1tpm2_pcrreset(1) General Commands Manual tpm2_pcrreset(1)
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6 tpm2_pcrreset(1) - Reset one or more PCR banks
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9 tpm2_pcrreset [OPTIONS] PCR_INDEX ...
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12 tpm2_pcrreset(1) - Reset PCR value in all banks for specified index.
13 More than one PCR index can be specified.
14 The reset value is manufacturer-dependent and is either sequence of 00
16 or FF on the length of the hash algorithm for each supported bank.
17 PCR_INDEX is a space separated list of PCR indexes to be reset when is‐
19 suing the command.
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22 This tool accepts no tool specific options.
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25 This collection of options are common to many programs and provide in‐
26 formation that many users may expect.
27 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
29 attempts to invoke the manpager for the tool, however, on failure
30 will output a short tool summary. This is the same behavior if the
31 "man" option argument is specified, however if explicit "man" is re‐
32 quested, the tool will provide errors from man on stderr. If the
33 "no-man" option if specified, or the manpager fails, the short op‐
34 tions will be output to stdout.
35 To successfully use the manpages feature requires the manpages to be
37 installed or on MANPATH, See man(1) for more details.
38 · -v, --version: Display version information for this tool, supported
40 tctis and exit.
41 · -V, --verbose: Increase the information that the tool prints to the
43 console during its execution. When using this option the file and
44 line number are printed.
45 · -Q, --quiet: Silence normal tool output to stdout.
47 · -Z, --enable-errata: Enable the application of errata fixups. Useful
49 if an errata fixup needs to be applied to commands sent to the TPM.
50 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
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53 The TCTI or "Transmission Interface" is the communication mechanism
54 with the TPM. TCTIs can be changed for communication with TPMs across
55 different mediums.
56 To control the TCTI, the tools respect:
58 1. The command line option -T or --tcti
60 2. The environment variable: TPM2TOOLS_TCTI.
62 Note: The command line option always overrides the environment vari‐
64 able.
65 The current known TCTIs are:
67 · tabrmd - The resource manager, called tabrmd
69 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
70 abrmd as a tcti name are synonymous.
71 · mssim - Typically used for communicating to the TPM software simula‐
73 tor.
74 · device - Used when talking directly to a TPM device file.
76 · none - Do not initalize a connection with the TPM. Some tools allow
78 for off-tpm options and thus support not using a TCTI. Tools that do
79 not support it will error when attempted to be used without a TCTI
80 connection. Does not support ANY options and MUST BE presented as
81 the exact text of "none".
82 The arguments to either the command line option or the environment
84 variable are in the form:
85 <tcti-name>:<tcti-option-config>
87 Specifying an empty string for either the <tcti-name> or <tcti-op‐
89 tion-config> results in the default being used for that portion respec‐
90 tively.
91 TCTI Defaults
93 When a TCTI is not specified, the default TCTI is searched for using
94 dlopen(3) semantics. The tools will search for tabrmd, device and
95 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
96 what TCTI will be chosen as the default by using the -v option to print
97 the version information. The "default-tcti" key-value pair will indi‐
98 cate which of the aforementioned TCTIs is the default.
99 Custom TCTIs
101 Any TCTI that implements the dynamic TCTI interface can be loaded. The
102 tools internally use dlopen(3), and the raw tcti-name value is used for
103 the lookup. Thus, this could be a path to the shared library, or a li‐
104 brary name as understood by dlopen(3) semantics.
105
107 This collection of options are used to configure the various known TCTI
108 modules available:
109 · device: For the device TCTI, the TPM character device file for use by
111 the device TCTI can be specified. The default is /dev/tpm0.
112 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
114 vice:/dev/tpm0"
115 · mssim: For the mssim TCTI, the domain name or IP address and port
117 number used by the simulator can be specified. The default are
118 127.0.0.1 and 2321.
119 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
121 TI="mssim:host=localhost,port=2321"
122 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
124 ries of simple key value pairs separated by a ',' character. Each
125 key and value string are separated by a '=' character.
126 · TCTI abrmd supports two keys:
128 1. 'bus_name' : The name of the tabrmd service on the bus (a
130 string).
131 2. 'bus_type' : The type of the dbus instance (a string) limited to
133 'session' and 'system'.
134 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
136 ample.FooBar:
137 \--tcti=tabrmd:bus_name=com.example.FooBar
139 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
141 sion:
142 \--tcti:bus_type=session
144 NOTE: abrmd and tabrmd are synonymous.
146
148 Reset a single PCR
149 tpm2_pcrreset 23
150 Reset multiple PCRs
152 tpm2_pcrreset 16 23
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155 On operating system's locality (generally locality 0), only PCR 23 can
156 be reset. PCR-16 can also be reset on this locality, depending on TPM
157 manufacturers which could define this PCR as resettable.
158 PCR 0 to 15 are not resettable (being part of SRTM). PCR 16 to 22 are
160 mostly reserved for DRTM or dedicated to specific localities and might
161 not be resettable depending on current TPM locality.
162
164 Tools can return any of the following codes:
165 · 0 - Success.
167 · 1 - General non-specific error.
169 · 2 - Options handling error.
171 · 3 - Authentication error.
173 · 4 - TCTI related error.
175 · 5 - Non supported scheme. Applicable to tpm2_testparams.
177
179 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
180
182 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
183tpm2-tools tpm2_pcrreset(1)