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 References
45 The type of a context object, whether it is a handle or file name, is
46 determined according to the following logic in-order:
47 · If the argument is a file path, then the file is loaded as a restored
49 TPM transient object.
50 · If the argument is a prefix match on one of:
52 · owner: the owner hierarchy
54 · platform: the platform hierarchy
56 · endorsement: the endorsement hierarchy
58 · lockout: the lockout control persistent object
60 · If the argument argument can be loaded as a number it will be treat
62 as a handle, e.g. 0x81010013 and used directly.OBJECT.
63
65 Authorization for use of an object in TPM2.0 can come in 3 different
66 forms: 1. Password 2. HMAC 3. Sessions
67 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
69 fied".
70 Passwords
72 Passwords are interpreted in the following forms below using prefix
73 identifiers.
74 Note: By default passwords are assumed to be in the string form when
76 they do not have a prefix.
77 String
79 A string password, specified by prefix "str:" or it's absence (raw
80 string without prefix) is not interpreted, and is directly used for au‐
81 thorization.
82 Examples
84 foobar
85 str:foobar
86 Hex-string
88 A hex-string password, specified by prefix "hex:" is converted from a
89 hexidecimal form into a byte array form, thus allowing passwords with
90 non-printable and/or terminal un-friendly characters.
91 Example
93 hex:0x1122334455667788
94 File
96 A file based password, specified be prefix "file:" should be the path
97 of a file containing the password to be read by the tool or a "-" to
98 use stdin. Storing passwords in files prevents information leakage,
99 passwords passed as options can be read from the process list or common
100 shell history features.
101 Examples
103 # to use stdin and be prompted
104 file:-
105 # to use a file from a path
107 file:path/to/password/file
108 # to echo a password via stdin:
110 echo foobar | tpm2_tool -p file:-
111 # to use a bash here-string via stdin:
113 tpm2_tool -p file:- <<< foobar
115 Sessions
117 When using a policy session to authorize the use of an object, prefix
118 the option argument with the session keyword. Then indicate a path to
119 a session file that was created with tpm2_startauthsession(1). Option‐
120 ally, if the session requires an auth value to be sent with the session
121 handle (eg policy password), then append a + and a string as described
122 in the Passwords section.
123 Examples
125 To use a session context file called session.ctx.
126 session:session.ctx
128 To use a session context file called session.ctx AND send the authvalue
130 mypassword.
131 session:session.ctx+mypassword
133 To use a session context file called session.ctx AND send the HEX auth‐
135 value 0x11223344.
136 session:session.ctx+hex:11223344
138 PCR Authorizations
140 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
141 language. The PCR minilanguage is as follows:
142 <pcr-spec>=<raw-pcr-file>
143 The PCR spec is documented in in the section "PCR bank specifiers".
145 The raw-pcr-file is an optional the output of the raw PCR contents as
147 returned by tpm2_pcrread(1).
148 PCR bank specifiers (common/pcr.md)
150 Examples
152 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
153 er of:
154 pcr:sha256:0,1,2,3
156 specifying AUTH.
158
160 This collection of options are common to many programs and provide in‐
161 formation that many users may expect.
162 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
164 attempts to invoke the manpager for the tool, however, on failure
165 will output a short tool summary. This is the same behavior if the
166 "man" option argument is specified, however if explicit "man" is re‐
167 quested, the tool will provide errors from man on stderr. If the
168 "no-man" option if specified, or the manpager fails, the short op‐
169 tions will be output to stdout.
170 To successfully use the manpages feature requires the manpages to be
172 installed or on MANPATH, See man(1) for more details.
173 · -v, --version: Display version information for this tool, supported
175 tctis and exit.
176 · -V, --verbose: Increase the information that the tool prints to the
178 console during its execution. When using this option the file and
179 line number are printed.
180 · -Q, --quiet: Silence normal tool output to stdout.
182 · -Z, --enable-errata: Enable the application of errata fixups. Useful
184 if an errata fixup needs to be applied to commands sent to the TPM.
185 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
186 formation many users may expect.
187
189 The TCTI or "Transmission Interface" is the communication mechanism
190 with the TPM. TCTIs can be changed for communication with TPMs across
191 different mediums.
192 To control the TCTI, the tools respect:
194 1. The command line option -T or --tcti
196 2. The environment variable: TPM2TOOLS_TCTI.
198 Note: The command line option always overrides the environment vari‐
200 able.
201 The current known TCTIs are:
203 · tabrmd - The resource manager, called tabrmd
205 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
206 abrmd as a tcti name are synonymous.
207 · mssim - Typically used for communicating to the TPM software simula‐
209 tor.
210 · device - Used when talking directly to a TPM device file.
212 · none - Do not initalize a connection with the TPM. Some tools allow
214 for off-tpm options and thus support not using a TCTI. Tools that do
215 not support it will error when attempted to be used without a TCTI
216 connection. Does not support ANY options and MUST BE presented as
217 the exact text of "none".
218 The arguments to either the command line option or the environment
220 variable are in the form:
221 <tcti-name>:<tcti-option-config>
223 Specifying an empty string for either the <tcti-name> or <tcti-op‐
225 tion-config> results in the default being used for that portion respec‐
226 tively.
227 TCTI Defaults
229 When a TCTI is not specified, the default TCTI is searched for using
230 dlopen(3) semantics. The tools will search for tabrmd, device and
231 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
232 what TCTI will be chosen as the default by using the -v option to print
233 the version information. The "default-tcti" key-value pair will indi‐
234 cate which of the aforementioned TCTIs is the default.
235 Custom TCTIs
237 Any TCTI that implements the dynamic TCTI interface can be loaded. The
238 tools internally use dlopen(3), and the raw tcti-name value is used for
239 the lookup. Thus, this could be a path to the shared library, or a li‐
240 brary name as understood by dlopen(3) semantics.
241
243 This collection of options are used to configure the various known TCTI
244 modules available:
245 · device: For the device TCTI, the TPM character device file for use by
247 the device TCTI can be specified. The default is /dev/tpm0.
248 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
250 vice:/dev/tpm0"
251 · mssim: For the mssim TCTI, the domain name or IP address and port
253 number used by the simulator can be specified. The default are
254 127.0.0.1 and 2321.
255 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
257 TI="mssim:host=localhost,port=2321"
258 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
260 ries of simple key value pairs separated by a ',' character. Each
261 key and value string are separated by a '=' character.
262 · TCTI abrmd supports two keys:
264 1. 'bus_name' : The name of the tabrmd service on the bus (a
266 string).
267 2. 'bus_type' : The type of the dbus instance (a string) limited to
269 'session' and 'system'.
270 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
272 ample.FooBar:
273 \--tcti=tabrmd:bus_name=com.example.FooBar
275 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
277 sion:
278 \--tcti:bus_type=session
280 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
282 ules.
283
285 Write the file nv.data to index 0x01000001
286 tpm2_nvdefine -Q 1 -C o -s 32 -a "ownerread|policywrite|ownerwrite"
287 echo "please123abc" > nv.test_w
289 tpm2_nvwrite -Q 1 -C o -i nv.test_w
291
293 Tools can return any of the following codes:
294 · 0 - Success.
296 · 1 - General non-specific error.
298 · 2 - Options handling error.
300 · 3 - Authentication error.
302 · 4 - TCTI related error.
304 · 5 - Non supported scheme. Applicable to tpm2_testparams.
306
308 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
309
311 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
312tpm2-tools tpm2_nvwrite(1)