tpm2_changeeps(1) - Replaces the active endorsement primary seed with a new one generated off the TPM2

       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 EMPTYPASSWORD when not specified”.

   Passwords
       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.

   String
       A  string  password, specified by prefix “str:” or it’s absence (raw string without prefix) is not inter‐
       preted, and is directly used for authorization.

   Examples
              foobar
              str:foobar

   Hex-string
       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.

   Example
              hex:1122334455667788

   File
       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.

   Examples
              # 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

   Sessions
       When  using  a policy session to authorize the use of an object, prefix the option argument with the ses‐sion 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 pass‐
       word), then append a + and a string as described in the Passwords section.

   Examples
       To use a session context file called session.ctx.

              session:session.ctx

       To use a session context file called session.ctxAND send the authvalue mypassword.

              session:session.ctx+mypassword

       To use a session context file called session.ctxAND send the HEX authvalue 0x11223344.

              session:session.ctx+hex:11223344

   PCRAuthorizations
       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

   Examples
       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.

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

tpm2_changeeps(1) - Replaces the active endorsement primary seed with a new one generated  off  the  TPM2
       RNG.   The  Transient  and Persistent objects under the endorsement hierarchy are lost.  This command re‐
       quires platform auth.

ChangetheendorsementprimaryseedwheretheplatformauthisNULL.
              tpm2_changeeps

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

tpm2-tools                                                                                     tpm2_changeeps(1)

       It  expects a session to be already established via tpm2_startauthsession(1) and requires one of the fol‐
       lowing:

       • direct device access

       • extended session support with tpm2-abrmd.

       Without it, most resource managers willnot save session state between command invocations.

tpm2_changeeps(1)  -  Replaces  the active endorsement primary seed with a new one generated off the TPM2
       RNG.

       • -p, --auth=AUTH

         Specifies the AUTH for the platform.  hierarchy.

       • --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,
         unless rphash is also required.

       • --rphash=FILE

         File path to record the hash of the response parameters.  This is commonly termed as rpHash.

       • -S, --session=FILE:

         The  session created using tpm2_startauthsession.  This can be used to specify an auxiliary session for
         auditing and or encryption/decryption of the parameters.

   References

       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.

tpm2_changeeps [OPTIONS]

       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  sup‐
         port not using a TCTI.  Tools that do not support it will error when attempted to be used without a TC‐
         TI connection.  Does not support ANY options and MUSTBE 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 be‐
       ing used for that portion respectively.

   TCTIDefaults
       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 INTHATORDER and USETHEFIRSTONEFOUND.  You can query  what
       TCTI  will  be  chosen  as the default by using the -v option to print the version information.  The “de‐
       fault-tcti” key-value pair will indicate which of the aforementioned TCTIs is the default.

   CustomTCTIs
       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:

       • 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: -Tdevice:/dev/tpm0 or exportTPM2TOOLS_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: -Tmssim:host=localhost,port=2321 or exportTPM2TOOLS_TCTI=“mssim:host=localhost,port=2321”

       • abrmd: For the abrmd TCTI, the configuration string format is a series of simple key value pairs  sepa‐
         rated 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.