drivers/platform/x86/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
  11 static 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  */
  41 int 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         /* clear current_password here and use user input from wmi_priv.current_password */
  99         if (!ret)
 100                 memset(current_password, 0, 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
 107 out:
 108         kfree(buffer);
 109         mutex_unlock(&wmi_priv.mutex);
 110
 111         return ret;
 112 }
 113
 114 static 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
 122 static int 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         return 0;
 128 }
 129
 130 static const struct wmi_device_id bios_attr_pass_interface_id_table[] = {
 131         { .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
 132         { },
 133 };
 134 static struct wmi_driver bios_attr_pass_interface_driver = {
 135         .driver = {
 136                 .name = DRIVER_NAME"-password"
 137         },
 138         .probe = bios_attr_pass_interface_probe,
 139         .remove = bios_attr_pass_interface_remove,
 140         .id_table = bios_attr_pass_interface_id_table,
 141 };
 142
 143 int init_bios_attr_pass_interface(void)
 144 {
 145         return wmi_driver_register(&bios_attr_pass_interface_driver);
 146 }
 147
 148 void exit_bios_attr_pass_interface(void)
 149 {
 150         wmi_driver_unregister(&bios_attr_pass_interface_driver);
 151 }
 152
 153 MODULE_DEVICE_TABLE(wmi, bios_attr_pass_interface_id_table);