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 · ARGUMENT the command line argument specifies the NV index or offset
75 number.
76 References
79 The type of a context object, whether it is a handle or file name, is
80 determined according to the following logic in-order:
81 · If the argument is a file path, then the file is loaded as a restored
83 TPM transient object.
84 · If the argument is a prefix match on one of:
86 · owner: the owner hierarchy
88 · platform: the platform hierarchy
90 · endorsement: the endorsement hierarchy
92 · lockout: the lockout control persistent object
94 · If the argument argument can be loaded as a number it will be treat
96 as a handle, e.g. 0x81010013 and used directly.OBJECT.
97
99 Authorization for use of an object in TPM2.0 can come in 3 different
100 forms: 1. Password 2. HMAC 3. Sessions
101 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
103 fied".
104 Passwords
106 Passwords are interpreted in the following forms below using prefix
107 identifiers.
108 Note: By default passwords are assumed to be in the string form when
110 they do not have a prefix.
111 String
113 A string password, specified by prefix "str:" or it's absence (raw
114 string without prefix) is not interpreted, and is directly used for au‐
115 thorization.
116 Examples
118 foobar
119 str:foobar
120 Hex-string
122 A hex-string password, specified by prefix "hex:" is converted from a
123 hexidecimal form into a byte array form, thus allowing passwords with
124 non-printable and/or terminal un-friendly characters.
125 Example
127 hex:0x1122334455667788
128 File
130 A file based password, specified be prefix "file:" should be the path
131 of a file containing the password to be read by the tool or a "-" to
132 use stdin. Storing passwords in files prevents information leakage,
133 passwords passed as options can be read from the process list or common
134 shell history features.
135 Examples
137 # to use stdin and be prompted
138 file:-
139 # to use a file from a path
141 file:path/to/password/file
142 # to echo a password via stdin:
144 echo foobar | tpm2_tool -p file:-
145 # to use a bash here-string via stdin:
147 tpm2_tool -p file:- <<< foobar
149 Sessions
151 When using a policy session to authorize the use of an object, prefix
152 the option argument with the session keyword. Then indicate a path to
153 a session file that was created with tpm2_startauthsession(1). Option‐
154 ally, if the session requires an auth value to be sent with the session
155 handle (eg policy password), then append a + and a string as described
156 in the Passwords section.
157 Examples
159 To use a session context file called session.ctx.
160 session:session.ctx
162 To use a session context file called session.ctx AND send the authvalue
164 mypassword.
165 session:session.ctx+mypassword
167 To use a session context file called session.ctx AND send the HEX auth‐
169 value 0x11223344.
170 session:session.ctx+hex:11223344
172 PCR Authorizations
174 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
175 language. The PCR minilanguage is as follows:
176 <pcr-spec>=<raw-pcr-file>
177 The PCR spec is documented in in the section "PCR bank specifiers".
179 The raw-pcr-file is an optional the output of the raw PCR contents as
181 returned by tpm2_pcrread(1).
182 PCR bank specifiers (common/pcr.md)
184 Examples
186 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
187 er of:
188 pcr:sha256:0,1,2,3
190 specifying AUTH.
192
194 Options that take algorithms support "nice-names".
195 There are two major algorithm specification string classes, simple and
197 complex. Only certain algorithms will be accepted by the TPM, based on
198 usage and conditions.
199 Simple specifiers
201 These are strings with no additional specification data. When creating
202 objects, non-specified portions of an object are assumed to defaults.
203 You can find the list of known "Simple Specifiers Below".
204 Asymmetric
206 · rsa
207 · ecc
209 Symmetric
211 · aes
212 · camellia
214 Hashing Algorithms
216 · sha1
217 · sha256
219 · sha384
221 · sha512
223 · sm3_256
225 · sha3_256
227 · sha3_384
229 · sha3_512
231 Keyed Hash
233 · hmac
234 · xor
236 Signing Schemes
238 · rsassa
239 · rsapss
241 · ecdsa
243 · ecdaa
245 · ecschnorr
247 Asymmetric Encryption Schemes
249 · oaep
250 · rsaes
252 · ecdh
254 Modes
256 · ctr
257 · ofb
259 · cbc
261 · cfb
263 · ecb
265 Misc
267 · null
268 Complex Specifiers
270 Objects, when specified for creation by the TPM, have numerous algo‐
271 rithms to populate in the public data. Things like type, scheme and
272 asymmetric details, key size, etc. Below is the general format for
273 specifying this data: <type>:<scheme>:<symmetric-details>
274 Type Specifiers
276 This portion of the complex algorithm specifier is required. The re‐
277 maining scheme and symmetric details will default based on the type
278 specified and the type of the object being created.
279 · aes - Default AES: aes128
281 · aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
283 If mode is not specified, defaults to null.
284 · aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
286 · aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
288 · ecc - Elliptical Curve, defaults to ecc256.
290 · ecc192 - 192 bit ECC
292 · ecc224 - 224 bit ECC
294 · ecc256 - 256 bit ECC
296 · ecc384 - 384 bit ECC
298 · ecc521 - 521 bit ECC
300 · rsa - Default RSA: rsa2048
302 · rsa1024 - RSA with 1024 bit keysize.
304 · rsa2048 - RSA with 2048 bit keysize.
306 · rsa4096 - RSA with 4096 bit keysize.
308 Scheme Specifiers
310 Next, is an optional field, it can be skipped.
311 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
313 Most signing schemes take a hash algorithm directly following the sign‐
314 ing scheme. If the hash algorithm is missing, it defaults to sha256.
315 Some take no arguments, and some take multiple arguments.
316 Hash Optional Scheme Specifiers
318 These scheme specifiers are followed by a dash and a valid hash algo‐
319 rithm, For example: oaep-sha256.
320 · oaep
322 · ecdh
324 · rsassa
326 · rsapss
328 · ecdsa
330 · ecschnorr
332 Multiple Option Scheme Specifiers
334 This scheme specifier is followed by a count (max size UINT16) then
335 folloed by a dash(-) and a valid hash algorithm. * ecdaa For example,
336 ecdaa4-sha256. If no count is specified, it defaults to 4.
337 No Option Scheme Specifiers
339 This scheme specifier takes NO arguments. * rsaes
340 Symmetric Details Specifiers
342 This field is optional, and defaults based on the type of object being
343 created and it's attributes. Generally, any valid Symmetric specifier
344 from the Type Specifiers list should work. If not specified, an asym‐
345 metric objects symmetric details defaults to aes128cfb.
346 Examples
348 Create an rsa2048 key with an rsaes asymmetric encryption scheme
349 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
350 Create an ecc256 key with an ecdaa signing scheme with a count of 4
352 and sha384 hash
353 /tpm2_create -C parent.ctx -G ecc256:ec‐
355 daa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
356
358 Format selection for the signature output file. tss (the default) will
359 output a binary blob according to the TPM 2.0 specification and any po‐
360 tential compiler padding. The option plain will output the plain sig‐
361 nature data as defined by the used cryptographic algorithm. signature
362 FORMAT.
363
365 This collection of options are common to many programs and provide in‐
366 formation that many users may expect.
367 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
369 attempts to invoke the manpager for the tool, however, on failure
370 will output a short tool summary. This is the same behavior if the
371 "man" option argument is specified, however if explicit "man" is re‐
372 quested, the tool will provide errors from man on stderr. If the
373 "no-man" option if specified, or the manpager fails, the short op‐
374 tions will be output to stdout.
375 To successfully use the manpages feature requires the manpages to be
377 installed or on MANPATH, See man(1) for more details.
378 · -v, --version: Display version information for this tool, supported
380 tctis and exit.
381 · -V, --verbose: Increase the information that the tool prints to the
383 console during its execution. When using this option the file and
384 line number are printed.
385 · -Q, --quiet: Silence normal tool output to stdout.
387 · -Z, --enable-errata: Enable the application of errata fixups. Useful
389 if an errata fixup needs to be applied to commands sent to the TPM.
390 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
391 formation many users may expect.
392
394 The TCTI or "Transmission Interface" is the communication mechanism
395 with the TPM. TCTIs can be changed for communication with TPMs across
396 different mediums.
397 To control the TCTI, the tools respect:
399 1. The command line option -T or --tcti
401 2. The environment variable: TPM2TOOLS_TCTI.
403 Note: The command line option always overrides the environment vari‐
405 able.
406 The current known TCTIs are:
408 · tabrmd - The resource manager, called tabrmd
410 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
411 abrmd as a tcti name are synonymous.
412 · mssim - Typically used for communicating to the TPM software simula‐
414 tor.
415 · device - Used when talking directly to a TPM device file.
417 · none - Do not initalize a connection with the TPM. Some tools allow
419 for off-tpm options and thus support not using a TCTI. Tools that do
420 not support it will error when attempted to be used without a TCTI
421 connection. Does not support ANY options and MUST BE presented as
422 the exact text of "none".
423 The arguments to either the command line option or the environment
425 variable are in the form:
426 <tcti-name>:<tcti-option-config>
428 Specifying an empty string for either the <tcti-name> or <tcti-op‐
430 tion-config> results in the default being used for that portion respec‐
431 tively.
432 TCTI Defaults
434 When a TCTI is not specified, the default TCTI is searched for using
435 dlopen(3) semantics. The tools will search for tabrmd, device and
436 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
437 what TCTI will be chosen as the default by using the -v option to print
438 the version information. The "default-tcti" key-value pair will indi‐
439 cate which of the aforementioned TCTIs is the default.
440 Custom TCTIs
442 Any TCTI that implements the dynamic TCTI interface can be loaded. The
443 tools internally use dlopen(3), and the raw tcti-name value is used for
444 the lookup. Thus, this could be a path to the shared library, or a li‐
445 brary name as understood by dlopen(3) semantics.
446
448 This collection of options are used to configure the various known TCTI
449 modules available:
450 · device: For the device TCTI, the TPM character device file for use by
452 the device TCTI can be specified. The default is /dev/tpm0.
453 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
455 vice:/dev/tpm0"
456 · mssim: For the mssim TCTI, the domain name or IP address and port
458 number used by the simulator can be specified. The default are
459 127.0.0.1 and 2321.
460 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
462 TI="mssim:host=localhost,port=2321"
463 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
465 ries of simple key value pairs separated by a ',' character. Each
466 key and value string are separated by a '=' character.
467 · TCTI abrmd supports two keys:
469 1. 'bus_name' : The name of the tabrmd service on the bus (a
471 string).
472 2. 'bus_type' : The type of the dbus instance (a string) limited to
474 'session' and 'system'.
475 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
477 ample.FooBar:
478 \--tcti=tabrmd:bus_name=com.example.FooBar
480 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
482 sion:
483 \--tcti:bus_type=session
485 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
487 ules.
488
490 tpm2_nvdefine -s 32 -a "authread|authwrite" 1
491 dd if=/dev/urandom bs=1 count=32 status=none| \
493 tpm2_nvwrite 1 -i-
494 tpm2_createprimary -C o -c primary.ctx -Q
496 tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx -c signing_key.ctx -Q
498 tpm2_readpublic -c signing_key.ctx -f pem -o sslpub.pem -Q
500 tpm2_nvcertify -C signing_key.ctx -g sha256 -f plain -s rsassa \
502 -o signature.bin --attestation attestation.bin --size 32 1
503
505 Tools can return any of the following codes:
506 · 0 - Success.
508 · 1 - General non-specific error.
510 · 2 - Options handling error.
512 · 3 - Authentication error.
514 · 4 - TCTI related error.
516 · 5 - Non supported scheme. Applicable to tpm2_testparams.
518
520 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
521
523 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
524tpm2-tools tpm2_nvcertify(1)