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 • -F, --pcrs_format=FORMAT:
44 Format selection for the binary blob in the PCR output file. `val‐
46 ues' will output a binary blob of the PCR values. `serialized' will
47 output a binary blob of the PCR values in the form of serialized data
48 structure in little endian format. Optional. Default is `values'.
49
51 This collection of options are common to many programs and provide in‐
52 formation that many users may expect.
53 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
55 attempts to invoke the manpager for the tool, however, on failure
56 will output a short tool summary. This is the same behavior if the
57 “man” option argument is specified, however if explicit “man” is re‐
58 quested, the tool will provide errors from man on stderr. If the
59 “no-man” option if specified, or the manpager fails, the short op‐
60 tions will be output to stdout.
61 To successfully use the manpages feature requires the manpages to be
63 installed or on MANPATH, See man(1) for more details.
64 • -v, --version: Display version information for this tool, supported
66 tctis and exit.
67 • -V, --verbose: Increase the information that the tool prints to the
69 console during its execution. When using this option the file and
70 line number are printed.
71 • -Q, --quiet: Silence normal tool output to stdout.
73 • -Z, --enable-errata: Enable the application of errata fixups. Useful
75 if an errata fixup needs to be applied to commands sent to the TPM.
76 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
77
79 The TCTI or “Transmission Interface” is the communication mechanism
80 with the TPM. TCTIs can be changed for communication with TPMs across
81 different mediums.
82 To control the TCTI, the tools respect:
84 1. The command line option -T or --tcti
86 2. The environment variable: TPM2TOOLS_TCTI.
88 Note: The command line option always overrides the environment vari‐
90 able.
91 The current known TCTIs are:
93 • tabrmd - The resource manager, called tabrmd
95 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
96 abrmd as a tcti name are synonymous.
97 • mssim - Typically used for communicating to the TPM software simula‐
99 tor.
100 • device - Used when talking directly to a TPM device file.
102 • none - Do not initalize a connection with the TPM. Some tools allow
104 for off-tpm options and thus support not using a TCTI. Tools that do
105 not support it will error when attempted to be used without a TCTI
106 connection. Does not support ANY options and MUST BE presented as
107 the exact text of “none”.
108 The arguments to either the command line option or the environment
110 variable are in the form:
111 <tcti-name>:<tcti-option-config>
113 Specifying an empty string for either the <tcti-name> or <tcti-op‐
115 tion-config> results in the default being used for that portion respec‐
116 tively.
117 TCTI Defaults
119 When a TCTI is not specified, the default TCTI is searched for using
120 dlopen(3) semantics. The tools will search for tabrmd, device and
121 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
122 what TCTI will be chosen as the default by using the -v option to print
123 the version information. The “default-tcti” key-value pair will indi‐
124 cate which of the aforementioned TCTIs is the default.
125 Custom TCTIs
127 Any TCTI that implements the dynamic TCTI interface can be loaded. The
128 tools internally use dlopen(3), and the raw tcti-name value is used for
129 the lookup. Thus, this could be a path to the shared library, or a li‐
130 brary name as understood by dlopen(3) semantics.
131
133 This collection of options are used to configure the various known TCTI
134 modules available:
135 • device: For the device TCTI, the TPM character device file for use by
137 the device TCTI can be specified. The default is /dev/tpm0.
138 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
140 vice:/dev/tpm0”
141 • mssim: For the mssim TCTI, the domain name or IP address and port
143 number used by the simulator can be specified. The default are
144 127.0.0.1 and 2321.
145 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
147 TI=“mssim:host=localhost,port=2321”
148 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
150 ries of simple key value pairs separated by a `,' character. Each
151 key and value string are separated by a `=' character.
152 • TCTI abrmd supports two keys:
154 1. `bus_name' : The name of the tabrmd service on the bus (a
156 string).
157 2. `bus_type' : The type of the dbus instance (a string) limited to
159 `session' and `system'.
160 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
162 ample.FooBar:
163 \--tcti=tabrmd:bus_name=com.example.FooBar
165 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
167 sion:
168 \--tcti:bus_type=session
170 NOTE: abrmd and tabrmd are synonymous.
172 PCR bank specifiers (common/pcr.md)
174
176 Supported hash algorithms are:
177 • 0x4 or sha1 for TPM_ALG_SHA1
179 • 0xB or sha256 for TPM_ALG_SHA256 (default)
181 • 0xC or sha384 for TPM_ALG_SHA384
183 • 0xD or sha512 for TPM_ALG_SHA512
185 • 0x12 or sm3_256 for TPM_ALG_SM3_256
187 NOTE: Your TPM may not support all algorithms.
189
191 Options that take algorithms support “nice-names”.
192 There are two major algorithm specification string classes, simple and
194 complex. Only certain algorithms will be accepted by the TPM, based on
195 usage and conditions.
196 Simple specifiers
198 These are strings with no additional specification data. When creating
199 objects, non-specified portions of an object are assumed to defaults.
200 You can find the list of known “Simple Specifiers Below”.
201 Asymmetric
203 • rsa
204 • ecc
206 Symmetric
208 • aes
209 • camellia
211 Hashing Algorithms
213 • sha1
214 • sha256
216 • sha384
218 • sha512
220 • sm3_256
222 • sha3_256
224 • sha3_384
226 • sha3_512
228 Keyed Hash
230 • hmac
231 • xor
233 Signing Schemes
235 • rsassa
236 • rsapss
238 • ecdsa
240 • ecdaa
242 • ecschnorr
244 Asymmetric Encryption Schemes
246 • oaep
247 • rsaes
249 • ecdh
251 Modes
253 • ctr
254 • ofb
256 • cbc
258 • cfb
260 • ecb
262 Misc
264 • null
265 Complex Specifiers
267 Objects, when specified for creation by the TPM, have numerous algo‐
268 rithms to populate in the public data. Things like type, scheme and
269 asymmetric details, key size, etc. Below is the general format for
270 specifying this data: <type>:<scheme>:<symmetric-details>
271 Type Specifiers
273 This portion of the complex algorithm specifier is required. The re‐
274 maining scheme and symmetric details will default based on the type
275 specified and the type of the object being created.
276 • aes - Default AES: aes128
278 • aes128<mode> - 128 bit AES with optional mode (ctr|ofb|cbc|cfb|ecb).
280 If mode is not specified, defaults to null.
281 • aes192<mode> - Same as aes128<mode>, except for a 192 bit key size.
283 • aes256<mode> - Same as aes128<mode>, except for a 256 bit key size.
285 • ecc - Elliptical Curve, defaults to ecc256.
287 • ecc192 - 192 bit ECC
289 • ecc224 - 224 bit ECC
291 • ecc256 - 256 bit ECC
293 • ecc384 - 384 bit ECC
295 • ecc521 - 521 bit ECC
297 • rsa - Default RSA: rsa2048
299 • rsa1024 - RSA with 1024 bit keysize.
301 • rsa2048 - RSA with 2048 bit keysize.
303 • rsa4096 - RSA with 4096 bit keysize.
305 Scheme Specifiers
307 Next, is an optional field, it can be skipped.
308 Schemes are usually Signing Schemes or Asymmetric Encryption Schemes.
310 Most signing schemes take a hash algorithm directly following the sign‐
311 ing scheme. If the hash algorithm is missing, it defaults to sha256.
312 Some take no arguments, and some take multiple arguments.
313 Hash Optional Scheme Specifiers
315 These scheme specifiers are followed by a dash and a valid hash algo‐
316 rithm, For example: oaep-sha256.
317 • oaep
319 • ecdh
321 • rsassa
323 • rsapss
325 • ecdsa
327 • ecschnorr
329 Multiple Option Scheme Specifiers
331 This scheme specifier is followed by a count (max size UINT16) then
332 followed by a dash(-) and a valid hash algorithm. * ecdaa For example,
333 ecdaa4-sha256. If no count is specified, it defaults to 4.
334 No Option Scheme Specifiers
336 This scheme specifier takes NO arguments. * rsaes
337 Symmetric Details Specifiers
339 This field is optional, and defaults based on the type of object being
340 created and it’s attributes. Generally, any valid Symmetric specifier
341 from the Type Specifiers list should work. If not specified, an asym‐
342 metric objects symmetric details defaults to aes128cfb.
343 Examples
345 Create an rsa2048 key with an rsaes asymmetric encryption scheme
346 tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
347 Create an ecc256 key with an ecdaa signing scheme with a count of 4 and
349 sha384 hash
350 /tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r
351 key.priv
352
354 Display all PCR values
355 tpm2_pcrread
356 Display the PCR values with a specified bank
358 tpm2_pcrread sha1
359 Display the PCR values with specified banks and store in a file
361 tpm2_pcrread -o pcrs sha1:16,17,18+sha256:16,17,18
362 Display the supported PCR bank algorithms and exit
364 tpm2_pcrread
365
367 The maximum number of PCR that can be dumped at once is associated with
368 the maximum length of a bank.
369 On most TPMs, it means that this tool can dump up to 24 PCRs at once.
371
373 Tools can return any of the following codes:
374 • 0 - Success.
376 • 1 - General non-specific error.
378 • 2 - Options handling error.
380 • 3 - Authentication error.
382 • 4 - TCTI related error.
384 • 5 - Non supported scheme. Applicable to tpm2_testparams.
386
388 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
389
391 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
392tpm2-tools tpm2_pcrread(1)