1tpm2_pcrread(1) General Commands Manual tpm2_pcrread(1)
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6 tpm2_pcrread(1) - List PCR values.
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9 tpm2_pcrread [OPTIONS] PCR_LIST_OR_ALG
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12 tpm2_pcrread(1) - Displays PCR values. Without any arguments,
13 tpm2_pcrread(1) outputs all PCRs and their hash banks. One can use
14 specify the hash algorithm or a pcr list as an argument to filter the
15 output.
16 To only output PCR banks with a given algorithm, specify the hashing
18 algorithm as the argument. Algorithms should follow the “formatting
19 standards”, see section “Algorithm Specifiers”. Also, see section
20 “Supported Hash Algorithms” for a list of supported hash algorithms.
21 To output a list of PCR banks (sha1, sha256, etc) and ids (0, 1, 2 etc)
23 specify a PCR selection list as the argument as specified via section
24 “PCR Bank Specifiers”.
25 Also read NOTES section below.
27 Output is written in a YAML format to stdout, with each algorithm fol‐
29 lowed by a PCR index and its value. As a simple example assume just
30 sha1 and sha256 support and only 1 PCR. The output would be:
31 $ tpm2_pcrread sha1:0+sha256:0
33 sha1 :
34 0 : 0000000000000000000000000000000000000003
35 sha256 :
36 0 : 0000000000000000000000000000000000000000000000000000000000000003
37
39 • -o, --output=FILE:
40 The output file to write the PCR values in binary format, optional.
42 • --cphash=FILE
44 File path to record the hash of the command parameters. This is com‐
46 monly termed as cpHash. NOTE: When this option is selected, The tool
47 will not actually execute the command, it simply returns a cpHash.
48 • -F, --pcrs_format=FORMAT:
50 Format selection for the binary blob in the PCR output file. `val‐
52 ues' will output a binary blob of the PCR values. `serialized' will
53 output a binary blob of the PCR values in the form of serialized data
54 structure in little endian format. Optional. Default is `values'.
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57 This collection of options are common to many programs and provide in‐
58 formation that many users may expect.
59 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
61 attempts to invoke the manpager for the tool, however, on failure
62 will output a short tool summary. This is the same behavior if the
63 “man” option argument is specified, however if explicit “man” is re‐
64 quested, the tool will provide errors from man on stderr. If the
65 “no-man” option if specified, or the manpager fails, the short op‐
66 tions will be output to stdout.
67 To successfully use the manpages feature requires the manpages to be
69 installed or on MANPATH, See man(1) for more details.
70 • -v, --version: Display version information for this tool, supported
72 tctis and exit.
73 • -V, --verbose: Increase the information that the tool prints to the
75 console during its execution. When using this option the file and
76 line number are printed.
77 • -Q, --quiet: Silence normal tool output to stdout.
79 • -Z, --enable-errata: Enable the application of errata fixups. Useful
81 if an errata fixup needs to be applied to commands sent to the TPM.
82 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
83
85 The TCTI or “Transmission Interface” is the communication mechanism
86 with the TPM. TCTIs can be changed for communication with TPMs across
87 different mediums.
88 To control the TCTI, the tools respect:
90 1. The command line option -T or --tcti
92 2. The environment variable: TPM2TOOLS_TCTI.
94 Note: The command line option always overrides the environment vari‐
96 able.
97 The current known TCTIs are:
99 • tabrmd - The resource manager, called tabrmd
101 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
102 abrmd as a tcti name are synonymous.
103 • mssim - Typically used for communicating to the TPM software simula‐
105 tor.
106 • device - Used when talking directly to a TPM device file.
108 • none - Do not initalize a connection with the TPM. Some tools allow
110 for off-tpm options and thus support not using a TCTI. Tools that do
111 not support it will error when attempted to be used without a TCTI
112 connection. Does not support ANY options and MUST BE presented as
113 the exact text of “none”.
114 The arguments to either the command line option or the environment
116 variable are in the form:
117 <tcti-name>:<tcti-option-config>
119 Specifying an empty string for either the <tcti-name> or <tcti-op‐
121 tion-config> results in the default being used for that portion respec‐
122 tively.
123 TCTI Defaults
125 When a TCTI is not specified, the default TCTI is searched for using
126 dlopen(3) semantics. The tools will search for tabrmd, device and
127 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
128 what TCTI will be chosen as the default by using the -v option to print
129 the version information. The “default-tcti” key-value pair will indi‐
130 cate which of the aforementioned TCTIs is the default.
131 Custom TCTIs
133 Any TCTI that implements the dynamic TCTI interface can be loaded. The
134 tools internally use dlopen(3), and the raw tcti-name value is used for
135 the lookup. Thus, this could be a path to the shared library, or a li‐
136 brary name as understood by dlopen(3) semantics.
137
139 This collection of options are used to configure the various known TCTI
140 modules available:
141 • device: For the device TCTI, the TPM character device file for use by
143 the device TCTI can be specified. The default is /dev/tpm0.
144 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
146 vice:/dev/tpm0”
147 • mssim: For the mssim TCTI, the domain name or IP address and port
149 number used by the simulator can be specified. The default are
150 127.0.0.1 and 2321.
151 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
153 TI=“mssim:host=localhost,port=2321”
154 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
156 ries of simple key value pairs separated by a `,' character. Each
157 key and value string are separated by a `=' character.
158 • TCTI abrmd supports two keys:
160 1. `bus_name' : The name of the tabrmd service on the bus (a
162 string).
163 2. `bus_type' : The type of the dbus instance (a string) limited to
165 `session' and `system'.
166 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
168 ample.FooBar:
169 \--tcti=tabrmd:bus_name=com.example.FooBar
171 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
173 sion:
174 \--tcti:bus_type=session
176 NOTE: abrmd and tabrmd are synonymous.
178 PCR bank specifiers (common/pcr.md)
180
182 Supported hash algorithms are:
183 • 0x4 or sha1 for TPM_ALG_SHA1
185 • 0xB or sha256 for TPM_ALG_SHA256 (default)
187 • 0xC or sha384 for TPM_ALG_SHA384
189 • 0xD or sha512 for TPM_ALG_SHA512
191 • 0x12 or sm3_256 for TPM_ALG_SM3_256
193 NOTE: Your TPM may not support all algorithms.
195
197 Options that take algorithms support “nice-names”.
198 There are two major algorithm specification string classes, simple and
200 complex. Only certain algorithms will be accepted by the TPM, based on
201 usage and conditions.
202 Simple specifiers
204 These are strings with no additional specification data. When creating
205 objects, non-specified portions of an object are assumed to defaults.
206 You can find the list of known “Simple Specifiers” below.
207 Asymmetric
209 • rsa
210 • ecc
212 Symmetric
214 • aes
215 • camellia
217 • sm4
219 Hashing Algorithms
221 • sha1
222 • sha256
224 • sha384
226 • sha512
228 • sm3_256
230 • sha3_256
232 • sha3_384
234 • sha3_512
236 Keyed Hash
238 • hmac
239 • xor
241 Signing Schemes
243 • rsassa
244 • rsapss
246 • ecdsa
248 • ecdaa
250 • ecschnorr
252 • sm2
254 Asymmetric Encryption Schemes
256 • oaep
257 • rsaes
259 • ecdh
261 Modes
263 • ctr
264 • ofb
266 • cbc
268 • cfb
270 • ecb
272 Misc
274 • null
275 Complex Specifiers
277 Objects, when specified for creation by the TPM, have numerous algo‐
278 rithms to populate in the public data. Things like type, scheme and
279 asymmetric details, key size, etc. Below is the general format for
280 specifying this data: <type>:<scheme>:<symmetric-details>
281 Type Specifiers
283 This portion of the complex algorithm specifier is required. The re‐
284 maining scheme and symmetric details will default based on the type
285 specified and the type of the object being created.
286 • aes - Default AES: aes128
288 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
290 If mode is not specified, defaults to null.
291 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
293 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
295 • sm4 - Default SM4: sm4128
297 • sm4128 or sm4_128 <mode> - 128 bit SM4 with optional mode
299 (ctr|ofb|cbc|cfb|ecb). If mode is not specified, defaults to null.
300 • ecc - Elliptical Curve, defaults to ecc256.
302 • ecc192 or ecc_nist_p192 - 192 bit ECC NIST curve
304 • ecc224 or ecc_nist_p224 - 224 bit ECC NIST curve
306 • ecc256 or ecc_nist_p256 - 256 bit ECC NIST curve
308 • ecc384 or ecc_nist_p384 - 384 bit ECC NIST curve
310 • ecc521 or ecc_nist_p521 - 521 bit ECC NIST curve
312 • ecc_sm2 or ecc_sm2_p256 - 256 bit SM2 curve
314 • rsa - Default RSA: rsa2048
316 • rsa1024 - RSA with 1024 bit keysize.
318 • rsa2048 - RSA with 2048 bit keysize.
320 • rsa3072 - RSA with 3072 bit keysize.
322 • rsa4096 - RSA with 4096 bit keysize.
324 Scheme Specifiers
326 Next, is an optional field, it can be skipped.
327 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
329 Most signing schemes take a hash algorithm directly following the sign‐
330 ing scheme. If the hash algorithm is missing, it defaults to sha256.
331 Some take no arguments, and some take multiple arguments.
332 Hash Optional Scheme Specifiers
334 These scheme specifiers are followed by a dash and a valid hash algo‐
335 rithm, For example: oaep-sha256.
336 • oaep
338 • ecdh
340 • rsassa
342 • rsapss
344 • ecdsa
346 • ecschnorr
348 • sm2
350 Multiple Option Scheme Specifiers
352 This scheme specifier is followed by a count (max size UINT16) then
353 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
354 ecdaa4-sha256. If no count is specified, it defaults to 4.
355 No Option Scheme Specifiers
357 This scheme specifier takes NO arguments. * rsaes
358 Symmetric Details Specifiers
360 This field is optional, and defaults based on the type of object being
361 created and it’s attributes. Generally, any valid Symmetric specifier
362 from the Type Specifiers list should work. If not specified, an asym‐
363 metric objects symmetric details defaults to aes128cfb.
364 Examples
366 Create an rsa2048 key with an rsaes asymmetric encryption scheme
367 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
368 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
370 sha384 hash
371 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
372 key.priv
373
375 Display all PCR values
376 tpm2_pcrread
377 Display the PCR values with a specified bank
379 tpm2_pcrread sha1
380 Display the PCR values with specified banks and store in a file
382 tpm2_pcrread -o pcrs sha1:16,17,18+sha256:16,17,18
383 Display the supported PCR bank algorithms and exit
385 tpm2_pcrread
386
388 The maximum number of PCR that can be dumped at once is associated with
389 the maximum length of a bank.
390 On most TPMs, it means that this tool can dump up to 24 PCRs at once.
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394 Tools can return any of the following codes:
395 • 0 - Success.
397 • 1 - General non-specific error.
399 • 2 - Options handling error.
401 • 3 - Authentication error.
403 • 4 - TCTI related error.
405 • 5 - Non supported scheme. Applicable to tpm2_testparams.
407
409 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
410
412 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
413 fo/tpm2)
414tpm2-tools tpm2_pcrread(1)