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tpm2_policycphash(1) General Commands Manual tpm2_policycphash(1) NAME tpm2_policycphash(1) - Couples a policy with command parameters of the command. SYNOPSIS tpm2_policycphash [OPTIONS] DESCRIPTION tpm2_policycphash(1) - Couples a policy with command parameters of the command. This is a deferred assertion where the hash of the command parameters in a TPM command is checked against the one specified in the policy. OPTIONS • -L, --policy=FILE: File to save the compounded policy digest. • -S, --session=FILE: The policy session file generated via the -S option to tpm2_star- tauthsession(1). • --cphash-input=FILE: The file containing the command parameter hash of the command. • --cphash=FILE: DEPRECATED, use -cphash-input instead. References COMMON OPTIONS This collection of options are common to many programs and provide in- formation 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 re- quested, the tool will provide errors from man on stderr. If the "no-man" option if specified, or the manpager fails, the short op- tions 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. in- formation 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 vari- able. 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 simula- tor. • 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 respective- ly. 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 indi- cate 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 li- brary 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="de- vice:/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_TC- TI="mssim:host=localhost,port=2321" • abrmd: For the abrmd TCTI, the configuration string format is a se- ries 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.ex- ample.FooBar: \--tcti=tabrmd:bus_name=com.example.FooBar Specify the default (abrmd) tcti and a config string of bus_type=ses- sion: \--tcti:bus_type=session NOTE: abrmd and tabrmd are synonymous. the various known TCTI mod- ules. EXAMPLES Restrict the value that can be set through tpm2_nvsetbits. Define NV index object with authorized policy openssl genrsa -out signing_key_private.pem 2048 openssl rsa -in signing_key_private.pem -out signing_key_public.pem -pubout tpm2_loadexternal -G rsa -C o -u signing_key_public.pem -c signing_key.ctx \ -n signing_key.name tpm2_startauthsession -S session.ctx -g sha256 tpm2_policyauthorize -S session.ctx -L authorized.policy -n signing_key.name tpm2_flushcontext session.ctx tpm2_nvdefine 1 -a "policywrite|authwrite|ownerread|nt=bits" -L authorized.policy Create policycphash tpm2_nvsetbits 1 -i 1 --cphash cp.hash tpm2_startauthsession -S session.ctx -g sha256 tpm2_policycphash -S session.ctx -L policy.cphash --cphash cp.hash tpm2_flushcontext session.ctx Sign and verify policycphash openssl dgst -sha256 -sign signing_key_private.pem \ -out policycphash.signature policy.cphash tpm2_verifysignature -c signing_key.ctx -g sha256 -m policy.cphash \ -s policycphash.signature -t verification.tkt -f rsassa Satisfy policycphash and execute nvsetbits tpm2_startauthsession -S session.ctx --policy-session -g sha256 tpm2_policycphash -S session.ctx --cphash cp.hash tpm2_policyauthorize -S session.ctx -i policy.cphash -n signing_key.name \ -t verification.tkt tpm2_nvsetbits 1 -i 1 -P "session:session.ctx" 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_startauthses- sion(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.linuxfoundation.org/mailman/listin- fo/tpm2) tpm2-tools tpm2_policycphash(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | COMMON OPTIONS | TCTI Configuration | TCTI OPTIONS | EXAMPLES | Returns | Limitations | BUGS | HELP
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