csu3_am335x/EVSE/GPL/tpm2-tools-5.1/man/man1/tpm2_policyrestart.1

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.TH "tpm2_policyrestart" "1" "" "tpm2\-tools" "General Commands Manual"
.hy
.SH NAME
.PP
\f[B]tpm2_policyrestart\f[](1) \- Restart an existing session with the
TPM.
.SH SYNOPSIS
.PP
\f[B]tpm2_policyrestart\f[] [\f[I]OPTIONS\f[]]
.SH DESCRIPTION
.PP
\f[B]tpm2_policyrestart\f[](1) \- Restarts a session with the TPM back
to it\[aq]s initial state.
This is useful when the TPM gives one a \f[B]TPM_RC_PCR_CHANGED\f[]
(\f[C]0x00000128\f[]) error code when using a PCR policy session.
.PP
This will be returned if a PCR state affecting policy is altered during
the session.
One could restart the session and try again, however, the PCR state
would still need to satisfy the policy.
.SH OPTIONS
.IP \[bu] 2
\f[B]\-S\f[], \f[B]\-\-session\f[]=\f[I]FILE\f[]:
.RS 2
.PP
Optional, A session file from \f[B]tpm2_startauthsession\f[](1)\[aq]s
\f[B]\-S\f[] option.
This session is used in lieu of starting a session and using the PCR
policy options.
.RE
.SS References
.SH COMMON OPTIONS
.PP
This collection of options are common to many programs and provide
information that many users may expect.
.IP \[bu] 2
\f[B]\-h\f[], \f[B]\-\-help=[man|no\-man]\f[]: 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.
.RS 2
.PP
To successfully use the manpages feature requires the manpages to be
installed or on \f[I]MANPATH\f[], See man(1) for more details.
.RE
.IP \[bu] 2
\f[B]\-v\f[], \f[B]\-\-version\f[]: Display version information for this
tool, supported tctis and exit.
.IP \[bu] 2
\f[B]\-V\f[], \f[B]\-\-verbose\f[]: Increase the information that the
tool prints to the console during its execution.
When using this option the file and line number are printed.
.IP \[bu] 2
\f[B]\-Q\f[], \f[B]\-\-quiet\f[]: Silence normal tool output to stdout.
.IP \[bu] 2
\f[B]\-Z\f[], \f[B]\-\-enable\-errata\f[]: 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.
.SH TCTI Configuration
.PP
The TCTI or "Transmission Interface" is the communication mechanism with
the TPM.
TCTIs can be changed for communication with TPMs across different
mediums.
.PP
To control the TCTI, the tools respect:
.IP "1." 3
The command line option \f[B]\-T\f[] or \f[B]\-\-tcti\f[]
.IP "2." 3
The environment variable: \f[I]TPM2TOOLS_TCTI\f[].
.PP
\f[B]Note:\f[] The command line option always overrides the environment
variable.
.PP
The current known TCTIs are:
.IP \[bu] 2
tabrmd \- The resource manager, called
tabrmd (https://github.com/tpm2-software/tpm2-abrmd).
Note that tabrmd and abrmd as a tcti name are synonymous.
.IP \[bu] 2
mssim \- Typically used for communicating to the TPM software simulator.
.IP \[bu] 2
device \- Used when talking directly to a TPM device file.
.IP \[bu] 2
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 \f[I]ANY\f[] options and \f[I]MUST BE\f[] presented as
the exact text of "none".
.PP
The arguments to either the command line option or the environment
variable are in the form:
.PP
\f[C]<tcti\-name>:<tcti\-option\-config>\f[]
.PP
Specifying an empty string for either the \f[C]<tcti\-name>\f[] or
\f[C]<tcti\-option\-config>\f[] results in the default being used for
that portion respectively.
.SS TCTI Defaults
.PP
When a TCTI is not specified, the default TCTI is searched for using
\f[I]dlopen(3)\f[] semantics.
The tools will search for \f[I]tabrmd\f[], \f[I]device\f[] and
\f[I]mssim\f[] TCTIs \f[B]IN THAT ORDER\f[] and \f[B]USE THE FIRST ONE
FOUND\f[].
You can query what TCTI will be chosen as the default by using the
\f[B]\-v\f[] option to print the version information.
The "default\-tcti" key\-value pair will indicate which of the
aforementioned TCTIs is the default.
.SS Custom TCTIs
.PP
Any TCTI that implements the dynamic TCTI interface can be loaded.
The tools internally use \f[I]dlopen(3)\f[], and the raw
\f[I]tcti\-name\f[] value is used for the lookup.
Thus, this could be a path to the shared library, or a library name as
understood by \f[I]dlopen(3)\f[] semantics.
.SH TCTI OPTIONS
.PP
This collection of options are used to configure the various known TCTI
modules available:
.IP \[bu] 2
\f[B]device\f[]: For the device TCTI, the TPM character device file for
use by the device TCTI can be specified.
The default is \f[I]/dev/tpm0\f[].
.RS 2
.PP
Example: \f[B]\-T device:/dev/tpm0\f[] or \f[B]export
\f[I]TPM2TOOLS_TCTI\f[]="device:/dev/tpm0"\f[]
.RE
.IP \[bu] 2
\f[B]mssim\f[]: 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.
.RS 2
.PP
Example: \f[B]\-T mssim:host=localhost,port=2321\f[] or \f[B]export
\f[I]TPM2TOOLS_TCTI\f[]="mssim:host=localhost,port=2321"\f[]
.RE
.IP \[bu] 2
\f[B]abrmd\f[]: For the abrmd TCTI, the configuration string format is a
series of simple key value pairs separated by a \[aq],\[aq] character.
Each key and value string are separated by a \[aq]=\[aq] character.
.RS 2
.IP \[bu] 2
TCTI abrmd supports two keys:
.RS 2
.IP "1." 3
\[aq]bus_name\[aq] : The name of the tabrmd service on the bus (a
string).
.IP "2." 3
\[aq]bus_type\[aq] : The type of the dbus instance (a string) limited to
\[aq]session\[aq] and \[aq]system\[aq].
.RE
.PP
Specify the tabrmd tcti name and a config string of
\f[C]bus_name=com.example.FooBar\f[]:
.PP
\f[C]\\\-\-tcti=tabrmd:bus_name=com.example.FooBar\f[]
.PP
Specify the default (abrmd) tcti and a config string of
\f[C]bus_type=session\f[]:
.PP
\f[C]\\\-\-tcti:bus_type=session\f[]
.PP
\f[B]NOTE\f[]: abrmd and tabrmd are synonymous.
the various known TCTI modules.
.RE
.SH EXAMPLES
.SS Start a \f[I]policy\f[] session and restart it, unsealing some data.
.IP
.nf
\f[C]
#\ create\ a\ policy\ and\ bind\ it\ to\ an\ object
tpm2_startauthsession\ \-S\ session.dat

tpm2_policypcr\ \-S\ session.dat\ \-l\ "sha1:0,1,2,3"\ \-L\ policy.dat

tpm2_createprimary\ \-c\ primary.ctx

tpm2_create\ \-Cprimary.ctx\ \-u\ key.pub\ \-r\ key.priv\ \-L\ policy.dat\ \-i\-\ <<<\ "secret"

tpm2_load\ \-C\ primary.ctx\ \-c\ key.ctx\ \-u\ key.pub\ \-r\ key.priv

tpm2_flushcontext\ session.dat

#\ satisfy\ the\ policy\ and\ use\ the\ object
tpm2_startauthsession\ \-\-policy\ \-S\ session.dat

tpm2_policypcr\ \-S\ session.dat\ \-l\ "sha1:0,1,2,3"

#\ PCR\ event\ occurs\ here\ causing\ unseal\ to\ fail
tpm2_pcrevent\ 0\ <<<\ "event\ data"

tpm2_unseal\ \-psession:session.dat\ \-c\ key.ct
ERROR:\ Esys_Unseal(0x128)\ \-\ tpm:error(2.0):\ PCR\ have\ changed\ since\ checked

#\ Clear\ the\ policy\ digest\ to\ initial\ state,\ note\ access\ to\ object\ no\ longer\ allowed\ by
#\ policy\ so\ policyor\ would\ be\ useful\ here.
tpm2_policyrestart\ \-S\ session.dat
\f[]
.fi
.SH Returns
.PP
Tools can return any of the following codes:
.IP \[bu] 2
0 \- Success.
.IP \[bu] 2
1 \- General non\-specific error.
.IP \[bu] 2
2 \- Options handling error.
.IP \[bu] 2
3 \- Authentication error.
.IP \[bu] 2
4 \- TCTI related error.
.IP \[bu] 2
5 \- Non supported scheme.
Applicable to tpm2_testparams.
.SH Limitations
.PP
It expects a session to be already established via
\f[B]tpm2_startauthsession\f[](1) and requires one of the following:
.IP \[bu] 2
direct device access
.IP \[bu] 2
extended session support with \f[B]tpm2\-abrmd\f[].
.PP
Without it, most resource managers \f[B]will not\f[] save session state
between command invocations.
.SH BUGS
.PP
Github Issues (https://github.com/tpm2-software/tpm2-tools/issues)
.SH HELP
.PP
See the Mailing List (https://lists.01.org/mailman/listinfo/tpm2)