1tpm2_nvreadlock(1) General Commands Manual tpm2_nvreadlock(1)
2
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.
42 • ARGUMENT the command line argument specifies the NV index or offset
44 number.
45 References
48 The type of a context object, whether it is a handle or file name, is
49 determined according to the following logic in-order:
50 • If the argument is a file path, then the file is loaded as a restored
52 TPM transient object.
53 • If the argument is a prefix match on one of:
55 • owner: the owner hierarchy
57 • platform: the platform hierarchy
59 • endorsement: the endorsement hierarchy
61 • lockout: the lockout control persistent object
63 • If the argument argument can be loaded as a number it will be treat
65 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
66
68 Authorization for use of an object in TPM2.0 can come in 3 different
69 forms: 1. Password 2. HMAC 3. Sessions
70 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
72 fied”.
73 Passwords
75 Passwords are interpreted in the following forms below using prefix
76 identifiers.
77 Note: By default passwords are assumed to be in the string form when
79 they do not have a prefix.
80 String
82 A string password, specified by prefix “str:” or it’s absence (raw
83 string without prefix) is not interpreted, and is directly used for au‐
84 thorization.
85 Examples
87 foobar
88 str:foobar
89 Hex-string
91 A hex-string password, specified by prefix “hex:” is converted from a
92 hexidecimal form into a byte array form, thus allowing passwords with
93 non-printable and/or terminal un-friendly characters.
94 Example
96 hex:0x1122334455667788
97 File
99 A file based password, specified be prefix “file:” should be the path
100 of a file containing the password to be read by the tool or a “-” to
101 use stdin. Storing passwords in files prevents information leakage,
102 passwords passed as options can be read from the process list or common
103 shell history features.
104 Examples
106 # to use stdin and be prompted
107 file:-
108 # to use a file from a path
110 file:path/to/password/file
111 # to echo a password via stdin:
113 echo foobar | tpm2_tool -p file:-
114 # to use a bash here-string via stdin:
116 tpm2_tool -p file:- <<< foobar
118 Sessions
120 When using a policy session to authorize the use of an object, prefix
121 the option argument with the session keyword. Then indicate a path to
122 a session file that was created with tpm2_startauthsession(1). Option‐
123 ally, if the session requires an auth value to be sent with the session
124 handle (eg policy password), then append a + and a string as described
125 in the Passwords section.
126 Examples
128 To use a session context file called session.ctx.
129 session:session.ctx
131 To use a session context file called session.ctx AND send the authvalue
133 mypassword.
134 session:session.ctx+mypassword
136 To use a session context file called session.ctx AND send the HEX auth‐
138 value 0x11223344.
139 session:session.ctx+hex:11223344
141 PCR Authorizations
143 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
144 language. The PCR minilanguage is as follows:
145 <pcr-spec>=<raw-pcr-file>
146 The PCR spec is documented in in the section “PCR bank specifiers”.
148 The raw-pcr-file is an optional argument that contains the output of
150 the raw PCR contents as returned by tpm2_pcrread(1).
151 PCR bank specifiers (pcr.md)
153 Examples
155 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
156 er of:
157 pcr:sha256:0,1,2,3
159 specifying AUTH.
161
163 This collection of options are common to many programs and provide in‐
164 formation that many users may expect.
165 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
167 attempts to invoke the manpager for the tool, however, on failure
168 will output a short tool summary. This is the same behavior if the
169 “man” option argument is specified, however if explicit “man” is re‐
170 quested, the tool will provide errors from man on stderr. If the
171 “no-man” option if specified, or the manpager fails, the short op‐
172 tions will be output to stdout.
173 To successfully use the manpages feature requires the manpages to be
175 installed or on MANPATH, See man(1) for more details.
176 • -v, --version: Display version information for this tool, supported
178 tctis and exit.
179 • -V, --verbose: Increase the information that the tool prints to the
181 console during its execution. When using this option the file and
182 line number are printed.
183 • -Q, --quiet: Silence normal tool output to stdout.
185 • -Z, --enable-errata: Enable the application of errata fixups. Useful
187 if an errata fixup needs to be applied to commands sent to the TPM.
188 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
189 formation many users may expect.
190
192 The TCTI or “Transmission Interface” is the communication mechanism
193 with the TPM. TCTIs can be changed for communication with TPMs across
194 different mediums.
195 To control the TCTI, the tools respect:
197 1. The command line option -T or --tcti
199 2. The environment variable: TPM2TOOLS_TCTI.
201 Note: The command line option always overrides the environment vari‐
203 able.
204 The current known TCTIs are:
206 • tabrmd - The resource manager, called tabrmd
208 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
209 abrmd as a tcti name are synonymous.
210 • mssim - Typically used for communicating to the TPM software simula‐
212 tor.
213 • device - Used when talking directly to a TPM device file.
215 • none - Do not initalize a connection with the TPM. Some tools allow
217 for off-tpm options and thus support not using a TCTI. Tools that do
218 not support it will error when attempted to be used without a TCTI
219 connection. Does not support ANY options and MUST BE presented as
220 the exact text of “none”.
221 The arguments to either the command line option or the environment
223 variable are in the form:
224 <tcti-name>:<tcti-option-config>
226 Specifying an empty string for either the <tcti-name> or <tcti-op‐
228 tion-config> results in the default being used for that portion respec‐
229 tively.
230 TCTI Defaults
232 When a TCTI is not specified, the default TCTI is searched for using
233 dlopen(3) semantics. The tools will search for tabrmd, device and
234 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
235 what TCTI will be chosen as the default by using the -v option to print
236 the version information. The “default-tcti” key-value pair will indi‐
237 cate which of the aforementioned TCTIs is the default.
238 Custom TCTIs
240 Any TCTI that implements the dynamic TCTI interface can be loaded. The
241 tools internally use dlopen(3), and the raw tcti-name value is used for
242 the lookup. Thus, this could be a path to the shared library, or a li‐
243 brary name as understood by dlopen(3) semantics.
244
246 This collection of options are used to configure the various known TCTI
247 modules available:
248 • device: For the device TCTI, the TPM character device file for use by
250 the device TCTI can be specified. The default is /dev/tpm0.
251 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
253 vice:/dev/tpm0”
254 • mssim: For the mssim TCTI, the domain name or IP address and port
256 number used by the simulator can be specified. The default are
257 127.0.0.1 and 2321.
258 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
260 TI=“mssim:host=localhost,port=2321”
261 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
263 ries of simple key value pairs separated by a `,' character. Each
264 key and value string are separated by a `=' character.
265 • TCTI abrmd supports two keys:
267 1. `bus_name' : The name of the tabrmd service on the bus (a
269 string).
270 2. `bus_type' : The type of the dbus instance (a string) limited to
272 `session' and `system'.
273 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
275 ample.FooBar:
276 \--tcti=tabrmd:bus_name=com.example.FooBar
278 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
280 sion:
281 \--tcti:bus_type=session
283 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
285 ules.
286
288 Lock an index
289 tpm2_nvdefine -Q 1 -C o -s 32 \
290 -a "ownerread|policywrite|ownerwrite|read_stclear"
291 echo "foobar" > nv.readlock
293 tpm2_nvwrite -Q 0x01000001 -C o -i nv.readlock
295 tpm2_nvread -Q 1 -C o -s 6 -o 0
297 tpm2_nvreadlock -Q 1 -C o
299
301 Tools can return any of the following codes:
302 • 0 - Success.
304 • 1 - General non-specific error.
306 • 2 - Options handling error.
308 • 3 - Authentication error.
310 • 4 - TCTI related error.
312 • 5 - Non supported scheme. Applicable to tpm2_testparams.
314
316 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
317
319 See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)
320tpm2-tools tpm2_nvreadlock(1)