| /* Copyright (c) 2011 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 updating the TPM state with the status of boot path. |
| */ |
| |
| #include "tpm_bootmode.h" |
| |
| #include "tlcl.h" |
| #include "utility.h" |
| #include "vboot_api.h" |
| |
| /* TPM PCR to use for storing boot mode measurements. */ |
| #define BOOT_MODE_PCR 0 |
| |
| /* Input digests for PCR extend. |
| * These are calculated as: |
| * SHA1("|Developer_Mode||Recovery_Mode||Keyblock_Mode|"). |
| * Developer_Mode can be 0 or 1. |
| * Recovery_Mode can be 0 or 1. |
| * Keyblock flags are defined in vboot_struct.h |
| * |
| * We map them to Keyblock_Mode as follows: |
| * ----------------------------------------- |
| * Keyblock Flags | Keyblock Mode |
| * ----------------------------------------- |
| * 6 (Dev-signed firmware) | 2 |
| * 7 Normal-signed firmware | 1 |
| * (anything else) | 0 |
| */ |
| |
| const char* kBootStateSHA1Digests[] = { |
| /* SHA1("\x00\x00\x00") */ |
| "\x29\xe2\xdc\xfb\xb1\x6f\x63\xbb\x02\x54\xdf\x75\x85\xa1\x5b\xb6" |
| "\xfb\x5e\x92\x7d", |
| |
| /* SHA1("\x00\x00\x01") */ |
| "\x25\x47\xcc\x73\x6e\x95\x1f\xa4\x91\x98\x53\xc4\x3a\xe8\x90\x86" |
| "\x1a\x3b\x32\x64", |
| |
| /* SHA1("\x00\x00\x02") */ |
| "\x1e\xf6\x24\x48\x2d\x62\x0e\x43\xe6\xd3\x4d\xa1\xaf\xe4\x62\x67" |
| "\xfc\x69\x5d\x9b", |
| |
| /* SHA1("\x00\x01\x00") */ |
| "\x62\x57\x18\x91\x21\x5b\x4e\xfc\x1c\xea\xb7\x44\xce\x59\xdd\x0b" |
| "\x66\xea\x6f\x73", |
| |
| /* SHA1("\x00\x01\x01") */ |
| "\xee\xe4\x47\xed\xc7\x9f\xea\x1c\xa7\xc7\xd3\x4e\x46\x32\x61\xcd" |
| "\xa4\xba\x33\x9e", |
| |
| /* SHA1("\x00\x01\x02") */ |
| "\x0c\x7a\x62\x3f\xd2\xbb\xc0\x5b\x06\x42\x3b\xe3\x59\xe4\x02\x1d" |
| "\x36\xe7\x21\xad", |
| |
| /* SHA1("\x01\x00\x00") */ |
| "\x95\x08\xe9\x05\x48\xb0\x44\x0a\x4a\x61\xe5\x74\x3b\x76\xc1\xe3" |
| "\x09\xb2\x3b\x7f", |
| |
| /* SHA1("\x01\x00\x01") */ |
| "\xc4\x2a\xc1\xc4\x6f\x1d\x4e\x21\x1c\x73\x5c\xc7\xdf\xad\x4f\xf8" |
| "\x39\x11\x10\xe9", |
| |
| /* SHA1("\x01\x00\x02") */ |
| "\xfa\x01\x0d\x26\x64\xcc\x5b\x3b\x82\xee\x48\x8f\xe2\xb9\xf5\x0f" |
| "\x49\x32\xeb\x8f", |
| |
| /* SHA1("\x01\x01\x00") */ |
| "\x47\xec\x8d\x98\x36\x64\x33\xdc\x00\x2e\x77\x21\xc9\xe3\x7d\x50" |
| "\x67\x54\x79\x37", |
| |
| /* SHA1("\x01\x01\x01") */ |
| "\x28\xd8\x6c\x56\xb3\xbf\x26\xd2\x36\x56\x9b\x8d\xc8\xc3\xf9\x1f" |
| "\x32\xf4\x7b\xc7", |
| |
| /* SHA1("\x01\x01\x02") */ |
| "\x12\xa3\x40\xd7\x89\x7f\xe7\x13\xfc\x8f\x02\xac\x53\x65\xb8\x6e" |
| "\xbf\x35\x31\x78", |
| }; |
| |
| #define MAX_BOOT_STATE_INDEX (sizeof(kBootStateSHA1Digests)/sizeof(char*)) |
| |
| /* Used for PCR extend when the passed-in boot state is invalid or |
| * if there is an internal error. */ |
| const uint8_t kBootInvalidSHA1Digest[] = { |
| "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" |
| "\xff\xff\xff\xff" |
| }; |
| |
| /* Given the boot state, return the correct SHA1 digest index for TPMExtend |
| * in kBootStateSHA1Digests[]. */ |
| int GetBootStateIndex(int dev_mode, int rec_mode, uint64_t keyblock_flags) { |
| int index = 0; |
| |
| /* Convert keyblock flags into keyblock mode which we use to index into |
| * kBootStateSHA1Digest[]. */ |
| switch(keyblock_flags) { |
| case 6: /* KEY_BLOCK_FLAG_RECOVERY_0 | KEY_BLOCK_FLAG_DEVELOPER_1 */ |
| /* Developer firmware. */ |
| index = 2; |
| break; |
| case 7: /* KEY_BLOCK_FLAG_RECOVERY_0 | KEY_BLOCK_FLAG_DEVELOPER_0 |
| * | KEY_BLOCK_FLAGS_DEVELOPER_1 */ |
| index = 1; |
| break; |
| default: |
| index = 0; /* Any other keyblock flags. */ |
| }; |
| |
| if (rec_mode) |
| index += 3; |
| if (dev_mode) |
| index += 6; |
| return index; |
| } |
| |
| uint32_t SetTPMBootModeState(int developer_mode, int recovery_mode, |
| uint64_t fw_keyblock_flags) { |
| uint32_t result; |
| const uint8_t* in_digest = NULL; |
| uint8_t out_digest[20]; /* For PCR extend output. */ |
| int digest_index = GetBootStateIndex(developer_mode, recovery_mode, |
| fw_keyblock_flags); |
| |
| if (digest_index >= 0 && digest_index < MAX_BOOT_STATE_INDEX) |
| in_digest = (const uint8_t*)kBootStateSHA1Digests[digest_index]; |
| else |
| in_digest = kBootInvalidSHA1Digest; /* Internal out of bounds error. */ |
| result = TlclExtend(BOOT_MODE_PCR, in_digest, out_digest); |
| VBDEBUG(("TPM: SetTPMBootModeState boot mode PCR out_digest %02x %02x %02x " |
| "%02x\n", out_digest, out_digest+1, out_digest+2, out_digest+3)); |
| return result; |
| } |