u-boot/lib/efi_loader/efi_tcg2.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Defines APIs that allow an OS to interact with UEFI firmware to query
* information about the device.
* https://trustedcomputinggroup.org/resource/tcg-efi-protocol-specification/
*
* Copyright (c) 2020, Linaro Limited
*/
#define LOG_CATEGORY LOGC_EFI
#include <common.h>
#include <dm.h>
#include <efi_loader.h>
#include <efi_variable.h>
#include <efi_tcg2.h>
#include <log.h>
#include <malloc.h>
#include <smbios.h>
#include <version_string.h>
#include <tpm-v2.h>
#include <tpm_api.h>
#include <u-boot/hash-checksum.h>
#include <u-boot/sha1.h>
#include <u-boot/sha256.h>
#include <u-boot/sha512.h>
#include <linux/unaligned/be_byteshift.h>
#include <linux/unaligned/le_byteshift.h>
#include <linux/unaligned/generic.h>
#include <hexdump.h>
/**
* struct event_log_buffer - internal eventlog management structure
*
* @buffer: eventlog buffer
* @final_buffer: finalevent config table buffer
* @pos: current position of 'buffer'
* @final_pos: current position of 'final_buffer'
* @get_event_called: true if GetEventLog has been invoked at least once
* @ebs_called: true if ExitBootServices has been invoked
* @truncated: true if the 'buffer' is truncated
*/
struct event_log_buffer {
void *buffer;
void *final_buffer;
size_t pos; /* eventlog position */
size_t final_pos; /* final events config table position */
size_t last_event_size;
bool get_event_called;
bool ebs_called;
bool truncated;
};
static struct event_log_buffer event_log;
static bool tcg2_efi_app_invoked;
/*
* When requesting TPM2_CAP_TPM_PROPERTIES the value is on a standard offset.
* Since the current tpm2_get_capability() response buffers starts at
* 'union tpmu_capabilities data' of 'struct tpms_capability_data', calculate
* the response size and offset once for all consumers
*/
#define TPM2_RESPONSE_BUFFER_SIZE (sizeof(struct tpms_capability_data) - \
offsetof(struct tpms_capability_data, data))
#define properties_offset (offsetof(struct tpml_tagged_tpm_property, tpm_property) + \
offsetof(struct tpms_tagged_property, value))
static const efi_guid_t efi_guid_tcg2_protocol = EFI_TCG2_PROTOCOL_GUID;
static const efi_guid_t efi_guid_final_events = EFI_TCG2_FINAL_EVENTS_TABLE_GUID;
struct variable_info {
const u16 *name;
bool accept_empty;
u32 pcr_index;
};
static struct variable_info secure_variables[] = {
{u"SecureBoot", true, 7},
{u"PK", true, 7},
{u"KEK", true, 7},
{u"db", true, 7},
{u"dbx", true, 7},
{u"dbt", false, 7},
{u"dbr", false, 7},
{u"DeployedMode", false, 1},
{u"AuditMode", false, 1},
};
static bool is_tcg2_protocol_installed(void)
{
struct efi_handler *handler;
efi_status_t ret;
ret = efi_search_protocol(efi_root, &efi_guid_tcg2_protocol, &handler);
return ret == EFI_SUCCESS;
}
/* tcg2_agile_log_append - Append an agile event to an eventlog
*
* @pcr_index: PCR index
* @event_type: type of event added
* @digest_list: list of digest algorithms to add
* @size: size of event
* @event: event to add
* @log: log buffer to append the event
*
* @Return: status code
*/
static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type,
struct tpml_digest_values *digest_list,
u32 size, u8 event[])
{
void *log = (void *)((uintptr_t)event_log.buffer + event_log.pos);
u32 event_size = size + tcg2_event_get_size(digest_list);
struct efi_tcg2_final_events_table *final_event;
efi_status_t ret = EFI_SUCCESS;
/* if ExitBootServices hasn't been called update the normal log */
if (!event_log.ebs_called) {
if (event_log.truncated ||
event_log.pos + event_size > TPM2_EVENT_LOG_SIZE) {
event_log.truncated = true;
return EFI_VOLUME_FULL;
}
tcg2_log_append(pcr_index, event_type, digest_list, size, event, log);
event_log.pos += event_size;
event_log.last_event_size = event_size;
}
if (!event_log.get_event_called)
return ret;
/* if GetEventLog has been called update FinalEventLog as well */
if (event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE)
return EFI_VOLUME_FULL;
log = (void *)((uintptr_t)event_log.final_buffer + event_log.final_pos);
tcg2_log_append(pcr_index, event_type, digest_list, size, event, log);
final_event = event_log.final_buffer;
final_event->number_of_events++;
event_log.final_pos += event_size;
return ret;
}
/**
* tpm2_get_max_command_size() - get the supported max command size
*
* @dev: TPM device
* @max_command_size: output buffer for the size
*
* Return: 0 on success, -1 on error
*/
static int tpm2_get_max_command_size(struct udevice *dev, u16 *max_command_size)
{
u8 response[TPM2_RESPONSE_BUFFER_SIZE];
u32 ret;
memset(response, 0, sizeof(response));
ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
TPM2_PT_MAX_COMMAND_SIZE, response, 1);
if (ret)
return -1;
*max_command_size = (uint16_t)get_unaligned_be32(response +
properties_offset);
return 0;
}
/**
* tpm2_get_max_response_size() - get the supported max response size
*
* @dev: TPM device
* @max_response_size: output buffer for the size
*
* Return: 0 on success, -1 on error
*/
static int tpm2_get_max_response_size(struct udevice *dev,
u16 *max_response_size)
{
u8 response[TPM2_RESPONSE_BUFFER_SIZE];
u32 ret;
memset(response, 0, sizeof(response));
ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
TPM2_PT_MAX_RESPONSE_SIZE, response, 1);
if (ret)
return -1;
*max_response_size = (uint16_t)get_unaligned_be32(response +
properties_offset);
return 0;
}
/**
* tpm2_get_manufacturer_id() - get the manufacturer ID
*
* @dev: TPM device
* @manufacturer_id: output buffer for the id
*
* Return: 0 on success, -1 on error
*/
static int tpm2_get_manufacturer_id(struct udevice *dev, u32 *manufacturer_id)
{
u8 response[TPM2_RESPONSE_BUFFER_SIZE];
u32 ret;
memset(response, 0, sizeof(response));
ret = tpm2_get_capability(dev, TPM2_CAP_TPM_PROPERTIES,
TPM2_PT_MANUFACTURER, response, 1);
if (ret)
return -1;
*manufacturer_id = get_unaligned_be32(response + properties_offset);
return 0;
}
/**
* efi_tcg2_get_capability() - protocol capability information and state information
*
* @this: TCG2 protocol instance
* @capability: caller allocated memory with size field to the size of
* the structure allocated
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_get_capability(struct efi_tcg2_protocol *this,
struct efi_tcg2_boot_service_capability *capability)
{
struct udevice *dev;
efi_status_t efi_ret;
int ret;
EFI_ENTRY("%p, %p", this, capability);
if (!this || !capability) {
efi_ret = EFI_INVALID_PARAMETER;
goto out;
}
if (capability->size < BOOT_SERVICE_CAPABILITY_MIN) {
capability->size = BOOT_SERVICE_CAPABILITY_MIN;
efi_ret = EFI_BUFFER_TOO_SMALL;
goto out;
}
if (capability->size < sizeof(*capability)) {
capability->size = sizeof(*capability);
efi_ret = EFI_BUFFER_TOO_SMALL;
goto out;
}
capability->structure_version.major = 1;
capability->structure_version.minor = 1;
capability->protocol_version.major = 1;
capability->protocol_version.minor = 1;
efi_ret = tcg2_platform_get_tpm2(&dev);
if (efi_ret != EFI_SUCCESS) {
capability->supported_event_logs = 0;
capability->hash_algorithm_bitmap = 0;
capability->tpm_present_flag = false;
capability->max_command_size = 0;
capability->max_response_size = 0;
capability->manufacturer_id = 0;
capability->number_of_pcr_banks = 0;
capability->active_pcr_banks = 0;
efi_ret = EFI_SUCCESS;
goto out;
}
/* We only allow a TPMv2 device to register the EFI protocol */
capability->supported_event_logs = TCG2_EVENT_LOG_FORMAT_TCG_2;
capability->tpm_present_flag = true;
/* Supported and active PCRs */
capability->hash_algorithm_bitmap = 0;
capability->active_pcr_banks = 0;
ret = tpm2_get_pcr_info(dev, &capability->hash_algorithm_bitmap,
&capability->active_pcr_banks,
&capability->number_of_pcr_banks);
if (ret) {
efi_ret = EFI_DEVICE_ERROR;
goto out;
}
/* Max command size */
ret = tpm2_get_max_command_size(dev, &capability->max_command_size);
if (ret) {
efi_ret = EFI_DEVICE_ERROR;
goto out;
}
/* Max response size */
ret = tpm2_get_max_response_size(dev, &capability->max_response_size);
if (ret) {
efi_ret = EFI_DEVICE_ERROR;
goto out;
}
/* Manufacturer ID */
ret = tpm2_get_manufacturer_id(dev, &capability->manufacturer_id);
if (ret) {
efi_ret = EFI_DEVICE_ERROR;
goto out;
}
return EFI_EXIT(EFI_SUCCESS);
out:
return EFI_EXIT(efi_ret);
}
/**
* efi_tcg2_get_eventlog() - retrieve the the address of an event log and its
* last entry
*
* @this: TCG2 protocol instance
* @log_format: type of event log format
* @event_log_location: pointer to the memory address of the event log
* @event_log_last_entry: pointer to the address of the start of the last
* entry in the event log in memory, if log contains
* more than 1 entry
* @event_log_truncated: set to true, if the Event Log is missing at i
* least one entry
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_get_eventlog(struct efi_tcg2_protocol *this,
efi_tcg_event_log_format log_format,
u64 *event_log_location, u64 *event_log_last_entry,
bool *event_log_truncated)
{
efi_status_t ret = EFI_SUCCESS;
struct udevice *dev;
EFI_ENTRY("%p, %u, %p, %p, %p", this, log_format, event_log_location,
event_log_last_entry, event_log_truncated);
if (!this || !event_log_location || !event_log_last_entry ||
!event_log_truncated) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
/* Only support TPMV2 */
if (log_format != TCG2_EVENT_LOG_FORMAT_TCG_2) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS) {
event_log_location = NULL;
event_log_last_entry = NULL;
*event_log_truncated = false;
ret = EFI_SUCCESS;
goto out;
}
*event_log_location = (uintptr_t)event_log.buffer;
*event_log_last_entry = (uintptr_t)(event_log.buffer + event_log.pos -
event_log.last_event_size);
*event_log_truncated = event_log.truncated;
event_log.get_event_called = true;
out:
return EFI_EXIT(ret);
}
/**
* tcg2_hash_pe_image() - calculate PE/COFF image hash
*
* @efi: pointer to the EFI binary
* @efi_size: size of @efi binary
* @digest_list: list of digest algorithms to extend
*
* Return: status code
*/
static efi_status_t tcg2_hash_pe_image(void *efi, u64 efi_size,
struct tpml_digest_values *digest_list)
{
WIN_CERTIFICATE *wincerts = NULL;
size_t wincerts_len;
struct efi_image_regions *regs = NULL;
void *new_efi = NULL;
u8 hash[TPM2_SHA512_DIGEST_SIZE];
struct udevice *dev;
efi_status_t ret;
u32 active;
int i;
new_efi = efi_prepare_aligned_image(efi, &efi_size);
if (!new_efi)
return EFI_OUT_OF_RESOURCES;
if (!efi_image_parse(new_efi, efi_size, &regs, &wincerts,
&wincerts_len)) {
log_err("Parsing PE executable image failed\n");
ret = EFI_UNSUPPORTED;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
ret = tcg2_get_active_pcr_banks(dev, &active);
if (ret != EFI_SUCCESS) {
goto out;
}
digest_list->count = 0;
for (i = 0; i < ARRAY_SIZE(tpm2_supported_algorithms); i++) {
u16 hash_alg = tpm2_supported_algorithms[i];
if (!(active & tpm2_algorithm_to_mask(hash_alg)))
continue;
switch (hash_alg) {
case TPM2_ALG_SHA1:
hash_calculate("sha1", regs->reg, regs->num, hash);
break;
case TPM2_ALG_SHA256:
hash_calculate("sha256", regs->reg, regs->num, hash);
break;
case TPM2_ALG_SHA384:
hash_calculate("sha384", regs->reg, regs->num, hash);
break;
case TPM2_ALG_SHA512:
hash_calculate("sha512", regs->reg, regs->num, hash);
break;
default:
continue;
}
digest_list->digests[digest_list->count].hash_alg = hash_alg;
memcpy(&digest_list->digests[digest_list->count].digest, hash,
(u32)tpm2_algorithm_to_len(hash_alg));
digest_list->count++;
}
out:
if (new_efi != efi)
free(new_efi);
free(regs);
return ret;
}
/**
* tcg2_measure_pe_image() - measure PE/COFF image
*
* @efi: pointer to the EFI binary
* @efi_size: size of @efi binary
* @handle: loaded image handle
* @loaded_image: loaded image protocol
*
* Return: status code
*/
efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
struct efi_loaded_image_obj *handle,
struct efi_loaded_image *loaded_image)
{
struct tpml_digest_values digest_list;
efi_status_t ret;
struct udevice *dev;
u32 pcr_index, event_type, event_size;
struct uefi_image_load_event *image_load_event;
struct efi_device_path *device_path;
u32 device_path_length;
IMAGE_DOS_HEADER *dos;
IMAGE_NT_HEADERS32 *nt;
struct efi_handler *handler;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return EFI_SECURITY_VIOLATION;
switch (handle->image_type) {
case IMAGE_SUBSYSTEM_EFI_APPLICATION:
pcr_index = 4;
event_type = EV_EFI_BOOT_SERVICES_APPLICATION;
break;
case IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER:
pcr_index = 2;
event_type = EV_EFI_BOOT_SERVICES_DRIVER;
break;
case IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER:
pcr_index = 2;
event_type = EV_EFI_RUNTIME_SERVICES_DRIVER;
break;
default:
return EFI_UNSUPPORTED;
}
ret = tcg2_hash_pe_image(efi, efi_size, &digest_list);
if (ret != EFI_SUCCESS)
return ret;
ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
if (ret != EFI_SUCCESS)
return ret;
ret = efi_search_protocol(&handle->header,
&efi_guid_loaded_image_device_path, &handler);
if (ret != EFI_SUCCESS)
return ret;
device_path = handler->protocol_interface;
device_path_length = efi_dp_size(device_path);
if (device_path_length > 0) {
/* add end node size */
device_path_length += sizeof(struct efi_device_path);
}
event_size = sizeof(struct uefi_image_load_event) + device_path_length;
image_load_event = calloc(1, event_size);
if (!image_load_event)
return EFI_OUT_OF_RESOURCES;
image_load_event->image_location_in_memory = (uintptr_t)efi;
image_load_event->image_length_in_memory = efi_size;
image_load_event->length_of_device_path = device_path_length;
dos = (IMAGE_DOS_HEADER *)efi;
nt = (IMAGE_NT_HEADERS32 *)(efi + dos->e_lfanew);
if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR64_MAGIC) {
IMAGE_NT_HEADERS64 *nt64 = (IMAGE_NT_HEADERS64 *)nt;
image_load_event->image_link_time_address =
nt64->OptionalHeader.ImageBase;
} else if (nt->OptionalHeader.Magic == IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
image_load_event->image_link_time_address =
nt->OptionalHeader.ImageBase;
} else {
ret = EFI_INVALID_PARAMETER;
goto out;
}
/* device_path_length might be zero */
memcpy(image_load_event->device_path, device_path, device_path_length);
ret = tcg2_agile_log_append(pcr_index, event_type, &digest_list,
event_size, (u8 *)image_load_event);
out:
free(image_load_event);
return ret;
}
/**
* efi_tcg2_hash_log_extend_event() - extend and optionally log events
*
* @this: TCG2 protocol instance
* @flags: bitmap providing additional information on the
* operation
* @data_to_hash: physical address of the start of the data buffer
* to be hashed
* @data_to_hash_len: the length in bytes of the buffer referenced by
* data_to_hash
* @efi_tcg_event: pointer to data buffer containing information
* about the event
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_hash_log_extend_event(struct efi_tcg2_protocol *this, u64 flags,
u64 data_to_hash, u64 data_to_hash_len,
struct efi_tcg2_event *efi_tcg_event)
{
struct udevice *dev;
efi_status_t ret;
u32 event_type, pcr_index, event_size;
struct tpml_digest_values digest_list;
EFI_ENTRY("%p, %llu, %llu, %llu, %p", this, flags, data_to_hash,
data_to_hash_len, efi_tcg_event);
if (!this || !data_to_hash || !efi_tcg_event) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
if (efi_tcg_event->size < efi_tcg_event->header.header_size +
sizeof(u32)) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
if (efi_tcg_event->header.pcr_index > EFI_TCG2_MAX_PCR_INDEX) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
/*
* if PE_COFF_IMAGE is set we need to make sure the image is not
* corrupted, verify it and hash the PE/COFF image in accordance with
* the procedure specified in "Calculating the PE Image Hash"
* section of the "Windows Authenticode Portable Executable Signature
* Format"
*/
if (flags & PE_COFF_IMAGE) {
IMAGE_NT_HEADERS32 *nt;
ret = efi_check_pe((void *)(uintptr_t)data_to_hash,
data_to_hash_len, (void **)&nt);
if (ret != EFI_SUCCESS) {
log_err("Not a valid PE-COFF file\n");
ret = EFI_UNSUPPORTED;
goto out;
}
ret = tcg2_hash_pe_image((void *)(uintptr_t)data_to_hash,
data_to_hash_len, &digest_list);
} else {
ret = tcg2_create_digest(dev, (u8 *)(uintptr_t)data_to_hash,
data_to_hash_len, &digest_list);
}
if (ret != EFI_SUCCESS)
goto out;
pcr_index = efi_tcg_event->header.pcr_index;
event_type = efi_tcg_event->header.event_type;
ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
if (ret != EFI_SUCCESS)
goto out;
if (flags & EFI_TCG2_EXTEND_ONLY) {
if (event_log.truncated)
ret = EFI_VOLUME_FULL;
goto out;
}
/*
* The efi_tcg_event size includes the size component and the
* headersize
*/
event_size = efi_tcg_event->size - sizeof(efi_tcg_event->size) -
efi_tcg_event->header.header_size;
ret = tcg2_agile_log_append(pcr_index, event_type, &digest_list,
event_size, efi_tcg_event->event);
out:
return EFI_EXIT(ret);
}
/**
* efi_tcg2_submit_command() - Send command to the TPM
*
* @this: TCG2 protocol instance
* @input_param_block_size: size of the TPM input parameter block
* @input_param_block: pointer to the TPM input parameter block
* @output_param_block_size: size of the TPM output parameter block
* @output_param_block: pointer to the TPM output parameter block
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_submit_command(struct efi_tcg2_protocol *this,
u32 input_param_block_size,
u8 *input_param_block,
u32 output_param_block_size,
u8 *output_param_block)
{
struct udevice *dev;
efi_status_t ret;
u32 rc;
size_t resp_buf_size = output_param_block_size;
EFI_ENTRY("%p, %u, %p, %u, %p", this, input_param_block_size,
input_param_block, output_param_block_size, output_param_block);
if (!this || !input_param_block || !input_param_block_size) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
rc = tpm2_submit_command(dev, input_param_block,
output_param_block, &resp_buf_size);
if (rc) {
ret = (rc == -ENOSPC) ? EFI_OUT_OF_RESOURCES : EFI_DEVICE_ERROR;
goto out;
}
out:
return EFI_EXIT(ret);
}
/**
* efi_tcg2_get_active_pcr_banks() - returns the currently active PCR banks
*
* @this: TCG2 protocol instance
* @active_pcr_banks: pointer for receiving the bitmap of currently
* active PCR banks
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_get_active_pcr_banks(struct efi_tcg2_protocol *this,
u32 *active_pcr_banks)
{
struct udevice *dev;
efi_status_t ret;
EFI_ENTRY("%p, %p", this, active_pcr_banks);
if (!this || !active_pcr_banks) {
ret = EFI_INVALID_PARAMETER;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
ret = tcg2_get_active_pcr_banks(dev, active_pcr_banks);
out:
return EFI_EXIT(ret);
}
/**
* efi_tcg2_set_active_pcr_banks() - sets the currently active PCR banks
*
* @this: TCG2 protocol instance
* @active_pcr_banks: bitmap of the requested active PCR banks
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_set_active_pcr_banks(__maybe_unused struct efi_tcg2_protocol *this,
u32 __maybe_unused active_pcr_banks)
{
return EFI_UNSUPPORTED;
}
/**
* efi_tcg2_get_result_of_set_active_pcr_banks() - retrieve result for previous
* set_active_pcr_banks()
*
* @this: TCG2 protocol instance
* @operation_present: non-zero value to indicate a
* set_active_pcr_banks operation was
* invoked during last boot
* @response: result value could be returned
*
* Return: status code
*/
static efi_status_t EFIAPI
efi_tcg2_get_result_of_set_active_pcr_banks(__maybe_unused struct efi_tcg2_protocol *this,
u32 __maybe_unused *operation_present,
u32 __maybe_unused *response)
{
return EFI_UNSUPPORTED;
}
static const struct efi_tcg2_protocol efi_tcg2_protocol = {
.get_capability = efi_tcg2_get_capability,
.get_eventlog = efi_tcg2_get_eventlog,
.hash_log_extend_event = efi_tcg2_hash_log_extend_event,
.submit_command = efi_tcg2_submit_command,
.get_active_pcr_banks = efi_tcg2_get_active_pcr_banks,
.set_active_pcr_banks = efi_tcg2_set_active_pcr_banks,
.get_result_of_set_active_pcr_banks = efi_tcg2_get_result_of_set_active_pcr_banks,
};
/**
* tcg2_uninit - remove the final event table and free efi memory on failures
*/
void tcg2_uninit(void)
{
efi_status_t ret;
ret = efi_install_configuration_table(&efi_guid_final_events, NULL);
if (ret != EFI_SUCCESS)
log_err("Failed to delete final events config table\n");
efi_free_pool(event_log.buffer);
event_log.buffer = NULL;
efi_free_pool(event_log.final_buffer);
event_log.final_buffer = NULL;
if (!is_tcg2_protocol_installed())
return;
ret = efi_uninstall_multiple_protocol_interfaces(efi_root, &efi_guid_tcg2_protocol,
&efi_tcg2_protocol, NULL);
if (ret != EFI_SUCCESS)
log_err("Failed to remove EFI TCG2 protocol\n");
}
/**
* create_final_event() - Create the final event and install the config
* defined by the TCG EFI spec
*/
static efi_status_t create_final_event(void)
{
struct efi_tcg2_final_events_table *final_event;
efi_status_t ret;
/*
* All events generated after the invocation of
* EFI_TCG2_GET_EVENT_LOGS need to be stored in an instance of an
* EFI_CONFIGURATION_TABLE
*/
ret = efi_allocate_pool(EFI_ACPI_MEMORY_NVS, TPM2_EVENT_LOG_SIZE,
&event_log.final_buffer);
if (ret != EFI_SUCCESS)
goto out;
memset(event_log.final_buffer, 0xff, TPM2_EVENT_LOG_SIZE);
final_event = event_log.final_buffer;
final_event->number_of_events = 0;
final_event->version = EFI_TCG2_FINAL_EVENTS_TABLE_VERSION;
event_log.final_pos = sizeof(*final_event);
ret = efi_install_configuration_table(&efi_guid_final_events,
final_event);
if (ret != EFI_SUCCESS) {
efi_free_pool(event_log.final_buffer);
event_log.final_buffer = NULL;
}
out:
return ret;
}
/**
* measure_event() - common function to add event log and extend PCR
*
* @dev: TPM device
* @pcr_index: PCR index
* @event_type: type of event added
* @size: event size
* @event: event data
*
* Return: status code
*/
static efi_status_t measure_event(struct udevice *dev, u32 pcr_index,
u32 event_type, u32 size, u8 event[])
{
struct tpml_digest_values digest_list;
efi_status_t ret;
ret = tcg2_create_digest(dev, event, size, &digest_list);
if (ret != EFI_SUCCESS)
goto out;
ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
if (ret != EFI_SUCCESS)
goto out;
ret = tcg2_agile_log_append(pcr_index, event_type, &digest_list,
size, event);
out:
return ret;
}
/**
* efi_append_scrtm_version - Append an S-CRTM EV_S_CRTM_VERSION event on the
* eventlog and extend the PCRs
*
* @dev: TPM device
*
* @Return: status code
*/
static efi_status_t efi_append_scrtm_version(struct udevice *dev)
{
efi_status_t ret;
ret = measure_event(dev, 0, EV_S_CRTM_VERSION,
strlen(version_string) + 1, (u8 *)version_string);
return ret;
}
/**
* efi_init_event_log() - initialize an eventlog
*
* Return: status code
*/
static efi_status_t efi_init_event_log(void)
{
/*
* vendor_info_size is currently set to 0, we need to change the length
* and allocate the flexible array member if this changes
*/
struct tcg2_event_log elog;
struct udevice *dev;
efi_status_t ret;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return ret;
ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA, TPM2_EVENT_LOG_SIZE,
(void **)&event_log.buffer);
if (ret != EFI_SUCCESS)
return ret;
/*
* initialize log area as 0xff so the OS can easily figure out the
* last log entry
*/
memset(event_log.buffer, 0xff, TPM2_EVENT_LOG_SIZE);
/*
* The log header is defined to be in SHA1 event log entry format.
* Setup event header
*/
event_log.pos = 0;
event_log.last_event_size = 0;
event_log.get_event_called = false;
event_log.ebs_called = false;
event_log.truncated = false;
/*
* Check if earlier firmware have passed any eventlog. Different
* platforms can use different ways to do so.
*/
elog.log = event_log.buffer;
elog.log_size = TPM2_EVENT_LOG_SIZE;
ret = tcg2_log_prepare_buffer(dev, &elog, false);
if (ret != EFI_SUCCESS)
goto free_pool;
event_log.pos = elog.log_position;
/*
* Add SCRTM version to the log if previous firmmware
* doesn't pass an eventlog.
*/
if (!elog.found)
ret = efi_append_scrtm_version(dev);
ret = create_final_event();
if (ret != EFI_SUCCESS)
goto free_pool;
return ret;
free_pool:
efi_free_pool(event_log.buffer);
event_log.buffer = NULL;
return ret;
}
/**
* tcg2_measure_variable() - add variable event log and extend PCR
*
* @dev: TPM device
* @pcr_index: PCR index
* @event_type: type of event added
* @var_name: variable name
* @guid: guid
* @data_size: variable data size
* @data: variable data
*
* Return: status code
*/
static efi_status_t tcg2_measure_variable(struct udevice *dev, u32 pcr_index,
u32 event_type, const u16 *var_name,
const efi_guid_t *guid,
efi_uintn_t data_size, u8 *data)
{
u32 event_size;
efi_status_t ret;
struct efi_tcg2_uefi_variable_data *event;
event_size = sizeof(event->variable_name) +
sizeof(event->unicode_name_length) +
sizeof(event->variable_data_length) +
(u16_strlen(var_name) * sizeof(u16)) + data_size;
event = malloc(event_size);
if (!event)
return EFI_OUT_OF_RESOURCES;
guidcpy(&event->variable_name, guid);
event->unicode_name_length = u16_strlen(var_name);
event->variable_data_length = data_size;
memcpy(event->unicode_name, var_name,
(event->unicode_name_length * sizeof(u16)));
if (data) {
memcpy((u16 *)event->unicode_name + event->unicode_name_length,
data, data_size);
}
ret = measure_event(dev, pcr_index, event_type, event_size,
(u8 *)event);
free(event);
return ret;
}
/**
* tcg2_measure_boot_variable() - measure boot variables
*
* @dev: TPM device
*
* Return: status code
*/
static efi_status_t tcg2_measure_boot_variable(struct udevice *dev)
{
u16 *boot_order;
u16 *boot_index;
u16 var_name[] = u"BootOrder";
u16 boot_name[] = u"Boot####";
u8 *bootvar;
efi_uintn_t var_data_size;
u32 count, i;
efi_status_t ret;
boot_order = efi_get_var(var_name, &efi_global_variable_guid,
&var_data_size);
if (!boot_order) {
/* If "BootOrder" is not defined, skip the boot variable measurement */
return EFI_SUCCESS;
}
ret = tcg2_measure_variable(dev, 1, EV_EFI_VARIABLE_BOOT2, var_name,
&efi_global_variable_guid, var_data_size,
(u8 *)boot_order);
if (ret != EFI_SUCCESS)
goto error;
count = var_data_size / sizeof(*boot_order);
boot_index = boot_order;
for (i = 0; i < count; i++) {
efi_create_indexed_name(boot_name, sizeof(boot_name),
"Boot", *boot_index++);
bootvar = efi_get_var(boot_name, &efi_global_variable_guid,
&var_data_size);
if (!bootvar) {
log_debug("%ls not found\n", boot_name);
continue;
}
ret = tcg2_measure_variable(dev, 1, EV_EFI_VARIABLE_BOOT2,
boot_name,
&efi_global_variable_guid,
var_data_size, bootvar);
free(bootvar);
if (ret != EFI_SUCCESS)
goto error;
}
error:
free(boot_order);
return ret;
}
/**
* tcg2_measure_smbios() - measure smbios table
*
* @dev: TPM device
* @entry: pointer to the smbios_entry structure
*
* Return: status code
*/
static efi_status_t
tcg2_measure_smbios(struct udevice *dev,
const struct smbios_entry *entry)
{
efi_status_t ret;
struct smbios_header *smbios_copy;
struct smbios_handoff_table_pointers2 *event = NULL;
u32 event_size;
/*
* TCG PC Client PFP Spec says
* "SMBIOS structures that contain static configuration information
* (e.g. Platform Manufacturer Enterprise Number assigned by IANA,
* platform model number, Vendor and Device IDs for each SMBIOS table)
* that is relevant to the security of the platform MUST be measured".
* Device dependent parameters such as serial number are cleared to
* zero or spaces for the measurement.
*/
event_size = sizeof(struct smbios_handoff_table_pointers2) +
FIELD_SIZEOF(struct efi_configuration_table, guid) +
entry->struct_table_length;
event = calloc(1, event_size);
if (!event) {
ret = EFI_OUT_OF_RESOURCES;
goto out;
}
event->table_description_size = sizeof(SMBIOS_HANDOFF_TABLE_DESC);
memcpy(event->table_description, SMBIOS_HANDOFF_TABLE_DESC,
sizeof(SMBIOS_HANDOFF_TABLE_DESC));
put_unaligned_le64(1, &event->number_of_tables);
guidcpy(&event->table_entry[0].guid, &smbios_guid);
smbios_copy = (struct smbios_header *)((uintptr_t)&event->table_entry[0].table);
memcpy(&event->table_entry[0].table,
(void *)((uintptr_t)entry->struct_table_address),
entry->struct_table_length);
smbios_prepare_measurement(entry, smbios_copy);
ret = measure_event(dev, 1, EV_EFI_HANDOFF_TABLES2, event_size,
(u8 *)event);
if (ret != EFI_SUCCESS)
goto out;
out:
free(event);
return ret;
}
/**
* find_smbios_table() - find smbios table
*
* Return: pointer to the smbios table
*/
static void *find_smbios_table(void)
{
u32 i;
for (i = 0; i < systab.nr_tables; i++) {
if (!guidcmp(&smbios_guid, &systab.tables[i].guid))
return systab.tables[i].table;
}
return NULL;
}
/**
* tcg2_measure_gpt_table() - measure gpt table
*
* @dev: TPM device
* @loaded_image: handle to the loaded image
*
* Return: status code
*/
static efi_status_t
tcg2_measure_gpt_data(struct udevice *dev,
struct efi_loaded_image_obj *loaded_image)
{
efi_status_t ret;
efi_handle_t handle;
struct efi_handler *dp_handler, *io_handler;
struct efi_device_path *orig_device_path;
struct efi_device_path *device_path;
struct efi_device_path *dp;
struct efi_block_io *block_io;
struct efi_gpt_data *event = NULL;
efi_guid_t null_guid = NULL_GUID;
gpt_header *gpt_h;
gpt_entry *entry = NULL;
gpt_entry *gpt_e;
u32 num_of_valid_entry = 0;
u32 event_size;
u32 i;
u32 total_gpt_entry_size;
ret = efi_search_protocol(&loaded_image->header,
&efi_guid_loaded_image_device_path,
&dp_handler);
if (ret != EFI_SUCCESS)
return ret;
orig_device_path = dp_handler->protocol_interface;
if (!orig_device_path) /* no device path, skip GPT measurement */
return EFI_SUCCESS;
device_path = efi_dp_dup(orig_device_path);
if (!device_path)
return EFI_OUT_OF_RESOURCES;
dp = search_gpt_dp_node(device_path);
if (!dp) {
/* no GPT device path node found, skip GPT measurement */
ret = EFI_SUCCESS;
goto out1;
}
/* read GPT header */
dp->type = DEVICE_PATH_TYPE_END;
dp->sub_type = DEVICE_PATH_SUB_TYPE_END;
dp = device_path;
ret = EFI_CALL(systab.boottime->locate_device_path(&efi_block_io_guid,
&dp, &handle));
if (ret != EFI_SUCCESS)
goto out1;
ret = efi_search_protocol(handle, &efi_block_io_guid, &io_handler);
if (ret != EFI_SUCCESS)
goto out1;
block_io = io_handler->protocol_interface;
gpt_h = memalign(block_io->media->io_align, block_io->media->block_size);
if (!gpt_h) {
ret = EFI_OUT_OF_RESOURCES;
goto out2;
}
ret = block_io->read_blocks(block_io, block_io->media->media_id, 1,
block_io->media->block_size, gpt_h);
if (ret != EFI_SUCCESS)
goto out2;
/* read GPT entry */
total_gpt_entry_size = gpt_h->num_partition_entries *
gpt_h->sizeof_partition_entry;
entry = memalign(block_io->media->io_align, total_gpt_entry_size);
if (!entry) {
ret = EFI_OUT_OF_RESOURCES;
goto out2;
}
ret = block_io->read_blocks(block_io, block_io->media->media_id,
gpt_h->partition_entry_lba,
total_gpt_entry_size, entry);
if (ret != EFI_SUCCESS)
goto out2;
/* count valid GPT entry */
gpt_e = entry;
for (i = 0; i < gpt_h->num_partition_entries; i++) {
if (guidcmp(&null_guid, &gpt_e->partition_type_guid))
num_of_valid_entry++;
gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
}
/* prepare event data for measurement */
event_size = sizeof(struct efi_gpt_data) +
(num_of_valid_entry * gpt_h->sizeof_partition_entry);
event = calloc(1, event_size);
if (!event) {
ret = EFI_OUT_OF_RESOURCES;
goto out2;
}
memcpy(event, gpt_h, sizeof(gpt_header));
put_unaligned_le64(num_of_valid_entry, &event->number_of_partitions);
/* copy valid GPT entry */
gpt_e = entry;
num_of_valid_entry = 0;
for (i = 0; i < gpt_h->num_partition_entries; i++) {
if (guidcmp(&null_guid, &gpt_e->partition_type_guid)) {
memcpy((u8 *)event->partitions +
(num_of_valid_entry * gpt_h->sizeof_partition_entry),
gpt_e, gpt_h->sizeof_partition_entry);
num_of_valid_entry++;
}
gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
}
ret = measure_event(dev, 5, EV_EFI_GPT_EVENT, event_size, (u8 *)event);
out2:
free(gpt_h);
free(entry);
free(event);
out1:
efi_free_pool(device_path);
return ret;
}
/* Return the byte size of reserved map area in DTB or -1 upon error */
static ssize_t size_of_rsvmap(void *dtb)
{
struct fdt_reserve_entry e;
ssize_t size_max;
ssize_t size;
u8 *rsvmap_base;
rsvmap_base = (u8 *)dtb + fdt_off_mem_rsvmap(dtb);
size_max = fdt_totalsize(dtb) - fdt_off_mem_rsvmap(dtb);
size = 0;
do {
memcpy(&e, rsvmap_base + size, sizeof(e));
size += sizeof(e);
if (size > size_max)
return -1;
} while (e.size);
return size;
}
/**
* efi_tcg2_measure_dtb() - measure DTB passed to the OS
*
* @dtb: pointer to the device tree blob
*
* Return: status code
*/
efi_status_t efi_tcg2_measure_dtb(void *dtb)
{
struct uefi_platform_firmware_blob2 *blob;
struct fdt_header *header;
sha256_context hash_ctx;
struct udevice *dev;
ssize_t rsvmap_size;
efi_status_t ret;
u32 event_size;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return EFI_SECURITY_VIOLATION;
rsvmap_size = size_of_rsvmap(dtb);
if (rsvmap_size < 0)
return EFI_SECURITY_VIOLATION;
event_size = sizeof(*blob) + sizeof(EFI_DTB_EVENT_STRING) + SHA256_SUM_LEN;
blob = calloc(1, event_size);
if (!blob)
return EFI_OUT_OF_RESOURCES;
blob->blob_description_size = sizeof(EFI_DTB_EVENT_STRING);
memcpy(blob->data, EFI_DTB_EVENT_STRING, blob->blob_description_size);
/* Measure populated areas of the DTB */
header = dtb;
sha256_starts(&hash_ctx);
sha256_update(&hash_ctx, (u8 *)header, sizeof(struct fdt_header));
sha256_update(&hash_ctx, (u8 *)dtb + fdt_off_dt_struct(dtb), fdt_size_dt_strings(dtb));
sha256_update(&hash_ctx, (u8 *)dtb + fdt_off_dt_strings(dtb), fdt_size_dt_struct(dtb));
sha256_update(&hash_ctx, (u8 *)dtb + fdt_off_mem_rsvmap(dtb), rsvmap_size);
sha256_finish(&hash_ctx, blob->data + blob->blob_description_size);
ret = measure_event(dev, 0, EV_POST_CODE, event_size, (u8 *)blob);
free(blob);
return ret;
}
/**
* efi_tcg2_measure_efi_app_invocation() - measure efi app invocation
*
* Return: status code
*/
efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *handle)
{
efi_status_t ret;
u32 pcr_index;
struct udevice *dev;
u32 event = 0;
struct smbios_entry *entry;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
if (tcg2_efi_app_invoked)
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return EFI_SECURITY_VIOLATION;
ret = tcg2_measure_boot_variable(dev);
if (ret != EFI_SUCCESS)
goto out;
ret = measure_event(dev, 4, EV_EFI_ACTION,
strlen(EFI_CALLING_EFI_APPLICATION),
(u8 *)EFI_CALLING_EFI_APPLICATION);
if (ret != EFI_SUCCESS)
goto out;
entry = (struct smbios_entry *)find_smbios_table();
if (entry) {
ret = tcg2_measure_smbios(dev, entry);
if (ret != EFI_SUCCESS)
goto out;
}
ret = tcg2_measure_gpt_data(dev, handle);
if (ret != EFI_SUCCESS)
goto out;
for (pcr_index = 0; pcr_index <= 7; pcr_index++) {
ret = measure_event(dev, pcr_index, EV_SEPARATOR,
sizeof(event), (u8 *)&event);
if (ret != EFI_SUCCESS)
goto out;
}
tcg2_efi_app_invoked = true;
out:
return ret;
}
/**
* efi_tcg2_measure_efi_app_exit() - measure efi app exit
*
* Return: status code
*/
efi_status_t efi_tcg2_measure_efi_app_exit(void)
{
efi_status_t ret;
struct udevice *dev;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return ret;
ret = measure_event(dev, 4, EV_EFI_ACTION,
strlen(EFI_RETURNING_FROM_EFI_APPLICATION),
(u8 *)EFI_RETURNING_FROM_EFI_APPLICATION);
return ret;
}
/**
* efi_tcg2_notify_exit_boot_services() - ExitBootService callback
*
* @event: callback event
* @context: callback context
*/
static void EFIAPI
efi_tcg2_notify_exit_boot_services(struct efi_event *event, void *context)
{
efi_status_t ret;
struct udevice *dev;
EFI_ENTRY("%p, %p", event, context);
event_log.ebs_called = true;
if (!is_tcg2_protocol_installed()) {
ret = EFI_SUCCESS;
goto out;
}
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
ret = measure_event(dev, 5, EV_EFI_ACTION,
strlen(EFI_EXIT_BOOT_SERVICES_INVOCATION),
(u8 *)EFI_EXIT_BOOT_SERVICES_INVOCATION);
if (ret != EFI_SUCCESS)
goto out;
ret = measure_event(dev, 5, EV_EFI_ACTION,
strlen(EFI_EXIT_BOOT_SERVICES_SUCCEEDED),
(u8 *)EFI_EXIT_BOOT_SERVICES_SUCCEEDED);
out:
EFI_EXIT(ret);
}
/**
* efi_tcg2_notify_exit_boot_services_failed()
* - notify ExitBootServices() is failed
*
* Return: status code
*/
efi_status_t efi_tcg2_notify_exit_boot_services_failed(void)
{
struct udevice *dev;
efi_status_t ret;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
goto out;
ret = measure_event(dev, 5, EV_EFI_ACTION,
strlen(EFI_EXIT_BOOT_SERVICES_INVOCATION),
(u8 *)EFI_EXIT_BOOT_SERVICES_INVOCATION);
if (ret != EFI_SUCCESS)
goto out;
ret = measure_event(dev, 5, EV_EFI_ACTION,
strlen(EFI_EXIT_BOOT_SERVICES_FAILED),
(u8 *)EFI_EXIT_BOOT_SERVICES_FAILED);
out:
return ret;
}
/**
* tcg2_measure_secure_boot_variable() - measure secure boot variables
*
* @dev: TPM device
*
* Return: status code
*/
static efi_status_t tcg2_measure_secure_boot_variable(struct udevice *dev)
{
u8 *data;
efi_uintn_t data_size;
u32 count, i;
efi_status_t ret;
u8 deployed_mode;
efi_uintn_t size;
u32 deployed_audit_pcr_index = 1;
size = sizeof(deployed_mode);
ret = efi_get_variable_int(u"DeployedMode", &efi_global_variable_guid,
NULL, &size, &deployed_mode, NULL);
if (ret != EFI_SUCCESS || !deployed_mode)
deployed_audit_pcr_index = 7;
count = ARRAY_SIZE(secure_variables);
for (i = 0; i < count; i++) {
const efi_guid_t *guid;
guid = efi_auth_var_get_guid(secure_variables[i].name);
data = efi_get_var(secure_variables[i].name, guid, &data_size);
if (!data && !secure_variables[i].accept_empty)
continue;
if (u16_strcmp(u"DeployedMode", secure_variables[i].name))
secure_variables[i].pcr_index = deployed_audit_pcr_index;
if (u16_strcmp(u"AuditMode", secure_variables[i].name))
secure_variables[i].pcr_index = deployed_audit_pcr_index;
ret = tcg2_measure_variable(dev, secure_variables[i].pcr_index,
EV_EFI_VARIABLE_DRIVER_CONFIG,
secure_variables[i].name, guid,
data_size, data);
free(data);
if (ret != EFI_SUCCESS)
goto error;
}
error:
return ret;
}
/**
* efi_tcg2_do_initial_measurement() - do initial measurement
*
* Return: status code
*/
efi_status_t efi_tcg2_do_initial_measurement(void)
{
efi_status_t ret;
struct udevice *dev;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS)
return EFI_SECURITY_VIOLATION;
ret = tcg2_measure_secure_boot_variable(dev);
if (ret != EFI_SUCCESS)
goto out;
out:
return ret;
}
/**
* efi_tcg2_register() - register EFI_TCG2_PROTOCOL
*
* If a TPM2 device is available, the TPM TCG2 Protocol is registered
*
* Return: status code
*/
efi_status_t efi_tcg2_register(void)
{
efi_status_t ret = EFI_SUCCESS;
struct udevice *dev;
struct efi_event *event;
u32 err;
ret = tcg2_platform_get_tpm2(&dev);
if (ret != EFI_SUCCESS) {
log_warning("Missing TPMv2 device for EFI_TCG_PROTOCOL\n");
return EFI_SUCCESS;
}
/* initialize the TPM as early as possible. */
err = tpm_auto_start(dev);
if (err) {
log_err("TPM startup failed\n");
goto fail;
}
ret = efi_init_event_log();
if (ret != EFI_SUCCESS) {
tcg2_uninit();
goto fail;
}
ret = efi_install_multiple_protocol_interfaces(&efi_root, &efi_guid_tcg2_protocol,
&efi_tcg2_protocol, NULL);
if (ret != EFI_SUCCESS) {
tcg2_uninit();
goto fail;
}
ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
efi_tcg2_notify_exit_boot_services, NULL,
NULL, &event);
if (ret != EFI_SUCCESS) {
tcg2_uninit();
goto fail;
}
return ret;
fail:
log_err("Cannot install EFI_TCG2_PROTOCOL\n");
return ret;
}