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Message-Id: <20211128041052.1395504-2-stefanb@linux.vnet.ibm.com>
Date: Sat, 27 Nov 2021 23:10:51 -0500
From: Stefan Berger <stefanb@...ux.vnet.ibm.com>
To: jarkko@...nel.org, linux-integrity@...r.kernel.org
Cc: peterhuewe@....de, linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org, skhan@...uxfoundation.org,
Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH v4 1/2] selftests: tpm2: Determine available PCR bank
From: Stefan Berger <stefanb@...ux.ibm.com>
Determine an available PCR bank to be used by a test case by querying the
capability TPM2_GET_CAP. The TPM2 returns TPML_PCR_SELECTIONS that
contains an array of TPMS_PCR_SELECTIONs indicating available PCR banks
and the bitmasks that show which PCRs are enabled in each bank. Collect
the data in a dictionary. From the dictionary determine the PCR bank that
has the PCRs enabled that the test needs. This avoids test failures with
TPM2's that either to not have a SHA-1 bank or whose SHA-1 bank is
disabled.
Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
---
tools/testing/selftests/tpm2/tpm2.py | 31 ++++++++++++++++++++++
tools/testing/selftests/tpm2/tpm2_tests.py | 29 ++++++++++++++------
2 files changed, 52 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/tpm2/tpm2.py b/tools/testing/selftests/tpm2/tpm2.py
index f34486cd7342..057a4f49c79d 100644
--- a/tools/testing/selftests/tpm2/tpm2.py
+++ b/tools/testing/selftests/tpm2/tpm2.py
@@ -56,6 +56,7 @@ TSS2_RESMGR_TPM_RC_LAYER = (11 << TSS2_RC_LAYER_SHIFT)
TPM2_CAP_HANDLES = 0x00000001
TPM2_CAP_COMMANDS = 0x00000002
+TPM2_CAP_PCRS = 0x00000005
TPM2_CAP_TPM_PROPERTIES = 0x00000006
TPM2_PT_FIXED = 0x100
@@ -712,3 +713,33 @@ class Client:
pt += 1
return handles
+
+ def get_cap_pcrs(self):
+ pcr_banks = {}
+
+ fmt = '>HII III'
+
+ cmd = struct.pack(fmt,
+ TPM2_ST_NO_SESSIONS,
+ struct.calcsize(fmt),
+ TPM2_CC_GET_CAPABILITY,
+ TPM2_CAP_PCRS, 0, 1)
+ rsp = self.send_cmd(cmd)[10:]
+ _, _, cnt = struct.unpack('>BII', rsp[:9])
+ rsp = rsp[9:]
+
+ # items are TPMS_PCR_SELECTION's
+ for i in range(0, cnt):
+ hash, sizeOfSelect = struct.unpack('>HB', rsp[:3])
+ rsp = rsp[3:]
+
+ pcrSelect = 0
+ if sizeOfSelect > 0:
+ pcrSelect, = struct.unpack('%ds' % sizeOfSelect,
+ rsp[:sizeOfSelect])
+ rsp = rsp[sizeOfSelect:]
+ pcrSelect = int.from_bytes(pcrSelect, byteorder='big')
+
+ pcr_banks[hash] = pcrSelect
+
+ return pcr_banks
diff --git a/tools/testing/selftests/tpm2/tpm2_tests.py b/tools/testing/selftests/tpm2/tpm2_tests.py
index 9d764306887b..e63a37819978 100644
--- a/tools/testing/selftests/tpm2/tpm2_tests.py
+++ b/tools/testing/selftests/tpm2/tpm2_tests.py
@@ -27,7 +27,17 @@ class SmokeTest(unittest.TestCase):
result = self.client.unseal(self.root_key, blob, auth, None)
self.assertEqual(data, result)
+ def determine_bank_alg(self, mask):
+ pcr_banks = self.client.get_cap_pcrs()
+ for bank_alg, pcrSelection in pcr_banks.items():
+ if pcrSelection & mask == mask:
+ return bank_alg
+ return None
+
def test_seal_with_policy(self):
+ bank_alg = self.determine_bank_alg(1 << 16)
+ self.assertIsNotNone(bank_alg)
+
handle = self.client.start_auth_session(tpm2.TPM2_SE_TRIAL)
data = ('X' * 64).encode()
@@ -35,7 +45,7 @@ class SmokeTest(unittest.TestCase):
pcrs = [16]
try:
- self.client.policy_pcr(handle, pcrs)
+ self.client.policy_pcr(handle, pcrs, bank_alg=bank_alg)
self.client.policy_password(handle)
policy_dig = self.client.get_policy_digest(handle)
@@ -47,7 +57,7 @@ class SmokeTest(unittest.TestCase):
handle = self.client.start_auth_session(tpm2.TPM2_SE_POLICY)
try:
- self.client.policy_pcr(handle, pcrs)
+ self.client.policy_pcr(handle, pcrs, bank_alg=bank_alg)
self.client.policy_password(handle)
result = self.client.unseal(self.root_key, blob, auth, handle)
@@ -72,6 +82,9 @@ class SmokeTest(unittest.TestCase):
self.assertEqual(rc, tpm2.TPM2_RC_AUTH_FAIL)
def test_unseal_with_wrong_policy(self):
+ bank_alg = self.determine_bank_alg(1 << 16 | 1 << 1)
+ self.assertIsNotNone(bank_alg)
+
handle = self.client.start_auth_session(tpm2.TPM2_SE_TRIAL)
data = ('X' * 64).encode()
@@ -79,7 +92,7 @@ class SmokeTest(unittest.TestCase):
pcrs = [16]
try:
- self.client.policy_pcr(handle, pcrs)
+ self.client.policy_pcr(handle, pcrs, bank_alg=bank_alg)
self.client.policy_password(handle)
policy_dig = self.client.get_policy_digest(handle)
@@ -91,13 +104,13 @@ class SmokeTest(unittest.TestCase):
# Extend first a PCR that is not part of the policy and try to unseal.
# This should succeed.
- ds = tpm2.get_digest_size(tpm2.TPM2_ALG_SHA1)
- self.client.extend_pcr(1, ('X' * ds).encode())
+ ds = tpm2.get_digest_size(bank_alg)
+ self.client.extend_pcr(1, ('X' * ds).encode(), bank_alg=bank_alg)
handle = self.client.start_auth_session(tpm2.TPM2_SE_POLICY)
try:
- self.client.policy_pcr(handle, pcrs)
+ self.client.policy_pcr(handle, pcrs, bank_alg=bank_alg)
self.client.policy_password(handle)
result = self.client.unseal(self.root_key, blob, auth, handle)
@@ -109,14 +122,14 @@ class SmokeTest(unittest.TestCase):
# Then, extend a PCR that is part of the policy and try to unseal.
# This should fail.
- self.client.extend_pcr(16, ('X' * ds).encode())
+ self.client.extend_pcr(16, ('X' * ds).encode(), bank_alg=bank_alg)
handle = self.client.start_auth_session(tpm2.TPM2_SE_POLICY)
rc = 0
try:
- self.client.policy_pcr(handle, pcrs)
+ self.client.policy_pcr(handle, pcrs, bank_alg=bank_alg)
self.client.policy_password(handle)
result = self.client.unseal(self.root_key, blob, auth, handle)
--
2.31.1
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