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tpm2_clear(1)		    General Commands Manual		 tpm2_clear(1)

NAME
       tpm2_clear(1)  -	Clears lockout,	endorsement and	owner hierarchy	autho-
       rization	values.

SYNOPSIS
       tpm2_clear [OPTIONS] [ARGUMENT]

DESCRIPTION
       tpm2_clear(1) - Send a clear command to the TPM to clear	the 3  hierar-
       chy  authorization values.  As an argument takes	the auth value for ei-
       ther platform or	lockout	hierarchy

       NOTE: All objects created under the respective hierarchies are lost.

OPTIONS
       o -c, --auth-hierarchy=OBJECT:

	 Specifies the hierarchy the tools should operate on.  By  default  it
	 operates on the lockout hierarchy.

	 NOTE  :  Operating on platform	hierarchy require platform authentica-
	 tion.

       o --cphash=FILE

	 File path to record the hash of the command parameters.  This is com-
	 monly termed as cpHash.  NOTE:	When this option is selected, The tool
	 will not actually execute the command,	it simply returns a cpHash.

       o ARGUMENT the command line argument specifies the AUTH to be  set  for
	 the object specified with -c.

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

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

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

	 o owner: the owner hierarchy

	 o platform: the platform hierarchy

	 o endorsement:	the endorsement	hierarchy

	 o lockout: the	lockout	control	persistent object

       o 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 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	speci-
       fied".

   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 au-
       thorization.

   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:0x1122334455667788

   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).  Option-
       ally, 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 auth-
       value 0x11223344.

	      session:session.ctx+hex:11223344

   PCR Authorizations
       You  can	satisfy	a PCR policy using the "pcr:" prefix and the PCR mini-
       language.      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 the output of the raw PCR contents as
       returned	by tpm2_pcrread(1).

       PCR bank	specifiers (common/pcr.md)

   Examples
       To satisfy a PCR	policy of sha256 on banks 0, 1,	2 and 3	use a specifi-
       er of:

	      pcr:sha256:0,1,2,3

       specifying AUTH.

COMMON OPTIONS
       This  collection	of options are common to many programs and provide in-
       formation that many users may expect.

       o -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 re-
	 quested, the tool will	provide	errors from man	 on  stderr.   If  the
	 "no-man"  option  if  specified, or the manpager fails, the short op-
	 tions 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.

       o -v,  --version:  Display version information for this tool, supported
	 tctis and exit.

       o -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.

       o -Q, --quiet: Silence normal tool output to stdout.

       o -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.   in-
	 formation many	users may expect.

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 vari-
       able.

       The current known TCTIs are:

       o tabrmd	    -	  The	  resource     manager,	    called	tabrmd
	 (https://github.com/tpm2-software/tpm2-abrmd).	  Note that tabrmd and
	 abrmd as a tcti name are synonymous.

       o mssim - Typically used	for communicating to the TPM software  simula-
	 tor.

       o device	- Used when talking directly to	a TPM device file.

       o 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-op-
       tion-config> results in the default being used for that portion respec-
       tively.

   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	 indi-
       cate 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 li-
       brary name as understood	by dlopen(3) semantics.

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

       o 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="de-
	 vice:/dev/tpm0"

       _o 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_TC-
	 TI="mssim:host=localhost,port=2321"

       _o abrmd:	For the	abrmd TCTI, the	configuration string format is	a  se-
	 ries  of  simple  key value pairs separated by	a ',' character.  Each
	 key and value string are separated by a '=' character.

	 o 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.ex-
	 ample.FooBar:

	 \--tcti=tabrmd:bus_name=com.example.FooBar

	 Specify the default (abrmd) tcti and a	config string of bus_type=ses-
	 sion:

	 \--tcti:bus_type=session

	 NOTE: abrmd and tabrmd	are synonymous.	 the various known  TCTI  mod-
	 ules.

EXAMPLES
   Set owner, endorsement and lockout authorizations to	an empty value
	      tpm2_clear lockoutpasswd

   Clear the authorization values on the platform hierarchy
	      tpm2_clear -c p

Returns
       Tools can return	any of the following codes:

       o 0 - Success.

       o 1 - General non-specific error.

       o 2 - Options handling error.

       o 3 - Authentication error.

       o 4 - TCTI related error.

       o 5 - Non supported scheme.  Applicable to tpm2_testparams.

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

HELP
       See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)

tpm2-tools							 tpm2_clear(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | Context Object Format | Authorization Formatting | COMMON OPTIONS | TCTI Configuration | TCTI OPTIONS | EXAMPLES | Returns | BUGS | HELP

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