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Date:   Sun, 23 Apr 2023 11:07:54 +0200
From:   thomas@t-8ch.de
To:     Jorge Lopez <jorgealtxwork@gmail.com>
Cc:     hdegoede@redhat.com, platform-driver-x86@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v11 06/14] HP BIOSCFG driver - passwdobj-attributes
Message-ID: <016a9a6a-cff1-444d-b96a-63eded1ac58a@t-8ch.de>
References: <20230420165454.9517-1-jorge.lopez2@hp.com>
 <20230420165454.9517-7-jorge.lopez2@hp.com>
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In-Reply-To: <20230420165454.9517-7-jorge.lopez2@hp.com>
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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
>