Re: [PATCH v11 06/14] HP BIOSCFG driver - passwdobj-attributes
From: thomas
Date: Sun Apr 23 2023 - 05:08:07 EST
On 2023-04-20 11:54:46-0500, Jorge Lopez wrote:
> ---
> .../x86/hp/hp-bioscfg/passwdobj-attributes.c | 669 ++++++++++++++++++
> 1 file changed, 669 insertions(+)
> create mode 100644 drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c
>
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c
> new file mode 100644
> index 000000000000..c03b3a71e9c4
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c
> @@ -0,0 +1,669 @@
> +// 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"
> +#include <asm-generic/posix_types.h>
> +
> +GET_INSTANCE_ID(password);
> +/*
> + * Clear all passwords copied to memory for a particular
> + * authentication instance
> + */
> +int clear_passwords(const int instance)
> +{
> + if (!bioscfg_drv.password_data[instance].is_enabled)
> + return 0;
> +
> + memset(bioscfg_drv.password_data[instance].current_password,
> + 0, sizeof(bioscfg_drv.password_data[instance].current_password));
> + memset(bioscfg_drv.password_data[instance].new_password,
> + 0, sizeof(bioscfg_drv.password_data[instance].new_password));
> +
> + return 0;
> +}
> +
> +/*
> + * Clear all credentials copied to memory for both Power-ON and Setup
> + * BIOS instances
> + */
> +int clear_all_credentials(void)
> +{
> + int instance;
> +
> + /* clear all passwords */
> + for (instance = 0; instance < bioscfg_drv.password_instances_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 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) == 0)
> + return instance;
> + }
> + return -EINVAL;
> +}
> +
> +int validate_password_input(int instance_id, const char *buf)
> +{
> + int length;
> +
> + length = strlen(buf);
> + if (buf[length-1] == '\n')
> + length--;
> +
> + if (length > MAX_PASSWD_SIZE)
> + return INVALID_BIOS_AUTH;
> +
> + if (bioscfg_drv.password_data[instance_id].min_password_length > length ||
> + bioscfg_drv.password_data[instance_id].max_password_length < length)
> + return INVALID_BIOS_AUTH;
> + return SUCCESS;
> +}
> +
> +int password_is_set(const char *name)
bool is_password_set(const char *name)
> +{
> + int id;
> +
> + id = get_password_instance_for_type(name);
> + if (id < 0)
> + return 0;
> +
> + return bioscfg_drv.password_data[id].is_enabled;
> +}
> +
> +ATTRIBUTE_N_PROPERTY_SHOW(is_enabled, password);
> +static struct kobj_attribute password_is_password_set = __ATTR_RO(is_enabled);
> +
> +static ssize_t current_password_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *buf, size_t count)
> +{
> + char *p, *buf_cp;
> + int id, ret = 0;
> +
> + buf_cp = kstrdup(buf, GFP_KERNEL);
> + if (!buf_cp) {
> + ret = -ENOMEM;
> + goto exit_password;
> + }
> +
> + p = memchr(buf_cp, '\n', count);
> +
> + if (p != NULL)
> + *p = '\0';
This will also accept input like "foo\nbar" and truncate away the "bar".
For something like a password it seems errorprone to try to munge the
value.
> +
> + id = get_password_instance_id(kobj);
> +
> + if (id >= 0)
> + ret = validate_password_input(id, buf_cp);
> +
> + if (!ret) {
> + strscpy(bioscfg_drv.password_data[id].current_password,
> + buf_cp,
> + sizeof(bioscfg_drv.password_data[id].current_password));
> + /*
> + * set pending reboot flag depending on
> + * "RequiresPhysicalPresence" value
> + */
> + if (bioscfg_drv.password_data[id].common.requires_physical_presence)
> + bioscfg_drv.pending_reboot = true;
Just setting this to true does not emit the necessary KOBJ_CHANGE event
on the class dev kobj which is necessary for userspace to be able to
react.
> + }
> +
> +exit_password:
> + kfree(buf_cp);
> + return ret ? ret : count;
> +}
> +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)
> +{
> + char *p, *buf_cp = NULL;
> + int id = 0;
> + int ret = -EIO;
> +
> + buf_cp = kstrdup(buf, GFP_KERNEL);
> + if (!buf_cp) {
> + ret = -ENOMEM;
> + goto exit_password;
> + }
> +
> + p = memchr(buf_cp, '\n', count);
> +
> + if (p != NULL)
> + *p = '\0';
Same as above.
> +
> + id = get_password_instance_id(kobj);
> +
> + if (id >= 0)
> + ret = validate_password_input(id, buf_cp);
> +
> + if (!ret)
> + strscpy(bioscfg_drv.password_data[id].new_password,
> + buf_cp,
> + sizeof(bioscfg_drv.password_data[id].new_password));
> +
> + if (!ret)
> + ret = hp_set_attribute(kobj->name, buf_cp);
> +
> +exit_password:
> + /*
> + * Regardless of the results both new and current passwords
> + * will be set to zero and avoid security issues
> + */
> + clear_passwords(id);
> +
> + kfree(buf_cp);
> + return ret ? ret : count;
> +}
> +
> +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) == 0)
> + return sysfs_emit(buf, "%s\n", BIOS_ADMIN);
> +
> + if (strcmp(kobj->name, POWER_ON_PASSWD) == 0)
> + 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);
> +
> +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
> + char *buf)
> +{
> + return sysfs_emit(buf, "password\n");
> +}
> +static struct kobj_attribute password_type = __ATTR_RO(type);
> +
> +ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name, password);
> +static struct kobj_attribute password_display_name =
> + __ATTR_RO(display_name);
> +
> +ATTRIBUTE_S_COMMON_PROPERTY_SHOW(display_name_language_code, password);
> +static struct kobj_attribute password_display_langcode =
> + __ATTR_RO(display_name_language_code);
> +
> +ATTRIBUTE_N_COMMON_PROPERTY_SHOW(prerequisites_size, password);
> +static struct kobj_attribute password_prerequisites_size_val =
> + __ATTR_RO(prerequisites_size);
> +
> +ATTRIBUTE_V_COMMON_PROPERTY_SHOW(prerequisites, password);
> +static struct kobj_attribute password_prerequisites_val =
> + __ATTR_RO(prerequisites);
> +
> +ATTRIBUTE_N_PROPERTY_SHOW(encodings_size, password);
> +static struct kobj_attribute password_encodings_size_val =
> + __ATTR_RO(encodings_size);
As before, these size attribute are fairly pointless for userspace as
they can't be relied on.
> +
> +ATTRIBUTE_VALUES_PROPERTY_SHOW(encodings, password);
> +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_type.attr,
> + &password_display_name.attr,
> + &password_display_langcode.attr,
> + &password_prerequisites_size_val.attr,
> + &password_prerequisites_val.attr,
> + &password_encodings_val.attr,
> + &password_encodings_size_val.attr,
> + NULL
> +};
Many of these attributes are not documented.
> +
> +static const struct attribute_group bios_password_attr_group = {
> + .attrs = password_attrs
> +};
> +
> +static const struct attribute_group system_password_attr_group = {
> + .attrs = password_attrs
> +};
These groups are the same, are both needed?
> +
> +int alloc_password_data(void)
> +{
> + int ret = 0;
> +
> + bioscfg_drv.password_instances_count = get_instance_count(HP_WMI_BIOS_PASSWORD_GUID);
> + bioscfg_drv.password_data = kcalloc(bioscfg_drv.password_instances_count,
> + sizeof(struct password_data), GFP_KERNEL);
sizeof(bioscfg_drv.password_data)
> + if (!bioscfg_drv.password_data) {
> + bioscfg_drv.password_instances_count = 0;
> + ret = -ENOMEM;
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * 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 populate_password_package_data(union acpi_object *password_obj, int instance_id,
> + struct kobject *attr_name_kobj)
> +{
> + bioscfg_drv.password_data[instance_id].attr_name_kobj = attr_name_kobj;
> +
> + populate_password_elements_from_package(password_obj,
> + password_obj->package.count,
> + instance_id);
> +
> + if (strcmp(attr_name_kobj->name, "Setup Password") == 0) {
SETUP_PASSWD
> + /* Save system authentication instance for easy access */
> + return sysfs_create_group(attr_name_kobj, &bios_password_attr_group);
> + }
> +
> + return sysfs_create_group(attr_name_kobj, &system_password_attr_group);
> +}
> +
> +/* 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
> +};
> +
> +
> +int 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 = 0;
> + u32 size = 0;
> + u32 int_value;
> + int elem = 0;
> + int reqs;
> + int eloc;
> + int pos_values;
> +
> +
> + if (!password_obj)
> + return -EINVAL;
> +
> + strscpy(bioscfg_drv.password_data[instance_id].common.display_name_language_code,
> + LANG_CODE_STR,
> + sizeof(bioscfg_drv.password_data[instance_id].common.display_name_language_code));
> +
> + for (elem = 1, eloc = 1; elem < password_obj_count; elem++, eloc++) {
> +
> + /* ONLY look at the first PASSWORD_ELEM_CNT elements */
> + if (eloc == PASSWORD_ELEM_CNT)
> + goto exit_package;
> +
> + switch (password_obj[elem].type) {
> + case ACPI_TYPE_STRING:
> +
> + if (PREREQUISITES != elem && PSWD_ENCODINGS != elem) {
> + ret = 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);
> + return -EIO;
> + }
> +
> + /* Assign appropriate element value to corresponding field*/
> + switch (eloc) {
> + case VALUE:
> + break;
> + case PATH:
> + strscpy(bioscfg_drv.password_data[instance_id].common.path, str_value,
> + sizeof(bioscfg_drv.password_data[instance_id].common.path));
> + break;
> + case IS_READONLY:
> + bioscfg_drv.password_data[instance_id].common.is_readonly = int_value;
> + break;
> + case DISPLAY_IN_UI:
> + bioscfg_drv.password_data[instance_id].common.display_in_ui = int_value;
> + break;
> + case REQUIRES_PHYSICAL_PRESENCE:
> + bioscfg_drv.password_data[instance_id].common.requires_physical_presence = int_value;
> + break;
> + case SEQUENCE:
> + bioscfg_drv.password_data[instance_id].common.sequence = int_value;
> + break;
> + case PREREQUISITES_SIZE:
> + bioscfg_drv.password_data[instance_id].common.prerequisites_size = int_value;
> + if (int_value > MAX_PREREQUISITES_SIZE)
> + pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> + /*
> + * This HACK 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 = bioscfg_drv.password_data[instance_id].common.prerequisites_size;
> +
> + for (reqs = 0; reqs < size; reqs++) {
> + ret = convert_hexstr_to_str(password_obj[elem + reqs].string.pointer,
> + password_obj[elem + reqs].string.length,
> + &str_value, &value_len);
> +
> + if (ret)
> + break;
> +
> + strscpy(bioscfg_drv.password_data[instance_id].common.prerequisites[reqs],
> + str_value,
> + sizeof(bioscfg_drv.password_data[instance_id].common.prerequisites[reqs]));
> +
> + kfree(str_value);
> + }
> + break;
> +
> + case SECURITY_LEVEL:
> + bioscfg_drv.password_data[instance_id].common.security_level = int_value;
> + break;
> +
> + case PSWD_MIN_LENGTH:
> + bioscfg_drv.password_data[instance_id].min_password_length = int_value;
> + break;
> + case PSWD_MAX_LENGTH:
> + bioscfg_drv.password_data[instance_id].max_password_length = int_value;
> + break;
> + case PSWD_SIZE:
> + bioscfg_drv.password_data[instance_id].encodings_size = int_value;
> + 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");
> +
> + /*
> + * This HACK 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 = bioscfg_drv.password_data[instance_id].encodings_size;
> +
> + for (pos_values = 0; pos_values < size && pos_values < MAX_ENCODINGS_SIZE; pos_values++) {
> + ret = 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(bioscfg_drv.password_data[instance_id].encodings[pos_values],
> + str_value,
> + sizeof(bioscfg_drv.password_data[instance_id].encodings[pos_values]));
> + kfree(str_value);
> + }
> + break;
> + case PSWD_IS_SET:
> + bioscfg_drv.password_data[instance_id].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);
> + }
> +
> +exit_package:
> + kfree(str_value);
> + return 0;
> +}
> +
> +/*
> + * 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 populate_password_buffer_data(u8 *buffer_ptr, u32 *buffer_size, int instance_id,
> + struct kobject *attr_name_kobj)
> +{
> + bioscfg_drv.password_data[instance_id].attr_name_kobj = attr_name_kobj;
> +
> + /* Populate Password attributes */
> + populate_password_elements_from_buffer(buffer_ptr, buffer_size,
> + instance_id);
> + friendly_user_name_update(bioscfg_drv.password_data[instance_id].common.path,
> + attr_name_kobj->name,
> + bioscfg_drv.password_data[instance_id].common.display_name,
> + sizeof(bioscfg_drv.password_data[instance_id].common.display_name));
> + if (strcmp(attr_name_kobj->name, "Setup Password") == 0)
> + return sysfs_create_group(attr_name_kobj, &bios_password_attr_group);
> +
> + return sysfs_create_group(attr_name_kobj, &system_password_attr_group);
> +}
> +
> +int populate_password_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
> + int instance_id)
> +{
> + int ret;
> + char *dst = NULL;
> + int elem;
> + int reqs;
> + int integer;
> + int size = 0;
> + int values;
> + int dst_size = *buffer_size / sizeof(u16);
> +
> + dst = kcalloc(dst_size, sizeof(char), GFP_KERNEL);
> + if (!dst)
> + return -ENOMEM;
> +
> + elem = 0;
> + strscpy(bioscfg_drv.password_data[instance_id].common.display_name_language_code,
> + LANG_CODE_STR,
> + sizeof(bioscfg_drv.password_data[instance_id].common.display_name_language_code));
> +
> + for (elem = 1; elem < 3; elem++) {
> +
> + ret = get_string_from_buffer(&buffer_ptr, buffer_size, dst, dst_size);
> + if (ret < 0)
> + continue;
> +
> + switch (elem) {
> + case VALUE:
> + strscpy(bioscfg_drv.password_data[instance_id].current_password,
> + dst, sizeof(bioscfg_drv.password_data[instance_id].current_password));
> + break;
> + case PATH:
> + strscpy(bioscfg_drv.password_data[instance_id].common.path, dst,
> + sizeof(bioscfg_drv.password_data[instance_id].common.path));
> + break;
> + default:
> + pr_warn("Invalid element: %d found in Password attribute or data may be malformed\n", elem);
> + break;
> + }
> + }
> +
> + for (elem = 3; elem < PASSWORD_ELEM_CNT; elem++) {
> +
> + if (elem != PREREQUISITES && elem != PSWD_ENCODINGS) {
> + ret = get_integer_from_buffer((int **)&buffer_ptr, buffer_size, (int *)&integer);
> + if (ret)
> + continue;
> + }
> +
> + switch (elem) {
> + case IS_READONLY:
> + bioscfg_drv.password_data[instance_id].common.is_readonly = integer;
> + break;
> + case DISPLAY_IN_UI:
> + bioscfg_drv.password_data[instance_id].common.display_in_ui = integer;
> + break;
> + case REQUIRES_PHYSICAL_PRESENCE:
> + bioscfg_drv.password_data[instance_id].common.requires_physical_presence = integer;
> + break;
> + case SEQUENCE:
> + bioscfg_drv.password_data[instance_id].common.sequence = integer;
> + break;
> + case PREREQUISITES_SIZE:
> + bioscfg_drv.password_data[instance_id].common.prerequisites_size = integer;
> + if (integer > MAX_PREREQUISITES_SIZE)
> + pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> +
> + // PREREQUISITES:
> + elem++;
> + size = bioscfg_drv.password_data[instance_id].common.prerequisites_size;
> + for (reqs = 0; reqs < size && reqs > MAX_PREREQUISITES_SIZE; reqs++) {
> + ret = get_string_from_buffer(&buffer_ptr, buffer_size, dst, dst_size);
> + if (ret < 0)
> + continue;
> +
> + strscpy(bioscfg_drv.password_data[instance_id].common.prerequisites[reqs],
> + dst,
> + sizeof(bioscfg_drv.password_data[instance_id].common.prerequisites[reqs]));
> + }
> + break;
> + case SECURITY_LEVEL:
> + bioscfg_drv.password_data[instance_id].common.security_level = integer;
> + break;
> +
> + case PSWD_MIN_LENGTH:
> + bioscfg_drv.password_data[instance_id].min_password_length = integer;
> + break;
> + case PSWD_MAX_LENGTH:
> + bioscfg_drv.password_data[instance_id].max_password_length = integer;
> + break;
> + case PSWD_SIZE:
> + bioscfg_drv.password_data[instance_id].encodings_size = integer;
> + if (integer > MAX_ENCODINGS_SIZE)
> + pr_warn("Password Encoding size value exceeded the maximum number of elements supported or data may be malformed\n");
> +
> + // PSWD_ENCODINGS:
> + elem++;
> + size = bioscfg_drv.password_data[instance_id].encodings_size;
> + for (values = 0; values < size && values < MAX_ENCODINGS_SIZE; values++) {
> + ret = get_string_from_buffer(&buffer_ptr, buffer_size, dst, dst_size);
> + if (ret < 0)
> + continue;
> +
> + strscpy(bioscfg_drv.password_data[instance_id].encodings[values],
> + dst,
> + sizeof(bioscfg_drv.password_data[instance_id].encodings[values]));
> +
> + }
> + break;
> + case PSWD_IS_SET:
> + bioscfg_drv.password_data[instance_id].is_enabled = integer;
> + break;
> + default:
> + pr_warn("Invalid element: %d found in Password attribute or data may be malformed\n", elem);
> + break;
> + }
> + }
> + kfree(dst);
> + return 0;
> +}
> +
> +/*
> + * exit_password_attributes() - Clear all attribute data
> + *
> + * Clears all data allocated for this group of attributes
> + */
> +void 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) {
> + if (strcmp(attr_name_kobj->name, SETUP_PASSWD) == 0)
> + sysfs_remove_group(attr_name_kobj,
> + &bios_password_attr_group);
> + else
> + sysfs_remove_group(attr_name_kobj,
> + &system_password_attr_group);
> + }
> + }
> + bioscfg_drv.password_instances_count = 0;
> + kfree(bioscfg_drv.password_data);
> + bioscfg_drv.password_data = NULL;
> +}
> --
> 2.34.1
>