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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 VBOOT_REFERENCE_ROLLBACK_INDEX_H_
#define VBOOT_REFERENCE_ROLLBACK_INDEX_H_
#include "sysincludes.h"
#include "tss_constants.h"
/* 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
#define BACKUP_NV_SIZE 16
/* Structure definitions for TPM spaces */
/* Kernel space - KERNEL_NV_INDEX, locked with physical presence. */
#define ROLLBACK_SPACE_KERNEL_VERSION 2
#define ROLLBACK_SPACE_KERNEL_UID 0x4752574C /* 'GRWL' */
typedef struct RollbackSpaceKernel {
/* Struct version, for backwards compatibility */
uint8_t struct_version;
/* Unique ID to detect space redefinition */
uint32_t uid;
/* Kernel versions */
uint32_t kernel_versions;
/* Reserved for future expansion */
uint8_t reserved[3];
/* Checksum (v2 and later only) */
uint8_t crc8;
} __attribute__((packed)) RollbackSpaceKernel;
/* 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
/*
* Some systems may not have a dedicated dev-mode switch, but enter and leave
* dev-mode through some recovery-mode magic keypresses. For those systems, the
* dev-mode "switch" state is in this bit (0=normal, 1=dev). To make it work, a
* new flag is passed to VbInit(), indicating that the system lacks a physical
* dev-mode switch. If a physical switch is present, this bit is ignored.
*/
#define FLAG_VIRTUAL_DEV_MODE_ON 0x02
/* Firmware space - FIRMWARE_NV_INDEX, locked with global lock. */
#define ROLLBACK_SPACE_FIRMWARE_VERSION 2
typedef struct RollbackSpaceFirmware {
/* Struct version, for backwards compatibility */
uint8_t struct_version;
/* Flags (see FLAG_* above) */
uint8_t flags;
/* Firmware versions */
uint32_t fw_versions;
/* Reserved for future expansion */
uint8_t reserved[3];
/* Checksum (v2 and later only) */
uint8_t crc8;
} __attribute__((packed)) RollbackSpaceFirmware;
/* All functions return TPM_SUCCESS (zero) if successful, non-zero if error */
/*
* These functions are called from VbInit(). They cannot use global
* variables.
*/
uint32_t RollbackS3Resume(void);
/*
* These functions are callable from VbSelectFirmware(). They cannot use
* global variables.
*/
/**
* This must be called.
*/
uint32_t RollbackFirmwareSetup(int is_hw_dev,
int disable_dev_request,
int clear_tpm_owner_request,
/* two outputs on success */
int *is_virt_dev, uint32_t *tpm_version);
/**
* Write may be called if the versions change.
*/
uint32_t RollbackFirmwareWrite(uint32_t version);
/**
* Lock must be called.
*/
uint32_t RollbackFirmwareLock(void);
/*
* These functions are callable from VbSelectAndLoadKernel(). They may use
* global variables.
*/
/**
* Read stored kernel version.
*/
uint32_t RollbackKernelRead(uint32_t *version);
/**
* Write stored kernel version.
*/
uint32_t RollbackKernelWrite(uint32_t version);
/**
* Read backup data.
*/
uint32_t RollbackBackupRead(uint8_t *raw);
/**
* Write backup data.
*/
uint32_t RollbackBackupWrite(uint8_t *raw);
/**
* Lock must be called. Internally, it's ignored in recovery mode.
*/
uint32_t RollbackKernelLock(int recovery_mode);
/****************************************************************************/
/*
* 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 TPMClearAndReenable(void);
/**
* Like TlclWrite(), 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 SafeWrite(uint32_t index, const void *data, uint32_t length);
/**
* Similarly to SafeWrite(), 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 SafeDefineSpace(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 OneTimeInitializeTPM(RollbackSpaceFirmware *rsf,
RollbackSpaceKernel *rsk);
/**
* Start the TPM and establish the root of trust for the anti-rollback
* mechanism.
*/
uint32_t SetupTPM(int developer_mode, int disable_dev_request,
int clear_tpm_owner_request, RollbackSpaceFirmware *rsf);
/**
* Utility function to turn the virtual dev-mode flag on or off. 0=off, 1=on.
*/
uint32_t SetVirtualDevMode(int val);
#endif /* VBOOT_REFERENCE_ROLLBACK_INDEX_H_ */
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