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