1tpm2_flushcontext(1) General Commands Manual tpm2_flushcontext(1)
2
6 tpm2_flushcontext(1) - Remove a specified handle, or all contexts asso‐
7 ciated with a transient object, loaded session or saved session from
8 the TPM.
9
11 tpm2_flushcontext [OPTIONS] [ARGUMENT]
12
14 tpm2_flushcontext(1) - Remove a specified handle, or all contexts asso‐
15 ciated with a transient object, loaded session or saved session from
16 the TPM. The object to be flushed is specified as the first argument
17 to the tool and is in one of the following forms: - The handle of the
18 object to be flushed from the TPM. Must be a valid handle number. -
19 Flush a session via a session file. A session file is generated from
20 tpm2_startauthsession(1)’s -S option.
21
23 • -t, --transient-object:
24 Remove all transient objects.
26 • -l, --loaded-session:
28 Remove all loaded sessions.
30 • -s, --saved-session:
32 Remove all saved sessions.
34 • ARGUMENT the command line argument specifies the OBJECT to be removed
36 from the TPM resident memory.
37 • --cphash=FILE
39 File path to record the hash of the command parameters. This is com‐
41 monly termed as cpHash. NOTE: When this option is selected, The tool
42 will not actually execute the command, it simply returns a cpHash.
43
45 This collection of options are common to many programs and provide in‐
46 formation that many users may expect.
47 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
49 attempts to invoke the manpager for the tool, however, on failure
50 will output a short tool summary. This is the same behavior if the
51 “man” option argument is specified, however if explicit “man” is re‐
52 quested, the tool will provide errors from man on stderr. If the
53 “no-man” option if specified, or the manpager fails, the short op‐
54 tions will be output to stdout.
55 To successfully use the manpages feature requires the manpages to be
57 installed or on MANPATH, See man(1) for more details.
58 • -v, --version: Display version information for this tool, supported
60 tctis and exit.
61 • -V, --verbose: Increase the information that the tool prints to the
63 console during its execution. When using this option the file and
64 line number are printed.
65 • -Q, --quiet: Silence normal tool output to stdout.
67 • -Z, --enable-errata: Enable the application of errata fixups. Useful
69 if an errata fixup needs to be applied to commands sent to the TPM.
70 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
71
73 The TCTI or “Transmission Interface” is the communication mechanism
74 with the TPM. TCTIs can be changed for communication with TPMs across
75 different mediums.
76 To control the TCTI, the tools respect:
78 1. The command line option -T or --tcti
80 2. The environment variable: TPM2TOOLS_TCTI.
82 Note: The command line option always overrides the environment vari‐
84 able.
85 The current known TCTIs are:
87 • tabrmd - The resource manager, called tabrmd
89 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
90 abrmd as a tcti name are synonymous.
91 • mssim - Typically used for communicating to the TPM software simula‐
93 tor.
94 • device - Used when talking directly to a TPM device file.
96 • none - Do not initalize a connection with the TPM. Some tools allow
98 for off-tpm options and thus support not using a TCTI. Tools that do
99 not support it will error when attempted to be used without a TCTI
100 connection. Does not support ANY options and MUST BE presented as
101 the exact text of “none”.
102 The arguments to either the command line option or the environment
104 variable are in the form:
105 <tcti-name>:<tcti-option-config>
107 Specifying an empty string for either the <tcti-name> or <tcti-op‐
109 tion-config> results in the default being used for that portion respec‐
110 tively.
111 TCTI Defaults
113 When a TCTI is not specified, the default TCTI is searched for using
114 dlopen(3) semantics. The tools will search for tabrmd, device and
115 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
116 what TCTI will be chosen as the default by using the -v option to print
117 the version information. The “default-tcti” key-value pair will indi‐
118 cate which of the aforementioned TCTIs is the default.
119 Custom TCTIs
121 Any TCTI that implements the dynamic TCTI interface can be loaded. The
122 tools internally use dlopen(3), and the raw tcti-name value is used for
123 the lookup. Thus, this could be a path to the shared library, or a li‐
124 brary name as understood by dlopen(3) semantics.
125
127 This collection of options are used to configure the various known TCTI
128 modules available:
129 • device: For the device TCTI, the TPM character device file for use by
131 the device TCTI can be specified. The default is /dev/tpm0.
132 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
134 vice:/dev/tpm0”
135 • mssim: For the mssim TCTI, the domain name or IP address and port
137 number used by the simulator can be specified. The default are
138 127.0.0.1 and 2321.
139 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
141 TI=“mssim:host=localhost,port=2321”
142 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
144 ries of simple key value pairs separated by a `,' character. Each
145 key and value string are separated by a `=' character.
146 • TCTI abrmd supports two keys:
148 1. `bus_name' : The name of the tabrmd service on the bus (a
150 string).
151 2. `bus_type' : The type of the dbus instance (a string) limited to
153 `session' and `system'.
154 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
156 ample.FooBar:
157 \--tcti=tabrmd:bus_name=com.example.FooBar
159 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
161 sion:
162 \--tcti:bus_type=session
164 NOTE: abrmd and tabrmd are synonymous.
166
168 Flushing a Transient Object
169 Typically, when using the TPM, the interactions occur through a re‐
170 source manager, like tpm2-abrmd(8). When the process exits, transient
171 object handles are flushed. Thus, flushing transient objects through
172 the command line is not required. However, when interacting with the
173 TPM directly, this scenario is possible. The below example assumes di‐
174 rect TPM access not brokered by a resource manager. Specifically we
175 will use the simulator.
176 tpm2_createprimary -Tmssim -c primary.ctx
178 tpm2_getcap -T mssim handles-transient
180 - 0x80000000
181 tpm2_flushcontext -T mssim 0x80000000
183 Flush All the Transient Objects
185 tpm2_flushcontext \--transient-object
186 Flush a Session
188 tpm2_startauthsession -S session.dat
189 tpm2_flushcontext session.dat
191
193 Tools can return any of the following codes:
194 • 0 - Success.
196 • 1 - General non-specific error.
198 • 2 - Options handling error.
200 • 3 - Authentication error.
202 • 4 - TCTI related error.
204 • 5 - Non supported scheme. Applicable to tpm2_testparams.
206
208 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
209
211 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
212 fo/tpm2)
213tpm2-tools tpm2_flushcontext(1)