1# Copyright (c) 2016, 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 verification 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.run_and_log(cons, 'dtc %s %s%s -O dtb ' 54 '-o %s%s' % (dtc_args, datadir, dts, tmpdir, dtb)) 55 56 def run_bootm(sha_algo, 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 sha_algo: Either 'sha1' or 'sha256', to select the algorithm to 66 use. 67 """ 68 cons.cleanup_spawn() 69 cons.ensure_spawned() 70 cons.log.action('%s: Test Verified Boot Run: %s' % (sha_algo, test_type)) 71 output = cons.run_command_list( 72 ['sb load hostfs - 100 %stest.fit' % tmpdir, 73 'fdt addr 100', 74 'bootm 100']) 75 assert(expect_string in output) 76 77 def make_fit(its): 78 """Make a new FIT from the .its source file. 79 80 This runs 'mkimage -f' to create a new FIT. 81 82 Args: 83 its: Filename containing .its source. 84 """ 85 util.run_and_log(cons, [mkimage, '-D', dtc_args, '-f', 86 '%s%s' % (datadir, its), fit]) 87 88 def sign_fit(sha_algo): 89 """Sign the FIT 90 91 Signs the FIT and writes the signature into it. It also writes the 92 public key into the dtb. 93 94 Args: 95 sha_algo: Either 'sha1' or 'sha256', to select the algorithm to 96 use. 97 """ 98 cons.log.action('%s: Sign images' % sha_algo) 99 util.run_and_log(cons, [mkimage, '-F', '-k', tmpdir, '-K', dtb, 100 '-r', fit]) 101 102 def test_with_algo(sha_algo): 103 """Test verified boot with the given hash algorithm. 104 105 This is the main part of the test code. The same procedure is followed 106 for both hashing algorithms. 107 108 Args: 109 sha_algo: Either 'sha1' or 'sha256', to select the algorithm to 110 use. 111 """ 112 # Compile our device tree files for kernel and U-Boot. These are 113 # regenerated here since mkimage will modify them (by adding a 114 # public key) below. 115 dtc('sandbox-kernel.dts') 116 dtc('sandbox-u-boot.dts') 117 118 # Build the FIT, but don't sign anything yet 119 cons.log.action('%s: Test FIT with signed images' % sha_algo) 120 make_fit('sign-images-%s.its' % sha_algo) 121 run_bootm(sha_algo, 'unsigned images', 'dev-') 122 123 # Sign images with our dev keys 124 sign_fit(sha_algo) 125 run_bootm(sha_algo, 'signed images', 'dev+') 126 127 # Create a fresh .dtb without the public keys 128 dtc('sandbox-u-boot.dts') 129 130 cons.log.action('%s: Test FIT with signed configuration' % sha_algo) 131 make_fit('sign-configs-%s.its' % sha_algo) 132 run_bootm(sha_algo, 'unsigned config', '%s+ OK' % sha_algo) 133 134 # Sign images with our dev keys 135 sign_fit(sha_algo) 136 run_bootm(sha_algo, 'signed config', 'dev+') 137 138 cons.log.action('%s: Check signed config on the host' % sha_algo) 139 140 util.run_and_log(cons, [fit_check_sign, '-f', fit, '-k', tmpdir, 141 '-k', dtb]) 142 143 # Increment the first byte of the signature, which should cause failure 144 sig = util.run_and_log(cons, 'fdtget -t bx %s %s value' % 145 (fit, sig_node)) 146 byte_list = sig.split() 147 byte = int(byte_list[0], 16) 148 byte_list[0] = '%x' % (byte + 1) 149 sig = ' '.join(byte_list) 150 util.run_and_log(cons, 'fdtput -t bx %s %s value %s' % 151 (fit, sig_node, sig)) 152 153 run_bootm(sha_algo, 'Signed config with bad hash', 'Bad Data Hash') 154 155 cons.log.action('%s: Check bad config on the host' % sha_algo) 156 util.run_and_log_expect_exception(cons, [fit_check_sign, '-f', fit, 157 '-k', dtb], 1, 'Failed to verify required signature') 158 159 cons = u_boot_console 160 tmpdir = cons.config.result_dir + '/' 161 tmp = tmpdir + 'vboot.tmp' 162 datadir = cons.config.source_dir + '/test/py/tests/vboot/' 163 fit = '%stest.fit' % tmpdir 164 mkimage = cons.config.build_dir + '/tools/mkimage' 165 fit_check_sign = cons.config.build_dir + '/tools/fit_check_sign' 166 dtc_args = '-I dts -O dtb -i %s' % tmpdir 167 dtb = '%ssandbox-u-boot.dtb' % tmpdir 168 sig_node = '/configurations/conf@1/signature@1' 169 170 # Create an RSA key pair 171 public_exponent = 65537 172 util.run_and_log(cons, 'openssl genpkey -algorithm RSA -out %sdev.key ' 173 '-pkeyopt rsa_keygen_bits:2048 ' 174 '-pkeyopt rsa_keygen_pubexp:%d ' 175 '2>/dev/null' % (tmpdir, public_exponent)) 176 177 # Create a certificate containing the public key 178 util.run_and_log(cons, 'openssl req -batch -new -x509 -key %sdev.key -out ' 179 '%sdev.crt' % (tmpdir, tmpdir)) 180 181 # Create a number kernel image with zeroes 182 with open('%stest-kernel.bin' % tmpdir, 'w') as fd: 183 fd.write(5000 * chr(0)) 184 185 try: 186 # We need to use our own device tree file. Remember to restore it 187 # afterwards. 188 old_dtb = cons.config.dtb 189 cons.config.dtb = dtb 190 test_with_algo('sha1') 191 test_with_algo('sha256') 192 finally: 193 cons.config.dtb = old_dtb 194