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tpm2_pcrreset(1)	     General Commands Manual		tpm2_pcrreset(1)

NAME
     tpm2_pcrreset(1) - Reset one or more PCR banks

SYNOPSIS
     tpm2_pcrreset [OPTIONS] PCR_INDEX ...

DESCRIPTION
     tpm2_pcrreset(1)  - Reset PCR value in all banks for specified index.  More
     than one PCR index can be specified.

     The reset value is manufacturer-dependent and is either sequence of  00  or
     FF on the length of the hash algorithm for each supported bank.

     PCR_INDEX is a space separated list of PCR indexes to be reset when issuing
     the command.

OPTIONS
     This tool accepts no tool specific 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.

COMMON OPTIONS
     This collection of options are common to many programs and provide informa-
     tion that many users may expect.

     * -h, --help=[man|no-man]: Display the tools manpage.  By default,  it  at-
       tempts to invoke the manpager for the tool, however, on failure will out-
       put  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 speci-
       fied, or the manpager fails, the short options will be output to stdout.

       To  successfully use the manpages feature requires the manpages to be in-
       stalled 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  con-
       sole during its execution.  When using this option the file and line num-
       ber 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.   Defin-
       ing 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  connec-
       tion.   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-con-
     fig> 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.exam-
       ple.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
   Reset a single PCR
	    tpm2_pcrreset 23

   Reset multiple PCRs
	    tpm2_pcrreset 16 23

NOTES
     On  operating  system's locality (generally locality 0), only PCR 23 can be
     reset.  PCR-16 can also be reset on this locality, depending on  TPM  manu-
     facturers which could define this PCR as resettable.

     PCR  0  to  15  are  not resettable (being part of SRTM).	PCR 16 to 22 are
     mostly reserved for DRTM or dedicated to specific localities and might  not
     be resettable depending on current TPM locality.

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/mail-
     man/listinfo/tpm2)

tpm2-tools							tpm2_pcrreset(1)

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