cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

passwordattr-interface.c (4382B)

      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);