| tpm2_createprimary(1) | General Commands Manual | tpm2_createprimary(1) |
tpm2_createprimary(1) - Create a primary key.
tpm2_createprimary [OPTIONS]
tpm2_createprimary(1) - This command is used to create a primary object under one of the hierarchies: Owner, Platform, Endorsement, NULL. The command will create and load a Primary Object. The sensitive and public portions are not returned. A context file for the created object’s handle is saved as a file for future interactions with the created primary.
The hierarchy under which the object is created. This will also dictate which authorization secret (if any) must be supplied. Defaults to TPM_RH_OWNER, when no value specified. Supported options are:
The authorization value for the hierarchy specified with -C.
The authorization value for the primary object created.
The hash algorithm to use for generating the objects name. Defaults to sha256 if not specified.
The algorithm type for the generated primary key. Defaults to rsa2048:null:aes128cfb.
The file path to save the object context of the generated primary object.
An optional file input or hex string that contains the policy digest for policy based authorization of the object.
The object attributes, optional. Defaults to: TPMA_OBJECT_RESTRICTED|TPMA_OBJECT_DECRYPT|TPMA_OBJECT_FIXEDTPM| TPMA_OBJECT_FIXEDPARENT|TPMA_OBJECT_SENSITIVEDATAORIGIN| TPMA_OBJECT_USERWITHAUTH
An optional file input that contains the unique field of TPMT_PUBLIC in little-endian format. Primary key creator may place information that causes the primary key generation scheme internal to the TPM to generate statistically unique values. The TPM v2.0 specification calls this field unique and overloads it so that it contains one value when the application provides this structure as input and another value when the applications receives this structure as output (like public portion of the rsa key).
If the data is specified as a file, the user is responsible for ensuring that this buffer is formatted per TPMU_PUBLIC_ID union.
The unique data can also be retrieved from stdin buffer by specifying “-” as the –unique-data option value and the tool will parse the key type and associate the input data with the unique data buffer associated with the key type.
NOTE:
An optional file output that saves the creation data for certification.
An optional file output that saves the key template data (TPM2B_PUBLIC) to be used in tpm2_policytemplate.
An optional file output that saves the creation ticket for certification.
An optional file output that saves the creation hash for certification.
An optional file or hex string to add unique data to the creation data. Note that it does not contribute in creating statistically unique object.
The list of PCR banks and selected PCRs’ ids for each bank to be included in the creation data for certification.
File path to record the hash of the command parameters. This is commonly termed as cpHash. NOTE: When this option is selected, The tool will not actually execute the command, it simply returns a cpHash.
Format selection for the public key output file. `tss' (the default) will output a binary blob according to the TPM 2.0 Specification. `pem' will output an OpenSSL compatible PEM encoded public key. `der' will output an OpenSSL compatible DER encoded public key. `tpmt' will output a binary blob of the TPMT_PUBLIC struct referenced by TPM 2.0 specs.
Public key format.
The output file path, recording the public portion of the object.
The type of a context object, whether it is a handle or file name, is determined according to the following logic in-order:
Authorization for use of an object in TPM2.0 can come in 3 different forms: 1. Password 2. HMAC 3. Sessions
NOTE: “Authorizations default to the EMPTY PASSWORD when not specified”.
Passwords are interpreted in the following forms below using prefix identifiers.
Note: By default passwords are assumed to be in the string form when they do not have a prefix.
A string password, specified by prefix “str:” or it’s absence (raw string without prefix) is not interpreted, and is directly used for authorization.
foobar
str:foobar
A hex-string password, specified by prefix “hex:” is converted from a hexidecimal form into a byte array form, thus allowing passwords with non-printable and/or terminal un-friendly characters.
hex:1122334455667788
A file based password, specified be prefix “file:” should be the path of a file containing the password to be read by the tool or a “-” to use stdin. Storing passwords in files prevents information leakage, passwords passed as options can be read from the process list or common shell history features.
# to use stdin and be prompted
file:-
# to use a file from a path
file:path/to/password/file
# to echo a password via stdin:
echo foobar | tpm2_tool -p file:-
# to use a bash here-string via stdin:
tpm2_tool -p file:- <<< foobar
When using a policy session to authorize the use of an object, prefix the option argument with the session keyword. Then indicate a path to a session file that was created with tpm2_startauthsession(1). Optionally, if the session requires an auth value to be sent with the session handle (eg policy password), then append a + and a string as described in the Passwords section.
To use a session context file called session.ctx.
session:session.ctx
To use a session context file called session.ctx AND send the authvalue mypassword.
session:session.ctx+mypassword
To use a session context file called session.ctx AND send the HEX authvalue 0x11223344.
session:session.ctx+hex:11223344
You can satisfy a PCR policy using the “pcr:” prefix and the PCR minilanguage. The PCR minilanguage is as follows: <pcr-spec>=<raw-pcr-file>
The PCR spec is documented in in the section “PCR bank specifiers”.
The raw-pcr-file is an optional argument that contains the output of the raw PCR contents as returned by tpm2_pcrread(1).
PCR bank specifiers
To satisfy a PCR policy of sha256 on banks 0, 1, 2 and 3 use a specifier of:
pcr:sha256:0,1,2,3
specifying AUTH.
Options that take algorithms support “nice-names”.
There are two major algorithm specification string classes, simple and complex. Only certain algorithms will be accepted by the TPM, based on usage and conditions.
These are strings with no additional specification data. When creating objects, non-specified portions of an object are assumed to defaults. You can find the list of known “Simple Specifiers” below.
Objects, when specified for creation by the TPM, have numerous algorithms to populate in the public data. Things like type, scheme and asymmetric details, key size, etc. Below is the general format for specifying this data: <type>:<scheme>:<symmetric-details>
This portion of the complex algorithm specifier is required. The remaining scheme and symmetric details will default based on the type specified and the type of the object being created.
Next, is an optional field, it can be skipped.
Schemes are usually Signing Schemes or Asymmetric Encryption Schemes. Most signing schemes take a hash algorithm directly following the signing scheme. If the hash algorithm is missing, it defaults to sha256. Some take no arguments, and some take multiple arguments.
These scheme specifiers are followed by a dash and a valid hash algorithm, For example: oaep-sha256.
This scheme specifier is followed by a count (max size UINT16) then followed by a dash(-) and a valid hash algorithm. * ecdaa For example, ecdaa4-sha256. If no count is specified, it defaults to 4.
This scheme specifier takes NO arguments. * rsaes
This field is optional, and defaults based on the type of object being created and it’s attributes. Generally, any valid Symmetric specifier from the Type Specifiers list should work. If not specified, an asymmetric objects symmetric details defaults to aes128cfb.
tpm2_create -C parent.ctx -G rsa2048:rsaes -u key.pub -r key.priv
/tpm2_create -C parent.ctx -G ecc256:ecdaa4-sha384 -u key.pub -r key.priv cryptographic algorithms ALGORITHM.
Object Attributes are used to control various properties of created objects. When specified as an option, either the raw bitfield mask or “nice-names” may be used. The values can be found in Table 31 Part 2 of the TPM2.0 specification, which can be found here:
<https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-2-Structures-01.38.pdf>
Nice names are calculated by taking the name field of table 31 and removing the prefix TPMA_OBJECT_ and lowercasing the result. Thus, TPMA_OBJECT_FIXEDTPM becomes fixedtpm. Nice names can be joined using the bitwise or “|” symbol.
For instance, to set The fields TPMA_OBJECT_FIXEDTPM, TPMA_OBJECT_NODA, and TPMA_OBJECT_SIGN_ENCRYPT, the argument would be:
fixedtpm|noda|sign specifying the object attributes ATTRIBUTES.
This collection of options are common to many programs and provide information that many users may expect.
To successfully use the manpages feature requires the manpages to be installed or on MANPATH, See man(1) for more details.
The TCTI or “Transmission Interface” is the communication mechanism with the TPM. TCTIs can be changed for communication with TPMs across different mediums.
To control the TCTI, the tools respect:
Note: The command line option always overrides the environment variable.
The current known TCTIs are:
The arguments to either the command line option or the environment variable are in the form:
<tcti-name>:<tcti-option-config>
Specifying an empty string for either the <tcti-name> or <tcti-option-config> results in the default being used for that portion respectively.
When a TCTI is not specified, the default TCTI is searched for using dlopen(3) semantics. The tools will search for tabrmd, device and mssim TCTIs IN THAT ORDER and USE THE FIRST ONE FOUND. You can query what TCTI will be chosen as the default by using the -v option to print the version information. The “default-tcti” key-value pair will indicate which of the aforementioned TCTIs is the default.
Any TCTI that implements the dynamic TCTI interface can be loaded. The tools internally use dlopen(3), and the raw tcti-name value is used for the lookup. Thus, this could be a path to the shared library, or a library name as understood by dlopen(3) semantics.
This collection of options are used to configure the various known TCTI modules available:
Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“device:/dev/tpm0”
Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TCTI=“mssim:host=localhost,port=2321”
Specify the tabrmd tcti name and a config string of bus_name=com.example.FooBar:
\--tcti=tabrmd:bus_name=com.example.FooBar
Specify the default (abrmd) tcti and a config string of bus_type=session:
\--tcti:bus_type=session
NOTE: abrmd and tabrmd are synonymous. the various known TCTI modules.
tpm2_createprimary -C o -g sha256 -G ecc -c context.out
See : https://trustedcomputinggroup.org/wp-content/uploads/TCG-TPM-v2.0-Provisioning-Guidance-Published-v1r1.pdf
Where unique.dat contains the binary-formatted data: 0x00 0x01 (0x00 * 256)
tpm2_createprimary -C o -G rsa2048:aes128cfb -g sha256 -c prim.ctx \
-a 'restricted|decrypt|fixedtpm|fixedparent|sensitivedataorigin|userwithauth|\
noda' -u unique.dat
## Create a primary object and output the public key in pem format
tpm2_createprimary -c primary.ctx --format=pem --output=public.pem
Tools can return any of the following codes:
Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
See the Mailing List (https://lists.linuxfoundation.org/mailman/listinfo/tpm2)
| tpm2-tools |