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/* Copyright 2017 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.
*/
/*
* Verify and jump to a RW image if power supply is not sufficient.
*/
#include "battery.h"
#include "charge_manager.h"
#include "chipset.h"
#include "clock.h"
#include "console.h"
#include "flash.h"
#include "hooks.h"
#include "host_command.h"
#include "rsa.h"
#include "rwsig.h"
#include "stdbool.h"
#include "sha256.h"
#include "shared_mem.h"
#include "system.h"
#include "usb_pd.h"
#include "vboot.h"
#include "vb21_struct.h"
#define CPRINTS(format, args...) cprints(CC_VBOOT,"VB " format, ## args)
#define CPRINTF(format, args...) cprintf(CC_VBOOT,"VB " format, ## args)
static int has_matrix_keyboard(void)
{
return 0;
}
static int verify_slot(enum ec_image slot)
{
const struct vb21_packed_key *vb21_key;
const struct vb21_signature *vb21_sig;
const struct rsa_public_key *key;
const uint8_t *sig;
const uint8_t *data;
int len;
int rv;
CPRINTS("Verifying %s", ec_image_to_string(slot));
vb21_key = (const struct vb21_packed_key *)(
CONFIG_MAPPED_STORAGE_BASE +
CONFIG_EC_PROTECTED_STORAGE_OFF +
CONFIG_RO_PUBKEY_STORAGE_OFF);
rv = vb21_is_packed_key_valid(vb21_key);
if (rv) {
CPRINTS("Invalid key (%d)", rv);
return EC_ERROR_VBOOT_KEY;
}
key = (const struct rsa_public_key *)
((const uint8_t *)vb21_key + vb21_key->key_offset);
if (slot == EC_IMAGE_RW_A) {
data = (const uint8_t *)(CONFIG_MAPPED_STORAGE_BASE +
CONFIG_EC_WRITABLE_STORAGE_OFF +
CONFIG_RW_A_STORAGE_OFF);
vb21_sig = (const struct vb21_signature *)(
CONFIG_MAPPED_STORAGE_BASE +
CONFIG_EC_WRITABLE_STORAGE_OFF +
CONFIG_RW_A_SIGN_STORAGE_OFF);
} else {
data = (const uint8_t *)(CONFIG_MAPPED_STORAGE_BASE +
CONFIG_EC_WRITABLE_STORAGE_OFF +
CONFIG_RW_B_STORAGE_OFF);
vb21_sig = (const struct vb21_signature *)(
CONFIG_MAPPED_STORAGE_BASE +
CONFIG_EC_WRITABLE_STORAGE_OFF +
CONFIG_RW_B_SIGN_STORAGE_OFF);
}
rv = vb21_is_signature_valid(vb21_sig, vb21_key);
if (rv) {
CPRINTS("Invalid signature (%d)", rv);
return EC_ERROR_INVAL;
}
sig = (const uint8_t *)vb21_sig + vb21_sig->sig_offset;
len = vb21_sig->data_size;
if (vboot_is_padding_valid(data, len,
CONFIG_RW_SIZE - CONFIG_RW_SIG_SIZE)) {
CPRINTS("Invalid padding");
return EC_ERROR_INVAL;
}
rv = vboot_verify(data, len, key, sig);
if (rv) {
CPRINTS("Invalid data (%d)", rv);
return EC_ERROR_INVAL;
}
CPRINTS("Verified %s", ec_image_to_string(slot));
return EC_SUCCESS;
}
static enum ec_status hc_verify_slot(struct host_cmd_handler_args *args)
{
const struct ec_params_efs_verify *p = args->params;
enum ec_image slot;
switch (p->region) {
case EC_FLASH_REGION_ACTIVE:
slot = system_get_active_copy();
break;
case EC_FLASH_REGION_UPDATE:
slot = system_get_update_copy();
break;
default:
return EC_RES_INVALID_PARAM;
}
return verify_slot(slot) ? EC_RES_ERROR : EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_EFS_VERIFY, hc_verify_slot, EC_VER_MASK(0));
static int verify_and_jump(void)
{
enum ec_image slot;
int rv;
/* 1. Decide which slot to try */
slot = system_get_active_copy();
/* 2. Verify the slot */
rv = verify_slot(slot);
if (rv) {
if (rv == EC_ERROR_VBOOT_KEY)
/* Key error. The other slot isn't worth trying. */
return rv;
slot = system_get_update_copy();
/* TODO(chromium:767050): Skip reading key again. */
rv = verify_slot(slot);
if (rv)
/* Both slots failed */
return rv;
/* Proceed with the other slot. If this slot isn't expected, AP
* will catch it and request recovery after a few attempts. */
if (system_set_active_copy(slot))
CPRINTS("Failed to activate %s",
ec_image_to_string(slot));
}
/* 3. Jump (and reboot) */
rv = system_run_image_copy(slot);
CPRINTS("Failed to jump (%d)", rv);
return rv;
}
/* Request more power: charging battery or more powerful AC adapter */
__overridable void show_power_shortage(void)
{
CPRINTS("%s", __func__);
}
__overridable void show_critical_error(void)
{
CPRINTS("%s", __func__);
}
static bool pd_comm_enabled;
bool vboot_allow_usb_pd(void)
{
return pd_comm_enabled;
}
void vboot_main(void)
{
CPRINTS("Main");
if (system_is_in_rw()) {
/*
* We come here and immediately return. LED shows power shortage
* but it will be immediately corrected if the adapter can
* provide enough power.
*/
CPRINTS("Already in RW. Wait for power...");
show_power_shortage();
return;
}
if (!(crec_flash_get_protect() & EC_FLASH_PROTECT_GPIO_ASSERTED)) {
/*
* If hardware WP is disabled, PD communication is enabled.
* We can return and wait for more power.
* Note: If software WP is disabled, we still perform EFS even
* though PD communication is enabled.
*/
CPRINTS("HW-WP not asserted.");
show_power_shortage();
return;
}
if (system_is_manual_recovery() ||
(system_get_reset_flags() & EC_RESET_FLAG_STAY_IN_RO)) {
if (system_is_manual_recovery())
CPRINTS("Manual recovery");
if (battery_is_present() || has_matrix_keyboard()) {
show_power_shortage();
return;
}
/* We don't request_power because we don't want to assume all
* devices support a non type-c charger. We open up a security
* hole by allowing EC-RO to do PD negotiation but attackers
* don't gain meaningful advantage on devices without a matrix
* keyboard */
CPRINTS("Enable PD comm");
pd_comm_enabled = true;
return;
}
clock_enable_module(MODULE_FAST_CPU, 1);
/* If successful, this won't return. */
verify_and_jump();
clock_enable_module(MODULE_FAST_CPU, 0);
/* Failed to jump. Need recovery. */
show_critical_error();
}
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