93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
/* Copyright (c) 2014 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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/* Non-volatile storage routines.
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*/
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#include "sysincludes.h"
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#include "crc8.h"
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#include "utility.h"
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#include "vboot_common.h"
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#include "vboot_nvstorage.h"
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#include "rollback_index.h"
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/* These are the fields of the nvram that we want to back up. */
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static const VbNvParam backup_params[] = {
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VBNV_KERNEL_FIELD,
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VBNV_LOCALIZATION_INDEX,
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VBNV_DEV_BOOT_USB,
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VBNV_DEV_BOOT_LEGACY,
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VBNV_DEV_BOOT_SIGNED_ONLY,
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};
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/* We can't back things up if there isn't enough storage. */
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BUILD_ASSERT(VBNV_BLOCK_SIZE <= BACKUP_NV_SIZE);
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int RestoreNvFromBackup(VbNvContext *vnc)
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{
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VbNvContext bvnc;
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uint32_t value;
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int i;
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VBDEBUG(("TPM: %s()\n", __func__));
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if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
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return 1;
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VbNvSetup(&bvnc);
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if (bvnc.regenerate_crc) {
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VBDEBUG(("TPM: Oops, backup is no good.\n"));
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return 1;
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}
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for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
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VbNvGet(&bvnc, backup_params[i], &value);
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VbNvSet(vnc, backup_params[i], value);
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}
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/* VbNvTeardown(&bvnc); is not needed. We're done with it. */
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return 0;
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}
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int SaveNvToBackup(VbNvContext *vnc)
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{
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VbNvContext bvnc;
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uint32_t value;
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int i;
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VBDEBUG(("TPM: %s()\n", __func__));
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/* Read it first. No point in writing the same data. */
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if (TPM_SUCCESS != RollbackBackupRead(bvnc.raw))
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return 1;
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VbNvSetup(&bvnc);
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VBDEBUG(("TPM: existing backup is %s\n",
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bvnc.regenerate_crc ? "bad" : "good"));
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for (i = 0; i < ARRAY_SIZE(backup_params); i++) {
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VbNvGet(vnc, backup_params[i], &value);
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VbNvSet(&bvnc, backup_params[i], value);
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}
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VbNvTeardown(&bvnc);
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if (!bvnc.raw_changed) {
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VBDEBUG(("TPM: Nothing's changed, not writing backup\n"));
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/* Clear the request flag, since we're happy. */
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VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
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return 0;
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}
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if (TPM_SUCCESS == RollbackBackupWrite(bvnc.raw)) {
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/* Clear the request flag if we wrote successfully too */
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VbNvSet(vnc, VBNV_BACKUP_NVRAM_REQUEST, 0);
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return 0;
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}
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VBDEBUG(("TPM: Sorry, couldn't write backup.\n"));
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return 1;
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}
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