NAME

       tpm2_stirrandom(1) - Add “additional information” into TPM RNG state.

SYNOPSIS

       tpm2_stirrandom [OPTIONS] [ARGUMENT]

DESCRIPTION

       tpm2_stirrandom(1)  -  Inject “additional information” as bytes into TPM entropy Protected
       Capability pool.

       “Additional information” can be extracted from file specified as argument  or  being  read
       from STDIN if argument is not specified.

       Up to 128 bytes can be injected at once through standard input to tpm2_stirrandom(1).

       If input file is larger than 128 bytes, tpm2_stirrandom(1) will fail.

       Adding  data  through  tpm2_stirrandom(1)  will  trigger a reseeding of TPM DRBG Protected
       Capability.  It is used when performing any sensitive action on a shielded  location  such
       as  loading  a  persistent  key  or  acting  on  a  Protected Capability like updating TPM
       firmware.

OPTIONS

       This command has no option

   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.

       • -R,  --autoflush:  Enable  autoflush for transient objects created by the command.  If a
         parent object is loaded from a context file also the transient  parent  object  will  be
         flushed.     Autoflush   can   also   be   activated   if   the   environment   variable
         TPM2TOOLS_AUTOFLUSH is is set to yes or true.  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

   Inject from stdin using echo
              echo -n "myrandomdata" | tpm2_stirrandom

   Inject 64 bytes from stdin using a file
              dd if=/dev/urandom bs=1 count=64 > myrandom.bin

              tpm2_stirrandom < ./myrandom.bin

   Inject bytes from a file and reading up to 128 bytes
              dd if=/dev/urandom of=./myrandom.bin bs=1 count=42

              tpm2_stirrandom ./myrandom.bin

NOTES

       Please be aware that even if the “additional information” added by tpm2_stirrandom(1)  can
       be  entropy  gathered  from  other  DRBG sources, the TPM has no way of determining if the
       value has any entropy or not.  As a consequence, it will just be considered as “additional
       input”.

       The      “additional      input”      is      as     defined     in     NIST     SP800-90A
       (https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-90.pdf)

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)