[v4,2/6] Introduction of HP-BIOSCFG driver

Commit Message

Jorge Lopez Oct. 20, 2022, 8:10 p.m. UTC

The purpose for this patch is submit HP BIOSCFG driver to be list of
HP Linux kernel drivers.  The driver include a total of 12 files
broken in several patches.  This is set 1 of 4.

HP BIOS Configuration driver purpose is to provide a driver supporting
the latest sysfs class firmware attributes framework allowing the user
to change BIOS settings and security solutions on HP Inc.’s commercial
notebooks.

Many features of HP Commercial PC’s can be managed using Windows
Management Instrumentation (WMI). WMI is an implementation of Web-Based
Enterprise Management (WBEM) that provides a standards-based interface
for changing and monitoring system settings.  HP BISOCFG driver provides
a native Linux solution and the exposed features facilitates the
migration to Linux environments.

The Linux security features to be provided in hp-bioscfg driver enables
managing the BIOS settings and security solutions via sysfs, a virtual
filesystem that can be used by user-mode applications.   The new
documentation cover features such Secure Platform Management, Sure
Admin, and Sure Start.  Each section provides security feature
description and identifies sysfs directories and files exposed by
the driver.

Many HP Commercial PC’s include a feature called Secure Platform
Management (SPM), which replaces older password-based BIOS settings
management with public key cryptography. PC secure product management
begins when a target system is provisioned with cryptographic keys
that are used to ensure the integrity of communications between system
management utilities and the BIOS.

HP Commercial PC’s have several BIOS settings that control its behaviour
and capabilities, many of which are related to security. To prevent
unauthorized changes to these settings, the system can be configured
to use a Sure Admin cryptographic signature-based authorization string
that the BIOS will use to verify authorization to modify the setting.

Signed-off-by: Jorge Lopez <[e-mail]>

---
Based on the latest platform-drivers-x86.git/for-next
---
 .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
 .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
 3 files changed, 1477 insertions(+)
 create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
 create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
 create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c

Comments

Hans de Goede Nov. 8, 2022, 2:51 p.m. UTC | #1

Hi Jorge,

Review comments inline.

On 10/20/22 22:10, Jorge Lopez wrote:
> The purpose for this patch is submit HP BIOSCFG driver to be list of
> HP Linux kernel drivers.  The driver include a total of 12 files
> broken in several patches.  This is set 1 of 4.
> 
> HP BIOS Configuration driver purpose is to provide a driver supporting
> the latest sysfs class firmware attributes framework allowing the user
> to change BIOS settings and security solutions on HP Inc.’s commercial
> notebooks.
> 
> Many features of HP Commercial PC’s can be managed using Windows
> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> Enterprise Management (WBEM) that provides a standards-based interface
> for changing and monitoring system settings.  HP BISOCFG driver provides
> a native Linux solution and the exposed features facilitates the
> migration to Linux environments.
> 
> The Linux security features to be provided in hp-bioscfg driver enables
> managing the BIOS settings and security solutions via sysfs, a virtual
> filesystem that can be used by user-mode applications.   The new
> documentation cover features such Secure Platform Management, Sure
> Admin, and Sure Start.  Each section provides security feature
> description and identifies sysfs directories and files exposed by
> the driver.
> 
> Many HP Commercial PC’s include a feature called Secure Platform
> Management (SPM), which replaces older password-based BIOS settings
> management with public key cryptography. PC secure product management
> begins when a target system is provisioned with cryptographic keys
> that are used to ensure the integrity of communications between system
> management utilities and the BIOS.
> 
> HP Commercial PC’s have several BIOS settings that control its behaviour
> and capabilities, many of which are related to security. To prevent
> unauthorized changes to these settings, the system can be configured
> to use a Sure Admin cryptographic signature-based authorization string
> that the BIOS will use to verify authorization to modify the setting.
> 
> Signed-off-by: Jorge Lopez <[e-mail]>
> 
> ---
> Based on the latest platform-drivers-x86.git/for-next
> ---
>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>  3 files changed, 1477 insertions(+)
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> 
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> new file mode 100644
> index 000000000000..f0c919bf3ab0
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> @@ -0,0 +1,285 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to methods under BIOS interface GUID
> + * for use with hp-bioscfg driver.
> + *
> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> + */
> +
> +#include <linux/wmi.h>
> +#include "bioscfg.h"
> +
> +#define SET_DEFAULT_VALUES_METHOD_ID	0x02
> +#define SET_BIOS_DEFAULTS_METHOD_ID	0x03
> +#define SET_ATTRIBUTE_METHOD_ID		0x04
> +
> +/*
> + * set_attribute() - Update an attribute value
> + * @a_name: The attribute name
> + * @a_value: The attribute value
> + *
> + * Sets an attribute to new value
> + */
> +int hp_set_attribute(const char *a_name, const char *a_value)
> +{
> +	size_t security_area_size;
> +	size_t a_name_size, a_value_size;
> +	u16 *buffer = NULL;
> +	u16 *start = NULL;
> +	int  buffer_size;

You have 2 spaces between int and buffer_size here, please drop
one.


> +	int ret;
> +	int instance;
> +	char *auth_empty_value = " ";
> +
> +	mutex_lock(&bioscfg_drv.mutex);
> +	if (!bioscfg_drv.bios_attr_wdev) {
> +		ret = -ENODEV;
> +		goto out_set_attribute;
> +	}
> +
> +	instance = get_password_instance_for_type(SETUP_PASSWD);
> +	if (instance < 0)
> +		goto out_set_attribute;
> +
> +	if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> +		strncpy(bioscfg_drv.password_data[instance].current_password,
> +			auth_empty_value,
> +			sizeof(bioscfg_drv.password_data[instance].current_password));

strncpy does not guarantee 0 termination of the destination buffer,
please use strscpy.

> +
> +	a_name_size = calculate_string_buffer(a_name);
> +	a_value_size = calculate_string_buffer(a_value);
> +	security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> +	buffer_size = a_name_size + a_value_size + security_area_size;
> +
> +	buffer = kzalloc(buffer_size, GFP_KERNEL);
> +	if (!buffer) {
> +		ret = -ENOMEM;
> +		goto out_set_attribute;
> +	}
> +
> +	/* build variables to set */
> +	start = buffer;
> +	start = ascii_to_utf16_unicode(start, a_name);
> +	if (!start)
> +		goto out_set_attribute;
> +
> +	start = ascii_to_utf16_unicode(start, a_value);
> +	if (!start)
> +		goto out_set_attribute;
> +
> +	populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> +	ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> +
> +
> +out_set_attribute:
> +	kfree(buffer);
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	return ret;
> +}
> +
> +/*
> + * hp_wmi_perform_query
> + *
> + * query:	The commandtype (enum hp_wmi_commandtype)
> + * write:	The command (enum hp_wmi_command)
> + * buffer:	Buffer used as input and/or output
> + * insize:	Size of input buffer
> + * outsize:	Size of output buffer
> + *
> + * returns zero on success
> + *         an HP WMI query specific error code (which is positive)
> + *         -EINVAL if the query was not successful at all
> + *         -EINVAL if the output buffer size exceeds buffersize
> + *
> + * Note: The buffersize must at least be the maximum of the input and output
> + *       size. E.g. Battery info query is defined to have 1 byte input
> + *       and 128 byte output. The caller would do:
> + *       buffer = kzalloc(128, GFP_KERNEL);
> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> + */
> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> +{
> +	struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	struct bios_return *bios_return;
> +	union acpi_object *obj = NULL;
> +	struct bios_args *args = NULL;
> +	int mid, actual_insize, actual_outsize;
> +	size_t bios_args_size;
> +	int ret;
> +
> +	mid = encode_outsize_for_pvsz(outsize);
> +	if (WARN_ON(mid < 0))
> +		return mid;
> +
> +	actual_insize = insize;
> +	bios_args_size = struct_size(args, data, insize);
> +	args = kmalloc(bios_args_size, GFP_KERNEL);
> +	if (!args)
> +		return -ENOMEM;
> +
> +	input.length = bios_args_size;
> +	input.pointer = args;
> +
> +	args->signature = 0x55434553;
> +	args->command = command;
> +	args->commandtype = query;
> +	args->datasize = insize;
> +	memcpy(args->data, buffer, flex_array_size(args, data, insize));
> +
> +	ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> +	bioscfg_drv.last_wmi_status = ret;
> +	if (ret)
> +		goto out_free;
> +
> +	obj = output.pointer;
> +	if (!obj) {
> +		ret = -EINVAL;
> +		goto out_free;
> +	}
> +

You need to check the type of obj here before dereferencing
obj as if it is a buffer.

> +	bios_return = (struct bios_return *)obj->buffer.pointer;
> +	ret = bios_return->return_code;
> +	bioscfg_drv.last_wmi_status = ret;
> +	if (ret) {
> +		if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> +		    ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> +			pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> +		goto out_free;
> +	}
> +
> +	/* Ignore output data of zero size */
> +	if (!outsize)
> +		goto out_free;
> +
> +	actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> +	memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> +	memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> +
> +out_free:
> +	kfree(obj);
> +	kfree(args);
> +	return ret;
> +}
> +
> +/*
> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> + *
> + * @p:   Unicode buffer address
> + * @str: string to convert to unicode
> + *
> + * Returns a void pointer to the buffer containing unicode string
> + */
> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> +{
> +	int len = strlen(str);
> +	int ret;
> +
> +	/*
> +	 * Add null character when reading an empty string
> +	 */
> +	if (len == 0) {
> +		*p++ = 2;
> +		*p++ = (u8)0x00;
> +		return p;

This does not match with calculate_string_buffer() which will
return 2 for a 0 length string while you are using 4 bytes here.

I guess this may also be why you need to use " " for
auth_empty_value above, so as to avoid this bug.


> +	}
> +	*p++ = len * 2;
> +	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
> +
> +	if (ret < 0) {
> +		dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
> +		goto ascii_to_utf16_unicode_out;

You have an error here, but you don't return an error at the end of
this function.

Please for version 5 do the following:

1. Add a preparation patch which moves populate_string_buffer()
and calculate_string_buffer() from
drivers/platform/x86/dell/dell-wmi-sysman/sysman.c to
drivers/platform/x86/wmi.c

Renaming them to:

size_t wmi_utf16_str_size(const char *str);
ssize_t wmi_str_to_utf16_str(u16 *buffer, size_t buffer_len, const char *str);

(adding these prototypes to include/linux/wmi.h)

and make the dell-wmi-sysman code use these new helpers

2. Also use these new helpers in your own code instead
of your own ascii_to_utf16_unicode() function

> +	}
> +
> +	if ((ret * sizeof(u16)) > U16_MAX) {
> +		dev_err(bioscfg_drv.class_dev, "Error string too long\n");
> +		goto ascii_to_utf16_unicode_out;
> +	}
> +
> +ascii_to_utf16_unicode_out:
> +	p += len;
> +	return p;
> +}
> +
> +/*
> + * hp_wmi_set_bios_setting - Set setting's value in BIOS
> + *
> + * @input_buffer: Input buffer address
> + * @input_size:   Input buffer size
> + *
> + * Returns: Count of unicode characters written to BIOS if successful, otherwise
> + *		-ENOMEM unable to allocate memory
> + *		-EINVAL buffer not allocated or too small
> + */
> +int hp_wmi_set_bios_setting(void *input_buffer, int input_size)
> +{
> +	union acpi_object *obj;
> +	struct acpi_buffer input = {input_size, input_buffer};
> +	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> +	int ret = 0;
> +
> +	ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output);
> +
> +	obj = output.pointer;
> +	if (!obj)
> +		return -EINVAL;
> +
> +	if (obj->type != ACPI_TYPE_INTEGER)
> +		ret = -EINVAL;
> +
> +	ret = obj->integer.value;
> +
> +	kfree(obj);
> +	return ret;
> +}
> +
> +/*
> + * set_bios_defaults() - Resets BIOS defaults
> + *
> + * @deftype: the type of BIOS value reset to issue.
> + *
> + * Resets BIOS defaults
> + */
> +int set_bios_defaults(u8 deftype)
> +{
> +	return -EOPNOTSUPP;
> +}

This function is not used anywhere, please drop it.

> +
> +static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
> +{
> +	mutex_lock(&bioscfg_drv.mutex);
> +	bioscfg_drv.bios_attr_wdev = wdev;
> +	mutex_unlock(&bioscfg_drv.mutex);
> +	return 0;
> +}
> +
> +static void bios_attr_set_interface_remove(struct wmi_device *wdev)
> +{
> +	mutex_lock(&bioscfg_drv.mutex);
> +	bioscfg_drv.bios_attr_wdev = NULL;
> +	mutex_unlock(&bioscfg_drv.mutex);
> +}
> +
> +static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
> +	{ .guid_string = HP_WMI_BIOS_GUID},
> +	{ },
> +};
> +static struct wmi_driver bios_attr_set_interface_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME
> +	},
> +	.probe = bios_attr_set_interface_probe,
> +	.remove = bios_attr_set_interface_remove,
> +	.id_table = bios_attr_set_interface_id_table,
> +};
> +
> +int init_bios_attr_set_interface(void)
> +{
> +	return wmi_driver_register(&bios_attr_set_interface_driver);
> +}
> +
> +void exit_bios_attr_set_interface(void)
> +{
> +	wmi_driver_unregister(&bios_attr_set_interface_driver);
> +}
> +
> +MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> new file mode 100644
> index 000000000000..4409481f84f2
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> @@ -0,0 +1,671 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * Definitions for kernel modules using hp_bioscfg driver
> + *
> + *  Copyright (c) 2022 HP Development Company, L.P.
> + */
> +
> +#ifndef _HP_BIOSCFG_H_
> +#define _HP_BIOSCFG_H_
> +
> +#include <linux/wmi.h>
> +#include <linux/types.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/capability.h>
> +#include <linux/nls.h>
> +
> +
> +#define DRIVER_NAME	"hp-bioscfg"
> +
> +#define MAX_BUFF		512
> +#define MAX_KEY_MOD		256
> +#define MAX_PASSWD_SIZE		64
> +#define MAX_MESSAGE_SIZE        256
> +
> +#define SPM_STR_DESC	"Secure Platform Management"
> +#define SPM_STR		"SPM"
> +#define SURE_START_DESC "Sure Start"
> +#define SURE_START_STR  "Sure_Start"
> +#define SURE_ADMIN_DESC "Sure Admin"
> +#define SURE_ADMIN_STR  "Sure_Admin"
> +#define SETUP_PASSWD	"Setup Password"
> +#define POWER_ON_PASSWD	"Power-On Password"
> +
> +#define LANG_CODE_STR		"en_US.UTF-8"
> +#define SCHEDULE_POWER_ON	"Scheduled Power-On"
> +
> +/* Sure Admin Functions */
> +
> +#define UTF_PREFIX	((unsigned char *)"<utf-16/>")
> +#define BEAM_PREFIX	((unsigned char *)"<BEAM/>")
> +
> +/* mechanism - Authentication attribute */
> +
> +#define MAX_MECHANISM_TYPES 3
> +
> +enum mechanism_values {
> +	PASSWORD	= 0x00,
> +	NOT_PROVISION   = 0x00,
> +	SIGNING_KEY	= 0x01,
> +	ENDORSEMENT_KEY = 0x02
> +};
> +
> +static const char * const spm_mechanism_types[] = {
> +	"not provision",
> +	"signing-key",
> +	"endorsement-key"
> +};
> +
> +static const char * const passwd_mechanism_types[] = {
> +	"password",
> +};
> +
> +/* roles - Authentication attribute */
> +enum role_values {
> +	BIOS_ADMIN	= 0x00,
> +	POWER_ON	= 0x01,
> +	BIOS_SPM	= 0x02
> +};
> +
> +static const char * const role_type[] = {
> +	"bios-admin",
> +	"power-on",
> +	"enhanced-bios-auth"
> +};
> +
> +
> +#define HP_WMI_BIOS_GUID		"5FB7F034-2C63-45e9-BE91-3D44E2C707E4"
> +
> +#define HP_WMI_BIOS_STRING_GUID		"988D08E3-68F4-4c35-AF3E-6A1B8106F83C"
> +#define HP_WMI_BIOS_INTEGER_GUID	"8232DE3D-663D-4327-A8F4-E293ADB9BF05"
> +#define HP_WMI_BIOS_ENUMERATION_GUID	"2D114B49-2DFB-4130-B8FE-4A3C09E75133"
> +#define HP_WMI_BIOS_ORDERED_LIST_GUID	"14EA9746-CE1F-4098-A0E0-7045CB4DA745"
> +#define HP_WMI_BIOS_PASSWORD_GUID	"322F2028-0F84-4901-988E-015176049E2D"
> +#define HP_WMI_SET_BIOS_SETTING_GUID	"1F4C91EB-DC5C-460b-951D-C7CB9B4B8D5E"
> +
> +enum hp_wmi_spm_commandtype {
> +	HPWMI_SECUREPLATFORM_GET_STATE  = 0x10,
> +	HPWMI_SECUREPLATFORM_SET_KEK	= 0x11,
> +	HPWMI_SECUREPLATFORM_SET_SK	= 0x12,
> +};
> +
> +enum hp_wmi_surestart_commandtype {
> +	HPWMI_SURESTART_GET_LOG_COUNT	= 0x01,
> +	HPWMI_SURESTART_GET_LOG		= 0x02,
> +};
> +
> +enum hp_wmi_command {
> +	HPWMI_READ		= 0x01,
> +	HPWMI_WRITE		= 0x02,
> +	HPWMI_ODM		= 0x03,
> +	HPWMI_SURESTART		= 0x20006,
> +	HPWMI_GM		= 0x20008,
> +	HPWMI_SECUREPLATFORM	= 0x20010,
> +};
> +
> +struct bios_return {
> +	u32 sigpass;
> +	u32 return_code;
> +};
> +
> +enum hp_return_value {
> +	HPWMI_RET_WRONG_SIGNATURE	= 0x02,
> +	HPWMI_RET_UNKNOWN_COMMAND	= 0x03,
> +	HPWMI_RET_UNKNOWN_CMDTYPE	= 0x04,
> +	HPWMI_RET_INVALID_PARAMETERS	= 0x05,
> +};
> +
> +enum wmi_error_values {
> +	SUCCESS			= 0x00,
> +	CMD_FAILED			= 0x01,
> +	INVALID_SIGN			= 0x02,
> +	INVALID_CMD_VALUE		= 0x03,
> +	INVALID_CMD_TYPE		= 0x04,
> +	INVALID_DATA_SIZE		= 0x05,
> +	INVALID_CMD_PARAM		= 0x06,
> +	ENCRYP_CMD_REQUIRED		= 0x07,
> +	NO_SECURE_SESSION		= 0x08,
> +	SECURE_SESSION_FOUND		= 0x09,
> +	SECURE_SESSION_FAILED		= 0x0A,
> +	AUTH_FAILED			= 0x0B,
> +	INVALID_BIOS_AUTH		= 0x0E,
> +	NONCE_DID_NOT_MATCH		= 0x18,
> +	GENERIC_ERROR			= 0x1C,
> +	BIOS_ADMIN_POLICY_NOT_MET	= 0x28,
> +	BIOS_ADMIN_NOT_SET		= 0x38,
> +	P21_NO_PROVISIONED		= 0x1000,
> +	P21_PROVISION_IN_PROGRESS	= 0x1001,
> +	P21_IN_USE			= 0x1002,
> +	HEP_NOT_ACTIVE			= 0x1004,
> +	HEP_ALREADY_SET		= 0x1006,
> +	HEP_CHECK_STATE		= 0x1007
> +};
> +
> +enum spm_features {
> +	HEP_ENABLED		= 0x01,
> +	PLATFORM_RECOVERY	= 0x02,
> +	ENHANCED_BIOS_AUTH_MODE	= 0x04
> +};
> +
> +
> +/*
> + * struct bios_args buffer is dynamically allocated.  New WMI command types
> + * were introduced that exceeds 128-byte data size.  Changes to handle
> + * the data size allocation scheme were kept in hp_wmi_perform_qurey function.
> + */
> +struct bios_args {
> +	u32 signature;
> +	u32 command;
> +	u32 commandtype;
> +	u32 datasize;
> +	u8 data[];
> +};
> +
> +
> +#pragma pack(1)
> +struct secureplatform_provisioning_data {
> +	u8 state;
> +	u8 version[2];
> +	u8 reserved1;
> +	u32 features;
> +	u32 nonce;
> +	u8 reserved2[28];
> +	u8 sk_mod[MAX_KEY_MOD];
> +	u8 kek_mod[MAX_KEY_MOD];
> +};
> +
> +#pragma pack()
> +
> +
> +struct string_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 min_length;
> +	u32 max_length;
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct integer_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u32 current_value;
> +	u32 new_value;
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 lower_bound;
> +	u32 upper_bound;
> +	u32 scalar_increment;
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct enumeration_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u32 size;
> +	u8 possible_values[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct ordered_list_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_value[MAX_BUFF];
> +	u8 new_value[MAX_BUFF];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 size;
> +	u8 elements[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 type;
> +};
> +
> +struct password_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +	u8 current_password[MAX_PASSWD_SIZE];
> +	u8 new_password[MAX_PASSWD_SIZE];
> +	u8 path[MAX_BUFF];
> +	u32 is_readonly;
> +	u32 display_in_ui;
> +	u32 requires_physical_presence;
> +	u32 sequence;
> +	u32 prerequisitesize;
> +	u8 prerequisites[MAX_BUFF];
> +	u32 security_level;
> +	u32 min_password_length;
> +	u32 max_password_length;
> +	u32 encoding_size;
> +	u8 supported_encoding[MAX_BUFF];
> +	u8 display_name_language_code[MAX_BUFF];
> +	u32 is_enabled;
> +
> +	// 'bios-admin' 'power-on'
> +	u32 role;
> +
> +	//'password'
> +	u32 mechanism;
> +	u32 type;
> +};
> +
> +struct secure_platform_data {
> +	struct kobject *attr_name_kobj;
> +	u8 attribute_name[MAX_BUFF];
> +	u8 display_name[MAX_BUFF];
> +
> +	u8 *endorsement_key;
> +	u8 *signing_key;
> +
> +	u32 is_enabled;
> +	u32 mechanism;
> +	u32 type;
> +};
> +
> +struct bioscfg_priv {
> +	struct wmi_device *password_attr_wdev;
> +	struct wmi_device *bios_attr_wdev;
> +	struct kset *authentication_dir_kset;
> +	struct kset *main_dir_kset;
> +	struct device *class_dev;
> +	struct string_data *string_data;
> +	u32 string_instances_count;
> +	struct integer_data *integer_data;
> +	u32 integer_instances_count;
> +	struct enumeration_data *enumeration_data;
> +	u32 enumeration_instances_count;
> +	struct ordered_list_data *ordered_list_data;
> +	u32 ordered_list_instances_count;
> +	struct password_data *password_data;
> +	u32 password_instances_count;
> +
> +	struct kobject *sure_start_attr_kobj;
> +	struct kobject *sure_admin_attr_kobj;
> +	struct secure_platform_data spm_data;
> +
> +	int  last_wmi_status;
> +	bool pending_reboot;
> +	struct mutex mutex;
> +};
> +
> +/* global structure used by multiple WMI interfaces */
> +extern struct bioscfg_priv bioscfg_drv;
> +
> +enum hp_wmi_data_type {
> +	HPWMI_STRING_TYPE		= 0x00,
> +	HPWMI_INTEGER_TYPE		= 0x01,
> +	HPWMI_ENUMERATION_TYPE		= 0x02,
> +	HPWMI_ORDERED_LIST_TYPE		= 0x03,
> +	HPWMI_PASSWORD_TYPE		= 0x04,
> +	HPWMI_SECURE_PLATFORM_TYPE	= 0x05,
> +	HPWMI_SURE_START_TYPE		= 0x06,
> +	HPWMI_SURE_ADMIN_TYPE           = 0x07,
> +};
> +
> +enum hp_wmi_data_elements {
> +
> +	/* Common elements */
> +	NAME = 0,
> +	VALUE = 1,
> +	PATH = 2,
> +	IS_READONLY = 3,
> +	DISPLAY_IN_UI = 4,
> +	REQUIRES_PHYSICAL_PRESENCE = 5,
> +	SEQUENCE = 6,
> +	PREREQUISITE_SIZE = 7,
> +	PREREQUISITES = 8,
> +	SECURITY_LEVEL = 9,
> +
> +	/* String elements */
> +	STR_MIN_LENGTH = 10,
> +	STR_MAX_LENGTH = 11,
> +
> +	/* Integer elements */
> +	INT_LOWER_BOUND = 10,
> +	INT_UPPER_BOUND = 11,
> +	INT_SCALAR_INCREMENT = 12,
> +
> +	/* Enumeration elements */
> +	ENUM_CURRENT_VALUE = 10,
> +	ENUM_SIZE = 11,
> +	ENUM_POSSIBLE_VALUES = 12,
> +
> +	/* Ordered list elements */
> +	ORD_LIST_SIZE = 10,
> +	ORD_LIST_ELEMENTS = 11,
> +
> +	/* Password elements */
> +	PSWD_MIN_LENGTH = 10,
> +	PSWD_MAX_LENGTH = 11,
> +	PSWD_SIZE = 12,
> +	PSWD_SUPPORTED_ENCODING = 13,
> +	PSWD_IS_SET = 14
> +};
> +
> +
> +static const int hp_wmi_elements_count[] = {
> +	12,   // string
> +	13,   // integer
> +	13,   // enumeration
> +	12,   // ordered list
> +	15    // password
> +};
> +
> +#define get_instance_id(type)							\
> +static int get_##type##_instance_id(struct kobject *kobj)			\
> +{										\
> +	int i; \
> +								\
> +	for (i = 0; i <= bioscfg_drv.type##_instances_count; i++) { \
> +		if (!(strcmp(kobj->name, bioscfg_drv.type##_data[i].attribute_name))) \
> +			return i;						\
> +	}									\
> +	return -EIO;								\
> +}
> +
> +#define get_instance_id_for_attribute(type)			\
> +static int get_instance_id_for_##type(char *attr_name)	        \
> +{										\
> +	int i;									\
> +										\
> +	for (i = 0; i < bioscfg_drv.type##_instances_count; i++) {		\
> +		if (strcmp(bioscfg_drv.type##_data[i].attribute_name, attr_name) == 0)						\
> +			return i;						\
> +	}									\
> +	return -EIO;								\
> +}
> +
> +#define attribute_s_property_show(name, type)					\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].name);	\

Please use sysfs_emit instead of sprintf for this and all the other _show() functions.

> +	return 0;								\
> +}
> +/* There is no need to keep track of default and current values
> + * separately
> + */
> +#define attribute_s_default_property_show(name, type, new_name)			\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].new_name);	\
> +	return 0;								\
> +}
> +
> +#define attribute_n_default_property_show(name, type, new_name)			\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].new_name); \
> +	return 0;								\
> +}
> +
> +#define attribute_n_property_show(name, type)					\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
> +			   char *buf)						\
> +{										\
> +	int i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].name);	\
> +	return 0;								\
> +}
> +
> +
> +#define attribute_property_store(curr_val, type)				\
> +static ssize_t curr_val##_store(struct kobject *kobj,				\
> +				struct kobj_attribute *attr,			\
> +				const char *buf, size_t count)			\
> +{										\
> +	char *p = NULL;								\
> +	char *attr_value = NULL;						\
> +	char *attr_name = NULL;							\
> +	int i;									\
> +	int ret = -EIO;								\
> +										\
> +	attr_name = kstrdup(kobj->name, GFP_KERNEL);				\
> +	if (!attr_name)								\
> +		return -ENOMEM;							\

Since you don't modify attr_name (unlike attr_value) there is no need
to make a local copy, just use kobj->name directly instead of
the copy stored in attr_name.

> +	attr_value = kstrdup(buf, GFP_KERNEL);					\
> +	if (!attr_value)							\
> +		return -ENOMEM;							\
> +										\
> +	p = memchr(attr_value, '\n', count);					\
> +	if (p != NULL)								\
> +		*p = '\0';							\
> +										\
> +	i = get_##type##_instance_id(kobj);					\
> +	if (i >= 0)								\
> +		ret = validate_##type##_input(i, attr_value);			\
> +	if (!ret)								\
> +		ret = hp_set_attribute(attr_name, attr_value);			\
> +	if (!ret)								\
> +		update_##type##_value(i);					\
> +										\
> +	clear_all_passwords();							\

Why ?

At a minimum add a comment explaining this.

> +	kfree(attr_name);							\
> +	kfree(attr_value);							\
> +										\
> +	return ret ? ret : count;						\
> +}
> +
> +#define attribute_spm_n_property_show(name, type)				\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> +{									\
> +	return sprintf(buf, "%d\n", bioscfg_drv.type##_data.name);\
> +}
> +
> +#define attribute_spm_s_property_show(name, type)				\
> +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> +{									\
> +	return sprintf(buf, "%s\n", bioscfg_drv.type##_data.name);		\
> +}
> +
> +#define check_property_type(attr, prop, valuetype)\
> +	(attr##_obj[prop].type != valuetype)
> +
> +#define HPWMI_BINATTR_RW(_group, _name, _size)	\
> +static struct bin_attribute _group##_##_name =	\
> +__BIN_ATTR(_name, 0444 | 0200, _group##_##_name##_read, _group##_##_name##_write, _size)
> +
> +/*
> + * Prototypes
> + */
> +union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
> +int get_instance_count(const char *guid_string);
> +void strlcpy_attr(char *dest, char *src);
> +void update_attribute_permissions(u32 isReadOnly, struct kobj_attribute *current_val);
> +void friendly_user_name_update(char *path, const char *attr_name,
> +				char *attr_display, int attr_size);
> +
> +/* String attributes */
> +int populate_string_buffer_data(union acpi_object *str_obj,
> +			 int instance_id,
> +			 struct kobject *attr_name_kobj);
> +int populate_string_elements_from_buffer(union acpi_object *string_obj,
> +					 int instance_id,
> +					 enum hp_wmi_data_type type);
> +int alloc_string_data(void);
> +void exit_string_attributes(void);
> +int populate_string_package_data(union acpi_object *str_obj,
> +				 int instance_id,
> +				 struct kobject *attr_name_kobj);
> +int populate_string_elements_from_package(union acpi_object *str_obj,
> +						  int instance_id,
> +						  enum hp_wmi_data_type type);
> +
> +/* Integer attributes */
> +int populate_integer_buffer_data(union acpi_object *integer_obj,
> +			  int instance_id,
> +			  struct kobject *attr_name_kobj);
> +int populate_integer_elements_from_buffer(union acpi_object *integer_obj,
> +					  int instance_id,
> +					  enum hp_wmi_data_type type);
> +int alloc_integer_data(void);
> +void exit_integer_attributes(void);
> +int populate_integer_package_data(union acpi_object *integer_obj,
> +				  int instance_id,
> +				  struct kobject *attr_name_kobj);
> +int populate_integer_elements_from_package(union acpi_object *integer_obj,
> +						  int instance_id,
> +						  enum hp_wmi_data_type type);
> +
> +/* Enumeration attributes */
> +int populate_enumeration_buffer_data(union acpi_object *enum_obj,
> +			      int instance_id,
> +			      struct kobject *attr_name_kobj);
> +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> +					      int instance_id,
> +					      enum hp_wmi_data_type type);
> +int alloc_enumeration_data(void);
> +void exit_enumeration_attributes(void);
> +int populate_enumeration_package_data(union acpi_object *enum_obj,
> +				      int instance_id,
> +				      struct kobject *attr_name_kobj);
> +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> +					       int instance_id,
> +					       enum hp_wmi_data_type type);
> +
> +/* Ordered list */
> +int populate_ordered_list_buffer_data(union acpi_object *order_obj, int instance_id,
> +				      struct kobject *attr_name_kobj);
> +int populate_ordered_list_elements_from_buffer(union acpi_object *order_obj,
> +					       int instance_id,
> +					       enum hp_wmi_data_type
> +					       type);
> +int alloc_ordered_list_data(void);
> +void exit_ordered_list_attributes(void);
> +int populate_ordered_list_package_data(union acpi_object *order_obj,
> +				       int instance_id,
> +				       struct kobject *attr_name_kobj);
> +int populate_ordered_list_elements_from_package(union acpi_object *order_obj,
> +						int instance_id,
> +						enum hp_wmi_data_type type);
> +
> +/* Password authentication attributes */
> +int populate_password_buffer_data(union acpi_object *password_obj,
> +			   int instance_id,
> +			   struct kobject *attr_name_kobj);
> +int populate_password_elements_from_buffer(union acpi_object *password_obj,
> +					   int instance_id,
> +					   enum hp_wmi_data_type type);
> +int populate_password_package_data(union acpi_object *password_obj, int instance_id,
> +				   struct kobject *attr_name_kobj);
> +int populate_password_elements_from_package(union acpi_object *password_obj,
> +					   int instance_id,
> +					    enum hp_wmi_data_type type);
> +int alloc_password_data(void);
> +int alloc_secure_platform_data(void);
> +void exit_password_attributes(void);
> +void exit_secure_platform_attributes(void);
> +int populate_secure_platform_data(struct kobject *attr_name_kobj);
> +int password_is_set(const char *auth);
> +int check_spm_is_enabled(void);
> +int wmi_error_and_message(int error_code, char *message);
> +int hp_wmi_set_bios_setting(void *input_buffer, int input_size);
> +int hp_wmi_perform_query(int query, enum hp_wmi_command command,
> +				void *buffer, int insize, int outsize);
> +
> +/* Sure Start attributes */
> +void exit_sure_start_attributes(void);
> +int populate_sure_start_data(struct kobject *attr_name_kobj);
> +
> +/* Sure Admin Attributes */
> +void exit_sure_admin_attributes(void);
> +int populate_sure_admin_data(struct kobject *attr_name_kobj);
> +int hp_set_attribute(const char *a_name, const char *a_value);
> +int hp_set_attribute_with_payload(const char *a_name,
> +				  const char *a_value,
> +				  const char *auth_payload);
> +int update_attribute_value(char *attr_name, char *attr_value);
> +int hp_bios_settings_fill_buffer(void);
> +int hp_bios_settings_free_buffer(void);
> +int hp_bios_settings_realloc_buffer(char **buf, int *buf_size,
> +					   int *alloc_size);
> +int append_read_string_attributes(char *buf, int alloc_size,
> +					int instance,
> +					enum hp_wmi_data_type type);
> +int append_read_integer_attributes(char *buf, int alloc_size,
> +					 int instance,
> +					 enum hp_wmi_data_type type);
> +int append_read_enumeration_attributes(char *buf, int alloc_size,
> +					     int instance,
> +					     enum hp_wmi_data_type type);
> +int append_read_ordered_list_attributes(char *buf, int alloc_size,
> +					      int instance,
> +					      enum hp_wmi_data_type type);
> +int append_read_password_attributes(char *buf, int alloc_size,
> +					 int instance,
> +					 enum hp_wmi_data_type type);
> +int append_read_settings(enum hp_wmi_data_type type, char **buf,
> +			      int *buf_size, int *alloc_size);
> +int append_read_attributes(char **buf, int alloc_size,
> +				 int instance, enum hp_wmi_data_type type);
> +int set_bios_defaults(u8 defType);
> +int get_password_instance_for_type(const char *name);
> +int clear_all_passwords(void);
> +int clear_passwords(const int instance);
> +void exit_bios_attr_set_interface(void);
> +int init_bios_attr_set_interface(void);
> +size_t calculate_string_buffer(const char *str);
> +size_t calculate_security_buffer(const char *authentication);
> +void populate_security_buffer(u16 *buffer, const char *authentication);
> +ssize_t populate_string_buffer(u16 *buffer, size_t buffer_len, const char *str);
> +int set_new_password(const char *password_type, const char *new_password);
> +int init_bios_attr_pass_interface(void);
> +void exit_bios_attr_pass_interface(void);
> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str);
> +int get_integer_from_buffer(int **buffer, int *integer);
> +int get_string_from_buffer(u16 **buffer, char **str);
> +int convert_hexstr_to_str(char **hex, int input_len, char **str, int *len);
> +int convert_hexstr_to_int(char *str, int *int_value);
> +inline int encode_outsize_for_pvsz(int outsize);

Please drop the inline here, since this is just a function prototype it cannot
be inlined.

And please also drop the inline from the actual implementation, since
that is only used in other .c files.

> +
> +#endif
> diff --git a/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> new file mode 100644
> index 000000000000..e67e7c397c12
> --- /dev/null
> +++ b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> @@ -0,0 +1,521 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Functions corresponding to enumeration type attributes under
> + * BIOS Enumeration GUID for use with hp-bioscfg driver.
> + *
> + *  Copyright (c) 2022 HP Development Company, L.P.
> + */
> +
> +#include "bioscfg.h"
> +
> +get_instance_id(enumeration);
> +
> +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	int instance_id = get_enumeration_instance_id(kobj);
> +	union acpi_object *obj = NULL;
> +	ssize_t ret;
> +
> +	if (instance_id < 0)
> +		return -EIO;
> +
> +	/* need to use specific instance_id and guid combination to get right data */
> +	obj = get_wmiobj_pointer(instance_id, HP_WMI_BIOS_ENUMERATION_GUID);
> +	if (!obj)
> +		return -EIO;

Why get this obj if you are not using it at all ? The attribute_property_store()
macro updates bioscfg_drv.enumeration_data[instance_id].current_value on success,
so I believe this function can just 

> +
> +	ret = snprintf(buf, PAGE_SIZE, "%s\n",
> +		       bioscfg_drv.enumeration_data[instance_id].current_value);

please use sysfs_emit for this 

> +
> +	kfree(obj);
> +	return ret;
> +}
> +
> +
> +/*
> + * validate_enumeration_input() -
> + * Validate input of current_value against possible values
> + *
> + * @instance_id: The instance on which input is validated
> + * @buf: Input value
> + */
> +static int validate_enumeration_input(int instance_id, const char *buf)
> +{
> +	char *options = NULL;
> +	char *p;
> +	int ret = 0;
> +	int found = 0;
> +
> +	options = kstrdup(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +			  GFP_KERNEL);
> +
> +	if (!options) {
> +		ret = -ENOMEM;
> +		goto exit_validate_enum_input;
> +	}
> +
> +	/* Is it a read only attribute */
> +	if (bioscfg_drv.enumeration_data[instance_id].is_readonly) {
> +		ret = -EIO;
> +		goto exit_validate_enum_input;
> +	}

Please move this check to before the kstrdup and just 
directly return -EIO; instead of doing the goto.

> +
> +	while ((p = strsep(&options, ";")) != NULL) {
> +		if (!*p)
> +			continue;
> +
> +		if (!strcasecmp(p, buf)) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	if (!found) {
> +		ret = -EINVAL;
> +		goto exit_validate_enum_input;
> +	}
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].new_value,
> +		buf,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].new_value));

Why store a copy of buf in new_value?  This function is only called from
the attribute_property_store() with attr_value as buf parameter.

You can just also pass attr_value to update_##type##_value()
and then have update_enumeration_value() directly store attr_value
in current_value.

Doing things this way allows removing new_value from struct enumeration_data
all together resulting in a nice reduction in memory usage.

> +	/*
> +	 * set pending reboot flag depending on
> +	 * "RequiresPhysicalPresence" value
> +	 */
> +	if (bioscfg_drv.enumeration_data[instance_id].requires_physical_presence)
> +		bioscfg_drv.pending_reboot = TRUE;
> +
> +exit_validate_enum_input:
> +	kfree(options);
> +	return ret;
> +}
> +
> +static void update_enumeration_value(int instance_id)
> +{
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +		bioscfg_drv.enumeration_data[instance_id].new_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +}
> +
> +
> +attribute_s_property_show(display_name_language_code, enumeration);
> +static struct kobj_attribute enumeration_display_langcode =
> +		__ATTR_RO(display_name_language_code);
> +
> +attribute_s_property_show(display_name, enumeration);
> +static struct kobj_attribute  enumeration_display_name =
> +		__ATTR_RO(display_name);
> +
> +attribute_property_store(current_value, enumeration);
> +static struct kobj_attribute enumeration_current_val =
> +	__ATTR_RW_MODE(current_value, 0600);
> +
> +attribute_s_property_show(possible_values, enumeration);
> +static struct kobj_attribute  enumeration_poss_val =
> +		__ATTR_RO(possible_values);
> +
> +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
> +			 char *buf)
> +{
> +	return sprintf(buf, "enumeration\n");
> +}
> +static struct kobj_attribute enumeration_type =
> +		__ATTR_RO(type);
> +
> +static struct attribute *enumeration_attrs[] = {
> +	&enumeration_display_langcode.attr,
> +	&enumeration_display_name.attr,
> +	&enumeration_current_val.attr,
> +	&enumeration_poss_val.attr,
> +	&enumeration_type.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group enumeration_attr_group = {
> +	.attrs = enumeration_attrs,
> +};
> +
> +int alloc_enumeration_data(void)
> +{
> +	int ret = 0;
> +
> +	bioscfg_drv.enumeration_instances_count =
> +		get_instance_count(HP_WMI_BIOS_ENUMERATION_GUID);
> +
> +	bioscfg_drv.enumeration_data = kcalloc(bioscfg_drv.enumeration_instances_count,
> +					sizeof(struct enumeration_data), GFP_KERNEL);
> +	if (!bioscfg_drv.enumeration_data) {
> +		bioscfg_drv.enumeration_instances_count = 0;
> +		ret = -ENOMEM;
> +	}
> +	return ret;
> +}
> +
> +/*
> + * populate_enumeration_package_data() -
> + * Populate all properties of an instance under enumeration attribute
> + *
> + * @enum_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + */
> +int populate_enumeration_package_data(union acpi_object *enum_obj, int instance_id,
> +			struct kobject *attr_name_kobj)
> +{
> +	char *str_value = NULL;
> +	int str_len;
> +	int ret = 0;
> +
> +	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> +	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> +
> +	ret = convert_hexstr_to_str(&(enum_obj[NAME].string.pointer),
> +				    enum_obj[NAME].string.length,
> +				    &str_value, &str_len);
> +	if (ACPI_FAILURE(ret)) {
> +		pr_warn("Failed to populate enumeration package data. Error [0%0x]\n", ret);
> +		kfree(str_value);
> +		return ret;
> +	}

You have already done this convert_hexstr_to_str call in
hp_init_bios_attributes() and used it for the name of the passed in
struct kobject *attr_name_kobj, so you can just use attr_name_kobj->name
here, as you already do in the friendly_user_name_update() call below?

Also you use kobj->name in the get_##type##_instance_id() macro, and the
only reason why the enumeration_data[instance_id].attribute_name field
is necessary is for that function.

So dropping the above call and using kobj->name to intialize attribute_name
and display_name seems to make sense here ?




> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> +		str_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> +		str_value,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	kfree(str_value);
> +	str_value = NULL;

And then you can also drop this. Note there is no need to set str_value to NULL
here regardless since it is a local variable which will disappear when the
function ends.

> +
> +	populate_enumeration_elements_from_package(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> +	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> +				    &enumeration_current_val);
> +	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> +				  attr_name_kobj->name,
> +				   bioscfg_drv.enumeration_data[instance_id].display_name,
> +				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +}
> +
> +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> +					   int instance_id,
> +					   enum hp_wmi_data_type type)
> +{
> +	char *str_value = NULL;
> +	int value_len;
> +	int status = 0;
> +	u32 size = 0;
> +	u32 int_value;
> +	int elem = 0;
> +	int reqs;
> +	int eloc;
> +	int pos_values;
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> +		LANG_CODE_STR,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> +
> +	for (elem = 1, eloc = 1; elem < hp_wmi_elements_count[type]; elem++, eloc++) {
> +
> +		switch (enum_obj[elem].type) {
> +		case ACPI_TYPE_STRING:
> +
> +			if (PREREQUISITES != elem && ENUM_POSSIBLE_VALUES != elem) {
> +				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> +							       enum_obj[elem].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +			}
> +			break;
> +		case ACPI_TYPE_INTEGER:
> +			int_value = (u32)enum_obj[elem].integer.value;
> +			break;
> +		default:
> +			pr_warn("Unsupported object type [%d]\n", enum_obj[elem].type);
> +			continue;
> +		}
> +
> +		/* stop if extra counter is greater than total number
> +		 * of elements for enumeration type
> +		 */
> +		if (eloc == hp_wmi_elements_count[type])
> +			goto exit_enumeration_package;
> +
> +		/* Assign appropriate element value to corresponding field*/
> +		switch (eloc) {
> +		case VALUE:
> +			break;
> +		case PATH:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].path, str_value,
> +				sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> +			break;
> +		case IS_READONLY:
> +			bioscfg_drv.enumeration_data[instance_id].is_readonly = int_value;
> +			break;
> +		case DISPLAY_IN_UI:
> +			bioscfg_drv.enumeration_data[instance_id].display_in_ui = int_value;
> +			break;
> +		case REQUIRES_PHYSICAL_PRESENCE:
> +			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = int_value;
> +			break;
> +		case SEQUENCE:
> +			bioscfg_drv.enumeration_data[instance_id].sequence = int_value;
> +			break;
> +		case PREREQUISITE_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = int_value;
> +			if (int_value > 20)
> +				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> +			/*
> +			 * prerequisites element is omitted when
> +			 * prerequisitesSize value is zero.
> +			 */
> +			if (int_value == 0)
> +				eloc++;
> +			break;
> +		case PREREQUISITES:
> +			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> +
> +			for (reqs = 0; reqs < size; reqs++) {
> +				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> +							       enum_obj[elem].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					break;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> +					str_value,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				if (reqs != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +
> +				kfree(str_value);
> +				str_value = NULL;
> +			}
> +			break;
> +
> +		case SECURITY_LEVEL:
> +			bioscfg_drv.enumeration_data[instance_id].security_level = int_value;
> +			break;
> +
> +		case ENUM_CURRENT_VALUE:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +				str_value, sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +			break;
> +		case ENUM_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].size = int_value;
> +			break;
> +		case ENUM_POSSIBLE_VALUES:
> +			size = bioscfg_drv.enumeration_data[instance_id].size;
> +			for (pos_values = 0; pos_values < size; pos_values++) {
> +				status = convert_hexstr_to_str(&enum_obj[elem + pos_values].string.pointer,
> +							       enum_obj[elem  + pos_values].string.length,
> +							       &str_value, &value_len);
> +				if (ACPI_FAILURE(status))
> +					break;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +					str_value,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				if (pos_values < (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				kfree(str_value);
> +				str_value = NULL;
> +			}
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +
> +		kfree(str_value);
> +		str_value = NULL;
> +	}
> +
> +exit_enumeration_package:
> +		kfree(str_value);
> +		str_value = NULL;
> +	return 0;
> +}
> +
> +/*
> + * populate_enumeration_buffer_data() -
> + * Populate all properties of an instance under enumeration attribute
> + *
> + * @enum_obj: ACPI object with enumeration data
> + * @instance_id: The instance to enumerate
> + * @attr_name_kobj: The parent kernel object
> + * @enumeration_property_count: Total properties count under enumeration type
> + */
> +int populate_enumeration_buffer_data(union acpi_object *enum_obj, int instance_id,

Please replace:

union acpi_object *enum_obj

with:

u16 *buffer_ptr, size_t buffer_size,

for better readability, but also because actually walking obj->buffer.pointer
feels wrong. What if some other code later wants to also check the buffer,
but now obj->buffer.pointer is all of a sudden pointing to the end ?

Also you should pass in the (remaining) size and also pass this into
get_string_from_buffer() and into get_integer_from_buffer() and have
them check that they do not run pass the end of the buffer.

Also please adjust hp_init_bios_attributes() for it to have local:

u16 *buffer_ptr;
size_t buffer_size;

variables and for it to pass them into it's get_string_from_buffer()
call before it passes them to populate_enumeration_buffer_data()

These changes have 2 goals:

1. don't modify the contents of the acpi_object. In general for
 things like walking pointers you should use a local variable
 not change the members of a passed-by-reference struct, to
 avoid surprising the caller

2. add bounds check everywhere to ensure that you don't run
 past the end of the buffer while parsing it.


> +			      struct kobject *attr_name_kobj)
> +{
> +
> +	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> +	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> +		attr_name_kobj->name,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> +		attr_name_kobj->name,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	/* Populate enumeration elements */
> +	populate_enumeration_elements_from_buffer(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> +	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> +				    &enumeration_current_val);
> +	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> +				  attr_name_kobj->name,
> +				   bioscfg_drv.enumeration_data[instance_id].display_name,
> +				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> +
> +	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> +}
> +
> +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> +					      int instance_id,
> +					      enum hp_wmi_data_type type)
> +{
> +	int status;
> +	char *str = NULL;
> +	int elem;
> +	int reqs;
> +	int integer;
> +	int size = 0;
> +	int values;
> +
> +	elem = 0;
> +
> +	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> +		LANG_CODE_STR,
> +		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> +
> +	for (elem = 1; elem < 3; elem++) {
> +
> +		status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +		if (ACPI_FAILURE(status))
> +			continue;
> +
> +		switch (elem) {
> +		case VALUE:
> +			/* Skip 'Value' since 'CurrentValue' is reported. */
> +			break;
> +		case PATH:
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].path,
> +				str, sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +		kfree(str);
> +		str = NULL;
> +	}
> +
> +	for (elem = 3; elem < hp_wmi_elements_count[type]; elem++) {
> +		if (PREREQUISITES != elem && ENUM_CURRENT_VALUE != elem && ENUM_POSSIBLE_VALUES != elem)
> +			status = get_integer_from_buffer((int **)&enum_obj->buffer.pointer, (int *)&integer);
> +
> +		if (ACPI_FAILURE(status))
> +			continue;
> +		switch (elem) {
> +		case IS_READONLY:
> +			bioscfg_drv.enumeration_data[instance_id].is_readonly = integer;
> +			break;
> +		case DISPLAY_IN_UI:
> +			bioscfg_drv.enumeration_data[instance_id].display_in_ui = integer;
> +			break;
> +		case REQUIRES_PHYSICAL_PRESENCE:
> +			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = integer;
> +			break;
> +		case SEQUENCE:
> +			bioscfg_drv.enumeration_data[instance_id].sequence = integer;
> +			break;
> +		case PREREQUISITE_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = integer;
> +			if (integer > 20)
> +				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> +			break;
> +		case PREREQUISITES:
> +			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> +			for (reqs = 0; reqs < size; reqs++) {
> +				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> +					str,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				if (reqs != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> +				kfree(str);
> +				str = NULL;
> +			}
> +			break;
> +		case SECURITY_LEVEL:
> +			bioscfg_drv.enumeration_data[instance_id].security_level = integer;
> +			break;
> +		case ENUM_CURRENT_VALUE:
> +			status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> +				str,
> +				sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> +			break;
> +		case ENUM_SIZE:
> +			bioscfg_drv.enumeration_data[instance_id].size = integer;
> +			break;
> +		case ENUM_POSSIBLE_VALUES:
> +			size = bioscfg_drv.enumeration_data[instance_id].size;
> +			for (values = 0; values < size; values++) {
> +				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> +				if (ACPI_FAILURE(status))
> +					continue;
> +
> +				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> +					str,
> +					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				if (values != (size - 1))
> +					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> +						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> +				kfree(str);
> +				str = NULL;
> +			}
> +			break;
> +		default:
> +			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> +			break;
> +		}
> +		kfree(str);
> +		str = NULL;
> +	}
> +	kfree(str);
> +	str = NULL;
> +
> +	return 0;
> +}
> +
> +/**
> + * exit_enumeration_attributes() - Clear all attribute data
> + *
> + * Clears all data allocated for this group of attributes
> + */
> +void exit_enumeration_attributes(void)
> +{
> +	int instance_id;
> +
> +	for (instance_id = 0; instance_id < bioscfg_drv.enumeration_instances_count; instance_id++) {
> +		if (bioscfg_drv.enumeration_data[instance_id].attr_name_kobj)
> +			sysfs_remove_group(bioscfg_drv.enumeration_data[instance_id].attr_name_kobj,
> +								&enumeration_attr_group);
> +	}
> +	bioscfg_drv.enumeration_instances_count = 0;
> +
> +	kfree(bioscfg_drv.enumeration_data);
> +	bioscfg_drv.enumeration_data = NULL;
> +}


Regards,

Hans

Jorge Lopez Nov. 9, 2022, 5:24 p.m. UTC | #2

HI Hans,

Please see questions and comments below.

On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
>
> Hi Jorge,
>
> Review comments inline.
>
> On 10/20/22 22:10, Jorge Lopez wrote:
> > The purpose for this patch is submit HP BIOSCFG driver to be list of
> > HP Linux kernel drivers.  The driver include a total of 12 files
> > broken in several patches.  This is set 1 of 4.
> >
> > HP BIOS Configuration driver purpose is to provide a driver supporting
> > the latest sysfs class firmware attributes framework allowing the user
> > to change BIOS settings and security solutions on HP Inc.’s commercial
> > notebooks.
> >
> > Many features of HP Commercial PC’s can be managed using Windows
> > Management Instrumentation (WMI). WMI is an implementation of Web-Based
> > Enterprise Management (WBEM) that provides a standards-based interface
> > for changing and monitoring system settings.  HP BISOCFG driver provides
> > a native Linux solution and the exposed features facilitates the
> > migration to Linux environments.
> >
> > The Linux security features to be provided in hp-bioscfg driver enables
> > managing the BIOS settings and security solutions via sysfs, a virtual
> > filesystem that can be used by user-mode applications.   The new
> > documentation cover features such Secure Platform Management, Sure
> > Admin, and Sure Start.  Each section provides security feature
> > description and identifies sysfs directories and files exposed by
> > the driver.
> >
> > Many HP Commercial PC’s include a feature called Secure Platform
> > Management (SPM), which replaces older password-based BIOS settings
> > management with public key cryptography. PC secure product management
> > begins when a target system is provisioned with cryptographic keys
> > that are used to ensure the integrity of communications between system
> > management utilities and the BIOS.
> >
> > HP Commercial PC’s have several BIOS settings that control its behaviour
> > and capabilities, many of which are related to security. To prevent
> > unauthorized changes to these settings, the system can be configured
> > to use a Sure Admin cryptographic signature-based authorization string
> > that the BIOS will use to verify authorization to modify the setting.
> >
> > Signed-off-by: Jorge Lopez <[e-mail]>
> >
> > ---
> > Based on the latest platform-drivers-x86.git/for-next
> > ---
> >  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
> >  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
> >  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
> >  3 files changed, 1477 insertions(+)
> >  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >
> > diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> > new file mode 100644
> > index 000000000000..f0c919bf3ab0
> > --- /dev/null
> > +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> > @@ -0,0 +1,285 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to methods under BIOS interface GUID
> > + * for use with hp-bioscfg driver.
> > + *
> > + *  Copyright (c) 2022 Hewlett-Packard Inc.
> > + */
> > +
> > +#include <linux/wmi.h>
> > +#include "bioscfg.h"
> > +
> > +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> > +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
> > +#define SET_ATTRIBUTE_METHOD_ID              0x04
> > +
> > +/*
> > + * set_attribute() - Update an attribute value
> > + * @a_name: The attribute name
> > + * @a_value: The attribute value
> > + *
> > + * Sets an attribute to new value
> > + */
> > +int hp_set_attribute(const char *a_name, const char *a_value)
> > +{
> > +     size_t security_area_size;
> > +     size_t a_name_size, a_value_size;
> > +     u16 *buffer = NULL;
> > +     u16 *start = NULL;
> > +     int  buffer_size;
>
> You have 2 spaces between int and buffer_size here, please drop
> one.
>
>
> > +     int ret;
> > +     int instance;
> > +     char *auth_empty_value = " ";
> > +
> > +     mutex_lock(&bioscfg_drv.mutex);
> > +     if (!bioscfg_drv.bios_attr_wdev) {
> > +             ret = -ENODEV;
> > +             goto out_set_attribute;
> > +     }
> > +
> > +     instance = get_password_instance_for_type(SETUP_PASSWD);
> > +     if (instance < 0)
> > +             goto out_set_attribute;
> > +
> > +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> > +             strncpy(bioscfg_drv.password_data[instance].current_password,
> > +                     auth_empty_value,
> > +                     sizeof(bioscfg_drv.password_data[instance].current_password));
>
> strncpy does not guarantee 0 termination of the destination buffer,
> please use strscpy.
>
> > +
> > +     a_name_size = calculate_string_buffer(a_name);
> > +     a_value_size = calculate_string_buffer(a_value);
> > +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> > +     buffer_size = a_name_size + a_value_size + security_area_size;
> > +
> > +     buffer = kzalloc(buffer_size, GFP_KERNEL);
> > +     if (!buffer) {
> > +             ret = -ENOMEM;
> > +             goto out_set_attribute;
> > +     }
> > +
> > +     /* build variables to set */
> > +     start = buffer;
> > +     start = ascii_to_utf16_unicode(start, a_name);
> > +     if (!start)
> > +             goto out_set_attribute;
> > +
> > +     start = ascii_to_utf16_unicode(start, a_value);
> > +     if (!start)
> > +             goto out_set_attribute;
> > +
> > +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> > +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> > +
> > +
> > +out_set_attribute:
> > +     kfree(buffer);
> > +     mutex_unlock(&bioscfg_drv.mutex);
> > +     return ret;
> > +}
> > +
> > +/*
> > + * hp_wmi_perform_query
> > + *
> > + * query:    The commandtype (enum hp_wmi_commandtype)
> > + * write:    The command (enum hp_wmi_command)
> > + * buffer:   Buffer used as input and/or output
> > + * insize:   Size of input buffer
> > + * outsize:  Size of output buffer
> > + *
> > + * returns zero on success
> > + *         an HP WMI query specific error code (which is positive)
> > + *         -EINVAL if the query was not successful at all
> > + *         -EINVAL if the output buffer size exceeds buffersize
> > + *
> > + * Note: The buffersize must at least be the maximum of the input and output
> > + *       size. E.g. Battery info query is defined to have 1 byte input
> > + *       and 128 byte output. The caller would do:
> > + *       buffer = kzalloc(128, GFP_KERNEL);
> > + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> > + */
> > +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> > +{
> > +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> > +     struct bios_return *bios_return;
> > +     union acpi_object *obj = NULL;
> > +     struct bios_args *args = NULL;
> > +     int mid, actual_insize, actual_outsize;
> > +     size_t bios_args_size;
> > +     int ret;
> > +
> > +     mid = encode_outsize_for_pvsz(outsize);
> > +     if (WARN_ON(mid < 0))
> > +             return mid;
> > +
> > +     actual_insize = insize;
> > +     bios_args_size = struct_size(args, data, insize);
> > +     args = kmalloc(bios_args_size, GFP_KERNEL);
> > +     if (!args)
> > +             return -ENOMEM;
> > +
> > +     input.length = bios_args_size;
> > +     input.pointer = args;
> > +
> > +     args->signature = 0x55434553;
> > +     args->command = command;
> > +     args->commandtype = query;
> > +     args->datasize = insize;
> > +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
> > +
> > +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> > +     bioscfg_drv.last_wmi_status = ret;
> > +     if (ret)
> > +             goto out_free;
> > +
> > +     obj = output.pointer;
> > +     if (!obj) {
> > +             ret = -EINVAL;
> > +             goto out_free;
> > +     }
> > +
>
> You need to check the type of obj here before dereferencing
> obj as if it is a buffer.
>
> > +     bios_return = (struct bios_return *)obj->buffer.pointer;
> > +     ret = bios_return->return_code;
> > +     bioscfg_drv.last_wmi_status = ret;
> > +     if (ret) {
> > +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> > +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> > +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> > +             goto out_free;
> > +     }
> > +
> > +     /* Ignore output data of zero size */
> > +     if (!outsize)
> > +             goto out_free;
> > +
> > +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> > +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> > +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> > +
> > +out_free:
> > +     kfree(obj);
> > +     kfree(args);
> > +     return ret;
> > +}
> > +
> > +/*
> > + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> > + *
> > + * @p:   Unicode buffer address
> > + * @str: string to convert to unicode
> > + *
> > + * Returns a void pointer to the buffer containing unicode string
> > + */
> > +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> > +{
> > +     int len = strlen(str);
> > +     int ret;
> > +
> > +     /*
> > +      * Add null character when reading an empty string
> > +      */
> > +     if (len == 0) {
> > +             *p++ = 2;
> > +             *p++ = (u8)0x00;
> > +             return p;
>
> This does not match with calculate_string_buffer() which will
> return 2 for a 0 length string while you are using 4 bytes here.
>
> I guess this may also be why you need to use " " for
> auth_empty_value above, so as to avoid this bug.
>
HP BIOS expects 2 characters when an empty string is being converted
to u16 hence the reason for returning 2 instead of zero.  This is an
intended behavior and needed when  allocating a buffer and writing to
BIOS.

>
> > +     }
> > +     *p++ = len * 2;
> > +     ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
> > +
> > +     if (ret < 0) {
> > +             dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
> > +             goto ascii_to_utf16_unicode_out;
>
> You have an error here, but you don't return an error at the end of
> this function.
>
> Please for version 5 do the following:
>
> 1. Add a preparation patch which moves populate_string_buffer()
> and calculate_string_buffer() from
> drivers/platform/x86/dell/dell-wmi-sysman/sysman.c to
> drivers/platform/x86/wmi.c
>
Are you asking  to change sysman.c which is a DELL specific driver?
I don't have a DELL platform to validate the changes and I will be
doing the work on HP workday.   Sorry but I cannot do that.

> Renaming them to:
>
> size_t wmi_utf16_str_size(const char *str);
> ssize_t wmi_str_to_utf16_str(u16 *buffer, size_t buffer_len, const char *str);
>
> (adding these prototypes to include/linux/wmi.h)
>

I will make the changes requested but I'll wait for your response to
the previous comments regarding calculate_string_buffer()

> and make the dell-wmi-sysman code use these new helpers
>
> 2. Also use these new helpers in your own code instead
> of your own ascii_to_utf16_unicode() function
>
> > +     }
> > +
> > +     if ((ret * sizeof(u16)) > U16_MAX) {
> > +             dev_err(bioscfg_drv.class_dev, "Error string too long\n");
> > +             goto ascii_to_utf16_unicode_out;
> > +     }
> > +
> > +ascii_to_utf16_unicode_out:
> > +     p += len;
> > +     return p;
> > +}
> > +
> > +/*
> > + * hp_wmi_set_bios_setting - Set setting's value in BIOS
> > + *
> > + * @input_buffer: Input buffer address
> > + * @input_size:   Input buffer size
> > + *
> > + * Returns: Count of unicode characters written to BIOS if successful, otherwise
> > + *           -ENOMEM unable to allocate memory
> > + *           -EINVAL buffer not allocated or too small
> > + */
> > +int hp_wmi_set_bios_setting(void *input_buffer, int input_size)
> > +{
> > +     union acpi_object *obj;
> > +     struct acpi_buffer input = {input_size, input_buffer};
> > +     struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
> > +     int ret = 0;
> > +
> > +     ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output);
> > +
> > +     obj = output.pointer;
> > +     if (!obj)
> > +             return -EINVAL;
> > +
> > +     if (obj->type != ACPI_TYPE_INTEGER)
> > +             ret = -EINVAL;
> > +
> > +     ret = obj->integer.value;
> > +
> > +     kfree(obj);
> > +     return ret;
> > +}
> > +
> > +/*
> > + * set_bios_defaults() - Resets BIOS defaults
> > + *
> > + * @deftype: the type of BIOS value reset to issue.
> > + *
> > + * Resets BIOS defaults
> > + */
> > +int set_bios_defaults(u8 deftype)
> > +{
> > +     return -EOPNOTSUPP;
> > +}
>
> This function is not used anywhere, please drop it.
>
> > +
> > +static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
> > +{
> > +     mutex_lock(&bioscfg_drv.mutex);
> > +     bioscfg_drv.bios_attr_wdev = wdev;
> > +     mutex_unlock(&bioscfg_drv.mutex);
> > +     return 0;
> > +}
> > +
> > +static void bios_attr_set_interface_remove(struct wmi_device *wdev)
> > +{
> > +     mutex_lock(&bioscfg_drv.mutex);
> > +     bioscfg_drv.bios_attr_wdev = NULL;
> > +     mutex_unlock(&bioscfg_drv.mutex);
> > +}
> > +
> > +static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
> > +     { .guid_string = HP_WMI_BIOS_GUID},
> > +     { },
> > +};
> > +static struct wmi_driver bios_attr_set_interface_driver = {
> > +     .driver = {
> > +             .name = DRIVER_NAME
> > +     },
> > +     .probe = bios_attr_set_interface_probe,
> > +     .remove = bios_attr_set_interface_remove,
> > +     .id_table = bios_attr_set_interface_id_table,
> > +};
> > +
> > +int init_bios_attr_set_interface(void)
> > +{
> > +     return wmi_driver_register(&bios_attr_set_interface_driver);
> > +}
> > +
> > +void exit_bios_attr_set_interface(void)
> > +{
> > +     wmi_driver_unregister(&bios_attr_set_interface_driver);
> > +}
> > +
> > +MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
> > diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> > new file mode 100644
> > index 000000000000..4409481f84f2
> > --- /dev/null
> > +++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> > @@ -0,0 +1,671 @@
> > +/* SPDX-License-Identifier: GPL-2.0
> > + *
> > + * Definitions for kernel modules using hp_bioscfg driver
> > + *
> > + *  Copyright (c) 2022 HP Development Company, L.P.
> > + */
> > +
> > +#ifndef _HP_BIOSCFG_H_
> > +#define _HP_BIOSCFG_H_
> > +
> > +#include <linux/wmi.h>
> > +#include <linux/types.h>
> > +#include <linux/device.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/capability.h>
> > +#include <linux/nls.h>
> > +
> > +
> > +#define DRIVER_NAME  "hp-bioscfg"
> > +
> > +#define MAX_BUFF             512
> > +#define MAX_KEY_MOD          256
> > +#define MAX_PASSWD_SIZE              64
> > +#define MAX_MESSAGE_SIZE        256
> > +
> > +#define SPM_STR_DESC "Secure Platform Management"
> > +#define SPM_STR              "SPM"
> > +#define SURE_START_DESC "Sure Start"
> > +#define SURE_START_STR  "Sure_Start"
> > +#define SURE_ADMIN_DESC "Sure Admin"
> > +#define SURE_ADMIN_STR  "Sure_Admin"
> > +#define SETUP_PASSWD "Setup Password"
> > +#define POWER_ON_PASSWD      "Power-On Password"
> > +
> > +#define LANG_CODE_STR                "en_US.UTF-8"
> > +#define SCHEDULE_POWER_ON    "Scheduled Power-On"
> > +
> > +/* Sure Admin Functions */
> > +
> > +#define UTF_PREFIX   ((unsigned char *)"<utf-16/>")
> > +#define BEAM_PREFIX  ((unsigned char *)"<BEAM/>")
> > +
> > +/* mechanism - Authentication attribute */
> > +
> > +#define MAX_MECHANISM_TYPES 3
> > +
> > +enum mechanism_values {
> > +     PASSWORD        = 0x00,
> > +     NOT_PROVISION   = 0x00,
> > +     SIGNING_KEY     = 0x01,
> > +     ENDORSEMENT_KEY = 0x02
> > +};
> > +
> > +static const char * const spm_mechanism_types[] = {
> > +     "not provision",
> > +     "signing-key",
> > +     "endorsement-key"
> > +};
> > +
> > +static const char * const passwd_mechanism_types[] = {
> > +     "password",
> > +};
> > +
> > +/* roles - Authentication attribute */
> > +enum role_values {
> > +     BIOS_ADMIN      = 0x00,
> > +     POWER_ON        = 0x01,
> > +     BIOS_SPM        = 0x02
> > +};
> > +
> > +static const char * const role_type[] = {
> > +     "bios-admin",
> > +     "power-on",
> > +     "enhanced-bios-auth"
> > +};
> > +
> > +
> > +#define HP_WMI_BIOS_GUID             "5FB7F034-2C63-45e9-BE91-3D44E2C707E4"
> > +
> > +#define HP_WMI_BIOS_STRING_GUID              "988D08E3-68F4-4c35-AF3E-6A1B8106F83C"
> > +#define HP_WMI_BIOS_INTEGER_GUID     "8232DE3D-663D-4327-A8F4-E293ADB9BF05"
> > +#define HP_WMI_BIOS_ENUMERATION_GUID "2D114B49-2DFB-4130-B8FE-4A3C09E75133"
> > +#define HP_WMI_BIOS_ORDERED_LIST_GUID        "14EA9746-CE1F-4098-A0E0-7045CB4DA745"
> > +#define HP_WMI_BIOS_PASSWORD_GUID    "322F2028-0F84-4901-988E-015176049E2D"
> > +#define HP_WMI_SET_BIOS_SETTING_GUID "1F4C91EB-DC5C-460b-951D-C7CB9B4B8D5E"
> > +
> > +enum hp_wmi_spm_commandtype {
> > +     HPWMI_SECUREPLATFORM_GET_STATE  = 0x10,
> > +     HPWMI_SECUREPLATFORM_SET_KEK    = 0x11,
> > +     HPWMI_SECUREPLATFORM_SET_SK     = 0x12,
> > +};
> > +
> > +enum hp_wmi_surestart_commandtype {
> > +     HPWMI_SURESTART_GET_LOG_COUNT   = 0x01,
> > +     HPWMI_SURESTART_GET_LOG         = 0x02,
> > +};
> > +
> > +enum hp_wmi_command {
> > +     HPWMI_READ              = 0x01,
> > +     HPWMI_WRITE             = 0x02,
> > +     HPWMI_ODM               = 0x03,
> > +     HPWMI_SURESTART         = 0x20006,
> > +     HPWMI_GM                = 0x20008,
> > +     HPWMI_SECUREPLATFORM    = 0x20010,
> > +};
> > +
> > +struct bios_return {
> > +     u32 sigpass;
> > +     u32 return_code;
> > +};
> > +
> > +enum hp_return_value {
> > +     HPWMI_RET_WRONG_SIGNATURE       = 0x02,
> > +     HPWMI_RET_UNKNOWN_COMMAND       = 0x03,
> > +     HPWMI_RET_UNKNOWN_CMDTYPE       = 0x04,
> > +     HPWMI_RET_INVALID_PARAMETERS    = 0x05,
> > +};
> > +
> > +enum wmi_error_values {
> > +     SUCCESS                 = 0x00,
> > +     CMD_FAILED                      = 0x01,
> > +     INVALID_SIGN                    = 0x02,
> > +     INVALID_CMD_VALUE               = 0x03,
> > +     INVALID_CMD_TYPE                = 0x04,
> > +     INVALID_DATA_SIZE               = 0x05,
> > +     INVALID_CMD_PARAM               = 0x06,
> > +     ENCRYP_CMD_REQUIRED             = 0x07,
> > +     NO_SECURE_SESSION               = 0x08,
> > +     SECURE_SESSION_FOUND            = 0x09,
> > +     SECURE_SESSION_FAILED           = 0x0A,
> > +     AUTH_FAILED                     = 0x0B,
> > +     INVALID_BIOS_AUTH               = 0x0E,
> > +     NONCE_DID_NOT_MATCH             = 0x18,
> > +     GENERIC_ERROR                   = 0x1C,
> > +     BIOS_ADMIN_POLICY_NOT_MET       = 0x28,
> > +     BIOS_ADMIN_NOT_SET              = 0x38,
> > +     P21_NO_PROVISIONED              = 0x1000,
> > +     P21_PROVISION_IN_PROGRESS       = 0x1001,
> > +     P21_IN_USE                      = 0x1002,
> > +     HEP_NOT_ACTIVE                  = 0x1004,
> > +     HEP_ALREADY_SET         = 0x1006,
> > +     HEP_CHECK_STATE         = 0x1007
> > +};
> > +
> > +enum spm_features {
> > +     HEP_ENABLED             = 0x01,
> > +     PLATFORM_RECOVERY       = 0x02,
> > +     ENHANCED_BIOS_AUTH_MODE = 0x04
> > +};
> > +
> > +
> > +/*
> > + * struct bios_args buffer is dynamically allocated.  New WMI command types
> > + * were introduced that exceeds 128-byte data size.  Changes to handle
> > + * the data size allocation scheme were kept in hp_wmi_perform_qurey function.
> > + */
> > +struct bios_args {
> > +     u32 signature;
> > +     u32 command;
> > +     u32 commandtype;
> > +     u32 datasize;
> > +     u8 data[];
> > +};
> > +
> > +
> > +#pragma pack(1)
> > +struct secureplatform_provisioning_data {
> > +     u8 state;
> > +     u8 version[2];
> > +     u8 reserved1;
> > +     u32 features;
> > +     u32 nonce;
> > +     u8 reserved2[28];
> > +     u8 sk_mod[MAX_KEY_MOD];
> > +     u8 kek_mod[MAX_KEY_MOD];
> > +};
> > +
> > +#pragma pack()
> > +
> > +
> > +struct string_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +     u8 current_value[MAX_BUFF];
> > +     u8 new_value[MAX_BUFF];
> > +     u8 path[MAX_BUFF];
> > +     u32 is_readonly;
> > +     u32 display_in_ui;
> > +     u32 requires_physical_presence;
> > +     u32 sequence;
> > +     u32 prerequisitesize;
> > +     u8 prerequisites[MAX_BUFF];
> > +     u32 security_level;
> > +     u32 min_length;
> > +     u32 max_length;
> > +     u8 display_name_language_code[MAX_BUFF];
> > +     u32 type;
> > +};
> > +
> > +struct integer_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +     u32 current_value;
> > +     u32 new_value;
> > +     u8 path[MAX_BUFF];
> > +     u32 is_readonly;
> > +     u32 display_in_ui;
> > +     u32 requires_physical_presence;
> > +     u32 sequence;
> > +     u32 prerequisitesize;
> > +     u8 prerequisites[MAX_BUFF];
> > +     u32 security_level;
> > +     u32 lower_bound;
> > +     u32 upper_bound;
> > +     u32 scalar_increment;
> > +     u8 display_name_language_code[MAX_BUFF];
> > +     u32 type;
> > +};
> > +
> > +struct enumeration_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +     u8 path[MAX_BUFF];
> > +     u32 is_readonly;
> > +     u32 display_in_ui;
> > +     u32 requires_physical_presence;
> > +     u32 sequence;
> > +     u32 prerequisitesize;
> > +     u8 prerequisites[MAX_BUFF];
> > +     u32 security_level;
> > +     u8 current_value[MAX_BUFF];
> > +     u8 new_value[MAX_BUFF];
> > +     u32 size;
> > +     u8 possible_values[MAX_BUFF];
> > +     u8 display_name_language_code[MAX_BUFF];
> > +     u32 type;
> > +};
> > +
> > +struct ordered_list_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +     u8 current_value[MAX_BUFF];
> > +     u8 new_value[MAX_BUFF];
> > +     u8 path[MAX_BUFF];
> > +     u32 is_readonly;
> > +     u32 display_in_ui;
> > +     u32 requires_physical_presence;
> > +     u32 sequence;
> > +     u32 prerequisitesize;
> > +     u8 prerequisites[MAX_BUFF];
> > +     u32 security_level;
> > +     u32 size;
> > +     u8 elements[MAX_BUFF];
> > +     u8 display_name_language_code[MAX_BUFF];
> > +     u32 type;
> > +};
> > +
> > +struct password_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +     u8 current_password[MAX_PASSWD_SIZE];
> > +     u8 new_password[MAX_PASSWD_SIZE];
> > +     u8 path[MAX_BUFF];
> > +     u32 is_readonly;
> > +     u32 display_in_ui;
> > +     u32 requires_physical_presence;
> > +     u32 sequence;
> > +     u32 prerequisitesize;
> > +     u8 prerequisites[MAX_BUFF];
> > +     u32 security_level;
> > +     u32 min_password_length;
> > +     u32 max_password_length;
> > +     u32 encoding_size;
> > +     u8 supported_encoding[MAX_BUFF];
> > +     u8 display_name_language_code[MAX_BUFF];
> > +     u32 is_enabled;
> > +
> > +     // 'bios-admin' 'power-on'
> > +     u32 role;
> > +
> > +     //'password'
> > +     u32 mechanism;
> > +     u32 type;
> > +};
> > +
> > +struct secure_platform_data {
> > +     struct kobject *attr_name_kobj;
> > +     u8 attribute_name[MAX_BUFF];
> > +     u8 display_name[MAX_BUFF];
> > +
> > +     u8 *endorsement_key;
> > +     u8 *signing_key;
> > +
> > +     u32 is_enabled;
> > +     u32 mechanism;
> > +     u32 type;
> > +};
> > +
> > +struct bioscfg_priv {
> > +     struct wmi_device *password_attr_wdev;
> > +     struct wmi_device *bios_attr_wdev;
> > +     struct kset *authentication_dir_kset;
> > +     struct kset *main_dir_kset;
> > +     struct device *class_dev;
> > +     struct string_data *string_data;
> > +     u32 string_instances_count;
> > +     struct integer_data *integer_data;
> > +     u32 integer_instances_count;
> > +     struct enumeration_data *enumeration_data;
> > +     u32 enumeration_instances_count;
> > +     struct ordered_list_data *ordered_list_data;
> > +     u32 ordered_list_instances_count;
> > +     struct password_data *password_data;
> > +     u32 password_instances_count;
> > +
> > +     struct kobject *sure_start_attr_kobj;
> > +     struct kobject *sure_admin_attr_kobj;
> > +     struct secure_platform_data spm_data;
> > +
> > +     int  last_wmi_status;
> > +     bool pending_reboot;
> > +     struct mutex mutex;
> > +};
> > +
> > +/* global structure used by multiple WMI interfaces */
> > +extern struct bioscfg_priv bioscfg_drv;
> > +
> > +enum hp_wmi_data_type {
> > +     HPWMI_STRING_TYPE               = 0x00,
> > +     HPWMI_INTEGER_TYPE              = 0x01,
> > +     HPWMI_ENUMERATION_TYPE          = 0x02,
> > +     HPWMI_ORDERED_LIST_TYPE         = 0x03,
> > +     HPWMI_PASSWORD_TYPE             = 0x04,
> > +     HPWMI_SECURE_PLATFORM_TYPE      = 0x05,
> > +     HPWMI_SURE_START_TYPE           = 0x06,
> > +     HPWMI_SURE_ADMIN_TYPE           = 0x07,
> > +};
> > +
> > +enum hp_wmi_data_elements {
> > +
> > +     /* Common elements */
> > +     NAME = 0,
> > +     VALUE = 1,
> > +     PATH = 2,
> > +     IS_READONLY = 3,
> > +     DISPLAY_IN_UI = 4,
> > +     REQUIRES_PHYSICAL_PRESENCE = 5,
> > +     SEQUENCE = 6,
> > +     PREREQUISITE_SIZE = 7,
> > +     PREREQUISITES = 8,
> > +     SECURITY_LEVEL = 9,
> > +
> > +     /* String elements */
> > +     STR_MIN_LENGTH = 10,
> > +     STR_MAX_LENGTH = 11,
> > +
> > +     /* Integer elements */
> > +     INT_LOWER_BOUND = 10,
> > +     INT_UPPER_BOUND = 11,
> > +     INT_SCALAR_INCREMENT = 12,
> > +
> > +     /* Enumeration elements */
> > +     ENUM_CURRENT_VALUE = 10,
> > +     ENUM_SIZE = 11,
> > +     ENUM_POSSIBLE_VALUES = 12,
> > +
> > +     /* Ordered list elements */
> > +     ORD_LIST_SIZE = 10,
> > +     ORD_LIST_ELEMENTS = 11,
> > +
> > +     /* Password elements */
> > +     PSWD_MIN_LENGTH = 10,
> > +     PSWD_MAX_LENGTH = 11,
> > +     PSWD_SIZE = 12,
> > +     PSWD_SUPPORTED_ENCODING = 13,
> > +     PSWD_IS_SET = 14
> > +};
> > +
> > +
> > +static const int hp_wmi_elements_count[] = {
> > +     12,   // string
> > +     13,   // integer
> > +     13,   // enumeration
> > +     12,   // ordered list
> > +     15    // password
> > +};
> > +
> > +#define get_instance_id(type)                                                        \
> > +static int get_##type##_instance_id(struct kobject *kobj)                    \
> > +{                                                                            \
> > +     int i; \
> > +                                                             \
> > +     for (i = 0; i <= bioscfg_drv.type##_instances_count; i++) { \
> > +             if (!(strcmp(kobj->name, bioscfg_drv.type##_data[i].attribute_name))) \
> > +                     return i;                                               \
> > +     }                                                                       \
> > +     return -EIO;                                                            \
> > +}
> > +
> > +#define get_instance_id_for_attribute(type)                  \
> > +static int get_instance_id_for_##type(char *attr_name)               \
> > +{                                                                            \
> > +     int i;                                                                  \
> > +                                                                             \
> > +     for (i = 0; i < bioscfg_drv.type##_instances_count; i++) {              \
> > +             if (strcmp(bioscfg_drv.type##_data[i].attribute_name, attr_name) == 0)                                          \
> > +                     return i;                                               \
> > +     }                                                                       \
> > +     return -EIO;                                                            \
> > +}
> > +
> > +#define attribute_s_property_show(name, type)                                        \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,        \
> > +                        char *buf)                                           \
> > +{                                                                            \
> > +     int i = get_##type##_instance_id(kobj);                                 \
> > +     if (i >= 0)                                                             \
> > +             return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].name);   \
>
> Please use sysfs_emit instead of sprintf for this and all the other _show() functions.
>
> > +     return 0;                                                               \
> > +}
> > +/* There is no need to keep track of default and current values
> > + * separately
> > + */
> > +#define attribute_s_default_property_show(name, type, new_name)                      \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,        \
> > +                        char *buf)                                           \
> > +{                                                                            \
> > +     int i = get_##type##_instance_id(kobj);                                 \
> > +     if (i >= 0)                                                             \
> > +             return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].new_name);       \
> > +     return 0;                                                               \
> > +}
> > +
> > +#define attribute_n_default_property_show(name, type, new_name)                      \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,        \
> > +                        char *buf)                                           \
> > +{                                                                            \
> > +     int i = get_##type##_instance_id(kobj);                                 \
> > +     if (i >= 0)                                                             \
> > +             return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].new_name); \
> > +     return 0;                                                               \
> > +}
> > +
> > +#define attribute_n_property_show(name, type)                                        \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,        \
> > +                        char *buf)                                           \
> > +{                                                                            \
> > +     int i = get_##type##_instance_id(kobj);                                 \
> > +     if (i >= 0)                                                             \
> > +             return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].name);   \
> > +     return 0;                                                               \
> > +}
> > +
> > +
> > +#define attribute_property_store(curr_val, type)                             \
> > +static ssize_t curr_val##_store(struct kobject *kobj,                                \
> > +                             struct kobj_attribute *attr,                    \
> > +                             const char *buf, size_t count)                  \
> > +{                                                                            \
> > +     char *p = NULL;                                                         \
> > +     char *attr_value = NULL;                                                \
> > +     char *attr_name = NULL;                                                 \
> > +     int i;                                                                  \
> > +     int ret = -EIO;                                                         \
> > +                                                                             \
> > +     attr_name = kstrdup(kobj->name, GFP_KERNEL);                            \
> > +     if (!attr_name)                                                         \
> > +             return -ENOMEM;                                                 \
>
> Since you don't modify attr_name (unlike attr_value) there is no need
> to make a local copy, just use kobj->name directly instead of
> the copy stored in attr_name.
>
> > +     attr_value = kstrdup(buf, GFP_KERNEL);                                  \
> > +     if (!attr_value)                                                        \
> > +             return -ENOMEM;                                                 \
> > +                                                                             \
> > +     p = memchr(attr_value, '\n', count);                                    \
> > +     if (p != NULL)                                                          \
> > +             *p = '\0';                                                      \
> > +                                                                             \
> > +     i = get_##type##_instance_id(kobj);                                     \
> > +     if (i >= 0)                                                             \
> > +             ret = validate_##type##_input(i, attr_value);                   \
> > +     if (!ret)                                                               \
> > +             ret = hp_set_attribute(attr_name, attr_value);                  \
> > +     if (!ret)                                                               \
> > +             update_##type##_value(i);                                       \
> > +                                                                             \
> > +     clear_all_passwords();                                                  \
>
> Why ?
>
> At a minimum add a comment explaining this.
>
> > +     kfree(attr_name);                                                       \
> > +     kfree(attr_value);                                                      \
> > +                                                                             \
> > +     return ret ? ret : count;                                               \
> > +}
> > +
> > +#define attribute_spm_n_property_show(name, type)                            \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> > +{                                                                    \
> > +     return sprintf(buf, "%d\n", bioscfg_drv.type##_data.name);\
> > +}
> > +
> > +#define attribute_spm_s_property_show(name, type)                            \
> > +static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
> > +{                                                                    \
> > +     return sprintf(buf, "%s\n", bioscfg_drv.type##_data.name);              \
> > +}
> > +
> > +#define check_property_type(attr, prop, valuetype)\
> > +     (attr##_obj[prop].type != valuetype)
> > +
> > +#define HPWMI_BINATTR_RW(_group, _name, _size)       \
> > +static struct bin_attribute _group##_##_name =       \
> > +__BIN_ATTR(_name, 0444 | 0200, _group##_##_name##_read, _group##_##_name##_write, _size)
> > +
> > +/*
> > + * Prototypes
> > + */
> > +union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
> > +int get_instance_count(const char *guid_string);
> > +void strlcpy_attr(char *dest, char *src);
> > +void update_attribute_permissions(u32 isReadOnly, struct kobj_attribute *current_val);
> > +void friendly_user_name_update(char *path, const char *attr_name,
> > +                             char *attr_display, int attr_size);
> > +
> > +/* String attributes */
> > +int populate_string_buffer_data(union acpi_object *str_obj,
> > +                      int instance_id,
> > +                      struct kobject *attr_name_kobj);
> > +int populate_string_elements_from_buffer(union acpi_object *string_obj,
> > +                                      int instance_id,
> > +                                      enum hp_wmi_data_type type);
> > +int alloc_string_data(void);
> > +void exit_string_attributes(void);
> > +int populate_string_package_data(union acpi_object *str_obj,
> > +                              int instance_id,
> > +                              struct kobject *attr_name_kobj);
> > +int populate_string_elements_from_package(union acpi_object *str_obj,
> > +                                               int instance_id,
> > +                                               enum hp_wmi_data_type type);
> > +
> > +/* Integer attributes */
> > +int populate_integer_buffer_data(union acpi_object *integer_obj,
> > +                       int instance_id,
> > +                       struct kobject *attr_name_kobj);
> > +int populate_integer_elements_from_buffer(union acpi_object *integer_obj,
> > +                                       int instance_id,
> > +                                       enum hp_wmi_data_type type);
> > +int alloc_integer_data(void);
> > +void exit_integer_attributes(void);
> > +int populate_integer_package_data(union acpi_object *integer_obj,
> > +                               int instance_id,
> > +                               struct kobject *attr_name_kobj);
> > +int populate_integer_elements_from_package(union acpi_object *integer_obj,
> > +                                               int instance_id,
> > +                                               enum hp_wmi_data_type type);
> > +
> > +/* Enumeration attributes */
> > +int populate_enumeration_buffer_data(union acpi_object *enum_obj,
> > +                           int instance_id,
> > +                           struct kobject *attr_name_kobj);
> > +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> > +                                           int instance_id,
> > +                                           enum hp_wmi_data_type type);
> > +int alloc_enumeration_data(void);
> > +void exit_enumeration_attributes(void);
> > +int populate_enumeration_package_data(union acpi_object *enum_obj,
> > +                                   int instance_id,
> > +                                   struct kobject *attr_name_kobj);
> > +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> > +                                            int instance_id,
> > +                                            enum hp_wmi_data_type type);
> > +
> > +/* Ordered list */
> > +int populate_ordered_list_buffer_data(union acpi_object *order_obj, int instance_id,
> > +                                   struct kobject *attr_name_kobj);
> > +int populate_ordered_list_elements_from_buffer(union acpi_object *order_obj,
> > +                                            int instance_id,
> > +                                            enum hp_wmi_data_type
> > +                                            type);
> > +int alloc_ordered_list_data(void);
> > +void exit_ordered_list_attributes(void);
> > +int populate_ordered_list_package_data(union acpi_object *order_obj,
> > +                                    int instance_id,
> > +                                    struct kobject *attr_name_kobj);
> > +int populate_ordered_list_elements_from_package(union acpi_object *order_obj,
> > +                                             int instance_id,
> > +                                             enum hp_wmi_data_type type);
> > +
> > +/* Password authentication attributes */
> > +int populate_password_buffer_data(union acpi_object *password_obj,
> > +                        int instance_id,
> > +                        struct kobject *attr_name_kobj);
> > +int populate_password_elements_from_buffer(union acpi_object *password_obj,
> > +                                        int instance_id,
> > +                                        enum hp_wmi_data_type type);
> > +int populate_password_package_data(union acpi_object *password_obj, int instance_id,
> > +                                struct kobject *attr_name_kobj);
> > +int populate_password_elements_from_package(union acpi_object *password_obj,
> > +                                        int instance_id,
> > +                                         enum hp_wmi_data_type type);
> > +int alloc_password_data(void);
> > +int alloc_secure_platform_data(void);
> > +void exit_password_attributes(void);
> > +void exit_secure_platform_attributes(void);
> > +int populate_secure_platform_data(struct kobject *attr_name_kobj);
> > +int password_is_set(const char *auth);
> > +int check_spm_is_enabled(void);
> > +int wmi_error_and_message(int error_code, char *message);
> > +int hp_wmi_set_bios_setting(void *input_buffer, int input_size);
> > +int hp_wmi_perform_query(int query, enum hp_wmi_command command,
> > +                             void *buffer, int insize, int outsize);
> > +
> > +/* Sure Start attributes */
> > +void exit_sure_start_attributes(void);
> > +int populate_sure_start_data(struct kobject *attr_name_kobj);
> > +
> > +/* Sure Admin Attributes */
> > +void exit_sure_admin_attributes(void);
> > +int populate_sure_admin_data(struct kobject *attr_name_kobj);
> > +int hp_set_attribute(const char *a_name, const char *a_value);
> > +int hp_set_attribute_with_payload(const char *a_name,
> > +                               const char *a_value,
> > +                               const char *auth_payload);
> > +int update_attribute_value(char *attr_name, char *attr_value);
> > +int hp_bios_settings_fill_buffer(void);
> > +int hp_bios_settings_free_buffer(void);
> > +int hp_bios_settings_realloc_buffer(char **buf, int *buf_size,
> > +                                        int *alloc_size);
> > +int append_read_string_attributes(char *buf, int alloc_size,
> > +                                     int instance,
> > +                                     enum hp_wmi_data_type type);
> > +int append_read_integer_attributes(char *buf, int alloc_size,
> > +                                      int instance,
> > +                                      enum hp_wmi_data_type type);
> > +int append_read_enumeration_attributes(char *buf, int alloc_size,
> > +                                          int instance,
> > +                                          enum hp_wmi_data_type type);
> > +int append_read_ordered_list_attributes(char *buf, int alloc_size,
> > +                                           int instance,
> > +                                           enum hp_wmi_data_type type);
> > +int append_read_password_attributes(char *buf, int alloc_size,
> > +                                      int instance,
> > +                                      enum hp_wmi_data_type type);
> > +int append_read_settings(enum hp_wmi_data_type type, char **buf,
> > +                           int *buf_size, int *alloc_size);
> > +int append_read_attributes(char **buf, int alloc_size,
> > +                              int instance, enum hp_wmi_data_type type);
> > +int set_bios_defaults(u8 defType);
> > +int get_password_instance_for_type(const char *name);
> > +int clear_all_passwords(void);
> > +int clear_passwords(const int instance);
> > +void exit_bios_attr_set_interface(void);
> > +int init_bios_attr_set_interface(void);
> > +size_t calculate_string_buffer(const char *str);
> > +size_t calculate_security_buffer(const char *authentication);
> > +void populate_security_buffer(u16 *buffer, const char *authentication);
> > +ssize_t populate_string_buffer(u16 *buffer, size_t buffer_len, const char *str);
> > +int set_new_password(const char *password_type, const char *new_password);
> > +int init_bios_attr_pass_interface(void);
> > +void exit_bios_attr_pass_interface(void);
> > +void *ascii_to_utf16_unicode(u16 *p, const u8 *str);
> > +int get_integer_from_buffer(int **buffer, int *integer);
> > +int get_string_from_buffer(u16 **buffer, char **str);
> > +int convert_hexstr_to_str(char **hex, int input_len, char **str, int *len);
> > +int convert_hexstr_to_int(char *str, int *int_value);
> > +inline int encode_outsize_for_pvsz(int outsize);
>
> Please drop the inline here, since this is just a function prototype it cannot
> be inlined.
>
> And please also drop the inline from the actual implementation, since
> that is only used in other .c files.
>
> > +
> > +#endif
> > diff --git a/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> > new file mode 100644
> > index 000000000000..e67e7c397c12
> > --- /dev/null
> > +++ b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> > @@ -0,0 +1,521 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Functions corresponding to enumeration type attributes under
> > + * BIOS Enumeration GUID for use with hp-bioscfg driver.
> > + *
> > + *  Copyright (c) 2022 HP Development Company, L.P.
> > + */
> > +
> > +#include "bioscfg.h"
> > +
> > +get_instance_id(enumeration);
> > +
> > +static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> > +{
> > +     int instance_id = get_enumeration_instance_id(kobj);
> > +     union acpi_object *obj = NULL;
> > +     ssize_t ret;
> > +
> > +     if (instance_id < 0)
> > +             return -EIO;
> > +
> > +     /* need to use specific instance_id and guid combination to get right data */
> > +     obj = get_wmiobj_pointer(instance_id, HP_WMI_BIOS_ENUMERATION_GUID);
> > +     if (!obj)
> > +             return -EIO;
>
> Why get this obj if you are not using it at all ? The attribute_property_store()
> macro updates bioscfg_drv.enumeration_data[instance_id].current_value on success,
> so I believe this function can just
>
> > +
> > +     ret = snprintf(buf, PAGE_SIZE, "%s\n",
> > +                    bioscfg_drv.enumeration_data[instance_id].current_value);
>
> please use sysfs_emit for this
>
> > +
> > +     kfree(obj);
> > +     return ret;
> > +}
> > +
> > +
> > +/*
> > + * validate_enumeration_input() -
> > + * Validate input of current_value against possible values
> > + *
> > + * @instance_id: The instance on which input is validated
> > + * @buf: Input value
> > + */
> > +static int validate_enumeration_input(int instance_id, const char *buf)
> > +{
> > +     char *options = NULL;
> > +     char *p;
> > +     int ret = 0;
> > +     int found = 0;
> > +
> > +     options = kstrdup(bioscfg_drv.enumeration_data[instance_id].possible_values,
> > +                       GFP_KERNEL);
> > +
> > +     if (!options) {
> > +             ret = -ENOMEM;
> > +             goto exit_validate_enum_input;
> > +     }
> > +
> > +     /* Is it a read only attribute */
> > +     if (bioscfg_drv.enumeration_data[instance_id].is_readonly) {
> > +             ret = -EIO;
> > +             goto exit_validate_enum_input;
> > +     }
>
> Please move this check to before the kstrdup and just
> directly return -EIO; instead of doing the goto.
>
> > +
> > +     while ((p = strsep(&options, ";")) != NULL) {
> > +             if (!*p)
> > +                     continue;
> > +
> > +             if (!strcasecmp(p, buf)) {
> > +                     found = 1;
> > +                     break;
> > +             }
> > +     }
> > +
> > +     if (!found) {
> > +             ret = -EINVAL;
> > +             goto exit_validate_enum_input;
> > +     }
> > +
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].new_value,
> > +             buf,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].new_value));
>
> Why store a copy of buf in new_value?  This function is only called from
> the attribute_property_store() with attr_value as buf parameter.
>
> You can just also pass attr_value to update_##type##_value()
> and then have update_enumeration_value() directly store attr_value
> in current_value.
>
> Doing things this way allows removing new_value from struct enumeration_data
> all together resulting in a nice reduction in memory usage.
>
> > +     /*
> > +      * set pending reboot flag depending on
> > +      * "RequiresPhysicalPresence" value
> > +      */
> > +     if (bioscfg_drv.enumeration_data[instance_id].requires_physical_presence)
> > +             bioscfg_drv.pending_reboot = TRUE;
> > +
> > +exit_validate_enum_input:
> > +     kfree(options);
> > +     return ret;
> > +}
> > +
> > +static void update_enumeration_value(int instance_id)
> > +{
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> > +             bioscfg_drv.enumeration_data[instance_id].new_value,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> > +}
> > +
> > +
> > +attribute_s_property_show(display_name_language_code, enumeration);
> > +static struct kobj_attribute enumeration_display_langcode =
> > +             __ATTR_RO(display_name_language_code);
> > +
> > +attribute_s_property_show(display_name, enumeration);
> > +static struct kobj_attribute  enumeration_display_name =
> > +             __ATTR_RO(display_name);
> > +
> > +attribute_property_store(current_value, enumeration);
> > +static struct kobj_attribute enumeration_current_val =
> > +     __ATTR_RW_MODE(current_value, 0600);
> > +
> > +attribute_s_property_show(possible_values, enumeration);
> > +static struct kobj_attribute  enumeration_poss_val =
> > +             __ATTR_RO(possible_values);
> > +
> > +static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
> > +                      char *buf)
> > +{
> > +     return sprintf(buf, "enumeration\n");
> > +}
> > +static struct kobj_attribute enumeration_type =
> > +             __ATTR_RO(type);
> > +
> > +static struct attribute *enumeration_attrs[] = {
> > +     &enumeration_display_langcode.attr,
> > +     &enumeration_display_name.attr,
> > +     &enumeration_current_val.attr,
> > +     &enumeration_poss_val.attr,
> > +     &enumeration_type.attr,
> > +     NULL,
> > +};
> > +
> > +static const struct attribute_group enumeration_attr_group = {
> > +     .attrs = enumeration_attrs,
> > +};
> > +
> > +int alloc_enumeration_data(void)
> > +{
> > +     int ret = 0;
> > +
> > +     bioscfg_drv.enumeration_instances_count =
> > +             get_instance_count(HP_WMI_BIOS_ENUMERATION_GUID);
> > +
> > +     bioscfg_drv.enumeration_data = kcalloc(bioscfg_drv.enumeration_instances_count,
> > +                                     sizeof(struct enumeration_data), GFP_KERNEL);
> > +     if (!bioscfg_drv.enumeration_data) {
> > +             bioscfg_drv.enumeration_instances_count = 0;
> > +             ret = -ENOMEM;
> > +     }
> > +     return ret;
> > +}
> > +
> > +/*
> > + * populate_enumeration_package_data() -
> > + * Populate all properties of an instance under enumeration attribute
> > + *
> > + * @enum_obj: ACPI object with enumeration data
> > + * @instance_id: The instance to enumerate
> > + * @attr_name_kobj: The parent kernel object
> > + */
> > +int populate_enumeration_package_data(union acpi_object *enum_obj, int instance_id,
> > +                     struct kobject *attr_name_kobj)
> > +{
> > +     char *str_value = NULL;
> > +     int str_len;
> > +     int ret = 0;
> > +
> > +     bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> > +     bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> > +
> > +     ret = convert_hexstr_to_str(&(enum_obj[NAME].string.pointer),
> > +                                 enum_obj[NAME].string.length,
> > +                                 &str_value, &str_len);
> > +     if (ACPI_FAILURE(ret)) {
> > +             pr_warn("Failed to populate enumeration package data. Error [0%0x]\n", ret);
> > +             kfree(str_value);
> > +             return ret;
> > +     }
>
> You have already done this convert_hexstr_to_str call in
> hp_init_bios_attributes() and used it for the name of the passed in
> struct kobject *attr_name_kobj, so you can just use attr_name_kobj->name
> here, as you already do in the friendly_user_name_update() call below?
>
> Also you use kobj->name in the get_##type##_instance_id() macro, and the
> only reason why the enumeration_data[instance_id].attribute_name field
> is necessary is for that function.
>
> So dropping the above call and using kobj->name to intialize attribute_name
> and display_name seems to make sense here ?
>
>
>
>
> > +
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> > +             str_value,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> > +
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> > +             str_value,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> > +
> > +     kfree(str_value);
> > +     str_value = NULL;
>
> And then you can also drop this. Note there is no need to set str_value to NULL
> here regardless since it is a local variable which will disappear when the
> function ends.
>
> > +
> > +     populate_enumeration_elements_from_package(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> > +     update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> > +                                 &enumeration_current_val);
> > +     friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> > +                               attr_name_kobj->name,
> > +                                bioscfg_drv.enumeration_data[instance_id].display_name,
> > +                                sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> > +     return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> > +}
> > +
> > +int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
> > +                                        int instance_id,
> > +                                        enum hp_wmi_data_type type)
> > +{
> > +     char *str_value = NULL;
> > +     int value_len;
> > +     int status = 0;
> > +     u32 size = 0;
> > +     u32 int_value;
> > +     int elem = 0;
> > +     int reqs;
> > +     int eloc;
> > +     int pos_values;
> > +
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> > +             LANG_CODE_STR,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> > +
> > +     for (elem = 1, eloc = 1; elem < hp_wmi_elements_count[type]; elem++, eloc++) {
> > +
> > +             switch (enum_obj[elem].type) {
> > +             case ACPI_TYPE_STRING:
> > +
> > +                     if (PREREQUISITES != elem && ENUM_POSSIBLE_VALUES != elem) {
> > +                             status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> > +                                                            enum_obj[elem].string.length,
> > +                                                            &str_value, &value_len);
> > +                             if (ACPI_FAILURE(status))
> > +                                     continue;
> > +
> > +                     }
> > +                     break;
> > +             case ACPI_TYPE_INTEGER:
> > +                     int_value = (u32)enum_obj[elem].integer.value;
> > +                     break;
> > +             default:
> > +                     pr_warn("Unsupported object type [%d]\n", enum_obj[elem].type);
> > +                     continue;
> > +             }
> > +
> > +             /* stop if extra counter is greater than total number
> > +              * of elements for enumeration type
> > +              */
> > +             if (eloc == hp_wmi_elements_count[type])
> > +                     goto exit_enumeration_package;
> > +
> > +             /* Assign appropriate element value to corresponding field*/
> > +             switch (eloc) {
> > +             case VALUE:
> > +                     break;
> > +             case PATH:
> > +                     strscpy(bioscfg_drv.enumeration_data[instance_id].path, str_value,
> > +                             sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> > +                     break;
> > +             case IS_READONLY:
> > +                     bioscfg_drv.enumeration_data[instance_id].is_readonly = int_value;
> > +                     break;
> > +             case DISPLAY_IN_UI:
> > +                     bioscfg_drv.enumeration_data[instance_id].display_in_ui = int_value;
> > +                     break;
> > +             case REQUIRES_PHYSICAL_PRESENCE:
> > +                     bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = int_value;
> > +                     break;
> > +             case SEQUENCE:
> > +                     bioscfg_drv.enumeration_data[instance_id].sequence = int_value;
> > +                     break;
> > +             case PREREQUISITE_SIZE:
> > +                     bioscfg_drv.enumeration_data[instance_id].prerequisitesize = int_value;
> > +                     if (int_value > 20)
> > +                             pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> > +                     /*
> > +                      * prerequisites element is omitted when
> > +                      * prerequisitesSize value is zero.
> > +                      */
> > +                     if (int_value == 0)
> > +                             eloc++;
> > +                     break;
> > +             case PREREQUISITES:
> > +                     size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> > +
> > +                     for (reqs = 0; reqs < size; reqs++) {
> > +                             status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
> > +                                                            enum_obj[elem].string.length,
> > +                                                            &str_value, &value_len);
> > +                             if (ACPI_FAILURE(status))
> > +                                     break;
> > +
> > +                             strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> > +                                     str_value,
> > +                                     sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> > +                             if (reqs != (size - 1))
> > +                                     strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> > +                                             sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> > +
> > +                             kfree(str_value);
> > +                             str_value = NULL;
> > +                     }
> > +                     break;
> > +
> > +             case SECURITY_LEVEL:
> > +                     bioscfg_drv.enumeration_data[instance_id].security_level = int_value;
> > +                     break;
> > +
> > +             case ENUM_CURRENT_VALUE:
> > +                     strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> > +                             str_value, sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> > +                     break;
> > +             case ENUM_SIZE:
> > +                     bioscfg_drv.enumeration_data[instance_id].size = int_value;
> > +                     break;
> > +             case ENUM_POSSIBLE_VALUES:
> > +                     size = bioscfg_drv.enumeration_data[instance_id].size;
> > +                     for (pos_values = 0; pos_values < size; pos_values++) {
> > +                             status = convert_hexstr_to_str(&enum_obj[elem + pos_values].string.pointer,
> > +                                                            enum_obj[elem  + pos_values].string.length,
> > +                                                            &str_value, &value_len);
> > +                             if (ACPI_FAILURE(status))
> > +                                     break;
> > +
> > +                             strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> > +                                     str_value,
> > +                                     sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> > +                             if (pos_values < (size - 1))
> > +                                     strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> > +                                             sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> > +                             kfree(str_value);
> > +                             str_value = NULL;
> > +                     }
> > +                     break;
> > +             default:
> > +                     pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> > +                     break;
> > +             }
> > +
> > +             kfree(str_value);
> > +             str_value = NULL;
> > +     }
> > +
> > +exit_enumeration_package:
> > +             kfree(str_value);
> > +             str_value = NULL;
> > +     return 0;
> > +}
> > +
> > +/*
> > + * populate_enumeration_buffer_data() -
> > + * Populate all properties of an instance under enumeration attribute
> > + *
> > + * @enum_obj: ACPI object with enumeration data
> > + * @instance_id: The instance to enumerate
> > + * @attr_name_kobj: The parent kernel object
> > + * @enumeration_property_count: Total properties count under enumeration type
> > + */
> > +int populate_enumeration_buffer_data(union acpi_object *enum_obj, int instance_id,
>
> Please replace:
>
> union acpi_object *enum_obj
>
> with:
>
> u16 *buffer_ptr, size_t buffer_size,
>
> for better readability, but also because actually walking obj->buffer.pointer
> feels wrong. What if some other code later wants to also check the buffer,
> but now obj->buffer.pointer is all of a sudden pointing to the end ?
>
> Also you should pass in the (remaining) size and also pass this into
> get_string_from_buffer() and into get_integer_from_buffer() and have
> them check that they do not run pass the end of the buffer.
>
> Also please adjust hp_init_bios_attributes() for it to have local:
>
> u16 *buffer_ptr;
> size_t buffer_size;
>
> variables and for it to pass them into it's get_string_from_buffer()
> call before it passes them to populate_enumeration_buffer_data()
>
> These changes have 2 goals:
>
> 1. don't modify the contents of the acpi_object. In general for
>  things like walking pointers you should use a local variable
>  not change the members of a passed-by-reference struct, to
>  avoid surprising the caller
>
> 2. add bounds check everywhere to ensure that you don't run
>  past the end of the buffer while parsing it.
>
>
> > +                           struct kobject *attr_name_kobj)
> > +{
> > +
> > +     bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
> > +     bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
> > +             attr_name_kobj->name,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
> > +             attr_name_kobj->name,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> > +
> > +     /* Populate enumeration elements */
> > +     populate_enumeration_elements_from_buffer(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
> > +     update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
> > +                                 &enumeration_current_val);
> > +     friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
> > +                               attr_name_kobj->name,
> > +                                bioscfg_drv.enumeration_data[instance_id].display_name,
> > +                                sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
> > +
> > +     return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
> > +}
> > +
> > +int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
> > +                                           int instance_id,
> > +                                           enum hp_wmi_data_type type)
> > +{
> > +     int status;
> > +     char *str = NULL;
> > +     int elem;
> > +     int reqs;
> > +     int integer;
> > +     int size = 0;
> > +     int values;
> > +
> > +     elem = 0;
> > +
> > +     strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
> > +             LANG_CODE_STR,
> > +             sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
> > +
> > +     for (elem = 1; elem < 3; elem++) {
> > +
> > +             status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> > +             if (ACPI_FAILURE(status))
> > +                     continue;
> > +
> > +             switch (elem) {
> > +             case VALUE:
> > +                     /* Skip 'Value' since 'CurrentValue' is reported. */
> > +                     break;
> > +             case PATH:
> > +                     strscpy(bioscfg_drv.enumeration_data[instance_id].path,
> > +                             str, sizeof(bioscfg_drv.enumeration_data[instance_id].path));
> > +                     break;
> > +             default:
> > +                     pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> > +                     break;
> > +             }
> > +             kfree(str);
> > +             str = NULL;
> > +     }
> > +
> > +     for (elem = 3; elem < hp_wmi_elements_count[type]; elem++) {
> > +             if (PREREQUISITES != elem && ENUM_CURRENT_VALUE != elem && ENUM_POSSIBLE_VALUES != elem)
> > +                     status = get_integer_from_buffer((int **)&enum_obj->buffer.pointer, (int *)&integer);
> > +
> > +             if (ACPI_FAILURE(status))
> > +                     continue;
> > +             switch (elem) {
> > +             case IS_READONLY:
> > +                     bioscfg_drv.enumeration_data[instance_id].is_readonly = integer;
> > +                     break;
> > +             case DISPLAY_IN_UI:
> > +                     bioscfg_drv.enumeration_data[instance_id].display_in_ui = integer;
> > +                     break;
> > +             case REQUIRES_PHYSICAL_PRESENCE:
> > +                     bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = integer;
> > +                     break;
> > +             case SEQUENCE:
> > +                     bioscfg_drv.enumeration_data[instance_id].sequence = integer;
> > +                     break;
> > +             case PREREQUISITE_SIZE:
> > +                     bioscfg_drv.enumeration_data[instance_id].prerequisitesize = integer;
> > +                     if (integer > 20)
> > +                             pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
> > +                     break;
> > +             case PREREQUISITES:
> > +                     size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
> > +                     for (reqs = 0; reqs < size; reqs++) {
> > +                             status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> > +                             if (ACPI_FAILURE(status))
> > +                                     continue;
> > +
> > +                             strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
> > +                                     str,
> > +                                     sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> > +                             if (reqs != (size - 1))
> > +                                     strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
> > +                                             sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
> > +                             kfree(str);
> > +                             str = NULL;
> > +                     }
> > +                     break;
> > +             case SECURITY_LEVEL:
> > +                     bioscfg_drv.enumeration_data[instance_id].security_level = integer;
> > +                     break;
> > +             case ENUM_CURRENT_VALUE:
> > +                     status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> > +                     strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
> > +                             str,
> > +                             sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
> > +                     break;
> > +             case ENUM_SIZE:
> > +                     bioscfg_drv.enumeration_data[instance_id].size = integer;
> > +                     break;
> > +             case ENUM_POSSIBLE_VALUES:
> > +                     size = bioscfg_drv.enumeration_data[instance_id].size;
> > +                     for (values = 0; values < size; values++) {
> > +                             status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
> > +                             if (ACPI_FAILURE(status))
> > +                                     continue;
> > +
> > +                             strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
> > +                                     str,
> > +                                     sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> > +                             if (values != (size - 1))
> > +                                     strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
> > +                                             sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
> > +                             kfree(str);
> > +                             str = NULL;
> > +                     }
> > +                     break;
> > +             default:
> > +                     pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
> > +                     break;
> > +             }
> > +             kfree(str);
> > +             str = NULL;
> > +     }
> > +     kfree(str);
> > +     str = NULL;
> > +
> > +     return 0;
> > +}
> > +
> > +/**
> > + * exit_enumeration_attributes() - Clear all attribute data
> > + *
> > + * Clears all data allocated for this group of attributes
> > + */
> > +void exit_enumeration_attributes(void)
> > +{
> > +     int instance_id;
> > +
> > +     for (instance_id = 0; instance_id < bioscfg_drv.enumeration_instances_count; instance_id++) {
> > +             if (bioscfg_drv.enumeration_data[instance_id].attr_name_kobj)
> > +                     sysfs_remove_group(bioscfg_drv.enumeration_data[instance_id].attr_name_kobj,
> > +                                                             &enumeration_attr_group);
> > +     }
> > +     bioscfg_drv.enumeration_instances_count = 0;
> > +
> > +     kfree(bioscfg_drv.enumeration_data);
> > +     bioscfg_drv.enumeration_data = NULL;
> > +}
>
>
> Regards,
>
> Hans
>

Hans de Goede Nov. 9, 2022, 6:10 p.m. UTC | #3

Hi,

On 11/9/22 18:24, Jorge Lopez wrote:
> HI Hans,
> 
> Please see questions and comments below.
> 
> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
>>
>> Hi Jorge,
>>
>> Review comments inline.
>>
>> On 10/20/22 22:10, Jorge Lopez wrote:
>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
>>> HP Linux kernel drivers.  The driver include a total of 12 files
>>> broken in several patches.  This is set 1 of 4.
>>>
>>> HP BIOS Configuration driver purpose is to provide a driver supporting
>>> the latest sysfs class firmware attributes framework allowing the user
>>> to change BIOS settings and security solutions on HP Inc.’s commercial
>>> notebooks.
>>>
>>> Many features of HP Commercial PC’s can be managed using Windows
>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
>>> Enterprise Management (WBEM) that provides a standards-based interface
>>> for changing and monitoring system settings.  HP BISOCFG driver provides
>>> a native Linux solution and the exposed features facilitates the
>>> migration to Linux environments.
>>>
>>> The Linux security features to be provided in hp-bioscfg driver enables
>>> managing the BIOS settings and security solutions via sysfs, a virtual
>>> filesystem that can be used by user-mode applications.   The new
>>> documentation cover features such Secure Platform Management, Sure
>>> Admin, and Sure Start.  Each section provides security feature
>>> description and identifies sysfs directories and files exposed by
>>> the driver.
>>>
>>> Many HP Commercial PC’s include a feature called Secure Platform
>>> Management (SPM), which replaces older password-based BIOS settings
>>> management with public key cryptography. PC secure product management
>>> begins when a target system is provisioned with cryptographic keys
>>> that are used to ensure the integrity of communications between system
>>> management utilities and the BIOS.
>>>
>>> HP Commercial PC’s have several BIOS settings that control its behaviour
>>> and capabilities, many of which are related to security. To prevent
>>> unauthorized changes to these settings, the system can be configured
>>> to use a Sure Admin cryptographic signature-based authorization string
>>> that the BIOS will use to verify authorization to modify the setting.
>>>
>>> Signed-off-by: Jorge Lopez <[e-mail]>
>>>
>>> ---
>>> Based on the latest platform-drivers-x86.git/for-next
>>> ---
>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>>>  3 files changed, 1477 insertions(+)
>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
>>>
>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>> new file mode 100644
>>> index 000000000000..f0c919bf3ab0
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>> @@ -0,0 +1,285 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Functions corresponding to methods under BIOS interface GUID
>>> + * for use with hp-bioscfg driver.
>>> + *
>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
>>> + */
>>> +
>>> +#include <linux/wmi.h>
>>> +#include "bioscfg.h"
>>> +
>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
>>> +
>>> +/*
>>> + * set_attribute() - Update an attribute value
>>> + * @a_name: The attribute name
>>> + * @a_value: The attribute value
>>> + *
>>> + * Sets an attribute to new value
>>> + */
>>> +int hp_set_attribute(const char *a_name, const char *a_value)
>>> +{
>>> +     size_t security_area_size;
>>> +     size_t a_name_size, a_value_size;
>>> +     u16 *buffer = NULL;
>>> +     u16 *start = NULL;
>>> +     int  buffer_size;
>>
>> You have 2 spaces between int and buffer_size here, please drop
>> one.
>>
>>
>>> +     int ret;
>>> +     int instance;
>>> +     char *auth_empty_value = " ";
>>> +
>>> +     mutex_lock(&bioscfg_drv.mutex);
>>> +     if (!bioscfg_drv.bios_attr_wdev) {
>>> +             ret = -ENODEV;
>>> +             goto out_set_attribute;
>>> +     }
>>> +
>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
>>> +     if (instance < 0)
>>> +             goto out_set_attribute;
>>> +
>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
>>> +                     auth_empty_value,
>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
>>
>> strncpy does not guarantee 0 termination of the destination buffer,
>> please use strscpy.
>>
>>> +
>>> +     a_name_size = calculate_string_buffer(a_name);
>>> +     a_value_size = calculate_string_buffer(a_value);
>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
>>> +
>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
>>> +     if (!buffer) {
>>> +             ret = -ENOMEM;
>>> +             goto out_set_attribute;
>>> +     }
>>> +
>>> +     /* build variables to set */
>>> +     start = buffer;
>>> +     start = ascii_to_utf16_unicode(start, a_name);
>>> +     if (!start)
>>> +             goto out_set_attribute;
>>> +
>>> +     start = ascii_to_utf16_unicode(start, a_value);
>>> +     if (!start)
>>> +             goto out_set_attribute;
>>> +
>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
>>> +
>>> +
>>> +out_set_attribute:
>>> +     kfree(buffer);
>>> +     mutex_unlock(&bioscfg_drv.mutex);
>>> +     return ret;
>>> +}
>>> +
>>> +/*
>>> + * hp_wmi_perform_query
>>> + *
>>> + * query:    The commandtype (enum hp_wmi_commandtype)
>>> + * write:    The command (enum hp_wmi_command)
>>> + * buffer:   Buffer used as input and/or output
>>> + * insize:   Size of input buffer
>>> + * outsize:  Size of output buffer
>>> + *
>>> + * returns zero on success
>>> + *         an HP WMI query specific error code (which is positive)
>>> + *         -EINVAL if the query was not successful at all
>>> + *         -EINVAL if the output buffer size exceeds buffersize
>>> + *
>>> + * Note: The buffersize must at least be the maximum of the input and output
>>> + *       size. E.g. Battery info query is defined to have 1 byte input
>>> + *       and 128 byte output. The caller would do:
>>> + *       buffer = kzalloc(128, GFP_KERNEL);
>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
>>> + */
>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
>>> +{
>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
>>> +     struct bios_return *bios_return;
>>> +     union acpi_object *obj = NULL;
>>> +     struct bios_args *args = NULL;
>>> +     int mid, actual_insize, actual_outsize;
>>> +     size_t bios_args_size;
>>> +     int ret;
>>> +
>>> +     mid = encode_outsize_for_pvsz(outsize);
>>> +     if (WARN_ON(mid < 0))
>>> +             return mid;
>>> +
>>> +     actual_insize = insize;
>>> +     bios_args_size = struct_size(args, data, insize);
>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
>>> +     if (!args)
>>> +             return -ENOMEM;
>>> +
>>> +     input.length = bios_args_size;
>>> +     input.pointer = args;
>>> +
>>> +     args->signature = 0x55434553;
>>> +     args->command = command;
>>> +     args->commandtype = query;
>>> +     args->datasize = insize;
>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
>>> +
>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
>>> +     bioscfg_drv.last_wmi_status = ret;
>>> +     if (ret)
>>> +             goto out_free;
>>> +
>>> +     obj = output.pointer;
>>> +     if (!obj) {
>>> +             ret = -EINVAL;
>>> +             goto out_free;
>>> +     }
>>> +
>>
>> You need to check the type of obj here before dereferencing
>> obj as if it is a buffer.
>>
>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
>>> +     ret = bios_return->return_code;
>>> +     bioscfg_drv.last_wmi_status = ret;
>>> +     if (ret) {
>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
>>> +             goto out_free;
>>> +     }
>>> +
>>> +     /* Ignore output data of zero size */
>>> +     if (!outsize)
>>> +             goto out_free;
>>> +
>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
>>> +
>>> +out_free:
>>> +     kfree(obj);
>>> +     kfree(args);
>>> +     return ret;
>>> +}
>>> +
>>> +/*
>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
>>> + *
>>> + * @p:   Unicode buffer address
>>> + * @str: string to convert to unicode
>>> + *
>>> + * Returns a void pointer to the buffer containing unicode string
>>> + */
>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
>>> +{
>>> +     int len = strlen(str);
>>> +     int ret;
>>> +
>>> +     /*
>>> +      * Add null character when reading an empty string
>>> +      */
>>> +     if (len == 0) {
>>> +             *p++ = 2;
>>> +             *p++ = (u8)0x00;
>>> +             return p;
>>
>> This does not match with calculate_string_buffer() which will
>> return 2 for a 0 length string while you are using 4 bytes here.
>>
>> I guess this may also be why you need to use " " for
>> auth_empty_value above, so as to avoid this bug.
>>
> HP BIOS expects 2 characters when an empty string is being converted
> to u16 hence the reason for returning 2 instead of zero.  This is an
> intended behavior and needed when  allocating a buffer and writing to
> BIOS.

Right I understand that, it wants 2 characters for the 16 bit length
word, but why not write 0 to that 16 bit length word. Why actually
say the string-buffer length is 2 bytes long / and then write
a 16-bit word with value 0?

What you are doing now creates a 4 byte buffer like this:

u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }

Why not just create a 2 byte buffer like this:

u8 buf[2] = { 0x00, 0x00 }

?


Also I'm wondering why the empty auth string is " " and
not "" ?


> 
>>
>>> +     }
>>> +     *p++ = len * 2;
>>> +     ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
>>> +
>>> +     if (ret < 0) {
>>> +             dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
>>> +             goto ascii_to_utf16_unicode_out;
>>
>> You have an error here, but you don't return an error at the end of
>> this function.
>>
>> Please for version 5 do the following:
>>
>> 1. Add a preparation patch which moves populate_string_buffer()
>> and calculate_string_buffer() from
>> drivers/platform/x86/dell/dell-wmi-sysman/sysman.c to
>> drivers/platform/x86/wmi.c
>>
> Are you asking  to change sysman.c which is a DELL specific driver?
> I don't have a DELL platform to validate the changes and I will be
> doing the work on HP workday.   Sorry but I cannot do that.

I'm asking you to move the functions to drivers/platform/x86/wmi.c,
rename them and check they still compile. So that these functions
can be shared. You won't be changing the code at all, just the function
names.

And I have a Dell Latitude laptop where I can verify that
dell-wmi-sysman still works.



> 
>> Renaming them to:
>>
>> size_t wmi_utf16_str_size(const char *str);
>> ssize_t wmi_str_to_utf16_str(u16 *buffer, size_t buffer_len, const char *str);
>>
>> (adding these prototypes to include/linux/wmi.h)
>>
> 
> I will make the changes requested but I'll wait for your response to
> the previous comments regarding calculate_string_buffer()

Ok.


Regards,

Hans


p.s.

Next time if you are replying to a really long email like my previous
one, please remove any not relevant quoted text from the reply, to
make it easier to find the parts where you actually reply.

Jorge Lopez Nov. 9, 2022, 8 p.m. UTC | #4

Hi Hans,

On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
>
> Hi,
>
> On 11/9/22 18:24, Jorge Lopez wrote:
> > HI Hans,
> >
> > Please see questions and comments below.
> >
> > On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
> >>
> >> Hi Jorge,
> >>
> >> Review comments inline.
> >>
> >> On 10/20/22 22:10, Jorge Lopez wrote:
> >>> The purpose for this patch is submit HP BIOSCFG driver to be list of
> >>> HP Linux kernel drivers.  The driver include a total of 12 files
> >>> broken in several patches.  This is set 1 of 4.
> >>>
> >>> HP BIOS Configuration driver purpose is to provide a driver supporting
> >>> the latest sysfs class firmware attributes framework allowing the user
> >>> to change BIOS settings and security solutions on HP Inc.’s commercial
> >>> notebooks.
> >>>
> >>> Many features of HP Commercial PC’s can be managed using Windows
> >>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> >>> Enterprise Management (WBEM) that provides a standards-based interface
> >>> for changing and monitoring system settings.  HP BISOCFG driver provides
> >>> a native Linux solution and the exposed features facilitates the
> >>> migration to Linux environments.
> >>>
> >>> The Linux security features to be provided in hp-bioscfg driver enables
> >>> managing the BIOS settings and security solutions via sysfs, a virtual
> >>> filesystem that can be used by user-mode applications.   The new
> >>> documentation cover features such Secure Platform Management, Sure
> >>> Admin, and Sure Start.  Each section provides security feature
> >>> description and identifies sysfs directories and files exposed by
> >>> the driver.
> >>>
> >>> Many HP Commercial PC’s include a feature called Secure Platform
> >>> Management (SPM), which replaces older password-based BIOS settings
> >>> management with public key cryptography. PC secure product management
> >>> begins when a target system is provisioned with cryptographic keys
> >>> that are used to ensure the integrity of communications between system
> >>> management utilities and the BIOS.
> >>>
> >>> HP Commercial PC’s have several BIOS settings that control its behaviour
> >>> and capabilities, many of which are related to security. To prevent
> >>> unauthorized changes to these settings, the system can be configured
> >>> to use a Sure Admin cryptographic signature-based authorization string
> >>> that the BIOS will use to verify authorization to modify the setting.
> >>>
> >>> Signed-off-by: Jorge Lopez <[e-mail]>
> >>>
> >>> ---
> >>> Based on the latest platform-drivers-x86.git/for-next
> >>> ---
> >>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
> >>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
> >>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
> >>>  3 files changed, 1477 insertions(+)
> >>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >>>
> >>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>> new file mode 100644
> >>> index 000000000000..f0c919bf3ab0
> >>> --- /dev/null
> >>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>> @@ -0,0 +1,285 @@
> >>> +// SPDX-License-Identifier: GPL-2.0
> >>> +/*
> >>> + * Functions corresponding to methods under BIOS interface GUID
> >>> + * for use with hp-bioscfg driver.
> >>> + *
> >>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> >>> + */
> >>> +
> >>> +#include <linux/wmi.h>
> >>> +#include "bioscfg.h"
> >>> +
> >>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> >>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
> >>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
> >>> +
> >>> +/*
> >>> + * set_attribute() - Update an attribute value
> >>> + * @a_name: The attribute name
> >>> + * @a_value: The attribute value
> >>> + *
> >>> + * Sets an attribute to new value
> >>> + */
> >>> +int hp_set_attribute(const char *a_name, const char *a_value)
> >>> +{
> >>> +     size_t security_area_size;
> >>> +     size_t a_name_size, a_value_size;
> >>> +     u16 *buffer = NULL;
> >>> +     u16 *start = NULL;
> >>> +     int  buffer_size;
> >>
> >> You have 2 spaces between int and buffer_size here, please drop
> >> one.
> >>
> >>
> >>> +     int ret;
> >>> +     int instance;
> >>> +     char *auth_empty_value = " ";
> >>> +
> >>> +     mutex_lock(&bioscfg_drv.mutex);
> >>> +     if (!bioscfg_drv.bios_attr_wdev) {
> >>> +             ret = -ENODEV;
> >>> +             goto out_set_attribute;
> >>> +     }
> >>> +
> >>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
> >>> +     if (instance < 0)
> >>> +             goto out_set_attribute;
> >>> +
> >>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> >>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
> >>> +                     auth_empty_value,
> >>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
> >>
> >> strncpy does not guarantee 0 termination of the destination buffer,
> >> please use strscpy.
> >>
> >>> +
> >>> +     a_name_size = calculate_string_buffer(a_name);
> >>> +     a_value_size = calculate_string_buffer(a_value);
> >>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> >>> +     buffer_size = a_name_size + a_value_size + security_area_size;
> >>> +
> >>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
> >>> +     if (!buffer) {
> >>> +             ret = -ENOMEM;
> >>> +             goto out_set_attribute;
> >>> +     }
> >>> +
> >>> +     /* build variables to set */
> >>> +     start = buffer;
> >>> +     start = ascii_to_utf16_unicode(start, a_name);
> >>> +     if (!start)
> >>> +             goto out_set_attribute;
> >>> +
> >>> +     start = ascii_to_utf16_unicode(start, a_value);
> >>> +     if (!start)
> >>> +             goto out_set_attribute;
> >>> +
> >>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> >>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> >>> +
> >>> +
> >>> +out_set_attribute:
> >>> +     kfree(buffer);
> >>> +     mutex_unlock(&bioscfg_drv.mutex);
> >>> +     return ret;
> >>> +}
> >>> +
> >>> +/*
> >>> + * hp_wmi_perform_query
> >>> + *
> >>> + * query:    The commandtype (enum hp_wmi_commandtype)
> >>> + * write:    The command (enum hp_wmi_command)
> >>> + * buffer:   Buffer used as input and/or output
> >>> + * insize:   Size of input buffer
> >>> + * outsize:  Size of output buffer
> >>> + *
> >>> + * returns zero on success
> >>> + *         an HP WMI query specific error code (which is positive)
> >>> + *         -EINVAL if the query was not successful at all
> >>> + *         -EINVAL if the output buffer size exceeds buffersize
> >>> + *
> >>> + * Note: The buffersize must at least be the maximum of the input and output
> >>> + *       size. E.g. Battery info query is defined to have 1 byte input
> >>> + *       and 128 byte output. The caller would do:
> >>> + *       buffer = kzalloc(128, GFP_KERNEL);
> >>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> >>> + */
> >>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> >>> +{
> >>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> >>> +     struct bios_return *bios_return;
> >>> +     union acpi_object *obj = NULL;
> >>> +     struct bios_args *args = NULL;
> >>> +     int mid, actual_insize, actual_outsize;
> >>> +     size_t bios_args_size;
> >>> +     int ret;
> >>> +
> >>> +     mid = encode_outsize_for_pvsz(outsize);
> >>> +     if (WARN_ON(mid < 0))
> >>> +             return mid;
> >>> +
> >>> +     actual_insize = insize;
> >>> +     bios_args_size = struct_size(args, data, insize);
> >>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
> >>> +     if (!args)
> >>> +             return -ENOMEM;
> >>> +
> >>> +     input.length = bios_args_size;
> >>> +     input.pointer = args;
> >>> +
> >>> +     args->signature = 0x55434553;
> >>> +     args->command = command;
> >>> +     args->commandtype = query;
> >>> +     args->datasize = insize;
> >>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
> >>> +
> >>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> >>> +     bioscfg_drv.last_wmi_status = ret;
> >>> +     if (ret)
> >>> +             goto out_free;
> >>> +
> >>> +     obj = output.pointer;
> >>> +     if (!obj) {
> >>> +             ret = -EINVAL;
> >>> +             goto out_free;
> >>> +     }
> >>> +
> >>
> >> You need to check the type of obj here before dereferencing
> >> obj as if it is a buffer.
> >>
> >>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
> >>> +     ret = bios_return->return_code;
> >>> +     bioscfg_drv.last_wmi_status = ret;
> >>> +     if (ret) {
> >>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> >>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> >>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> >>> +             goto out_free;
> >>> +     }
> >>> +
> >>> +     /* Ignore output data of zero size */
> >>> +     if (!outsize)
> >>> +             goto out_free;
> >>> +
> >>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> >>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> >>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> >>> +
> >>> +out_free:
> >>> +     kfree(obj);
> >>> +     kfree(args);
> >>> +     return ret;
> >>> +}
> >>> +
> >>> +/*
> >>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> >>> + *
> >>> + * @p:   Unicode buffer address
> >>> + * @str: string to convert to unicode
> >>> + *
> >>> + * Returns a void pointer to the buffer containing unicode string
> >>> + */
> >>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> >>> +{
> >>> +     int len = strlen(str);
> >>> +     int ret;
> >>> +
> >>> +     /*
> >>> +      * Add null character when reading an empty string
> >>> +      */
> >>> +     if (len == 0) {
> >>> +             *p++ = 2;
> >>> +             *p++ = (u8)0x00;
> >>> +             return p;
> >>
> >> This does not match with calculate_string_buffer() which will
> >> return 2 for a 0 length string while you are using 4 bytes here.
> >>
> >> I guess this may also be why you need to use " " for
> >> auth_empty_value above, so as to avoid this bug.
> >>
> > HP BIOS expects 2 characters when an empty string is being converted
> > to u16 hence the reason for returning 2 instead of zero.  This is an
> > intended behavior and needed when  allocating a buffer and writing to
> > BIOS.
>
> Right I understand that, it wants 2 characters for the 16 bit length
> word, but why not write 0 to that 16 bit length word. Why actually
> say the string-buffer length is 2 bytes long / and then write
> a 16-bit word with value 0?
>
> What you are doing now creates a 4 byte buffer like this:
>
> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
>
> Why not just create a 2 byte buffer like this:
>
> u8 buf[2] = { 0x00, 0x00 }
>
> ?
>
>
> Also I'm wondering why the empty auth string is " " and
> not "" ?
>
>

The string returned for an empty string is 4 bytes.  The returned
string includes two bytes for the string size in bytes and the
remaining bytes are the string.
Size =  0x02, 0x00
String = 0x00, 0x00

All strings return include the string size in bytes followed by the u16 string


> >
> >>
> >>> +     }
> >>> +     *p++ = len * 2;
> >>> +     ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
> >>> +
> >>> +     if (ret < 0) {
> >>> +             dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
> >>> +             goto ascii_to_utf16_unicode_out;
> >>
> >> You have an error here, but you don't return an error at the end of
> >> this function.
> >>
> >> Please for version 5 do the following:
> >>
> >> 1. Add a preparation patch which moves populate_string_buffer()
> >> and calculate_string_buffer() from
> >> drivers/platform/x86/dell/dell-wmi-sysman/sysman.c to
> >> drivers/platform/x86/wmi.c
> >>
> > Are you asking  to change sysman.c which is a DELL specific driver?
> > I don't have a DELL platform to validate the changes and I will be
> > doing the work on HP workday.   Sorry but I cannot do that.
>
> I'm asking you to move the functions to drivers/platform/x86/wmi.c,
> rename them and check they still compile. So that these functions
> can be shared. You won't be changing the code at all, just the function
> names.
>
> And I have a Dell Latitude laptop where I can verify that
> dell-wmi-sysman still works.
>
>
>
> >
> >> Renaming them to:
> >>
> >> size_t wmi_utf16_str_size(const char *str);
> >> ssize_t wmi_str_to_utf16_str(u16 *buffer, size_t buffer_len, const char *str);
> >>
> >> (adding these prototypes to include/linux/wmi.h)
> >>
> >
> > I will make the changes requested but I'll wait for your response to
> > the previous comments regarding calculate_string_buffer()
>
> Ok.
>
>
> Regards,
>
> Hans
>
>
> p.s.
>
> Next time if you are replying to a really long email like my previous
> one, please remove any not relevant quoted text from the reply, to
> make it easier to find the parts where you actually reply.
>
ok.
>

Hans de Goede Nov. 9, 2022, 8:05 p.m. UTC | #5

Hi,

On 11/9/22 21:00, Jorge Lopez wrote:
> Hi Hans,
> 
> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
>>
>> Hi,
>>
>> On 11/9/22 18:24, Jorge Lopez wrote:
>>> HI Hans,
>>>
>>> Please see questions and comments below.
>>>
>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
>>>>
>>>> Hi Jorge,
>>>>
>>>> Review comments inline.
>>>>
>>>> On 10/20/22 22:10, Jorge Lopez wrote:
>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
>>>>> HP Linux kernel drivers.  The driver include a total of 12 files
>>>>> broken in several patches.  This is set 1 of 4.
>>>>>
>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
>>>>> the latest sysfs class firmware attributes framework allowing the user
>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
>>>>> notebooks.
>>>>>
>>>>> Many features of HP Commercial PC’s can be managed using Windows
>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
>>>>> Enterprise Management (WBEM) that provides a standards-based interface
>>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
>>>>> a native Linux solution and the exposed features facilitates the
>>>>> migration to Linux environments.
>>>>>
>>>>> The Linux security features to be provided in hp-bioscfg driver enables
>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
>>>>> filesystem that can be used by user-mode applications.   The new
>>>>> documentation cover features such Secure Platform Management, Sure
>>>>> Admin, and Sure Start.  Each section provides security feature
>>>>> description and identifies sysfs directories and files exposed by
>>>>> the driver.
>>>>>
>>>>> Many HP Commercial PC’s include a feature called Secure Platform
>>>>> Management (SPM), which replaces older password-based BIOS settings
>>>>> management with public key cryptography. PC secure product management
>>>>> begins when a target system is provisioned with cryptographic keys
>>>>> that are used to ensure the integrity of communications between system
>>>>> management utilities and the BIOS.
>>>>>
>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
>>>>> and capabilities, many of which are related to security. To prevent
>>>>> unauthorized changes to these settings, the system can be configured
>>>>> to use a Sure Admin cryptographic signature-based authorization string
>>>>> that the BIOS will use to verify authorization to modify the setting.
>>>>>
>>>>> Signed-off-by: Jorge Lopez <[e-mail]>
>>>>>
>>>>> ---
>>>>> Based on the latest platform-drivers-x86.git/for-next
>>>>> ---
>>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>>>>>  3 files changed, 1477 insertions(+)
>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
>>>>>
>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>> new file mode 100644
>>>>> index 000000000000..f0c919bf3ab0
>>>>> --- /dev/null
>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>> @@ -0,0 +1,285 @@
>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>> +/*
>>>>> + * Functions corresponding to methods under BIOS interface GUID
>>>>> + * for use with hp-bioscfg driver.
>>>>> + *
>>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
>>>>> + */
>>>>> +
>>>>> +#include <linux/wmi.h>
>>>>> +#include "bioscfg.h"
>>>>> +
>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
>>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
>>>>> +
>>>>> +/*
>>>>> + * set_attribute() - Update an attribute value
>>>>> + * @a_name: The attribute name
>>>>> + * @a_value: The attribute value
>>>>> + *
>>>>> + * Sets an attribute to new value
>>>>> + */
>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
>>>>> +{
>>>>> +     size_t security_area_size;
>>>>> +     size_t a_name_size, a_value_size;
>>>>> +     u16 *buffer = NULL;
>>>>> +     u16 *start = NULL;
>>>>> +     int  buffer_size;
>>>>
>>>> You have 2 spaces between int and buffer_size here, please drop
>>>> one.
>>>>
>>>>
>>>>> +     int ret;
>>>>> +     int instance;
>>>>> +     char *auth_empty_value = " ";
>>>>> +
>>>>> +     mutex_lock(&bioscfg_drv.mutex);
>>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
>>>>> +             ret = -ENODEV;
>>>>> +             goto out_set_attribute;
>>>>> +     }
>>>>> +
>>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
>>>>> +     if (instance < 0)
>>>>> +             goto out_set_attribute;
>>>>> +
>>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
>>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
>>>>> +                     auth_empty_value,
>>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
>>>>
>>>> strncpy does not guarantee 0 termination of the destination buffer,
>>>> please use strscpy.
>>>>
>>>>> +
>>>>> +     a_name_size = calculate_string_buffer(a_name);
>>>>> +     a_value_size = calculate_string_buffer(a_value);
>>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
>>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
>>>>> +
>>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
>>>>> +     if (!buffer) {
>>>>> +             ret = -ENOMEM;
>>>>> +             goto out_set_attribute;
>>>>> +     }
>>>>> +
>>>>> +     /* build variables to set */
>>>>> +     start = buffer;
>>>>> +     start = ascii_to_utf16_unicode(start, a_name);
>>>>> +     if (!start)
>>>>> +             goto out_set_attribute;
>>>>> +
>>>>> +     start = ascii_to_utf16_unicode(start, a_value);
>>>>> +     if (!start)
>>>>> +             goto out_set_attribute;
>>>>> +
>>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
>>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
>>>>> +
>>>>> +
>>>>> +out_set_attribute:
>>>>> +     kfree(buffer);
>>>>> +     mutex_unlock(&bioscfg_drv.mutex);
>>>>> +     return ret;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * hp_wmi_perform_query
>>>>> + *
>>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
>>>>> + * write:    The command (enum hp_wmi_command)
>>>>> + * buffer:   Buffer used as input and/or output
>>>>> + * insize:   Size of input buffer
>>>>> + * outsize:  Size of output buffer
>>>>> + *
>>>>> + * returns zero on success
>>>>> + *         an HP WMI query specific error code (which is positive)
>>>>> + *         -EINVAL if the query was not successful at all
>>>>> + *         -EINVAL if the output buffer size exceeds buffersize
>>>>> + *
>>>>> + * Note: The buffersize must at least be the maximum of the input and output
>>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
>>>>> + *       and 128 byte output. The caller would do:
>>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
>>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
>>>>> + */
>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
>>>>> +{
>>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
>>>>> +     struct bios_return *bios_return;
>>>>> +     union acpi_object *obj = NULL;
>>>>> +     struct bios_args *args = NULL;
>>>>> +     int mid, actual_insize, actual_outsize;
>>>>> +     size_t bios_args_size;
>>>>> +     int ret;
>>>>> +
>>>>> +     mid = encode_outsize_for_pvsz(outsize);
>>>>> +     if (WARN_ON(mid < 0))
>>>>> +             return mid;
>>>>> +
>>>>> +     actual_insize = insize;
>>>>> +     bios_args_size = struct_size(args, data, insize);
>>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
>>>>> +     if (!args)
>>>>> +             return -ENOMEM;
>>>>> +
>>>>> +     input.length = bios_args_size;
>>>>> +     input.pointer = args;
>>>>> +
>>>>> +     args->signature = 0x55434553;
>>>>> +     args->command = command;
>>>>> +     args->commandtype = query;
>>>>> +     args->datasize = insize;
>>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
>>>>> +
>>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>> +     if (ret)
>>>>> +             goto out_free;
>>>>> +
>>>>> +     obj = output.pointer;
>>>>> +     if (!obj) {
>>>>> +             ret = -EINVAL;
>>>>> +             goto out_free;
>>>>> +     }
>>>>> +
>>>>
>>>> You need to check the type of obj here before dereferencing
>>>> obj as if it is a buffer.
>>>>
>>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
>>>>> +     ret = bios_return->return_code;
>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>> +     if (ret) {
>>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
>>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
>>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
>>>>> +             goto out_free;
>>>>> +     }
>>>>> +
>>>>> +     /* Ignore output data of zero size */
>>>>> +     if (!outsize)
>>>>> +             goto out_free;
>>>>> +
>>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
>>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
>>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
>>>>> +
>>>>> +out_free:
>>>>> +     kfree(obj);
>>>>> +     kfree(args);
>>>>> +     return ret;
>>>>> +}
>>>>> +
>>>>> +/*
>>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
>>>>> + *
>>>>> + * @p:   Unicode buffer address
>>>>> + * @str: string to convert to unicode
>>>>> + *
>>>>> + * Returns a void pointer to the buffer containing unicode string
>>>>> + */
>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
>>>>> +{
>>>>> +     int len = strlen(str);
>>>>> +     int ret;
>>>>> +
>>>>> +     /*
>>>>> +      * Add null character when reading an empty string
>>>>> +      */
>>>>> +     if (len == 0) {
>>>>> +             *p++ = 2;
>>>>> +             *p++ = (u8)0x00;
>>>>> +             return p;
>>>>
>>>> This does not match with calculate_string_buffer() which will
>>>> return 2 for a 0 length string while you are using 4 bytes here.
>>>>
>>>> I guess this may also be why you need to use " " for
>>>> auth_empty_value above, so as to avoid this bug.
>>>>
>>> HP BIOS expects 2 characters when an empty string is being converted
>>> to u16 hence the reason for returning 2 instead of zero.  This is an
>>> intended behavior and needed when  allocating a buffer and writing to
>>> BIOS.
>>
>> Right I understand that, it wants 2 characters for the 16 bit length
>> word, but why not write 0 to that 16 bit length word. Why actually
>> say the string-buffer length is 2 bytes long / and then write
>> a 16-bit word with value 0?
>>
>> What you are doing now creates a 4 byte buffer like this:
>>
>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
>>
>> Why not just create a 2 byte buffer like this:
>>
>> u8 buf[2] = { 0x00, 0x00 }
>>
>> ?
>>
>>
>> Also I'm wondering why the empty auth string is " " and
>> not "" ?
>>
>>
> 
> The string returned for an empty string is 4 bytes.  The returned
> string includes two bytes for the string size in bytes and the
> remaining bytes are the string.
> Size =  0x02, 0x00
> String = 0x00, 0x00
> 
> All strings return include the string size in bytes followed by the u16 string

Right I understand that, but why is the "String = 0x00, 0x00"
there ? All the non-0-length strings are not 0 terminated,
why does the zero length string needs to be specified as length 2
(1 u16) and then have that u16 be a 0 terminator ?

Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
an empty string?

###

Also you did not answer this separate question:

I'm wondering why the empty auth string is " " and not "" ?


Regards,

Hans

Jorge Lopez Nov. 9, 2022, 8:52 p.m. UTC | #6

On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <[e-mail]> wrote:
>
> Hi,
>
> On 11/9/22 21:00, Jorge Lopez wrote:
> > Hi Hans,
> >
> > On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
> >>
> >> Hi,
> >>
> >> On 11/9/22 18:24, Jorge Lopez wrote:
> >>> HI Hans,
> >>>
> >>> Please see questions and comments below.
> >>>
> >>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
> >>>>
> >>>> Hi Jorge,
> >>>>
> >>>> Review comments inline.
> >>>>
> >>>> On 10/20/22 22:10, Jorge Lopez wrote:
> >>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
> >>>>> HP Linux kernel drivers.  The driver include a total of 12 files
> >>>>> broken in several patches.  This is set 1 of 4.
> >>>>>
> >>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
> >>>>> the latest sysfs class firmware attributes framework allowing the user
> >>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
> >>>>> notebooks.
> >>>>>
> >>>>> Many features of HP Commercial PC’s can be managed using Windows
> >>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> >>>>> Enterprise Management (WBEM) that provides a standards-based interface
> >>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
> >>>>> a native Linux solution and the exposed features facilitates the
> >>>>> migration to Linux environments.
> >>>>>
> >>>>> The Linux security features to be provided in hp-bioscfg driver enables
> >>>>> managing the BIOS settings and security solutions via sysfs, a virtual
> >>>>> filesystem that can be used by user-mode applications.   The new
> >>>>> documentation cover features such Secure Platform Management, Sure
> >>>>> Admin, and Sure Start.  Each section provides security feature
> >>>>> description and identifies sysfs directories and files exposed by
> >>>>> the driver.
> >>>>>
> >>>>> Many HP Commercial PC’s include a feature called Secure Platform
> >>>>> Management (SPM), which replaces older password-based BIOS settings
> >>>>> management with public key cryptography. PC secure product management
> >>>>> begins when a target system is provisioned with cryptographic keys
> >>>>> that are used to ensure the integrity of communications between system
> >>>>> management utilities and the BIOS.
> >>>>>
> >>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
> >>>>> and capabilities, many of which are related to security. To prevent
> >>>>> unauthorized changes to these settings, the system can be configured
> >>>>> to use a Sure Admin cryptographic signature-based authorization string
> >>>>> that the BIOS will use to verify authorization to modify the setting.
> >>>>>
> >>>>> Signed-off-by: Jorge Lopez <[e-mail]>
> >>>>>
> >>>>> ---
> >>>>> Based on the latest platform-drivers-x86.git/for-next
> >>>>> ---
> >>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
> >>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
> >>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
> >>>>>  3 files changed, 1477 insertions(+)
> >>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >>>>>
> >>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>> new file mode 100644
> >>>>> index 000000000000..f0c919bf3ab0
> >>>>> --- /dev/null
> >>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>> @@ -0,0 +1,285 @@
> >>>>> +// SPDX-License-Identifier: GPL-2.0
> >>>>> +/*
> >>>>> + * Functions corresponding to methods under BIOS interface GUID
> >>>>> + * for use with hp-bioscfg driver.
> >>>>> + *
> >>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> >>>>> + */
> >>>>> +
> >>>>> +#include <linux/wmi.h>
> >>>>> +#include "bioscfg.h"
> >>>>> +
> >>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> >>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
> >>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
> >>>>> +
> >>>>> +/*
> >>>>> + * set_attribute() - Update an attribute value
> >>>>> + * @a_name: The attribute name
> >>>>> + * @a_value: The attribute value
> >>>>> + *
> >>>>> + * Sets an attribute to new value
> >>>>> + */
> >>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
> >>>>> +{
> >>>>> +     size_t security_area_size;
> >>>>> +     size_t a_name_size, a_value_size;
> >>>>> +     u16 *buffer = NULL;
> >>>>> +     u16 *start = NULL;
> >>>>> +     int  buffer_size;
> >>>>
> >>>> You have 2 spaces between int and buffer_size here, please drop
> >>>> one.
> >>>>
> >>>>
> >>>>> +     int ret;
> >>>>> +     int instance;
> >>>>> +     char *auth_empty_value = " ";
> >>>>> +
> >>>>> +     mutex_lock(&bioscfg_drv.mutex);
> >>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
> >>>>> +             ret = -ENODEV;
> >>>>> +             goto out_set_attribute;
> >>>>> +     }
> >>>>> +
> >>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
> >>>>> +     if (instance < 0)
> >>>>> +             goto out_set_attribute;
> >>>>> +
> >>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> >>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
> >>>>> +                     auth_empty_value,
> >>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
> >>>>
> >>>> strncpy does not guarantee 0 termination of the destination buffer,
> >>>> please use strscpy.
> >>>>
> >>>>> +
> >>>>> +     a_name_size = calculate_string_buffer(a_name);
> >>>>> +     a_value_size = calculate_string_buffer(a_value);
> >>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> >>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
> >>>>> +
> >>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
> >>>>> +     if (!buffer) {
> >>>>> +             ret = -ENOMEM;
> >>>>> +             goto out_set_attribute;
> >>>>> +     }
> >>>>> +
> >>>>> +     /* build variables to set */
> >>>>> +     start = buffer;
> >>>>> +     start = ascii_to_utf16_unicode(start, a_name);
> >>>>> +     if (!start)
> >>>>> +             goto out_set_attribute;
> >>>>> +
> >>>>> +     start = ascii_to_utf16_unicode(start, a_value);
> >>>>> +     if (!start)
> >>>>> +             goto out_set_attribute;
> >>>>> +
> >>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> >>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> >>>>> +
> >>>>> +
> >>>>> +out_set_attribute:
> >>>>> +     kfree(buffer);
> >>>>> +     mutex_unlock(&bioscfg_drv.mutex);
> >>>>> +     return ret;
> >>>>> +}
> >>>>> +
> >>>>> +/*
> >>>>> + * hp_wmi_perform_query
> >>>>> + *
> >>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
> >>>>> + * write:    The command (enum hp_wmi_command)
> >>>>> + * buffer:   Buffer used as input and/or output
> >>>>> + * insize:   Size of input buffer
> >>>>> + * outsize:  Size of output buffer
> >>>>> + *
> >>>>> + * returns zero on success
> >>>>> + *         an HP WMI query specific error code (which is positive)
> >>>>> + *         -EINVAL if the query was not successful at all
> >>>>> + *         -EINVAL if the output buffer size exceeds buffersize
> >>>>> + *
> >>>>> + * Note: The buffersize must at least be the maximum of the input and output
> >>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
> >>>>> + *       and 128 byte output. The caller would do:
> >>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
> >>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> >>>>> + */
> >>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> >>>>> +{
> >>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> >>>>> +     struct bios_return *bios_return;
> >>>>> +     union acpi_object *obj = NULL;
> >>>>> +     struct bios_args *args = NULL;
> >>>>> +     int mid, actual_insize, actual_outsize;
> >>>>> +     size_t bios_args_size;
> >>>>> +     int ret;
> >>>>> +
> >>>>> +     mid = encode_outsize_for_pvsz(outsize);
> >>>>> +     if (WARN_ON(mid < 0))
> >>>>> +             return mid;
> >>>>> +
> >>>>> +     actual_insize = insize;
> >>>>> +     bios_args_size = struct_size(args, data, insize);
> >>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
> >>>>> +     if (!args)
> >>>>> +             return -ENOMEM;
> >>>>> +
> >>>>> +     input.length = bios_args_size;
> >>>>> +     input.pointer = args;
> >>>>> +
> >>>>> +     args->signature = 0x55434553;
> >>>>> +     args->command = command;
> >>>>> +     args->commandtype = query;
> >>>>> +     args->datasize = insize;
> >>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
> >>>>> +
> >>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> >>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>> +     if (ret)
> >>>>> +             goto out_free;
> >>>>> +
> >>>>> +     obj = output.pointer;
> >>>>> +     if (!obj) {
> >>>>> +             ret = -EINVAL;
> >>>>> +             goto out_free;
> >>>>> +     }
> >>>>> +
> >>>>
> >>>> You need to check the type of obj here before dereferencing
> >>>> obj as if it is a buffer.
> >>>>
> >>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
> >>>>> +     ret = bios_return->return_code;
> >>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>> +     if (ret) {
> >>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> >>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> >>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> >>>>> +             goto out_free;
> >>>>> +     }
> >>>>> +
> >>>>> +     /* Ignore output data of zero size */
> >>>>> +     if (!outsize)
> >>>>> +             goto out_free;
> >>>>> +
> >>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> >>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> >>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> >>>>> +
> >>>>> +out_free:
> >>>>> +     kfree(obj);
> >>>>> +     kfree(args);
> >>>>> +     return ret;
> >>>>> +}
> >>>>> +
> >>>>> +/*
> >>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> >>>>> + *
> >>>>> + * @p:   Unicode buffer address
> >>>>> + * @str: string to convert to unicode
> >>>>> + *
> >>>>> + * Returns a void pointer to the buffer containing unicode string
> >>>>> + */
> >>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> >>>>> +{
> >>>>> +     int len = strlen(str);
> >>>>> +     int ret;
> >>>>> +
> >>>>> +     /*
> >>>>> +      * Add null character when reading an empty string
> >>>>> +      */
> >>>>> +     if (len == 0) {
> >>>>> +             *p++ = 2;
> >>>>> +             *p++ = (u8)0x00;
> >>>>> +             return p;
> >>>>
> >>>> This does not match with calculate_string_buffer() which will
> >>>> return 2 for a 0 length string while you are using 4 bytes here.
> >>>>
> >>>> I guess this may also be why you need to use " " for
> >>>> auth_empty_value above, so as to avoid this bug.
> >>>>
> >>> HP BIOS expects 2 characters when an empty string is being converted
> >>> to u16 hence the reason for returning 2 instead of zero.  This is an
> >>> intended behavior and needed when  allocating a buffer and writing to
> >>> BIOS.
> >>
> >> Right I understand that, it wants 2 characters for the 16 bit length
> >> word, but why not write 0 to that 16 bit length word. Why actually
> >> say the string-buffer length is 2 bytes long / and then write
> >> a 16-bit word with value 0?
> >>
> >> What you are doing now creates a 4 byte buffer like this:
> >>
> >> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
> >>
> >> Why not just create a 2 byte buffer like this:
> >>
> >> u8 buf[2] = { 0x00, 0x00 }
> >>
> >> ?
> >>
> >>
> >> Also I'm wondering why the empty auth string is " " and
> >> not "" ?
> >>
> >>
> >
> > The string returned for an empty string is 4 bytes.  The returned
> > string includes two bytes for the string size in bytes and the
> > remaining bytes are the string.
> > Size =  0x02, 0x00
> > String = 0x00, 0x00
> >
> > All strings return include the string size in bytes followed by the u16 string
>
> Right I understand that, but why is the "String = 0x00, 0x00"
> there ? All the non-0-length strings are not 0 terminated,
> why does the zero length string needs to be specified as length 2
> (1 u16) and then have that u16 be a 0 terminator ?
>
It is a specific format required by BIOS for any zero-length strings.
I don't know the reason why BIOS wants that format.


> Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
> an empty string?
>

I tried during the development process and each time the data is
rejected by BIOS.

> ###
>
> Also you did not answer this separate question:
>
> I'm wondering why the empty auth string is " " and not "" ?
>
That was an oversight.  It should be '""'.  I will make the change
>
> Regards,
>
> Hans
>
>

Hans de Goede Nov. 9, 2022, 8:55 p.m. UTC | #7

Hi,

On 11/9/22 21:52, Jorge Lopez wrote:
> On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <[e-mail]> wrote:
>>
>> Hi,
>>
>> On 11/9/22 21:00, Jorge Lopez wrote:
>>> Hi Hans,
>>>
>>> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On 11/9/22 18:24, Jorge Lopez wrote:
>>>>> HI Hans,
>>>>>
>>>>> Please see questions and comments below.
>>>>>
>>>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
>>>>>>
>>>>>> Hi Jorge,
>>>>>>
>>>>>> Review comments inline.
>>>>>>
>>>>>> On 10/20/22 22:10, Jorge Lopez wrote:
>>>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
>>>>>>> HP Linux kernel drivers.  The driver include a total of 12 files
>>>>>>> broken in several patches.  This is set 1 of 4.
>>>>>>>
>>>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
>>>>>>> the latest sysfs class firmware attributes framework allowing the user
>>>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
>>>>>>> notebooks.
>>>>>>>
>>>>>>> Many features of HP Commercial PC’s can be managed using Windows
>>>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
>>>>>>> Enterprise Management (WBEM) that provides a standards-based interface
>>>>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
>>>>>>> a native Linux solution and the exposed features facilitates the
>>>>>>> migration to Linux environments.
>>>>>>>
>>>>>>> The Linux security features to be provided in hp-bioscfg driver enables
>>>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
>>>>>>> filesystem that can be used by user-mode applications.   The new
>>>>>>> documentation cover features such Secure Platform Management, Sure
>>>>>>> Admin, and Sure Start.  Each section provides security feature
>>>>>>> description and identifies sysfs directories and files exposed by
>>>>>>> the driver.
>>>>>>>
>>>>>>> Many HP Commercial PC’s include a feature called Secure Platform
>>>>>>> Management (SPM), which replaces older password-based BIOS settings
>>>>>>> management with public key cryptography. PC secure product management
>>>>>>> begins when a target system is provisioned with cryptographic keys
>>>>>>> that are used to ensure the integrity of communications between system
>>>>>>> management utilities and the BIOS.
>>>>>>>
>>>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
>>>>>>> and capabilities, many of which are related to security. To prevent
>>>>>>> unauthorized changes to these settings, the system can be configured
>>>>>>> to use a Sure Admin cryptographic signature-based authorization string
>>>>>>> that the BIOS will use to verify authorization to modify the setting.
>>>>>>>
>>>>>>> Signed-off-by: Jorge Lopez <[e-mail]>
>>>>>>>
>>>>>>> ---
>>>>>>> Based on the latest platform-drivers-x86.git/for-next
>>>>>>> ---
>>>>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>>>>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>>>>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>>>>>>>  3 files changed, 1477 insertions(+)
>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
>>>>>>>
>>>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..f0c919bf3ab0
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>> @@ -0,0 +1,285 @@
>>>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>>>> +/*
>>>>>>> + * Functions corresponding to methods under BIOS interface GUID
>>>>>>> + * for use with hp-bioscfg driver.
>>>>>>> + *
>>>>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
>>>>>>> + */
>>>>>>> +
>>>>>>> +#include <linux/wmi.h>
>>>>>>> +#include "bioscfg.h"
>>>>>>> +
>>>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
>>>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
>>>>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * set_attribute() - Update an attribute value
>>>>>>> + * @a_name: The attribute name
>>>>>>> + * @a_value: The attribute value
>>>>>>> + *
>>>>>>> + * Sets an attribute to new value
>>>>>>> + */
>>>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
>>>>>>> +{
>>>>>>> +     size_t security_area_size;
>>>>>>> +     size_t a_name_size, a_value_size;
>>>>>>> +     u16 *buffer = NULL;
>>>>>>> +     u16 *start = NULL;
>>>>>>> +     int  buffer_size;
>>>>>>
>>>>>> You have 2 spaces between int and buffer_size here, please drop
>>>>>> one.
>>>>>>
>>>>>>
>>>>>>> +     int ret;
>>>>>>> +     int instance;
>>>>>>> +     char *auth_empty_value = " ";
>>>>>>> +
>>>>>>> +     mutex_lock(&bioscfg_drv.mutex);
>>>>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
>>>>>>> +             ret = -ENODEV;
>>>>>>> +             goto out_set_attribute;
>>>>>>> +     }
>>>>>>> +
>>>>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
>>>>>>> +     if (instance < 0)
>>>>>>> +             goto out_set_attribute;
>>>>>>> +
>>>>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
>>>>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
>>>>>>> +                     auth_empty_value,
>>>>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
>>>>>>
>>>>>> strncpy does not guarantee 0 termination of the destination buffer,
>>>>>> please use strscpy.
>>>>>>
>>>>>>> +
>>>>>>> +     a_name_size = calculate_string_buffer(a_name);
>>>>>>> +     a_value_size = calculate_string_buffer(a_value);
>>>>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
>>>>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
>>>>>>> +
>>>>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
>>>>>>> +     if (!buffer) {
>>>>>>> +             ret = -ENOMEM;
>>>>>>> +             goto out_set_attribute;
>>>>>>> +     }
>>>>>>> +
>>>>>>> +     /* build variables to set */
>>>>>>> +     start = buffer;
>>>>>>> +     start = ascii_to_utf16_unicode(start, a_name);
>>>>>>> +     if (!start)
>>>>>>> +             goto out_set_attribute;
>>>>>>> +
>>>>>>> +     start = ascii_to_utf16_unicode(start, a_value);
>>>>>>> +     if (!start)
>>>>>>> +             goto out_set_attribute;
>>>>>>> +
>>>>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
>>>>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
>>>>>>> +
>>>>>>> +
>>>>>>> +out_set_attribute:
>>>>>>> +     kfree(buffer);
>>>>>>> +     mutex_unlock(&bioscfg_drv.mutex);
>>>>>>> +     return ret;
>>>>>>> +}
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * hp_wmi_perform_query
>>>>>>> + *
>>>>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
>>>>>>> + * write:    The command (enum hp_wmi_command)
>>>>>>> + * buffer:   Buffer used as input and/or output
>>>>>>> + * insize:   Size of input buffer
>>>>>>> + * outsize:  Size of output buffer
>>>>>>> + *
>>>>>>> + * returns zero on success
>>>>>>> + *         an HP WMI query specific error code (which is positive)
>>>>>>> + *         -EINVAL if the query was not successful at all
>>>>>>> + *         -EINVAL if the output buffer size exceeds buffersize
>>>>>>> + *
>>>>>>> + * Note: The buffersize must at least be the maximum of the input and output
>>>>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
>>>>>>> + *       and 128 byte output. The caller would do:
>>>>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
>>>>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
>>>>>>> + */
>>>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
>>>>>>> +{
>>>>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
>>>>>>> +     struct bios_return *bios_return;
>>>>>>> +     union acpi_object *obj = NULL;
>>>>>>> +     struct bios_args *args = NULL;
>>>>>>> +     int mid, actual_insize, actual_outsize;
>>>>>>> +     size_t bios_args_size;
>>>>>>> +     int ret;
>>>>>>> +
>>>>>>> +     mid = encode_outsize_for_pvsz(outsize);
>>>>>>> +     if (WARN_ON(mid < 0))
>>>>>>> +             return mid;
>>>>>>> +
>>>>>>> +     actual_insize = insize;
>>>>>>> +     bios_args_size = struct_size(args, data, insize);
>>>>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
>>>>>>> +     if (!args)
>>>>>>> +             return -ENOMEM;
>>>>>>> +
>>>>>>> +     input.length = bios_args_size;
>>>>>>> +     input.pointer = args;
>>>>>>> +
>>>>>>> +     args->signature = 0x55434553;
>>>>>>> +     args->command = command;
>>>>>>> +     args->commandtype = query;
>>>>>>> +     args->datasize = insize;
>>>>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
>>>>>>> +
>>>>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>>>> +     if (ret)
>>>>>>> +             goto out_free;
>>>>>>> +
>>>>>>> +     obj = output.pointer;
>>>>>>> +     if (!obj) {
>>>>>>> +             ret = -EINVAL;
>>>>>>> +             goto out_free;
>>>>>>> +     }
>>>>>>> +
>>>>>>
>>>>>> You need to check the type of obj here before dereferencing
>>>>>> obj as if it is a buffer.
>>>>>>
>>>>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
>>>>>>> +     ret = bios_return->return_code;
>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>>>> +     if (ret) {
>>>>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
>>>>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
>>>>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
>>>>>>> +             goto out_free;
>>>>>>> +     }
>>>>>>> +
>>>>>>> +     /* Ignore output data of zero size */
>>>>>>> +     if (!outsize)
>>>>>>> +             goto out_free;
>>>>>>> +
>>>>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
>>>>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
>>>>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
>>>>>>> +
>>>>>>> +out_free:
>>>>>>> +     kfree(obj);
>>>>>>> +     kfree(args);
>>>>>>> +     return ret;
>>>>>>> +}
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
>>>>>>> + *
>>>>>>> + * @p:   Unicode buffer address
>>>>>>> + * @str: string to convert to unicode
>>>>>>> + *
>>>>>>> + * Returns a void pointer to the buffer containing unicode string
>>>>>>> + */
>>>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
>>>>>>> +{
>>>>>>> +     int len = strlen(str);
>>>>>>> +     int ret;
>>>>>>> +
>>>>>>> +     /*
>>>>>>> +      * Add null character when reading an empty string
>>>>>>> +      */
>>>>>>> +     if (len == 0) {
>>>>>>> +             *p++ = 2;
>>>>>>> +             *p++ = (u8)0x00;
>>>>>>> +             return p;
>>>>>>
>>>>>> This does not match with calculate_string_buffer() which will
>>>>>> return 2 for a 0 length string while you are using 4 bytes here.
>>>>>>
>>>>>> I guess this may also be why you need to use " " for
>>>>>> auth_empty_value above, so as to avoid this bug.
>>>>>>
>>>>> HP BIOS expects 2 characters when an empty string is being converted
>>>>> to u16 hence the reason for returning 2 instead of zero.  This is an
>>>>> intended behavior and needed when  allocating a buffer and writing to
>>>>> BIOS.
>>>>
>>>> Right I understand that, it wants 2 characters for the 16 bit length
>>>> word, but why not write 0 to that 16 bit length word. Why actually
>>>> say the string-buffer length is 2 bytes long / and then write
>>>> a 16-bit word with value 0?
>>>>
>>>> What you are doing now creates a 4 byte buffer like this:
>>>>
>>>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
>>>>
>>>> Why not just create a 2 byte buffer like this:
>>>>
>>>> u8 buf[2] = { 0x00, 0x00 }
>>>>
>>>> ?
>>>>
>>>>
>>>> Also I'm wondering why the empty auth string is " " and
>>>> not "" ?
>>>>
>>>>
>>>
>>> The string returned for an empty string is 4 bytes.  The returned
>>> string includes two bytes for the string size in bytes and the
>>> remaining bytes are the string.
>>> Size =  0x02, 0x00
>>> String = 0x00, 0x00
>>>
>>> All strings return include the string size in bytes followed by the u16 string
>>
>> Right I understand that, but why is the "String = 0x00, 0x00"
>> there ? All the non-0-length strings are not 0 terminated,
>> why does the zero length string needs to be specified as length 2
>> (1 u16) and then have that u16 be a 0 terminator ?
>>
> It is a specific format required by BIOS for any zero-length strings.
> I don't know the reason why BIOS wants that format.
> 
> 
>> Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
>> an empty string?
>>
> 
> I tried during the development process and each time the data is
> rejected by BIOS.

Ok, well in that case you are going to need your own
ascii_to_utf16_unicode() to handle the weird case for the
0 sized string, so no need to move the dell-wmi-sysman versions
to the shared wmi code.

But please do start with a copy of the Dell function and then
add the special case for the 0 len string, since the original
version above does not properly handle errors.

Also this means you need to update the hp calculate_string_buffer()
copy to properly return 4 rather then 2 for the bufsize for
a 0 length string.

Regards,

Hans

Jorge Lopez Nov. 9, 2022, 9:04 p.m. UTC | #8

On Wed, Nov 9, 2022 at 2:55 PM Hans de Goede <[e-mail]> wrote:
>
> Hi,
>
> On 11/9/22 21:52, Jorge Lopez wrote:
> > On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <[e-mail]> wrote:
> >>
> >> Hi,
> >>
> >> On 11/9/22 21:00, Jorge Lopez wrote:
> >>> Hi Hans,
> >>>
> >>> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
> >>>>
> >>>> Hi,
> >>>>
> >>>> On 11/9/22 18:24, Jorge Lopez wrote:
> >>>>> HI Hans,
> >>>>>
> >>>>> Please see questions and comments below.
> >>>>>
> >>>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
> >>>>>>
> >>>>>> Hi Jorge,
> >>>>>>
> >>>>>> Review comments inline.
> >>>>>>
> >>>>>> On 10/20/22 22:10, Jorge Lopez wrote:
> >>>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
> >>>>>>> HP Linux kernel drivers.  The driver include a total of 12 files
> >>>>>>> broken in several patches.  This is set 1 of 4.
> >>>>>>>
> >>>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
> >>>>>>> the latest sysfs class firmware attributes framework allowing the user
> >>>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
> >>>>>>> notebooks.
> >>>>>>>
> >>>>>>> Many features of HP Commercial PC’s can be managed using Windows
> >>>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> >>>>>>> Enterprise Management (WBEM) that provides a standards-based interface
> >>>>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
> >>>>>>> a native Linux solution and the exposed features facilitates the
> >>>>>>> migration to Linux environments.
> >>>>>>>
> >>>>>>> The Linux security features to be provided in hp-bioscfg driver enables
> >>>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
> >>>>>>> filesystem that can be used by user-mode applications.   The new
> >>>>>>> documentation cover features such Secure Platform Management, Sure
> >>>>>>> Admin, and Sure Start.  Each section provides security feature
> >>>>>>> description and identifies sysfs directories and files exposed by
> >>>>>>> the driver.
> >>>>>>>
> >>>>>>> Many HP Commercial PC’s include a feature called Secure Platform
> >>>>>>> Management (SPM), which replaces older password-based BIOS settings
> >>>>>>> management with public key cryptography. PC secure product management
> >>>>>>> begins when a target system is provisioned with cryptographic keys
> >>>>>>> that are used to ensure the integrity of communications between system
> >>>>>>> management utilities and the BIOS.
> >>>>>>>
> >>>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
> >>>>>>> and capabilities, many of which are related to security. To prevent
> >>>>>>> unauthorized changes to these settings, the system can be configured
> >>>>>>> to use a Sure Admin cryptographic signature-based authorization string
> >>>>>>> that the BIOS will use to verify authorization to modify the setting.
> >>>>>>>
> >>>>>>> Signed-off-by: Jorge Lopez <[e-mail]>
> >>>>>>>
> >>>>>>> ---
> >>>>>>> Based on the latest platform-drivers-x86.git/for-next
> >>>>>>> ---
> >>>>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
> >>>>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
> >>>>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
> >>>>>>>  3 files changed, 1477 insertions(+)
> >>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >>>>>>>
> >>>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>> new file mode 100644
> >>>>>>> index 000000000000..f0c919bf3ab0
> >>>>>>> --- /dev/null
> >>>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>> @@ -0,0 +1,285 @@
> >>>>>>> +// SPDX-License-Identifier: GPL-2.0
> >>>>>>> +/*
> >>>>>>> + * Functions corresponding to methods under BIOS interface GUID
> >>>>>>> + * for use with hp-bioscfg driver.
> >>>>>>> + *
> >>>>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> >>>>>>> + */
> >>>>>>> +
> >>>>>>> +#include <linux/wmi.h>
> >>>>>>> +#include "bioscfg.h"
> >>>>>>> +
> >>>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> >>>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
> >>>>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
> >>>>>>> +
> >>>>>>> +/*
> >>>>>>> + * set_attribute() - Update an attribute value
> >>>>>>> + * @a_name: The attribute name
> >>>>>>> + * @a_value: The attribute value
> >>>>>>> + *
> >>>>>>> + * Sets an attribute to new value
> >>>>>>> + */
> >>>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
> >>>>>>> +{
> >>>>>>> +     size_t security_area_size;
> >>>>>>> +     size_t a_name_size, a_value_size;
> >>>>>>> +     u16 *buffer = NULL;
> >>>>>>> +     u16 *start = NULL;
> >>>>>>> +     int  buffer_size;
> >>>>>>
> >>>>>> You have 2 spaces between int and buffer_size here, please drop
> >>>>>> one.
> >>>>>>
> >>>>>>
> >>>>>>> +     int ret;
> >>>>>>> +     int instance;
> >>>>>>> +     char *auth_empty_value = " ";
> >>>>>>> +
> >>>>>>> +     mutex_lock(&bioscfg_drv.mutex);
> >>>>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
> >>>>>>> +             ret = -ENODEV;
> >>>>>>> +             goto out_set_attribute;
> >>>>>>> +     }
> >>>>>>> +
> >>>>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
> >>>>>>> +     if (instance < 0)
> >>>>>>> +             goto out_set_attribute;
> >>>>>>> +
> >>>>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> >>>>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
> >>>>>>> +                     auth_empty_value,
> >>>>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
> >>>>>>
> >>>>>> strncpy does not guarantee 0 termination of the destination buffer,
> >>>>>> please use strscpy.
> >>>>>>
> >>>>>>> +
> >>>>>>> +     a_name_size = calculate_string_buffer(a_name);
> >>>>>>> +     a_value_size = calculate_string_buffer(a_value);
> >>>>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> >>>>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
> >>>>>>> +
> >>>>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
> >>>>>>> +     if (!buffer) {
> >>>>>>> +             ret = -ENOMEM;
> >>>>>>> +             goto out_set_attribute;
> >>>>>>> +     }
> >>>>>>> +
> >>>>>>> +     /* build variables to set */
> >>>>>>> +     start = buffer;
> >>>>>>> +     start = ascii_to_utf16_unicode(start, a_name);
> >>>>>>> +     if (!start)
> >>>>>>> +             goto out_set_attribute;
> >>>>>>> +
> >>>>>>> +     start = ascii_to_utf16_unicode(start, a_value);
> >>>>>>> +     if (!start)
> >>>>>>> +             goto out_set_attribute;
> >>>>>>> +
> >>>>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> >>>>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> >>>>>>> +
> >>>>>>> +
> >>>>>>> +out_set_attribute:
> >>>>>>> +     kfree(buffer);
> >>>>>>> +     mutex_unlock(&bioscfg_drv.mutex);
> >>>>>>> +     return ret;
> >>>>>>> +}
> >>>>>>> +
> >>>>>>> +/*
> >>>>>>> + * hp_wmi_perform_query
> >>>>>>> + *
> >>>>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
> >>>>>>> + * write:    The command (enum hp_wmi_command)
> >>>>>>> + * buffer:   Buffer used as input and/or output
> >>>>>>> + * insize:   Size of input buffer
> >>>>>>> + * outsize:  Size of output buffer
> >>>>>>> + *
> >>>>>>> + * returns zero on success
> >>>>>>> + *         an HP WMI query specific error code (which is positive)
> >>>>>>> + *         -EINVAL if the query was not successful at all
> >>>>>>> + *         -EINVAL if the output buffer size exceeds buffersize
> >>>>>>> + *
> >>>>>>> + * Note: The buffersize must at least be the maximum of the input and output
> >>>>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
> >>>>>>> + *       and 128 byte output. The caller would do:
> >>>>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
> >>>>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> >>>>>>> + */
> >>>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> >>>>>>> +{
> >>>>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> >>>>>>> +     struct bios_return *bios_return;
> >>>>>>> +     union acpi_object *obj = NULL;
> >>>>>>> +     struct bios_args *args = NULL;
> >>>>>>> +     int mid, actual_insize, actual_outsize;
> >>>>>>> +     size_t bios_args_size;
> >>>>>>> +     int ret;
> >>>>>>> +
> >>>>>>> +     mid = encode_outsize_for_pvsz(outsize);
> >>>>>>> +     if (WARN_ON(mid < 0))
> >>>>>>> +             return mid;
> >>>>>>> +
> >>>>>>> +     actual_insize = insize;
> >>>>>>> +     bios_args_size = struct_size(args, data, insize);
> >>>>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
> >>>>>>> +     if (!args)
> >>>>>>> +             return -ENOMEM;
> >>>>>>> +
> >>>>>>> +     input.length = bios_args_size;
> >>>>>>> +     input.pointer = args;
> >>>>>>> +
> >>>>>>> +     args->signature = 0x55434553;
> >>>>>>> +     args->command = command;
> >>>>>>> +     args->commandtype = query;
> >>>>>>> +     args->datasize = insize;
> >>>>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
> >>>>>>> +
> >>>>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> >>>>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>>>> +     if (ret)
> >>>>>>> +             goto out_free;
> >>>>>>> +
> >>>>>>> +     obj = output.pointer;
> >>>>>>> +     if (!obj) {
> >>>>>>> +             ret = -EINVAL;
> >>>>>>> +             goto out_free;
> >>>>>>> +     }
> >>>>>>> +
> >>>>>>
> >>>>>> You need to check the type of obj here before dereferencing
> >>>>>> obj as if it is a buffer.
> >>>>>>
> >>>>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
> >>>>>>> +     ret = bios_return->return_code;
> >>>>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>>>> +     if (ret) {
> >>>>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> >>>>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> >>>>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> >>>>>>> +             goto out_free;
> >>>>>>> +     }
> >>>>>>> +
> >>>>>>> +     /* Ignore output data of zero size */
> >>>>>>> +     if (!outsize)
> >>>>>>> +             goto out_free;
> >>>>>>> +
> >>>>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> >>>>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> >>>>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> >>>>>>> +
> >>>>>>> +out_free:
> >>>>>>> +     kfree(obj);
> >>>>>>> +     kfree(args);
> >>>>>>> +     return ret;
> >>>>>>> +}
> >>>>>>> +
> >>>>>>> +/*
> >>>>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> >>>>>>> + *
> >>>>>>> + * @p:   Unicode buffer address
> >>>>>>> + * @str: string to convert to unicode
> >>>>>>> + *
> >>>>>>> + * Returns a void pointer to the buffer containing unicode string
> >>>>>>> + */
> >>>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> >>>>>>> +{
> >>>>>>> +     int len = strlen(str);
> >>>>>>> +     int ret;
> >>>>>>> +
> >>>>>>> +     /*
> >>>>>>> +      * Add null character when reading an empty string
> >>>>>>> +      */
> >>>>>>> +     if (len == 0) {
> >>>>>>> +             *p++ = 2;
> >>>>>>> +             *p++ = (u8)0x00;
> >>>>>>> +             return p;
> >>>>>>
> >>>>>> This does not match with calculate_string_buffer() which will
> >>>>>> return 2 for a 0 length string while you are using 4 bytes here.
> >>>>>>
> >>>>>> I guess this may also be why you need to use " " for
> >>>>>> auth_empty_value above, so as to avoid this bug.
> >>>>>>
> >>>>> HP BIOS expects 2 characters when an empty string is being converted
> >>>>> to u16 hence the reason for returning 2 instead of zero.  This is an
> >>>>> intended behavior and needed when  allocating a buffer and writing to
> >>>>> BIOS.
> >>>>
> >>>> Right I understand that, it wants 2 characters for the 16 bit length
> >>>> word, but why not write 0 to that 16 bit length word. Why actually
> >>>> say the string-buffer length is 2 bytes long / and then write
> >>>> a 16-bit word with value 0?
> >>>>
> >>>> What you are doing now creates a 4 byte buffer like this:
> >>>>
> >>>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
> >>>>
> >>>> Why not just create a 2 byte buffer like this:
> >>>>
> >>>> u8 buf[2] = { 0x00, 0x00 }
> >>>>
> >>>> ?
> >>>>
> >>>>
> >>>> Also I'm wondering why the empty auth string is " " and
> >>>> not "" ?
> >>>>
> >>>>
> >>>
> >>> The string returned for an empty string is 4 bytes.  The returned
> >>> string includes two bytes for the string size in bytes and the
> >>> remaining bytes are the string.
> >>> Size =  0x02, 0x00
> >>> String = 0x00, 0x00
> >>>
> >>> All strings return include the string size in bytes followed by the u16 string
> >>
> >> Right I understand that, but why is the "String = 0x00, 0x00"
> >> there ? All the non-0-length strings are not 0 terminated,
> >> why does the zero length string needs to be specified as length 2
> >> (1 u16) and then have that u16 be a 0 terminator ?
> >>
> > It is a specific format required by BIOS for any zero-length strings.
> > I don't know the reason why BIOS wants that format.
> >
> >
> >> Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
> >> an empty string?
> >>
> >
> > I tried during the development process and each time the data is
> > rejected by BIOS.
>
> Ok, well in that case you are going to need your own
> ascii_to_utf16_unicode() to handle the weird case for the
> 0 sized string, so no need to move the dell-wmi-sysman versions
> to the shared wmi code.
>
> But please do start with a copy of the Dell function and then
> add the special case for the 0 len string, since the original
> version above does not properly handle errors.
>
> Also this means you need to update the hp calculate_string_buffer()
> copy to properly return 4 rather then 2 for the bufsize for
> a 0 length string.
>

I will do so. Thanks.
BTW, changes requested for sysman.c will require changes to two other
DELL source files;
biosattr-interface.c and passwordattr-interface.c.
All I can do is to verify it compiles ok.

> Regards,
>
> Hans
>
>

Hans de Goede Nov. 9, 2022, 9:11 p.m. UTC | #9

Hi,

On 11/9/22 22:04, Jorge Lopez wrote:
> On Wed, Nov 9, 2022 at 2:55 PM Hans de Goede <[e-mail]> wrote:
>>
>> Hi,
>>
>> On 11/9/22 21:52, Jorge Lopez wrote:
>>> On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <[e-mail]> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On 11/9/22 21:00, Jorge Lopez wrote:
>>>>> Hi Hans,
>>>>>
>>>>> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On 11/9/22 18:24, Jorge Lopez wrote:
>>>>>>> HI Hans,
>>>>>>>
>>>>>>> Please see questions and comments below.
>>>>>>>
>>>>>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
>>>>>>>>
>>>>>>>> Hi Jorge,
>>>>>>>>
>>>>>>>> Review comments inline.
>>>>>>>>
>>>>>>>> On 10/20/22 22:10, Jorge Lopez wrote:
>>>>>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
>>>>>>>>> HP Linux kernel drivers.  The driver include a total of 12 files
>>>>>>>>> broken in several patches.  This is set 1 of 4.
>>>>>>>>>
>>>>>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
>>>>>>>>> the latest sysfs class firmware attributes framework allowing the user
>>>>>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
>>>>>>>>> notebooks.
>>>>>>>>>
>>>>>>>>> Many features of HP Commercial PC’s can be managed using Windows
>>>>>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
>>>>>>>>> Enterprise Management (WBEM) that provides a standards-based interface
>>>>>>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
>>>>>>>>> a native Linux solution and the exposed features facilitates the
>>>>>>>>> migration to Linux environments.
>>>>>>>>>
>>>>>>>>> The Linux security features to be provided in hp-bioscfg driver enables
>>>>>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
>>>>>>>>> filesystem that can be used by user-mode applications.   The new
>>>>>>>>> documentation cover features such Secure Platform Management, Sure
>>>>>>>>> Admin, and Sure Start.  Each section provides security feature
>>>>>>>>> description and identifies sysfs directories and files exposed by
>>>>>>>>> the driver.
>>>>>>>>>
>>>>>>>>> Many HP Commercial PC’s include a feature called Secure Platform
>>>>>>>>> Management (SPM), which replaces older password-based BIOS settings
>>>>>>>>> management with public key cryptography. PC secure product management
>>>>>>>>> begins when a target system is provisioned with cryptographic keys
>>>>>>>>> that are used to ensure the integrity of communications between system
>>>>>>>>> management utilities and the BIOS.
>>>>>>>>>
>>>>>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
>>>>>>>>> and capabilities, many of which are related to security. To prevent
>>>>>>>>> unauthorized changes to these settings, the system can be configured
>>>>>>>>> to use a Sure Admin cryptographic signature-based authorization string
>>>>>>>>> that the BIOS will use to verify authorization to modify the setting.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Jorge Lopez <[e-mail]>
>>>>>>>>>
>>>>>>>>> ---
>>>>>>>>> Based on the latest platform-drivers-x86.git/for-next
>>>>>>>>> ---
>>>>>>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
>>>>>>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
>>>>>>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
>>>>>>>>>  3 files changed, 1477 insertions(+)
>>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
>>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>>>> new file mode 100644
>>>>>>>>> index 000000000000..f0c919bf3ab0
>>>>>>>>> --- /dev/null
>>>>>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
>>>>>>>>> @@ -0,0 +1,285 @@
>>>>>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>>>>>> +/*
>>>>>>>>> + * Functions corresponding to methods under BIOS interface GUID
>>>>>>>>> + * for use with hp-bioscfg driver.
>>>>>>>>> + *
>>>>>>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
>>>>>>>>> + */
>>>>>>>>> +
>>>>>>>>> +#include <linux/wmi.h>
>>>>>>>>> +#include "bioscfg.h"
>>>>>>>>> +
>>>>>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
>>>>>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
>>>>>>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
>>>>>>>>> +
>>>>>>>>> +/*
>>>>>>>>> + * set_attribute() - Update an attribute value
>>>>>>>>> + * @a_name: The attribute name
>>>>>>>>> + * @a_value: The attribute value
>>>>>>>>> + *
>>>>>>>>> + * Sets an attribute to new value
>>>>>>>>> + */
>>>>>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
>>>>>>>>> +{
>>>>>>>>> +     size_t security_area_size;
>>>>>>>>> +     size_t a_name_size, a_value_size;
>>>>>>>>> +     u16 *buffer = NULL;
>>>>>>>>> +     u16 *start = NULL;
>>>>>>>>> +     int  buffer_size;
>>>>>>>>
>>>>>>>> You have 2 spaces between int and buffer_size here, please drop
>>>>>>>> one.
>>>>>>>>
>>>>>>>>
>>>>>>>>> +     int ret;
>>>>>>>>> +     int instance;
>>>>>>>>> +     char *auth_empty_value = " ";
>>>>>>>>> +
>>>>>>>>> +     mutex_lock(&bioscfg_drv.mutex);
>>>>>>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
>>>>>>>>> +             ret = -ENODEV;
>>>>>>>>> +             goto out_set_attribute;
>>>>>>>>> +     }
>>>>>>>>> +
>>>>>>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
>>>>>>>>> +     if (instance < 0)
>>>>>>>>> +             goto out_set_attribute;
>>>>>>>>> +
>>>>>>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
>>>>>>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
>>>>>>>>> +                     auth_empty_value,
>>>>>>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
>>>>>>>>
>>>>>>>> strncpy does not guarantee 0 termination of the destination buffer,
>>>>>>>> please use strscpy.
>>>>>>>>
>>>>>>>>> +
>>>>>>>>> +     a_name_size = calculate_string_buffer(a_name);
>>>>>>>>> +     a_value_size = calculate_string_buffer(a_value);
>>>>>>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
>>>>>>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
>>>>>>>>> +
>>>>>>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
>>>>>>>>> +     if (!buffer) {
>>>>>>>>> +             ret = -ENOMEM;
>>>>>>>>> +             goto out_set_attribute;
>>>>>>>>> +     }
>>>>>>>>> +
>>>>>>>>> +     /* build variables to set */
>>>>>>>>> +     start = buffer;
>>>>>>>>> +     start = ascii_to_utf16_unicode(start, a_name);
>>>>>>>>> +     if (!start)
>>>>>>>>> +             goto out_set_attribute;
>>>>>>>>> +
>>>>>>>>> +     start = ascii_to_utf16_unicode(start, a_value);
>>>>>>>>> +     if (!start)
>>>>>>>>> +             goto out_set_attribute;
>>>>>>>>> +
>>>>>>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
>>>>>>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
>>>>>>>>> +
>>>>>>>>> +
>>>>>>>>> +out_set_attribute:
>>>>>>>>> +     kfree(buffer);
>>>>>>>>> +     mutex_unlock(&bioscfg_drv.mutex);
>>>>>>>>> +     return ret;
>>>>>>>>> +}
>>>>>>>>> +
>>>>>>>>> +/*
>>>>>>>>> + * hp_wmi_perform_query
>>>>>>>>> + *
>>>>>>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
>>>>>>>>> + * write:    The command (enum hp_wmi_command)
>>>>>>>>> + * buffer:   Buffer used as input and/or output
>>>>>>>>> + * insize:   Size of input buffer
>>>>>>>>> + * outsize:  Size of output buffer
>>>>>>>>> + *
>>>>>>>>> + * returns zero on success
>>>>>>>>> + *         an HP WMI query specific error code (which is positive)
>>>>>>>>> + *         -EINVAL if the query was not successful at all
>>>>>>>>> + *         -EINVAL if the output buffer size exceeds buffersize
>>>>>>>>> + *
>>>>>>>>> + * Note: The buffersize must at least be the maximum of the input and output
>>>>>>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
>>>>>>>>> + *       and 128 byte output. The caller would do:
>>>>>>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
>>>>>>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
>>>>>>>>> + */
>>>>>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
>>>>>>>>> +{
>>>>>>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
>>>>>>>>> +     struct bios_return *bios_return;
>>>>>>>>> +     union acpi_object *obj = NULL;
>>>>>>>>> +     struct bios_args *args = NULL;
>>>>>>>>> +     int mid, actual_insize, actual_outsize;
>>>>>>>>> +     size_t bios_args_size;
>>>>>>>>> +     int ret;
>>>>>>>>> +
>>>>>>>>> +     mid = encode_outsize_for_pvsz(outsize);
>>>>>>>>> +     if (WARN_ON(mid < 0))
>>>>>>>>> +             return mid;
>>>>>>>>> +
>>>>>>>>> +     actual_insize = insize;
>>>>>>>>> +     bios_args_size = struct_size(args, data, insize);
>>>>>>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
>>>>>>>>> +     if (!args)
>>>>>>>>> +             return -ENOMEM;
>>>>>>>>> +
>>>>>>>>> +     input.length = bios_args_size;
>>>>>>>>> +     input.pointer = args;
>>>>>>>>> +
>>>>>>>>> +     args->signature = 0x55434553;
>>>>>>>>> +     args->command = command;
>>>>>>>>> +     args->commandtype = query;
>>>>>>>>> +     args->datasize = insize;
>>>>>>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
>>>>>>>>> +
>>>>>>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
>>>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>>>>>> +     if (ret)
>>>>>>>>> +             goto out_free;
>>>>>>>>> +
>>>>>>>>> +     obj = output.pointer;
>>>>>>>>> +     if (!obj) {
>>>>>>>>> +             ret = -EINVAL;
>>>>>>>>> +             goto out_free;
>>>>>>>>> +     }
>>>>>>>>> +
>>>>>>>>
>>>>>>>> You need to check the type of obj here before dereferencing
>>>>>>>> obj as if it is a buffer.
>>>>>>>>
>>>>>>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
>>>>>>>>> +     ret = bios_return->return_code;
>>>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
>>>>>>>>> +     if (ret) {
>>>>>>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
>>>>>>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
>>>>>>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
>>>>>>>>> +             goto out_free;
>>>>>>>>> +     }
>>>>>>>>> +
>>>>>>>>> +     /* Ignore output data of zero size */
>>>>>>>>> +     if (!outsize)
>>>>>>>>> +             goto out_free;
>>>>>>>>> +
>>>>>>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
>>>>>>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
>>>>>>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
>>>>>>>>> +
>>>>>>>>> +out_free:
>>>>>>>>> +     kfree(obj);
>>>>>>>>> +     kfree(args);
>>>>>>>>> +     return ret;
>>>>>>>>> +}
>>>>>>>>> +
>>>>>>>>> +/*
>>>>>>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
>>>>>>>>> + *
>>>>>>>>> + * @p:   Unicode buffer address
>>>>>>>>> + * @str: string to convert to unicode
>>>>>>>>> + *
>>>>>>>>> + * Returns a void pointer to the buffer containing unicode string
>>>>>>>>> + */
>>>>>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
>>>>>>>>> +{
>>>>>>>>> +     int len = strlen(str);
>>>>>>>>> +     int ret;
>>>>>>>>> +
>>>>>>>>> +     /*
>>>>>>>>> +      * Add null character when reading an empty string
>>>>>>>>> +      */
>>>>>>>>> +     if (len == 0) {
>>>>>>>>> +             *p++ = 2;
>>>>>>>>> +             *p++ = (u8)0x00;
>>>>>>>>> +             return p;
>>>>>>>>
>>>>>>>> This does not match with calculate_string_buffer() which will
>>>>>>>> return 2 for a 0 length string while you are using 4 bytes here.
>>>>>>>>
>>>>>>>> I guess this may also be why you need to use " " for
>>>>>>>> auth_empty_value above, so as to avoid this bug.
>>>>>>>>
>>>>>>> HP BIOS expects 2 characters when an empty string is being converted
>>>>>>> to u16 hence the reason for returning 2 instead of zero.  This is an
>>>>>>> intended behavior and needed when  allocating a buffer and writing to
>>>>>>> BIOS.
>>>>>>
>>>>>> Right I understand that, it wants 2 characters for the 16 bit length
>>>>>> word, but why not write 0 to that 16 bit length word. Why actually
>>>>>> say the string-buffer length is 2 bytes long / and then write
>>>>>> a 16-bit word with value 0?
>>>>>>
>>>>>> What you are doing now creates a 4 byte buffer like this:
>>>>>>
>>>>>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
>>>>>>
>>>>>> Why not just create a 2 byte buffer like this:
>>>>>>
>>>>>> u8 buf[2] = { 0x00, 0x00 }
>>>>>>
>>>>>> ?
>>>>>>
>>>>>>
>>>>>> Also I'm wondering why the empty auth string is " " and
>>>>>> not "" ?
>>>>>>
>>>>>>
>>>>>
>>>>> The string returned for an empty string is 4 bytes.  The returned
>>>>> string includes two bytes for the string size in bytes and the
>>>>> remaining bytes are the string.
>>>>> Size =  0x02, 0x00
>>>>> String = 0x00, 0x00
>>>>>
>>>>> All strings return include the string size in bytes followed by the u16 string
>>>>
>>>> Right I understand that, but why is the "String = 0x00, 0x00"
>>>> there ? All the non-0-length strings are not 0 terminated,
>>>> why does the zero length string needs to be specified as length 2
>>>> (1 u16) and then have that u16 be a 0 terminator ?
>>>>
>>> It is a specific format required by BIOS for any zero-length strings.
>>> I don't know the reason why BIOS wants that format.
>>>
>>>
>>>> Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
>>>> an empty string?
>>>>
>>>
>>> I tried during the development process and each time the data is
>>> rejected by BIOS.
>>
>> Ok, well in that case you are going to need your own
>> ascii_to_utf16_unicode() to handle the weird case for the
>> 0 sized string, so no need to move the dell-wmi-sysman versions
>> to the shared wmi code.
>>
>> But please do start with a copy of the Dell function and then
>> add the special case for the 0 len string, since the original
>> version above does not properly handle errors.
>>
>> Also this means you need to update the hp calculate_string_buffer()
>> copy to properly return 4 rather then 2 for the bufsize for
>> a 0 length string.
>>
> 
> I will do so. Thanks.
> BTW, changes requested for sysman.c will require changes to two other
> DELL source files;
> biosattr-interface.c and passwordattr-interface.c.
> All I can do is to verify it compiles ok.

Note that since you now need a special version to deal
with the 0 length string weirdness, you can just make
a private copy of the dell functions into the hp code
and then modify that to add the special case for the
0 length strings.

So there is no longer a need to move the dell versions
out into wmi.c since the hp code will need a modified
version anyways (so the code cannot be shared).

Regards,

Hans

Jorge Lopez Nov. 9, 2022, 9:26 p.m. UTC | #10

On Wed, Nov 9, 2022 at 3:11 PM Hans de Goede <[e-mail]> wrote:
>
> Hi,
>
> On 11/9/22 22:04, Jorge Lopez wrote:
> > On Wed, Nov 9, 2022 at 2:55 PM Hans de Goede <[e-mail]> wrote:
> >>
> >> Hi,
> >>
> >> On 11/9/22 21:52, Jorge Lopez wrote:
> >>> On Wed, Nov 9, 2022 at 2:05 PM Hans de Goede <[e-mail]> wrote:
> >>>>
> >>>> Hi,
> >>>>
> >>>> On 11/9/22 21:00, Jorge Lopez wrote:
> >>>>> Hi Hans,
> >>>>>
> >>>>> On Wed, Nov 9, 2022 at 12:10 PM Hans de Goede <[e-mail]> wrote:
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> On 11/9/22 18:24, Jorge Lopez wrote:
> >>>>>>> HI Hans,
> >>>>>>>
> >>>>>>> Please see questions and comments below.
> >>>>>>>
> >>>>>>> On Tue, Nov 8, 2022 at 8:51 AM Hans de Goede <[e-mail]> wrote:
> >>>>>>>>
> >>>>>>>> Hi Jorge,
> >>>>>>>>
> >>>>>>>> Review comments inline.
> >>>>>>>>
> >>>>>>>> On 10/20/22 22:10, Jorge Lopez wrote:
> >>>>>>>>> The purpose for this patch is submit HP BIOSCFG driver to be list of
> >>>>>>>>> HP Linux kernel drivers.  The driver include a total of 12 files
> >>>>>>>>> broken in several patches.  This is set 1 of 4.
> >>>>>>>>>
> >>>>>>>>> HP BIOS Configuration driver purpose is to provide a driver supporting
> >>>>>>>>> the latest sysfs class firmware attributes framework allowing the user
> >>>>>>>>> to change BIOS settings and security solutions on HP Inc.’s commercial
> >>>>>>>>> notebooks.
> >>>>>>>>>
> >>>>>>>>> Many features of HP Commercial PC’s can be managed using Windows
> >>>>>>>>> Management Instrumentation (WMI). WMI is an implementation of Web-Based
> >>>>>>>>> Enterprise Management (WBEM) that provides a standards-based interface
> >>>>>>>>> for changing and monitoring system settings.  HP BISOCFG driver provides
> >>>>>>>>> a native Linux solution and the exposed features facilitates the
> >>>>>>>>> migration to Linux environments.
> >>>>>>>>>
> >>>>>>>>> The Linux security features to be provided in hp-bioscfg driver enables
> >>>>>>>>> managing the BIOS settings and security solutions via sysfs, a virtual
> >>>>>>>>> filesystem that can be used by user-mode applications.   The new
> >>>>>>>>> documentation cover features such Secure Platform Management, Sure
> >>>>>>>>> Admin, and Sure Start.  Each section provides security feature
> >>>>>>>>> description and identifies sysfs directories and files exposed by
> >>>>>>>>> the driver.
> >>>>>>>>>
> >>>>>>>>> Many HP Commercial PC’s include a feature called Secure Platform
> >>>>>>>>> Management (SPM), which replaces older password-based BIOS settings
> >>>>>>>>> management with public key cryptography. PC secure product management
> >>>>>>>>> begins when a target system is provisioned with cryptographic keys
> >>>>>>>>> that are used to ensure the integrity of communications between system
> >>>>>>>>> management utilities and the BIOS.
> >>>>>>>>>
> >>>>>>>>> HP Commercial PC’s have several BIOS settings that control its behaviour
> >>>>>>>>> and capabilities, many of which are related to security. To prevent
> >>>>>>>>> unauthorized changes to these settings, the system can be configured
> >>>>>>>>> to use a Sure Admin cryptographic signature-based authorization string
> >>>>>>>>> that the BIOS will use to verify authorization to modify the setting.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Jorge Lopez <[e-mail]>
> >>>>>>>>>
> >>>>>>>>> ---
> >>>>>>>>> Based on the latest platform-drivers-x86.git/for-next
> >>>>>>>>> ---
> >>>>>>>>>  .../x86/hp/hp-bioscfg/biosattr-interface.c    | 285 ++++++++
> >>>>>>>>>  drivers/platform/x86/hp/hp-bioscfg/bioscfg.h  | 671 ++++++++++++++++++
> >>>>>>>>>  .../x86/hp/hp-bioscfg/enum-attributes.c       | 521 ++++++++++++++
> >>>>>>>>>  3 files changed, 1477 insertions(+)
> >>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
> >>>>>>>>>  create mode 100644 drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
> >>>>>>>>>
> >>>>>>>>> diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>> new file mode 100644
> >>>>>>>>> index 000000000000..f0c919bf3ab0
> >>>>>>>>> --- /dev/null
> >>>>>>>>> +++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
> >>>>>>>>> @@ -0,0 +1,285 @@
> >>>>>>>>> +// SPDX-License-Identifier: GPL-2.0
> >>>>>>>>> +/*
> >>>>>>>>> + * Functions corresponding to methods under BIOS interface GUID
> >>>>>>>>> + * for use with hp-bioscfg driver.
> >>>>>>>>> + *
> >>>>>>>>> + *  Copyright (c) 2022 Hewlett-Packard Inc.
> >>>>>>>>> + */
> >>>>>>>>> +
> >>>>>>>>> +#include <linux/wmi.h>
> >>>>>>>>> +#include "bioscfg.h"
> >>>>>>>>> +
> >>>>>>>>> +#define SET_DEFAULT_VALUES_METHOD_ID 0x02
> >>>>>>>>> +#define SET_BIOS_DEFAULTS_METHOD_ID  0x03
> >>>>>>>>> +#define SET_ATTRIBUTE_METHOD_ID              0x04
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * set_attribute() - Update an attribute value
> >>>>>>>>> + * @a_name: The attribute name
> >>>>>>>>> + * @a_value: The attribute value
> >>>>>>>>> + *
> >>>>>>>>> + * Sets an attribute to new value
> >>>>>>>>> + */
> >>>>>>>>> +int hp_set_attribute(const char *a_name, const char *a_value)
> >>>>>>>>> +{
> >>>>>>>>> +     size_t security_area_size;
> >>>>>>>>> +     size_t a_name_size, a_value_size;
> >>>>>>>>> +     u16 *buffer = NULL;
> >>>>>>>>> +     u16 *start = NULL;
> >>>>>>>>> +     int  buffer_size;
> >>>>>>>>
> >>>>>>>> You have 2 spaces between int and buffer_size here, please drop
> >>>>>>>> one.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>> +     int ret;
> >>>>>>>>> +     int instance;
> >>>>>>>>> +     char *auth_empty_value = " ";
> >>>>>>>>> +
> >>>>>>>>> +     mutex_lock(&bioscfg_drv.mutex);
> >>>>>>>>> +     if (!bioscfg_drv.bios_attr_wdev) {
> >>>>>>>>> +             ret = -ENODEV;
> >>>>>>>>> +             goto out_set_attribute;
> >>>>>>>>> +     }
> >>>>>>>>> +
> >>>>>>>>> +     instance = get_password_instance_for_type(SETUP_PASSWD);
> >>>>>>>>> +     if (instance < 0)
> >>>>>>>>> +             goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> +     if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
> >>>>>>>>> +             strncpy(bioscfg_drv.password_data[instance].current_password,
> >>>>>>>>> +                     auth_empty_value,
> >>>>>>>>> +                     sizeof(bioscfg_drv.password_data[instance].current_password));
> >>>>>>>>
> >>>>>>>> strncpy does not guarantee 0 termination of the destination buffer,
> >>>>>>>> please use strscpy.
> >>>>>>>>
> >>>>>>>>> +
> >>>>>>>>> +     a_name_size = calculate_string_buffer(a_name);
> >>>>>>>>> +     a_value_size = calculate_string_buffer(a_value);
> >>>>>>>>> +     security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
> >>>>>>>>> +     buffer_size = a_name_size + a_value_size + security_area_size;
> >>>>>>>>> +
> >>>>>>>>> +     buffer = kzalloc(buffer_size, GFP_KERNEL);
> >>>>>>>>> +     if (!buffer) {
> >>>>>>>>> +             ret = -ENOMEM;
> >>>>>>>>> +             goto out_set_attribute;
> >>>>>>>>> +     }
> >>>>>>>>> +
> >>>>>>>>> +     /* build variables to set */
> >>>>>>>>> +     start = buffer;
> >>>>>>>>> +     start = ascii_to_utf16_unicode(start, a_name);
> >>>>>>>>> +     if (!start)
> >>>>>>>>> +             goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> +     start = ascii_to_utf16_unicode(start, a_value);
> >>>>>>>>> +     if (!start)
> >>>>>>>>> +             goto out_set_attribute;
> >>>>>>>>> +
> >>>>>>>>> +     populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
> >>>>>>>>> +     ret = hp_wmi_set_bios_setting(buffer, buffer_size);
> >>>>>>>>> +
> >>>>>>>>> +
> >>>>>>>>> +out_set_attribute:
> >>>>>>>>> +     kfree(buffer);
> >>>>>>>>> +     mutex_unlock(&bioscfg_drv.mutex);
> >>>>>>>>> +     return ret;
> >>>>>>>>> +}
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * hp_wmi_perform_query
> >>>>>>>>> + *
> >>>>>>>>> + * query:    The commandtype (enum hp_wmi_commandtype)
> >>>>>>>>> + * write:    The command (enum hp_wmi_command)
> >>>>>>>>> + * buffer:   Buffer used as input and/or output
> >>>>>>>>> + * insize:   Size of input buffer
> >>>>>>>>> + * outsize:  Size of output buffer
> >>>>>>>>> + *
> >>>>>>>>> + * returns zero on success
> >>>>>>>>> + *         an HP WMI query specific error code (which is positive)
> >>>>>>>>> + *         -EINVAL if the query was not successful at all
> >>>>>>>>> + *         -EINVAL if the output buffer size exceeds buffersize
> >>>>>>>>> + *
> >>>>>>>>> + * Note: The buffersize must at least be the maximum of the input and output
> >>>>>>>>> + *       size. E.g. Battery info query is defined to have 1 byte input
> >>>>>>>>> + *       and 128 byte output. The caller would do:
> >>>>>>>>> + *       buffer = kzalloc(128, GFP_KERNEL);
> >>>>>>>>> + *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
> >>>>>>>>> + */
> >>>>>>>>> +int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
> >>>>>>>>> +{
> >>>>>>>>> +     struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
> >>>>>>>>> +     struct bios_return *bios_return;
> >>>>>>>>> +     union acpi_object *obj = NULL;
> >>>>>>>>> +     struct bios_args *args = NULL;
> >>>>>>>>> +     int mid, actual_insize, actual_outsize;
> >>>>>>>>> +     size_t bios_args_size;
> >>>>>>>>> +     int ret;
> >>>>>>>>> +
> >>>>>>>>> +     mid = encode_outsize_for_pvsz(outsize);
> >>>>>>>>> +     if (WARN_ON(mid < 0))
> >>>>>>>>> +             return mid;
> >>>>>>>>> +
> >>>>>>>>> +     actual_insize = insize;
> >>>>>>>>> +     bios_args_size = struct_size(args, data, insize);
> >>>>>>>>> +     args = kmalloc(bios_args_size, GFP_KERNEL);
> >>>>>>>>> +     if (!args)
> >>>>>>>>> +             return -ENOMEM;
> >>>>>>>>> +
> >>>>>>>>> +     input.length = bios_args_size;
> >>>>>>>>> +     input.pointer = args;
> >>>>>>>>> +
> >>>>>>>>> +     args->signature = 0x55434553;
> >>>>>>>>> +     args->command = command;
> >>>>>>>>> +     args->commandtype = query;
> >>>>>>>>> +     args->datasize = insize;
> >>>>>>>>> +     memcpy(args->data, buffer, flex_array_size(args, data, insize));
> >>>>>>>>> +
> >>>>>>>>> +     ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
> >>>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>>>>>> +     if (ret)
> >>>>>>>>> +             goto out_free;
> >>>>>>>>> +
> >>>>>>>>> +     obj = output.pointer;
> >>>>>>>>> +     if (!obj) {
> >>>>>>>>> +             ret = -EINVAL;
> >>>>>>>>> +             goto out_free;
> >>>>>>>>> +     }
> >>>>>>>>> +
> >>>>>>>>
> >>>>>>>> You need to check the type of obj here before dereferencing
> >>>>>>>> obj as if it is a buffer.
> >>>>>>>>
> >>>>>>>>> +     bios_return = (struct bios_return *)obj->buffer.pointer;
> >>>>>>>>> +     ret = bios_return->return_code;
> >>>>>>>>> +     bioscfg_drv.last_wmi_status = ret;
> >>>>>>>>> +     if (ret) {
> >>>>>>>>> +             if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
> >>>>>>>>> +                 ret != HPWMI_RET_UNKNOWN_CMDTYPE)
> >>>>>>>>> +                     pr_warn("query 0x%x returned error 0x%x\n", query, ret);
> >>>>>>>>> +             goto out_free;
> >>>>>>>>> +     }
> >>>>>>>>> +
> >>>>>>>>> +     /* Ignore output data of zero size */
> >>>>>>>>> +     if (!outsize)
> >>>>>>>>> +             goto out_free;
> >>>>>>>>> +
> >>>>>>>>> +     actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
> >>>>>>>>> +     memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
> >>>>>>>>> +     memset(buffer + actual_outsize, 0, outsize - actual_outsize);
> >>>>>>>>> +
> >>>>>>>>> +out_free:
> >>>>>>>>> +     kfree(obj);
> >>>>>>>>> +     kfree(args);
> >>>>>>>>> +     return ret;
> >>>>>>>>> +}
> >>>>>>>>> +
> >>>>>>>>> +/*
> >>>>>>>>> + * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
> >>>>>>>>> + *
> >>>>>>>>> + * @p:   Unicode buffer address
> >>>>>>>>> + * @str: string to convert to unicode
> >>>>>>>>> + *
> >>>>>>>>> + * Returns a void pointer to the buffer containing unicode string
> >>>>>>>>> + */
> >>>>>>>>> +void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
> >>>>>>>>> +{
> >>>>>>>>> +     int len = strlen(str);
> >>>>>>>>> +     int ret;
> >>>>>>>>> +
> >>>>>>>>> +     /*
> >>>>>>>>> +      * Add null character when reading an empty string
> >>>>>>>>> +      */
> >>>>>>>>> +     if (len == 0) {
> >>>>>>>>> +             *p++ = 2;
> >>>>>>>>> +             *p++ = (u8)0x00;
> >>>>>>>>> +             return p;
> >>>>>>>>
> >>>>>>>> This does not match with calculate_string_buffer() which will
> >>>>>>>> return 2 for a 0 length string while you are using 4 bytes here.
> >>>>>>>>
> >>>>>>>> I guess this may also be why you need to use " " for
> >>>>>>>> auth_empty_value above, so as to avoid this bug.
> >>>>>>>>
> >>>>>>> HP BIOS expects 2 characters when an empty string is being converted
> >>>>>>> to u16 hence the reason for returning 2 instead of zero.  This is an
> >>>>>>> intended behavior and needed when  allocating a buffer and writing to
> >>>>>>> BIOS.
> >>>>>>
> >>>>>> Right I understand that, it wants 2 characters for the 16 bit length
> >>>>>> word, but why not write 0 to that 16 bit length word. Why actually
> >>>>>> say the string-buffer length is 2 bytes long / and then write
> >>>>>> a 16-bit word with value 0?
> >>>>>>
> >>>>>> What you are doing now creates a 4 byte buffer like this:
> >>>>>>
> >>>>>> u8 buf[4] = { 0x02, 0x00, 0x00, 0x00 }
> >>>>>>
> >>>>>> Why not just create a 2 byte buffer like this:
> >>>>>>
> >>>>>> u8 buf[2] = { 0x00, 0x00 }
> >>>>>>
> >>>>>> ?
> >>>>>>
> >>>>>>
> >>>>>> Also I'm wondering why the empty auth string is " " and
> >>>>>> not "" ?
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> The string returned for an empty string is 4 bytes.  The returned
> >>>>> string includes two bytes for the string size in bytes and the
> >>>>> remaining bytes are the string.
> >>>>> Size =  0x02, 0x00
> >>>>> String = 0x00, 0x00
> >>>>>
> >>>>> All strings return include the string size in bytes followed by the u16 string
> >>>>
> >>>> Right I understand that, but why is the "String = 0x00, 0x00"
> >>>> there ? All the non-0-length strings are not 0 terminated,
> >>>> why does the zero length string needs to be specified as length 2
> >>>> (1 u16) and then have that u16 be a 0 terminator ?
> >>>>
> >>> It is a specific format required by BIOS for any zero-length strings.
> >>> I don't know the reason why BIOS wants that format.
> >>>
> >>>
> >>>> Have you tried just using Size[2] =  0x00, 0x00 and String[0] for
> >>>> an empty string?
> >>>>
> >>>
> >>> I tried during the development process and each time the data is
> >>> rejected by BIOS.
> >>
> >> Ok, well in that case you are going to need your own
> >> ascii_to_utf16_unicode() to handle the weird case for the
> >> 0 sized string, so no need to move the dell-wmi-sysman versions
> >> to the shared wmi code.
> >>
> >> But please do start with a copy of the Dell function and then
> >> add the special case for the 0 len string, since the original
> >> version above does not properly handle errors.
> >>
> >> Also this means you need to update the hp calculate_string_buffer()
> >> copy to properly return 4 rather then 2 for the bufsize for
> >> a 0 length string.
> >>
> >
> > I will do so. Thanks.
> > BTW, changes requested for sysman.c will require changes to two other
> > DELL source files;
> > biosattr-interface.c and passwordattr-interface.c.
> > All I can do is to verify it compiles ok.
>
> Note that since you now need a special version to deal
> with the 0 length string weirdness, you can just make
> a private copy of the dell functions into the hp code
> and then modify that to add the special case for the
> 0 length strings.
>
> So there is no longer a need to move the dell versions
> out into wmi.c since the hp code will need a modified
> version anyways (so the code cannot be shared).
>

Understood.  I just wanted to make sure.
Thanks

> Regards,
>
> Hans
>

Jorge Lopez Nov. 11, 2022, 11 p.m. UTC | #11

Hi Hans,

A quick note to check the next step.   The changes requested for
enum-attributes,c and several supporting functions will impact other
source files.  To save reviewing time,  I am planning to introduce the
same changes across all source files and then proceed to submit the
review.   Is this option acceptable?.

Regards,

Hans de Goede Nov. 12, 2022, 8:30 a.m. UTC | #12

Hi,

On 11/12/22 00:00, Jorge Lopez wrote:
> Hi Hans,
> 
> A quick note to check the next step.   The changes requested for
> enum-attributes,c and several supporting functions will impact other
> source files.  To save reviewing time,  I am planning to introduce the
> same changes across all source files and then proceed to submit the
> review.   Is this option acceptable?.

Yes applying the same changes to all the source files is
the *intention*. This is why I stopped reviewing after
reviewing the first set of files.

Regards,

Hans

Jorge Lopez Nov. 14, 2022, 2:13 p.m. UTC | #13

On Sat, Nov 12, 2022 at 2:30 AM Hans de Goede <[e-mail]> wrote:
>
> Hi,
>
> On 11/12/22 00:00, Jorge Lopez wrote:
> > Hi Hans,
> >
> > A quick note to check the next step.   The changes requested for
> > enum-attributes,c and several supporting functions will impact other
> > source files.  To save reviewing time,  I am planning to introduce the
> > same changes across all source files and then proceed to submit the
> > review.   Is this option acceptable?.
>
> Yes applying the same changes to all the source files is
> the *intention*. This is why I stopped reviewing after
> reviewing the first set of files.
>

That was understanding but I wanted to make sure.
Thanks for the confirmation.

> Regards,
>
> Hans
>
>

Patch

diff --git a/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
new file mode 100644
index 000000000000..f0c919bf3ab0
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/biosattr-interface.c
@@ -0,0 +1,285 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to methods under BIOS interface GUID
+ * for use with hp-bioscfg driver.
+ *
+ *  Copyright (c) 2022 Hewlett-Packard Inc.
+ */
+
+#include <linux/wmi.h>
+#include "bioscfg.h"
+
+#define SET_DEFAULT_VALUES_METHOD_ID	0x02
+#define SET_BIOS_DEFAULTS_METHOD_ID	0x03
+#define SET_ATTRIBUTE_METHOD_ID		0x04
+
+/*
+ * set_attribute() - Update an attribute value
+ * @a_name: The attribute name
+ * @a_value: The attribute value
+ *
+ * Sets an attribute to new value
+ */
+int hp_set_attribute(const char *a_name, const char *a_value)
+{
+	size_t security_area_size;
+	size_t a_name_size, a_value_size;
+	u16 *buffer = NULL;
+	u16 *start = NULL;
+	int  buffer_size;
+	int ret;
+	int instance;
+	char *auth_empty_value = " ";
+
+	mutex_lock(&bioscfg_drv.mutex);
+	if (!bioscfg_drv.bios_attr_wdev) {
+		ret = -ENODEV;
+		goto out_set_attribute;
+	}
+
+	instance = get_password_instance_for_type(SETUP_PASSWD);
+	if (instance < 0)
+		goto out_set_attribute;
+
+	if (strlen(bioscfg_drv.password_data[instance].current_password) == 0)
+		strncpy(bioscfg_drv.password_data[instance].current_password,
+			auth_empty_value,
+			sizeof(bioscfg_drv.password_data[instance].current_password));
+
+	a_name_size = calculate_string_buffer(a_name);
+	a_value_size = calculate_string_buffer(a_value);
+	security_area_size = calculate_security_buffer(bioscfg_drv.password_data[instance].current_password);
+	buffer_size = a_name_size + a_value_size + security_area_size;
+
+	buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto out_set_attribute;
+	}
+
+	/* build variables to set */
+	start = buffer;
+	start = ascii_to_utf16_unicode(start, a_name);
+	if (!start)
+		goto out_set_attribute;
+
+	start = ascii_to_utf16_unicode(start, a_value);
+	if (!start)
+		goto out_set_attribute;
+
+	populate_security_buffer(start, bioscfg_drv.password_data[instance].current_password);
+	ret = hp_wmi_set_bios_setting(buffer, buffer_size);
+
+
+out_set_attribute:
+	kfree(buffer);
+	mutex_unlock(&bioscfg_drv.mutex);
+	return ret;
+}
+
+/*
+ * hp_wmi_perform_query
+ *
+ * query:	The commandtype (enum hp_wmi_commandtype)
+ * write:	The command (enum hp_wmi_command)
+ * buffer:	Buffer used as input and/or output
+ * insize:	Size of input buffer
+ * outsize:	Size of output buffer
+ *
+ * returns zero on success
+ *         an HP WMI query specific error code (which is positive)
+ *         -EINVAL if the query was not successful at all
+ *         -EINVAL if the output buffer size exceeds buffersize
+ *
+ * Note: The buffersize must at least be the maximum of the input and output
+ *       size. E.g. Battery info query is defined to have 1 byte input
+ *       and 128 byte output. The caller would do:
+ *       buffer = kzalloc(128, GFP_KERNEL);
+ *       ret = hp_wmi_perform_query(HPWMI_BATTERY_QUERY, HPWMI_READ, buffer, 1, 128)
+ */
+int hp_wmi_perform_query(int query, enum hp_wmi_command command, void *buffer, int insize, int outsize)
+{
+	struct acpi_buffer input, output = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct bios_return *bios_return;
+	union acpi_object *obj = NULL;
+	struct bios_args *args = NULL;
+	int mid, actual_insize, actual_outsize;
+	size_t bios_args_size;
+	int ret;
+
+	mid = encode_outsize_for_pvsz(outsize);
+	if (WARN_ON(mid < 0))
+		return mid;
+
+	actual_insize = insize;
+	bios_args_size = struct_size(args, data, insize);
+	args = kmalloc(bios_args_size, GFP_KERNEL);
+	if (!args)
+		return -ENOMEM;
+
+	input.length = bios_args_size;
+	input.pointer = args;
+
+	args->signature = 0x55434553;
+	args->command = command;
+	args->commandtype = query;
+	args->datasize = insize;
+	memcpy(args->data, buffer, flex_array_size(args, data, insize));
+
+	ret = wmi_evaluate_method(HP_WMI_BIOS_GUID, 0, mid, &input, &output);
+	bioscfg_drv.last_wmi_status = ret;
+	if (ret)
+		goto out_free;
+
+	obj = output.pointer;
+	if (!obj) {
+		ret = -EINVAL;
+		goto out_free;
+	}
+
+	bios_return = (struct bios_return *)obj->buffer.pointer;
+	ret = bios_return->return_code;
+	bioscfg_drv.last_wmi_status = ret;
+	if (ret) {
+		if (ret != HPWMI_RET_UNKNOWN_COMMAND &&
+		    ret != HPWMI_RET_UNKNOWN_CMDTYPE)
+			pr_warn("query 0x%x returned error 0x%x\n", query, ret);
+		goto out_free;
+	}
+
+	/* Ignore output data of zero size */
+	if (!outsize)
+		goto out_free;
+
+	actual_outsize = min(outsize, (int)(obj->buffer.length - sizeof(*bios_return)));
+	memcpy(buffer, obj->buffer.pointer + sizeof(*bios_return), actual_outsize);
+	memset(buffer + actual_outsize, 0, outsize - actual_outsize);
+
+out_free:
+	kfree(obj);
+	kfree(args);
+	return ret;
+}
+
+/*
+ * ascii_to_utf16_unicode -  Convert ascii string to UTF-16 unicode
+ *
+ * @p:   Unicode buffer address
+ * @str: string to convert to unicode
+ *
+ * Returns a void pointer to the buffer containing unicode string
+ */
+void *ascii_to_utf16_unicode(u16 *p, const u8 *str)
+{
+	int len = strlen(str);
+	int ret;
+
+	/*
+	 * Add null character when reading an empty string
+	 */
+	if (len == 0) {
+		*p++ = 2;
+		*p++ = (u8)0x00;
+		return p;
+	}
+	*p++ = len * 2;
+	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, p, len);
+
+	if (ret < 0) {
+		dev_err(bioscfg_drv.class_dev, "UTF16 conversion failed\n");
+		goto ascii_to_utf16_unicode_out;
+	}
+
+	if ((ret * sizeof(u16)) > U16_MAX) {
+		dev_err(bioscfg_drv.class_dev, "Error string too long\n");
+		goto ascii_to_utf16_unicode_out;
+	}
+
+ascii_to_utf16_unicode_out:
+	p += len;
+	return p;
+}
+
+/*
+ * hp_wmi_set_bios_setting - Set setting's value in BIOS
+ *
+ * @input_buffer: Input buffer address
+ * @input_size:   Input buffer size
+ *
+ * Returns: Count of unicode characters written to BIOS if successful, otherwise
+ *		-ENOMEM unable to allocate memory
+ *		-EINVAL buffer not allocated or too small
+ */
+int hp_wmi_set_bios_setting(void *input_buffer, int input_size)
+{
+	union acpi_object *obj;
+	struct acpi_buffer input = {input_size, input_buffer};
+	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+	int ret = 0;
+
+	ret = wmi_evaluate_method(HP_WMI_SET_BIOS_SETTING_GUID, 0, 1, &input, &output);
+
+	obj = output.pointer;
+	if (!obj)
+		return -EINVAL;
+
+	if (obj->type != ACPI_TYPE_INTEGER)
+		ret = -EINVAL;
+
+	ret = obj->integer.value;
+
+	kfree(obj);
+	return ret;
+}
+
+/*
+ * set_bios_defaults() - Resets BIOS defaults
+ *
+ * @deftype: the type of BIOS value reset to issue.
+ *
+ * Resets BIOS defaults
+ */
+int set_bios_defaults(u8 deftype)
+{
+	return -EOPNOTSUPP;
+}
+
+static int bios_attr_set_interface_probe(struct wmi_device *wdev, const void *context)
+{
+	mutex_lock(&bioscfg_drv.mutex);
+	bioscfg_drv.bios_attr_wdev = wdev;
+	mutex_unlock(&bioscfg_drv.mutex);
+	return 0;
+}
+
+static void bios_attr_set_interface_remove(struct wmi_device *wdev)
+{
+	mutex_lock(&bioscfg_drv.mutex);
+	bioscfg_drv.bios_attr_wdev = NULL;
+	mutex_unlock(&bioscfg_drv.mutex);
+}
+
+static const struct wmi_device_id bios_attr_set_interface_id_table[] = {
+	{ .guid_string = HP_WMI_BIOS_GUID},
+	{ },
+};
+static struct wmi_driver bios_attr_set_interface_driver = {
+	.driver = {
+		.name = DRIVER_NAME
+	},
+	.probe = bios_attr_set_interface_probe,
+	.remove = bios_attr_set_interface_remove,
+	.id_table = bios_attr_set_interface_id_table,
+};
+
+int init_bios_attr_set_interface(void)
+{
+	return wmi_driver_register(&bios_attr_set_interface_driver);
+}
+
+void exit_bios_attr_set_interface(void)
+{
+	wmi_driver_unregister(&bios_attr_set_interface_driver);
+}
+
+MODULE_DEVICE_TABLE(wmi, bios_attr_set_interface_id_table);
diff --git a/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
new file mode 100644
index 000000000000..4409481f84f2
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/bioscfg.h
@@ -0,0 +1,671 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Definitions for kernel modules using hp_bioscfg driver
+ *
+ *  Copyright (c) 2022 HP Development Company, L.P.
+ */
+
+#ifndef _HP_BIOSCFG_H_
+#define _HP_BIOSCFG_H_
+
+#include <linux/wmi.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/capability.h>
+#include <linux/nls.h>
+
+
+#define DRIVER_NAME	"hp-bioscfg"
+
+#define MAX_BUFF		512
+#define MAX_KEY_MOD		256
+#define MAX_PASSWD_SIZE		64
+#define MAX_MESSAGE_SIZE        256
+
+#define SPM_STR_DESC	"Secure Platform Management"
+#define SPM_STR		"SPM"
+#define SURE_START_DESC "Sure Start"
+#define SURE_START_STR  "Sure_Start"
+#define SURE_ADMIN_DESC "Sure Admin"
+#define SURE_ADMIN_STR  "Sure_Admin"
+#define SETUP_PASSWD	"Setup Password"
+#define POWER_ON_PASSWD	"Power-On Password"
+
+#define LANG_CODE_STR		"en_US.UTF-8"
+#define SCHEDULE_POWER_ON	"Scheduled Power-On"
+
+/* Sure Admin Functions */
+
+#define UTF_PREFIX	((unsigned char *)"<utf-16/>")
+#define BEAM_PREFIX	((unsigned char *)"<BEAM/>")
+
+/* mechanism - Authentication attribute */
+
+#define MAX_MECHANISM_TYPES 3
+
+enum mechanism_values {
+	PASSWORD	= 0x00,
+	NOT_PROVISION   = 0x00,
+	SIGNING_KEY	= 0x01,
+	ENDORSEMENT_KEY = 0x02
+};
+
+static const char * const spm_mechanism_types[] = {
+	"not provision",
+	"signing-key",
+	"endorsement-key"
+};
+
+static const char * const passwd_mechanism_types[] = {
+	"password",
+};
+
+/* roles - Authentication attribute */
+enum role_values {
+	BIOS_ADMIN	= 0x00,
+	POWER_ON	= 0x01,
+	BIOS_SPM	= 0x02
+};
+
+static const char * const role_type[] = {
+	"bios-admin",
+	"power-on",
+	"enhanced-bios-auth"
+};
+
+
+#define HP_WMI_BIOS_GUID		"5FB7F034-2C63-45e9-BE91-3D44E2C707E4"
+
+#define HP_WMI_BIOS_STRING_GUID		"988D08E3-68F4-4c35-AF3E-6A1B8106F83C"
+#define HP_WMI_BIOS_INTEGER_GUID	"8232DE3D-663D-4327-A8F4-E293ADB9BF05"
+#define HP_WMI_BIOS_ENUMERATION_GUID	"2D114B49-2DFB-4130-B8FE-4A3C09E75133"
+#define HP_WMI_BIOS_ORDERED_LIST_GUID	"14EA9746-CE1F-4098-A0E0-7045CB4DA745"
+#define HP_WMI_BIOS_PASSWORD_GUID	"322F2028-0F84-4901-988E-015176049E2D"
+#define HP_WMI_SET_BIOS_SETTING_GUID	"1F4C91EB-DC5C-460b-951D-C7CB9B4B8D5E"
+
+enum hp_wmi_spm_commandtype {
+	HPWMI_SECUREPLATFORM_GET_STATE  = 0x10,
+	HPWMI_SECUREPLATFORM_SET_KEK	= 0x11,
+	HPWMI_SECUREPLATFORM_SET_SK	= 0x12,
+};
+
+enum hp_wmi_surestart_commandtype {
+	HPWMI_SURESTART_GET_LOG_COUNT	= 0x01,
+	HPWMI_SURESTART_GET_LOG		= 0x02,
+};
+
+enum hp_wmi_command {
+	HPWMI_READ		= 0x01,
+	HPWMI_WRITE		= 0x02,
+	HPWMI_ODM		= 0x03,
+	HPWMI_SURESTART		= 0x20006,
+	HPWMI_GM		= 0x20008,
+	HPWMI_SECUREPLATFORM	= 0x20010,
+};
+
+struct bios_return {
+	u32 sigpass;
+	u32 return_code;
+};
+
+enum hp_return_value {
+	HPWMI_RET_WRONG_SIGNATURE	= 0x02,
+	HPWMI_RET_UNKNOWN_COMMAND	= 0x03,
+	HPWMI_RET_UNKNOWN_CMDTYPE	= 0x04,
+	HPWMI_RET_INVALID_PARAMETERS	= 0x05,
+};
+
+enum wmi_error_values {
+	SUCCESS			= 0x00,
+	CMD_FAILED			= 0x01,
+	INVALID_SIGN			= 0x02,
+	INVALID_CMD_VALUE		= 0x03,
+	INVALID_CMD_TYPE		= 0x04,
+	INVALID_DATA_SIZE		= 0x05,
+	INVALID_CMD_PARAM		= 0x06,
+	ENCRYP_CMD_REQUIRED		= 0x07,
+	NO_SECURE_SESSION		= 0x08,
+	SECURE_SESSION_FOUND		= 0x09,
+	SECURE_SESSION_FAILED		= 0x0A,
+	AUTH_FAILED			= 0x0B,
+	INVALID_BIOS_AUTH		= 0x0E,
+	NONCE_DID_NOT_MATCH		= 0x18,
+	GENERIC_ERROR			= 0x1C,
+	BIOS_ADMIN_POLICY_NOT_MET	= 0x28,
+	BIOS_ADMIN_NOT_SET		= 0x38,
+	P21_NO_PROVISIONED		= 0x1000,
+	P21_PROVISION_IN_PROGRESS	= 0x1001,
+	P21_IN_USE			= 0x1002,
+	HEP_NOT_ACTIVE			= 0x1004,
+	HEP_ALREADY_SET		= 0x1006,
+	HEP_CHECK_STATE		= 0x1007
+};
+
+enum spm_features {
+	HEP_ENABLED		= 0x01,
+	PLATFORM_RECOVERY	= 0x02,
+	ENHANCED_BIOS_AUTH_MODE	= 0x04
+};
+
+
+/*
+ * struct bios_args buffer is dynamically allocated.  New WMI command types
+ * were introduced that exceeds 128-byte data size.  Changes to handle
+ * the data size allocation scheme were kept in hp_wmi_perform_qurey function.
+ */
+struct bios_args {
+	u32 signature;
+	u32 command;
+	u32 commandtype;
+	u32 datasize;
+	u8 data[];
+};
+
+
+#pragma pack(1)
+struct secureplatform_provisioning_data {
+	u8 state;
+	u8 version[2];
+	u8 reserved1;
+	u32 features;
+	u32 nonce;
+	u8 reserved2[28];
+	u8 sk_mod[MAX_KEY_MOD];
+	u8 kek_mod[MAX_KEY_MOD];
+};
+
+#pragma pack()
+
+
+struct string_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+	u8 current_value[MAX_BUFF];
+	u8 new_value[MAX_BUFF];
+	u8 path[MAX_BUFF];
+	u32 is_readonly;
+	u32 display_in_ui;
+	u32 requires_physical_presence;
+	u32 sequence;
+	u32 prerequisitesize;
+	u8 prerequisites[MAX_BUFF];
+	u32 security_level;
+	u32 min_length;
+	u32 max_length;
+	u8 display_name_language_code[MAX_BUFF];
+	u32 type;
+};
+
+struct integer_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+	u32 current_value;
+	u32 new_value;
+	u8 path[MAX_BUFF];
+	u32 is_readonly;
+	u32 display_in_ui;
+	u32 requires_physical_presence;
+	u32 sequence;
+	u32 prerequisitesize;
+	u8 prerequisites[MAX_BUFF];
+	u32 security_level;
+	u32 lower_bound;
+	u32 upper_bound;
+	u32 scalar_increment;
+	u8 display_name_language_code[MAX_BUFF];
+	u32 type;
+};
+
+struct enumeration_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+	u8 path[MAX_BUFF];
+	u32 is_readonly;
+	u32 display_in_ui;
+	u32 requires_physical_presence;
+	u32 sequence;
+	u32 prerequisitesize;
+	u8 prerequisites[MAX_BUFF];
+	u32 security_level;
+	u8 current_value[MAX_BUFF];
+	u8 new_value[MAX_BUFF];
+	u32 size;
+	u8 possible_values[MAX_BUFF];
+	u8 display_name_language_code[MAX_BUFF];
+	u32 type;
+};
+
+struct ordered_list_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+	u8 current_value[MAX_BUFF];
+	u8 new_value[MAX_BUFF];
+	u8 path[MAX_BUFF];
+	u32 is_readonly;
+	u32 display_in_ui;
+	u32 requires_physical_presence;
+	u32 sequence;
+	u32 prerequisitesize;
+	u8 prerequisites[MAX_BUFF];
+	u32 security_level;
+	u32 size;
+	u8 elements[MAX_BUFF];
+	u8 display_name_language_code[MAX_BUFF];
+	u32 type;
+};
+
+struct password_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+	u8 current_password[MAX_PASSWD_SIZE];
+	u8 new_password[MAX_PASSWD_SIZE];
+	u8 path[MAX_BUFF];
+	u32 is_readonly;
+	u32 display_in_ui;
+	u32 requires_physical_presence;
+	u32 sequence;
+	u32 prerequisitesize;
+	u8 prerequisites[MAX_BUFF];
+	u32 security_level;
+	u32 min_password_length;
+	u32 max_password_length;
+	u32 encoding_size;
+	u8 supported_encoding[MAX_BUFF];
+	u8 display_name_language_code[MAX_BUFF];
+	u32 is_enabled;
+
+	// 'bios-admin' 'power-on'
+	u32 role;
+
+	//'password'
+	u32 mechanism;
+	u32 type;
+};
+
+struct secure_platform_data {
+	struct kobject *attr_name_kobj;
+	u8 attribute_name[MAX_BUFF];
+	u8 display_name[MAX_BUFF];
+
+	u8 *endorsement_key;
+	u8 *signing_key;
+
+	u32 is_enabled;
+	u32 mechanism;
+	u32 type;
+};
+
+struct bioscfg_priv {
+	struct wmi_device *password_attr_wdev;
+	struct wmi_device *bios_attr_wdev;
+	struct kset *authentication_dir_kset;
+	struct kset *main_dir_kset;
+	struct device *class_dev;
+	struct string_data *string_data;
+	u32 string_instances_count;
+	struct integer_data *integer_data;
+	u32 integer_instances_count;
+	struct enumeration_data *enumeration_data;
+	u32 enumeration_instances_count;
+	struct ordered_list_data *ordered_list_data;
+	u32 ordered_list_instances_count;
+	struct password_data *password_data;
+	u32 password_instances_count;
+
+	struct kobject *sure_start_attr_kobj;
+	struct kobject *sure_admin_attr_kobj;
+	struct secure_platform_data spm_data;
+
+	int  last_wmi_status;
+	bool pending_reboot;
+	struct mutex mutex;
+};
+
+/* global structure used by multiple WMI interfaces */
+extern struct bioscfg_priv bioscfg_drv;
+
+enum hp_wmi_data_type {
+	HPWMI_STRING_TYPE		= 0x00,
+	HPWMI_INTEGER_TYPE		= 0x01,
+	HPWMI_ENUMERATION_TYPE		= 0x02,
+	HPWMI_ORDERED_LIST_TYPE		= 0x03,
+	HPWMI_PASSWORD_TYPE		= 0x04,
+	HPWMI_SECURE_PLATFORM_TYPE	= 0x05,
+	HPWMI_SURE_START_TYPE		= 0x06,
+	HPWMI_SURE_ADMIN_TYPE           = 0x07,
+};
+
+enum hp_wmi_data_elements {
+
+	/* Common elements */
+	NAME = 0,
+	VALUE = 1,
+	PATH = 2,
+	IS_READONLY = 3,
+	DISPLAY_IN_UI = 4,
+	REQUIRES_PHYSICAL_PRESENCE = 5,
+	SEQUENCE = 6,
+	PREREQUISITE_SIZE = 7,
+	PREREQUISITES = 8,
+	SECURITY_LEVEL = 9,
+
+	/* String elements */
+	STR_MIN_LENGTH = 10,
+	STR_MAX_LENGTH = 11,
+
+	/* Integer elements */
+	INT_LOWER_BOUND = 10,
+	INT_UPPER_BOUND = 11,
+	INT_SCALAR_INCREMENT = 12,
+
+	/* Enumeration elements */
+	ENUM_CURRENT_VALUE = 10,
+	ENUM_SIZE = 11,
+	ENUM_POSSIBLE_VALUES = 12,
+
+	/* Ordered list elements */
+	ORD_LIST_SIZE = 10,
+	ORD_LIST_ELEMENTS = 11,
+
+	/* Password elements */
+	PSWD_MIN_LENGTH = 10,
+	PSWD_MAX_LENGTH = 11,
+	PSWD_SIZE = 12,
+	PSWD_SUPPORTED_ENCODING = 13,
+	PSWD_IS_SET = 14
+};
+
+
+static const int hp_wmi_elements_count[] = {
+	12,   // string
+	13,   // integer
+	13,   // enumeration
+	12,   // ordered list
+	15    // password
+};
+
+#define get_instance_id(type)							\
+static int get_##type##_instance_id(struct kobject *kobj)			\
+{										\
+	int i; \
+								\
+	for (i = 0; i <= bioscfg_drv.type##_instances_count; i++) { \
+		if (!(strcmp(kobj->name, bioscfg_drv.type##_data[i].attribute_name))) \
+			return i;						\
+	}									\
+	return -EIO;								\
+}
+
+#define get_instance_id_for_attribute(type)			\
+static int get_instance_id_for_##type(char *attr_name)	        \
+{										\
+	int i;									\
+										\
+	for (i = 0; i < bioscfg_drv.type##_instances_count; i++) {		\
+		if (strcmp(bioscfg_drv.type##_data[i].attribute_name, attr_name) == 0)						\
+			return i;						\
+	}									\
+	return -EIO;								\
+}
+
+#define attribute_s_property_show(name, type)					\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].name);	\
+	return 0;								\
+}
+/* There is no need to keep track of default and current values
+ * separately
+ */
+#define attribute_s_default_property_show(name, type, new_name)			\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%s\n", bioscfg_drv.type##_data[i].new_name);	\
+	return 0;								\
+}
+
+#define attribute_n_default_property_show(name, type, new_name)			\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].new_name); \
+	return 0;								\
+}
+
+#define attribute_n_property_show(name, type)					\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr,	\
+			   char *buf)						\
+{										\
+	int i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		return sprintf(buf, "%d\n", bioscfg_drv.type##_data[i].name);	\
+	return 0;								\
+}
+
+
+#define attribute_property_store(curr_val, type)				\
+static ssize_t curr_val##_store(struct kobject *kobj,				\
+				struct kobj_attribute *attr,			\
+				const char *buf, size_t count)			\
+{										\
+	char *p = NULL;								\
+	char *attr_value = NULL;						\
+	char *attr_name = NULL;							\
+	int i;									\
+	int ret = -EIO;								\
+										\
+	attr_name = kstrdup(kobj->name, GFP_KERNEL);				\
+	if (!attr_name)								\
+		return -ENOMEM;							\
+										\
+	attr_value = kstrdup(buf, GFP_KERNEL);					\
+	if (!attr_value)							\
+		return -ENOMEM;							\
+										\
+	p = memchr(attr_value, '\n', count);					\
+	if (p != NULL)								\
+		*p = '\0';							\
+										\
+	i = get_##type##_instance_id(kobj);					\
+	if (i >= 0)								\
+		ret = validate_##type##_input(i, attr_value);			\
+	if (!ret)								\
+		ret = hp_set_attribute(attr_name, attr_value);			\
+	if (!ret)								\
+		update_##type##_value(i);					\
+										\
+	clear_all_passwords();							\
+	kfree(attr_name);							\
+	kfree(attr_value);							\
+										\
+	return ret ? ret : count;						\
+}
+
+#define attribute_spm_n_property_show(name, type)				\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
+{									\
+	return sprintf(buf, "%d\n", bioscfg_drv.type##_data.name);\
+}
+
+#define attribute_spm_s_property_show(name, type)				\
+static ssize_t name##_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) \
+{									\
+	return sprintf(buf, "%s\n", bioscfg_drv.type##_data.name);		\
+}
+
+#define check_property_type(attr, prop, valuetype)\
+	(attr##_obj[prop].type != valuetype)
+
+#define HPWMI_BINATTR_RW(_group, _name, _size)	\
+static struct bin_attribute _group##_##_name =	\
+__BIN_ATTR(_name, 0444 | 0200, _group##_##_name##_read, _group##_##_name##_write, _size)
+
+/*
+ * Prototypes
+ */
+union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string);
+int get_instance_count(const char *guid_string);
+void strlcpy_attr(char *dest, char *src);
+void update_attribute_permissions(u32 isReadOnly, struct kobj_attribute *current_val);
+void friendly_user_name_update(char *path, const char *attr_name,
+				char *attr_display, int attr_size);
+
+/* String attributes */
+int populate_string_buffer_data(union acpi_object *str_obj,
+			 int instance_id,
+			 struct kobject *attr_name_kobj);
+int populate_string_elements_from_buffer(union acpi_object *string_obj,
+					 int instance_id,
+					 enum hp_wmi_data_type type);
+int alloc_string_data(void);
+void exit_string_attributes(void);
+int populate_string_package_data(union acpi_object *str_obj,
+				 int instance_id,
+				 struct kobject *attr_name_kobj);
+int populate_string_elements_from_package(union acpi_object *str_obj,
+						  int instance_id,
+						  enum hp_wmi_data_type type);
+
+/* Integer attributes */
+int populate_integer_buffer_data(union acpi_object *integer_obj,
+			  int instance_id,
+			  struct kobject *attr_name_kobj);
+int populate_integer_elements_from_buffer(union acpi_object *integer_obj,
+					  int instance_id,
+					  enum hp_wmi_data_type type);
+int alloc_integer_data(void);
+void exit_integer_attributes(void);
+int populate_integer_package_data(union acpi_object *integer_obj,
+				  int instance_id,
+				  struct kobject *attr_name_kobj);
+int populate_integer_elements_from_package(union acpi_object *integer_obj,
+						  int instance_id,
+						  enum hp_wmi_data_type type);
+
+/* Enumeration attributes */
+int populate_enumeration_buffer_data(union acpi_object *enum_obj,
+			      int instance_id,
+			      struct kobject *attr_name_kobj);
+int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
+					      int instance_id,
+					      enum hp_wmi_data_type type);
+int alloc_enumeration_data(void);
+void exit_enumeration_attributes(void);
+int populate_enumeration_package_data(union acpi_object *enum_obj,
+				      int instance_id,
+				      struct kobject *attr_name_kobj);
+int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
+					       int instance_id,
+					       enum hp_wmi_data_type type);
+
+/* Ordered list */
+int populate_ordered_list_buffer_data(union acpi_object *order_obj, int instance_id,
+				      struct kobject *attr_name_kobj);
+int populate_ordered_list_elements_from_buffer(union acpi_object *order_obj,
+					       int instance_id,
+					       enum hp_wmi_data_type
+					       type);
+int alloc_ordered_list_data(void);
+void exit_ordered_list_attributes(void);
+int populate_ordered_list_package_data(union acpi_object *order_obj,
+				       int instance_id,
+				       struct kobject *attr_name_kobj);
+int populate_ordered_list_elements_from_package(union acpi_object *order_obj,
+						int instance_id,
+						enum hp_wmi_data_type type);
+
+/* Password authentication attributes */
+int populate_password_buffer_data(union acpi_object *password_obj,
+			   int instance_id,
+			   struct kobject *attr_name_kobj);
+int populate_password_elements_from_buffer(union acpi_object *password_obj,
+					   int instance_id,
+					   enum hp_wmi_data_type type);
+int populate_password_package_data(union acpi_object *password_obj, int instance_id,
+				   struct kobject *attr_name_kobj);
+int populate_password_elements_from_package(union acpi_object *password_obj,
+					   int instance_id,
+					    enum hp_wmi_data_type type);
+int alloc_password_data(void);
+int alloc_secure_platform_data(void);
+void exit_password_attributes(void);
+void exit_secure_platform_attributes(void);
+int populate_secure_platform_data(struct kobject *attr_name_kobj);
+int password_is_set(const char *auth);
+int check_spm_is_enabled(void);
+int wmi_error_and_message(int error_code, char *message);
+int hp_wmi_set_bios_setting(void *input_buffer, int input_size);
+int hp_wmi_perform_query(int query, enum hp_wmi_command command,
+				void *buffer, int insize, int outsize);
+
+/* Sure Start attributes */
+void exit_sure_start_attributes(void);
+int populate_sure_start_data(struct kobject *attr_name_kobj);
+
+/* Sure Admin Attributes */
+void exit_sure_admin_attributes(void);
+int populate_sure_admin_data(struct kobject *attr_name_kobj);
+int hp_set_attribute(const char *a_name, const char *a_value);
+int hp_set_attribute_with_payload(const char *a_name,
+				  const char *a_value,
+				  const char *auth_payload);
+int update_attribute_value(char *attr_name, char *attr_value);
+int hp_bios_settings_fill_buffer(void);
+int hp_bios_settings_free_buffer(void);
+int hp_bios_settings_realloc_buffer(char **buf, int *buf_size,
+					   int *alloc_size);
+int append_read_string_attributes(char *buf, int alloc_size,
+					int instance,
+					enum hp_wmi_data_type type);
+int append_read_integer_attributes(char *buf, int alloc_size,
+					 int instance,
+					 enum hp_wmi_data_type type);
+int append_read_enumeration_attributes(char *buf, int alloc_size,
+					     int instance,
+					     enum hp_wmi_data_type type);
+int append_read_ordered_list_attributes(char *buf, int alloc_size,
+					      int instance,
+					      enum hp_wmi_data_type type);
+int append_read_password_attributes(char *buf, int alloc_size,
+					 int instance,
+					 enum hp_wmi_data_type type);
+int append_read_settings(enum hp_wmi_data_type type, char **buf,
+			      int *buf_size, int *alloc_size);
+int append_read_attributes(char **buf, int alloc_size,
+				 int instance, enum hp_wmi_data_type type);
+int set_bios_defaults(u8 defType);
+int get_password_instance_for_type(const char *name);
+int clear_all_passwords(void);
+int clear_passwords(const int instance);
+void exit_bios_attr_set_interface(void);
+int init_bios_attr_set_interface(void);
+size_t calculate_string_buffer(const char *str);
+size_t calculate_security_buffer(const char *authentication);
+void populate_security_buffer(u16 *buffer, const char *authentication);
+ssize_t populate_string_buffer(u16 *buffer, size_t buffer_len, const char *str);
+int set_new_password(const char *password_type, const char *new_password);
+int init_bios_attr_pass_interface(void);
+void exit_bios_attr_pass_interface(void);
+void *ascii_to_utf16_unicode(u16 *p, const u8 *str);
+int get_integer_from_buffer(int **buffer, int *integer);
+int get_string_from_buffer(u16 **buffer, char **str);
+int convert_hexstr_to_str(char **hex, int input_len, char **str, int *len);
+int convert_hexstr_to_int(char *str, int *int_value);
+inline int encode_outsize_for_pvsz(int outsize);
+
+#endif
diff --git a/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
new file mode 100644
index 000000000000..e67e7c397c12
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/enum-attributes.c
@@ -0,0 +1,521 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to enumeration type attributes under
+ * BIOS Enumeration GUID for use with hp-bioscfg driver.
+ *
+ *  Copyright (c) 2022 HP Development Company, L.P.
+ */
+
+#include "bioscfg.h"
+
+get_instance_id(enumeration);
+
+static ssize_t current_value_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	int instance_id = get_enumeration_instance_id(kobj);
+	union acpi_object *obj = NULL;
+	ssize_t ret;
+
+	if (instance_id < 0)
+		return -EIO;
+
+	/* need to use specific instance_id and guid combination to get right data */
+	obj = get_wmiobj_pointer(instance_id, HP_WMI_BIOS_ENUMERATION_GUID);
+	if (!obj)
+		return -EIO;
+
+	ret = snprintf(buf, PAGE_SIZE, "%s\n",
+		       bioscfg_drv.enumeration_data[instance_id].current_value);
+
+	kfree(obj);
+	return ret;
+}
+
+
+/*
+ * validate_enumeration_input() -
+ * Validate input of current_value against possible values
+ *
+ * @instance_id: The instance on which input is validated
+ * @buf: Input value
+ */
+static int validate_enumeration_input(int instance_id, const char *buf)
+{
+	char *options = NULL;
+	char *p;
+	int ret = 0;
+	int found = 0;
+
+	options = kstrdup(bioscfg_drv.enumeration_data[instance_id].possible_values,
+			  GFP_KERNEL);
+
+	if (!options) {
+		ret = -ENOMEM;
+		goto exit_validate_enum_input;
+	}
+
+	/* Is it a read only attribute */
+	if (bioscfg_drv.enumeration_data[instance_id].is_readonly) {
+		ret = -EIO;
+		goto exit_validate_enum_input;
+	}
+
+	while ((p = strsep(&options, ";")) != NULL) {
+		if (!*p)
+			continue;
+
+		if (!strcasecmp(p, buf)) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		ret = -EINVAL;
+		goto exit_validate_enum_input;
+	}
+
+	strscpy(bioscfg_drv.enumeration_data[instance_id].new_value,
+		buf,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].new_value));
+	/*
+	 * set pending reboot flag depending on
+	 * "RequiresPhysicalPresence" value
+	 */
+	if (bioscfg_drv.enumeration_data[instance_id].requires_physical_presence)
+		bioscfg_drv.pending_reboot = TRUE;
+
+exit_validate_enum_input:
+	kfree(options);
+	return ret;
+}
+
+static void update_enumeration_value(int instance_id)
+{
+	strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
+		bioscfg_drv.enumeration_data[instance_id].new_value,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
+}
+
+
+attribute_s_property_show(display_name_language_code, enumeration);
+static struct kobj_attribute enumeration_display_langcode =
+		__ATTR_RO(display_name_language_code);
+
+attribute_s_property_show(display_name, enumeration);
+static struct kobj_attribute  enumeration_display_name =
+		__ATTR_RO(display_name);
+
+attribute_property_store(current_value, enumeration);
+static struct kobj_attribute enumeration_current_val =
+	__ATTR_RW_MODE(current_value, 0600);
+
+attribute_s_property_show(possible_values, enumeration);
+static struct kobj_attribute  enumeration_poss_val =
+		__ATTR_RO(possible_values);
+
+static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	return sprintf(buf, "enumeration\n");
+}
+static struct kobj_attribute enumeration_type =
+		__ATTR_RO(type);
+
+static struct attribute *enumeration_attrs[] = {
+	&enumeration_display_langcode.attr,
+	&enumeration_display_name.attr,
+	&enumeration_current_val.attr,
+	&enumeration_poss_val.attr,
+	&enumeration_type.attr,
+	NULL,
+};
+
+static const struct attribute_group enumeration_attr_group = {
+	.attrs = enumeration_attrs,
+};
+
+int alloc_enumeration_data(void)
+{
+	int ret = 0;
+
+	bioscfg_drv.enumeration_instances_count =
+		get_instance_count(HP_WMI_BIOS_ENUMERATION_GUID);
+
+	bioscfg_drv.enumeration_data = kcalloc(bioscfg_drv.enumeration_instances_count,
+					sizeof(struct enumeration_data), GFP_KERNEL);
+	if (!bioscfg_drv.enumeration_data) {
+		bioscfg_drv.enumeration_instances_count = 0;
+		ret = -ENOMEM;
+	}
+	return ret;
+}
+
+/*
+ * populate_enumeration_package_data() -
+ * Populate all properties of an instance under enumeration attribute
+ *
+ * @enum_obj: ACPI object with enumeration data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int populate_enumeration_package_data(union acpi_object *enum_obj, int instance_id,
+			struct kobject *attr_name_kobj)
+{
+	char *str_value = NULL;
+	int str_len;
+	int ret = 0;
+
+	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
+	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
+
+	ret = convert_hexstr_to_str(&(enum_obj[NAME].string.pointer),
+				    enum_obj[NAME].string.length,
+				    &str_value, &str_len);
+	if (ACPI_FAILURE(ret)) {
+		pr_warn("Failed to populate enumeration package data. Error [0%0x]\n", ret);
+		kfree(str_value);
+		return ret;
+	}
+
+	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
+		str_value,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
+
+	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
+		str_value,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
+
+	kfree(str_value);
+	str_value = NULL;
+
+	populate_enumeration_elements_from_package(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
+	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
+				    &enumeration_current_val);
+	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
+				  attr_name_kobj->name,
+				   bioscfg_drv.enumeration_data[instance_id].display_name,
+				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
+	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
+}
+
+int populate_enumeration_elements_from_package(union acpi_object *enum_obj,
+					   int instance_id,
+					   enum hp_wmi_data_type type)
+{
+	char *str_value = NULL;
+	int value_len;
+	int status = 0;
+	u32 size = 0;
+	u32 int_value;
+	int elem = 0;
+	int reqs;
+	int eloc;
+	int pos_values;
+
+	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
+		LANG_CODE_STR,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
+
+	for (elem = 1, eloc = 1; elem < hp_wmi_elements_count[type]; elem++, eloc++) {
+
+		switch (enum_obj[elem].type) {
+		case ACPI_TYPE_STRING:
+
+			if (PREREQUISITES != elem && ENUM_POSSIBLE_VALUES != elem) {
+				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
+							       enum_obj[elem].string.length,
+							       &str_value, &value_len);
+				if (ACPI_FAILURE(status))
+					continue;
+
+			}
+			break;
+		case ACPI_TYPE_INTEGER:
+			int_value = (u32)enum_obj[elem].integer.value;
+			break;
+		default:
+			pr_warn("Unsupported object type [%d]\n", enum_obj[elem].type);
+			continue;
+		}
+
+		/* stop if extra counter is greater than total number
+		 * of elements for enumeration type
+		 */
+		if (eloc == hp_wmi_elements_count[type])
+			goto exit_enumeration_package;
+
+		/* Assign appropriate element value to corresponding field*/
+		switch (eloc) {
+		case VALUE:
+			break;
+		case PATH:
+			strscpy(bioscfg_drv.enumeration_data[instance_id].path, str_value,
+				sizeof(bioscfg_drv.enumeration_data[instance_id].path));
+			break;
+		case IS_READONLY:
+			bioscfg_drv.enumeration_data[instance_id].is_readonly = int_value;
+			break;
+		case DISPLAY_IN_UI:
+			bioscfg_drv.enumeration_data[instance_id].display_in_ui = int_value;
+			break;
+		case REQUIRES_PHYSICAL_PRESENCE:
+			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = int_value;
+			break;
+		case SEQUENCE:
+			bioscfg_drv.enumeration_data[instance_id].sequence = int_value;
+			break;
+		case PREREQUISITE_SIZE:
+			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = int_value;
+			if (int_value > 20)
+				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
+			/*
+			 * prerequisites element is omitted when
+			 * prerequisitesSize value is zero.
+			 */
+			if (int_value == 0)
+				eloc++;
+			break;
+		case PREREQUISITES:
+			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
+
+			for (reqs = 0; reqs < size; reqs++) {
+				status = convert_hexstr_to_str(&enum_obj[elem].string.pointer,
+							       enum_obj[elem].string.length,
+							       &str_value, &value_len);
+				if (ACPI_FAILURE(status))
+					break;
+
+				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
+					str_value,
+					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
+				if (reqs != (size - 1))
+					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
+						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
+
+				kfree(str_value);
+				str_value = NULL;
+			}
+			break;
+
+		case SECURITY_LEVEL:
+			bioscfg_drv.enumeration_data[instance_id].security_level = int_value;
+			break;
+
+		case ENUM_CURRENT_VALUE:
+			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
+				str_value, sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
+			break;
+		case ENUM_SIZE:
+			bioscfg_drv.enumeration_data[instance_id].size = int_value;
+			break;
+		case ENUM_POSSIBLE_VALUES:
+			size = bioscfg_drv.enumeration_data[instance_id].size;
+			for (pos_values = 0; pos_values < size; pos_values++) {
+				status = convert_hexstr_to_str(&enum_obj[elem + pos_values].string.pointer,
+							       enum_obj[elem  + pos_values].string.length,
+							       &str_value, &value_len);
+				if (ACPI_FAILURE(status))
+					break;
+
+				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
+					str_value,
+					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
+				if (pos_values < (size - 1))
+					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
+						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
+				kfree(str_value);
+				str_value = NULL;
+			}
+			break;
+		default:
+			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
+			break;
+		}
+
+		kfree(str_value);
+		str_value = NULL;
+	}
+
+exit_enumeration_package:
+		kfree(str_value);
+		str_value = NULL;
+	return 0;
+}
+
+/*
+ * populate_enumeration_buffer_data() -
+ * Populate all properties of an instance under enumeration attribute
+ *
+ * @enum_obj: ACPI object with enumeration data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ * @enumeration_property_count: Total properties count under enumeration type
+ */
+int populate_enumeration_buffer_data(union acpi_object *enum_obj, int instance_id,
+			      struct kobject *attr_name_kobj)
+{
+
+	bioscfg_drv.enumeration_data[instance_id].type = HPWMI_ENUMERATION_TYPE;
+	bioscfg_drv.enumeration_data[instance_id].attr_name_kobj = attr_name_kobj;
+	strscpy(bioscfg_drv.enumeration_data[instance_id].attribute_name,
+		attr_name_kobj->name,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].attribute_name));
+	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name,
+		attr_name_kobj->name,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
+
+	/* Populate enumeration elements */
+	populate_enumeration_elements_from_buffer(enum_obj, instance_id, HPWMI_ENUMERATION_TYPE);
+	update_attribute_permissions(bioscfg_drv.enumeration_data[instance_id].is_readonly,
+				    &enumeration_current_val);
+	friendly_user_name_update(bioscfg_drv.enumeration_data[instance_id].path,
+				  attr_name_kobj->name,
+				   bioscfg_drv.enumeration_data[instance_id].display_name,
+				   sizeof(bioscfg_drv.enumeration_data[instance_id].display_name));
+
+	return sysfs_create_group(attr_name_kobj, &enumeration_attr_group);
+}
+
+int populate_enumeration_elements_from_buffer(union acpi_object *enum_obj,
+					      int instance_id,
+					      enum hp_wmi_data_type type)
+{
+	int status;
+	char *str = NULL;
+	int elem;
+	int reqs;
+	int integer;
+	int size = 0;
+	int values;
+
+	elem = 0;
+
+	strscpy(bioscfg_drv.enumeration_data[instance_id].display_name_language_code,
+		LANG_CODE_STR,
+		sizeof(bioscfg_drv.enumeration_data[instance_id].display_name_language_code));
+
+	for (elem = 1; elem < 3; elem++) {
+
+		status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
+		if (ACPI_FAILURE(status))
+			continue;
+
+		switch (elem) {
+		case VALUE:
+			/* Skip 'Value' since 'CurrentValue' is reported. */
+			break;
+		case PATH:
+			strscpy(bioscfg_drv.enumeration_data[instance_id].path,
+				str, sizeof(bioscfg_drv.enumeration_data[instance_id].path));
+			break;
+		default:
+			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
+			break;
+		}
+		kfree(str);
+		str = NULL;
+	}
+
+	for (elem = 3; elem < hp_wmi_elements_count[type]; elem++) {
+		if (PREREQUISITES != elem && ENUM_CURRENT_VALUE != elem && ENUM_POSSIBLE_VALUES != elem)
+			status = get_integer_from_buffer((int **)&enum_obj->buffer.pointer, (int *)&integer);
+
+		if (ACPI_FAILURE(status))
+			continue;
+		switch (elem) {
+		case IS_READONLY:
+			bioscfg_drv.enumeration_data[instance_id].is_readonly = integer;
+			break;
+		case DISPLAY_IN_UI:
+			bioscfg_drv.enumeration_data[instance_id].display_in_ui = integer;
+			break;
+		case REQUIRES_PHYSICAL_PRESENCE:
+			bioscfg_drv.enumeration_data[instance_id].requires_physical_presence = integer;
+			break;
+		case SEQUENCE:
+			bioscfg_drv.enumeration_data[instance_id].sequence = integer;
+			break;
+		case PREREQUISITE_SIZE:
+			bioscfg_drv.enumeration_data[instance_id].prerequisitesize = integer;
+			if (integer > 20)
+				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
+			break;
+		case PREREQUISITES:
+			size = bioscfg_drv.enumeration_data[instance_id].prerequisitesize;
+			for (reqs = 0; reqs < size; reqs++) {
+				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
+				if (ACPI_FAILURE(status))
+					continue;
+
+				strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites,
+					str,
+					sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
+				if (reqs != (size - 1))
+					strlcat(bioscfg_drv.enumeration_data[instance_id].prerequisites, ";",
+						sizeof(bioscfg_drv.enumeration_data[instance_id].prerequisites));
+				kfree(str);
+				str = NULL;
+			}
+			break;
+		case SECURITY_LEVEL:
+			bioscfg_drv.enumeration_data[instance_id].security_level = integer;
+			break;
+		case ENUM_CURRENT_VALUE:
+			status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
+			strscpy(bioscfg_drv.enumeration_data[instance_id].current_value,
+				str,
+				sizeof(bioscfg_drv.enumeration_data[instance_id].current_value));
+			break;
+		case ENUM_SIZE:
+			bioscfg_drv.enumeration_data[instance_id].size = integer;
+			break;
+		case ENUM_POSSIBLE_VALUES:
+			size = bioscfg_drv.enumeration_data[instance_id].size;
+			for (values = 0; values < size; values++) {
+				status = get_string_from_buffer((u16 **)&enum_obj->buffer.pointer, &str);
+				if (ACPI_FAILURE(status))
+					continue;
+
+				strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values,
+					str,
+					sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
+				if (values != (size - 1))
+					strlcat(bioscfg_drv.enumeration_data[instance_id].possible_values, ";",
+						sizeof(bioscfg_drv.enumeration_data[instance_id].possible_values));
+				kfree(str);
+				str = NULL;
+			}
+			break;
+		default:
+			pr_warn("Invalid element: %d found in Enumeration attribute or data may be malformed\n", elem);
+			break;
+		}
+		kfree(str);
+		str = NULL;
+	}
+	kfree(str);
+	str = NULL;
+
+	return 0;
+}
+
+/**
+ * exit_enumeration_attributes() - Clear all attribute data
+ *
+ * Clears all data allocated for this group of attributes
+ */
+void exit_enumeration_attributes(void)
+{
+	int instance_id;
+
+	for (instance_id = 0; instance_id < bioscfg_drv.enumeration_instances_count; instance_id++) {
+		if (bioscfg_drv.enumeration_data[instance_id].attr_name_kobj)
+			sysfs_remove_group(bioscfg_drv.enumeration_data[instance_id].attr_name_kobj,
+								&enumeration_attr_group);
+	}
+	bioscfg_drv.enumeration_instances_count = 0;
+
+	kfree(bioscfg_drv.enumeration_data);
+	bioscfg_drv.enumeration_data = NULL;
+}