test/py: add TPMv2.x test suite

Add tests for the TPMv2.x commands.
These commands may run both on a physical TPM and with the sandbox
driver.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

test/py/tests/test_tpm2.py

+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2018, Bootlin
+# Author: Miquel Raynal <miquel.raynal@bootlin.com>
+
+import os.path
+import pytest
+import u_boot_utils
+import re
+import time
+
+"""
+Test the TPMv2.x related commands. You must have a working hardware setup in
+order to do these tests.
+
+Notes:
+* These tests will prove the password mechanism. The TPM chip must be cleared of
+any password.
+* Commands like pcr_setauthpolicy and pcr_resetauthpolicy are not implemented
+here because they would fail the tests in most cases (TPMs do not implement them
+and return an error).
+"""
+
+updates = 0
+
+def force_init(u_boot_console, force=False):
+    """When a test fails, U-Boot is reset. Because TPM stack must be initialized
+    after each reboot, we must ensure these lines are always executed before
+    trying any command or they will fail with no reason. Executing 'tpm init'
+    twice will spawn an error used to detect that the TPM was not reset and no
+    initialization code should be run.
+    """
+    output = u_boot_console.run_command('tpm init')
+    if force or not 'Error' in output:
+        u_boot_console.run_command('echo --- start of init ---')
+        u_boot_console.run_command('tpm startup TPM2_SU_CLEAR')
+        u_boot_console.run_command('tpm self_test full')
+        u_boot_console.run_command('tpm clear TPM2_RH_LOCKOUT')
+        output = u_boot_console.run_command('echo $?')
+        if not output.endswith('0'):
+            u_boot_console.run_command('tpm clear TPM2_RH_PLATFORM')
+        u_boot_console.run_command('echo --- end of init ---')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_init(u_boot_console):
+    """Init the software stack to use TPMv2 commands."""
+
+    u_boot_console.run_command('tpm init')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_startup(u_boot_console):
+    """Execute a TPM2_Startup command.
+
+    Initiate the TPM internal state machine.
+    """
+
+    u_boot_console.run_command('tpm startup TPM2_SU_CLEAR')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_self_test_full(u_boot_console):
+    """Execute a TPM2_SelfTest (full) command.
+
+    Ask the TPM to perform all self tests to also enable full capabilities.
+    """
+
+    u_boot_console.run_command('tpm self_test full')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_continue_self_test(u_boot_console):
+    """Execute a TPM2_SelfTest (continued) command.
+
+    Ask the TPM to finish its self tests (alternative to the full test) in order
+    to enter a fully operational state.
+    """
+
+    u_boot_console.run_command('tpm self_test continue')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_clear(u_boot_console):
+    """Execute a TPM2_Clear command.
+
+    Ask the TPM to reset entirely its internal state (including internal
+    configuration, passwords, counters and DAM parameters). This is half of the
+    TAKE_OWNERSHIP command from TPMv1.
+
+    Use the LOCKOUT hierarchy for this. The LOCKOUT/PLATFORM hierarchies must
+    not have a password set, otherwise this test will fail. ENDORSEMENT and
+    PLATFORM hierarchies are also available.
+    """
+
+    u_boot_console.run_command('tpm clear TPM2_RH_LOCKOUT')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+    u_boot_console.run_command('tpm clear TPM2_RH_PLATFORM')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_change_auth(u_boot_console):
+    """Execute a TPM2_HierarchyChangeAuth command.
+
+    Ask the TPM to change the owner, ie. set a new password: 'unicorn'
+
+    Use the LOCKOUT hierarchy for this. ENDORSEMENT and PLATFORM hierarchies are
+    also available.
+    """
+
+    force_init(u_boot_console)
+
+    u_boot_console.run_command('tpm change_auth TPM2_RH_LOCKOUT unicorn')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+    u_boot_console.run_command('tpm clear TPM2_RH_LOCKOUT unicorn')
+    output = u_boot_console.run_command('echo $?')
+    u_boot_console.run_command('tpm clear TPM2_RH_PLATFORM')
+    assert output.endswith('0')
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_get_capability(u_boot_console):
+    """Execute a TPM_GetCapability command.
+
+    Display one capability. In our test case, let's display the default DAM
+    lockout counter that should be 0 since the CLEAR:
+    - TPM_CAP_TPM_PROPERTIES = 0x6
+    - TPM_PT_LOCKOUT_COUNTER (1st parameter) = PTR_VAR + 14
+
+    There is no expected default values because it would depend on the chip
+    used. We can still save them in order to check they have changed later.
+    """
+
+    force_init(u_boot_console)
+    ram = u_boot_utils.find_ram_base(u_boot_console)
+
+    read_cap = u_boot_console.run_command('tpm get_capability 0x6 0x20e 0x200 1') #0x%x 1' % ram)
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+    assert 'Property 0x0000020e: 0x00000000' in read_cap
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_dam_parameters(u_boot_console):
+    """Execute a TPM2_DictionaryAttackParameters command.
+
+    Change Dictionary Attack Mitigation (DAM) parameters. Ask the TPM to change:
+    - Max number of failed authentication before lockout: 3
+    - Time before the failure counter is automatically decremented: 10 sec
+    - Time after a lockout failure before it can be attempted again: 0 sec
+
+    For an unknown reason, the DAM parameters must be changed before changing
+    the authentication, otherwise the lockout will be engaged after the first
+    failed authentication attempt.
+    """
+
+    force_init(u_boot_console)
+    ram = u_boot_utils.find_ram_base(u_boot_console)
+
+    # Set the DAM parameters to known values
+    u_boot_console.run_command('tpm dam_parameters 3 10 0')
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+    # Check the values have been saved
+    read_cap = u_boot_console.run_command('tpm get_capability 0x6 0x20f 0x%x 3' % ram)
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+    assert 'Property 0x0000020f: 0x00000003' in read_cap
+    assert 'Property 0x00000210: 0x0000000a' in read_cap
+    assert 'Property 0x00000211: 0x00000000' in read_cap
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_pcr_read(u_boot_console):
+    """Execute a TPM2_PCR_Read command.
+
+    Perform a PCR read of the 0th PCR. Must be zero.
+    """
+
+    force_init(u_boot_console)
+    ram = u_boot_utils.find_ram_base(u_boot_console) + 1024
+
+    read_pcr = u_boot_console.run_command('tpm pcr_read 0 0x%x' % ram)
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+    # Save the number of PCR updates
+    str = re.findall(r'\d+ known updates', read_pcr)[0]
+    global updates
+    updates = int(re.findall(r'\d+', str)[0])
+
+    # Check the output value
+    assert 'PCR #0 content' in read_pcr
+    assert '00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00' in read_pcr
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_pcr_extend(u_boot_console):
+    """Execute a TPM2_PCR_Extend command.
+
+    Perform a PCR extension with a known hash in memory (zeroed since the board
+    must have been rebooted).
+
+    No authentication mechanism is used here, not protecting against packet
+    replay, yet.
+    """
+
+    force_init(u_boot_console)
+    ram = u_boot_utils.find_ram_base(u_boot_console) + 1024
+
+    u_boot_console.run_command('tpm pcr_extend 0 0x%x' % ram)
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+
+    read_pcr = u_boot_console.run_command('tpm pcr_read 0 0x%x' % ram)
+    output = u_boot_console.run_command('echo $?')
+    assert output.endswith('0')
+    assert 'f5 a5 fd 42 d1 6a 20 30 27 98 ef 6e d3 09 97 9b' in read_pcr
+    assert '43 00 3d 23 20 d9 f0 e8 ea 98 31 a9 27 59 fb 4b' in read_pcr
+
+    str = re.findall(r'\d+ known updates', read_pcr)[0]
+    new_updates = int(re.findall(r'\d+', str)[0])
+    assert (updates + 1) == new_updates
+
+@pytest.mark.buildconfigspec('cmd_tpm_v2')
+def test_tpm2_cleanup(u_boot_console):
+    """Ensure the TPM is cleared from password or test related configuration."""
+
+    force_init(u_boot_console, True)