// 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 = kzalloc_objs(*bioscfg_drv.password_data,
                                                 bioscfg_drv.password_instances_count);
        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++) {
                                if (elem + reqs >= password_obj_count) {
                                        pr_err("Error elem-objects package is too small\n");
                                        return -EINVAL;
                                }

                                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;
}