1# Copyright (c) 2013, Google Inc. 2# 3# SPDX-License-Identifier: GPL-2.0+ 4# 5# U-Boot Verified Boot Test 6 7""" 8This tests verified boot in the following ways: 9 10For image verification: 11- Create FIT (unsigned) with mkimage 12- Check that verification shows that no keys are verified 13- Sign image 14- Check that verification shows that a key is now verified 15 16For configuration verification: 17- Corrupt signature and check for failure 18- Create FIT (with unsigned configuration) with mkimage 19- Check that image veriication works 20- Sign the FIT and mark the key as 'required' for verification 21- Check that image verification works 22- Corrupt the signature 23- Check that image verification no-longer works 24 25Tests run with both SHA1 and SHA256 hashing. 26""" 27 28import pytest 29import sys 30import u_boot_utils as util 31 32@pytest.mark.boardspec('sandbox') 33@pytest.mark.buildconfigspec('fit_signature') 34def test_vboot(u_boot_console): 35 """Test verified boot signing with mkimage and verification with 'bootm'. 36 37 This works using sandbox only as it needs to update the device tree used 38 by U-Boot to hold public keys from the signing process. 39 40 The SHA1 and SHA256 tests are combined into a single test since the 41 key-generation process is quite slow and we want to avoid doing it twice. 42 """ 43 def dtc(dts): 44 """Run the device-tree compiler to compile a .dts file 45 46 The output file will be the same as the input file but with a .dtb 47 extension. 48 49 Args: 50 dts: Device tree file to compile. 51 """ 52 dtb = dts.replace('.dts', '.dtb') 53 util.cmd(cons, 'dtc %s %s%s -O dtb ' 54 '-o %s%s' % (dtc_args, datadir, dts, tmpdir, dtb)) 55 56 def run_bootm(test_type, expect_string): 57 """Run a 'bootm' command U-Boot. 58 59 This always starts a fresh U-Boot instance since the device tree may 60 contain a new public key. 61 62 Args: 63 test_type: A string identifying the test type 64 expect_string: A string which is expected in the output 65 """ 66 cons.cleanup_spawn() 67 cons.ensure_spawned() 68 cons.log.action('%s: Test Verified Boot Run: %s' % (algo, test_type)) 69 output = cons.run_command_list( 70 ['sb load hostfs - 100 %stest.fit' % tmpdir, 71 'fdt addr 100', 72 'bootm 100']) 73 assert(expect_string in output) 74 75 def make_fit(its): 76 """Make a new FIT from the .its source file 77 78 This runs 'mkimage -f' to create a new FIT. 79 80 Args: 81 its: Filename containing .its source 82 """ 83 util.run_and_log(cons, [mkimage, '-D', dtc_args, '-f', 84 '%s%s' % (datadir, its), fit]) 85 86 def sign_fit(): 87 """Sign the FIT 88 89 Signs the FIT and writes the signature into it. It also writes the 90 public key into the dtb. 91 """ 92 cons.log.action('%s: Sign images' % algo) 93 util.run_and_log(cons, [mkimage, '-F', '-k', tmpdir, '-K', dtb, 94 '-r', fit]) 95 96 def test_with_algo(sha): 97 """Test verified boot with the given hash algorithm 98 99 This is the main part of the test code. The same procedure is followed 100 for both hashing algorithms. 101 102 Args: 103 sha: Either 'sha1' or 'sha256', to select the algorithm to use 104 """ 105 global algo 106 107 algo = sha 108 109 # Compile our device tree files for kernel and U-Boot 110 dtc('sandbox-kernel.dts') 111 dtc('sandbox-u-boot.dts') 112 113 # Build the FIT, but don't sign anything yet 114 cons.log.action('%s: Test FIT with signed images' % algo) 115 make_fit('sign-images-%s.its' % algo) 116 run_bootm('unsigned images', 'dev-') 117 118 # Sign images with our dev keys 119 sign_fit() 120 run_bootm('signed images', 'dev+') 121 122 # Create a fresh .dtb without the public keys 123 dtc('sandbox-u-boot.dts') 124 125 cons.log.action('%s: Test FIT with signed configuration' % algo) 126 make_fit('sign-configs-%s.its' % algo) 127 run_bootm('unsigned config', '%s+ OK' % algo) 128 129 # Sign images with our dev keys 130 sign_fit() 131 run_bootm('signed config', 'dev+') 132 133 cons.log.action('%s: Check signed config on the host' % algo) 134 135 util.run_and_log(cons, [fit_check_sign, '-f', fit, '-k', tmpdir, 136 '-k', dtb]) 137 138 # Increment the first byte of the signature, which should cause failure 139 sig = util.cmd(cons, 'fdtget -t bx %s %s value' % (fit, sig_node)) 140 byte_list = sig.split() 141 byte = int(byte_list[0], 16) 142 byte_list = ['%x' % (byte + 1)] + byte_list[1:] 143 sig = ' '.join(byte_list) 144 util.cmd(cons, 'fdtput -t bx %s %s value %s' % (fit, sig_node, sig)) 145 146 run_bootm('Signed config with bad hash', 'Bad Data Hash') 147 148 cons.log.action('%s: Check bad config on the host' % algo) 149 util.run_and_log_expect_exception(cons, [fit_check_sign, '-f', fit, 150 '-k', dtb], 1, 'Failed to verify required signature') 151 152 cons = u_boot_console 153 tmpdir = cons.config.result_dir + '/' 154 tmp = tmpdir + 'vboot.tmp' 155 datadir = cons.config.source_dir + '/test/py/tests/vboot/' 156 fit = '%stest.fit' % tmpdir 157 mkimage = cons.config.build_dir + '/tools/mkimage' 158 fit_check_sign = cons.config.build_dir + '/tools/fit_check_sign' 159 dtc_args = '-I dts -O dtb -i %s' % tmpdir 160 dtb = '%ssandbox-u-boot.dtb' % tmpdir 161 sig_node = '/configurations/conf@1/signature@1' 162 163 # Create an RSA key pair 164 public_exponent = 65537 165 util.cmd(cons, 'openssl genpkey -algorithm RSA -out %sdev.key ' 166 '-pkeyopt rsa_keygen_bits:2048 ' 167 '-pkeyopt rsa_keygen_pubexp:%d ' 168 '2>/dev/null' % (tmpdir, public_exponent)) 169 170 # Create a certificate containing the public key 171 util.cmd(cons, 'openssl req -batch -new -x509 -key %sdev.key -out ' 172 '%sdev.crt' % (tmpdir, tmpdir)) 173 174 # Create a number kernel image with zeroes 175 with open('%stest-kernel.bin' % tmpdir, 'w') as fd: 176 fd.write(5000 * chr(0)) 177 178 try: 179 # We need to use our own device tree file. Remember to restore it 180 # afterwards. 181 old_dtb = cons.config.dtb 182 cons.config.dtb = dtb 183 test_with_algo('sha1') 184 test_with_algo('sha256') 185 finally: 186 cons.config.dtb = old_dtb 187