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security/tpm: Unify the coreboot TPM software stack

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* Remove 2nd software stack in pc80 drivers directory.
* Create TSPI interface for common usage.
* Refactor TSS / TIS code base.
* Add vendor tss (Cr50) directory.
* Change kconfig options for TPM to TPM1.
* Add user / board configuration with:
  * MAINBOARD_HAS_*_TPM # * BUS driver
  * MAINBOARD_HAS_TPM1 or MAINBOARD_HAS_TPM2
  * Add kconfig TPM user selection (e.g. pluggable TPMs)
* Fix existing headers and function calls.
* Fix vboot for interface usage and antirollback mode.

Change-Id: I7ec277e82a3c20c62a0548a1a2b013e6ce8f5b3f
Signed-off-by: Philipp Deppenwiese <zaolin@das-labor.org>
Reviewed-on: https://review.coreboot.org/24903
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Philipp Deppenwiese 2018-02-27 19:40:52 +01:00 • committed by Martin Roth
commit c07f8fbe6f
112 changed files with 1132 additions and 1402 deletions
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5
src/security/vboot/Kconfig
View file

@ -17,10 +17,7 @@ menu "Verified Boot (vboot)"
config VBOOT
bool "Verify firmware with vboot."
default n
select TPM if !MAINBOARD_HAS_TPM2 && !VBOOT_MOCK_SECDATA
select TPM2 if MAINBOARD_HAS_TPM2 && !VBOOT_MOCK_SECDATA
select TPM_INIT_FAILURE_IS_FATAL if PC80_SYSTEM && LPC_TPM
select SKIP_TPM_STARTUP_ON_NORMAL_BOOT if PC80_SYSTEM && LPC_TPM
select VBOOT_MOCK_SECDATA if !TPM1 && !TPM2
depends on HAVE_HARD_RESET
help
Enabling VBOOT will use vboot to verify the components of the firmware

66
src/security/vboot/antirollback.h Normal file
View file

@ -0,0 +1,66 @@
/* 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 ANTIROLLBACK_H_
#define ANTIROLLBACK_H_
#include <types.h>
#include <security/tpm/tspi.h>
struct vb2_context;
enum vb2_pcr_digest;
/* TPM NVRAM location indices. */
#define FIRMWARE_NV_INDEX 0x1007
#define KERNEL_NV_INDEX 0x1008
/* 0x1009 used to be used as a backup space. Think of conflicts if you
* want to use 0x1009 for something else. */
#define BACKUP_NV_INDEX 0x1009
#define FWMP_NV_INDEX 0x100a
#define REC_HASH_NV_INDEX 0x100b
#define REC_HASH_NV_SIZE VB2_SHA256_DIGEST_SIZE
/* Structure definitions for TPM spaces */
/* 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
/* All functions return TPM_SUCCESS (zero) if successful, non-zero if error */
uint32_t antirollback_read_space_firmware(struct vb2_context *ctx);
/**
* Write may be called if the versions change.
*/
uint32_t antirollback_write_space_firmware(struct vb2_context *ctx);
/**
* Lock must be called.
*/
uint32_t antirollback_lock_space_firmware(void);
/* Read recovery hash data from TPM. */
uint32_t antirollback_read_space_rec_hash(uint8_t *data, uint32_t size);
/* Write new hash data to recovery space in TPM. */
uint32_t antirollback_write_space_rec_hash(const uint8_t *data, uint32_t size);
/* Lock down recovery hash space in TPM. */
uint32_t antirollback_lock_space_rec_hash(void);
/* Start of the root of trust */
uint32_t vboot_setup_tpm(struct vb2_context *ctx);
/* vboot_extend_pcr function for vb2 context */
uint32_t vboot_extend_pcr(struct vb2_context *ctx, int pcr,
enum vb2_pcr_digest which_digest);
#endif /* ANTIROLLBACK_H_ */

30
src/security/vboot/secdata_mock.c
View file

@ -32,54 +32,50 @@
* stored in the TPM NVRAM.
*/
#include <security/tpm/antirollback.h>
#include <stdlib.h>
#include <security/tpm/tss.h>
#include <security/tpm/tspi.h>
#include <vb2_api.h>
uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
enum vb2_pcr_digest which_digest)
#include "antirollback.h"
int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t tpm_clear_and_reenable(void)
uint32_t vboot_extend_pcr(struct vb2_context *ctx, int pcr,
enum vb2_pcr_digest which_digest)
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_read_space_firmware(struct vb2_context *ctx)
{
vb2api_secdata_create(ctx);
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_write_space_firmware(struct vb2_context *ctx)
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_lock_space_firmware()
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_lock_space_rec_hash(void)
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_read_space_rec_hash(uint8_t *data, uint32_t size)
{
return TPM_SUCCESS;
return VB2_SUCCESS;
}
uint32_t antirollback_write_space_rec_hash(const uint8_t *data, uint32_t size)
{
return TPM_SUCCESS;
}
uint32_t tlcl_lib_init(void)
{
return VB2_SUCCESS;
}

179
src/security/vboot/secdata_tpm.c
View file

@ -32,10 +32,10 @@
* stored in the TPM NVRAM.
*/
#include <security/tpm/antirollback.h>
#include <security/vboot/antirollback.h>
#include <stdlib.h>
#include <string.h>
#include <security/tpm/tss.h>
#include <security/tpm/tspi.h>
#include <vb2_api.h>
#include <console/console.h>
@ -64,7 +64,7 @@
static uint32_t safe_write(uint32_t index, const void *data, uint32_t length);
uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
uint32_t vboot_extend_pcr(struct vb2_context *ctx, int pcr,
enum vb2_pcr_digest which_digest)
{
uint8_t buffer[VB2_PCR_DIGEST_RECOMMENDED_SIZE];
@ -74,10 +74,10 @@ uint32_t tpm_extend_pcr(struct vb2_context *ctx, int pcr,
rv = vb2api_get_pcr_digest(ctx, which_digest, buffer, &size);
if (rv != VB2_SUCCESS)
return rv;
if (size < TPM_PCR_DIGEST)
if (size < TPM_PCR_MINIMUM_DIGEST_SIZE)
return VB2_ERROR_UNKNOWN;
return tlcl_extend(pcr, buffer, NULL);
return tpm_extend_pcr(pcr, buffer, NULL);
}
static uint32_t read_space_firmware(struct vb2_context *ctx)
@ -158,6 +158,35 @@ static const uint8_t secdata_kernel[] = {
static const uint8_t rec_hash_data[REC_HASH_NV_SIZE] = { };
#if IS_ENABLED(CONFIG_TPM2)
/*
* Different sets of NVRAM space attributes apply to the "ro" spaces,
* i.e. those which should not be possible to delete or modify once
* the RO exits, and the rest of the NVRAM spaces.
*/
const static TPMA_NV ro_space_attributes = {
.TPMA_NV_PPWRITE = 1,
.TPMA_NV_AUTHREAD = 1,
.TPMA_NV_PPREAD = 1,
.TPMA_NV_PLATFORMCREATE = 1,
.TPMA_NV_WRITE_STCLEAR = 1,
.TPMA_NV_POLICY_DELETE = 1,
};
const static TPMA_NV rw_space_attributes = {
.TPMA_NV_PPWRITE = 1,
.TPMA_NV_AUTHREAD = 1,
.TPMA_NV_PPREAD = 1,
.TPMA_NV_PLATFORMCREATE = 1,
};
/*
* This policy digest was obtained using TPM2_PolicyPCR
* selecting only PCR_0 with a value of all zeros.
*/
const static uint8_t pcr0_unchanged_policy[] = {
0x09, 0x93, 0x3C, 0xCE, 0xEB, 0xB4, 0x41, 0x11, 0x18, 0x81, 0x1D,
0xD4, 0x47, 0x78, 0x80, 0x08, 0x88, 0x86, 0x62, 0x2D, 0xD7, 0x79,
0x94, 0x46, 0x62, 0x26, 0x68, 0x8E, 0xEE, 0xE6, 0x6A, 0xA1};
/* Nothing special in the TPM2 path yet. */
static uint32_t safe_write(uint32_t index, const void *data, uint32_t length)
@ -166,11 +195,13 @@ static uint32_t safe_write(uint32_t index, const void *data, uint32_t length)
}
static uint32_t set_space(const char *name, uint32_t index, const void *data,
uint32_t length)
uint32_t length, const TPMA_NV nv_attributes,
const uint8_t *nv_policy, size_t nv_policy_size)
{
uint32_t rv;
rv = tlcl_define_space(index, length);
rv = tlcl_define_space(index, length, nv_attributes, nv_policy,
nv_policy_size);
if (rv == TPM_E_NV_DEFINED) {
/*
* Continue with writing: it may be defined, but not written
@ -193,19 +224,22 @@ static uint32_t set_space(const char *name, uint32_t index, const void *data,
static uint32_t set_firmware_space(const void *firmware_blob)
{
return set_space("firmware", FIRMWARE_NV_INDEX, firmware_blob,
VB2_SECDATA_SIZE);
VB2_SECDATA_SIZE, ro_space_attributes,
pcr0_unchanged_policy, sizeof(pcr0_unchanged_policy));
}
static uint32_t set_kernel_space(const void *kernel_blob)
{
return set_space("kernel", KERNEL_NV_INDEX, kernel_blob,
sizeof(secdata_kernel));
sizeof(secdata_kernel), rw_space_attributes, NULL, 0);
}
static uint32_t set_rec_hash_space(const uint8_t *data)
{
return set_space("MRC Hash", REC_HASH_NV_INDEX, data,
REC_HASH_NV_SIZE);
REC_HASH_NV_SIZE,
ro_space_attributes, pcr0_unchanged_policy,
sizeof(pcr0_unchanged_policy));
}
static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
@ -228,13 +262,6 @@ static uint32_t _factory_initialize_tpm(struct vb2_context *ctx)
return TPM_SUCCESS;
}
uint32_t tpm_clear_and_reenable(void)
{
VBDEBUG("TPM: Clear and re-enable\n");
RETURN_ON_FAILURE(tlcl_force_clear());
return TPM_SUCCESS;
}
uint32_t antirollback_lock_space_firmware(void)
{
return tlcl_lock_nv_write(FIRMWARE_NV_INDEX);
@ -247,16 +274,6 @@ uint32_t antirollback_lock_space_rec_hash(void)
#else
uint32_t tpm_clear_and_reenable(void)
{
VBDEBUG("TPM: Clear and re-enable\n");
RETURN_ON_FAILURE(tlcl_force_clear());
RETURN_ON_FAILURE(tlcl_set_enable());
RETURN_ON_FAILURE(tlcl_set_deactivated(0));
return TPM_SUCCESS;
}
/**
* Like tlcl_write(), 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
@ -416,110 +433,22 @@ static uint32_t factory_initialize_tpm(struct vb2_context *ctx)
return TPM_SUCCESS;
}
/*
* SetupTPM starts the TPM and establishes the root of trust for the
* anti-rollback mechanism. SetupTPM can fail for three reasons. 1 A bug. 2 a
* TPM hardware failure. 3 An unexpected TPM state due to some attack. In
* general we cannot easily distinguish the kind of failure, so our strategy is
* to reboot in recovery mode in all cases. The recovery mode calls SetupTPM
* again, which executes (almost) the same sequence of operations. There is a
* good chance that, if recovery mode was entered because of a TPM failure, the
* failure will repeat itself. (In general this is impossible to guarantee
* because we have no way of creating the exact TPM initial state at the
* previous boot.) In recovery mode, we ignore the failure and continue, thus
* giving the recovery kernel a chance to fix things (that's why we don't set
* bGlobalLock). The choice is between a knowingly insecure device and a
* bricked device.
*
* As a side note, observe that we go through considerable hoops to avoid using
* the STCLEAR permissions for the index spaces. We do this to avoid writing
* to the TPM flashram at every reboot or wake-up, because of concerns about
* the durability of the NVRAM.
*/
uint32_t setup_tpm(struct vb2_context *ctx)
uint32_t vboot_setup_tpm(struct vb2_context *ctx)
{
uint8_t disable;
uint8_t deactivated;
uint32_t result;
RETURN_ON_FAILURE(tlcl_lib_init());
/* Handle special init for S3 resume path */
if (ctx->flags & VB2_CONTEXT_S3_RESUME) {
result = tlcl_resume();
if (result == TPM_E_INVALID_POSTINIT)
printk(BIOS_DEBUG, "TPM: Already initialized.\n");
return TPM_SUCCESS;
}
if (IS_ENABLED(CONFIG_VBOOT_SOFT_REBOOT_WORKAROUND)) {
result = tlcl_startup();
if (result == TPM_E_INVALID_POSTINIT) {
/*
* Some prototype hardware doesn't reset the TPM on a CPU
* reset. We do a hard reset to get around this.
*/
VBDEBUG("TPM: soft reset detected\n");
ctx->flags |= VB2_CONTEXT_SECDATA_WANTS_REBOOT;
return TPM_E_MUST_REBOOT;
} else if (result != TPM_SUCCESS) {
VBDEBUG("TPM: tlcl_startup returned %08x\n", result);
return result;
}
} else
RETURN_ON_FAILURE(tlcl_startup());
/*
* Some TPMs start the self test automatically at power on. In that case
* we don't need to call ContinueSelfTest. On some (other) TPMs,
* continue_self_test may block. In that case, we definitely don't want
* to call it here. For TPMs in the intersection of these two sets, we
* are screwed. (In other words: TPMs that require manually starting the
* self-test AND block will have poor performance until we split
* tlcl_send_receive() into send() and receive(), and have a state
* machine to control setup.)
*
* This comment is likely to become obsolete in the near future, so
* don't trust it. It may have not been updated.
*/
#ifdef TPM_MANUAL_SELFTEST
#ifdef TPM_BLOCKING_CONTINUESELFTEST
#warning "lousy TPM!"
#endif
RETURN_ON_FAILURE(tlcl_continue_self_test());
#endif
result = tlcl_assert_physical_presence();
if (result != TPM_SUCCESS) {
/*
* It is possible that the TPM was delivered with the physical
* presence command disabled. This tries enabling it, then
* tries asserting PP again.
*/
RETURN_ON_FAILURE(tlcl_physical_presence_cmd_enable());
RETURN_ON_FAILURE(tlcl_assert_physical_presence());
}
/* Check that the TPM is enabled and activated. */
RETURN_ON_FAILURE(tlcl_get_flags(&disable, &deactivated, NULL));
if (disable || deactivated) {
VBDEBUG("TPM: disabled (%d) or deactivated (%d). Fixing...\n",
disable, deactivated);
RETURN_ON_FAILURE(tlcl_set_enable());
RETURN_ON_FAILURE(tlcl_set_deactivated(0));
VBDEBUG("TPM: Must reboot to re-enable\n");
result = tpm_setup(ctx->flags & VB2_CONTEXT_S3_RESUME);
if (result == TPM_E_MUST_REBOOT)
ctx->flags |= VB2_CONTEXT_SECDATA_WANTS_REBOOT;
return TPM_E_MUST_REBOOT;
}
VBDEBUG("TPM: SetupTPM() succeeded\n");
return TPM_SUCCESS;
return result;
}
uint32_t antirollback_read_space_firmware(struct vb2_context *ctx)
{
uint32_t rv;
rv = setup_tpm(ctx);
rv = vboot_setup_tpm(ctx);
if (rv)
return rv;
@ -585,3 +514,13 @@ uint32_t antirollback_write_space_rec_hash(const uint8_t *data, uint32_t size)
return write_secdata(REC_HASH_NV_INDEX, data, size);
}
int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
{
uint32_t rv;
printk(BIOS_INFO, "Clearing TPM owner\n");
rv = tpm_clear_and_reenable();
if (rv)
return VB2_ERROR_EX_TPM_CLEAR_OWNER;
return VB2_SUCCESS;
}

17
src/security/vboot/vboot_logic.c
View file

@ -13,7 +13,6 @@
* GNU General Public License for more details.
*/
#include <security/tpm/antirollback.h>
#include <arch/exception.h>
#include <assert.h>
#include <bootmode.h>
@ -27,6 +26,8 @@
#include <security/vboot/misc.h>
#include <security/vboot/vbnv.h>
#include "antirollback.h"
/* The max hash size to expect is for SHA512. */
#define VBOOT_MAX_HASH_SIZE VB2_SHA512_DIGEST_SIZE
@ -53,16 +54,6 @@ void vb2ex_printf(const char *func, const char *fmt, ...)
return;
}
int vb2ex_tpm_clear_owner(struct vb2_context *ctx)
{
uint32_t rv;
printk(BIOS_INFO, "Clearing TPM owner\n");
rv = tpm_clear_and_reenable();
if (rv)
return VB2_ERROR_EX_TPM_CLEAR_OWNER;
return VB2_SUCCESS;
}
int vb2ex_read_resource(struct vb2_context *ctx,
enum vb2_resource_index index,
uint32_t offset,
@ -290,8 +281,8 @@ static void save_if_needed(struct vb2_context *ctx)
static uint32_t extend_pcrs(struct vb2_context *ctx)
{
return tpm_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
tpm_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
return vboot_extend_pcr(ctx, 0, BOOT_MODE_PCR) ||
vboot_extend_pcr(ctx, 1, HWID_DIGEST_PCR);
}
/**