96 lines
2.8 KiB
C
96 lines
2.8 KiB
C
/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* Functions for querying, manipulating and locking rollback indices
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* stored in the TPM NVRAM.
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*/
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#ifndef ANTIROLLBACK_H_
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#define ANTIROLLBACK_H_
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#include "tpm_lite/tss_constants.h"
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struct vb2_context;
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enum vb2_pcr_digest;
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/* TPM NVRAM location indices. */
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#define FIRMWARE_NV_INDEX 0x1007
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#define KERNEL_NV_INDEX 0x1008
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/* This is just an opaque space for backup purposes */
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#define BACKUP_NV_INDEX 0x1009
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/* Structure definitions for TPM spaces */
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/* Flags for firmware space */
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/*
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* Last boot was developer mode. TPM ownership is cleared when transitioning
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* to/from developer mode.
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*/
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#define FLAG_LAST_BOOT_DEVELOPER 0x01
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/* All functions return TPM_SUCCESS (zero) if successful, non-zero if error */
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uint32_t antirollback_read_space_firmware(struct vb2_context *ctx);
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/**
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* Write may be called if the versions change.
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*/
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uint32_t antirollback_write_space_firmware(struct vb2_context *ctx);
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/**
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* Lock must be called.
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*/
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uint32_t antirollback_lock_space_firmware(void);
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/****************************************************************************/
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/*
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* The following functions are internal apis, listed here for use by unit tests
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* only.
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*/
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/**
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* Ask vboot for a digest and extend a TPM PCR with it.
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*/
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uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
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enum vb2_pcr_digest which_digest);
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/**
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* Issue a TPM_Clear and reenable/reactivate the TPM.
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*/
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uint32_t tpm_clear_and_reenable(void);
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/**
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* Like tlcl_write(), but checks for write errors due to hitting the 64-write
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* limit and clears the TPM when that happens. This can only happen when the
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* TPM is unowned, so it is OK to clear it (and we really have no choice).
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* This is not expected to happen frequently, but it could happen.
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*/
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uint32_t safe_write(uint32_t index, const void *data, uint32_t length);
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/**
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* Similarly to safe_write(), this ensures we don't fail a DefineSpace because
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* we hit the TPM write limit. This is even less likely to happen than with
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* writes because we only define spaces once at initialization, but we'd rather
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* be paranoid about this.
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*/
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uint32_t safe_define_space(uint32_t index, uint32_t perm, uint32_t size);
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/**
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* Perform one-time initializations.
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*
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* Create the NVRAM spaces, and set their initial values as needed. Sets the
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* nvLocked bit and ensures the physical presence command is enabled and
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* locked.
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*/
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uint32_t factory_initialize_tpm(struct vb2_context *ctx);
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/**
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* Start the TPM and establish the root of trust for the antirollback mechanism.
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*/
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uint32_t setup_tpm(struct vb2_context *ctx);
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#endif /* ANTIROLLBACK_H_ */
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