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
21 struct wmi_sysman_priv wmi_priv = {
22 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
23 };
24
25 /* reset bios to defaults */
26 static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
27 static int reset_option = -1;
28 static 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 */
populate_string_buffer(char * buffer,size_t buffer_len,const char * str)37 ssize_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 */
calculate_string_buffer(const char * str)64 size_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 */
calculate_security_buffer(char * authentication)76 size_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 */
populate_security_buffer(char * buffer,char * authentication)92 void 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 */
map_wmi_error(int error_code)110 int 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 */
reset_bios_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)145 static 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 */
reset_bios_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)167 static 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 */
pending_reboot_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)195 static 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
201 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
202 static 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 */
create_attributes_level_sysfs_files(void)209 static 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
wmi_sysman_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)224 static 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
wmi_sysman_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)236 static 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
248 static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
249 .show = wmi_sysman_attr_show,
250 .store = wmi_sysman_attr_store,
251 };
252
attr_name_release(struct kobject * kobj)253 static void attr_name_release(struct kobject *kobj)
254 {
255 kfree(kobj);
256 }
257
258 static 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 */
strlcpy_attr(char * dest,char * src)268 void 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 */
get_wmiobj_pointer(int instance_id,const char * guid_string)290 union 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 */
get_instance_count(const char * guid_string)304 int 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 */
alloc_attributes_data(int attr_type)319 static 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 */
destroy_attribute_objs(struct kset * kset)349 static 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 */
release_attributes_data(void)361 static 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 */
init_bios_attributes(int attr_type,const char * guid)391 static 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
504 nextobj:
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
513 err_attr_init:
514 mutex_unlock(&wmi_priv.mutex);
515 kfree(obj);
516 return retval;
517 }
518
sysman_init(void)519 static 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
600 err_release_attributes_data:
601 release_attributes_data();
602
603 err_destroy_classdev:
604 device_destroy(fw_attr_class, MKDEV(0, 0));
605
606 err_unregister_class:
607 fw_attributes_class_put();
608
609 err_exit_bios_attr_pass_interface:
610 exit_bios_attr_pass_interface();
611
612 err_exit_bios_attr_set_interface:
613 exit_bios_attr_set_interface();
614
615 return ret;
616 }
617
sysman_exit(void)618 static 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
627 module_init(sysman_init);
628 module_exit(sysman_exit);
629
630 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
631 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
632 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
633 MODULE_DESCRIPTION("Dell platform setting control interface");
634 MODULE_LICENSE("GPL");
635
