Provided by: tpm2-tools_5.4-1_amd64 bug

NAME

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

SYNOPSIS

       tpm2_changeeps [OPTIONS]

DESCRIPTION

       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 requires platform auth.

OPTIONS

-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

Authorization Formatting

       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
       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 interpreted, 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  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.

   Examples
       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

   PCR Authorizations
       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.

TCTI Configuration

       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.

   TCTI Defaults
       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.

   Custom TCTIs
       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.

TCTI OPTIONS

       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.

EXAMPLES

   Change the endorsement primary seed where the platform auth is NULL.
              tpm2_changeeps

Returns

       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.

Limitations

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

       • direct device access

       • extended session support with tpm2-abrmd.

       Without   it,  most  resource  managers  will  not  save  session  state  between  command
       invocations.

BUGS

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

HELP

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