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
17 #define MAX_TYPES 4
18 #include <linux/nls.h>
19
20 static struct class firmware_attributes_class = {
21 .name = "firmware-attributes",
22 };
23
24 struct wmi_sysman_priv wmi_priv = {
25 .mutex = __MUTEX_INITIALIZER(wmi_priv.mutex),
26 };
27
28 /* reset bios to defaults */
29 static const char * const reset_types[] = {"builtinsafe", "lastknowngood", "factory", "custom"};
30 static int reset_option = -1;
31
32
33 /**
34 * populate_string_buffer() - populates a string buffer
35 * @buffer: the start of the destination buffer
36 * @buffer_len: length of the destination buffer
37 * @str: the string to insert into buffer
38 */
populate_string_buffer(char * buffer,size_t buffer_len,const char * str)39 ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str)
40 {
41 u16 *length = (u16 *)buffer;
42 u16 *target = length + 1;
43 int ret;
44
45 ret = utf8s_to_utf16s(str, strlen(str), UTF16_HOST_ENDIAN,
46 target, buffer_len - sizeof(u16));
47 if (ret < 0) {
48 dev_err(wmi_priv.class_dev, "UTF16 conversion failed\n");
49 return ret;
50 }
51
52 if ((ret * sizeof(u16)) > U16_MAX) {
53 dev_err(wmi_priv.class_dev, "Error string too long\n");
54 return -ERANGE;
55 }
56
57 *length = ret * sizeof(u16);
58 return sizeof(u16) + *length;
59 }
60
61 /**
62 * calculate_string_buffer() - determines size of string buffer for use with BIOS communication
63 * @str: the string to calculate based upon
64 *
65 */
calculate_string_buffer(const char * str)66 size_t calculate_string_buffer(const char *str)
67 {
68 /* u16 length field + one UTF16 char for each input char */
69 return sizeof(u16) + strlen(str) * sizeof(u16);
70 }
71
72 /**
73 * calculate_security_buffer() - determines size of security buffer for authentication scheme
74 * @authentication: the authentication content
75 *
76 * Currently only supported type is Admin password
77 */
calculate_security_buffer(char * authentication)78 size_t calculate_security_buffer(char *authentication)
79 {
80 if (strlen(authentication) > 0) {
81 return (sizeof(u32) * 2) + strlen(authentication) +
82 strlen(authentication) % 2;
83 }
84 return sizeof(u32) * 2;
85 }
86
87 /**
88 * populate_security_buffer() - builds a security buffer for authentication scheme
89 * @buffer: the buffer to populate
90 * @authentication: the authentication content
91 *
92 * Currently only supported type is PLAIN TEXT
93 */
populate_security_buffer(char * buffer,char * authentication)94 void populate_security_buffer(char *buffer, char *authentication)
95 {
96 char *auth = buffer + sizeof(u32) * 2;
97 u32 *sectype = (u32 *) buffer;
98 u32 *seclen = sectype + 1;
99
100 *sectype = strlen(authentication) > 0 ? 1 : 0;
101 *seclen = strlen(authentication);
102
103 /* plain text */
104 if (strlen(authentication) > 0)
105 memcpy(auth, authentication, *seclen);
106 }
107
108 /**
109 * map_wmi_error() - map errors from WMI methods to kernel error codes
110 * @error_code: integer error code returned from Dell's firmware
111 */
map_wmi_error(int error_code)112 int map_wmi_error(int error_code)
113 {
114 switch (error_code) {
115 case 0:
116 /* success */
117 return 0;
118 case 1:
119 /* failed */
120 return -EIO;
121 case 2:
122 /* invalid parameter */
123 return -EINVAL;
124 case 3:
125 /* access denied */
126 return -EACCES;
127 case 4:
128 /* not supported */
129 return -EOPNOTSUPP;
130 case 5:
131 /* memory error */
132 return -ENOMEM;
133 case 6:
134 /* protocol error */
135 return -EPROTO;
136 }
137 /* unspecified error */
138 return -EIO;
139 }
140
141 /**
142 * reset_bios_show() - sysfs implementaton for read reset_bios
143 * @kobj: Kernel object for this attribute
144 * @attr: Kernel object attribute
145 * @buf: The buffer to display to userspace
146 */
reset_bios_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)147 static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
148 {
149 char *start = buf;
150 int i;
151
152 for (i = 0; i < MAX_TYPES; i++) {
153 if (i == reset_option)
154 buf += sprintf(buf, "[%s] ", reset_types[i]);
155 else
156 buf += sprintf(buf, "%s ", reset_types[i]);
157 }
158 buf += sprintf(buf, "\n");
159 return buf-start;
160 }
161
162 /**
163 * reset_bios_store() - sysfs implementaton for write reset_bios
164 * @kobj: Kernel object for this attribute
165 * @attr: Kernel object attribute
166 * @buf: The buffer from userspace
167 * @count: the size of the buffer from userspace
168 */
reset_bios_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)169 static ssize_t reset_bios_store(struct kobject *kobj,
170 struct kobj_attribute *attr, const char *buf, size_t count)
171 {
172 int type = sysfs_match_string(reset_types, buf);
173 int ret;
174
175 if (type < 0)
176 return type;
177
178 ret = set_bios_defaults(type);
179 pr_debug("reset all attributes request type %d: %d\n", type, ret);
180 if (!ret) {
181 reset_option = type;
182 ret = count;
183 }
184
185 return ret;
186 }
187
188 /**
189 * pending_reboot_show() - sysfs implementaton for read pending_reboot
190 * @kobj: Kernel object for this attribute
191 * @attr: Kernel object attribute
192 * @buf: The buffer to display to userspace
193 *
194 * Stores default value as 0
195 * When current_value is changed this attribute is set to 1 to notify reboot may be required
196 */
pending_reboot_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)197 static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
198 char *buf)
199 {
200 return sprintf(buf, "%d\n", wmi_priv.pending_changes);
201 }
202
203 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
204 static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
205
206
207 /**
208 * create_attributes_level_sysfs_files() - Creates reset_bios and
209 * pending_reboot attributes
210 */
create_attributes_level_sysfs_files(void)211 static int create_attributes_level_sysfs_files(void)
212 {
213 int ret;
214
215 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
216 if (ret)
217 return ret;
218
219 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
220 if (ret)
221 return ret;
222
223 return 0;
224 }
225
wmi_sysman_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)226 static ssize_t wmi_sysman_attr_show(struct kobject *kobj, struct attribute *attr,
227 char *buf)
228 {
229 struct kobj_attribute *kattr;
230 ssize_t ret = -EIO;
231
232 kattr = container_of(attr, struct kobj_attribute, attr);
233 if (kattr->show)
234 ret = kattr->show(kobj, kattr, buf);
235 return ret;
236 }
237
wmi_sysman_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)238 static ssize_t wmi_sysman_attr_store(struct kobject *kobj, struct attribute *attr,
239 const char *buf, size_t count)
240 {
241 struct kobj_attribute *kattr;
242 ssize_t ret = -EIO;
243
244 kattr = container_of(attr, struct kobj_attribute, attr);
245 if (kattr->store)
246 ret = kattr->store(kobj, kattr, buf, count);
247 return ret;
248 }
249
250 static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
251 .show = wmi_sysman_attr_show,
252 .store = wmi_sysman_attr_store,
253 };
254
attr_name_release(struct kobject * kobj)255 static void attr_name_release(struct kobject *kobj)
256 {
257 kfree(kobj);
258 }
259
260 static struct kobj_type attr_name_ktype = {
261 .release = attr_name_release,
262 .sysfs_ops = &wmi_sysman_kobj_sysfs_ops,
263 };
264
265 /**
266 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
267 * @dest: Where to copy the string to
268 * @src: Where to copy the string from
269 */
strlcpy_attr(char * dest,char * src)270 void strlcpy_attr(char *dest, char *src)
271 {
272 size_t len = strlen(src) + 1;
273
274 if (len > 1 && len <= MAX_BUFF)
275 strlcpy(dest, src, len);
276
277 /*len can be zero because any property not-applicable to attribute can
278 * be empty so check only for too long buffers and log error
279 */
280 if (len > MAX_BUFF)
281 pr_err("Source string returned from BIOS is out of bound!\n");
282 }
283
284 /**
285 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
286 * @instance_id: WMI instance ID
287 * @guid_string: WMI GUID (in str form)
288 *
289 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
290 * Caller must kfree the return
291 */
get_wmiobj_pointer(int instance_id,const char * guid_string)292 union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
293 {
294 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
295 acpi_status status;
296
297 status = wmi_query_block(guid_string, instance_id, &out);
298
299 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
300 }
301
302 /**
303 * get_instance_count() - Compute total number of instances under guid_string
304 * @guid_string: WMI GUID (in string form)
305 */
get_instance_count(const char * guid_string)306 int get_instance_count(const char *guid_string)
307 {
308 union acpi_object *wmi_obj = NULL;
309 int i = 0;
310
311 do {
312 kfree(wmi_obj);
313 wmi_obj = get_wmiobj_pointer(i, guid_string);
314 i++;
315 } while (wmi_obj);
316
317 return (i-1);
318 }
319
320 /**
321 * alloc_attributes_data() - Allocate attributes data for a particular type
322 * @attr_type: Attribute type to allocate
323 */
alloc_attributes_data(int attr_type)324 static int alloc_attributes_data(int attr_type)
325 {
326 int retval = 0;
327
328 switch (attr_type) {
329 case ENUM:
330 retval = alloc_enum_data();
331 break;
332 case INT:
333 retval = alloc_int_data();
334 break;
335 case STR:
336 retval = alloc_str_data();
337 break;
338 case PO:
339 retval = alloc_po_data();
340 break;
341 default:
342 break;
343 }
344
345 return retval;
346 }
347
348 /**
349 * destroy_attribute_objs() - Free a kset of kobjects
350 * @kset: The kset to destroy
351 *
352 * Fress kobjects created for each attribute_name under attribute type kset
353 */
destroy_attribute_objs(struct kset * kset)354 static void destroy_attribute_objs(struct kset *kset)
355 {
356 struct kobject *pos, *next;
357
358 list_for_each_entry_safe(pos, next, &kset->list, entry) {
359 kobject_put(pos);
360 }
361 }
362
363 /**
364 * release_attributes_data() - Clean-up all sysfs directories and files created
365 */
release_attributes_data(void)366 static void release_attributes_data(void)
367 {
368 mutex_lock(&wmi_priv.mutex);
369 exit_enum_attributes();
370 exit_int_attributes();
371 exit_str_attributes();
372 exit_po_attributes();
373 if (wmi_priv.authentication_dir_kset) {
374 destroy_attribute_objs(wmi_priv.authentication_dir_kset);
375 kset_unregister(wmi_priv.authentication_dir_kset);
376 wmi_priv.authentication_dir_kset = NULL;
377 }
378 if (wmi_priv.main_dir_kset) {
379 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
380 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
381 destroy_attribute_objs(wmi_priv.main_dir_kset);
382 kset_unregister(wmi_priv.main_dir_kset);
383 wmi_priv.main_dir_kset = NULL;
384 }
385 mutex_unlock(&wmi_priv.mutex);
386 }
387
388 /**
389 * init_bios_attributes() - Initialize all attributes for a type
390 * @attr_type: The attribute type to initialize
391 * @guid: The WMI GUID associated with this type to initialize
392 *
393 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
394 * Populates each attrbute typ's respective properties under sysfs files
395 */
init_bios_attributes(int attr_type,const char * guid)396 static int init_bios_attributes(int attr_type, const char *guid)
397 {
398 struct kobject *attr_name_kobj; //individual attribute names
399 union acpi_object *obj = NULL;
400 union acpi_object *elements;
401 struct kset *tmp_set;
402 int min_elements;
403
404 /* instance_id needs to be reset for each type GUID
405 * also, instance IDs are unique within GUID but not across
406 */
407 int instance_id = 0;
408 int retval = 0;
409
410 retval = alloc_attributes_data(attr_type);
411 if (retval)
412 return retval;
413
414 switch (attr_type) {
415 case ENUM: min_elements = 8; break;
416 case INT: min_elements = 9; break;
417 case STR: min_elements = 8; break;
418 case PO: min_elements = 4; break;
419 default:
420 pr_err("Error: Unknown attr_type: %d\n", attr_type);
421 return -EINVAL;
422 }
423
424 /* need to use specific instance_id and guid combination to get right data */
425 obj = get_wmiobj_pointer(instance_id, guid);
426 if (!obj)
427 return -ENODEV;
428
429 mutex_lock(&wmi_priv.mutex);
430 while (obj) {
431 if (obj->type != ACPI_TYPE_PACKAGE) {
432 pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
433 retval = -EIO;
434 goto err_attr_init;
435 }
436
437 if (obj->package.count < min_elements) {
438 pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
439 obj->package.count, min_elements);
440 goto nextobj;
441 }
442
443 elements = obj->package.elements;
444
445 /* sanity checking */
446 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
447 pr_debug("incorrect element type\n");
448 goto nextobj;
449 }
450 if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
451 pr_debug("empty attribute found\n");
452 goto nextobj;
453 }
454 if (attr_type == PO)
455 tmp_set = wmi_priv.authentication_dir_kset;
456 else
457 tmp_set = wmi_priv.main_dir_kset;
458
459 if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
460 pr_debug("duplicate attribute name found - %s\n",
461 elements[ATTR_NAME].string.pointer);
462 goto nextobj;
463 }
464
465 /* build attribute */
466 attr_name_kobj = kzalloc(sizeof(*attr_name_kobj), GFP_KERNEL);
467 if (!attr_name_kobj) {
468 retval = -ENOMEM;
469 goto err_attr_init;
470 }
471
472 attr_name_kobj->kset = tmp_set;
473
474 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
475 elements[ATTR_NAME].string.pointer);
476 if (retval) {
477 kobject_put(attr_name_kobj);
478 goto err_attr_init;
479 }
480
481 /* enumerate all of this attribute */
482 switch (attr_type) {
483 case ENUM:
484 retval = populate_enum_data(elements, instance_id, attr_name_kobj);
485 break;
486 case INT:
487 retval = populate_int_data(elements, instance_id, attr_name_kobj);
488 break;
489 case STR:
490 retval = populate_str_data(elements, instance_id, attr_name_kobj);
491 break;
492 case PO:
493 retval = populate_po_data(elements, instance_id, attr_name_kobj);
494 break;
495 default:
496 break;
497 }
498
499 if (retval) {
500 pr_debug("failed to populate %s\n",
501 elements[ATTR_NAME].string.pointer);
502 goto err_attr_init;
503 }
504
505 nextobj:
506 kfree(obj);
507 instance_id++;
508 obj = get_wmiobj_pointer(instance_id, guid);
509 }
510
511 mutex_unlock(&wmi_priv.mutex);
512 return 0;
513
514 err_attr_init:
515 mutex_unlock(&wmi_priv.mutex);
516 kfree(obj);
517 return retval;
518 }
519
sysman_init(void)520 static int __init sysman_init(void)
521 {
522 int ret = 0;
523
524 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
525 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
526 pr_err("Unable to run on non-Dell system\n");
527 return -ENODEV;
528 }
529
530 ret = init_bios_attr_set_interface();
531 if (ret)
532 return ret;
533
534 ret = init_bios_attr_pass_interface();
535 if (ret)
536 goto err_exit_bios_attr_set_interface;
537
538 if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
539 pr_debug("failed to find set or pass interface\n");
540 ret = -ENODEV;
541 goto err_exit_bios_attr_pass_interface;
542 }
543
544 ret = class_register(&firmware_attributes_class);
545 if (ret)
546 goto err_exit_bios_attr_pass_interface;
547
548 wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
549 NULL, "%s", DRIVER_NAME);
550 if (IS_ERR(wmi_priv.class_dev)) {
551 ret = PTR_ERR(wmi_priv.class_dev);
552 goto err_unregister_class;
553 }
554
555 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
556 &wmi_priv.class_dev->kobj);
557 if (!wmi_priv.main_dir_kset) {
558 ret = -ENOMEM;
559 goto err_destroy_classdev;
560 }
561
562 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
563 &wmi_priv.class_dev->kobj);
564 if (!wmi_priv.authentication_dir_kset) {
565 ret = -ENOMEM;
566 goto err_release_attributes_data;
567 }
568
569 ret = create_attributes_level_sysfs_files();
570 if (ret) {
571 pr_debug("could not create reset BIOS attribute\n");
572 goto err_release_attributes_data;
573 }
574
575 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
576 if (ret) {
577 pr_debug("failed to populate enumeration type attributes\n");
578 goto err_release_attributes_data;
579 }
580
581 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
582 if (ret) {
583 pr_debug("failed to populate integer type attributes\n");
584 goto err_release_attributes_data;
585 }
586
587 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
588 if (ret) {
589 pr_debug("failed to populate string type attributes\n");
590 goto err_release_attributes_data;
591 }
592
593 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
594 if (ret) {
595 pr_debug("failed to populate pass object type attributes\n");
596 goto err_release_attributes_data;
597 }
598
599 return 0;
600
601 err_release_attributes_data:
602 release_attributes_data();
603
604 err_destroy_classdev:
605 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
606
607 err_unregister_class:
608 class_unregister(&firmware_attributes_class);
609
610 err_exit_bios_attr_pass_interface:
611 exit_bios_attr_pass_interface();
612
613 err_exit_bios_attr_set_interface:
614 exit_bios_attr_set_interface();
615
616 return ret;
617 }
618
sysman_exit(void)619 static void __exit sysman_exit(void)
620 {
621 release_attributes_data();
622 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
623 class_unregister(&firmware_attributes_class);
624 exit_bios_attr_set_interface();
625 exit_bios_attr_pass_interface();
626 }
627
628 module_init(sysman_init);
629 module_exit(sysman_exit);
630
631 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
632 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
633 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
634 MODULE_DESCRIPTION("Dell platform setting control interface");
635 MODULE_LICENSE("GPL");
636