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

FreeBSD Manual Pages


home | help
tpm2_policynv(1)	    General Commands Manual	      tpm2_policynv(1)

       tpm2_policynv(1)	- Evaluates policy authorization by comparing a	speci-
       fied value against the contents in the specified	NV Index.

       tpm2_policynv [OPTIONS] [ARGUMENT] [ARGUMENT]

       tpm2_policynv(1)	- This command evaluates policy	authorization by  com-
       paring the contents written to an NV index against the one specified in
       the tool	options.  The tool takes two arguments	-  (1)	The  NV	 index
       specified  as  raw  handle  or  an  offset value	to the nv handle range
       "TPM2_HR_NV_INDEX" and (2) Comparison operator for magnitude comparison
       and  or bit test	operations.  In	the specification the NV index holding
       the data	is called operandA and the data	that  the  user	 specifies  to
       compare	is  called operandB.  The comparison operator can be specified
       as follows: * "eq" if operandA  =  operandB  *  "neq"  if  operandA  !=
       operandB	 *  "sgt"  if signed operandA >	signed operandB	* "ugt"	if un-
       signed operandA > unsigned operandB * "slt" if signed operandA <	signed
       operandB	 *  "ult"  if unsigned operandA	< unsigned operandB * "sge" if
       signed operandA >= signed operandB * "uge" if unsigned operandA >=  un-
       signed operandB * "sle" if signed operandA <= unsigned operandB * "ule"
       if unsigned operandA <= unsigned	operandB * "bs"	if  all	 bits  set  in
       operandA	 are  set  in  operandB	* "bc" if all bits set in operandA are
       clear in	operandB

       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 or nv-index may be used.

	 When -C isn't explicitly passed the index handle will be used to  au-
	 thorize  against  the	index.	The index auth value is	set via	the -p
	 option	to tpm2_nvdefine(1).

       o -P, --auth=AUTH:

	 Specifies the authorization value for the hierarchy.

       o -L, --policy=FILE:

	 File to save the policy digest.

       o -S, --session=FILE:

	 The policy session file generated via the  -S	option	to  tpm2_star-
	 tauthsession or saved off of a	previous tool run.

       o --offset=NATURAL_NUMBER:

	 The  offset  within  the NV index to start comparing at.  The size of
	 the data starting at offset and ending	at size	of NV index shall  not
	 exceed	the size of the	operand	specified in the options.

       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 -i, --input=FILE:

	 Specifies  the	 input file with data to compare to NV Index contents.
	 In the	standard specification,	this is	termed as operand or  operandB
	 more  specifically .  It can be specified as a	file input or stdin if
	 option	value is a "-".

       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-

       Test if NV index	content	value is equal to an input number.  To do this
       we  first  create  an  NV  index	of size	1 byte and write a value.  Eg.
       0xAA.  Next we attempt to create	a policy that  becomes	valid  if  the
       equality	 comparison  operation of the NV index content against the one
       specified in the	tool options.

   Define the test NV Index and	write the value	0xAA to	it
	      tpm2_nvdefine -C o -p nvpass $nv_test_index -a "authread|authwrite" -s 1
	      echo "aa"	| xxd -r -p | tpm2_nvwrite -P nvpass -i- $nv_test_index

   Attempt defining policynv with wrong	comparison value specified in

	      tpm2_startauthsession -S session.ctx --policy-session
	      ### This should fail
	      echo 0xBB	| tpm2_policynv	-S session.ctx -L policy.nv -i-	0x1500001 eq -P	nvpass
	      tpm2_flushcontext	session.ctx

   Attempt defining policynv with right	comparison value specified in

	      tpm2_startauthsession -S session.ctx --policy-session
	      ### This should pass
	      echo 0xAA	| tpm2_policynv	-S session.ctx -L policy.nv -i-	0x1500001 eq -P	nvpass
	      tpm2_flushcontext	session.ctx

       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.

       It expects a session to be already established  via  tpm2_startauthses-
       sion(1) and requires one	of the following:

       o direct	device access

       o extended session support with tpm2-abrmd.

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

       Github Issues (

       See the Mailing List (

tpm2-tools						      tpm2_policynv(1)


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

home | help