1tpm2_getcap(1) General Commands Manual tpm2_getcap(1)
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6 tpm2_getcap(1) - Display TPM capabilities in a human readable form.
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9 tpm2_getcap [OPTIONS] [CAPABILITY]
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12 tpm2_getcap(1) - Query the TPM for it’s capabilities / properties and
13 print them to the console. It takes a string form of the capability to
14 query as an argument to the tool. Currently supported capability
15 groups are:
16 • algorithms: Display data about supported algorithms.
18 • commands: Display data about supported commands.
20 • pcrs: Display currently allocated PCRs.
22 • properties-fixed: Display fixed TPM properties.
24 • properties-variable: Display variable TPM properties.
26 • ecc-curves: Display data about elliptic curves.
28 • handles-transient: Display handles about transient objects.
30 • handles-persistent: Display handles about persistent objects.
32 • handles-permanent: Display handles about permanent objects.
34 • handles-pcr: Display handles about PCRs.
36 • handles-nv-index: Display handles about NV Indices.
38 • handles-loaded-session: Display handles about both loaded HMAC and
40 policy sessions.
41 • handles-saved-session: Display handles about saved sessions.
43 • vendor[:num]: Displays the vendor properties as a hex buffer output.
45 The string “vendor” can be suffixed with a colon followed by a number
46 as understood by strtoul(3) with a 0 base. That value is used as the
47 property value within the
48 TPM2_GetCapability command, and defaults to 1. An example to call it
49 with a property value of 2 is: tpm2_getcap vendor:2
50 NOTE: if vendor requests hang, try the “-i” option to ignore the
52 moreData field and only read once.
53
55 • -l, --list:
56 List known supported capability names. These names can be supplied
58 as the argument to the -c option. Output is in a YAML compliant list
59 to stdout.
60 For example:
62 - algorithms
64 - commands
65 - properties-fixed
66 ...
67 • --ignore-moredata
69 Ignores the moreData field when dealing with buggy TPM responses.
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73 This collection of options are common to many programs and provide in‐
74 formation that many users may expect.
75 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
77 attempts to invoke the manpager for the tool, however, on failure
78 will output a short tool summary. This is the same behavior if the
79 “man” option argument is specified, however if explicit “man” is re‐
80 quested, the tool will provide errors from man on stderr. If the
81 “no-man” option if specified, or the manpager fails, the short op‐
82 tions will be output to stdout.
83 To successfully use the manpages feature requires the manpages to be
85 installed or on MANPATH, See man(1) for more details.
86 • -v, --version: Display version information for this tool, supported
88 tctis and exit.
89 • -V, --verbose: Increase the information that the tool prints to the
91 console during its execution. When using this option the file and
92 line number are printed.
93 • -Q, --quiet: Silence normal tool output to stdout.
95 • -Z, --enable-errata: Enable the application of errata fixups. Useful
97 if an errata fixup needs to be applied to commands sent to the TPM.
98 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
99
101 The TCTI or “Transmission Interface” is the communication mechanism
102 with the TPM. TCTIs can be changed for communication with TPMs across
103 different mediums.
104 To control the TCTI, the tools respect:
106 1. The command line option -T or --tcti
108 2. The environment variable: TPM2TOOLS_TCTI.
110 Note: The command line option always overrides the environment vari‐
112 able.
113 The current known TCTIs are:
115 • tabrmd - The resource manager, called tabrmd
117 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
118 abrmd as a tcti name are synonymous.
119 • mssim - Typically used for communicating to the TPM software simula‐
121 tor.
122 • device - Used when talking directly to a TPM device file.
124 • none - Do not initalize a connection with the TPM. Some tools allow
126 for off-tpm options and thus support not using a TCTI. Tools that do
127 not support it will error when attempted to be used without a TCTI
128 connection. Does not support ANY options and MUST BE presented as
129 the exact text of “none”.
130 The arguments to either the command line option or the environment
132 variable are in the form:
133 <tcti-name>:<tcti-option-config>
135 Specifying an empty string for either the <tcti-name> or <tcti-op‐
137 tion-config> results in the default being used for that portion respec‐
138 tively.
139 TCTI Defaults
141 When a TCTI is not specified, the default TCTI is searched for using
142 dlopen(3) semantics. The tools will search for tabrmd, device and
143 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
144 what TCTI will be chosen as the default by using the -v option to print
145 the version information. The “default-tcti” key-value pair will indi‐
146 cate which of the aforementioned TCTIs is the default.
147 Custom TCTIs
149 Any TCTI that implements the dynamic TCTI interface can be loaded. The
150 tools internally use dlopen(3), and the raw tcti-name value is used for
151 the lookup. Thus, this could be a path to the shared library, or a li‐
152 brary name as understood by dlopen(3) semantics.
153
155 This collection of options are used to configure the various known TCTI
156 modules available:
157 • device: For the device TCTI, the TPM character device file for use by
159 the device TCTI can be specified. The default is /dev/tpm0.
160 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
162 vice:/dev/tpm0”
163 • mssim: For the mssim TCTI, the domain name or IP address and port
165 number used by the simulator can be specified. The default are
166 127.0.0.1 and 2321.
167 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
169 TI=“mssim:host=localhost,port=2321”
170 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
172 ries of simple key value pairs separated by a `,' character. Each
173 key and value string are separated by a `=' character.
174 • TCTI abrmd supports two keys:
176 1. `bus_name' : The name of the tabrmd service on the bus (a
178 string).
179 2. `bus_type' : The type of the dbus instance (a string) limited to
181 `session' and `system'.
182 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
184 ample.FooBar:
185 \--tcti=tabrmd:bus_name=com.example.FooBar
187 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
189 sion:
190 \--tcti:bus_type=session
192 NOTE: abrmd and tabrmd are synonymous.
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196 To list the fixed properties of the TPM
197 tpm2_getcap properties-fixed
198 To list the supported capability groups
200 tpm2_getcap -l
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203 Tools can return any of the following codes:
204 • 0 - Success.
206 • 1 - General non-specific error.
208 • 2 - Options handling error.
210 • 3 - Authentication error.
212 • 4 - TCTI related error.
214 • 5 - Non supported scheme. Applicable to tpm2_testparams.
216
218 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
219
221 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
222 fo/tpm2)
223tpm2-tools tpm2_getcap(1)