Configuring DBus session using TPM2TSS_TCTI environment variable

[abdawoud]

Hi,

TPM2TOOLS_TCTI and TPM2OPENSSL_TCTI work just fine to configure usage of session DBus, is there a TPM2TSS_TCTI equivalent?

e.g., export TPM2TSS_TCTI=tabrmd:bus_name=com.intel.tss2.Tabrmd,bus_type=session

Thank you!

[joholl]

Not really.

The System API is not smart like that. You pass a certain TCTI context to Tss2_Sys_Initialize() call and that's it.

tpm2-tss/src/tss2-sys/api/Tss2_Sys_Initialize.c

Lines 30 to 39 in 8699ab3

	TSS2_RC Tss2_Sys_Initialize(
	TSS2_SYS_CONTEXT *sysContext,
	size_t contextSize,
	TSS2_TCTI_CONTEXT *tctiContext,
	TSS2_ABI_VERSION *abiVersion)
	{
	_TSS2_SYS_CONTEXT_BLOB *ctx = syscontext_cast(sysContext);
	if (!ctx || !tctiContext)
	return TSS2_SYS_RC_BAD_REFERENCE;

The Enhanced System API is much more smart. It uses tctildr, but that does not support environment variables, afaik.

tpm2-tss/src/tss2-esys/esys_context.c

Lines 22 to 46 in 8699ab3

	/** Initialize an ESYS_CONTEXT for further use.
	*
	* Initialize an ESYS_CONTEXT that holds all the state and metadata information
	* during an interaction with the TPM.
	* If not specified, load a TCTI in this order:
	* Library libtss2-tcti-default.so (link to the preferred TCTI)
	* Library libtss2-tcti-tabrmd.so (tabrmd)
	* Device /dev/tpmrm0 (kernel resident resource manager)
	* Device /dev/tpm0 (hardware TPM)
	* TCP socket localhost:2321 (TPM simulator)
	* @param esys_context [out] The ESYS_CONTEXT.
	* @param tcti [in] The TCTI context used to connect to the TPM (may be NULL).
	* @param abiVersion [in,out] The abi version to check and the abi version
	* supported by this implementation (may be NULL).
	* @retval TSS2_ESYS_RC_SUCCESS if the function call was a success.
	* @retval TSS2_ESYS_RC_BAD_REFERENCE if esysContext is NULL.
	* @retval TSS2_ESYS_RC_MEMORY if the ESAPI cannot allocate enough memory to
	* create the context.
	* @retval TSS2_RCs produced by lower layers of the software stack may be
	* returned to the caller unaltered unless handled internally.
	*/
	TSS2_RC
	Esys_Initialize(ESYS_CONTEXT ** esys_context, TSS2_TCTI_CONTEXT * tcti,
	TSS2_ABI_VERSION * abiVersion)
	{

The Feature API is configured via its config file. Here, you could set the path of the config file via the env variable TSS2_FAPICONF.

tpm2-tss/doc/fapi-config.md

Line 10 in 8699ab3

* tcti: The TCTI interface which will be used.

The tests can be configured via the env. variable TPM20TEST_TCTI_NAME, but i assume that is not what you're looking for.