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
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 */
populate_string_buffer(char * buffer,size_t buffer_len,const char * str)36 ssize_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 */
calculate_string_buffer(const char * str)63 size_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 */
calculate_security_buffer(char * authentication)75 size_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 */
populate_security_buffer(char * buffer,char * authentication)91 void 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 */
map_wmi_error(int error_code)109 int 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 */
reset_bios_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)144 static 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 */
reset_bios_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)166 static 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 */
pending_reboot_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)194 static 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
200 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
201 static 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 */
create_attributes_level_sysfs_files(void)208 static 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
wmi_sysman_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)223 static 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
wmi_sysman_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)235 static 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
247 static const struct sysfs_ops wmi_sysman_kobj_sysfs_ops = {
248 .show = wmi_sysman_attr_show,
249 .store = wmi_sysman_attr_store,
250 };
251
attr_name_release(struct kobject * kobj)252 static void attr_name_release(struct kobject *kobj)
253 {
254 kfree(kobj);
255 }
256
257 static 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 */
strlcpy_attr(char * dest,char * src)267 void 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 */
get_wmiobj_pointer(int instance_id,const char * guid_string)289 union 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 */
get_instance_count(const char * guid_string)303 int 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 */
alloc_attributes_data(int attr_type)318 static 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 */
destroy_attribute_objs(struct kset * kset)348 static 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 */
release_attributes_data(void)360 static 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 */
init_bios_attributes(int attr_type,const char * guid)390 static 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 = 8; break;
411 case INT: min_elements = 9; break;
412 case STR: min_elements = 8; break;
413 case PO: min_elements = 4; 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
503 nextobj:
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
512 err_attr_init:
513 mutex_unlock(&wmi_priv.mutex);
514 kfree(obj);
515 return retval;
516 }
517
sysman_init(void)518 static 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
596 err_release_attributes_data:
597 release_attributes_data();
598
599 err_destroy_classdev:
600 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
601
602 err_exit_bios_attr_pass_interface:
603 exit_bios_attr_pass_interface();
604
605 err_exit_bios_attr_set_interface:
606 exit_bios_attr_set_interface();
607
608 return ret;
609 }
610
sysman_exit(void)611 static void __exit sysman_exit(void)
612 {
613 release_attributes_data();
614 device_destroy(&firmware_attributes_class, MKDEV(0, 0));
615 exit_bios_attr_set_interface();
616 exit_bios_attr_pass_interface();
617 }
618
619 module_init(sysman_init);
620 module_exit(sysman_exit);
621
622 MODULE_AUTHOR("Mario Limonciello <[email protected]>");
623 MODULE_AUTHOR("Prasanth Ksr <[email protected]>");
624 MODULE_AUTHOR("Divya Bharathi <[email protected]>");
625 MODULE_DESCRIPTION("Dell platform setting control interface");
626 MODULE_LICENSE("GPL");
627