1tpm2_verifysignature(1) General Commands Manual tpm2_verifysignature(1)
2
6 tpm2_verifysignature(1) - Validates a signature using the TPM.
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9 tpm2_verifysignature [OPTIONS]
10
12 tpm2_verifysignature(1) - Uses loaded keys to validate a signature on a
13 message with the message digest passed to the TPM. If the signature
14 check succeeds, then the TPM will produce a TPMT_TK_VERIFIED. Other‐
15 wise, the TPM shall return TPM_RC_SIGNATURE. If object references an
16 asymmetric key, only the public portion of the key needs to be loaded.
17 If object references a symmetric key, both the public and private por‐
18 tions need to be loaded.
19
21 • -c, --key-context=OBJECT:
22 Context object for the key context used for the operation. Either a
24 file or a handle number. See section “Context Object Format”.
25 • -g, --hash-algorithm=ALGORITHM:
27 The hash algorithm used to digest the message. Algorithms should
29 follow the “formatting standards”, see section “Algorithm Speci‐
30 fiers”. Also, see section “Supported Hash Algorithms” for a list of
31 supported hash algorithms.
32 • -m, --message=FILE:
34 The message file, containing the content to be digested.
36 • -d, --digest=FILE:
38 The input hash file, containing the hash of the message. If this op‐
40 tion is selected, then the message (-m) and algorithm (-g) options do
41 not need to be specified.
42 • -s, --signature=FILE:
44 The input signature file of the signature to be validated.
46 • -f, --scheme=SCHEME:
48 The signing scheme that was used to sign the message. This option
50 should only be specified if the signature comes in from a non tss
51 standard, like openssl. See “Signature format specifiers” for more
52 details. The tss format contains the signature metadata required to
53 understand it’s signature scheme.
54 Signing schemes should follow the “formatting standards”, see section
56 “Algorithm Specifiers”.
57 • --format=SCHEME:
59 Deprecated. Same as --scheme.
61 • -t, --ticket=FILE:
63 The ticket file to record the validation structure.
65 References
68 The type of a context object, whether it is a handle or file name, is
69 determined according to the following logic in-order:
70 • If the argument is a file path, then the file is loaded as a restored
72 TPM transient object.
73 • If the argument is a prefix match on one of:
75 • owner: the owner hierarchy
77 • platform: the platform hierarchy
79 • endorsement: the endorsement hierarchy
81 • lockout: the lockout control persistent object
83 • If the argument argument can be loaded as a number it will be treat
85 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
86
88 Options that take algorithms support “nice-names”.
89 There are two major algorithm specification string classes, simple and
91 complex. Only certain algorithms will be accepted by the TPM, based on
92 usage and conditions.
93 Simple specifiers
95 These are strings with no additional specification data. When creating
96 objects, non-specified portions of an object are assumed to defaults.
97 You can find the list of known “Simple Specifiers” below.
98 Asymmetric
100 • rsa
101 • ecc
103 Symmetric
105 • aes
106 • camellia
108 • sm4
110 Hashing Algorithms
112 • sha1
113 • sha256
115 • sha384
117 • sha512
119 • sm3_256
121 • sha3_256
123 • sha3_384
125 • sha3_512
127 Keyed Hash
129 • hmac
130 • xor
132 Signing Schemes
134 • rsassa
135 • rsapss
137 • ecdsa
139 • ecdaa
141 • ecschnorr
143 • sm2
145 Asymmetric Encryption Schemes
147 • oaep
148 • rsaes
150 • ecdh
152 Modes
154 • ctr
155 • ofb
157 • cbc
159 • cfb
161 • ecb
163 Misc
165 • null
166 Complex Specifiers
168 Objects, when specified for creation by the TPM, have numerous algo‐
169 rithms to populate in the public data. Things like type, scheme and
170 asymmetric details, key size, etc. Below is the general format for
171 specifying this data: <type>:<scheme>:<symmetric-details>
172 Type Specifiers
174 This portion of the complex algorithm specifier is required. The re‐
175 maining scheme and symmetric details will default based on the type
176 specified and the type of the object being created.
177 • aes - Default AES: aes128
179 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
181 If mode is not specified, defaults to null.
182 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
184 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
186 • sm4 - Default SM4: sm4128
188 • sm4128 or sm4_128 <mode> - 128 bit SM4 with optional mode
190 (ctr|ofb|cbc|cfb|ecb). If mode is not specified, defaults to null.
191 • ecc - Elliptical Curve, defaults to ecc256.
193 • ecc192 or ecc_nist_p192 - 192 bit ECC NIST curve
195 • ecc224 or ecc_nist_p224 - 224 bit ECC NIST curve
197 • ecc256 or ecc_nist_p256 - 256 bit ECC NIST curve
199 • ecc384 or ecc_nist_p384 - 384 bit ECC NIST curve
201 • ecc521 or ecc_nist_p521 - 521 bit ECC NIST curve
203 • ecc_sm2 or ecc_sm2_p256 - 256 bit SM2 curve
205 • rsa - Default RSA: rsa2048
207 • rsa1024 - RSA with 1024 bit keysize.
209 • rsa2048 - RSA with 2048 bit keysize.
211 • rsa3072 - RSA with 3072 bit keysize.
213 • rsa4096 - RSA with 4096 bit keysize.
215 Scheme Specifiers
217 Next, is an optional field, it can be skipped.
218 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
220 Most signing schemes take a hash algorithm directly following the sign‐
221 ing scheme. If the hash algorithm is missing, it defaults to sha256.
222 Some take no arguments, and some take multiple arguments.
223 Hash Optional Scheme Specifiers
225 These scheme specifiers are followed by a dash and a valid hash algo‐
226 rithm, For example: oaep-sha256.
227 • oaep
229 • ecdh
231 • rsassa
233 • rsapss
235 • ecdsa
237 • ecschnorr
239 • sm2
241 Multiple Option Scheme Specifiers
243 This scheme specifier is followed by a count (max size UINT16) then
244 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
245 ecdaa4-sha256. If no count is specified, it defaults to 4.
246 No Option Scheme Specifiers
248 This scheme specifier takes NO arguments. * rsaes
249 Symmetric Details Specifiers
251 This field is optional, and defaults based on the type of object being
252 created and it’s attributes. Generally, any valid Symmetric specifier
253 from the Type Specifiers list should work. If not specified, an asym‐
254 metric objects symmetric details defaults to aes128cfb.
255 Examples
257 Create an rsa2048 key with an rsaes asymmetric encryption scheme
258 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
259 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
261 sha384 hash
262 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
263 key.priv cryptographic algorithms ALGORITHM.
264
266 This collection of options are common to many programs and provide in‐
267 formation that many users may expect.
268 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
270 attempts to invoke the manpager for the tool, however, on failure
271 will output a short tool summary. This is the same behavior if the
272 “man” option argument is specified, however if explicit “man” is re‐
273 quested, the tool will provide errors from man on stderr. If the
274 “no-man” option if specified, or the manpager fails, the short op‐
275 tions will be output to stdout.
276 To successfully use the manpages feature requires the manpages to be
278 installed or on MANPATH, See man(1) for more details.
279 • -v, --version: Display version information for this tool, supported
281 tctis and exit.
282 • -V, --verbose: Increase the information that the tool prints to the
284 console during its execution. When using this option the file and
285 line number are printed.
286 • -Q, --quiet: Silence normal tool output to stdout.
288 • -Z, --enable-errata: Enable the application of errata fixups. Useful
290 if an errata fixup needs to be applied to commands sent to the TPM.
291 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
292 formation many users may expect.
293
295 The TCTI or “Transmission Interface” is the communication mechanism
296 with the TPM. TCTIs can be changed for communication with TPMs across
297 different mediums.
298 To control the TCTI, the tools respect:
300 1. The command line option -T or --tcti
302 2. The environment variable: TPM2TOOLS_TCTI.
304 Note: The command line option always overrides the environment vari‐
306 able.
307 The current known TCTIs are:
309 • tabrmd - The resource manager, called tabrmd
311 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
312 abrmd as a tcti name are synonymous.
313 • mssim - Typically used for communicating to the TPM software simula‐
315 tor.
316 • device - Used when talking directly to a TPM device file.
318 • none - Do not initalize a connection with the TPM. Some tools allow
320 for off-tpm options and thus support not using a TCTI. Tools that do
321 not support it will error when attempted to be used without a TCTI
322 connection. Does not support ANY options and MUST BE presented as
323 the exact text of “none”.
324 The arguments to either the command line option or the environment
326 variable are in the form:
327 <tcti-name>:<tcti-option-config>
329 Specifying an empty string for either the <tcti-name> or <tcti-op‐
331 tion-config> results in the default being used for that portion respec‐
332 tively.
333 TCTI Defaults
335 When a TCTI is not specified, the default TCTI is searched for using
336 dlopen(3) semantics. The tools will search for tabrmd, device and
337 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
338 what TCTI will be chosen as the default by using the -v option to print
339 the version information. The “default-tcti” key-value pair will indi‐
340 cate which of the aforementioned TCTIs is the default.
341 Custom TCTIs
343 Any TCTI that implements the dynamic TCTI interface can be loaded. The
344 tools internally use dlopen(3), and the raw tcti-name value is used for
345 the lookup. Thus, this could be a path to the shared library, or a li‐
346 brary name as understood by dlopen(3) semantics.
347
349 This collection of options are used to configure the various known TCTI
350 modules available:
351 • device: For the device TCTI, the TPM character device file for use by
353 the device TCTI can be specified. The default is /dev/tpm0.
354 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
356 vice:/dev/tpm0”
357 • mssim: For the mssim TCTI, the domain name or IP address and port
359 number used by the simulator can be specified. The default are
360 127.0.0.1 and 2321.
361 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
363 TI=“mssim:host=localhost,port=2321”
364 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
366 ries of simple key value pairs separated by a `,' character. Each
367 key and value string are separated by a `=' character.
368 • TCTI abrmd supports two keys:
370 1. `bus_name' : The name of the tabrmd service on the bus (a
372 string).
373 2. `bus_type' : The type of the dbus instance (a string) limited to
375 `session' and `system'.
376 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
378 ample.FooBar:
379 \--tcti=tabrmd:bus_name=com.example.FooBar
381 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
383 sion:
384 \--tcti:bus_type=session
386 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
388 ules.
389
391 Format selection for the signature output file. tss (the default) will
392 output a binary blob according to the TPM 2.0 specification and any po‐
393 tential compiler padding. The option plain will output the plain sig‐
394 nature data as defined by the used cryptographic algorithm.
395
397 Sign and verify with the TPM using the endorsement hierarchy
398 tpm2_createprimary -C e -c primary.ctx
399 tpm2_create -G rsa -u rsa.pub -r rsa.priv -C primary.ctx
401 tpm2_load -C primary.ctx -u rsa.pub -r rsa.priv -c rsa.ctx
403 echo "my message > message.dat
405 tpm2_sign -c rsa.ctx -g sha256 -m message.dat -s sig.rssa
407 tpm2_verifysignature -c rsa.ctx -g sha256 -m message.dat -s sig.rssa
409 Sign with openssl and verify with the TPM
411 # Generate an ECC key
412 openssl ecparam -name prime256v1 -genkey -noout -out private.ecc.pem
413 openssl ec -in private.ecc.pem -out public.ecc.pem -pubout
415 # Generate a hash to sign (OSSL needs the hash of the message)
417 echo "data to sign" > data.in.raw
418 sha256sum data.in.raw | awk '{ print "000000 " $1 }' | \
420 xxd -r -c 32 > data.in.digest
421 # Load the private key for signing
423 tpm2_loadexternal -Q -G ecc -r private.ecc.pem -c key.ctx
424 # Sign in the TPM and verify with OSSL
426 tpm2_sign -Q -c key.ctx -g sha256 -d data.in.digest -f plain -s data.out.signed
427 openssl dgst -verify public.ecc.pem -keyform pem -sha256 \
429 -signature data.out.signed data.in.raw
430 # Sign with openssl and verify with TPM
432 openssl dgst -sha256 -sign private.ecc.pem -out data.out.signed data.in.raw
433 tpm2_verifysignature -Q -c key.ctx -g sha256 -m data.in.raw -f ecdsa \
435 -s data.out.signed
436
438 Tools can return any of the following codes:
439 • 0 - Success.
441 • 1 - General non-specific error.
443 • 2 - Options handling error.
445 • 3 - Authentication error.
447 • 4 - TCTI related error.
449 • 5 - Non supported scheme. Applicable to tpm2_testparams.
451
453 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
454
456 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
457 fo/tpm2)
458tpm2-tools tpm2_verifysignature(1)