tpm2_import - Man Page

tpm2_import [Options]

tpm2_import(1) - Imports an external generated key as TPM managed key object. It requires that the parent key object be a RSA key. Can also import a TPM managed key object created by the tpm2_duplicate tool.

These options control the key importation process:

• -G, --key-algorithm=ALGORITHM:

  The algorithm used by the key to be imported. Supports:

  • aes - AES 128, 192 or 256 key.
  • rsa - RSA 1024, 2048, 3072, or 4096 key.
  • ecc - ECC NIST P192, P224, P256, P384 or P521 public and private key.
  • hmac - HMAC key.

• -g, --hash-algorithm=ALGORITHM:

  The hash algorithm for generating the objects name. This is optional and defaults to sha256 when not specified. Algorithms should follow the “formatting standards”, see section “Algorithm Specifiers”. Also, see section “Supported Hash Algorithms” for a list of supported hash algorithms.

• -i, --input=File:

  Specifies the filename of the key to be imported. For AES keys, this file is the raw key bytes. For assymetric keys in PEM or DER format. A typical file is generated with openssl genrsa.

• -C, --parent-context=OBJECT:

  The parent key object.

• -U, --parent-public=File:

  Optional. Specifies the parent key public data file input. This can be read with tpm2_readpublic(1) tool. If not specified, the tool invokes a tpm2_readpublic on the parent object.

• -k, --encryption-key=File:

  Optional. Specifies the file containing the symmetric algorithm key that was used for the inner wrapper. If the file is specified the tool assumes the algorithm is AES 128 in CFB mode otherwise none.

• -r, --private=File:

  Specifies the file path required to save the encrypted private portion of the object imported as key.

  When importing a duplicated object this option specifies the file containing the private portion of the object to be imported. # Protection Details

Objects that can move outside of TPM need to be protected (confidentiality and integrity). For instance, transient objects require that TPM protected data (key or seal material) be stored outside of the TPM. This is seen in tools like tpm2_create(1), where the -r option outputs this protected data. This blob contains the sensitive portions of the object. The sensitive portions of the object are protected by the parent object, using the parent’s symmetric encryption details to encrypt the sensitive data and HMAC it.

In-depth details can be found in sections 23 of:

• https://trustedcomputinggroup.org/wp-content/uploads/TPM-Rev-2.0-Part-1-Architecture-01.38.pdf

Notably Figure 20, is relevant, even though it’s specifically referring to duplication blobs, the process is identical.

If the output is from tpm2_duplicate(1), the output will be slightly different, as described fully in section 23.

• -u, --public=File:

  Specifies the file path required to save the public portion of the object imported as key

  When importing a duplicated object this option specifies the file containing the public portion of the object to be imported.

• -a, --attributes=ATTRIBUTES:

  The object attributes, optional.

• -P, --parent-auth=AUTH:

  The authorization value for using the parent key specified with -C.

• -p, --key-auth=AUTH:

  The authorization value for the imported key, optional.

• -L, --policy=POLICY or HEX_STRING:

  The policy file or policy hex string used for authorization to the object.

• -s, --seed=File:

  Specifies the file containing the encrypted seed of the duplicated object.

  In order to perform an “unencrypted import” a seed file with the content 0x0000 needs to be provided (e.g. printf “0000” | xxd -r -p >seed.file).

• --passin=OSSL_PEM_FILE_PASSWORD

  An optional password for an Open SSL (OSSL) provided input file. It mirrors the -passin option of OSSL and is known to support the pass, file, env, fd and plain password formats of openssl. (see man(1) openssl) for more.

• --cphash=File

  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.

The type of a context object, whether it is a handle or file name, is determined according to the following logic in-order:

• If the argument is a file path, then the file is loaded as a restored TPM transient object.

• If the argument is a prefix match on one of:

  • owner: the owner hierarchy
  • platform: the platform hierarchy
  • endorsement: the endorsement hierarchy
  • lockout: the lockout control persistent object
• If the argument argument can be loaded as a number it will be treat as a handle, e.g. 0x81010013 and used directly._OBJECT_.

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”.

foobar
str:foobar

hex:1122334455667788

# 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

session:session.ctx

session:session.ctx+mypassword

session:session.ctx+hex:11223344

pcr:sha256:0,1,2,3

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.

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.

• -h, --help=[man|no-man]: Display the tools manpage. By default, it attempts to invoke the manpager for the tool, however, on failure will output a short tool summary. This is the same behavior if the “man” option argument is specified, however if explicit “man” is requested, the tool will provide errors from man on stderr. If the “no-man” option if specified, or the manpager fails, the short options will be output to stdout.

  To successfully use the manpages feature requires the manpages to be installed or on MANPATH, See man(1) for more details.

• -v, --version: Display version information for this tool, supported tctis and exit.
• -V, --verbose: Increase the information that the tool prints to the console during its execution. When using this option the file and line number are printed.
• -Q, --quiet: Silence normal tool output to stdout.
• -Z, --enable-errata: Enable the application of errata fixups. Useful if an errata fixup needs to be applied to commands sent to the TPM. Defining the environment TPM2TOOLS_ENABLE_ERRATA is equivalent.
• -R, --autoflush: Enable autoflush for transient objects created by the command. If a parent object is loaded from a context file also the transient parent object will be flushed. Autoflush can also be activated if the environment variable TPM2TOOLS_AUTOFLUSH is is set to yes or true. information many users may expect.

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:

1. The command line option -T or --tcti
2. The environment variable: TPM2TOOLS_TCTI.

Note: The command line option always overrides the environment variable.

The current known TCTIs are:

• tabrmd - The resource manager, called tabrmd (https://github.com/tpm2-software/tpm2-abrmd). Note that tabrmd and abrmd as a tcti name are synonymous.
• mssim - Typically used for communicating to the TPM software simulator.
• device - Used when talking directly to a TPM device file.
• none - Do not initalize a connection with the TPM. Some tools allow for off-tpm options and thus support not using a TCTI. Tools that do not support it will error when attempted to be used without a TCTI connection. Does not support ANY options and MUST BE presented as the exact text of “none”.

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.

This collection of options are used to configure the various known TCTI modules available:

• device: For the device TCTI, the TPM character device file for use by the device TCTI can be specified. The default is /dev/tpm0.

  Example: -T device:/dev/tpm0 or export TPM2TOOLS_TCTI=“device:/dev/tpm0”

• mssim: For the mssim TCTI, the domain name or IP address and port number used by the simulator can be specified. The default are 127.0.0.1 and 2321.

  Example: -T mssim:host=localhost,port=2321 or export TPM2TOOLS_TCTI=“mssim:host=localhost,port=2321”

• abrmd: For the abrmd TCTI, the configuration string format is a series of simple key value pairs separated by a `,' character. Each key and value string are separated by a `=' character.

  • TCTI abrmd supports two keys:

    1. `bus_name' : The name of the tabrmd service on the bus (a string).
    2. `bus_type' : The type of the dbus instance (a string) limited to `session' and `system'.

  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.

• The TPM requires that the name algorithm of the child be smaller than the parent.

Tools can return any of the following codes:

• 0 - Success.
• 1 - General non-specific error.
• 2 - Options handling error.
• 3 - Authentication error.
• 4 - TCTI related error.
• 5 - Non supported scheme. Applicable to tpm2_testparams.

Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)

See the Mailing List (https://lists.linuxfoundation.org/mailman/listinfo/tpm2)