1tpm2_activatecredential(1) General Commands Manual tpm2_activatecredential(1)
2
6 tpm2_activatecredential(1) - Enables access to the credential qualifier
7 to recover the credential secret.
8
10 tpm2_activatecredential [OPTIONS]
11
13 tpm2_activatecredential(1) - Enables the association of a credential
14 with an object in a way that ensures that the TPM has validated the pa‐
15 rameters of the credentialed object. In an attestation scheme , this
16 guarantees the registrar that the attestation key belongs to the TPM
17 with a qualified parent key in the TPM.
18
20 · -c, --credentialedkey-context=OBJECT:
21 Object associated with the created certificate by CA.
23 · -C, --credentialkey-context=OBJECT:
25 The loaded object used to decrypt the random seed.
27 · -p, --credentialedkey-auth=AUTH:
29 The auth value of the credentialed object specified with -c.
31 · -P, --credentialkey-auth=AUTH:
33 The auth value of the credential object specified with -C.
35 · -i, --credential-blob=FILE:
37 The input file path containing the credential blob and secret created
39 with the tpm2_makecredential(1) tool.
40 · -o, --certinfo-data=FILE:
42 The output file path to save the decrypted credential secret informa‐
44 tion.
45 · --cphash=FILE
47 File path to record the hash of the command parameters. This is com‐
49 monly termed as cpHash. NOTE: When this option is selected, The tool
50 will not actually execute the command, it simply returns a cpHash.
51 References
54 The type of a context object, whether it is a handle or file name, is
55 determined according to the following logic in-order:
56 · If the argument is a file path, then the file is loaded as a restored
58 TPM transient object.
59 · If the argument is a prefix match on one of:
61 · owner: the owner hierarchy
63 · platform: the platform hierarchy
65 · endorsement: the endorsement hierarchy
67 · lockout: the lockout control persistent object
69 · If the argument argument can be loaded as a number it will be treat
71 as a handle, e.g. 0x81010013 and used directly.OBJECT.
72
74 Authorization for use of an object in TPM2.0 can come in 3 different
75 forms: 1. Password 2. HMAC 3. Sessions
76 NOTE: "Authorizations default to the EMPTY PASSWORD when not speci‐
78 fied".
79 Passwords
81 Passwords are interpreted in the following forms below using prefix
82 identifiers.
83 Note: By default passwords are assumed to be in the string form when
85 they do not have a prefix.
86 String
88 A string password, specified by prefix "str:" or it's absence (raw
89 string without prefix) is not interpreted, and is directly used for au‐
90 thorization.
91 Examples
93 foobar
94 str:foobar
95 Hex-string
97 A hex-string password, specified by prefix "hex:" is converted from a
98 hexidecimal form into a byte array form, thus allowing passwords with
99 non-printable and/or terminal un-friendly characters.
100 Example
102 hex:0x1122334455667788
103 File
105 A file based password, specified be prefix "file:" should be the path
106 of a file containing the password to be read by the tool or a "-" to
107 use stdin. Storing passwords in files prevents information leakage,
108 passwords passed as options can be read from the process list or common
109 shell history features.
110 Examples
112 # to use stdin and be prompted
113 file:-
114 # to use a file from a path
116 file:path/to/password/file
117 # to echo a password via stdin:
119 echo foobar | tpm2_tool -p file:-
120 # to use a bash here-string via stdin:
122 tpm2_tool -p file:- <<< foobar
124 Sessions
126 When using a policy session to authorize the use of an object, prefix
127 the option argument with the session keyword. Then indicate a path to
128 a session file that was created with tpm2_startauthsession(1). Option‐
129 ally, if the session requires an auth value to be sent with the session
130 handle (eg policy password), then append a + and a string as described
131 in the Passwords section.
132 Examples
134 To use a session context file called session.ctx.
135 session:session.ctx
137 To use a session context file called session.ctx AND send the authvalue
139 mypassword.
140 session:session.ctx+mypassword
142 To use a session context file called session.ctx AND send the HEX auth‐
144 value 0x11223344.
145 session:session.ctx+hex:11223344
147 PCR Authorizations
149 You can satisfy a PCR policy using the "pcr:" prefix and the PCR mini‐
150 language. The PCR minilanguage is as follows:
151 <pcr-spec>=<raw-pcr-file>
152 The PCR spec is documented in in the section "PCR bank specifiers".
154 The raw-pcr-file is an optional the output of the raw PCR contents as
156 returned by tpm2_pcrread(1).
157 PCR bank specifiers (common/pcr.md)
159 Examples
161 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
162 er of:
163 pcr:sha256:0,1,2,3
165 specifying AUTH.
167
169 This collection of options are common to many programs and provide in‐
170 formation that many users may expect.
171 · -h, --help=[man|no-man]: Display the tools manpage. By default, it
173 attempts to invoke the manpager for the tool, however, on failure
174 will output a short tool summary. This is the same behavior if the
175 "man" option argument is specified, however if explicit "man" is re‐
176 quested, the tool will provide errors from man on stderr. If the
177 "no-man" option if specified, or the manpager fails, the short op‐
178 tions will be output to stdout.
179 To successfully use the manpages feature requires the manpages to be
181 installed or on MANPATH, See man(1) for more details.
182 · -v, --version: Display version information for this tool, supported
184 tctis and exit.
185 · -V, --verbose: Increase the information that the tool prints to the
187 console during its execution. When using this option the file and
188 line number are printed.
189 · -Q, --quiet: Silence normal tool output to stdout.
191 · -Z, --enable-errata: Enable the application of errata fixups. Useful
193 if an errata fixup needs to be applied to commands sent to the TPM.
194 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
195 formation many users may expect.
196
198 The TCTI or "Transmission Interface" is the communication mechanism
199 with the TPM. TCTIs can be changed for communication with TPMs across
200 different mediums.
201 To control the TCTI, the tools respect:
203 1. The command line option -T or --tcti
205 2. The environment variable: TPM2TOOLS_TCTI.
207 Note: The command line option always overrides the environment vari‐
209 able.
210 The current known TCTIs are:
212 · tabrmd - The resource manager, called tabrmd
214 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
215 abrmd as a tcti name are synonymous.
216 · mssim - Typically used for communicating to the TPM software simula‐
218 tor.
219 · device - Used when talking directly to a TPM device file.
221 · none - Do not initalize a connection with the TPM. Some tools allow
223 for off-tpm options and thus support not using a TCTI. Tools that do
224 not support it will error when attempted to be used without a TCTI
225 connection. Does not support ANY options and MUST BE presented as
226 the exact text of "none".
227 The arguments to either the command line option or the environment
229 variable are in the form:
230 <tcti-name>:<tcti-option-config>
232 Specifying an empty string for either the <tcti-name> or <tcti-op‐
234 tion-config> results in the default being used for that portion respec‐
235 tively.
236 TCTI Defaults
238 When a TCTI is not specified, the default TCTI is searched for using
239 dlopen(3) semantics. The tools will search for tabrmd, device and
240 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
241 what TCTI will be chosen as the default by using the -v option to print
242 the version information. The "default-tcti" key-value pair will indi‐
243 cate which of the aforementioned TCTIs is the default.
244 Custom TCTIs
246 Any TCTI that implements the dynamic TCTI interface can be loaded. The
247 tools internally use dlopen(3), and the raw tcti-name value is used for
248 the lookup. Thus, this could be a path to the shared library, or a li‐
249 brary name as understood by dlopen(3) semantics.
250
252 This collection of options are used to configure the various known TCTI
253 modules available:
254 · device: For the device TCTI, the TPM character device file for use by
256 the device TCTI can be specified. The default is /dev/tpm0.
257 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI="de‐
259 vice:/dev/tpm0"
260 · mssim: For the mssim TCTI, the domain name or IP address and port
262 number used by the simulator can be specified. The default are
263 127.0.0.1 and 2321.
264 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
266 TI="mssim:host=localhost,port=2321"
267 · abrmd: For the abrmd TCTI, the configuration string format is a se‐
269 ries of simple key value pairs separated by a ',' character. Each
270 key and value string are separated by a '=' character.
271 · TCTI abrmd supports two keys:
273 1. 'bus_name' : The name of the tabrmd service on the bus (a
275 string).
276 2. 'bus_type' : The type of the dbus instance (a string) limited to
278 'session' and 'system'.
279 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
281 ample.FooBar:
282 \--tcti=tabrmd:bus_name=com.example.FooBar
284 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
286 sion:
287 \--tcti:bus_type=session
289 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
291 ules.
292
294 echo "12345678" > secret.data
295 tpm2_createek -Q -c 0x81010001 -G rsa -u ek.pub
297 tpm2_createak -C 0x81010001 -c ak.ctx -G rsa -g sha256 -s rsassa -u ak.pub \
299 -n ak.name -p akpass> ak.out
300 file_size=`stat --printf="%s" ak.name`
302 loaded_key_name=`cat ak.name | xxd -p -c $file_size`
303 tpm2_makecredential -Q -e ek.pub -s secret.data -n $loaded_key_name \
305 -o mkcred.out
306 tpm2_startauthsession --policy-session -S session.ctx
308 TPM2_RH_ENDORSEMENT=0x4000000B
310 tpm2_policysecret -S session.ctx -c $TPM2_RH_ENDORSEMENT
311 tpm2_activatecredential -Q -c ak.ctx -C 0x81010001 -i mkcred.out \
313 -o actcred.out -p akpass -P"session:session.ctx"
314 tpm2_flushcontext session.ctx
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.01.org/mailman/listinfo/tpm2)
337tpm2-tools tpm2_activatecredential(1)