// SPDX-License-Identifier: GPL-2.0 /* * Common methods for use with dell-wmi-sysman * * Copyright (c) 2020 Dell Inc. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include "dell-wmi-sysman.h" #include "../../firmware_attributes_class.h" #define MAX_TYPES 4 #include struct wmi_sysman_priv wmi_priv = { .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex), }; /* reset bios to defaults */ static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"}; static int reset_option = -1; static struct class *fw_attr_class; /** * populate_string_buffer() - populates a string buffer * @buffer: the start of the destination buffer * @buffer_len: length of the destination buffer * @str: the string to insert into buffer */ ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str) { u16 *length = (u16 *)buffer; u16 *target = length + 1; int ret; ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN, target, buffer_len - sizeof(u16)); if (ret < 0) { dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n"); return ret; } if ((ret * sizeof(u16)) > U16_MAX) { dev_err(wmi_priv.class_dev, "Error string too long\n"); return -ERANGE; } *length = ret * sizeof(u16); return sizeof(u16) + *length; } /** * calculate_string_buffer() - determines size of string buffer for use with BIOS communication * @str: the string to calculate based upon * */ size_t calculate_string_buffer(const char *str) { /* u16 length field + one UTF16 char for each input char */ return sizeof(u16) + strlen(str) * sizeof(u16); } /** * calculate_security_buffer() - determines size of security buffer for authentication scheme * @authentication: the authentication content * * Currently only supported type is Admin password */ size_t calculate_security_buffer(char *authentication) { if (strlen(authentication) > 0) { return (sizeof(u32) * 2) + strlen(authentication) + strlen(authentication) % 2; } return sizeof(u32) * 2; } /** * populate_security_buffer() - builds a security buffer for authentication scheme * @buffer: the buffer to populate * @authentication: the authentication content * * Currently only supported type is PLAIN TEXT */ void populate_security_buffer(char *buffer, char *authentication) { char *auth = buffer + sizeof(u32) * 2; u32 *sectype = (u32 *) buffer; u32 *seclen = sectype + 1; *sectype = strlen(authentication) > 0 ? 1 : 0; *seclen = strlen(authentication); /* plain text */ if (strlen(authentication) > 0) memcpy(auth, authentication, *seclen); } /** * map_wmi_error() - map errors from WMI methods to kernel error codes * @error_code: integer error code returned from Dell's firmware */ int map_wmi_error(int error_code) { switch (error_code) { case 0: /* success */ return 0; case 1: /* failed */ return -EIO; case 2: /* invalid parameter */ return -EINVAL; case 3: /* access denied */ return -EACCES; case 4: /* not supported */ return -EOPNOTSUPP; case 5: /* memory error */ return -ENOMEM; case 6: /* protocol error */ return -EPROTO; } /* unspecified error */ return -EIO; } /** * reset_bios_show() - sysfs implementaton for read reset_bios * @kobj: Kernel object for this attribute * @attr: Kernel object attribute * @buf: The buffer to display to userspace */ static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { char *start = buf; int i; for (i = 0; i < MAX_TYPES; i++) { if (i == reset_option) buf += sprintf(buf, "[%s] ", reset_types[i]); else buf += sprintf(buf, "%s ", reset_types[i]); } buf += sprintf(buf, "\n"); return buf-start; } /** * reset_bios_store() - sysfs implementaton for write reset_bios * @kobj: Kernel object for this attribute * @attr: Kernel object attribute * @buf: The buffer from userspace * @count: the size of the buffer from userspace */ static ssize_t reset_bios_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int type = sysfs_match_string(reset_types, buf); int ret; if (type < 0) return type; ret = set_bios_defaults(type); pr_debug("reset all attributes request type %d: %d\n", type, ret); if (!ret) { reset_option = type; ret = count; } return ret; } /** * pending_reboot_show() - sysfs implementaton for read pending_reboot * @kobj: Kernel object for this attribute * @attr: Kernel object attribute * @buf: The buffer to display to userspace * * Stores default value as 0 * When current_value is changed this attribute is set to 1 to notify reboot may be required */ static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%d\n", wmi_priv.pending_changes); } static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios); static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot); /** * create_attributes_level_sysfs_files() - Creates reset_bios and * pending_reboot attributes */ static int create_attributes_level_sysfs_files(void) { int ret; ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); if (ret) return ret; ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); if (ret) return ret; return 0; } static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct kobj_attribute *kattr; ssize_t ret = -EIO; kattr = container_of(attr, struct kobj_attribute, attr); if (kattr->show) ret = kattr->show(kobj, kattr, buf); return ret; } static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct kobj_attribute *kattr; ssize_t ret = -EIO; kattr = container_of(attr, struct kobj_attribute, attr); if (kattr->store) ret = kattr->store(kobj, kattr, buf, count); return ret; } static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = { .show = wmi_sysman_attr_show, .store = wmi_sysman_attr_store, }; static void attr_name_release(struct kobject *kobj) { kfree(kobj); } static struct kobj_type attr_name_ktype = { .release = attr_name_release, .sysfs_ops = &wmi_sysman_kobj_sysfs_ops, }; /** * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks * @dest: Where to copy the string to * @src: Where to copy the string from */ void strlcpy_attr(char *dest, char *src) { size_t len = strlen(src) + 1; if (len > 1 && len <= MAX_BUFF) strlcpy(dest, src, len); /*len can be zero because any property not-applicable to attribute can * be empty so check only for too long buffers and log error */ if (len > MAX_BUFF) pr_err("Source string returned from BIOS is out of bound!\n"); } /** * get_wmiobj_pointer() - Get Content of WMI block for particular instance * @instance_id: WMI instance ID * @guid_string: WMI GUID (in str form) * * Fetches the content for WMI block (instance_id) under GUID (guid_string) * Caller must kfree the return */ union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string) { struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL }; acpi_status status; status = wmi_query_block(guid_string, instance_id, &out); return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL; } /** * get_instance_count() - Compute total number of instances under guid_string * @guid_string: WMI GUID (in string form) */ int get_instance_count(const char *guid_string) { union acpi_object *wmi_obj = NULL; int i = 0; do { kfree(wmi_obj); wmi_obj = get_wmiobj_pointer(i, guid_string); i++; } while (wmi_obj); return (i-1); } /** * alloc_attributes_data() - Allocate attributes data for a particular type * @attr_type: Attribute type to allocate */ static int alloc_attributes_data(int attr_type) { int retval = 0; switch (attr_type) { case ENUM: retval = alloc_enum_data(); break; case INT: retval = alloc_int_data(); break; case STR: retval = alloc_str_data(); break; case PO: retval = alloc_po_data(); break; default: break; } return retval; } /** * destroy_attribute_objs() - Free a kset of kobjects * @kset: The kset to destroy * * Fress kobjects created for each attribute_name under attribute type kset */ static void destroy_attribute_objs(struct kset *kset) { struct kobject *pos, *next; list_for_each_entry_safe(pos, next, &kset->list, entry) { kobject_put(pos); } } /** * release_attributes_data() - Clean-up all sysfs directories and files created */ static void release_attributes_data(void) { mutex_lock(&wmi_priv.mutex); exit_enum_attributes(); exit_int_attributes(); exit_str_attributes(); exit_po_attributes(); if (wmi_priv.authentication_dir_kset) { destroy_attribute_objs(wmi_priv.authentication_dir_kset); kset_unregister(wmi_priv.authentication_dir_kset); wmi_priv.authentication_dir_kset = NULL; } if (wmi_priv.main_dir_kset) { sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr); sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr); destroy_attribute_objs(wmi_priv.main_dir_kset); kset_unregister(wmi_priv.main_dir_kset); wmi_priv.main_dir_kset = NULL; } mutex_unlock(&wmi_priv.mutex); } /** * init_bios_attributes() - Initialize all attributes for a type * @attr_type: The attribute type to initialize * @guid: The WMI GUID associated with this type to initialize * * Initialiaze all 4 types of attributes enumeration, integer, string and password object. * Populates each attrbute typ's respective properties under sysfs files */ static int init_bios_attributes(int attr_type, const char *guid) { struct kobject *attr_name_kobj; //individual attribute names union acpi_object *obj = NULL; union acpi_object *elements; struct kobject *duplicate; struct kset *tmp_set; int min_elements; /* instance_id needs to be reset for each type GUID * also, instance IDs are unique within GUID but not across */ int instance_id = 0; int retval = 0; retval = alloc_attributes_data(attr_type); if (retval) return retval; switch (attr_type) { case ENUM: min_elements = 8; break; case INT: min_elements = 9; break; case STR: min_elements = 8; break; case PO: min_elements = 4; break; default: pr_err("Error: Unknown attr_type: %d\n", attr_type); return -EINVAL; } /* need to use specific instance_id and guid combination to get right data */ obj = get_wmiobj_pointer(instance_id, guid); if (!obj) return -ENODEV; mutex_lock(&wmi_priv.mutex); while (obj) { if (obj->type != ACPI_TYPE_PACKAGE) { pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type); retval = -EIO; goto err_attr_init; } if (obj->package.count < min_elements) { pr_err("Error: ACPI-package does not have enough elements: %d < %d\n", obj->package.count, min_elements); goto nextobj; } elements = obj->package.elements; /* sanity checking */ if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) { pr_debug("incorrect element type\n"); goto nextobj; } if (strlen(elements[ATTR_NAME].string.pointer) == 0) { pr_debug("empty attribute found\n"); goto nextobj; } if (attr_type == PO) tmp_set = wmi_priv.authentication_dir_kset; else tmp_set = wmi_priv.main_dir_kset; duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer); if (duplicate) { pr_debug("Duplicate attribute name found - %s\n", elements[ATTR_NAME].string.pointer); kobject_put(duplicate); goto nextobj; } /* build attribute */ attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL); if (!attr_name_kobj) { retval = -ENOMEM; goto err_attr_init; } attr_name_kobj->kset = tmp_set; retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s", elements[ATTR_NAME].string.pointer); if (retval) { kobject_put(attr_name_kobj); goto err_attr_init; } /* enumerate all of this attribute */ switch (attr_type) { case ENUM: retval = populate_enum_data(elements, instance_id, attr_name_kobj, obj->package.count); break; case INT: retval = populate_int_data(elements, instance_id, attr_name_kobj); break; case STR: retval = populate_str_data(elements, instance_id, attr_name_kobj); break; case PO: retval = populate_po_data(elements, instance_id, attr_name_kobj); break; default: break; } if (retval) { pr_debug("failed to populate %s\n", elements[ATTR_NAME].string.pointer); goto err_attr_init; } nextobj: kfree(obj); instance_id++; obj = get_wmiobj_pointer(instance_id, guid); } mutex_unlock(&wmi_priv.mutex); return 0; err_attr_init: mutex_unlock(&wmi_priv.mutex); kfree(obj); return retval; } static int __init sysman_init(void) { int ret = 0; if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) && !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) { pr_err("Unable to run on non-Dell system\n"); return -ENODEV; } ret = init_bios_attr_set_interface(); if (ret) return ret; ret = init_bios_attr_pass_interface(); if (ret) goto err_exit_bios_attr_set_interface; if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) { pr_debug("failed to find set or pass interface\n"); ret = -ENODEV; goto err_exit_bios_attr_pass_interface; } ret = fw_attributes_class_get(&fw_attr_class); if (ret) goto err_exit_bios_attr_pass_interface; wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0), NULL, "%s", DRIVER_NAME); if (IS_ERR(wmi_priv.class_dev)) { ret = PTR_ERR(wmi_priv.class_dev); goto err_unregister_class; } wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL, &wmi_priv.class_dev->kobj); if (!wmi_priv.main_dir_kset) { ret = -ENOMEM; goto err_destroy_classdev; } wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL, &wmi_priv.class_dev->kobj); if (!wmi_priv.authentication_dir_kset) { ret = -ENOMEM; goto err_release_attributes_data; } ret = create_attributes_level_sysfs_files(); if (ret) { pr_debug("could not create reset BIOS attribute\n"); goto err_release_attributes_data; } ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID); if (ret) { pr_debug("failed to populate enumeration type attributes\n"); goto err_release_attributes_data; } ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID); if (ret) { pr_debug("failed to populate integer type attributes\n"); goto err_release_attributes_data; } ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID); if (ret) { pr_debug("failed to populate string type attributes\n"); goto err_release_attributes_data; } ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID); if (ret) { pr_debug("failed to populate pass object type attributes\n"); goto err_release_attributes_data; } return 0; err_release_attributes_data: release_attributes_data(); err_destroy_classdev: device_destroy(fw_attr_class, MKDEV(0, 0)); err_unregister_class: fw_attributes_class_put(); err_exit_bios_attr_pass_interface: exit_bios_attr_pass_interface(); err_exit_bios_attr_set_interface: exit_bios_attr_set_interface(); return ret; } static void __exit sysman_exit(void) { release_attributes_data(); device_destroy(fw_attr_class, MKDEV(0, 0)); fw_attributes_class_put(); exit_bios_attr_set_interface(); exit_bios_attr_pass_interface(); } module_init(sysman_init); module_exit(sysman_exit); MODULE_AUTHOR("Mario Limonciello "); MODULE_AUTHOR("Prasanth Ksr "); MODULE_AUTHOR("Divya Bharathi "); MODULE_DESCRIPTION("Dell platform setting control interface"); MODULE_LICENSE("GPL");