NAME

       tpm2_getcap(1) - Display TPM capabilities in a human readable form.

SYNOPSIS

       tpm2_getcap [OPTIONS] [CAPABILITY]

DESCRIPTION

       tpm2_getcap(1)  -  Query  the TPM for it’s capabilities / properties and print them to the
       console.  It takes a string form of the capability to query as an argument  to  the  tool.
       Currently supported capability groups are:

       • algorithms: Display data about supported algorithms.

       • commands: Display data about supported commands.

       • pcrs: Display currently allocated PCRs.

       • properties-fixed: Display fixed TPM properties.

       • properties-variable: Display variable TPM properties.

       • ecc-curves: Display data about elliptic curves.

       • handles-transient: Display handles about transient objects.

       • handles-persistent: Display handles about persistent objects.

       • handles-permanent: Display handles about permanent objects.

       • handles-pcr: Display handles about PCRs.

       • handles-nv-index: Display handles about NV Indices.

       • handles-loaded-session: Display handles about both loaded HMAC and policy sessions.

       • handles-saved-session: Display handles about saved sessions.

       • vendor[:num]:  Displays  the  vendor  properties  as  a  hex  buffer output.  The string
         “vendor” can be suffixed with a colon followed by a number as understood  by  strtoul(3)
         with a 0 base.  That value is used as the property value within the
       TPM2_GetCapability  command,  and  defaults  to  1.  An example to call it with a property
       value of 2 is: tpm2_getcap vendor:2

         NOTE: if vendor requests hang, try the “-i” option to ignore the moreData field and only
         read once.

OPTIONS

       • -l, --list:

         List  known  supported capability names.  These names can be supplied as the argument to
         the -c option.  Output is in a YAML compliant list to stdout.

         For example:

                  - algorithms
                  - commands
                  - properties-fixed
                  ...

       • --ignore-moredata

       Ignores the moreData field when dealing with buggy TPM responses.

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.

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.

EXAMPLES

   To list the fixed properties of the TPM
              tpm2_getcap properties-fixed

   To list the supported capability groups
              tpm2_getcap -l

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.

BUGS

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

HELP

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