Philipp Deppenwiese | c07f8fb | 2018-02-27 19:40:52 +0100 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright (c) 2013 The Chromium OS Authors. All rights reserved. |
| 5 | * Copyright 2017 Facebook Inc. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; version 2 of the License. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | */ |
| 16 | |
| 17 | #include <console/cbmem_console.h> |
| 18 | #include <console/console.h> |
| 19 | #include <reset.h> |
| 20 | #include <security/tpm/tspi.h> |
| 21 | #include <security/tpm/tss.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <string.h> |
| 24 | |
| 25 | #if IS_ENABLED(CONFIG_TPM1) |
| 26 | static uint32_t tpm1_invoke_state_machine(void) |
| 27 | { |
| 28 | uint8_t disable; |
| 29 | uint8_t deactivated; |
| 30 | uint32_t result = TPM_SUCCESS; |
| 31 | |
| 32 | /* Check that the TPM is enabled and activated. */ |
| 33 | result = tlcl_get_flags(&disable, &deactivated, NULL); |
| 34 | if (result != TPM_SUCCESS) { |
| 35 | printk(BIOS_ERR, "TPM: Can't read capabilities.\n"); |
| 36 | return result; |
| 37 | } |
| 38 | |
| 39 | if (!!deactivated != IS_ENABLED(CONFIG_TPM_DEACTIVATE)) { |
| 40 | printk(BIOS_INFO, |
| 41 | "TPM: Unexpected TPM deactivated state. Toggling...\n"); |
| 42 | result = tlcl_set_deactivated(!deactivated); |
| 43 | if (result != TPM_SUCCESS) { |
| 44 | printk(BIOS_ERR, |
| 45 | "TPM: Can't toggle deactivated state.\n"); |
| 46 | return result; |
| 47 | } |
| 48 | |
| 49 | deactivated = !deactivated; |
| 50 | result = TPM_E_MUST_REBOOT; |
| 51 | } |
| 52 | |
| 53 | if (disable && !deactivated) { |
| 54 | printk(BIOS_INFO, "TPM: disabled (%d). Enabling...\n", disable); |
| 55 | |
| 56 | result = tlcl_set_enable(); |
| 57 | if (result != TPM_SUCCESS) { |
| 58 | printk(BIOS_ERR, "TPM: Can't set enabled state.\n"); |
| 59 | return result; |
| 60 | } |
| 61 | |
| 62 | printk(BIOS_INFO, "TPM: Must reboot to re-enable\n"); |
| 63 | result = TPM_E_MUST_REBOOT; |
| 64 | } |
| 65 | |
| 66 | return result; |
| 67 | } |
| 68 | #endif |
| 69 | |
| 70 | /* |
| 71 | * tpm_setup starts the TPM and establishes the root of trust for the |
| 72 | * anti-rollback mechanism. SetupTPM can fail for three reasons. 1 A bug. 2 a |
| 73 | * TPM hardware failure. 3 An unexpected TPM state due to some attack. In |
| 74 | * general we cannot easily distinguish the kind of failure, so our strategy is |
| 75 | * to reboot in recovery mode in all cases. The recovery mode calls SetupTPM |
| 76 | * again, which executes (almost) the same sequence of operations. There is a |
| 77 | * good chance that, if recovery mode was entered because of a TPM failure, the |
| 78 | * failure will repeat itself. (In general this is impossible to guarantee |
| 79 | * because we have no way of creating the exact TPM initial state at the |
| 80 | * previous boot.) In recovery mode, we ignore the failure and continue, thus |
| 81 | * giving the recovery kernel a chance to fix things (that's why we don't set |
| 82 | * bGlobalLock). The choice is between a knowingly insecure device and a |
| 83 | * bricked device. |
| 84 | * |
| 85 | * As a side note, observe that we go through considerable hoops to avoid using |
| 86 | * the STCLEAR permissions for the index spaces. We do this to avoid writing |
| 87 | * to the TPM flashram at every reboot or wake-up, because of concerns about |
| 88 | * the durability of the NVRAM. |
| 89 | */ |
| 90 | uint32_t tpm_setup(int s3flag) |
| 91 | { |
| 92 | uint32_t result; |
| 93 | |
| 94 | result = tlcl_lib_init(); |
| 95 | if (result != TPM_SUCCESS) { |
| 96 | printk(BIOS_ERR, "TPM: Can't initialize.\n"); |
| 97 | goto out; |
| 98 | } |
| 99 | |
| 100 | /* Handle special init for S3 resume path */ |
| 101 | if (s3flag) { |
| 102 | result = tlcl_resume(); |
| 103 | if (result == TPM_E_INVALID_POSTINIT) |
| 104 | printk(BIOS_INFO, "TPM: Already initialized.\n"); |
| 105 | |
| 106 | return TPM_SUCCESS; |
| 107 | } |
| 108 | |
| 109 | result = tlcl_startup(); |
| 110 | if (result != TPM_SUCCESS) { |
| 111 | printk(BIOS_ERR, "TPM: Can't run startup command.\n"); |
| 112 | goto out; |
| 113 | } |
| 114 | |
| 115 | result = tlcl_assert_physical_presence(); |
| 116 | if (result != TPM_SUCCESS) { |
| 117 | /* |
| 118 | * It is possible that the TPM was delivered with the physical |
| 119 | * presence command disabled. This tries enabling it, then |
| 120 | * tries asserting PP again. |
| 121 | */ |
| 122 | result = tlcl_physical_presence_cmd_enable(); |
| 123 | if (result != TPM_SUCCESS) { |
| 124 | printk( |
| 125 | BIOS_ERR, |
| 126 | "TPM: Can't enable physical presence command.\n"); |
| 127 | goto out; |
| 128 | } |
| 129 | |
| 130 | result = tlcl_assert_physical_presence(); |
| 131 | if (result != TPM_SUCCESS) { |
| 132 | printk(BIOS_ERR, |
| 133 | "TPM: Can't assert physical presence.\n"); |
| 134 | goto out; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | #if IS_ENABLED(CONFIG_TPM1) |
| 139 | result = tpm1_invoke_state_machine(); |
| 140 | if (result != TPM_SUCCESS) |
| 141 | return result; |
| 142 | #endif |
| 143 | |
| 144 | out: |
| 145 | if (result != TPM_SUCCESS) |
| 146 | post_code(POST_TPM_FAILURE); |
| 147 | else |
| 148 | printk(BIOS_INFO, "TPM: setup succeeded\n"); |
| 149 | |
| 150 | return result; |
| 151 | } |
| 152 | |
| 153 | uint32_t tpm_clear_and_reenable(void) |
| 154 | { |
| 155 | uint32_t result; |
| 156 | |
| 157 | printk(BIOS_INFO, "TPM: Clear and re-enable\n"); |
| 158 | result = tlcl_force_clear(); |
| 159 | if (result != TPM_SUCCESS) { |
| 160 | printk(BIOS_ERR, "TPM: Can't initiate a force clear.\n"); |
| 161 | return result; |
| 162 | } |
| 163 | |
| 164 | #if IS_ENABLED(CONFIG_TPM1) |
| 165 | result = tlcl_set_enable(); |
| 166 | if (result != TPM_SUCCESS) { |
| 167 | printk(BIOS_ERR, "TPM: Can't set enabled state.\n"); |
| 168 | return result; |
| 169 | } |
| 170 | |
| 171 | result = tlcl_set_deactivated(0); |
| 172 | if (result != TPM_SUCCESS) { |
| 173 | printk(BIOS_ERR, "TPM: Can't set deactivated state.\n"); |
| 174 | return result; |
| 175 | } |
| 176 | #endif |
| 177 | |
| 178 | return TPM_SUCCESS; |
| 179 | } |
| 180 | |
Philipp Deppenwiese | f849972 | 2018-07-30 01:27:47 +0200 | [diff] [blame] | 181 | uint32_t tpm_extend_pcr(int pcr, uint8_t *digest, |
| 182 | size_t digest_len, const char *name) |
Philipp Deppenwiese | c07f8fb | 2018-02-27 19:40:52 +0100 | [diff] [blame] | 183 | { |
Philipp Deppenwiese | f849972 | 2018-07-30 01:27:47 +0200 | [diff] [blame] | 184 | uint32_t result; |
| 185 | |
Philipp Deppenwiese | c07f8fb | 2018-02-27 19:40:52 +0100 | [diff] [blame] | 186 | if (!digest) |
| 187 | return TPM_E_IOERROR; |
| 188 | |
Philipp Deppenwiese | f849972 | 2018-07-30 01:27:47 +0200 | [diff] [blame] | 189 | result = tlcl_extend(pcr, digest, NULL); |
| 190 | if (result != TPM_SUCCESS) |
| 191 | return result; |
Philipp Deppenwiese | c07f8fb | 2018-02-27 19:40:52 +0100 | [diff] [blame] | 192 | |
Philipp Deppenwiese | f849972 | 2018-07-30 01:27:47 +0200 | [diff] [blame] | 193 | result = tcpa_log_add_table_entry(name, pcr, digest, digest_len); |
| 194 | if (result != 0) |
| 195 | printk(BIOS_ERR, "ERROR: Couldn't create TCPA log entry\n"); |
| 196 | |
| 197 | return 0; |
Philipp Deppenwiese | c07f8fb | 2018-02-27 19:40:52 +0100 | [diff] [blame] | 198 | } |