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.
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44 This collection of options are common to many programs and provide in‐
45 formation that many users may expect.
46 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
48 attempts to invoke the manpager for the tool, however, on failure
49 will output a short tool summary. This is the same behavior if the
50 "man" option argument is specified, however if explicit "man" is re‐
51 quested, the tool will provide errors from man on stderr. If the
52 "no-man" option if specified, or the manpager fails, the short op‐
53 tions will be output to stdout.
54 To successfully use the manpages feature requires the manpages to be
56 installed or on MANPATH, See man(1) for more details.
57 • -v, --version: Display version information for this tool, supported
59 tctis and exit.
60 • -V, --verbose: Increase the information that the tool prints to the
62 console during its execution. When using this option the file and
63 line number are printed.
64 • -Q, --quiet: Silence normal tool output to stdout.
66 • -Z, --enable-errata: Enable the application of errata fixups. Useful
68 if an errata fixup needs to be applied to commands sent to the TPM.
69 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
70
72 The TCTI or "Transmission Interface" is the communication mechanism
73 with the TPM. TCTIs can be changed for communication with TPMs across
74 different mediums.
75 To control the TCTI, the tools respect:
77 1. The command line option -T or --tcti
79 2. The environment variable: TPM2TOOLS_TCTI.
81 Note: The command line option always overrides the environment vari‐
83 able.
84 The current known TCTIs are:
86 • tabrmd - The resource manager, called tabrmd
88 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
89 abrmd as a tcti name are synonymous.
90 • mssim - Typically used for communicating to the TPM software simula‐
92 tor.
93 • device - Used when talking directly to a TPM device file.
95 • none - Do not initalize a connection with the TPM. Some tools allow
97 for off-tpm options and thus support not using a TCTI. Tools that do
98 not support it will error when attempted to be used without a TCTI
99 connection. Does not support ANY options and MUST BE presented as
100 the exact text of "none".
101 The arguments to either the command line option or the environment
103 variable are in the form:
104 <tcti-name>:<tcti-option-config>
106 Specifying an empty string for either the <tcti-name> or <tcti-op‐
108 tion-config> results in the default being used for that portion respec‐
109 tively.
110 TCTI Defaults
112 When a TCTI is not specified, the default TCTI is searched for using
113 dlopen(3) semantics. The tools will search for tabrmd, device and
114 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
115 what TCTI will be chosen as the default by using the -v option to print
116 the version information. The "default-tcti" key-value pair will indi‐
117 cate which of the aforementioned TCTIs is the default.
118 Custom TCTIs
120 Any TCTI that implements the dynamic TCTI interface can be loaded. The
121 tools internally use dlopen(3), and the raw tcti-name value is used for
122 the lookup. Thus, this could be a path to the shared library, or a li‐
123 brary name as understood by dlopen(3) semantics.
124
126 This collection of options are used to configure the various known TCTI
127 modules available:
128 • device: For the device TCTI, the TPM character device file for use by
130 the device TCTI can be specified. The default is /dev/tpm0.
131 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
133 vice:/dev/tpm0"
134 • mssim: For the mssim TCTI, the domain name or IP address and port
136 number used by the simulator can be specified. The default are
137 127.0.0.1 and 2321.
138 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
140 TI="mssim:host=localhost,port=2321"
141 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
143 ries of simple key value pairs separated by a ',' character. Each
144 key and value string are separated by a '=' character.
145 • TCTI abrmd supports two keys:
147 1. 'bus_name' : The name of the tabrmd service on the bus (a
149 string).
150 2. 'bus_type' : The type of the dbus instance (a string) limited to
152 'session' and 'system'.
153 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
155 ample.FooBar:
156 \--tcti=tabrmd:bus_name=com.example.FooBar
158 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
160 sion:
161 \--tcti:bus_type=session
163 NOTE: abrmd and tabrmd are synonymous.
165 PCR bank specifiers (common/pcr.md)
167
169 Supported hash algorithms are:
170 • 0x4 or sha1 for TPM_ALG_SHA1
172 • 0xB or sha256 for TPM_ALG_SHA256 (default)
174 • 0xC or sha384 for TPM_ALG_SHA384
176 • 0xD or sha512 for TPM_ALG_SHA512
178 • 0x12 or sm3_256 for TPM_ALG_SM3_256
180 NOTE: Your TPM may not support all algorithms.
182
184 Options that take algorithms support "nice-names".
185 There are two major algorithm specification string classes, simple and
187 complex. Only certain algorithms will be accepted by the TPM, based on
188 usage and conditions.
189 Simple specifiers
191 These are strings with no additional specification data. When creating
192 objects, non-specified portions of an object are assumed to defaults.
193 You can find the list of known "Simple Specifiers Below".
194 Asymmetric
196 • rsa
197 • ecc
199 Symmetric
201 • aes
202 • camellia
204 Hashing Algorithms
206 • sha1
207 • sha256
209 • sha384
211 • sha512
213 • sm3_256
215 • sha3_256
217 • sha3_384
219 • sha3_512
221 Keyed Hash
223 • hmac
224 • xor
226 Signing Schemes
228 • rsassa
229 • rsapss
231 • ecdsa
233 • ecdaa
235 • ecschnorr
237 Asymmetric Encryption Schemes
239 • oaep
240 • rsaes
242 • ecdh
244 Modes
246 • ctr
247 • ofb
249 • cbc
251 • cfb
253 • ecb
255 Misc
257 • null
258 Complex Specifiers
260 Objects, when specified for creation by the TPM, have numerous algo‐
261 rithms to populate in the public data. Things like type, scheme and
262 asymmetric details, key size, etc. Below is the general format for
263 specifying this data: <type>:<scheme>:<symmetric-details>
264 Type Specifiers
266 This portion of the complex algorithm specifier is required. The re‐
267 maining scheme and symmetric details will default based on the type
268 specified and the type of the object being created.
269 • aes - Default AES: aes128
271 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
273 If mode is not specified, defaults to null.
274 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
276 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
278 • ecc - Elliptical Curve, defaults to ecc256.
280 • ecc192 - 192 bit ECC
282 • ecc224 - 224 bit ECC
284 • ecc256 - 256 bit ECC
286 • ecc384 - 384 bit ECC
288 • ecc521 - 521 bit ECC
290 • rsa - Default RSA: rsa2048
292 • rsa1024 - RSA with 1024 bit keysize.
294 • rsa2048 - RSA with 2048 bit keysize.
296 • rsa4096 - RSA with 4096 bit keysize.
298 Scheme Specifiers
300 Next, is an optional field, it can be skipped.
301 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
303 Most signing schemes take a hash algorithm directly following the sign‐
304 ing scheme. If the hash algorithm is missing, it defaults to sha256.
305 Some take no arguments, and some take multiple arguments.
306 Hash Optional Scheme Specifiers
308 These scheme specifiers are followed by a dash and a valid hash algo‐
309 rithm, For example: oaep-sha256.
310 • oaep
312 • ecdh
314 • rsassa
316 • rsapss
318 • ecdsa
320 • ecschnorr
322 Multiple Option Scheme Specifiers
324 This scheme specifier is followed by a count (max size UINT16) then
325 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
326 ecdaa4-sha256. If no count is specified, it defaults to 4.
327 No Option Scheme Specifiers
329 This scheme specifier takes NO arguments. * rsaes
330 Symmetric Details Specifiers
332 This field is optional, and defaults based on the type of object being
333 created and it's attributes. Generally, any valid Symmetric specifier
334 from the Type Specifiers list should work. If not specified, an asym‐
335 metric objects symmetric details defaults to aes128cfb.
336 Examples
338 Create an rsa2048 key with an rsaes asymmetric encryption scheme
339 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
340 Create an ecc256 key with an ecdaa signing scheme with a count of 4
342 and sha384 hash
343 /tpm2_create -C parent.ctx -G ecc256:ec‐
345 daa4-sha384 -u key.pub -r key.priv
346
348 Display all PCR values
349 tpm2_pcrread
350 Display the PCR values with a specified bank
352 tpm2_pcrread sha1
353 Display the PCR values with specified banks and store in a file
355 tpm2_pcrread -o pcrs sha1:16,17,18+sha256:16,17,18
356 Display the supported PCR bank algorithms and exit
358 tpm2_pcrread
359
361 The maximum number of PCR that can be dumped at once is associated with
362 the maximum length of a bank.
363 On most TPMs, it means that this tool can dump up to 24 PCRs at once.
365
367 Tools can return any of the following codes:
368 • 0 - Success.
370 • 1 - General non-specific error.
372 • 2 - Options handling error.
374 • 3 - Authentication error.
376 • 4 - TCTI related error.
378 • 5 - Non supported scheme. Applicable to tpm2_testparams.
380
382 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
383
385 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
386tpm2-tools tpm2_pcrread(1)