sysman.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Common methods for use with dell-wmi-sysman
  4 *
  5 *  Copyright (c) 2020 Dell Inc.
  6 */
  7
  8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  9
 10#include <linux/fs.h>
 11#include <linux/dmi.h>
 12#include <linux/module.h>
 13#include <linux/kernel.h>
 14#include <linux/wmi.h>
 15#include "dell-wmi-sysman.h"
 16#include "../../firmware_attributes_class.h"
 17
 18#define MAX_TYPES  4
 19#include <linux/nls.h>
 20
 21struct wmi_sysman_priv wmi_priv = {
 22	.mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
 23};
 24
 25/* reset bios to defaults */
 26static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
 27static int reset_option = -1;
 28
 29
 30/**
 31 * populate_string_buffer() - populates a string buffer
 32 * @buffer: the start of the destination buffer
 33 * @buffer_len: length of the destination buffer
 34 * @str: the string to insert into buffer
 35 */
 36ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
 37{
 38	u16 *length = (u16 *)buffer;
 39	u16 *target = length + 1;
 40	int ret;
 41
 42	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
 43			      target, buffer_len - sizeof(u16));
 44	if (ret < 0) {
 45		dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
 46		return ret;
 47	}
 48
 49	if ((ret * sizeof(u16)) > U16_MAX) {
 50		dev_err(wmi_priv.class_dev, "Error string too long\n");
 51		return -ERANGE;
 52	}
 53
 54	*length = ret * sizeof(u16);
 55	return sizeof(u16) + *length;
 56}
 57
 58/**
 59 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
 60 * @str: the string to calculate based upon
 61 *
 62 */
 63size_t calculate_string_buffer(const char *str)
 64{
 65	/* u16 length field + one UTF16 char for each input char */
 66	return sizeof(u16) + strlen(str) * sizeof(u16);
 67}
 68
 69/**
 70 * calculate_security_buffer() - determines size of security buffer for authentication scheme
 71 * @authentication: the authentication content
 72 *
 73 * Currently only supported type is Admin password
 74 */
 75size_t calculate_security_buffer(char *authentication)
 76{
 77	if (strlen(authentication) > 0) {
 78		return (sizeof(u32) * 2) + strlen(authentication) +
 79			strlen(authentication) % 2;
 80	}
 81	return sizeof(u32) * 2;
 82}
 83
 84/**
 85 * populate_security_buffer() - builds a security buffer for authentication scheme
 86 * @buffer: the buffer to populate
 87 * @authentication: the authentication content
 88 *
 89 * Currently only supported type is PLAIN TEXT
 90 */
 91void populate_security_buffer(char *buffer, char *authentication)
 92{
 93	char *auth = buffer + sizeof(u32) * 2;
 94	u32 *sectype = (u32 *) buffer;
 95	u32 *seclen = sectype + 1;
 96
 97	*sectype = strlen(authentication) > 0 ? 1 : 0;
 98	*seclen = strlen(authentication);
 99
100	/* plain text */
101	if (strlen(authentication) > 0)
102		memcpy(auth, authentication, *seclen);
103}
104
105/**
106 * map_wmi_error() - map errors from WMI methods to kernel error codes
107 * @error_code: integer error code returned from Dell's firmware
108 */
109int map_wmi_error(int error_code)
110{
111	switch (error_code) {
112	case 0:
113		/* success */
114		return 0;
115	case 1:
116		/* failed */
117		return -EIO;
118	case 2:
119		/* invalid parameter */
120		return -EINVAL;
121	case 3:
122		/* access denied */
123		return -EACCES;
124	case 4:
125		/* not supported */
126		return -EOPNOTSUPP;
127	case 5:
128		/* memory error */
129		return -ENOMEM;
130	case 6:
131		/* protocol error */
132		return -EPROTO;
133	}
134	/* unspecified error */
135	return -EIO;
136}
137
138/**
139 * reset_bios_show() - sysfs implementaton for read reset_bios
140 * @kobj: Kernel object for this attribute
141 * @attr: Kernel object attribute
142 * @buf: The buffer to display to userspace
143 */
144static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
145{
146	char *start = buf;
147	int i;
148
149	for (i = 0; i < MAX_TYPES; i++) {
150		if (i == reset_option)
151			buf += sprintf(buf, "[%s] ", reset_types[i]);
152		else
153			buf += sprintf(buf, "%s ", reset_types[i]);
154	}
155	buf += sprintf(buf, "\n");
156	return buf-start;
157}
158
159/**
160 * reset_bios_store() - sysfs implementaton for write reset_bios
161 * @kobj: Kernel object for this attribute
162 * @attr: Kernel object attribute
163 * @buf: The buffer from userspace
164 * @count: the size of the buffer from userspace
165 */
166static ssize_t reset_bios_store(struct kobject *kobj,
167				struct kobj_attribute *attr, const char *buf, size_t count)
168{
169	int type = sysfs_match_string(reset_types, buf);
170	int ret;
171
172	if (type < 0)
173		return type;
174
175	ret = set_bios_defaults(type);
176	pr_debug("reset all attributes request type %d: %d\n", type, ret);
177	if (!ret) {
178		reset_option = type;
179		ret = count;
180	}
181
182	return ret;
183}
184
185/**
186 * pending_reboot_show() - sysfs implementaton for read pending_reboot
187 * @kobj: Kernel object for this attribute
188 * @attr: Kernel object attribute
189 * @buf: The buffer to display to userspace
190 *
191 * Stores default value as 0
192 * When current_value is changed this attribute is set to 1 to notify reboot may be required
193 */
194static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
195				   char *buf)
196{
197	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
198}
199
200static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
201static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
202
203
204/**
205 * create_attributes_level_sysfs_files() - Creates reset_bios and
206 * pending_reboot attributes
207 */
208static int create_attributes_level_sysfs_files(void)
209{
210	int ret;
211
212	ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
213	if (ret)
214		return ret;
215
216	ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
217	if (ret)
218		return ret;
219
220	return 0;
221}
222
223static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
224				    char *buf)
225{
226	struct kobj_attribute *kattr;
227	ssize_t ret = -EIO;
228
229	kattr = container_of(attr, struct kobj_attribute, attr);
230	if (kattr->show)
231		ret = kattr->show(kobj, kattr, buf);
232	return ret;
233}
234
235static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
236				     const char *buf, size_t count)
237{
238	struct kobj_attribute *kattr;
239	ssize_t ret = -EIO;
240
241	kattr = container_of(attr, struct kobj_attribute, attr);
242	if (kattr->store)
243		ret = kattr->store(kobj, kattr, buf, count);
244	return ret;
245}
246
247static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
248	.show	= wmi_sysman_attr_show,
249	.store	= wmi_sysman_attr_store,
250};
251
252static void attr_name_release(struct kobject *kobj)
253{
254	kfree(kobj);
255}
256
257static const struct kobj_type attr_name_ktype = {
258	.release	= attr_name_release,
259	.sysfs_ops	= &wmi_sysman_kobj_sysfs_ops,
260};
261
262/**
263 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
264 * @dest: Where to copy the string to
265 * @src: Where to copy the string from
266 */
267void strlcpy_attr(char *dest, char *src)
268{
269	size_t len = strlen(src) + 1;
270
271	if (len > 1 && len <= MAX_BUFF)
272		strscpy(dest, src, len);
273
274	/*len can be zero because any property not-applicable to attribute can
275	 * be empty so check only for too long buffers and log error
276	 */
277	if (len > MAX_BUFF)
278		pr_err("Source string returned from BIOS is out of bound!\n");
279}
280
281/**
282 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
283 * @instance_id: WMI instance ID
284 * @guid_string: WMI GUID (in str form)
285 *
286 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
287 * Caller must kfree the return
288 */
289union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
290{
291	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
292	acpi_status status;
293
294	status = wmi_query_block(guid_string, instance_id, &out);
295
296	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
297}
298
299/**
300 * get_instance_count() - Compute total number of instances under guid_string
301 * @guid_string: WMI GUID (in string form)
302 */
303int get_instance_count(const char *guid_string)
304{
305	int ret;
306
307	ret = wmi_instance_count(guid_string);
308	if (ret < 0)
309		return 0;
310
311	return ret;
312}
313
314/**
315 * alloc_attributes_data() - Allocate attributes data for a particular type
316 * @attr_type: Attribute type to allocate
317 */
318static int alloc_attributes_data(int attr_type)
319{
320	int retval = 0;
321
322	switch (attr_type) {
323	case ENUM:
324		retval = alloc_enum_data();
325		break;
326	case INT:
327		retval = alloc_int_data();
328		break;
329	case STR:
330		retval = alloc_str_data();
331		break;
332	case PO:
333		retval = alloc_po_data();
334		break;
335	default:
336		break;
337	}
338
339	return retval;
340}
341
342/**
343 * destroy_attribute_objs() - Free a kset of kobjects
344 * @kset: The kset to destroy
345 *
346 * Fress kobjects created for each attribute_name under attribute type kset
347 */
348static void destroy_attribute_objs(struct kset *kset)
349{
350	struct kobject *pos, *next;
351
352	list_for_each_entry_safe(pos, next, &kset->list, entry) {
353		kobject_put(pos);
354	}
355}
356
357/**
358 * release_attributes_data() - Clean-up all sysfs directories and files created
359 */
360static void release_attributes_data(void)
361{
362	mutex_lock(&wmi_priv.mutex);
363	exit_enum_attributes();
364	exit_int_attributes();
365	exit_str_attributes();
366	exit_po_attributes();
367	if (wmi_priv.authentication_dir_kset) {
368		destroy_attribute_objs(wmi_priv.authentication_dir_kset);
369		kset_unregister(wmi_priv.authentication_dir_kset);
370		wmi_priv.authentication_dir_kset = NULL;
371	}
372	if (wmi_priv.main_dir_kset) {
373		sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
374		sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
375		destroy_attribute_objs(wmi_priv.main_dir_kset);
376		kset_unregister(wmi_priv.main_dir_kset);
377		wmi_priv.main_dir_kset = NULL;
378	}
379	mutex_unlock(&wmi_priv.mutex);
380}
381
382/**
383 * init_bios_attributes() - Initialize all attributes for a type
384 * @attr_type: The attribute type to initialize
385 * @guid: The WMI GUID associated with this type to initialize
386 *
387 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
388 * Populates each attrbute typ's respective properties under sysfs files
389 */
390static int init_bios_attributes(int attr_type, const char *guid)
391{
392	struct kobject *attr_name_kobj; //individual attribute names
393	union acpi_object *obj = NULL;
394	union acpi_object *elements;
395	struct kobject *duplicate;
396	struct kset *tmp_set;
397	int min_elements;
398
399	/* instance_id needs to be reset for each type GUID
400	 * also, instance IDs are unique within GUID but not across
401	 */
402	int instance_id = 0;
403	int retval = 0;
404
405	retval = alloc_attributes_data(attr_type);
406	if (retval)
407		return retval;
408
409	switch (attr_type) {
410	case ENUM:	min_elements = ENUM_MIN_ELEMENTS;	break;
411	case INT:	min_elements = INT_MIN_ELEMENTS;	break;
412	case STR:	min_elements = STR_MIN_ELEMENTS;	break;
413	case PO:	min_elements = PO_MIN_ELEMENTS;		break;
414	default:
415		pr_err("Error: Unknown attr_type: %d\n", attr_type);
416		return -EINVAL;
417	}
418
419	/* need to use specific instance_id and guid combination to get right data */
420	obj = get_wmiobj_pointer(instance_id, guid);
421	if (!obj)
422		return -ENODEV;
423
424	mutex_lock(&wmi_priv.mutex);
425	while (obj) {
426		if (obj->type != ACPI_TYPE_PACKAGE) {
427			pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
428			retval = -EIO;
429			goto err_attr_init;
430		}
431
432		if (obj->package.count < min_elements) {
433			pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
434			       obj->package.count, min_elements);
435			goto nextobj;
436		}
437
438		elements = obj->package.elements;
439
440		/* sanity checking */
441		if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
442			pr_debug("incorrect element type\n");
443			goto nextobj;
444		}
445		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
446			pr_debug("empty attribute found\n");
447			goto nextobj;
448		}
449		if (attr_type == PO)
450			tmp_set = wmi_priv.authentication_dir_kset;
451		else
452			tmp_set = wmi_priv.main_dir_kset;
453
454		duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
455		if (duplicate) {
456			pr_debug("Duplicate attribute name found - %s\n",
457				 elements[ATTR_NAME].string.pointer);
458			kobject_put(duplicate);
459			goto nextobj;
460		}
461
462		/* build attribute */
463		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
464		if (!attr_name_kobj) {
465			retval = -ENOMEM;
466			goto err_attr_init;
467		}
468
469		attr_name_kobj->kset = tmp_set;
470
471		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
472						elements[ATTR_NAME].string.pointer);
473		if (retval) {
474			kobject_put(attr_name_kobj);
475			goto err_attr_init;
476		}
477
478		/* enumerate all of this attribute */
479		switch (attr_type) {
480		case ENUM:
481			retval = populate_enum_data(elements, instance_id, attr_name_kobj,
482					obj->package.count);
483			break;
484		case INT:
485			retval = populate_int_data(elements, instance_id, attr_name_kobj);
486			break;
487		case STR:
488			retval = populate_str_data(elements, instance_id, attr_name_kobj);
489			break;
490		case PO:
491			retval = populate_po_data(elements, instance_id, attr_name_kobj);
492			break;
493		default:
494			break;
495		}
496
497		if (retval) {
498			pr_debug("failed to populate %s\n",
499				elements[ATTR_NAME].string.pointer);
500			goto err_attr_init;
501		}
502
503nextobj:
504		kfree(obj);
505		instance_id++;
506		obj = get_wmiobj_pointer(instance_id, guid);
507	}
508
509	mutex_unlock(&wmi_priv.mutex);
510	return 0;
511
512err_attr_init:
513	mutex_unlock(&wmi_priv.mutex);
514	kfree(obj);
515	return retval;
516}
517
518static int __init sysman_init(void)
519{
520	int ret = 0;
521
522	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
523	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Alienware", NULL) &&
524	    !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
525		pr_err("Unable to run on non-Dell system\n");
526		return -ENODEV;
527	}
528
529	ret = init_bios_attr_set_interface();
530	if (ret)
531		return ret;
532
533	ret = init_bios_attr_pass_interface();
534	if (ret)
535		goto err_exit_bios_attr_set_interface;
536
537	if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
538		pr_debug("failed to find set or pass interface\n");
539		ret = -ENODEV;
540		goto err_exit_bios_attr_pass_interface;
541	}
542
543	wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
544				  NULL, "%s", DRIVER_NAME);
545	if (IS_ERR(wmi_priv.class_dev)) {
546		ret = PTR_ERR(wmi_priv.class_dev);
547		goto err_exit_bios_attr_pass_interface;
548	}
549
550	wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
551						     &wmi_priv.class_dev->kobj);
552	if (!wmi_priv.main_dir_kset) {
553		ret = -ENOMEM;
554		goto err_destroy_classdev;
555	}
556
557	wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
558								&wmi_priv.class_dev->kobj);
559	if (!wmi_priv.authentication_dir_kset) {
560		ret = -ENOMEM;
561		goto err_release_attributes_data;
562	}
563
564	ret = create_attributes_level_sysfs_files();
565	if (ret) {
566		pr_debug("could not create reset BIOS attribute\n");
567		goto err_release_attributes_data;
568	}
569
570	ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
571	if (ret) {
572		pr_debug("failed to populate enumeration type attributes\n");
573		goto err_release_attributes_data;
574	}
575
576	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
577	if (ret) {
578		pr_debug("failed to populate integer type attributes\n");
579		goto err_release_attributes_data;
580	}
581
582	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
583	if (ret) {
584		pr_debug("failed to populate string type attributes\n");
585		goto err_release_attributes_data;
586	}
587
588	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
589	if (ret) {
590		pr_debug("failed to populate pass object type attributes\n");
591		goto err_release_attributes_data;
592	}
593
594	return 0;
595
596err_release_attributes_data:
597	release_attributes_data();
598
599err_destroy_classdev:
600	device_unregister(wmi_priv.class_dev);
601
602err_exit_bios_attr_pass_interface:
603	exit_bios_attr_pass_interface();
604
605err_exit_bios_attr_set_interface:
606	exit_bios_attr_set_interface();
607
608	return ret;
609}
610
611static void __exit sysman_exit(void)
612{
613	release_attributes_data();
614	device_unregister(wmi_priv.class_dev);
615	exit_bios_attr_set_interface();
616	exit_bios_attr_pass_interface();
617}
618
619module_init(sysman_init);
620module_exit(sysman_exit);
621
622MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
623MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
624MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
625MODULE_DESCRIPTION("Dell platform setting control interface");
626MODULE_LICENSE("GPL");