1tpm2_getcommandauditdigest(1)General Commands Manuatlpm2_getcommandauditdigest(1)
2
6 tpm2_getcommandauditdigest(1) - Retrieve the command audit attestation
7 data from the TPM.
8
10 tpm2_getcommandauditdigest [OPTIONS]
11
13 tpm2_getcommandauditdigest(1) - Retrieve the command audit attestation
14 data from the TPM. The attestation data includes the audit digest of
15 the commands in the setlist setup using the command tpm2_setcommandau‐
16 ditstatus. Also the attestation data includes the digest of the list
17 of commands setup for audit. The audit digest algorith is setup in the
18 tpm2_setcommandauditstatus.
19
21 • -P, --hierarchy-auth=AUTH:
22 Specifies the authorization value for the endorsement hierarchy.
24 • -c, --key-context=OBJECT:
26 Context object for the signing key that signs the attestation data.
28 • -p, --auth=AUTH:
30 Specifies the authorization value for key specified by option -c.
32 • -q, --qualification=HEX_STRING_OR_PATH:
34 Data given as a Hex string or binary file to qualify the quote, op‐
36 tional. This is typically used to add a nonce against replay at‐
37 tacks.
38 • -s, --signature=FILE:
40 Signature output file, records the signature in the format specified
42 via the -f option.
43 • -m, --message=FILE:
45 Message output file, records the quote message that makes up the data
47 that is signed by the TPM. This is the command audit digest attesta‐
48 tion data.
49 • -f, --format=FORMAT:
51 Format selection for the signature output file.
53 • -g, --hash-algorithm:
55 Hash algorithm for signature. Defaults to sha256.
57 • --scheme=ALGORITHM:
59 The signing scheme used to sign the message. Optional. Signing
61 schemes should follow the “formatting standards”, see section “Algo‐
62 rithm Specifiers”. Also, see section “Supported Signing Schemes” for
63 a list of supported signature schemes. If specified, the signature
64 scheme must match the key type. If left unspecified, a default sig‐
65 nature scheme for the key type will be used.
66 References
69 The type of a context object, whether it is a handle or file name, is
70 determined according to the following logic in-order:
71 • If the argument is a file path, then the file is loaded as a restored
73 TPM transient object.
74 • If the argument is a prefix match on one of:
76 • owner: the owner hierarchy
78 • platform: the platform hierarchy
80 • endorsement: the endorsement hierarchy
82 • lockout: the lockout control persistent object
84 • If the argument argument can be loaded as a number it will be treat
86 as a handle, e.g. 0x81010013 and used directly._OBJECT_.
87
89 Authorization for use of an object in TPM2.0 can come in 3 different
90 forms: 1. Password 2. HMAC 3. Sessions
91 NOTE: “Authorizations default to the EMPTY PASSWORD when not speci‐
93 fied”.
94 Passwords
96 Passwords are interpreted in the following forms below using prefix
97 identifiers.
98 Note: By default passwords are assumed to be in the string form when
100 they do not have a prefix.
101 String
103 A string password, specified by prefix “str:” or it’s absence (raw
104 string without prefix) is not interpreted, and is directly used for au‐
105 thorization.
106 Examples
108 foobar
109 str:foobar
110 Hex-string
112 A hex-string password, specified by prefix “hex:” is converted from a
113 hexidecimal form into a byte array form, thus allowing passwords with
114 non-printable and/or terminal un-friendly characters.
115 Example
117 hex:1122334455667788
118 File
120 A file based password, specified be prefix “file:” should be the path
121 of a file containing the password to be read by the tool or a “-” to
122 use stdin. Storing passwords in files prevents information leakage,
123 passwords passed as options can be read from the process list or common
124 shell history features.
125 Examples
127 # to use stdin and be prompted
128 file:-
129 # to use a file from a path
131 file:path/to/password/file
132 # to echo a password via stdin:
134 echo foobar | tpm2_tool -p file:-
135 # to use a bash here-string via stdin:
137 tpm2_tool -p file:- <<< foobar
139 Sessions
141 When using a policy session to authorize the use of an object, prefix
142 the option argument with the session keyword. Then indicate a path to
143 a session file that was created with tpm2_startauthsession(1). Option‐
144 ally, if the session requires an auth value to be sent with the session
145 handle (eg policy password), then append a + and a string as described
146 in the Passwords section.
147 Examples
149 To use a session context file called session.ctx.
150 session:session.ctx
152 To use a session context file called session.ctx AND send the authvalue
154 mypassword.
155 session:session.ctx+mypassword
157 To use a session context file called session.ctx AND send the HEX auth‐
159 value 0x11223344.
160 session:session.ctx+hex:11223344
162 PCR Authorizations
164 You can satisfy a PCR policy using the “pcr:” prefix and the PCR mini‐
165 language. The PCR minilanguage is as follows:
166 <pcr-spec>=<raw-pcr-file>
167 The PCR spec is documented in in the section “PCR bank specifiers”.
169 The raw-pcr-file is an optional argument that contains the output of
171 the raw PCR contents as returned by tpm2_pcrread(1).
172 PCR bank specifiers (pcr.md)
174 Examples
176 To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifi‐
177 er of:
178 pcr:sha256:0,1,2,3
180 specifying AUTH.
182
184 Format selection for the signature output file. tss (the default) will
185 output a binary blob according to the TPM 2.0 specification and any po‐
186 tential compiler padding. The option plain will output the plain sig‐
187 nature data as defined by the used cryptographic algorithm. signature
188 FORMAT.
189
191 This collection of options are common to many programs and provide in‐
192 formation that many users may expect.
193 • -h, --help=[man|no-man]: Display the tools manpage. By default, it
195 attempts to invoke the manpager for the tool, however, on failure
196 will output a short tool summary. This is the same behavior if the
197 “man” option argument is specified, however if explicit “man” is re‐
198 quested, the tool will provide errors from man on stderr. If the
199 “no-man” option if specified, or the manpager fails, the short op‐
200 tions will be output to stdout.
201 To successfully use the manpages feature requires the manpages to be
203 installed or on MANPATH, See man(1) for more details.
204 • -v, --version: Display version information for this tool, supported
206 tctis and exit.
207 • -V, --verbose: Increase the information that the tool prints to the
209 console during its execution. When using this option the file and
210 line number are printed.
211 • -Q, --quiet: Silence normal tool output to stdout.
213 • -Z, --enable-errata: Enable the application of errata fixups. Useful
215 if an errata fixup needs to be applied to commands sent to the TPM.
216 Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent. in‐
217 formation many users may expect.
218
220 The TCTI or “Transmission Interface” is the communication mechanism
221 with the TPM. TCTIs can be changed for communication with TPMs across
222 different mediums.
223 To control the TCTI, the tools respect:
225 1. The command line option -T or --tcti
227 2. The environment variable: TPM2TOOLS_TCTI.
229 Note: The command line option always overrides the environment vari‐
231 able.
232 The current known TCTIs are:
234 • tabrmd - The resource manager, called tabrmd
236 (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and
237 abrmd as a tcti name are synonymous.
238 • mssim - Typically used for communicating to the TPM software simula‐
240 tor.
241 • device - Used when talking directly to a TPM device file.
243 • none - Do not initalize a connection with the TPM. Some tools allow
245 for off-tpm options and thus support not using a TCTI. Tools that do
246 not support it will error when attempted to be used without a TCTI
247 connection. Does not support ANY options and MUST BE presented as
248 the exact text of “none”.
249 The arguments to either the command line option or the environment
251 variable are in the form:
252 <tcti-name>:<tcti-option-config>
254 Specifying an empty string for either the <tcti-name> or <tcti-op‐
256 tion-config> results in the default being used for that portion respec‐
257 tively.
258 TCTI Defaults
260 When a TCTI is not specified, the default TCTI is searched for using
261 dlopen(3) semantics. The tools will search for tabrmd, device and
262 mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query
263 what TCTI will be chosen as the default by using the -v option to print
264 the version information. The “default-tcti” key-value pair will indi‐
265 cate which of the aforementioned TCTIs is the default.
266 Custom TCTIs
268 Any TCTI that implements the dynamic TCTI interface can be loaded. The
269 tools internally use dlopen(3), and the raw tcti-name value is used for
270 the lookup. Thus, this could be a path to the shared library, or a li‐
271 brary name as understood by dlopen(3) semantics.
272
274 This collection of options are used to configure the various known TCTI
275 modules available:
276 • device: For the device TCTI, the TPM character device file for use by
278 the device TCTI can be specified. The default is /dev/tpm0.
279 Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“de‐
281 vice:/dev/tpm0”
282 • mssim: For the mssim TCTI, the domain name or IP address and port
284 number used by the simulator can be specified. The default are
285 127.0.0.1 and 2321.
286 Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TC‐
288 TI=“mssim:host=localhost,port=2321”
289 • abrmd: For the abrmd TCTI, the configuration string format is a se‐
291 ries of simple key value pairs separated by a `,' character. Each
292 key and value string are separated by a `=' character.
293 • TCTI abrmd supports two keys:
295 1. `bus_name' : The name of the tabrmd service on the bus (a
297 string).
298 2. `bus_type' : The type of the dbus instance (a string) limited to
300 `session' and `system'.
301 Specify the tabrmd tcti name and a config string of bus_name=com.ex‐
303 ample.FooBar:
304 \--tcti=tabrmd:bus_name=com.example.FooBar
306 Specify the default (abrmd) tcti and a config string of bus_type=ses‐
308 sion:
309 \--tcti:bus_type=session
311 NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod‐
313 ules.
314
316 tpm2_getcommandauditdigest -P ekpass -c key.ctx -p keypass -m att.data -s att.sig
317
319 Tools can return any of the following codes:
320 • 0 - Success.
322 • 1 - General non-specific error.
324 • 2 - Options handling error.
326 • 3 - Authentication error.
328 • 4 - TCTI related error.
330 • 5 - Non supported scheme. Applicable to tpm2_testparams.
332
334 Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
335
337 See the Mailing List (https://lists.linuxfoundation.org/mailman/listin‐
338 fo/tpm2)
339tpm2-tools tpm2_getcommandauditdigest(1)