1tpm2_nvreadlock(1) General Commands Manual tpm2_nvreadlock(1)
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6 tpm2_nvreadlock(1) - Lock the Non-Volatile (NV) index for further
7 reads.
8
10 tpm2_nvreadlock [OPTIONS] [ARGUMENT]
11
13 tpm2_nvreadlock(1) - Lock the Non-Volatile (NV) index for further
14 reads. The lock on the NN index is unlocked when the TPM is restarted
15 and the NV index becomes readable again. The index can be specified as
16 raw handle or an offset value to the nv handle range “TPM2_HR_NV_IN‐
17 DEX”.
18
20 • -C, --hierarchy=OBJECT:
21 Specifies the hierarchy used to authorize. Supported options are:
22 • o for TPM_RH_OWNER
24 • p for TPM_RH_PLATFORM
26 • <num> where a hierarchy handle or nv-index may be used.
28 When -C isn’t explicitly passed the index handle will be used to au‐
30 thorize against the index. The index auth value is set via the -p
31 option to tpm2_nvdefine(1).
32 • -P, --auth=AUTH:
34 Specifies the authorization value for the hierarchy.
36 • --cphash=FILE
38 File path to record the hash of the command parameters. This is com‐
40 monly termed as cpHash. NOTE: When this option is selected, The tool
41 will not actually execute the command, it simply returns a cpHash un‐
42 less rphash is also required.
43 • --rphash=FILE
45 File path to record the hash of the response parameters. This is
47 commonly termed as rpHash.
48 • -S, --session=FILE:
50 The session created using tpm2_startauthsession. This can be used to
52 specify an auxiliary session for auditing and or encryption/decryp‐
53 tion of the parameters.
54 • -n, --name=FILE:
56 The name of the NV index that must be provided when only calculating
58 the cpHash without actually dispatching the command to the TPM.
59 • ARGUMENT the command line argument specifies the NV index or offset
61 number.
62 References
65 The type of a context object, whether it is a handle or file name, is
66 determined according to the following logic in-order:
67 • If the argument is a file path, then the file is loaded as a restored
69 TPM transient object.
70 • If the argument is a prefix match on one of:
72 • owner: the owner hierarchy
74 • platform: the platform hierarchy
76 • endorsement: the endorsement hierarchy
78 • lockout: the lockout control persistent object
80 • If the argument argument can be loaded as a number it will be treat
82 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
83
85 Authorization for use of an object in TPM2.0 can come in 3 different
86 forms: 1. Password 2. HMAC 3. Sessions
87 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
89 fied”.
90 Passwords
92 Passwords are interpreted in the following forms below using prefix
93 identifiers.
94 Note: By default passwords are assumed to be in the string form when
96 they do not have a prefix.
97 String
99 A string password, specified by prefix “str:” or it’s absence (raw
100 string without prefix) is not interpreted, and is directly used for au‐
101 thorization.
102 Examples
104 foobar
105 str:foobar
106 Hex-string
108 A hex-string password, specified by prefix “hex:” is converted from a
109 hexidecimal form into a byte array form, thus allowing passwords with
110 non-printable and/or terminal un-friendly characters.
111 Example
113 hex:1122334455667788
114 File
116 A file based password, specified be prefix “file:” should be the path
117 of a file containing the password to be read by the tool or a “-” to
118 use stdin. Storing passwords in files prevents information leakage,
119 passwords passed as options can be read from the process list or common
120 shell history features.
121 Examples
123 # to use stdin and be prompted
124 file:-
125 # to use a file from a path
127 file:path/to/password/file
128 # to echo a password via stdin:
130 echo foobar | tpm2_tool -p file:-
131 # to use a bash here-string via stdin:
133 tpm2_tool -p file:- <<< foobar
135 Sessions
137 When using a policy session to authorize the use of an object, prefix
138 the option argument with the session keyword. Then indicate a path to
139 a session file that was created with tpm2_startauthsession(1). Option‐
140 ally, if the session requires an auth value to be sent with the session
141 handle (eg policy password), then append a + and a string as described
142 in the Passwords section.
143 Examples
145 To use a session context file called session.ctx.
146 session:session.ctx
148 To use a session context file called session.ctx AND send the authvalue
150 mypassword.
151 session:session.ctx+mypassword
153 To use a session context file called session.ctx AND send the HEX auth‐
155 value 0x11223344.
156 session:session.ctx+hex:11223344
158 PCR Authorizations
160 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
161 language. The PCR minilanguage is as follows:
162 <pcr-spec>=<raw-pcr-file>
163 The PCR spec is documented in in the section “PCR bank specifiers”.
165 The raw-pcr-file is an optional argument that contains the output of
167 the raw PCR contents as returned by tpm2_pcrread(1).
168 PCR bank specifiers (pcr.md)
170 Examples
172 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
173 er of:
174 pcr:sha256:0,1,2,3
176 specifying AUTH.
178
180 This collection of options are common to many programs and provide in‐
181 formation that many users may expect.
182 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
184 attempts to invoke the manpager for the tool, however, on failure
185 will output a short tool summary. This is the same behavior if the
186 “man” option argument is specified, however if explicit “man” is re‐
187 quested, the tool will provide errors from man on stderr. If the
188 “no-man” option if specified, or the manpager fails, the short op‐
189 tions will be output to stdout.
190 To successfully use the manpages feature requires the manpages to be
192 installed or on MANPATH, See man(1) for more details.
193 • -v, --version: Display version information for this tool, supported
195 tctis and exit.
196 • -V, --verbose: Increase the information that the tool prints to the
198 console during its execution. When using this option the file and
199 line number are printed.
200 • -Q, --quiet: Silence normal tool output to stdout.
202 • -Z, --enable-errata: Enable the application of errata fixups. Useful
204 if an errata fixup needs to be applied to commands sent to the TPM.
205 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
206 formation many users may expect.
207
209 The TCTI or “Transmission Interface” is the communication mechanism
210 with the TPM. TCTIs can be changed for communication with TPMs across
211 different mediums.
212 To control the TCTI, the tools respect:
214 1. The command line option -T or --tcti
216 2. The environment variable: TPM2TOOLS_TCTI.
218 Note: The command line option always overrides the environment vari‐
220 able.
221 The current known TCTIs are:
223 • tabrmd - The resource manager, called tabrmd
225 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
226 abrmd as a tcti name are synonymous.
227 • mssim - Typically used for communicating to the TPM software simula‐
229 tor.
230 • device - Used when talking directly to a TPM device file.
232 • none - Do not initalize a connection with the TPM. Some tools allow
234 for off-tpm options and thus support not using a TCTI. Tools that do
235 not support it will error when attempted to be used without a TCTI
236 connection. Does not support ANY options and MUST BE presented as
237 the exact text of “none”.
238 The arguments to either the command line option or the environment
240 variable are in the form:
241 <tcti-name>:<tcti-option-config>
243 Specifying an empty string for either the <tcti-name> or <tcti-op‐
245 tion-config> results in the default being used for that portion respec‐
246 tively.
247 TCTI Defaults
249 When a TCTI is not specified, the default TCTI is searched for using
250 dlopen(3) semantics. The tools will search for tabrmd, device and
251 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
252 what TCTI will be chosen as the default by using the -v option to print
253 the version information. The “default-tcti” key-value pair will indi‐
254 cate which of the aforementioned TCTIs is the default.
255 Custom TCTIs
257 Any TCTI that implements the dynamic TCTI interface can be loaded. The
258 tools internally use dlopen(3), and the raw tcti-name value is used for
259 the lookup. Thus, this could be a path to the shared library, or a li‐
260 brary name as understood by dlopen(3) semantics.
261
263 This collection of options are used to configure the various known TCTI
264 modules available:
265 • device: For the device TCTI, the TPM character device file for use by
267 the device TCTI can be specified. The default is /dev/tpm0.
268 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
270 vice:/dev/tpm0”
271 • mssim: For the mssim TCTI, the domain name or IP address and port
273 number used by the simulator can be specified. The default are
274 127.0.0.1 and 2321.
275 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
277 TI=“mssim:host=localhost,port=2321”
278 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
280 ries of simple key value pairs separated by a `,' character. Each
281 key and value string are separated by a `=' character.
282 • TCTI abrmd supports two keys:
284 1. `bus_name' : The name of the tabrmd service on the bus (a
286 string).
287 2. `bus_type' : The type of the dbus instance (a string) limited to
289 `session' and `system'.
290 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
292 ample.FooBar:
293 \--tcti=tabrmd:bus_name=com.example.FooBar
295 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
297 sion:
298 \--tcti:bus_type=session
300 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
302 ules.
303
305 Lock an index
306 tpm2_nvdefine -Q 1 -C o -s 32 \
307 -a "ownerread|policywrite|ownerwrite|read_stclear"
308 echo "foobar" > nv.readlock
310 tpm2_nvwrite -Q 0x01000001 -C o -i nv.readlock
312 tpm2_nvread -Q 1 -C o -s 6 -o 0
314 tpm2_nvreadlock -Q 1 -C o
316
318 Tools can return any of the following codes:
319 • 0 - Success.
321 • 1 - General non-specific error.
323 • 2 - Options handling error.
325 • 3 - Authentication error.
327 • 4 - TCTI related error.
329 • 5 - Non supported scheme. Applicable to tpm2_testparams.
331
333 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
334
336 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
337 fo/tpm2)
338tpm2-tools tpm2_nvreadlock(1)