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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);