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;
28static const struct class *fw_attr_class;
29
30
31/**
32 * populate_string_buffer() - populates a string buffer
33 * @buffer: the start of the destination buffer
34 * @buffer_len: length of the destination buffer
35 * @str: the string to insert into buffer
36 */
37ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
38{
39	u16 *length = (u16 *)buffer;
40	u16 *target = length + 1;
41	int ret;
42
43	ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
44			      target, buffer_len - sizeof(u16));
45	if (ret < 0) {
46		dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
47		return ret;
48	}
49
50	if ((ret * sizeof(u16)) > U16_MAX) {
51		dev_err(wmi_priv.class_dev, "Error string too long\n");
52		return -ERANGE;
53	}
54
55	*length = ret * sizeof(u16);
56	return sizeof(u16) + *length;
57}
58
59/**
60 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
61 * @str: the string to calculate based upon
62 *
63 */
64size_t calculate_string_buffer(const char *str)
65{
66	/* u16 length field + one UTF16 char for each input char */
67	return sizeof(u16) + strlen(str) * sizeof(u16);
68}
69
70/**
71 * calculate_security_buffer() - determines size of security buffer for authentication scheme
72 * @authentication: the authentication content
73 *
74 * Currently only supported type is Admin password
75 */
76size_t calculate_security_buffer(char *authentication)
77{
78	if (strlen(authentication) > 0) {
79		return (sizeof(u32) * 2) + strlen(authentication) +
80			strlen(authentication) % 2;
81	}
82	return sizeof(u32) * 2;
83}
84
85/**
86 * populate_security_buffer() - builds a security buffer for authentication scheme
87 * @buffer: the buffer to populate
88 * @authentication: the authentication content
89 *
90 * Currently only supported type is PLAIN TEXT
91 */
92void populate_security_buffer(char *buffer, char *authentication)
93{
94	char *auth = buffer + sizeof(u32) * 2;
95	u32 *sectype = (u32 *) buffer;
96	u32 *seclen = sectype + 1;
97
98	*sectype = strlen(authentication) > 0 ? 1 : 0;
99	*seclen = strlen(authentication);
100
101	/* plain text */
102	if (strlen(authentication) > 0)
103		memcpy(auth, authentication, *seclen);
104}
105
106/**
107 * map_wmi_error() - map errors from WMI methods to kernel error codes
108 * @error_code: integer error code returned from Dell's firmware
109 */
110int map_wmi_error(int error_code)
111{
112	switch (error_code) {
113	case 0:
114		/* success */
115		return 0;
116	case 1:
117		/* failed */
118		return -EIO;
119	case 2:
120		/* invalid parameter */
121		return -EINVAL;
122	case 3:
123		/* access denied */
124		return -EACCES;
125	case 4:
126		/* not supported */
127		return -EOPNOTSUPP;
128	case 5:
129		/* memory error */
130		return -ENOMEM;
131	case 6:
132		/* protocol error */
133		return -EPROTO;
134	}
135	/* unspecified error */
136	return -EIO;
137}
138
139/**
140 * reset_bios_show() - sysfs implementaton for read reset_bios
141 * @kobj: Kernel object for this attribute
142 * @attr: Kernel object attribute
143 * @buf: The buffer to display to userspace
144 */
145static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
146{
147	char *start = buf;
148	int i;
149
150	for (i = 0; i < MAX_TYPES; i++) {
151		if (i == reset_option)
152			buf += sprintf(buf, "[%s] ", reset_types[i]);
153		else
154			buf += sprintf(buf, "%s ", reset_types[i]);
155	}
156	buf += sprintf(buf, "\n");
157	return buf-start;
158}
159
160/**
161 * reset_bios_store() - sysfs implementaton for write reset_bios
162 * @kobj: Kernel object for this attribute
163 * @attr: Kernel object attribute
164 * @buf: The buffer from userspace
165 * @count: the size of the buffer from userspace
166 */
167static ssize_t reset_bios_store(struct kobject *kobj,
168				struct kobj_attribute *attr, const char *buf, size_t count)
169{
170	int type = sysfs_match_string(reset_types, buf);
171	int ret;
172
173	if (type < 0)
174		return type;
175
176	ret = set_bios_defaults(type);
177	pr_debug("reset all attributes request type %d: %d\n", type, ret);
178	if (!ret) {
179		reset_option = type;
180		ret = count;
181	}
182
183	return ret;
184}
185
186/**
187 * pending_reboot_show() - sysfs implementaton for read pending_reboot
188 * @kobj: Kernel object for this attribute
189 * @attr: Kernel object attribute
190 * @buf: The buffer to display to userspace
191 *
192 * Stores default value as 0
193 * When current_value is changed this attribute is set to 1 to notify reboot may be required
194 */
195static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
196				   char *buf)
197{
198	return sprintf(buf, "%d\n", wmi_priv.pending_changes);
199}
200
201static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
202static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
203
204
205/**
206 * create_attributes_level_sysfs_files() - Creates reset_bios and
207 * pending_reboot attributes
208 */
209static int create_attributes_level_sysfs_files(void)
210{
211	int ret;
212
213	ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
214	if (ret)
215		return ret;
216
217	ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
218	if (ret)
219		return ret;
220
221	return 0;
222}
223
224static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
225				    char *buf)
226{
227	struct kobj_attribute *kattr;
228	ssize_t ret = -EIO;
229
230	kattr = container_of(attr, struct kobj_attribute, attr);
231	if (kattr->show)
232		ret = kattr->show(kobj, kattr, buf);
233	return ret;
234}
235
236static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
237				     const char *buf, size_t count)
238{
239	struct kobj_attribute *kattr;
240	ssize_t ret = -EIO;
241
242	kattr = container_of(attr, struct kobj_attribute, attr);
243	if (kattr->store)
244		ret = kattr->store(kobj, kattr, buf, count);
245	return ret;
246}
247
248static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
249	.show	= wmi_sysman_attr_show,
250	.store	= wmi_sysman_attr_store,
251};
252
253static void attr_name_release(struct kobject *kobj)
254{
255	kfree(kobj);
256}
257
258static const struct kobj_type attr_name_ktype = {
259	.release	= attr_name_release,
260	.sysfs_ops	= &wmi_sysman_kobj_sysfs_ops,
261};
262
263/**
264 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
265 * @dest: Where to copy the string to
266 * @src: Where to copy the string from
267 */
268void strlcpy_attr(char *dest, char *src)
269{
270	size_t len = strlen(src) + 1;
271
272	if (len > 1 && len <= MAX_BUFF)
273		strscpy(dest, src, len);
274
275	/*len can be zero because any property not-applicable to attribute can
276	 * be empty so check only for too long buffers and log error
277	 */
278	if (len > MAX_BUFF)
279		pr_err("Source string returned from BIOS is out of bound!\n");
280}
281
282/**
283 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
284 * @instance_id: WMI instance ID
285 * @guid_string: WMI GUID (in str form)
286 *
287 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
288 * Caller must kfree the return
289 */
290union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
291{
292	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
293	acpi_status status;
294
295	status = wmi_query_block(guid_string, instance_id, &out);
296
297	return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
298}
299
300/**
301 * get_instance_count() - Compute total number of instances under guid_string
302 * @guid_string: WMI GUID (in string form)
303 */
304int get_instance_count(const char *guid_string)
305{
306	int ret;
307
308	ret = wmi_instance_count(guid_string);
309	if (ret < 0)
310		return 0;
311
312	return ret;
313}
314
315/**
316 * alloc_attributes_data() - Allocate attributes data for a particular type
317 * @attr_type: Attribute type to allocate
318 */
319static int alloc_attributes_data(int attr_type)
320{
321	int retval = 0;
322
323	switch (attr_type) {
324	case ENUM:
325		retval = alloc_enum_data();
326		break;
327	case INT:
328		retval = alloc_int_data();
329		break;
330	case STR:
331		retval = alloc_str_data();
332		break;
333	case PO:
334		retval = alloc_po_data();
335		break;
336	default:
337		break;
338	}
339
340	return retval;
341}
342
343/**
344 * destroy_attribute_objs() - Free a kset of kobjects
345 * @kset: The kset to destroy
346 *
347 * Fress kobjects created for each attribute_name under attribute type kset
348 */
349static void destroy_attribute_objs(struct kset *kset)
350{
351	struct kobject *pos, *next;
352
353	list_for_each_entry_safe(pos, next, &kset->list, entry) {
354		kobject_put(pos);
355	}
356}
357
358/**
359 * release_attributes_data() - Clean-up all sysfs directories and files created
360 */
361static void release_attributes_data(void)
362{
363	mutex_lock(&wmi_priv.mutex);
364	exit_enum_attributes();
365	exit_int_attributes();
366	exit_str_attributes();
367	exit_po_attributes();
368	if (wmi_priv.authentication_dir_kset) {
369		destroy_attribute_objs(wmi_priv.authentication_dir_kset);
370		kset_unregister(wmi_priv.authentication_dir_kset);
371		wmi_priv.authentication_dir_kset = NULL;
372	}
373	if (wmi_priv.main_dir_kset) {
374		sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
375		sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
376		destroy_attribute_objs(wmi_priv.main_dir_kset);
377		kset_unregister(wmi_priv.main_dir_kset);
378		wmi_priv.main_dir_kset = NULL;
379	}
380	mutex_unlock(&wmi_priv.mutex);
381}
382
383/**
384 * init_bios_attributes() - Initialize all attributes for a type
385 * @attr_type: The attribute type to initialize
386 * @guid: The WMI GUID associated with this type to initialize
387 *
388 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
389 * Populates each attrbute typ's respective properties under sysfs files
390 */
391static int init_bios_attributes(int attr_type, const char *guid)
392{
393	struct kobject *attr_name_kobj; //individual attribute names
394	union acpi_object *obj = NULL;
395	union acpi_object *elements;
396	struct kobject *duplicate;
397	struct kset *tmp_set;
398	int min_elements;
399
400	/* instance_id needs to be reset for each type GUID
401	 * also, instance IDs are unique within GUID but not across
402	 */
403	int instance_id = 0;
404	int retval = 0;
405
406	retval = alloc_attributes_data(attr_type);
407	if (retval)
408		return retval;
409
410	switch (attr_type) {
411	case ENUM:	min_elements = 8;	break;
412	case INT:	min_elements = 9;	break;
413	case STR:	min_elements = 8;	break;
414	case PO:	min_elements = 4;	break;
415	default:
416		pr_err("Error: Unknown attr_type: %d\n", attr_type);
417		return -EINVAL;
418	}
419
420	/* need to use specific instance_id and guid combination to get right data */
421	obj = get_wmiobj_pointer(instance_id, guid);
422	if (!obj)
423		return -ENODEV;
424
425	mutex_lock(&wmi_priv.mutex);
426	while (obj) {
427		if (obj->type != ACPI_TYPE_PACKAGE) {
428			pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
429			retval = -EIO;
430			goto err_attr_init;
431		}
432
433		if (obj->package.count < min_elements) {
434			pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
435			       obj->package.count, min_elements);
436			goto nextobj;
437		}
438
439		elements = obj->package.elements;
440
441		/* sanity checking */
442		if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
443			pr_debug("incorrect element type\n");
444			goto nextobj;
445		}
446		if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
447			pr_debug("empty attribute found\n");
448			goto nextobj;
449		}
450		if (attr_type == PO)
451			tmp_set = wmi_priv.authentication_dir_kset;
452		else
453			tmp_set = wmi_priv.main_dir_kset;
454
455		duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
456		if (duplicate) {
457			pr_debug("Duplicate attribute name found - %s\n",
458				 elements[ATTR_NAME].string.pointer);
459			kobject_put(duplicate);
460			goto nextobj;
461		}
462
463		/* build attribute */
464		attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
465		if (!attr_name_kobj) {
466			retval = -ENOMEM;
467			goto err_attr_init;
468		}
469
470		attr_name_kobj->kset = tmp_set;
471
472		retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
473						elements[ATTR_NAME].string.pointer);
474		if (retval) {
475			kobject_put(attr_name_kobj);
476			goto err_attr_init;
477		}
478
479		/* enumerate all of this attribute */
480		switch (attr_type) {
481		case ENUM:
482			retval = populate_enum_data(elements, instance_id, attr_name_kobj,
483					obj->package.count);
484			break;
485		case INT:
486			retval = populate_int_data(elements, instance_id, attr_name_kobj);
487			break;
488		case STR:
489			retval = populate_str_data(elements, instance_id, attr_name_kobj);
490			break;
491		case PO:
492			retval = populate_po_data(elements, instance_id, attr_name_kobj);
493			break;
494		default:
495			break;
496		}
497
498		if (retval) {
499			pr_debug("failed to populate %s\n",
500				elements[ATTR_NAME].string.pointer);
501			goto err_attr_init;
502		}
503
504nextobj:
505		kfree(obj);
506		instance_id++;
507		obj = get_wmiobj_pointer(instance_id, guid);
508	}
509
510	mutex_unlock(&wmi_priv.mutex);
511	return 0;
512
513err_attr_init:
514	mutex_unlock(&wmi_priv.mutex);
515	kfree(obj);
516	return retval;
517}
518
519static int __init sysman_init(void)
520{
521	int ret = 0;
522
523	if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", 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	ret = fw_attributes_class_get(&fw_attr_class);
544	if (ret)
545		goto err_exit_bios_attr_pass_interface;
546
547	wmi_priv.class_dev = device_create(fw_attr_class, NULL, MKDEV(0, 0),
548				  NULL, "%s", DRIVER_NAME);
549	if (IS_ERR(wmi_priv.class_dev)) {
550		ret = PTR_ERR(wmi_priv.class_dev);
551		goto err_unregister_class;
552	}
553
554	wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
555						     &wmi_priv.class_dev->kobj);
556	if (!wmi_priv.main_dir_kset) {
557		ret = -ENOMEM;
558		goto err_destroy_classdev;
559	}
560
561	wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
562								&wmi_priv.class_dev->kobj);
563	if (!wmi_priv.authentication_dir_kset) {
564		ret = -ENOMEM;
565		goto err_release_attributes_data;
566	}
567
568	ret = create_attributes_level_sysfs_files();
569	if (ret) {
570		pr_debug("could not create reset BIOS attribute\n");
571		goto err_release_attributes_data;
572	}
573
574	ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
575	if (ret) {
576		pr_debug("failed to populate enumeration type attributes\n");
577		goto err_release_attributes_data;
578	}
579
580	ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
581	if (ret) {
582		pr_debug("failed to populate integer type attributes\n");
583		goto err_release_attributes_data;
584	}
585
586	ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
587	if (ret) {
588		pr_debug("failed to populate string type attributes\n");
589		goto err_release_attributes_data;
590	}
591
592	ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
593	if (ret) {
594		pr_debug("failed to populate pass object type attributes\n");
595		goto err_release_attributes_data;
596	}
597
598	return 0;
599
600err_release_attributes_data:
601	release_attributes_data();
602
603err_destroy_classdev:
604	device_destroy(fw_attr_class, MKDEV(0, 0));
605
606err_unregister_class:
607	fw_attributes_class_put();
608
609err_exit_bios_attr_pass_interface:
610	exit_bios_attr_pass_interface();
611
612err_exit_bios_attr_set_interface:
613	exit_bios_attr_set_interface();
614
615	return ret;
616}
617
618static void __exit sysman_exit(void)
619{
620	release_attributes_data();
621	device_destroy(fw_attr_class, MKDEV(0, 0));
622	fw_attributes_class_put();
623	exit_bios_attr_set_interface();
624	exit_bios_attr_pass_interface();
625}
626
627module_init(sysman_init);
628module_exit(sysman_exit);
629
630MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
631MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
632MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
633MODULE_DESCRIPTION("Dell platform setting control interface");
634MODULE_LICENSE("GPL");
635