) + signature[3648:]
def corrupt_sig_block(sig_block, seed=0, corrupt_sig=True, corrupt_crc=False):
# type: (bytes, int, bool, bool) -> bytes
assert len(sig_block) == 1216
magic = sig_block[0]
assert magic in [0xe7, 0xff]
if magic != 0xe7:
return sig_block # not valid
data = sig_block[:812]
new_sig = sig = sig_block[812:1196]
crc = sig_block[1196:1200]
padding = sig_block[1200:1216]
if corrupt_sig:
corrupt_idx = seed % len(sig)
corrupt_delta = zlib.crc32(bytes(seed)) & 0xFF
if corrupt_delta == 0:
corrupt_delta = 1
new_byte = sig[corrupt_idx] ^ corrupt_delta
new_sig = sig[0:corrupt_idx] + bytes([new_byte]) + sig[corrupt_idx + 1:]
assert new_sig != sig
if not corrupt_crc:
crc = struct.pack('<I', zlib.crc32(data + new_sig) & 0xffffffff)
else:
crc = struct.pack('<I', zlib.crc32(crc))
result = data + new_sig + crc + padding
assert len(result) == len(sig_block)
return result
def dut_start_secure_app(dut): # type: (ttfw_idf.IDFDUT) -> None
dut.reset_efuses()
bootloader_bin = os.path.join(dut.app.binary_path, 'bootloader/bootloader.bin')
with open(bootloader_bin, 'rb') as f:
dut.write_flash_data([(0x0, f)], None, True, False)
dut.start_app()
# Test secure boot flow.
# Correctly signed bootloader + correctly signed app should work
@ttfw_idf.idf_custom_test(env_tag='Example_Secure_Boot', target=['esp32c3fpga', 'esp32s3fpga'], ignore=True)
def test_examples_security_secure_boot(env, _): # type: (ttfw_idf.TinyFW.Env, None) -> None
efuse_port = os.getenv('EFUSEPORT')
dut = env.get_dut('secure_boot', 'tools/test_apps/security/secure_boot', efuse_reset_port=efuse_port)
dut_start_secure_app(dut)
dut.expect('Secure Boot is enabled', timeout=2)
# Test efuse key index and key block combination.
# Any key index can be written to any key block and should work
@ttfw_idf.idf_custom_test(env_tag='Example_Secure_Boot', target=['esp32c3fpga', 'esp32s3fpga'], ignore=True)
def test_examples_security_secure_boot_key_combo(env, _): # type: (ttfw_idf.TinyFW.Env, None) -> None
efuse_port = os.getenv('EFUSEPORT')
dut = env.get_dut('secure_boot', 'tools/test_apps/security/secure_boot', efuse_reset_port=efuse_port)
dut_start_secure_app(dut)
for index in range(3):
for block in range(6):
dut.reset_efuses()
dut.secure_boot_burn_en_bit()
dut.secure_boot_burn_digest('test_rsa_3072_key.pem', index, block)
dut.reset()
dut.expect('Secure Boot is enabled', timeout=2)
# Test secure boot key revoke.
# If a key is revoked, bootloader signed with that key should fail verification
@ttfw_idf.idf_custom_test(env_tag='Example_Secure_Boot', target=['esp32c3fpga', 'esp32s3fpga'], ignore=True)
def test_examples_security_secure_boot_key_revoke(env, _): # type: (ttfw_idf.TinyFW.Env, None) -> None
efuse_port = os.getenv('EFUSEPORT')
dut = env.get_dut('secure_boot', 'tools/test_apps/security/secure_boot', efuse_reset_port=efuse_port)
dut_start_secure_app(dut)
for index in range(3):
dut.reset_efuses()
dut.secure_boot_burn_en_bit()
dut.secure_boot_burn_digest('test_rsa_3072_key.pem', index, 0)
dut.burn_efuse('SECURE_BOOT_KEY_REVOKE%d' % index, 1)
dut.reset()
dut.expect('secure boot verification failed', timeout=2)
# Test bootloader signature corruption.
# Corrupt one byte at a time of bootloader signature and test that the verification fails
@ttfw_idf.idf_custom_test(env_tag='Example_Secure_Boot', target=['esp32c3fpga', 'esp32s3fpga'], ignore=True)
def test_examples_security_secure_boot_corrupt_bl_sig(env, _): # type: (ttfw_idf.TinyFW.Env, None) -> None
efuse_port = os.getenv('EFUSEPORT')
dut = env.get_dut('secure_boot', 'tools/test_apps/security/secure_boot', efuse_reset_port=efuse_port)
dut.reset_efuses()
dut.secure_boot_burn_en_bit()
dut.secure_boot_burn_digest('test_rsa_3072_key.pem', 0, 0)
bootloader_bin = os.path.join(dut.app.binary_path, 'bootloader/bootloader.bin')
with open(bootloader_bin, 'rb') as f:
signed_bl = f.read()
seeds = range(0, 384)
max_seed = max(seeds)
for seed in seeds:
print('Case %d / %d' % (seed, max_seed))
corrupt_bl = corrupt_signature(signed_bl, seed=seed)
dut.write_flash_data([(0x0, BytesIO(corrupt_bl))])
dut.expect('Signature Check Failed', timeout=2)
# Test app signature corruption.
# Corrupt app signature, one byte at a time, and test that the verification fails
@ttfw_idf.idf_custom_test(env_tag='Example_Secure_Boot', target=['esp32c3fpga', 'esp32s3fpga'], ignore=True)
def test_examples_security_secure_boot_corrupt_app_sig(env, _): # type: (ttfw_idf.TinyFW.Env, None) -> None
efuse_port = os.getenv('EFUSEPORT')
dut = env.get_dut('secure_boot', 'tools/test_apps/security/secure_boot', efuse_reset_port=efuse_port)
dut_start_secure_app(dut)
dut.reset_efuses()
dut.secure_boot_burn_en_bit()
dut.secure_boot_burn_digest('test_rsa_3072_key.pem', 0, 0)
app_bin = os.path.join(dut.app.binary_path, 'secure_boot.bin')
with open(app_bin, 'rb') as f:
signed_app = f.read()
seeds = range(0, 384)
max_seed = max(seeds)
for seed in seeds:
print('Case %d / %d' % (seed, max_seed))
corrupt_app = corrupt_signature(signed_app, seed=seed)
dut.write_flash_data([(0x20000, BytesIO(corrupt_app))])
dut.expect('Signature Check Failed', timeout=2)
dut.expect('image valid, signature bad', timeout=2)
print('Testing invalid CRC...')
# Valid signature but invalid CRC
dut.reset_efuses()
dut.secure_boot_burn_en_bit()
dut.secure_boot_burn_digest('test_rsa_3072_key.pem', 0, 0)
corrupt_app = corrupt_signature(signed_app, corrupt_sig=False, corrupt_crc=True)
dut.write_flash_data([(0x20000, BytesIO(corrupt_app))])
dut.expect('Sig block 0 invalid: Stored CRC ends', timeout=2)
dut.expect('Secure boot signature verification failed', timeout=2)
dut.expect('No bootable app partitions in the partition table', timeout=2)
if __name__ == '__main__':
test_examples_security_secure_boot()
test_examples_security_secure_boot_key_combo()
test_examples_security_secure_boot_key_revoke()
test_examples_security_secure_boot_corrupt_bl_sig()
test_examples_security_secure_boot_corrupt_app_sig()