LXR linux/drivers/platform/x86/dell/dell-wmi-sysman/passwordattr-interface.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Functions corresponding to SET password methods under BIOS attributes interface GUID
   4 *
   5 *  Copyright (c) 2020 Dell Inc.
   6 */
   7
   8#include <linux/wmi.h>
   9#include "dell-wmi-sysman.h"
  10
  11static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
  12{
  13        struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
  14        struct acpi_buffer input;
  15        union acpi_object *obj;
  16        acpi_status status;
  17        int ret = -EIO;
  18
  19        input.length =  (acpi_size) size;
  20        input.pointer = in_args;
  21        status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
  22        if (ACPI_FAILURE(status))
  23                return -EIO;
  24        obj = (union acpi_object *)output.pointer;
  25        if (obj->type == ACPI_TYPE_INTEGER)
  26                ret = obj->integer.value;
  27
  28        kfree(output.pointer);
  29        /* let userland know it may need to check is_password_set again */
  30        kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
  31        return map_wmi_error(ret);
  32}
  33
  34/**
  35 * set_new_password() - Sets a system admin password
  36 * @password_type: The type of password to set
  37 * @new: The new password
  38 *
  39 * Sets the password using plaintext interface
  40 */
  41int set_new_password(const char *password_type, const char *new)
  42{
  43        size_t password_type_size, current_password_size, new_size;
  44        size_t security_area_size, buffer_size;
  45        char *buffer = NULL, *start;
  46        char *current_password;
  47        int ret;
  48
  49        mutex_lock(&wmi_priv.mutex);
  50        if (!wmi_priv.password_attr_wdev) {
  51                ret = -ENODEV;
  52                goto out;
  53        }
  54        if (strcmp(password_type, "Admin") == 0) {
  55                current_password = wmi_priv.current_admin_password;
  56        } else if (strcmp(password_type, "System") == 0) {
  57                current_password = wmi_priv.current_system_password;
  58        } else {
  59                ret = -EINVAL;
  60                dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s\n",
  61                        password_type);
  62                goto out;
  63        }
  64
  65        /* build/calculate buffer */
  66        security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
  67        password_type_size = calculate_string_buffer(password_type);
  68        current_password_size = calculate_string_buffer(current_password);
  69        new_size = calculate_string_buffer(new);
  70        buffer_size = security_area_size + password_type_size + current_password_size + new_size;
  71        buffer = kzalloc(buffer_size, GFP_KERNEL);
  72        if (!buffer) {
  73                ret = -ENOMEM;
  74                goto out;
  75        }
  76
  77        /* build security area */
  78        populate_security_buffer(buffer, wmi_priv.current_admin_password);
  79
  80        /* build variables to set */
  81        start = buffer + security_area_size;
  82        ret = populate_string_buffer(start, password_type_size, password_type);
  83        if (ret < 0)
  84                goto out;
  85
  86        start += ret;
  87        ret = populate_string_buffer(start, current_password_size, current_password);
  88        if (ret < 0)
  89                goto out;
  90
  91        start += ret;
  92        ret = populate_string_buffer(start, new_size, new);
  93        if (ret < 0)
  94                goto out;
  95
  96        print_hex_dump_bytes("set new password data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
  97        ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
  98        /* on success copy the new password to current password */
  99        if (!ret)
 100                strscpy(current_password, new, MAX_BUFF);
 101        /* explain to user the detailed failure reason */
 102        else if (ret == -EOPNOTSUPP)
 103                dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured\n");
 104        else if (ret == -EACCES)
 105                dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password\n");
 106
 107out:
 108        kfree(buffer);
 109        mutex_unlock(&wmi_priv.mutex);
 110
 111        return ret;
 112}
 113
 114static int bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
 115{
 116        mutex_lock(&wmi_priv.mutex);
 117        wmi_priv.password_attr_wdev = wdev;
 118        mutex_unlock(&wmi_priv.mutex);
 119        return 0;
 120}
 121
 122static void bios_attr_pass_interface_remove(struct wmi_device *wdev)
 123{
 124        mutex_lock(&wmi_priv.mutex);
 125        wmi_priv.password_attr_wdev = NULL;
 126        mutex_unlock(&wmi_priv.mutex);
 127}
 128
 129static const struct wmi_device_id bios_attr_pass_interface_id_table[] = {
 130        { .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
 131        { },
 132};
 133static struct wmi_driver bios_attr_pass_interface_driver = {
 134        .driver = {
 135                .name = DRIVER_NAME"-password"
 136        },
 137        .probe = bios_attr_pass_interface_probe,
 138        .remove = bios_attr_pass_interface_remove,
 139        .id_table = bios_attr_pass_interface_id_table,
 140};
 141
 142int init_bios_attr_pass_interface(void)
 143{
 144        return wmi_driver_register(&bios_attr_pass_interface_driver);
 145}
 146
 147void exit_bios_attr_pass_interface(void)
 148{
 149        wmi_driver_unregister(&bios_attr_pass_interface_driver);
 150}
 151
 152MODULE_DEVICE_TABLE(wmi, bios_attr_pass_interface_id_table);
 153