1tpm2_nvwrite(1) General Commands Manual tpm2_nvwrite(1)
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6 tpm2_nvwrite(1) - Write data to a Non-Volatile (NV) index.
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9 tpm2_nvwrite [OPTIONS] [ARGUMENT]
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12 tpm2_nvwrite(1) - Write data specified via FILE to a Non-Volatile (NV)
13 index. If FILE is not specified, it defaults to stdin. The index can
14 be specified as raw handle or an offset value to the nv handle range
15 "TPM2_HR_NV_INDEX".
16
18 · -i, --input=FILE:
19 Specifies the input file with data to write to NV.
21 · -C, --hierarchy=OBJECT:
23 Specifies the hierarchy used to authorize. Supported options are:
24 · o for TPM_RH_OWNER
26 · p for TPM_RH_PLATFORM
28 · <num> where a hierarchy handle or nv-index may be used.
30 When -C isn't explicitly passed the index handle will be used to au‐
32 thorize against the index. The index auth value is set via the -p
33 option to tpm2_nvdefine(1).
34 · -P, --auth=AUTH:
36 Specifies the authorization value for the hierarchy.
38 · --offset=NATURAL_NUMBER:
40 The offset within the NV index to start writing at.
42 · --cphash=FILE
44 File path to record the hash of the command parameters. This is com‐
46 monly termed as cpHash. NOTE: When this option is selected, The tool
47 will not actually execute the command, it simply returns a cpHash.
48 References
51 The type of a context object, whether it is a handle or file name, is
52 determined according to the following logic in-order:
53 · If the argument is a file path, then the file is loaded as a restored
55 TPM transient object.
56 · If the argument is a prefix match on one of:
58 · owner: the owner hierarchy
60 · platform: the platform hierarchy
62 · endorsement: the endorsement hierarchy
64 · lockout: the lockout control persistent object
66 · If the argument argument can be loaded as a number it will be treat
68 as a handle, e.g. 0x81010013 and used directly.OBJECT.
69
71 Authorization for use of an object in TPM2.0 can come in 3 different
72 forms: 1. Password 2. HMAC 3. Sessions
73 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
75 fied".
76 Passwords
78 Passwords are interpreted in the following forms below using prefix
79 identifiers.
80 Note: By default passwords are assumed to be in the string form when
82 they do not have a prefix.
83 String
85 A string password, specified by prefix "str:" or it's absence (raw
86 string without prefix) is not interpreted, and is directly used for au‐
87 thorization.
88 Examples
90 foobar
91 str:foobar
92 Hex-string
94 A hex-string password, specified by prefix "hex:" is converted from a
95 hexidecimal form into a byte array form, thus allowing passwords with
96 non-printable and/or terminal un-friendly characters.
97 Example
99 hex:0x1122334455667788
100 File
102 A file based password, specified be prefix "file:" should be the path
103 of a file containing the password to be read by the tool or a "-" to
104 use stdin. Storing passwords in files prevents information leakage,
105 passwords passed as options can be read from the process list or common
106 shell history features.
107 Examples
109 # to use stdin and be prompted
110 file:-
111 # to use a file from a path
113 file:path/to/password/file
114 # to echo a password via stdin:
116 echo foobar | tpm2_tool -p file:-
117 # to use a bash here-string via stdin:
119 tpm2_tool -p file:- <<< foobar
121 Sessions
123 When using a policy session to authorize the use of an object, prefix
124 the option argument with the session keyword. Then indicate a path to
125 a session file that was created with tpm2_startauthsession(1). Option‐
126 ally, if the session requires an auth value to be sent with the session
127 handle (eg policy password), then append a + and a string as described
128 in the Passwords section.
129 Examples
131 To use a session context file called session.ctx.
132 session:session.ctx
134 To use a session context file called session.ctx AND send the authvalue
136 mypassword.
137 session:session.ctx+mypassword
139 To use a session context file called session.ctx AND send the HEX auth‐
141 value 0x11223344.
142 session:session.ctx+hex:11223344
144 PCR Authorizations
146 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
147 language. The PCR minilanguage is as follows:
148 <pcr-spec>=<raw-pcr-file>
149 The PCR spec is documented in in the section "PCR bank specifiers".
151 The raw-pcr-file is an optional the output of the raw PCR contents as
153 returned by tpm2_pcrread(1).
154 PCR bank specifiers (common/pcr.md)
156 Examples
158 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
159 er of:
160 pcr:sha256:0,1,2,3
162 specifying AUTH.
164
166 This collection of options are common to many programs and provide in‐
167 formation that many users may expect.
168 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
170 attempts to invoke the manpager for the tool, however, on failure
171 will output a short tool summary. This is the same behavior if the
172 "man" option argument is specified, however if explicit "man" is re‐
173 quested, the tool will provide errors from man on stderr. If the
174 "no-man" option if specified, or the manpager fails, the short op‐
175 tions will be output to stdout.
176 To successfully use the manpages feature requires the manpages to be
178 installed or on MANPATH, See man(1) for more details.
179 · -v, --version: Display version information for this tool, supported
181 tctis and exit.
182 · -V, --verbose: Increase the information that the tool prints to the
184 console during its execution. When using this option the file and
185 line number are printed.
186 · -Q, --quiet: Silence normal tool output to stdout.
188 · -Z, --enable-errata: Enable the application of errata fixups. Useful
190 if an errata fixup needs to be applied to commands sent to the TPM.
191 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
192 formation many users may expect.
193
195 The TCTI or "Transmission Interface" is the communication mechanism
196 with the TPM. TCTIs can be changed for communication with TPMs across
197 different mediums.
198 To control the TCTI, the tools respect:
200 1. The command line option -T or --tcti
202 2. The environment variable: TPM2TOOLS_TCTI.
204 Note: The command line option always overrides the environment vari‐
206 able.
207 The current known TCTIs are:
209 · tabrmd - The resource manager, called tabrmd
211 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
212 abrmd as a tcti name are synonymous.
213 · mssim - Typically used for communicating to the TPM software simula‐
215 tor.
216 · device - Used when talking directly to a TPM device file.
218 · none - Do not initalize a connection with the TPM. Some tools allow
220 for off-tpm options and thus support not using a TCTI. Tools that do
221 not support it will error when attempted to be used without a TCTI
222 connection. Does not support ANY options and MUST BE presented as
223 the exact text of "none".
224 The arguments to either the command line option or the environment
226 variable are in the form:
227 <tcti-name>:<tcti-option-config>
229 Specifying an empty string for either the <tcti-name> or <tcti-op‐
231 tion-config> results in the default being used for that portion respec‐
232 tively.
233 TCTI Defaults
235 When a TCTI is not specified, the default TCTI is searched for using
236 dlopen(3) semantics. The tools will search for tabrmd, device and
237 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
238 what TCTI will be chosen as the default by using the -v option to print
239 the version information. The "default-tcti" key-value pair will indi‐
240 cate which of the aforementioned TCTIs is the default.
241 Custom TCTIs
243 Any TCTI that implements the dynamic TCTI interface can be loaded. The
244 tools internally use dlopen(3), and the raw tcti-name value is used for
245 the lookup. Thus, this could be a path to the shared library, or a li‐
246 brary name as understood by dlopen(3) semantics.
247
249 This collection of options are used to configure the various known TCTI
250 modules available:
251 · device: For the device TCTI, the TPM character device file for use by
253 the device TCTI can be specified. The default is /dev/tpm0.
254 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
256 vice:/dev/tpm0"
257 · mssim: For the mssim TCTI, the domain name or IP address and port
259 number used by the simulator can be specified. The default are
260 127.0.0.1 and 2321.
261 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
263 TI="mssim:host=localhost,port=2321"
264 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
266 ries of simple key value pairs separated by a ',' character. Each
267 key and value string are separated by a '=' character.
268 · TCTI abrmd supports two keys:
270 1. 'bus_name' : The name of the tabrmd service on the bus (a
272 string).
273 2. 'bus_type' : The type of the dbus instance (a string) limited to
275 'session' and 'system'.
276 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
278 ample.FooBar:
279 \--tcti=tabrmd:bus_name=com.example.FooBar
281 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
283 sion:
284 \--tcti:bus_type=session
286 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
288 ules.
289
291 Write the file nv.data to index 0x01000001
292 tpm2_nvdefine -Q 1 -C o -s 32 -a "ownerread|policywrite|ownerwrite"
293 echo "please123abc" > nv.test_w
295 tpm2_nvwrite -Q 1 -C o -i nv.test_w
297
299 Tools can return any of the following codes:
300 · 0 - Success.
302 · 1 - General non-specific error.
304 · 2 - Options handling error.
306 · 3 - Authentication error.
308 · 4 - TCTI related error.
310 · 5 - Non supported scheme. Applicable to tpm2_testparams.
312
314 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
315
317 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
318tpm2-tools tpm2_nvwrite(1)