linux/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Functions corresponding to password object type attributes under
 * BIOS PASSWORD for use with hp-bioscfg driver.
 *
 * Copyright (c) 2022 HP Development Company, L.P.
 */

#include "bioscfg.h"

GET_INSTANCE_ID(password);
/*
 * Clear all passwords copied to memory for a particular
 * authentication instance
 */
static int clear_passwords(const int instance)
{
	struct password_data *password_data = &bioscfg_drv.password_data[instance];

	if (!password_data->is_enabled)
		return 0;

	memset(password_data->current_password,
	       0, sizeof(password_data->current_password));
	memset(password_data->new_password,
	       0, sizeof(password_data->new_password));

	return 0;
}

/*
 * Clear all credentials copied to memory for both Power-ON and Setup
 * BIOS instances
 */
int hp_clear_all_credentials(void)
{
	int count = bioscfg_drv.password_instances_count;
	int instance;

	/* clear all passwords */
	for (instance = 0; instance < count; instance++)
		clear_passwords(instance);

	/* clear auth_token */
	kfree(bioscfg_drv.spm_data.auth_token);
	bioscfg_drv.spm_data.auth_token = NULL;

	return 0;
}

int hp_get_password_instance_for_type(const char *name)
{
	int count = bioscfg_drv.password_instances_count;
	int instance;

	for (instance = 0; instance < count; instance++)
		if (!strcmp(bioscfg_drv.password_data[instance].common.display_name, name))
			return instance;

	return -EINVAL;
}

static int validate_password_input(int instance_id, const char *buf)
{
	int length;
	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];

	length = strlen(buf);
	if (buf[length - 1] == '\n')
		length--;

	if (length > MAX_PASSWD_SIZE)
		return INVALID_BIOS_AUTH;

	if (password_data->min_password_length > length ||
	    password_data->max_password_length < length)
		return INVALID_BIOS_AUTH;
	return SUCCESS;
}

ATTRIBUTE_N_PROPERTY_SHOW(is_enabled, password);
static struct kobj_attribute password_is_password_set = __ATTR_RO(is_enabled);

static int store_password_instance(struct kobject *kobj, const char *buf,
				   size_t count, bool is_current)
{
	char *buf_cp;
	int id, ret = 0;

	buf_cp = kstrdup(buf, GFP_KERNEL);
	if (!buf_cp)
		return -ENOMEM;

	ret = hp_enforce_single_line_input(buf_cp, count);
	if (!ret) {
		id = get_password_instance_id(kobj);

		if (id >= 0)
			ret = validate_password_input(id, buf_cp);
	}

	if (!ret) {
		if (is_current)
			strscpy(bioscfg_drv.password_data[id].current_password, buf_cp);
		else
			strscpy(bioscfg_drv.password_data[id].new_password, buf_cp);
	}

	kfree(buf_cp);
	return ret < 0 ? ret : count;
}

static ssize_t current_password_store(struct kobject *kobj,
				      struct kobj_attribute *attr,
				      const char *buf, size_t count)
{
	return store_password_instance(kobj, buf, count, true);
}

static struct kobj_attribute password_current_password = __ATTR_WO(current_password);

static ssize_t new_password_store(struct kobject *kobj,
				  struct kobj_attribute *attr,
				  const char *buf, size_t count)
{
	return store_password_instance(kobj, buf, count, true);
}

static struct kobj_attribute password_new_password = __ATTR_WO(new_password);

ATTRIBUTE_N_PROPERTY_SHOW(min_password_length, password);
static struct kobj_attribute password_min_password_length = __ATTR_RO(min_password_length);

ATTRIBUTE_N_PROPERTY_SHOW(max_password_length, password);
static struct kobj_attribute password_max_password_length = __ATTR_RO(max_password_length);

static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	if (!strcmp(kobj->name, SETUP_PASSWD))
		return sysfs_emit(buf, "%s\n", BIOS_ADMIN);

	if (!strcmp(kobj->name, POWER_ON_PASSWD))
		return sysfs_emit(buf, "%s\n", POWER_ON);

	return -EIO;
}

static struct kobj_attribute password_role = __ATTR_RO(role);

static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
			      char *buf)
{
	int i = get_password_instance_id(kobj);

	if (i < 0)
		return i;

	if (bioscfg_drv.password_data[i].mechanism != PASSWORD)
		return -EINVAL;

	return sysfs_emit(buf, "%s\n", PASSWD_MECHANISM_TYPES);
}

static struct kobj_attribute password_mechanism = __ATTR_RO(mechanism);

ATTRIBUTE_VALUES_PROPERTY_SHOW(encodings, password, SEMICOLON_SEP);
static struct kobj_attribute password_encodings_val = __ATTR_RO(encodings);

static struct attribute *password_attrs[] = {
	&password_is_password_set.attr,
	&password_min_password_length.attr,
	&password_max_password_length.attr,
	&password_current_password.attr,
	&password_new_password.attr,
	&password_role.attr,
	&password_mechanism.attr,
	&password_encodings_val.attr,
	NULL
};

static const struct attribute_group password_attr_group = {
	.attrs = password_attrs
};

int hp_alloc_password_data(void)
{
	bioscfg_drv.password_instances_count = hp_get_instance_count(HP_WMI_BIOS_PASSWORD_GUID);
	bioscfg_drv.password_data = kcalloc(bioscfg_drv.password_instances_count,
					    sizeof(*bioscfg_drv.password_data), GFP_KERNEL);
	if (!bioscfg_drv.password_data) {
		bioscfg_drv.password_instances_count = 0;
		return -ENOMEM;
	}

	return 0;
}

/* Expected Values types associated with each element */
static const acpi_object_type expected_password_types[] = {
	[NAME] = ACPI_TYPE_STRING,
	[VALUE] = ACPI_TYPE_STRING,
	[PATH] = ACPI_TYPE_STRING,
	[IS_READONLY] = ACPI_TYPE_INTEGER,
	[DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
	[REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
	[SEQUENCE] = ACPI_TYPE_INTEGER,
	[PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
	[PREREQUISITES] = ACPI_TYPE_STRING,
	[SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
	[PSWD_MIN_LENGTH] = ACPI_TYPE_INTEGER,
	[PSWD_MAX_LENGTH] = ACPI_TYPE_INTEGER,
	[PSWD_SIZE] = ACPI_TYPE_INTEGER,
	[PSWD_ENCODINGS] = ACPI_TYPE_STRING,
	[PSWD_IS_SET] = ACPI_TYPE_INTEGER,
};

static int hp_populate_password_elements_from_package(union acpi_object *password_obj,
						      int password_obj_count,
						      int instance_id)
{
	char *str_value = NULL;
	int value_len;
	int ret;
	u32 size;
	u32 int_value = 0;
	int elem;
	int reqs;
	int eloc;
	int pos_values;
	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];

	if (!password_obj)
		return -EINVAL;

	for (elem = 1, eloc = 1; elem < password_obj_count; elem++, eloc++) {
		/* ONLY look at the first PASSWORD_ELEM_CNT elements */
		if (eloc == PSWD_ELEM_CNT)
			goto exit_package;

		switch (password_obj[elem].type) {
		case ACPI_TYPE_STRING:
			if (PREREQUISITES != elem && PSWD_ENCODINGS != elem) {
				ret = hp_convert_hexstr_to_str(password_obj[elem].string.pointer,
							       password_obj[elem].string.length,
							       &str_value, &value_len);
				if (ret)
					continue;
			}
			break;
		case ACPI_TYPE_INTEGER:
			int_value = (u32)password_obj[elem].integer.value;
			break;
		default:
			pr_warn("Unsupported object type [%d]\n", password_obj[elem].type);
			continue;
		}

		/* Check that both expected and read object type match */
		if (expected_password_types[eloc] != password_obj[elem].type) {
			pr_err("Error expected type %d for elem %d, but got type %d instead\n",
			       expected_password_types[eloc], elem, password_obj[elem].type);
			kfree(str_value);
			return -EIO;
		}

		/* Assign appropriate element value to corresponding field*/
		switch (eloc) {
		case VALUE:
			break;
		case PATH:
			strscpy(password_data->common.path, str_value);
			break;
		case IS_READONLY:
			password_data->common.is_readonly = int_value;
			break;
		case DISPLAY_IN_UI:
			password_data->common.display_in_ui = int_value;
			break;
		case REQUIRES_PHYSICAL_PRESENCE:
			password_data->common.requires_physical_presence = int_value;
			break;
		case SEQUENCE:
			password_data->common.sequence = int_value;
			break;
		case PREREQUISITES_SIZE:
			if (int_value > MAX_PREREQUISITES_SIZE) {
				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
				int_value = MAX_PREREQUISITES_SIZE;
			}
			password_data->common.prerequisites_size = int_value;

			/* This step is needed to keep the expected
			 * element list pointing to the right obj[elem].type
			 * when the size is zero. PREREQUISITES
			 * object is omitted by BIOS when the size is
			 * zero.
			 */
			if (int_value == 0)
				eloc++;
			break;
		case PREREQUISITES:
			size = min_t(u32, password_data->common.prerequisites_size,
				     MAX_PREREQUISITES_SIZE);

			for (reqs = 0; reqs < size; reqs++) {
				ret = hp_convert_hexstr_to_str(password_obj[elem + reqs].string.pointer,
							       password_obj[elem + reqs].string.length,
							       &str_value, &value_len);

				if (ret)
					break;

				strscpy(password_data->common.prerequisites[reqs], str_value);

				kfree(str_value);
				str_value = NULL;

			}
			break;
		case SECURITY_LEVEL:
			password_data->common.security_level = int_value;
			break;
		case PSWD_MIN_LENGTH:
			password_data->min_password_length = int_value;
			break;
		case PSWD_MAX_LENGTH:
			password_data->max_password_length = int_value;
			break;
		case PSWD_SIZE:

			if (int_value > MAX_ENCODINGS_SIZE) {
				pr_warn("Password Encoding size value exceeded the maximum number of elements supported or data may be malformed\n");
				int_value = MAX_ENCODINGS_SIZE;
			}
			password_data->encodings_size = int_value;

			/* This step is needed to keep the expected
			 * element list pointing to the right obj[elem].type
			 * when the size is zero. PSWD_ENCODINGS
			 * object is omitted by BIOS when the size is
			 * zero.
			 */
			if (int_value == 0)
				eloc++;
			break;
		case PSWD_ENCODINGS:
			size = min_t(u32, password_data->encodings_size, MAX_ENCODINGS_SIZE);
			for (pos_values = 0; pos_values < size; pos_values++) {
				ret = hp_convert_hexstr_to_str(password_obj[elem + pos_values].string.pointer,
							       password_obj[elem + pos_values].string.length,
							       &str_value, &value_len);
				if (ret)
					break;

				strscpy(password_data->encodings[pos_values], str_value);
				kfree(str_value);
				str_value = NULL;

			}
			break;
		case PSWD_IS_SET:
			password_data->is_enabled = int_value;
			break;
		default:
			pr_warn("Invalid element: %d found in Password attribute or data may be malformed\n", elem);
			break;
		}

		kfree(str_value);
		str_value = NULL;
	}

exit_package:
	kfree(str_value);
	return 0;
}

/**
 * hp_populate_password_package_data()
 *	Populate all properties for an instance under password attribute
 *
 * @password_obj: ACPI object with password data
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_password_package_data(union acpi_object *password_obj, int instance_id,
				      struct kobject *attr_name_kobj)
{
	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];

	password_data->attr_name_kobj = attr_name_kobj;

	hp_populate_password_elements_from_package(password_obj,
						   password_obj->package.count,
						   instance_id);

	hp_friendly_user_name_update(password_data->common.path,
				     attr_name_kobj->name,
				     password_data->common.display_name,
				     sizeof(password_data->common.display_name));

	if (!strcmp(attr_name_kobj->name, SETUP_PASSWD))
		return sysfs_create_group(attr_name_kobj, &password_attr_group);

	return sysfs_create_group(attr_name_kobj, &password_attr_group);
}

static int hp_populate_password_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
						     int instance_id)
{
	int values;
	int isreadonly;
	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
	int ret = 0;

	/*
	 * Only data relevant to this driver and its functionality is
	 * read. BIOS defines the order in which each * element is
	 * read. Element 0 data is not relevant to this
	 * driver hence it is ignored. For clarity, all element names
	 * (DISPLAY_IN_UI) which defines the order in which is read
	 * and the name matches the variable where the data is stored.
	 *
	 * In earlier implementation, reported errors were ignored
	 * causing the data to remain uninitialized. It is not
	 * possible to determine if data read from BIOS is valid or
	 * not. It is for this reason functions may return a error
	 * without validating the data itself.
	 */

	// VALUE:
	ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, password_data->current_password,
					sizeof(password_data->current_password));
	if (ret < 0)
		goto buffer_exit;

	// COMMON:
	ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size,
					     &password_data->common);
	if (ret < 0)
		goto buffer_exit;

	// PSWD_MIN_LENGTH:
	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
					 &password_data->min_password_length);
	if (ret < 0)
		goto buffer_exit;

	// PSWD_MAX_LENGTH:
	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
					 &password_data->max_password_length);
	if (ret < 0)
		goto buffer_exit;

	// PSWD_SIZE:
	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
					 &password_data->encodings_size);
	if (ret < 0)
		goto buffer_exit;

	if (password_data->encodings_size > MAX_ENCODINGS_SIZE) {
		/* Report a message and limit possible values size to maximum value */
		pr_warn("Password Encoding size value exceeded the maximum number of elements supported or data may be malformed\n");
		password_data->encodings_size = MAX_ENCODINGS_SIZE;
	}

	// PSWD_ENCODINGS:
	for (values = 0; values < password_data->encodings_size; values++) {
		ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size,
						password_data->encodings[values],
						sizeof(password_data->encodings[values]));
		if (ret < 0)
			break;
	}

	// PSWD_IS_SET:
	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size, &isreadonly);
	if (ret < 0)
		goto buffer_exit;

	password_data->is_enabled = isreadonly ? true : false;

buffer_exit:
	return ret;
}

/**
 * hp_populate_password_buffer_data()
 * Populate all properties for an instance under password object attribute
 *
 * @buffer_ptr: Buffer pointer
 * @buffer_size: Buffer size
 * @instance_id: The instance to enumerate
 * @attr_name_kobj: The parent kernel object
 */
int hp_populate_password_buffer_data(u8 *buffer_ptr, u32 *buffer_size, int instance_id,
				     struct kobject *attr_name_kobj)
{
	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
	int ret = 0;

	password_data->attr_name_kobj = attr_name_kobj;

	/* Populate Password attributes */
	ret = hp_populate_password_elements_from_buffer(buffer_ptr, buffer_size,
							instance_id);
	if (ret < 0)
		return ret;

	hp_friendly_user_name_update(password_data->common.path,
				     attr_name_kobj->name,
				     password_data->common.display_name,
				     sizeof(password_data->common.display_name));
	if (!strcmp(attr_name_kobj->name, SETUP_PASSWD))
		return sysfs_create_group(attr_name_kobj, &password_attr_group);

	return sysfs_create_group(attr_name_kobj, &password_attr_group);
}

/**
 * hp_exit_password_attributes() - Clear all attribute data
 *
 * Clears all data allocated for this group of attributes
 */
void hp_exit_password_attributes(void)
{
	int instance_id;

	for (instance_id = 0; instance_id < bioscfg_drv.password_instances_count;
	     instance_id++) {
		struct kobject *attr_name_kobj =
			bioscfg_drv.password_data[instance_id].attr_name_kobj;

		if (attr_name_kobj)
			sysfs_remove_group(attr_name_kobj,
					   &password_attr_group);
	}
	bioscfg_drv.password_instances_count = 0;
	kfree(bioscfg_drv.password_data);
	bioscfg_drv.password_data = NULL;
}