Commit 0d060f23 authored by Stefan Berger's avatar Stefan Berger Committed by Jarkko Sakkinen
Browse files

selftests: tpm2: Determine available PCR bank 



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: default avatarStefan Berger <stefanb@linux.ibm.com>
Tested-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: default avatarJarkko Sakkinen <jarkko@kernel.org>
parent ea4424be

tools/testing/selftests/tpm2/tpm2.py

+31 −0
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/tpm2/tpm2_tests.py

+21 −8
Original line number Diff line number Diff line
@@ -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)