NAME

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

SYNOPSIS

       tpm2_policynv [OPTIONS] [ARGUMENT] [ARGUMENT]

DESCRIPTION

       tpm2_policynv(1) - This command evaluates policy authorization by comparing  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 unsigned 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 >= unsigned 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

OPTIONS

       • -C, --hierarchy=OBJECT:

         Specifies the hierarchy used to authorize.  Supported options are:

         • o for TPM_RH_OWNER

         • p for TPM_RH_PLATFORM

         • <num> where a hierarchy handle or nv-index may be used.

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

       • -P, --auth=AUTH:

         Specifies the authorization value for the hierarchy.

       • -L, --policy=FILE:

         File to save the policy digest.

       • -S, --session=FILE:

         The  policy  session  file generated via the -S option to tpm2_startauthsession or saved
         off of a previous tool run.

       • --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.

       • --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.

       • -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 “-”.

   References

COMMON OPTIONS

       This collection of options are common to many programs and provide information  that  many
       users may expect.

       • -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 requested, the tool will provide errors from man on stderr.   If  the  “no-man”
         option if specified, or the manpager fails, the short options 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.

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

       • -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.

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

       • -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.  information 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 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

       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
              nv_test_index=0x01500001
              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 options.
              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 options.
              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

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.01.org/mailman/listinfo/tpm2)