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.
79 • ARGUMENT the command line argument specifies the NV index or offset
81 number.
82 References
85 The type of a context object, whether it is a handle or file name, is
86 determined according to the following logic in-order:
87 • If the argument is a file path, then the file is loaded as a restored
89 TPM transient object.
90 • If the argument is a prefix match on one of:
92 • owner: the owner hierarchy
94 • platform: the platform hierarchy
96 • endorsement: the endorsement hierarchy
98 • lockout: the lockout control persistent object
100 • If the argument argument can be loaded as a number it will be treat
102 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
103
105 Authorization for use of an object in TPM2.0 can come in 3 different
106 forms: 1. Password 2. HMAC 3. Sessions
107 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
109 fied”.
110 Passwords
112 Passwords are interpreted in the following forms below using prefix
113 identifiers.
114 Note: By default passwords are assumed to be in the string form when
116 they do not have a prefix.
117 String
119 A string password, specified by prefix “str:” or it’s absence (raw
120 string without prefix) is not interpreted, and is directly used for au‐
121 thorization.
122 Examples
124 foobar
125 str:foobar
126 Hex-string
128 A hex-string password, specified by prefix “hex:” is converted from a
129 hexidecimal form into a byte array form, thus allowing passwords with
130 non-printable and/or terminal un-friendly characters.
131 Example
133 hex:0x1122334455667788
134 File
136 A file based password, specified be prefix “file:” should be the path
137 of a file containing the password to be read by the tool or a “-” to
138 use stdin. Storing passwords in files prevents information leakage,
139 passwords passed as options can be read from the process list or common
140 shell history features.
141 Examples
143 # to use stdin and be prompted
144 file:-
145 # to use a file from a path
147 file:path/to/password/file
148 # to echo a password via stdin:
150 echo foobar | tpm2_tool -p file:-
151 # to use a bash here-string via stdin:
153 tpm2_tool -p file:- <<< foobar
155 Sessions
157 When using a policy session to authorize the use of an object, prefix
158 the option argument with the session keyword. Then indicate a path to
159 a session file that was created with tpm2_startauthsession(1). Option‐
160 ally, if the session requires an auth value to be sent with the session
161 handle (eg policy password), then append a + and a string as described
162 in the Passwords section.
163 Examples
165 To use a session context file called session.ctx.
166 session:session.ctx
168 To use a session context file called session.ctx AND send the authvalue
170 mypassword.
171 session:session.ctx+mypassword
173 To use a session context file called session.ctx AND send the HEX auth‐
175 value 0x11223344.
176 session:session.ctx+hex:11223344
178 PCR Authorizations
180 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
181 language. The PCR minilanguage is as follows:
182 <pcr-spec>=<raw-pcr-file>
183 The PCR spec is documented in in the section “PCR bank specifiers”.
185 The raw-pcr-file is an optional argument that contains the output of
187 the raw PCR contents as returned by tpm2_pcrread(1).
188 PCR bank specifiers (pcr.md)
190 Examples
192 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
193 er of:
194 pcr:sha256:0,1,2,3
196 specifying AUTH.
198
200 Options that take algorithms support “nice-names”.
201 There are two major algorithm specification string classes, simple and
203 complex. Only certain algorithms will be accepted by the TPM, based on
204 usage and conditions.
205 Simple specifiers
207 These are strings with no additional specification data. When creating
208 objects, non-specified portions of an object are assumed to defaults.
209 You can find the list of known “Simple Specifiers Below”.
210 Asymmetric
212 • rsa
213 • ecc
215 Symmetric
217 • aes
218 • camellia
220 Hashing Algorithms
222 • sha1
223 • sha256
225 • sha384
227 • sha512
229 • sm3_256
231 • sha3_256
233 • sha3_384
235 • sha3_512
237 Keyed Hash
239 • hmac
240 • xor
242 Signing Schemes
244 • rsassa
245 • rsapss
247 • ecdsa
249 • ecdaa
251 • ecschnorr
253 Asymmetric Encryption Schemes
255 • oaep
256 • rsaes
258 • ecdh
260 Modes
262 • ctr
263 • ofb
265 • cbc
267 • cfb
269 • ecb
271 Misc
273 • null
274 Complex Specifiers
276 Objects, when specified for creation by the TPM, have numerous algo‐
277 rithms to populate in the public data. Things like type, scheme and
278 asymmetric details, key size, etc. Below is the general format for
279 specifying this data: <type>:<scheme>:<symmetric-details>
280 Type Specifiers
282 This portion of the complex algorithm specifier is required. The re‐
283 maining scheme and symmetric details will default based on the type
284 specified and the type of the object being created.
285 • aes - Default AES: aes128
287 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
289 If mode is not specified, defaults to null.
290 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
292 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
294 • ecc - Elliptical Curve, defaults to ecc256.
296 • ecc192 - 192 bit ECC
298 • ecc224 - 224 bit ECC
300 • ecc256 - 256 bit ECC
302 • ecc384 - 384 bit ECC
304 • ecc521 - 521 bit ECC
306 • rsa - Default RSA: rsa2048
308 • rsa1024 - RSA with 1024 bit keysize.
310 • rsa2048 - RSA with 2048 bit keysize.
312 • rsa4096 - RSA with 4096 bit keysize.
314 Scheme Specifiers
316 Next, is an optional field, it can be skipped.
317 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
319 Most signing schemes take a hash algorithm directly following the sign‐
320 ing scheme. If the hash algorithm is missing, it defaults to sha256.
321 Some take no arguments, and some take multiple arguments.
322 Hash Optional Scheme Specifiers
324 These scheme specifiers are followed by a dash and a valid hash algo‐
325 rithm, For example: oaep-sha256.
326 • oaep
328 • ecdh
330 • rsassa
332 • rsapss
334 • ecdsa
336 • ecschnorr
338 Multiple Option Scheme Specifiers
340 This scheme specifier is followed by a count (max size UINT16) then
341 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
342 ecdaa4-sha256. If no count is specified, it defaults to 4.
343 No Option Scheme Specifiers
345 This scheme specifier takes NO arguments. * rsaes
346 Symmetric Details Specifiers
348 This field is optional, and defaults based on the type of object being
349 created and it’s attributes. Generally, any valid Symmetric specifier
350 from the Type Specifiers list should work. If not specified, an asym‐
351 metric objects symmetric details defaults to aes128cfb.
352 Examples
354 Create an rsa2048 key with an rsaes asymmetric encryption scheme
355 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
356 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
358 sha384 hash
359 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
360 key.priv cryptographic algorithms ALGORITHM.
361
363 Format selection for the signature output file. tss (the default) will
364 output a binary blob according to the TPM 2.0 specification and any po‐
365 tential compiler padding. The option plain will output the plain sig‐
366 nature data as defined by the used cryptographic algorithm. signature
367 FORMAT.
368
370 This collection of options are common to many programs and provide in‐
371 formation that many users may expect.
372 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
374 attempts to invoke the manpager for the tool, however, on failure
375 will output a short tool summary. This is the same behavior if the
376 “man” option argument is specified, however if explicit “man” is re‐
377 quested, the tool will provide errors from man on stderr. If the
378 “no-man” option if specified, or the manpager fails, the short op‐
379 tions will be output to stdout.
380 To successfully use the manpages feature requires the manpages to be
382 installed or on MANPATH, See man(1) for more details.
383 • -v, --version: Display version information for this tool, supported
385 tctis and exit.
386 • -V, --verbose: Increase the information that the tool prints to the
388 console during its execution. When using this option the file and
389 line number are printed.
390 • -Q, --quiet: Silence normal tool output to stdout.
392 • -Z, --enable-errata: Enable the application of errata fixups. Useful
394 if an errata fixup needs to be applied to commands sent to the TPM.
395 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
396 formation many users may expect.
397
399 The TCTI or “Transmission Interface” is the communication mechanism
400 with the TPM. TCTIs can be changed for communication with TPMs across
401 different mediums.
402 To control the TCTI, the tools respect:
404 1. The command line option -T or --tcti
406 2. The environment variable: TPM2TOOLS_TCTI.
408 Note: The command line option always overrides the environment vari‐
410 able.
411 The current known TCTIs are:
413 • tabrmd - The resource manager, called tabrmd
415 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
416 abrmd as a tcti name are synonymous.
417 • mssim - Typically used for communicating to the TPM software simula‐
419 tor.
420 • device - Used when talking directly to a TPM device file.
422 • none - Do not initalize a connection with the TPM. Some tools allow
424 for off-tpm options and thus support not using a TCTI. Tools that do
425 not support it will error when attempted to be used without a TCTI
426 connection. Does not support ANY options and MUST BE presented as
427 the exact text of “none”.
428 The arguments to either the command line option or the environment
430 variable are in the form:
431 <tcti-name>:<tcti-option-config>
433 Specifying an empty string for either the <tcti-name> or <tcti-op‐
435 tion-config> results in the default being used for that portion respec‐
436 tively.
437 TCTI Defaults
439 When a TCTI is not specified, the default TCTI is searched for using
440 dlopen(3) semantics. The tools will search for tabrmd, device and
441 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
442 what TCTI will be chosen as the default by using the -v option to print
443 the version information. The “default-tcti” key-value pair will indi‐
444 cate which of the aforementioned TCTIs is the default.
445 Custom TCTIs
447 Any TCTI that implements the dynamic TCTI interface can be loaded. The
448 tools internally use dlopen(3), and the raw tcti-name value is used for
449 the lookup. Thus, this could be a path to the shared library, or a li‐
450 brary name as understood by dlopen(3) semantics.
451
453 This collection of options are used to configure the various known TCTI
454 modules available:
455 • device: For the device TCTI, the TPM character device file for use by
457 the device TCTI can be specified. The default is /dev/tpm0.
458 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
460 vice:/dev/tpm0”
461 • mssim: For the mssim TCTI, the domain name or IP address and port
463 number used by the simulator can be specified. The default are
464 127.0.0.1 and 2321.
465 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
467 TI=“mssim:host=localhost,port=2321”
468 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
470 ries of simple key value pairs separated by a `,' character. Each
471 key and value string are separated by a `=' character.
472 • TCTI abrmd supports two keys:
474 1. `bus_name' : The name of the tabrmd service on the bus (a
476 string).
477 2. `bus_type' : The type of the dbus instance (a string) limited to
479 `session' and `system'.
480 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
482 ample.FooBar:
483 \--tcti=tabrmd:bus_name=com.example.FooBar
485 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
487 sion:
488 \--tcti:bus_type=session
490 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
492 ules.
493
495 tpm2_nvdefine -s 32 -a "authread|authwrite" 1
496 dd if=/dev/urandom bs=1 count=32 status=none| \
498 tpm2_nvwrite 1 -i-
499 tpm2_createprimary -C o -c primary.ctx -Q
501 tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx -c signing_key.ctx -Q
503 tpm2_readpublic -c signing_key.ctx -f pem -o sslpub.pem -Q
505 tpm2_nvcertify -C signing_key.ctx -g sha256 -f plain -s rsassa \
507 -o signature.bin --attestation attestation.bin --size 32 1
508
510 Tools can return any of the following codes:
511 • 0 - Success.
513 • 1 - General non-specific error.
515 • 2 - Options handling error.
517 • 3 - Authentication error.
519 • 4 - TCTI related error.
521 • 5 - Non supported scheme. Applicable to tpm2_testparams.
523
525 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
526
528 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
529tpm2-tools tpm2_nvcertify(1)