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/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Functions for querying, manipulating and locking rollback indices
* stored in the TPM NVRAM.
*/
#ifndef ANTIROLLBACK_H_
#define ANTIROLLBACK_H_
#include "tpm_lite/tss_constants.h"
struct vb2_context;
/* TPM NVRAM location indices. */
#define FIRMWARE_NV_INDEX 0x1007
#define KERNEL_NV_INDEX 0x1008
/* This is just an opaque space for backup purposes */
#define BACKUP_NV_INDEX 0x1009
/* Structure definitions for TPM spaces */
/* Flags for firmware space */
/*
* Last boot was developer mode. TPM ownership is cleared when transitioning
* to/from developer mode.
*/
#define FLAG_LAST_BOOT_DEVELOPER 0x01
/* All functions return TPM_SUCCESS (zero) if successful, non-zero if error */
uint32_t antirollback_read_space_firmware(struct vb2_context *ctx);
/**
* Write may be called if the versions change.
*/
uint32_t antirollback_write_space_firmware(struct vb2_context *ctx);
/**
* Lock must be called.
*/
uint32_t antirollback_lock_space_firmware(void);
/****************************************************************************/
/*
* The following functions are internal apis, listed here for use by unit tests
* only.
*/
/**
* Issue a TPM_Clear and reenable/reactivate the TPM.
*/
uint32_t tpm_clear_and_reenable(void);
/**
* Like tlcl_write(), but checks for write errors due to hitting the 64-write
* limit and clears the TPM when that happens. This can only happen when the
* TPM is unowned, so it is OK to clear it (and we really have no choice).
* This is not expected to happen frequently, but it could happen.
*/
uint32_t safe_write(uint32_t index, const void *data, uint32_t length);
/**
* Similarly to safe_write(), this ensures we don't fail a DefineSpace because
* we hit the TPM write limit. This is even less likely to happen than with
* writes because we only define spaces once at initialization, but we'd rather
* be paranoid about this.
*/
uint32_t safe_define_space(uint32_t index, uint32_t perm, uint32_t size);
/**
* Perform one-time initializations.
*
* Create the NVRAM spaces, and set their initial values as needed. Sets the
* nvLocked bit and ensures the physical presence command is enabled and
* locked.
*/
uint32_t factory_initialize_tpm(struct vb2_context *ctx);
/**
* Start the TPM and establish the root of trust for the antirollback mechanism.
*/
uint32_t setup_tpm(struct vb2_context *ctx);
#endif /* ANTIROLLBACK_H_ */
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