Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
tpm2_nvundefine(1)	    General Commands Manual	    tpm2_nvundefine(1)

       tpm2_nvundefine(1) - Delete a Non-Volatile (NV) index.

       tpm2_nvundefine [OPTIONS] [ARGUMENT]

       tpm2_nvundefine(1)  - Deletes a Non-Volatile (NV) index that was	previ-
       ously defined with tpm2_nvdefine(1).  The index is specified as an  ar-
       gument.	It can be specified as raw handle or an	offset value to	the nv
       handle range "TPM2_HR_NV_INDEX".

       The tool	is also	capable	of deleting  NV	 indices  with	attribute  TP-
       MA_NV_POLICY_DELETE,  and  the tool uses	this attribute for the default
       hierarchy to select when	-C is missing.	The default value  for	-C  is
       the  "owner"  hierarchy	when TPMA_NV_POLICY_DELETE is clear and	"plat-
       form" when TPMA_NV_POLICY_DELETE	is set.

       o -C, --hierarchy=OBJECT:
	 Specifies the hierarchy used to authorize.  Supported options are:

	 o o for TPM_RH_OWNER


	 o <num> where a hierarchy handle may be specified.

       +o -P, --auth=AUTH:

	 Specifies the authorization value for the hierarchy.

       o -S, --session=POLICY_SESSION:

	 Specify a policy session to use when the NV index has	attribute  TP-

       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 NV index or	offset

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-

       Passwords  are  interpreted  in	the following forms below using	prefix

       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 au-


       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.


       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

	      #	to use a file from a path

	      #	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).  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.

       To use a	session	context	file called session.ctx.


       To use a	session	context	file called session.ctx	AND send the authvalue


       To use a	session	context	file called session.ctx	AND send the HEX auth-
       value 0x11223344.


   PCR Authorizations
       You can satisfy a PCR policy using the "pcr:" prefix and	the PCR	 mini-
       language.       The     PCR     minilanguage	is     as     follows:

       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/

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


       specifying AUTH.

       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-

       The current known TCTIs are:

       o tabrmd	     -	   The	   resource	manager,     called	tabrmd
	 (	 Note that tabrmd  and
	 abrmd as a tcti name are synonymous.

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

       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:


       Specifying  an  empty  string  for  either the <tcti-name> or <tcti-op-
       tion-config> results in the default being used for that portion respec-

   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.

       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-

       _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 and 2321.

	 Example: -T mssim:host=localhost,port=2321  or	 export	 TPM2TOOLS_TC-

       _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

	   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-


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


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

   Define an ordinary NV index and delete it
	      tpm2_nvdefine 1

	      tpm2_nvundefine 1

   Define an ordinary NV index with attribute
       TPMA_NV_POLICY_DELETE and delete	it

	      tpm2_startauthsession -S s.ctx

	      tpm2_policyauthvalue -S s.ctx

	      tpm2_policycommandcode -S	s.ctx -L policy.dat TPM2_CC_NV_UndefineSpaceSpecial

	      tpm2_nvdefine -C p -s 32 \
		-a "ppread|ppwrite|authread|authwrite|platformcreate|policydelete|write_stclear|read_stclear" \
		-L policy.dat 1

	      tpm2_flushcontext	s.ctx

	      tpm2_startauthsession --policy-session -S	s.ctx

	      tpm2_policyauthvalue -S s.ctx

	      tpm2_policycommandcode -S	s.ctx TPM2_CC_NV_UndefineSpaceSpecial

	      tpm2_nvundefine -S s.ctx 1

       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.

       Github Issues (

       See the Mailing List (

tpm2-tools						    tpm2_nvundefine(1)

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

Want to link to this manual page? Use this URL:

home | help