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