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/align.h>
11 #include <linux/fs.h>
12 #include <linux/dmi.h>
13 #include <linux/firmware_attributes.h>
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/sysfs.h>
18 #include <linux/wmi.h>
19 #include "dell-wmi-sysman.h"
20
21 #define MAX_TYPES 4
22 #include <linux/nls.h>
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(u8 * buffer,size_t buffer_len,const char * str)39 ssize_t populate_string_buffer(u8 *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(const char * authentication)78 size_t calculate_security_buffer(const char *authentication)
79 {
80 return sizeof(u32) * 2 + ALIGN(strlen(authentication), 2);
81 }
82
83 /**
84 * populate_security_buffer() - builds a security buffer for authentication scheme
85 * @buffer: the buffer to populate
86 * @authentication: the authentication content
87 *
88 * Currently only supported type is PLAIN TEXT
89 */
populate_security_buffer(u8 * buffer,const char * authentication)90 void populate_security_buffer(u8 *buffer, const char *authentication)
91 {
92 size_t seclen = strlen(authentication);
93 u8 *auth = buffer + sizeof(u32) * 2;
94 u32 *sectype = (u32 *) buffer;
95 u32 *seclenp = sectype + 1;
96
97 *sectype = !!seclen;
98 *seclenp = seclen;
99
100 /* plain text */
101 memcpy(auth, authentication, seclen);
102 }
103
104 /**
105 * map_wmi_error() - map errors from WMI methods to kernel error codes
106 * @error_code: integer error code returned from Dell's firmware
107 */
map_wmi_error(int error_code)108 int map_wmi_error(int error_code)
109 {
110 switch (error_code) {
111 case 0:
112 /* success */
113 return 0;
114 case 1:
115 /* failed */
116 return -EIO;
117 case 2:
118 /* invalid parameter */
119 return -EINVAL;
120 case 3:
121 /* access denied */
122 return -EACCES;
123 case 4:
124 /* not supported */
125 return -EOPNOTSUPP;
126 case 5:
127 /* memory error */
128 return -ENOMEM;
129 case 6:
130 /* protocol error */
131 return -EPROTO;
132 }
133 /* unspecified error */
134 return -EIO;
135 }
136
137 /**
138 * reset_bios_show() - sysfs implementaton for read reset_bios
139 * @kobj: Kernel object for this attribute
140 * @attr: Kernel object attribute
141 * @buf: The buffer to display to userspace
142 */
reset_bios_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)143 static ssize_t reset_bios_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
144 {
145 ssize_t len = 0;
146 int i;
147
148 for (i = 0; i < MAX_TYPES; i++) {
149 if (i == reset_option)
150 len += sysfs_emit_at(buf, len, "[%s] ", reset_types[i]);
151 else
152 len += sysfs_emit_at(buf, len, "%s ", reset_types[i]);
153 }
154 len += sysfs_emit_at(buf, len, "\n");
155 return len;
156 }
157
158 /**
159 * reset_bios_store() - sysfs implementaton for write reset_bios
160 * @kobj: Kernel object for this attribute
161 * @attr: Kernel object attribute
162 * @buf: The buffer from userspace
163 * @count: the size of the buffer from userspace
164 */
reset_bios_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)165 static ssize_t reset_bios_store(struct kobject *kobj,
166 struct kobj_attribute *attr, const char *buf, size_t count)
167 {
168 int type = sysfs_match_string(reset_types, buf);
169 int ret;
170
171 if (type < 0)
172 return type;
173
174 ret = set_bios_defaults(type);
175 pr_debug("reset all attributes request type %d: %d\n", type, ret);
176 if (!ret) {
177 reset_option = type;
178 ret = count;
179 }
180
181 return ret;
182 }
183
184 /**
185 * pending_reboot_show() - sysfs implementaton for read pending_reboot
186 * @kobj: Kernel object for this attribute
187 * @attr: Kernel object attribute
188 * @buf: The buffer to display to userspace
189 *
190 * Stores default value as 0
191 * When current_value is changed this attribute is set to 1 to notify reboot may be required
192 */
pending_reboot_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)193 static ssize_t pending_reboot_show(struct kobject *kobj, struct kobj_attribute *attr,
194 char *buf)
195 {
196 return sysfs_emit(buf, "%d\n", wmi_priv.pending_changes);
197 }
198
199 static struct kobj_attribute reset_bios = __ATTR_RW(reset_bios);
200 static struct kobj_attribute pending_reboot = __ATTR_RO(pending_reboot);
201
202
203 /**
204 * create_attributes_level_sysfs_files() - Creates reset_bios and
205 * pending_reboot attributes
206 */
create_attributes_level_sysfs_files(void)207 static int create_attributes_level_sysfs_files(void)
208 {
209 int ret;
210
211 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
212 if (ret)
213 return ret;
214
215 ret = sysfs_create_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
216 if (ret)
217 return ret;
218
219 return 0;
220 }
221
attr_name_release(struct kobject * kobj)222 static void attr_name_release(struct kobject *kobj)
223 {
224 kfree(kobj);
225 }
226
227 static const struct kobj_type attr_name_ktype = {
228 .release = attr_name_release,
229 .sysfs_ops = &kobj_sysfs_ops,
230 };
231
232 /**
233 * strlcpy_attr - Copy a length-limited, NULL-terminated string with bound checks
234 * @dest: Where to copy the string to
235 * @src: Where to copy the string from
236 */
strlcpy_attr(char * dest,char * src)237 void strlcpy_attr(char *dest, char *src)
238 {
239 size_t len = strlen(src) + 1;
240
241 if (len > 1 && len <= MAX_BUFF)
242 strscpy(dest, src, len);
243
244 /*len can be zero because any property not-applicable to attribute can
245 * be empty so check only for too long buffers and log error
246 */
247 if (len > MAX_BUFF)
248 pr_err("Source string returned from BIOS is out of bound!\n");
249 }
250
251 /**
252 * get_wmiobj_pointer() - Get Content of WMI block for particular instance
253 * @instance_id: WMI instance ID
254 * @guid_string: WMI GUID (in str form)
255 *
256 * Fetches the content for WMI block (instance_id) under GUID (guid_string)
257 * Caller must kfree the return
258 */
get_wmiobj_pointer(int instance_id,const char * guid_string)259 union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
260 {
261 struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
262 acpi_status status;
263
264 status = wmi_query_block(guid_string, instance_id, &out);
265
266 return ACPI_SUCCESS(status) ? (union acpi_object *)out.pointer : NULL;
267 }
268
269 /**
270 * get_instance_count() - Compute total number of instances under guid_string
271 * @guid_string: WMI GUID (in string form)
272 */
get_instance_count(const char * guid_string)273 int get_instance_count(const char *guid_string)
274 {
275 int ret;
276
277 ret = wmi_instance_count(guid_string);
278 if (ret < 0)
279 return 0;
280
281 return ret;
282 }
283
284 /**
285 * alloc_attributes_data() - Allocate attributes data for a particular type
286 * @attr_type: Attribute type to allocate
287 */
alloc_attributes_data(int attr_type)288 static int alloc_attributes_data(int attr_type)
289 {
290 int retval = 0;
291
292 switch (attr_type) {
293 case ENUM:
294 retval = alloc_enum_data();
295 break;
296 case INT:
297 retval = alloc_int_data();
298 break;
299 case STR:
300 retval = alloc_str_data();
301 break;
302 case PO:
303 retval = alloc_po_data();
304 break;
305 default:
306 break;
307 }
308
309 return retval;
310 }
311
312 /**
313 * destroy_attribute_objs() - Free a kset of kobjects
314 * @kset: The kset to destroy
315 *
316 * Frees kobjects created for each attribute_name under attribute type kset.
317 */
destroy_attribute_objs(struct kset * kset)318 static void destroy_attribute_objs(struct kset *kset)
319 {
320 struct kobject *pos, *next;
321
322 list_for_each_entry_safe(pos, next, &kset->list, entry) {
323 kobject_put(pos);
324 }
325 }
326
327 /**
328 * release_attributes_data() - Clean-up all sysfs directories and files created
329 */
release_attributes_data(void)330 static void release_attributes_data(void)
331 {
332 mutex_lock(&wmi_priv.mutex);
333 exit_enum_attributes();
334 exit_int_attributes();
335 exit_str_attributes();
336 exit_po_attributes();
337 if (wmi_priv.authentication_dir_kset) {
338 destroy_attribute_objs(wmi_priv.authentication_dir_kset);
339 kset_unregister(wmi_priv.authentication_dir_kset);
340 wmi_priv.authentication_dir_kset = NULL;
341 }
342 if (wmi_priv.main_dir_kset) {
343 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &reset_bios.attr);
344 sysfs_remove_file(&wmi_priv.main_dir_kset->kobj, &pending_reboot.attr);
345 destroy_attribute_objs(wmi_priv.main_dir_kset);
346 kset_unregister(wmi_priv.main_dir_kset);
347 wmi_priv.main_dir_kset = NULL;
348 }
349 mutex_unlock(&wmi_priv.mutex);
350 }
351
352 /**
353 * init_bios_attributes() - Initialize all attributes for a type
354 * @attr_type: The attribute type to initialize
355 * @guid: The WMI GUID associated with this type to initialize
356 *
357 * Initialiaze all 4 types of attributes enumeration, integer, string and password object.
358 * Populates each attrbute typ's respective properties under sysfs files
359 */
init_bios_attributes(int attr_type,const char * guid)360 static int init_bios_attributes(int attr_type, const char *guid)
361 {
362 struct kobject *attr_name_kobj; //individual attribute names
363 union acpi_object *obj = NULL;
364 union acpi_object *elements;
365 struct kobject *duplicate;
366 struct kset *tmp_set;
367 int min_elements;
368
369 /* instance_id needs to be reset for each type GUID
370 * also, instance IDs are unique within GUID but not across
371 */
372 int instance_id = 0;
373 int retval = 0;
374
375 retval = alloc_attributes_data(attr_type);
376 if (retval)
377 return retval;
378
379 switch (attr_type) {
380 case ENUM: min_elements = ENUM_MIN_ELEMENTS; break;
381 case INT: min_elements = INT_MIN_ELEMENTS; break;
382 case STR: min_elements = STR_MIN_ELEMENTS; break;
383 case PO: min_elements = PO_MIN_ELEMENTS; break;
384 default:
385 pr_err("Error: Unknown attr_type: %d\n", attr_type);
386 return -EINVAL;
387 }
388
389 /* need to use specific instance_id and guid combination to get right data */
390 obj = get_wmiobj_pointer(instance_id, guid);
391 if (!obj)
392 return -ENODEV;
393
394 mutex_lock(&wmi_priv.mutex);
395 while (obj) {
396 if (obj->type != ACPI_TYPE_PACKAGE) {
397 pr_err("Error: Expected ACPI-package type, got: %d\n", obj->type);
398 retval = -EIO;
399 goto err_attr_init;
400 }
401
402 if (obj->package.count < min_elements) {
403 pr_err("Error: ACPI-package does not have enough elements: %d < %d\n",
404 obj->package.count, min_elements);
405 goto nextobj;
406 }
407
408 elements = obj->package.elements;
409
410 /* sanity checking */
411 if (elements[ATTR_NAME].type != ACPI_TYPE_STRING) {
412 pr_debug("incorrect element type\n");
413 goto nextobj;
414 }
415 if (strlen(elements[ATTR_NAME].string.pointer) == 0) {
416 pr_debug("empty attribute found\n");
417 goto nextobj;
418 }
419 if (attr_type == PO)
420 tmp_set = wmi_priv.authentication_dir_kset;
421 else
422 tmp_set = wmi_priv.main_dir_kset;
423
424 duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
425 if (duplicate) {
426 pr_debug("Duplicate attribute name found - %s\n",
427 elements[ATTR_NAME].string.pointer);
428 kobject_put(duplicate);
429 goto nextobj;
430 }
431
432 /* build attribute */
433 attr_name_kobj = kzalloc_obj(*attr_name_kobj);
434 if (!attr_name_kobj) {
435 retval = -ENOMEM;
436 goto err_attr_init;
437 }
438
439 attr_name_kobj->kset = tmp_set;
440
441 retval = kobject_init_and_add(attr_name_kobj, &attr_name_ktype, NULL, "%s",
442 elements[ATTR_NAME].string.pointer);
443 if (retval) {
444 kobject_put(attr_name_kobj);
445 goto err_attr_init;
446 }
447
448 /* enumerate all of this attribute */
449 switch (attr_type) {
450 case ENUM:
451 retval = populate_enum_data(elements, instance_id, attr_name_kobj,
452 obj->package.count);
453 break;
454 case INT:
455 retval = populate_int_data(elements, instance_id, attr_name_kobj);
456 break;
457 case STR:
458 retval = populate_str_data(elements, instance_id, attr_name_kobj);
459 break;
460 case PO:
461 retval = populate_po_data(elements, instance_id, attr_name_kobj);
462 break;
463 default:
464 break;
465 }
466
467 if (retval) {
468 pr_debug("failed to populate %s\n",
469 elements[ATTR_NAME].string.pointer);
470 goto err_attr_init;
471 }
472
473 nextobj:
474 kfree(obj);
475 instance_id++;
476 obj = get_wmiobj_pointer(instance_id, guid);
477 }
478
479 mutex_unlock(&wmi_priv.mutex);
480 return 0;
481
482 err_attr_init:
483 mutex_unlock(&wmi_priv.mutex);
484 kfree(obj);
485 return retval;
486 }
487
sysman_init(void)488 static int __init sysman_init(void)
489 {
490 int ret = 0;
491
492 if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
493 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Alienware", NULL) &&
494 !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
495 pr_err("Unable to run on non-Dell system\n");
496 return -ENODEV;
497 }
498
499 ret = init_bios_attr_set_interface();
500 if (ret)
501 return ret;
502
503 ret = init_bios_attr_pass_interface();
504 if (ret)
505 goto err_exit_bios_attr_set_interface;
506
507 if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
508 pr_debug("failed to find set or pass interface\n");
509 ret = -ENODEV;
510 goto err_exit_bios_attr_pass_interface;
511 }
512
513 wmi_priv.class_dev = device_create(&firmware_attributes_class, NULL, MKDEV(0, 0),
514 NULL, "%s", DRIVER_NAME);
515 if (IS_ERR(wmi_priv.class_dev)) {
516 ret = PTR_ERR(wmi_priv.class_dev);
517 goto err_exit_bios_attr_pass_interface;
518 }
519
520 wmi_priv.main_dir_kset = kset_create_and_add("attributes", NULL,
521 &wmi_priv.class_dev->kobj);
522 if (!wmi_priv.main_dir_kset) {
523 ret = -ENOMEM;
524 goto err_destroy_classdev;
525 }
526
527 wmi_priv.authentication_dir_kset = kset_create_and_add("authentication", NULL,
528 &wmi_priv.class_dev->kobj);
529 if (!wmi_priv.authentication_dir_kset) {
530 ret = -ENOMEM;
531 goto err_release_attributes_data;
532 }
533
534 ret = create_attributes_level_sysfs_files();
535 if (ret) {
536 pr_debug("could not create reset BIOS attribute\n");
537 goto err_release_attributes_data;
538 }
539
540 ret = init_bios_attributes(ENUM, DELL_WMI_BIOS_ENUMERATION_ATTRIBUTE_GUID);
541 if (ret) {
542 pr_debug("failed to populate enumeration type attributes\n");
543 goto err_release_attributes_data;
544 }
545
546 ret = init_bios_attributes(INT, DELL_WMI_BIOS_INTEGER_ATTRIBUTE_GUID);
547 if (ret) {
548 pr_debug("failed to populate integer type attributes\n");
549 goto err_release_attributes_data;
550 }
551
552 ret = init_bios_attributes(STR, DELL_WMI_BIOS_STRING_ATTRIBUTE_GUID);
553 if (ret) {
554 pr_debug("failed to populate string type attributes\n");
555 goto err_release_attributes_data;
556 }
557
558 ret = init_bios_attributes(PO, DELL_WMI_BIOS_PASSOBJ_ATTRIBUTE_GUID);
559 if (ret) {
560 pr_debug("failed to populate pass object type attributes\n");
561 goto err_release_attributes_data;
562 }
563
564 return 0;
565
566 err_release_attributes_data:
567 release_attributes_data();
568
569 err_destroy_classdev:
570 device_unregister(wmi_priv.class_dev);
571
572 err_exit_bios_attr_pass_interface:
573 exit_bios_attr_pass_interface();
574
575 err_exit_bios_attr_set_interface:
576 exit_bios_attr_set_interface();
577
578 return ret;
579 }
580
sysman_exit(void)581 static void __exit sysman_exit(void)
582 {
583 release_attributes_data();
584 device_unregister(wmi_priv.class_dev);
585 exit_bios_attr_set_interface();
586 exit_bios_attr_pass_interface();
587 }
588
589 module_init(sysman_init);
590 module_exit(sysman_exit);
591
592 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
593 MODULE_AUTHOR("Prasanth Ksr <prasanth.ksr@dell.com>");
594 MODULE_AUTHOR("Divya Bharathi <divya.bharathi@dell.com>");
595 MODULE_DESCRIPTION("Dell platform setting control interface");
596 MODULE_LICENSE("GPL");
597