[PATCH v17 08/13] hp-bioscfg: passwdobj-attributes

[Jorge Lopez]

Add authentication attributes support to hp-bioscfg.

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.

Signed-off-by: Jorge Lopez <jorge.lopez2@xxxxxx>

---
Based on the latest platform-drivers-x86.git/for-next
---
 .../x86/hp/hp-bioscfg/passwdobj-attributes.c  | 543 ++++++++++++++++++
 1 file changed, 543 insertions(+)
 create mode 100644 drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c

diff --git a/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c
new file mode 100644
index 000000000000..52e4d346b529
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/passwdobj-attributes.c
@@ -0,0 +1,543 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to password object type attributes under
+ * BIOS PASSWORD for use with hp-bioscfg driver.
+ *
+ * Copyright (c) 2022 HP Development Company, L.P.
+ */
+
+#include "bioscfg.h"
+#include <asm-generic/posix_types.h>
+
+GET_INSTANCE_ID(password);
+/*
+ * Clear all passwords copied to memory for a particular
+ * authentication instance
+ */
+static int clear_passwords(const int instance)
+{
+	struct password_data *password_data = &bioscfg_drv.password_data[instance];
+
+	if (!password_data->is_enabled)
+		return 0;
+
+	memset(password_data->current_password,
+	       0, sizeof(password_data->current_password));
+	memset(password_data->new_password,
+	       0, sizeof(password_data->new_password));
+
+	return 0;
+}
+
+/*
+ * Clear all credentials copied to memory for both Power-ON and Setup
+ * BIOS instances
+ */
+int hp_clear_all_credentials(void)
+{
+	int count = bioscfg_drv.password_instances_count;
+	int instance;
+
+	/* clear all passwords */
+	for (instance = 0; instance < count; instance++)
+		clear_passwords(instance);
+
+	/* clear auth_token */
+	kfree(bioscfg_drv.spm_data.auth_token);
+	bioscfg_drv.spm_data.auth_token = NULL;
+
+	return 0;
+}
+
+int hp_get_password_instance_for_type(const char *name)
+{
+	int count = bioscfg_drv.password_instances_count;
+	int instance;
+
+	for (instance = 0; instance < count; instance++)
+		if (!strcmp(bioscfg_drv.password_data[instance].common.display_name, name))
+			return instance;
+
+	return -EINVAL;
+}
+
+static int validate_password_input(int instance_id, const char *buf)
+{
+	int length;
+	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
+
+	length = strlen(buf);
+	if (buf[length - 1] == '\n')
+		length--;
+
+	if (length > MAX_PASSWD_SIZE)
+		return INVALID_BIOS_AUTH;
+
+	if (password_data->min_password_length > length ||
+	    password_data->max_password_length < length)
+		return INVALID_BIOS_AUTH;
+	return SUCCESS;
+}
+
+ATTRIBUTE_N_PROPERTY_SHOW(is_enabled, password);
+static struct kobj_attribute password_is_password_set = __ATTR_RO(is_enabled);
+
+static int store_password_instance(struct kobject *kobj, const char *buf,
+				   size_t count, bool is_current)
+{
+	char *buf_cp;
+	int id, ret = 0;
+
+	buf_cp = kstrdup(buf, GFP_KERNEL);
+	if (!buf_cp)
+		return -ENOMEM;
+
+	ret = hp_enforce_single_line_input(buf_cp, count);
+	if (!ret) {
+		id = get_password_instance_id(kobj);
+
+		if (id >= 0)
+			ret = validate_password_input(id, buf_cp);
+	}
+
+	if (!ret) {
+		if (is_current)
+			strscpy(bioscfg_drv.password_data[id].current_password,
+				buf_cp,
+				sizeof(bioscfg_drv.password_data[id].current_password));
+		else
+			strscpy(bioscfg_drv.password_data[id].new_password,
+				buf_cp,
+				sizeof(bioscfg_drv.password_data[id].new_password));
+	}
+
+	kfree(buf_cp);
+	return ret < 0 ? ret : count;
+}
+
+static ssize_t current_password_store(struct kobject *kobj,
+				      struct kobj_attribute *attr,
+				      const char *buf, size_t count)
+{
+	return store_password_instance(kobj, buf, count, true);
+}
+
+static struct kobj_attribute password_current_password = __ATTR_WO(current_password);
+
+static ssize_t new_password_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t count)
+{
+	return store_password_instance(kobj, buf, count, true);
+}
+
+static struct kobj_attribute password_new_password = __ATTR_WO(new_password);
+
+ATTRIBUTE_N_PROPERTY_SHOW(min_password_length, password);
+static struct kobj_attribute password_min_password_length = __ATTR_RO(min_password_length);
+
+ATTRIBUTE_N_PROPERTY_SHOW(max_password_length, password);
+static struct kobj_attribute password_max_password_length = __ATTR_RO(max_password_length);
+
+static ssize_t role_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	if (!strcmp(kobj->name, SETUP_PASSWD))
+		return sysfs_emit(buf, "%s\n", BIOS_ADMIN);
+
+	if (!strcmp(kobj->name, POWER_ON_PASSWD))
+		return sysfs_emit(buf, "%s\n", POWER_ON);
+
+	return -EIO;
+}
+
+static struct kobj_attribute password_role = __ATTR_RO(role);
+
+static ssize_t mechanism_show(struct kobject *kobj, struct kobj_attribute *attr,
+			      char *buf)
+{
+	int i = get_password_instance_id(kobj);
+
+	if (i < 0)
+		return i;
+
+	if (bioscfg_drv.password_data[i].mechanism != PASSWORD)
+		return -EINVAL;
+
+	return sysfs_emit(buf, "%s\n", PASSWD_MECHANISM_TYPES);
+}
+
+static struct kobj_attribute password_mechanism = __ATTR_RO(mechanism);
+
+ATTRIBUTE_VALUES_PROPERTY_SHOW(encodings, password, SEMICOLON_SEP);
+static struct kobj_attribute password_encodings_val = __ATTR_RO(encodings);
+
+static struct attribute *password_attrs[] = {
+	&password_is_password_set.attr,
+	&password_min_password_length.attr,
+	&password_max_password_length.attr,
+	&password_current_password.attr,
+	&password_new_password.attr,
+	&password_role.attr,
+	&password_mechanism.attr,
+	&password_encodings_val.attr,
+	NULL
+};
+
+static const struct attribute_group password_attr_group = {
+	.attrs = password_attrs
+};
+
+int hp_alloc_password_data(void)
+{
+	bioscfg_drv.password_instances_count = hp_get_instance_count(HP_WMI_BIOS_PASSWORD_GUID);
+	bioscfg_drv.password_data = kcalloc(bioscfg_drv.password_instances_count,
+					    sizeof(*bioscfg_drv.password_data), GFP_KERNEL);
+	if (!bioscfg_drv.password_data) {
+		bioscfg_drv.password_instances_count = 0;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/* Expected Values types associated with each element */
+static const acpi_object_type expected_password_types[] = {
+	[NAME] = ACPI_TYPE_STRING,
+	[VALUE] = ACPI_TYPE_STRING,
+	[PATH] = ACPI_TYPE_STRING,
+	[IS_READONLY] = ACPI_TYPE_INTEGER,
+	[DISPLAY_IN_UI] = ACPI_TYPE_INTEGER,
+	[REQUIRES_PHYSICAL_PRESENCE] = ACPI_TYPE_INTEGER,
+	[SEQUENCE] = ACPI_TYPE_INTEGER,
+	[PREREQUISITES_SIZE] = ACPI_TYPE_INTEGER,
+	[PREREQUISITES] = ACPI_TYPE_STRING,
+	[SECURITY_LEVEL] = ACPI_TYPE_INTEGER,
+	[PSWD_MIN_LENGTH] = ACPI_TYPE_INTEGER,
+	[PSWD_MAX_LENGTH] = ACPI_TYPE_INTEGER,
+	[PSWD_SIZE] = ACPI_TYPE_INTEGER,
+	[PSWD_ENCODINGS] = ACPI_TYPE_STRING,
+	[PSWD_IS_SET] = ACPI_TYPE_INTEGER,
+};
+
+static int hp_populate_password_elements_from_package(union acpi_object *password_obj,
+						      int password_obj_count,
+						      int instance_id)
+{
+	char *str_value = NULL;
+	int value_len;
+	int ret;
+	u32 size;
+	u32 int_value;
+	int elem;
+	int reqs;
+	int eloc;
+	int pos_values;
+	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
+
+	if (!password_obj)
+		return -EINVAL;
+
+	for (elem = 1, eloc = 1; elem < password_obj_count; elem++, eloc++) {
+		/* ONLY look at the first PASSWORD_ELEM_CNT elements */
+		if (eloc == PSWD_ELEM_CNT)
+			goto exit_package;
+
+		switch (password_obj[elem].type) {
+		case ACPI_TYPE_STRING:
+			if (PREREQUISITES != elem && PSWD_ENCODINGS != elem) {
+				ret = hp_convert_hexstr_to_str(password_obj[elem].string.pointer,
+							       password_obj[elem].string.length,
+							       &str_value, &value_len);
+				if (ret)
+					continue;
+			}
+			break;
+		case ACPI_TYPE_INTEGER:
+			int_value = (u32)password_obj[elem].integer.value;
+			break;
+		default:
+			pr_warn("Unsupported object type [%d]\n", password_obj[elem].type);
+			continue;
+		}
+
+		/* Check that both expected and read object type match */
+		if (expected_password_types[eloc] != password_obj[elem].type) {
+			pr_err("Error expected type %d for elem %d, but got type %d instead\n",
+			       expected_password_types[eloc], elem, password_obj[elem].type);
+			return -EIO;
+		}
+
+		/* Assign appropriate element value to corresponding field*/
+		switch (eloc) {
+		case VALUE:
+			break;
+		case PATH:
+			strscpy(password_data->common.path, str_value,
+				sizeof(password_data->common.path));
+			break;
+		case IS_READONLY:
+			password_data->common.is_readonly = int_value;
+			break;
+		case DISPLAY_IN_UI:
+			password_data->common.display_in_ui = int_value;
+			break;
+		case REQUIRES_PHYSICAL_PRESENCE:
+			password_data->common.requires_physical_presence = int_value;
+			break;
+		case SEQUENCE:
+			password_data->common.sequence = int_value;
+			break;
+		case PREREQUISITES_SIZE:
+			password_data->common.prerequisites_size = int_value;
+			if (int_value > MAX_PREREQUISITES_SIZE)
+				pr_warn("Prerequisites size value exceeded the maximum number of elements supported or data may be malformed\n");
+
+			/* This HACK is needed to keep the expected
+			 * element list pointing to the right obj[elem].type
+			 * when the size is zero. PREREQUISITES
+			 * object is omitted by BIOS when the size is
+			 * zero.
+			 */
+			if (int_value == 0)
+				eloc++;
+			break;
+		case PREREQUISITES:
+			size = min_t(u32, password_data->common.prerequisites_size,
+				     MAX_PREREQUISITES_SIZE);
+
+			for (reqs = 0; reqs < size; reqs++) {
+				ret = hp_convert_hexstr_to_str(password_obj[elem + reqs].string.pointer,
+							       password_obj[elem + reqs].string.length,
+							       &str_value, &value_len);
+
+				if (ret)
+					break;
+
+				strscpy(password_data->common.prerequisites[reqs],
+					str_value,
+					sizeof(password_data->common.prerequisites[reqs]));
+
+				kfree(str_value);
+			}
+			break;
+		case SECURITY_LEVEL:
+			password_data->common.security_level = int_value;
+			break;
+		case PSWD_MIN_LENGTH:
+			password_data->min_password_length = int_value;
+			break;
+		case PSWD_MAX_LENGTH:
+			password_data->max_password_length = int_value;
+			break;
+		case PSWD_SIZE:
+			password_data->encodings_size = int_value;
+			if (int_value > MAX_ENCODINGS_SIZE)
+				pr_warn("Password Encoding size value exceeded the maximum number of elements supported or data may be malformed\n");
+
+			/* This HACK is needed to keep the expected
+			 * element list pointing to the right obj[elem].type
+			 * when the size is zero. PSWD_ENCODINGS
+			 * object is omitted by BIOS when the size is
+			 * zero.
+			 */
+			if (int_value == 0)
+				eloc++;
+			break;
+		case PSWD_ENCODINGS:
+			size = min_t(u32, password_data->encodings_size, MAX_ENCODINGS_SIZE);
+			for (pos_values = 0; pos_values < size; pos_values++) {
+				ret = hp_convert_hexstr_to_str(password_obj[elem + pos_values].string.pointer,
+							       password_obj[elem + pos_values].string.length,
+							       &str_value, &value_len);
+				if (ret)
+					break;
+
+				strscpy(password_data->encodings[pos_values],
+					str_value,
+					sizeof(password_data->encodings[pos_values]));
+				kfree(str_value);
+			}
+			break;
+		case PSWD_IS_SET:
+			password_data->is_enabled = int_value;
+			break;
+		default:
+			pr_warn("Invalid element: %d found in Password attribute or data may be malformed\n", elem);
+			break;
+		}
+	}
+
+exit_package:
+	kfree(str_value);
+	return 0;
+}
+
+/**
+ * hp_populate_password_package_data()
+ *	Populate all properties for an instance under password attribute
+ *
+ * @password_obj: ACPI object with password data
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int hp_populate_password_package_data(union acpi_object *password_obj, int instance_id,
+				      struct kobject *attr_name_kobj)
+{
+	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
+
+	password_data->attr_name_kobj = attr_name_kobj;
+
+	hp_populate_password_elements_from_package(password_obj,
+						   password_obj->package.count,
+						   instance_id);
+
+	hp_friendly_user_name_update(password_data->common.path,
+				     attr_name_kobj->name,
+				     password_data->common.display_name,
+				     sizeof(password_data->common.display_name));
+
+	if (!strcmp(attr_name_kobj->name, SETUP_PASSWD))
+		return sysfs_create_group(attr_name_kobj, &password_attr_group);
+
+	return sysfs_create_group(attr_name_kobj, &password_attr_group);
+}
+
+static int hp_populate_password_elements_from_buffer(u8 *buffer_ptr, u32 *buffer_size,
+						     int instance_id)
+{
+	int values;
+	int isreadonly;
+	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
+	int ret = 0;
+
+	/*
+	 * Only data relevant to this driver and its functionality is
+	 * read. BIOS defines the order in which each * element is
+	 * read. Element 0 data is not relevant to this
+	 * driver hence it is ignored. For clarity, all element names
+	 * (DISPLAY_IN_UI) which defines the order in which is read
+	 * and the name matches the variable where the data is stored.
+	 *
+	 * In earlier implementation, reported errors were ignored
+	 * causing the data to remain uninitialized. It is not
+	 * possible to determine if data read from BIOS is valid or
+	 * not. It is for this reason functions may return a error
+	 * without validating the data itself.
+	 */
+
+	// VALUE:
+	ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size, password_data->current_password,
+					sizeof(password_data->current_password));
+	if (ret < 0)
+		goto buffer_exit;
+
+	// COMMON:
+	ret = hp_get_common_data_from_buffer(&buffer_ptr, buffer_size,
+					     &password_data->common);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// PSWD_MIN_LENGTH:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &password_data->min_password_length);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// PSWD_MAX_LENGTH:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &password_data->max_password_length);
+	if (ret < 0)
+		goto buffer_exit;
+
+	// PSWD_SIZE:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size,
+					 &password_data->encodings_size);
+	if (ret < 0)
+		goto buffer_exit;
+
+	if (password_data->encodings_size > MAX_ENCODINGS_SIZE) {
+		/* Report a message and limit possible values size to maximum value */
+		pr_warn("Password Encoding size value exceeded the maximum number of elements supported or data may be malformed\n");
+		password_data->encodings_size = MAX_ENCODINGS_SIZE;
+	}
+
+	// PSWD_ENCODINGS:
+	for (values = 0; values < password_data->encodings_size; values++) {
+		ret = hp_get_string_from_buffer(&buffer_ptr, buffer_size,
+						password_data->encodings[values],
+						sizeof(password_data->encodings[values]));
+		if (ret < 0)
+			break;
+	}
+
+	// PSWD_IS_SET:
+	ret = hp_get_integer_from_buffer(&buffer_ptr, buffer_size, &isreadonly);
+	if (ret < 0)
+		goto buffer_exit;
+
+	password_data->is_enabled = isreadonly ? true : false;
+
+buffer_exit:
+	return ret;
+}
+
+/**
+ * hp_populate_password_buffer_data()
+ * Populate all properties for an instance under password object attribute
+ *
+ * @buffer_ptr: Buffer pointer
+ * @buffer_size: Buffer size
+ * @instance_id: The instance to enumerate
+ * @attr_name_kobj: The parent kernel object
+ */
+int hp_populate_password_buffer_data(u8 *buffer_ptr, u32 *buffer_size, int instance_id,
+				     struct kobject *attr_name_kobj)
+{
+	struct password_data *password_data = &bioscfg_drv.password_data[instance_id];
+	int ret = 0;
+
+	password_data->attr_name_kobj = attr_name_kobj;
+
+	/* Populate Password attributes */
+	ret = hp_populate_password_elements_from_buffer(buffer_ptr, buffer_size,
+							instance_id);
+	if (ret < 0)
+		return ret;
+
+	hp_friendly_user_name_update(password_data->common.path,
+				     attr_name_kobj->name,
+				     password_data->common.display_name,
+				     sizeof(password_data->common.display_name));
+	if (!strcmp(attr_name_kobj->name, SETUP_PASSWD))
+		return sysfs_create_group(attr_name_kobj, &password_attr_group);
+
+	return sysfs_create_group(attr_name_kobj, &password_attr_group);
+}
+
+/**
+ * hp_exit_password_attributes() - Clear all attribute data
+ *
+ * Clears all data allocated for this group of attributes
+ */
+void hp_exit_password_attributes(void)
+{
+	int instance_id;
+
+	for (instance_id = 0; instance_id < bioscfg_drv.password_instances_count;
+	     instance_id++) {
+		struct kobject *attr_name_kobj =
+			bioscfg_drv.password_data[instance_id].attr_name_kobj;
+
+		if (attr_name_kobj) {
+			if (!strcmp(attr_name_kobj->name, SETUP_PASSWD))
+				sysfs_remove_group(attr_name_kobj,
+						   &password_attr_group);
+			else
+				sysfs_remove_group(attr_name_kobj,
+						   &password_attr_group);
+		}
+	}
+	bioscfg_drv.password_instances_count = 0;
+	kfree(bioscfg_drv.password_data);
+	bioscfg_drv.password_data = NULL;
+}
-- 
2.34.1