1tpm2_nvcertify(1) General Commands Manual tpm2_nvcertify(1)
2
6 tpm2_nvcertify(1) - Provides attestation of the contents of an NV in‐
7 dex.
8
10 tpm2_nvcertify [OPTIONS] [ARGUMENTS]
11
13 tpm2_nvcertify(1) - Provides attestation of the contents of an NV in‐
14 dex. NOTE: As part of the attestation output, the NV index contents
15 are revealed.
16
18 These options control the certification:
19 • -C, --signingkey-context=OBJECT:
21 The key object that signs the attestation structure.
23 • -P, --signingkey-auth=AUTH:
25 The authorization value provided for the object specified with -C.
27 • -c, --nvauthobj-context=OBJECT:
29 The object that is the authorization handle for the NV object. It is
31 either the NV index handle itself or the platform/ owner hierarchy
32 handle. If not specified it defaults to the NV index handle.
33 • -p, --nvauthobj-auth=AUTH:
35 The authorization value provided for the object specified with -c.
37 • -g, --hash-algorithm=ALGORITHM:
39 The hash algorithm to use in signature generation.
41 • -s, --scheme=ALGORITHM:
43 The signing scheme used to sign the attestation data.
45 • -f, --format=FORMAT:
47 Format selection for the signature output file.
49 • -o, --signature=FILE:
51 Output file name for the signature data.
53 • -q, --qualification=FILE_OR_HEX_STR:
55 Optional, the policy qualifier data that the signer can choose to in‐
57 clude in the signature. Can be either a hex string or path.
58 • --size=NATURAL_NUMBER:
60 Specifies the size of data to be read in bytes, starting from 0 if
62 offset is not specified. If not specified, the size of the data as
63 reported by the public portion of the index will be used.
64 • --offset=NATURAL_NUMBER:
66 The offset within the NV index to start reading from.
68 • –attestation=FILE:
70 The attestation data of the type TPM2_CREATION_INFO signed with sign‐
72 ing key.
73 • --cphash=FILE
75 File path to record the hash of the command parameters. This is com‐
77 monly termed as cpHash. NOTE: When this option is selected, The tool
78 will not actually execute the command, it simply returns a cpHash un‐
79 less rphash is also required.
80 • --rphash=FILE
82 File path to record the hash of the response parameters. This is
84 commonly termed as rpHash.
85 • -S, --session=FILE:
87 The session created using tpm2_startauthsession. This can be used to
89 specify an auxiliary session for auditing and or encryption/decryp‐
90 tion of the parameters.
91 • -n, --name=FILE:
93 The name of the NV index that must be provided when only calculating
95 the cpHash without actually dispatching the command to the TPM.
96 • -signer-name=FILE:
98 The name of the signing key that must be provided when only calculat‐
100 ing the cpHash without actually dispatching the command to the TPM.
101 • ARGUMENT the command line argument specifies the NV index or offset
103 number.
104 References
107 The type of a context object, whether it is a handle or file name, is
108 determined according to the following logic in-order:
109 • If the argument is a file path, then the file is loaded as a restored
111 TPM transient object.
112 • If the argument is a prefix match on one of:
114 • owner: the owner hierarchy
116 • platform: the platform hierarchy
118 • endorsement: the endorsement hierarchy
120 • lockout: the lockout control persistent object
122 • If the argument argument can be loaded as a number it will be treat
124 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
125
127 Authorization for use of an object in TPM2.0 can come in 3 different
128 forms: 1. Password 2. HMAC 3. Sessions
129 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
131 fied”.
132 Passwords
134 Passwords are interpreted in the following forms below using prefix
135 identifiers.
136 Note: By default passwords are assumed to be in the string form when
138 they do not have a prefix.
139 String
141 A string password, specified by prefix “str:” or it’s absence (raw
142 string without prefix) is not interpreted, and is directly used for au‐
143 thorization.
144 Examples
146 foobar
147 str:foobar
148 Hex-string
150 A hex-string password, specified by prefix “hex:” is converted from a
151 hexidecimal form into a byte array form, thus allowing passwords with
152 non-printable and/or terminal un-friendly characters.
153 Example
155 hex:1122334455667788
156 File
158 A file based password, specified be prefix “file:” should be the path
159 of a file containing the password to be read by the tool or a “-” to
160 use stdin. Storing passwords in files prevents information leakage,
161 passwords passed as options can be read from the process list or common
162 shell history features.
163 Examples
165 # to use stdin and be prompted
166 file:-
167 # to use a file from a path
169 file:path/to/password/file
170 # to echo a password via stdin:
172 echo foobar | tpm2_tool -p file:-
173 # to use a bash here-string via stdin:
175 tpm2_tool -p file:- <<< foobar
177 Sessions
179 When using a policy session to authorize the use of an object, prefix
180 the option argument with the session keyword. Then indicate a path to
181 a session file that was created with tpm2_startauthsession(1). Option‐
182 ally, if the session requires an auth value to be sent with the session
183 handle (eg policy password), then append a + and a string as described
184 in the Passwords section.
185 Examples
187 To use a session context file called session.ctx.
188 session:session.ctx
190 To use a session context file called session.ctx AND send the authvalue
192 mypassword.
193 session:session.ctx+mypassword
195 To use a session context file called session.ctx AND send the HEX auth‐
197 value 0x11223344.
198 session:session.ctx+hex:11223344
200 PCR Authorizations
202 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
203 language. The PCR minilanguage is as follows:
204 <pcr-spec>=<raw-pcr-file>
205 The PCR spec is documented in in the section “PCR bank specifiers”.
207 The raw-pcr-file is an optional argument that contains the output of
209 the raw PCR contents as returned by tpm2_pcrread(1).
210 PCR bank specifiers (pcr.md)
212 Examples
214 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
215 er of:
216 pcr:sha256:0,1,2,3
218 specifying AUTH.
220
222 Options that take algorithms support “nice-names”.
223 There are two major algorithm specification string classes, simple and
225 complex. Only certain algorithms will be accepted by the TPM, based on
226 usage and conditions.
227 Simple specifiers
229 These are strings with no additional specification data. When creating
230 objects, non-specified portions of an object are assumed to defaults.
231 You can find the list of known “Simple Specifiers” below.
232 Asymmetric
234 • rsa
235 • ecc
237 Symmetric
239 • aes
240 • camellia
242 • sm4
244 Hashing Algorithms
246 • sha1
247 • sha256
249 • sha384
251 • sha512
253 • sm3_256
255 • sha3_256
257 • sha3_384
259 • sha3_512
261 Keyed Hash
263 • hmac
264 • xor
266 Signing Schemes
268 • rsassa
269 • rsapss
271 • ecdsa
273 • ecdaa
275 • ecschnorr
277 • sm2
279 Asymmetric Encryption Schemes
281 • oaep
282 • rsaes
284 • ecdh
286 Modes
288 • ctr
289 • ofb
291 • cbc
293 • cfb
295 • ecb
297 Misc
299 • null
300 Complex Specifiers
302 Objects, when specified for creation by the TPM, have numerous algo‐
303 rithms to populate in the public data. Things like type, scheme and
304 asymmetric details, key size, etc. Below is the general format for
305 specifying this data: <type>:<scheme>:<symmetric-details>
306 Type Specifiers
308 This portion of the complex algorithm specifier is required. The re‐
309 maining scheme and symmetric details will default based on the type
310 specified and the type of the object being created.
311 • aes - Default AES: aes128
313 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
315 If mode is not specified, defaults to null.
316 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
318 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
320 • sm4 - Default SM4: sm4128
322 • sm4128 or sm4_128 <mode> - 128 bit SM4 with optional mode
324 (ctr|ofb|cbc|cfb|ecb). If mode is not specified, defaults to null.
325 • ecc - Elliptical Curve, defaults to ecc256.
327 • ecc192 or ecc_nist_p192 - 192 bit ECC NIST curve
329 • ecc224 or ecc_nist_p224 - 224 bit ECC NIST curve
331 • ecc256 or ecc_nist_p256 - 256 bit ECC NIST curve
333 • ecc384 or ecc_nist_p384 - 384 bit ECC NIST curve
335 • ecc521 or ecc_nist_p521 - 521 bit ECC NIST curve
337 • ecc_sm2 or ecc_sm2_p256 - 256 bit SM2 curve
339 • rsa - Default RSA: rsa2048
341 • rsa1024 - RSA with 1024 bit keysize.
343 • rsa2048 - RSA with 2048 bit keysize.
345 • rsa3072 - RSA with 3072 bit keysize.
347 • rsa4096 - RSA with 4096 bit keysize.
349 Scheme Specifiers
351 Next, is an optional field, it can be skipped.
352 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
354 Most signing schemes take a hash algorithm directly following the sign‐
355 ing scheme. If the hash algorithm is missing, it defaults to sha256.
356 Some take no arguments, and some take multiple arguments.
357 Hash Optional Scheme Specifiers
359 These scheme specifiers are followed by a dash and a valid hash algo‐
360 rithm, For example: oaep-sha256.
361 • oaep
363 • ecdh
365 • rsassa
367 • rsapss
369 • ecdsa
371 • ecschnorr
373 • sm2
375 Multiple Option Scheme Specifiers
377 This scheme specifier is followed by a count (max size UINT16) then
378 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
379 ecdaa4-sha256. If no count is specified, it defaults to 4.
380 No Option Scheme Specifiers
382 This scheme specifier takes NO arguments. * rsaes
383 Symmetric Details Specifiers
385 This field is optional, and defaults based on the type of object being
386 created and it’s attributes. Generally, any valid Symmetric specifier
387 from the Type Specifiers list should work. If not specified, an asym‐
388 metric objects symmetric details defaults to aes128cfb.
389 Examples
391 Create an rsa2048 key with an rsaes asymmetric encryption scheme
392 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
393 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
395 sha384 hash
396 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
397 key.priv cryptographic algorithms ALGORITHM.
398
400 Format selection for the signature output file. tss (the default) will
401 output a binary blob according to the TPM 2.0 specification and any po‐
402 tential compiler padding. The option plain will output the plain sig‐
403 nature data as defined by the used cryptographic algorithm. signature
404 FORMAT.
405
407 This collection of options are common to many programs and provide in‐
408 formation that many users may expect.
409 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
411 attempts to invoke the manpager for the tool, however, on failure
412 will output a short tool summary. This is the same behavior if the
413 “man” option argument is specified, however if explicit “man” is re‐
414 quested, the tool will provide errors from man on stderr. If the
415 “no-man” option if specified, or the manpager fails, the short op‐
416 tions will be output to stdout.
417 To successfully use the manpages feature requires the manpages to be
419 installed or on MANPATH, See man(1) for more details.
420 • -v, --version: Display version information for this tool, supported
422 tctis and exit.
423 • -V, --verbose: Increase the information that the tool prints to the
425 console during its execution. When using this option the file and
426 line number are printed.
427 • -Q, --quiet: Silence normal tool output to stdout.
429 • -Z, --enable-errata: Enable the application of errata fixups. Useful
431 if an errata fixup needs to be applied to commands sent to the TPM.
432 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
433 formation many users may expect.
434
436 The TCTI or “Transmission Interface” is the communication mechanism
437 with the TPM. TCTIs can be changed for communication with TPMs across
438 different mediums.
439 To control the TCTI, the tools respect:
441 1. The command line option -T or --tcti
443 2. The environment variable: TPM2TOOLS_TCTI.
445 Note: The command line option always overrides the environment vari‐
447 able.
448 The current known TCTIs are:
450 • tabrmd - The resource manager, called tabrmd
452 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
453 abrmd as a tcti name are synonymous.
454 • mssim - Typically used for communicating to the TPM software simula‐
456 tor.
457 • device - Used when talking directly to a TPM device file.
459 • none - Do not initalize a connection with the TPM. Some tools allow
461 for off-tpm options and thus support not using a TCTI. Tools that do
462 not support it will error when attempted to be used without a TCTI
463 connection. Does not support ANY options and MUST BE presented as
464 the exact text of “none”.
465 The arguments to either the command line option or the environment
467 variable are in the form:
468 <tcti-name>:<tcti-option-config>
470 Specifying an empty string for either the <tcti-name> or <tcti-op‐
472 tion-config> results in the default being used for that portion respec‐
473 tively.
474 TCTI Defaults
476 When a TCTI is not specified, the default TCTI is searched for using
477 dlopen(3) semantics. The tools will search for tabrmd, device and
478 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
479 what TCTI will be chosen as the default by using the -v option to print
480 the version information. The “default-tcti” key-value pair will indi‐
481 cate which of the aforementioned TCTIs is the default.
482 Custom TCTIs
484 Any TCTI that implements the dynamic TCTI interface can be loaded. The
485 tools internally use dlopen(3), and the raw tcti-name value is used for
486 the lookup. Thus, this could be a path to the shared library, or a li‐
487 brary name as understood by dlopen(3) semantics.
488
490 This collection of options are used to configure the various known TCTI
491 modules available:
492 • device: For the device TCTI, the TPM character device file for use by
494 the device TCTI can be specified. The default is /dev/tpm0.
495 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
497 vice:/dev/tpm0”
498 • mssim: For the mssim TCTI, the domain name or IP address and port
500 number used by the simulator can be specified. The default are
501 127.0.0.1 and 2321.
502 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
504 TI=“mssim:host=localhost,port=2321”
505 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
507 ries of simple key value pairs separated by a `,' character. Each
508 key and value string are separated by a `=' character.
509 • TCTI abrmd supports two keys:
511 1. `bus_name' : The name of the tabrmd service on the bus (a
513 string).
514 2. `bus_type' : The type of the dbus instance (a string) limited to
516 `session' and `system'.
517 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
519 ample.FooBar:
520 \--tcti=tabrmd:bus_name=com.example.FooBar
522 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
524 sion:
525 \--tcti:bus_type=session
527 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
529 ules.
530
532 tpm2_nvdefine -s 32 -a "authread|authwrite" 1
533 dd if=/dev/urandom bs=1 count=32 status=none| \
535 tpm2_nvwrite 1 -i-
536 tpm2_createprimary -C o -c primary.ctx -Q
538 tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx -c signing_key.ctx -Q
540 tpm2_readpublic -c signing_key.ctx -f pem -o sslpub.pem -Q
542 tpm2_nvcertify -C signing_key.ctx -g sha256 -f plain -s rsassa \
544 -o signature.bin --attestation attestation.bin --size 32 1
545
547 Tools can return any of the following codes:
548 • 0 - Success.
550 • 1 - General non-specific error.
552 • 2 - Options handling error.
554 • 3 - Authentication error.
556 • 4 - TCTI related error.
558 • 5 - Non supported scheme. Applicable to tpm2_testparams.
560
562 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
563
565 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
566 fo/tpm2)
567tpm2-tools tpm2_nvcertify(1)