| 1 | =head1 NAME
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| 2 |
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| 3 | TPMLIB_SetState - Set the TPM's volatile, permanent, or save state
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| 4 |
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| 5 | TPMLIB_GetState - Get the TPM's volatile, permanent, or save state
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| 6 |
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| 7 | =head1 LIBRARY
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| 8 |
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| 9 | TPM library (libtpms, -ltpms)
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| 10 |
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| 11 | =head1 SYNOPSIS
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| 12 |
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| 13 | B<#include <libtpms/tpm_library.h>>
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| 14 |
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| 15 | B<TPM_RESULT TPMLIB_SetState(enum TPMLIB_StateType st,
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| 16 | const unsigned char *buffer, uint32_t buflen);>
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| 17 |
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| 18 | B<TPM_RESULT TPMLIB_GetState(enum TPMLIB_StateType st,
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| 19 | unsigned char **buffer, uint32_t *buflen);>
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| 20 |
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| 21 | =head1 DESCRIPTION
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| 22 |
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| 23 | The B<TPMLIB_SetState()> function allows to set either one of the state blobs of
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| 24 | the TPM. The passed state blob is tested for whether it can be accepted and a TPM
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| 25 | error code is returned in case it cannot be accepted. In case of acceptance, the
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| 26 | state blob will be passed to the TPM upon B<TPM_MainInit()>. Setting a state blob
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| 27 | hides a file that may contain the same type of blob and would be read otherwise.
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| 28 | It is required to call this function with a NULL pointer for the buffer parameter
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| 29 | to hide a state blob in a file.
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| 30 |
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| 31 | It is only possible to set the state blobs after B<TPMLIB_ChooseTPMVersion()>
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| 32 | has been called. All state blobs are cleared when a different version of TPM is
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| 33 | chosen using B<TPMLIB_ChooseTPMVersion> or when a call to B<TPMLIB_SetState()>
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| 34 | fails because a state blob could not be accepted.
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| 35 |
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| 36 | The order in which state blobs are set is important. The first state blob has
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| 37 | to be the one representing the TPM's permanent state. Only after that either
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| 38 | the volatile or save state blobs can be set.
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| 39 |
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| 40 | The B<TPMLIB_GetState()> function allows to get the current state of the TPM.
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| 41 | For as long as the TPM has not been started, this function either returns the state
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| 42 | blob previously set with B<TPMLIB_SetState()> or the state is read from a file.
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| 43 | Once the TPM has been start the state of the running TPM is returned.
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| 44 |
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| 45 | The B<TPMLIB_STATE_SAVE_STATE> (save state) type of TPM state can be set with this
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| 46 | function. The same state blob will be returned until TPM_Startup(ST_STATE) has been
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| 47 | called, after which an empty blob will be returned. This blob can also only be
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| 48 | read after TPM_SaveState() has been sent to the TPM.
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| 49 |
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| 50 | =head1 SEE ALSO
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| 51 |
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| 52 | B<TPMLIB_ChooseTPMVersion>(3), B<TPMLIB_MainInit>(3), B<TPMLIB_Terminate>(3)
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| 53 |
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| 54 | =cut
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