153 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			153 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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/*
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 * Functions corresponding to SET password methods under BIOS attributes interface GUID
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 *
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 *  Copyright (c) 2020 Dell Inc.
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 */
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#include <linux/wmi.h>
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#include "dell-wmi-sysman.h"
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static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
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{
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	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
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	struct acpi_buffer input;
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	union acpi_object *obj;
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	acpi_status status;
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	int ret = -EIO;
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	input.length =  (acpi_size) size;
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	input.pointer = in_args;
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	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
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	if (ACPI_FAILURE(status))
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		return -EIO;
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	obj = (union acpi_object *)output.pointer;
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	if (obj->type == ACPI_TYPE_INTEGER)
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		ret = obj->integer.value;
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	kfree(output.pointer);
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	/* let userland know it may need to check is_password_set again */
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	kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
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	return map_wmi_error(ret);
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}
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/**
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 * set_new_password() - Sets a system admin password
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 * @password_type: The type of password to set
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 * @new: The new password
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 *
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 * Sets the password using plaintext interface
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 */
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int set_new_password(const char *password_type, const char *new)
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{
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	size_t password_type_size, current_password_size, new_size;
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	size_t security_area_size, buffer_size;
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	char *buffer = NULL, *start;
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	char *current_password;
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	int ret;
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	mutex_lock(&wmi_priv.mutex);
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	if (!wmi_priv.password_attr_wdev) {
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		ret = -ENODEV;
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		goto out;
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	}
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	if (strcmp(password_type, "Admin") == 0) {
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		current_password = wmi_priv.current_admin_password;
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	} else if (strcmp(password_type, "System") == 0) {
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		current_password = wmi_priv.current_system_password;
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	} else {
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		ret = -EINVAL;
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		dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s\n",
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			password_type);
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		goto out;
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	}
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	/* build/calculate buffer */
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	security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
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	password_type_size = calculate_string_buffer(password_type);
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	current_password_size = calculate_string_buffer(current_password);
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	new_size = calculate_string_buffer(new);
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	buffer_size = security_area_size + password_type_size + current_password_size + new_size;
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	buffer = kzalloc(buffer_size, GFP_KERNEL);
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	if (!buffer) {
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		ret = -ENOMEM;
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		goto out;
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	}
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	/* build security area */
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	populate_security_buffer(buffer, wmi_priv.current_admin_password);
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	/* build variables to set */
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	start = buffer + security_area_size;
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	ret = populate_string_buffer(start, password_type_size, password_type);
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	if (ret < 0)
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		goto out;
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	start += ret;
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	ret = populate_string_buffer(start, current_password_size, current_password);
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	if (ret < 0)
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		goto out;
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	start += ret;
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	ret = populate_string_buffer(start, new_size, new);
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	if (ret < 0)
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		goto out;
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	print_hex_dump_bytes("set new password data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
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	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
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	/* on success copy the new password to current password */
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	if (!ret)
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		strscpy(current_password, new, MAX_BUFF);
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	/* explain to user the detailed failure reason */
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	else if (ret == -EOPNOTSUPP)
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		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured\n");
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	else if (ret == -EACCES)
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		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password\n");
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out:
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	kfree(buffer);
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	mutex_unlock(&wmi_priv.mutex);
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	return ret;
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}
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static int bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
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{
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	mutex_lock(&wmi_priv.mutex);
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	wmi_priv.password_attr_wdev = wdev;
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	mutex_unlock(&wmi_priv.mutex);
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	return 0;
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}
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static void bios_attr_pass_interface_remove(struct wmi_device *wdev)
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{
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	mutex_lock(&wmi_priv.mutex);
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	wmi_priv.password_attr_wdev = NULL;
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	mutex_unlock(&wmi_priv.mutex);
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}
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static const struct wmi_device_id bios_attr_pass_interface_id_table[] = {
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	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
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	{ },
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};
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static struct wmi_driver bios_attr_pass_interface_driver = {
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	.driver = {
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		.name = DRIVER_NAME"-password"
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	},
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	.probe = bios_attr_pass_interface_probe,
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	.remove = bios_attr_pass_interface_remove,
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	.id_table = bios_attr_pass_interface_id_table,
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};
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int init_bios_attr_pass_interface(void)
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{
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	return wmi_driver_register(&bios_attr_pass_interface_driver);
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}
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void exit_bios_attr_pass_interface(void)
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{
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	wmi_driver_unregister(&bios_attr_pass_interface_driver);
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}
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MODULE_DEVICE_TABLE(wmi, bios_attr_pass_interface_id_table);
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