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1# SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2
3import hashlib
4import os
5import socket
6import struct
7import sys
8import unittest
9import fcntl
10import select
11
12TPM2_ST_NO_SESSIONS = 0x8001
13TPM2_ST_SESSIONS = 0x8002
14
15TPM2_CC_FIRST = 0x01FF
16
17TPM2_CC_CREATE_PRIMARY = 0x0131
18TPM2_CC_DICTIONARY_ATTACK_LOCK_RESET = 0x0139
19TPM2_CC_CREATE = 0x0153
20TPM2_CC_LOAD = 0x0157
21TPM2_CC_UNSEAL = 0x015E
22TPM2_CC_FLUSH_CONTEXT = 0x0165
23TPM2_CC_START_AUTH_SESSION = 0x0176
24TPM2_CC_GET_CAPABILITY	= 0x017A
25TPM2_CC_GET_RANDOM = 0x017B
26TPM2_CC_PCR_READ = 0x017E
27TPM2_CC_POLICY_PCR = 0x017F
28TPM2_CC_PCR_EXTEND = 0x0182
29TPM2_CC_POLICY_PASSWORD = 0x018C
30TPM2_CC_POLICY_GET_DIGEST = 0x0189
31
32TPM2_SE_POLICY = 0x01
33TPM2_SE_TRIAL = 0x03
34
35TPM2_ALG_RSA = 0x0001
36TPM2_ALG_SHA1 = 0x0004
37TPM2_ALG_AES = 0x0006
38TPM2_ALG_KEYEDHASH = 0x0008
39TPM2_ALG_SHA256 = 0x000B
40TPM2_ALG_NULL = 0x0010
41TPM2_ALG_CBC = 0x0042
42TPM2_ALG_CFB = 0x0043
43
44TPM2_RH_OWNER = 0x40000001
45TPM2_RH_NULL = 0x40000007
46TPM2_RH_LOCKOUT = 0x4000000A
47TPM2_RS_PW = 0x40000009
48
49TPM2_RC_SIZE            = 0x01D5
50TPM2_RC_AUTH_FAIL       = 0x098E
51TPM2_RC_POLICY_FAIL     = 0x099D
52TPM2_RC_COMMAND_CODE    = 0x0143
53
54TSS2_RC_LAYER_SHIFT = 16
55TSS2_RESMGR_TPM_RC_LAYER = (11 << TSS2_RC_LAYER_SHIFT)
56
57TPM2_CAP_HANDLES = 0x00000001
58TPM2_CAP_COMMANDS = 0x00000002
59TPM2_CAP_TPM_PROPERTIES = 0x00000006
60
61TPM2_PT_FIXED = 0x100
62TPM2_PT_TOTAL_COMMANDS = TPM2_PT_FIXED + 41
63
64HR_SHIFT = 24
65HR_LOADED_SESSION = 0x02000000
66HR_TRANSIENT = 0x80000000
67
68SHA1_DIGEST_SIZE = 20
69SHA256_DIGEST_SIZE = 32
70
71TPM2_VER0_ERRORS = {
72    0x000: "TPM_RC_SUCCESS",
73    0x030: "TPM_RC_BAD_TAG",
74}
75
76TPM2_VER1_ERRORS = {
77    0x000: "TPM_RC_FAILURE",
78    0x001: "TPM_RC_FAILURE",
79    0x003: "TPM_RC_SEQUENCE",
80    0x00B: "TPM_RC_PRIVATE",
81    0x019: "TPM_RC_HMAC",
82    0x020: "TPM_RC_DISABLED",
83    0x021: "TPM_RC_EXCLUSIVE",
84    0x024: "TPM_RC_AUTH_TYPE",
85    0x025: "TPM_RC_AUTH_MISSING",
86    0x026: "TPM_RC_POLICY",
87    0x027: "TPM_RC_PCR",
88    0x028: "TPM_RC_PCR_CHANGED",
89    0x02D: "TPM_RC_UPGRADE",
90    0x02E: "TPM_RC_TOO_MANY_CONTEXTS",
91    0x02F: "TPM_RC_AUTH_UNAVAILABLE",
92    0x030: "TPM_RC_REBOOT",
93    0x031: "TPM_RC_UNBALANCED",
94    0x042: "TPM_RC_COMMAND_SIZE",
95    0x043: "TPM_RC_COMMAND_CODE",
96    0x044: "TPM_RC_AUTHSIZE",
97    0x045: "TPM_RC_AUTH_CONTEXT",
98    0x046: "TPM_RC_NV_RANGE",
99    0x047: "TPM_RC_NV_SIZE",
100    0x048: "TPM_RC_NV_LOCKED",
101    0x049: "TPM_RC_NV_AUTHORIZATION",
102    0x04A: "TPM_RC_NV_UNINITIALIZED",
103    0x04B: "TPM_RC_NV_SPACE",
104    0x04C: "TPM_RC_NV_DEFINED",
105    0x050: "TPM_RC_BAD_CONTEXT",
106    0x051: "TPM_RC_CPHASH",
107    0x052: "TPM_RC_PARENT",
108    0x053: "TPM_RC_NEEDS_TEST",
109    0x054: "TPM_RC_NO_RESULT",
110    0x055: "TPM_RC_SENSITIVE",
111    0x07F: "RC_MAX_FM0",
112}
113
114TPM2_FMT1_ERRORS = {
115    0x001: "TPM_RC_ASYMMETRIC",
116    0x002: "TPM_RC_ATTRIBUTES",
117    0x003: "TPM_RC_HASH",
118    0x004: "TPM_RC_VALUE",
119    0x005: "TPM_RC_HIERARCHY",
120    0x007: "TPM_RC_KEY_SIZE",
121    0x008: "TPM_RC_MGF",
122    0x009: "TPM_RC_MODE",
123    0x00A: "TPM_RC_TYPE",
124    0x00B: "TPM_RC_HANDLE",
125    0x00C: "TPM_RC_KDF",
126    0x00D: "TPM_RC_RANGE",
127    0x00E: "TPM_RC_AUTH_FAIL",
128    0x00F: "TPM_RC_NONCE",
129    0x010: "TPM_RC_PP",
130    0x012: "TPM_RC_SCHEME",
131    0x015: "TPM_RC_SIZE",
132    0x016: "TPM_RC_SYMMETRIC",
133    0x017: "TPM_RC_TAG",
134    0x018: "TPM_RC_SELECTOR",
135    0x01A: "TPM_RC_INSUFFICIENT",
136    0x01B: "TPM_RC_SIGNATURE",
137    0x01C: "TPM_RC_KEY",
138    0x01D: "TPM_RC_POLICY_FAIL",
139    0x01F: "TPM_RC_INTEGRITY",
140    0x020: "TPM_RC_TICKET",
141    0x021: "TPM_RC_RESERVED_BITS",
142    0x022: "TPM_RC_BAD_AUTH",
143    0x023: "TPM_RC_EXPIRED",
144    0x024: "TPM_RC_POLICY_CC",
145    0x025: "TPM_RC_BINDING",
146    0x026: "TPM_RC_CURVE",
147    0x027: "TPM_RC_ECC_POINT",
148}
149
150TPM2_WARN_ERRORS = {
151    0x001: "TPM_RC_CONTEXT_GAP",
152    0x002: "TPM_RC_OBJECT_MEMORY",
153    0x003: "TPM_RC_SESSION_MEMORY",
154    0x004: "TPM_RC_MEMORY",
155    0x005: "TPM_RC_SESSION_HANDLES",
156    0x006: "TPM_RC_OBJECT_HANDLES",
157    0x007: "TPM_RC_LOCALITY",
158    0x008: "TPM_RC_YIELDED",
159    0x009: "TPM_RC_CANCELED",
160    0x00A: "TPM_RC_TESTING",
161    0x010: "TPM_RC_REFERENCE_H0",
162    0x011: "TPM_RC_REFERENCE_H1",
163    0x012: "TPM_RC_REFERENCE_H2",
164    0x013: "TPM_RC_REFERENCE_H3",
165    0x014: "TPM_RC_REFERENCE_H4",
166    0x015: "TPM_RC_REFERENCE_H5",
167    0x016: "TPM_RC_REFERENCE_H6",
168    0x018: "TPM_RC_REFERENCE_S0",
169    0x019: "TPM_RC_REFERENCE_S1",
170    0x01A: "TPM_RC_REFERENCE_S2",
171    0x01B: "TPM_RC_REFERENCE_S3",
172    0x01C: "TPM_RC_REFERENCE_S4",
173    0x01D: "TPM_RC_REFERENCE_S5",
174    0x01E: "TPM_RC_REFERENCE_S6",
175    0x020: "TPM_RC_NV_RATE",
176    0x021: "TPM_RC_LOCKOUT",
177    0x022: "TPM_RC_RETRY",
178    0x023: "TPM_RC_NV_UNAVAILABLE",
179    0x7F: "TPM_RC_NOT_USED",
180}
181
182RC_VER1 = 0x100
183RC_FMT1 = 0x080
184RC_WARN = 0x900
185
186ALG_DIGEST_SIZE_MAP = {
187    TPM2_ALG_SHA1: SHA1_DIGEST_SIZE,
188    TPM2_ALG_SHA256: SHA256_DIGEST_SIZE,
189}
190
191ALG_HASH_FUNCTION_MAP = {
192    TPM2_ALG_SHA1: hashlib.sha1,
193    TPM2_ALG_SHA256: hashlib.sha256
194}
195
196NAME_ALG_MAP = {
197    "sha1": TPM2_ALG_SHA1,
198    "sha256": TPM2_ALG_SHA256,
199}
200
201
202class UnknownAlgorithmIdError(Exception):
203    def __init__(self, alg):
204        self.alg = alg
205
206    def __str__(self):
207        return '0x%0x' % (alg)
208
209
210class UnknownAlgorithmNameError(Exception):
211    def __init__(self, name):
212        self.name = name
213
214    def __str__(self):
215        return name
216
217
218class UnknownPCRBankError(Exception):
219    def __init__(self, alg):
220        self.alg = alg
221
222    def __str__(self):
223        return '0x%0x' % (alg)
224
225
226class ProtocolError(Exception):
227    def __init__(self, cc, rc):
228        self.cc = cc
229        self.rc = rc
230
231        if (rc & RC_FMT1) == RC_FMT1:
232            self.name = TPM2_FMT1_ERRORS.get(rc & 0x3f, "TPM_RC_UNKNOWN")
233        elif (rc & RC_WARN) == RC_WARN:
234            self.name = TPM2_WARN_ERRORS.get(rc & 0x7f, "TPM_RC_UNKNOWN")
235        elif (rc & RC_VER1) == RC_VER1:
236            self.name = TPM2_VER1_ERRORS.get(rc & 0x7f, "TPM_RC_UNKNOWN")
237        else:
238            self.name = TPM2_VER0_ERRORS.get(rc & 0x7f, "TPM_RC_UNKNOWN")
239
240    def __str__(self):
241        if self.cc:
242            return '%s: cc=0x%08x, rc=0x%08x' % (self.name, self.cc, self.rc)
243        else:
244            return '%s: rc=0x%08x' % (self.name, self.rc)
245
246
247class AuthCommand(object):
248    """TPMS_AUTH_COMMAND"""
249
250    def __init__(self, session_handle=TPM2_RS_PW, nonce=bytes(),
251                 session_attributes=0, hmac=bytes()):
252        self.session_handle = session_handle
253        self.nonce = nonce
254        self.session_attributes = session_attributes
255        self.hmac = hmac
256
257    def __bytes__(self):
258        fmt = '>I H%us B H%us' % (len(self.nonce), len(self.hmac))
259        return struct.pack(fmt, self.session_handle, len(self.nonce),
260                           self.nonce, self.session_attributes, len(self.hmac),
261                           self.hmac)
262
263    def __len__(self):
264        fmt = '>I H%us B H%us' % (len(self.nonce), len(self.hmac))
265        return struct.calcsize(fmt)
266
267
268class SensitiveCreate(object):
269    """TPMS_SENSITIVE_CREATE"""
270
271    def __init__(self, user_auth=bytes(), data=bytes()):
272        self.user_auth = user_auth
273        self.data = data
274
275    def __bytes__(self):
276        fmt = '>H%us H%us' % (len(self.user_auth), len(self.data))
277        return struct.pack(fmt, len(self.user_auth), self.user_auth,
278                           len(self.data), self.data)
279
280    def __len__(self):
281        fmt = '>H%us H%us' % (len(self.user_auth), len(self.data))
282        return struct.calcsize(fmt)
283
284
285class Public(object):
286    """TPMT_PUBLIC"""
287
288    FIXED_TPM = (1 << 1)
289    FIXED_PARENT = (1 << 4)
290    SENSITIVE_DATA_ORIGIN = (1 << 5)
291    USER_WITH_AUTH = (1 << 6)
292    RESTRICTED = (1 << 16)
293    DECRYPT = (1 << 17)
294
295    def __fmt(self):
296        return '>HHIH%us%usH%us' % \
297            (len(self.auth_policy), len(self.parameters), len(self.unique))
298
299    def __init__(self, object_type, name_alg, object_attributes,
300                 auth_policy=bytes(), parameters=bytes(),
301                 unique=bytes()):
302        self.object_type = object_type
303        self.name_alg = name_alg
304        self.object_attributes = object_attributes
305        self.auth_policy = auth_policy
306        self.parameters = parameters
307        self.unique = unique
308
309    def __bytes__(self):
310        return struct.pack(self.__fmt(),
311                           self.object_type,
312                           self.name_alg,
313                           self.object_attributes,
314                           len(self.auth_policy),
315                           self.auth_policy,
316                           self.parameters,
317                           len(self.unique),
318                           self.unique)
319
320    def __len__(self):
321        return struct.calcsize(self.__fmt())
322
323
324def get_digest_size(alg):
325    ds = ALG_DIGEST_SIZE_MAP.get(alg)
326    if not ds:
327        raise UnknownAlgorithmIdError(alg)
328    return ds
329
330
331def get_hash_function(alg):
332    f = ALG_HASH_FUNCTION_MAP.get(alg)
333    if not f:
334        raise UnknownAlgorithmIdError(alg)
335    return f
336
337
338def get_algorithm(name):
339    alg = NAME_ALG_MAP.get(name)
340    if not alg:
341        raise UnknownAlgorithmNameError(name)
342    return alg
343
344
345def hex_dump(d):
346    d = [format(ord(x), '02x') for x in d]
347    d = [d[i: i + 16] for i in range(0, len(d), 16)]
348    d = [' '.join(x) for x in d]
349    d = os.linesep.join(d)
350
351    return d
352
353class Client:
354    FLAG_DEBUG = 0x01
355    FLAG_SPACE = 0x02
356    FLAG_NONBLOCK = 0x04
357    TPM_IOC_NEW_SPACE = 0xa200
358
359    def __init__(self, flags = 0):
360        self.flags = flags
361
362        if (self.flags & Client.FLAG_SPACE) == 0:
363            self.tpm = open('/dev/tpm0', 'r+b', buffering=0)
364        else:
365            self.tpm = open('/dev/tpmrm0', 'r+b', buffering=0)
366
367        if (self.flags & Client.FLAG_NONBLOCK):
368            flags = fcntl.fcntl(self.tpm, fcntl.F_GETFL)
369            flags |= os.O_NONBLOCK
370            fcntl.fcntl(self.tpm, fcntl.F_SETFL, flags)
371            self.tpm_poll = select.poll()
372
373    def __del__(self):
374        if self.tpm:
375            self.tpm.close()
376
377    def close(self):
378        self.tpm.close()
379
380    def send_cmd(self, cmd):
381        self.tpm.write(cmd)
382
383        if (self.flags & Client.FLAG_NONBLOCK):
384            self.tpm_poll.register(self.tpm, select.POLLIN)
385            self.tpm_poll.poll(10000)
386
387        rsp = self.tpm.read()
388
389        if (self.flags & Client.FLAG_NONBLOCK):
390            self.tpm_poll.unregister(self.tpm)
391
392        if (self.flags & Client.FLAG_DEBUG) != 0:
393            sys.stderr.write('cmd' + os.linesep)
394            sys.stderr.write(hex_dump(cmd) + os.linesep)
395            sys.stderr.write('rsp' + os.linesep)
396            sys.stderr.write(hex_dump(rsp) + os.linesep)
397
398        rc = struct.unpack('>I', rsp[6:10])[0]
399        if rc != 0:
400            cc = struct.unpack('>I', cmd[6:10])[0]
401            raise ProtocolError(cc, rc)
402
403        return rsp
404
405    def read_pcr(self, i, bank_alg = TPM2_ALG_SHA1):
406        pcrsel_len = max((i >> 3) + 1, 3)
407        pcrsel = [0] * pcrsel_len
408        pcrsel[i >> 3] = 1 << (i & 7)
409        pcrsel = ''.join(map(chr, pcrsel)).encode()
410
411        fmt = '>HII IHB%us' % (pcrsel_len)
412        cmd = struct.pack(fmt,
413                          TPM2_ST_NO_SESSIONS,
414                          struct.calcsize(fmt),
415                          TPM2_CC_PCR_READ,
416                          1,
417                          bank_alg,
418                          pcrsel_len, pcrsel)
419
420        rsp = self.send_cmd(cmd)
421
422        pcr_update_cnt, pcr_select_cnt = struct.unpack('>II', rsp[10:18])
423        assert pcr_select_cnt == 1
424        rsp = rsp[18:]
425
426        alg2, pcrsel_len2 = struct.unpack('>HB', rsp[:3])
427        assert bank_alg == alg2 and pcrsel_len == pcrsel_len2
428        rsp = rsp[3 + pcrsel_len:]
429
430        digest_cnt = struct.unpack('>I', rsp[:4])[0]
431        if digest_cnt == 0:
432            return None
433        rsp = rsp[6:]
434
435        return rsp
436
437    def extend_pcr(self, i, dig, bank_alg = TPM2_ALG_SHA1):
438        ds = get_digest_size(bank_alg)
439        assert(ds == len(dig))
440
441        auth_cmd = AuthCommand()
442
443        fmt = '>HII I I%us IH%us' % (len(auth_cmd), ds)
444        cmd = struct.pack(
445            fmt,
446            TPM2_ST_SESSIONS,
447            struct.calcsize(fmt),
448            TPM2_CC_PCR_EXTEND,
449            i,
450            len(auth_cmd),
451            bytes(auth_cmd),
452            1, bank_alg, dig)
453
454        self.send_cmd(cmd)
455
456    def start_auth_session(self, session_type, name_alg = TPM2_ALG_SHA1):
457        fmt = '>HII IIH16sHBHH'
458        cmd = struct.pack(fmt,
459                          TPM2_ST_NO_SESSIONS,
460                          struct.calcsize(fmt),
461                          TPM2_CC_START_AUTH_SESSION,
462                          TPM2_RH_NULL,
463                          TPM2_RH_NULL,
464                          16,
465                          ('\0' * 16).encode(),
466                          0,
467                          session_type,
468                          TPM2_ALG_NULL,
469                          name_alg)
470
471        return struct.unpack('>I', self.send_cmd(cmd)[10:14])[0]
472
473    def __calc_pcr_digest(self, pcrs, bank_alg = TPM2_ALG_SHA1,
474                          digest_alg = TPM2_ALG_SHA1):
475        x = []
476        f = get_hash_function(digest_alg)
477
478        for i in pcrs:
479            pcr = self.read_pcr(i, bank_alg)
480            if pcr is None:
481                return None
482            x += pcr
483
484        return f(bytearray(x)).digest()
485
486    def policy_pcr(self, handle, pcrs, bank_alg = TPM2_ALG_SHA1,
487                   name_alg = TPM2_ALG_SHA1):
488        ds = get_digest_size(name_alg)
489        dig = self.__calc_pcr_digest(pcrs, bank_alg, name_alg)
490        if not dig:
491            raise UnknownPCRBankError(bank_alg)
492
493        pcrsel_len = max((max(pcrs) >> 3) + 1, 3)
494        pcrsel = [0] * pcrsel_len
495        for i in pcrs:
496            pcrsel[i >> 3] |= 1 << (i & 7)
497        pcrsel = ''.join(map(chr, pcrsel)).encode()
498
499        fmt = '>HII IH%usIHB3s' % ds
500        cmd = struct.pack(fmt,
501                          TPM2_ST_NO_SESSIONS,
502                          struct.calcsize(fmt),
503                          TPM2_CC_POLICY_PCR,
504                          handle,
505                          len(dig),
506                          bytes(dig),
507                          1,
508                          bank_alg,
509                          pcrsel_len, pcrsel)
510
511        self.send_cmd(cmd)
512
513    def policy_password(self, handle):
514        fmt = '>HII I'
515        cmd = struct.pack(fmt,
516                          TPM2_ST_NO_SESSIONS,
517                          struct.calcsize(fmt),
518                          TPM2_CC_POLICY_PASSWORD,
519                          handle)
520
521        self.send_cmd(cmd)
522
523    def get_policy_digest(self, handle):
524        fmt = '>HII I'
525        cmd = struct.pack(fmt,
526                          TPM2_ST_NO_SESSIONS,
527                          struct.calcsize(fmt),
528                          TPM2_CC_POLICY_GET_DIGEST,
529                          handle)
530
531        return self.send_cmd(cmd)[12:]
532
533    def flush_context(self, handle):
534        fmt = '>HIII'
535        cmd = struct.pack(fmt,
536                          TPM2_ST_NO_SESSIONS,
537                          struct.calcsize(fmt),
538                          TPM2_CC_FLUSH_CONTEXT,
539                          handle)
540
541        self.send_cmd(cmd)
542
543    def create_root_key(self, auth_value = bytes()):
544        attributes = \
545            Public.FIXED_TPM | \
546            Public.FIXED_PARENT | \
547            Public.SENSITIVE_DATA_ORIGIN | \
548            Public.USER_WITH_AUTH | \
549            Public.RESTRICTED | \
550            Public.DECRYPT
551
552        auth_cmd = AuthCommand()
553        sensitive = SensitiveCreate(user_auth=auth_value)
554
555        public_parms = struct.pack(
556            '>HHHHHI',
557            TPM2_ALG_AES,
558            128,
559            TPM2_ALG_CFB,
560            TPM2_ALG_NULL,
561            2048,
562            0)
563
564        public = Public(
565            object_type=TPM2_ALG_RSA,
566            name_alg=TPM2_ALG_SHA1,
567            object_attributes=attributes,
568            parameters=public_parms)
569
570        fmt = '>HIII I%us H%us H%us HI' % \
571            (len(auth_cmd), len(sensitive), len(public))
572        cmd = struct.pack(
573            fmt,
574            TPM2_ST_SESSIONS,
575            struct.calcsize(fmt),
576            TPM2_CC_CREATE_PRIMARY,
577            TPM2_RH_OWNER,
578            len(auth_cmd),
579            bytes(auth_cmd),
580            len(sensitive),
581            bytes(sensitive),
582            len(public),
583            bytes(public),
584            0, 0)
585
586        return struct.unpack('>I', self.send_cmd(cmd)[10:14])[0]
587
588    def seal(self, parent_key, data, auth_value, policy_dig,
589             name_alg = TPM2_ALG_SHA1):
590        ds = get_digest_size(name_alg)
591        assert(not policy_dig or ds == len(policy_dig))
592
593        attributes = 0
594        if not policy_dig:
595            attributes |= Public.USER_WITH_AUTH
596            policy_dig = bytes()
597
598        auth_cmd =  AuthCommand()
599        sensitive = SensitiveCreate(user_auth=auth_value, data=data)
600
601        public = Public(
602            object_type=TPM2_ALG_KEYEDHASH,
603            name_alg=name_alg,
604            object_attributes=attributes,
605            auth_policy=policy_dig,
606            parameters=struct.pack('>H', TPM2_ALG_NULL))
607
608        fmt = '>HIII I%us H%us H%us HI' % \
609            (len(auth_cmd), len(sensitive), len(public))
610        cmd = struct.pack(
611            fmt,
612            TPM2_ST_SESSIONS,
613            struct.calcsize(fmt),
614            TPM2_CC_CREATE,
615            parent_key,
616            len(auth_cmd),
617            bytes(auth_cmd),
618            len(sensitive),
619            bytes(sensitive),
620            len(public),
621            bytes(public),
622            0, 0)
623
624        rsp = self.send_cmd(cmd)
625
626        return rsp[14:]
627
628    def unseal(self, parent_key, blob, auth_value, policy_handle):
629        private_len = struct.unpack('>H', blob[0:2])[0]
630        public_start = private_len + 2
631        public_len = struct.unpack('>H', blob[public_start:public_start + 2])[0]
632        blob = blob[:private_len + public_len + 4]
633
634        auth_cmd = AuthCommand()
635
636        fmt = '>HII I I%us %us' % (len(auth_cmd), len(blob))
637        cmd = struct.pack(
638            fmt,
639            TPM2_ST_SESSIONS,
640            struct.calcsize(fmt),
641            TPM2_CC_LOAD,
642            parent_key,
643            len(auth_cmd),
644            bytes(auth_cmd),
645            blob)
646
647        data_handle = struct.unpack('>I', self.send_cmd(cmd)[10:14])[0]
648
649        if policy_handle:
650            auth_cmd = AuthCommand(session_handle=policy_handle, hmac=auth_value)
651        else:
652            auth_cmd = AuthCommand(hmac=auth_value)
653
654        fmt = '>HII I I%us' % (len(auth_cmd))
655        cmd = struct.pack(
656            fmt,
657            TPM2_ST_SESSIONS,
658            struct.calcsize(fmt),
659            TPM2_CC_UNSEAL,
660            data_handle,
661            len(auth_cmd),
662            bytes(auth_cmd))
663
664        try:
665            rsp = self.send_cmd(cmd)
666        finally:
667            self.flush_context(data_handle)
668
669        data_len = struct.unpack('>I', rsp[10:14])[0] - 2
670
671        return rsp[16:16 + data_len]
672
673    def reset_da_lock(self):
674        auth_cmd = AuthCommand()
675
676        fmt = '>HII I I%us' % (len(auth_cmd))
677        cmd = struct.pack(
678            fmt,
679            TPM2_ST_SESSIONS,
680            struct.calcsize(fmt),
681            TPM2_CC_DICTIONARY_ATTACK_LOCK_RESET,
682            TPM2_RH_LOCKOUT,
683            len(auth_cmd),
684            bytes(auth_cmd))
685
686        self.send_cmd(cmd)
687
688    def __get_cap_cnt(self, cap, pt, cnt):
689        handles = []
690        fmt = '>HII III'
691
692        cmd = struct.pack(fmt,
693                          TPM2_ST_NO_SESSIONS,
694                          struct.calcsize(fmt),
695                          TPM2_CC_GET_CAPABILITY,
696                          cap, pt, cnt)
697
698        rsp = self.send_cmd(cmd)[10:]
699        more_data, cap, cnt = struct.unpack('>BII', rsp[:9])
700        rsp = rsp[9:]
701
702        for i in range(0, cnt):
703            handle = struct.unpack('>I', rsp[:4])[0]
704            handles.append(handle)
705            rsp = rsp[4:]
706
707        return handles, more_data
708
709    def get_cap(self, cap, pt):
710        handles = []
711
712        more_data = True
713        while more_data:
714            next_handles, more_data = self.__get_cap_cnt(cap, pt, 1)
715            handles += next_handles
716            pt += 1
717
718        return handles
719